Full opinion text
RIZLEY, District Judge. I. Findings of Fact The Action, The Parties, The Patents In Suit, And The Issues 1. This is a patent-infringement action brought by plaintiff Zenith Radio Corporation against defendant Admiral Corporation, both of which are incorporated under the laws of Delaware. The jurisdiction of this Court arises under the patent laws of the United States. 2. Defendant has a regular and established place of business at Oklahoma City, Oklahoma, in this District, at which it has committed acts of infringement as hereinafter set forth in these findings. Defendant has been duly served with process herein. This Court has jurisdiction of the action and the parties, and the venue is properly laid in this District. 3. Plaintiff is, and since their respective dates of issuance has been, the owner of United States Letters Patent Nos. 2,817,025, 2,821,954, 2,821,955, 2,821,956, 2,814,671, and 2,915,583, and by its complaint herein charges defendant with infringement of each and all of said Letters Patent. Letters Patent Nos. 2,817,025, 2,821,954, 2,821,955, and 2,821,956 (hereinafter respectively referred to as the ’025, ’954, ’955, and ’956 patents) relate to various electrical and mechanical features of a remote-control system for television receivers, marketed by plaintiff under the trade name Space Command. United States Letters Patent No. 2,814,671 (hereinafter referred to as the ’671 patent) relates to a noise-gated synchronizing-signal separator circuit for television receivers, marketed by plaintiff under the trade name Fringe-lock. United States Letters Patent No. 2,915,583 (hereinafter referred to as the ’583 patent) relates to a noise-gated synchronizing-signal separator and automatic-gain-control circuit, constituting a modified and improved form of the basic Fringeloek circuit. 4. Defendant is, and since its issuance has been, the owner of United States Letters Patent No. 2,498,333, and by its counterclaim herein charges plaintiff with infringement thereof. Said Letters Patent No. 2,498,333 (hereinafter referred to as the ’333 patent) relates to a spindle construction employed in automatic record-changer mechanisms. 5. In its answer to the complaint, defendant denies infringement and asserts the affirmative defense that all of plaintiff’s patents are invalid for want of invention. Other affirmative defenses set forth in the answer include a plea that plaintiff is prohibited from enforcing the ’025, ’954, ’955, and '956 patents by reason of unclean hands and that plaintiff is estopped by laches from enforcing the ’671 and ’583 patents against the defendant. 6. Plaintiff’s alleged infringement of defendant’s ’333 patent consists of selling record changers purchased by plaintiff from the V-M Corporation of Benton Harbor, Michigan, a large manufacturer of such products. Plaintiff acknowledges that the ’333 patent is valid and that it has sold record-changer spindles incorporating its invention. Plaintiff’s defenses to defendant’s counterclaim, are (1) that the defendant by virtue.of its dealings with the V-M Corporation had at least granted to said corporation an implied license to manufacture and sell the record-changer spindle to the plaintiff and the general public, and (2) that defendant by reason of its conduct is estopped from now asserting the ’333 patent against plaintiff. 7. The lawsuit and these findings may conveniently be separated into the following three parts: (1) remote control, especially for television receivers, involving the '025, ’954, ’955, and ’956 patents; (2) noise-gated, synchronizing-signal separator circuit for television receiver involving the ’671 and ’583 patents; and (3) spindle construction for automatic-record changing mechanisms. involving the defendant’s ’333 patent. History Of The Space Command Development 8. “Remote control” of a television receiver refers to an arrangement by which a viewer, seated some distance from the set, can change channels, change the sound level, or turn the set on and off without actually rising and walking over to the set. Remote-control devices are not restricted in their usefulness to television; they are a convenience in the operation of radio receivers, and the radio industry tried for years to develop a remote control system for radio sets unsuccessfully. With television, remote control has a more important status than with radio because a television set must be watched at a distance greater than arm’s length. A remote-control device, whatever its field of application, consists basically of a transmitting device, accessible to the operator by which he can transmit a “command” for operation of the device to be controlled, and an apparatus associated with the controlled object for receiving the operator’s “command” and carrying it out. 9. In past years many different systems for remotely controlling radio sets, television receivers, and other electrical devices have been suggested, with a wide variety of apparatus used for generating, transmitting, and executing “commands”. Perhaps the simplest scheme for remote control involves running a wire cable between a control box and the television set or other device to be remotely controlled. In systems of this kind, the operator gives his “commands” by pressing buttons or turning knobs on the control box, which in turn actuate electrical switches; the “commands” are transmitted in the form of electric currents through the wire cable. Numerous companies, including both parties to this action, have manufactured remote-control systems of this kind for operation of television receivers and radio sets, but all of such systems failed commercially. The failure of such systems was due, at least in considerable degree, to’ the fact that a wire cable running across a floor is dangerous, unsightly, and easily damaged. 10. Another type of remote-control system for radio and television receivers, often suggested in the literature and tried out commercially by the Philco Company about 1938, employed radio waves' for communicating commands between the control box and the receiver. In this type of system, the control box was a miniature radio transmitter. This type of remote-control system has never been commercially successful. Its failure was due, first, to the fact that the control box of such a system necessarily contains delicate electronic parts and batteries, rendering it fragile and requiring periodic replacement of parts, and, second, to the fact that radio waves travel freely through walls, making such systems impractical for use in apartment buildings. 11. Still another remote-control system, commercialized some years ago by plaintiff, used light flashes for communicating between the operating position and the .television cabinet, electric-eye devices being built into the television cabinet to receive the flashed “commands”. This system also had little public acceptance. The manual control box— actually a special type of flash light— required periodic replacement of batteries, the device had to be carefully ■“aimed” at the particular electric eye to be actuated for carrying out any given command, and the system was subject to accidental operation by lights other than those from the control instrument. 12. None of the aforedescribed remote-control systems, nor any other prior art systems for remotely controlling home radio or television receivers, achieved any sustained success. Despite years of effort by qualified experts working with full knowledge of the need and doing their best to satisfy that need, no remote-control system for radio or television ever succeeded commercially until Zenith’s Space Command system appeared. 13. Zenith’s Space Command system is a remote-control system in which “ultrasonic” sound waves — i. e., sounds too high in pitch to be heard by the human ear — are used for communicating “commands” across the space between the operator’s position and the television receiver or other instrument to be controlled. 14. In Space Command, the transmitter or control box is a small, hand-held instrument provided with push buttons, labeled to identify the various receiver functions that each button controls. It is entirely mechanical, containing no tubes, no electrical parts, and no batteries. The transmitter is rugged and capable of withstanding rough handling and occasional dropping. It can be operated equally well in any position, does not have to be “aimed” at the television set, and requires no manual skill. In operating the transmitter, the user simply presses the button that governs the desired function, such as television tuning, and thereby generates an ultrasonic impulse of a particular frequency assigned to the selected function. 15. The ultrasonic impulses represent “commands” and travel through the air to the television set, where they are picked up by a microphone, and are converted to corresponding electric impulses. The microphone is a part of the receiver portion of the Space Command system, the remainder of the receiver comprising electrical circuits which amplify each “command” impulse derived from the microphone, sense its pitch or frequency, and operate a particular relay connected to perform the tuning or operating functions called for by the “command” impulse. 16. Space Command is a truly integrated system in which each component cooperates uniquely with the other components to provide dependable, trouble-free operation. The mechanical transmitter is tailored to produce sound impulses of a predetermined duration and definite frequency according to the particular button pressed by the user. The receiver circuit is correspondingly tailored to respond only to received sound impulses having the appropriate duration and having one or another of the definite frequencies used in the system. Circuits are provided in the receiver which enable it to distinguish effectively between the ultrasonic impulses generated by the transmitter and random ultrasonic noises, such as are caused by rattling of keys or tinkling of glasses, that are frequently present in a home environment and which, in the absence of such protective circuits, would produce spurious operation of the control relays. The mechanical and electrical components of the Space Command system are so designed and constructed that the system will operate equally well whether the transmitter be operated directly in front of the receiver or across a large room from it, at a distance of thirty or forty feet. Because ultrasonic waves do not pass through walls, the Space Command system is entirely free from interference between television sets in adjacent apartments or different rooms of a house. 17. The Space Command system was conceived in the latter part of 1955 by Dr. Robert Adler, Zenith’s Associate Director of Research. At that time, Zenith already had considerable experience with remote-control systems of other kinds. It had manufactured television sets with other kinds of remote-control systems. Its management understood their inadequacies and non-acceptance by the public. It urged its engineering and research people, including Dr. Adler, to give thought to the problem of a better remote-control system. Dr. Adler, after reviewing a number of possible approaches to the problem, suggested, as a promising avenue of research, a multiple-channel remote-control system in which ultrasonic sound impulses of different frequencies (i. e., pitches) would be used to carry “commands” from the operator’s position to the television receiver, each frequency being used in connection with a particular control function. Dr. Adler realized that, with this approach, a wholly mechanical transmitter might be possible. 18. An experimental project was undertaken by Dr. Adler’s research group, directed to trying out the basic aspects of the system and determining its practicability. The early phases of this project included both experimental work by Dr. Adler on the development of a suitable receiver circuit and several projects, under Dr. Adler’s direction, directed to determining whether ultrasonic sound impulses could, as a practical matter, be successfully used in homes as a remote-control communication medium. 19. Dr. Adler was convinced that any successful system would necessarily include a push-botton transmitter that would operate mechanically, rather than by use of electrical circuits and batteries. He considered various possible means of producing ultrasonic sound impulses mechanically and decided to try cylindrical metal rods struck on their ends by hammer blows to generate vibrations in the so-called “longitudinal mode”. In this mode of vibration, a rod vibrates longitudinally, alternately shrinking and expanding outwardly from its center, along the longitudinal axis. This type of sound generator not only appeared promising from the economy standpoint but had the advantage of being large enough in size to radiate powerful sound impulses into the air. (Other known types of vibrators, such as bells, gongs and other forms of transverse mode vibrators, if designed for operation in the ultrasonic frequency range, would be so small in size as to radiate poorly and, further, they present serious manufacturing problems.) 20. Considerable experimental work was done on various types of rod materials, and a particular type of commercially available aluminum alloy was chosen as the most satisfactory material from the standpoints of performance, availability, and cost. A particular advantage of aluminum rods was that they proved to have excellent energy-storage properties, vibrating for a long time after being struck. (This property of a resonator is referred to in engineering parlance as the “Q” i. e., “quality factor” and is measured numerically, the energy-storage properties of a given material being directly proportional to its “Q” number.) 21. During the early work on the Space Command project, the experimental resonator rods, held at the center between thumb and forefinger or by means of surgical tweezers, were manually struck by small hammers. As soon as it was definitely determined that ultrasonic signals of suitable intensity, frequency, and duration for remote-control purposes could be generated in this way, and after the experiments had established that such impulses would travel far enough through air, work was started on the development of a practical hand-held, push-botton transmitter. This project became the direct responsibility of an engineering group under the direction of Clarence W. Wandrey, Zenith’s chief mechanical engineer. Dr. Adler, however, kept in close touch with the work and maintained an active advisory control over it. 22. Design of a suitable hand transmitter for the new system required solution of many problems. To provide the sound intensity necessary for remote control at distances of thirty to forty feet, the resonator rods had to be struck hard, giving off a pure tone of a definite frequency. At the same time, the striker mechanism had to be easily operable without excessive finger pressure, in order that the transmitter could be readily operated by a woman or child. Moreover, Zenith’s engineers learned that the transmitter must somehow be constructed to insure that the finger-operated hammer would strike the resonator rod only once for each button movement. Multiple hammer impacts, it was found, weakened the generated sound and caused it to die out quickly. Another major problem that had to be overcome was mounting of the resonator rods in the transmitter box. They necessarily had to be mounted in a way that would hold them securely against dislodgment under the impact of hammer blows; at the same time the mounting structure must not reduce the “Q” of the rods appreciably. Another problem involved finding a suitable, economical means of ending the rod vibration when the push button was released. Otherwise, it was learned, the emitted sound impulse might last so long as to produce multiple operation of the remote-control relays. 23. One by one, these problems were solved; the mechanical inventions by which they were solved are described in and covered by the '954, ’955, and ’956 patents in suit. The hand-held, finger-operated ultrasonic transmitter which embodied these inventions was a truly new product. So far as appears from the record, nothing structurally or functionally like it had ever been built before. 24. Another technical problem studied and solved by Dr. Adler and his associates was the selection of pitches (frequencies) of ultrasonic signals to be used in the remote-control system. After experimenting with several different ranges of pitch, Dr. Alder selected a range of frequencies in the neighborhood of 40,000 cycles (40 kilocycles) as most satisfactory from the standpoints of resonator size, weight, effective distance range, and freedom from interference with the electrical circuits in the television receiver itself. 25. While the mechanical transmitter was being developed, Dr. Alder carried on a concurrent research program with respect to the receiver portion of the remote-control system. This part of the work carried with it its own special problems. It v/as necessary to provide a receiver which would amplify enormously the weak electrical signals derived from the microphone, to permit successful remote control at distances of thirty to forty feet; at the same time, the receiver must possess electrical stability. The requirements of the system called for a circuit that would accurately and effectively distinguish between ultrasonic signals of one frequency and another, in order that the ultrasonic “commands” be accurately interpreted and carried out, without confusing a command for controlling one function with a command intended to perform another function. Reduction in number of components and circuit complexity was itself a major problem, since the cost of the system had to be held within reasonable bounds if it were to be salable as a consumer product. 26. One of the most critical problems faced by Dr. Alder in the development of the receiver circuit was undoubtedly that of insuring dependable relay operation in response to the ultrasonic commands from the transmitter, as received under practical conditions, while at the same time avoiding relay operation in response to rattling keys and other random ultrasonic noises picked up by the microphone. This problem was made especially difficult by the circumstances under which Dr. Adler intended his remote-control system to work. Rather than having strong command signals from a power-driven sound source, as had been suggested in previous remote-control systems, Dr. Adler’s system had to operate on the relatively weak ultrasonic signals generated by a finger-actuated transmitter. Hence, ultrasonic noise at the receiver microphone was often stronger than the desired signals, especially when the signals came from a considerable distance. Further, the signals from the hand transmitter were not uniform in intensity throughout their duration, but, like other sounds produced by percussion, decayed or “died out” with passage of time. Ultimately, after extensive experimenting, Dr. Adler developed a receiver circuit in which a rather complex combination of elements cooperated to achieve the result he was seeking. This new receiver circuit successfully responded to ultrasonic signals of the desired frequencies and duration, even though they might be very weak and momentarily interrupted by noise or other cause. At the same time, the receiver exhibited almost complete immunity to ultrasonic noises-and other forms of interference. This receiver circuit, invented by Dr. Adler, became the subject matter of the ’025 patent in suit. 27. Zenith’s research program which resulted in the Space Command remote-control system took place between October of 1955 and February or March of 1956. The new remote-control system represents the distilled and refined product of endless hours of thought, experiment and effort. It was ready for commercial production shortly before the middle of 1956, and was first introduced publicly, under the trade name “Space Command”, in the summer of that year. The Space Command Patents And The Defenses Asserted Against Them 28. The invention of the ’025 receiver patent, in its simplest or basic form, involves a circuit combination which, in conjunction with a microphone and amplifier, includes a limiter, a frequency discriminator, an integrator circuit, and a biased relay control tube, also referred to as an amplitude discriminator. The elements of this basic combination are so adjusted as to provide relay operation only in response to signals of predetermined frequency and predetermined minimum duration and duty cycle. By this combination of circuit elements, which work by cooperative action, Dr. Adler achieved a new result — namely, a receiver circuit which would reject noise, while at the same time responding to signals of the desired “command” frequency, even though interrupted, if they were present in the discriminator output at the amplitude-limited level for a predetermined percentage of the normal duration of a command impulse. The recommended adjustment for duty cycle in the ’025 patent is to set the relay actuating voltage at a level between 50% and 65 % of the maximum limited output voltage of the discriminator. The new result of the Adler circuit invention was rejection of noise concurrently with successful reception of command signals despite signal interruptions caused by noise interference, echoes, or other factors.- 29. In addition to the basic circuits described in the foregoing finding, the Adler receiver invention included other features which were new in the over-all combination. One of these was the use, in a multi-function remote-control system, of a dual-frequency discriminator having two output connections respectively fed to two distinct relay control tubes, controlling different and independent functions. By this novel circuit feature, Dr. Adler was able to- use a single frequency discriminator for two control channels, thereby achieving considerable reduction in the total number of parts required for a multi-channel receiver. This feature of the Adler ’025 invention was optional, being called for in some claims of the patent but not required in all claims. 30. In attempting to show invalidity of the ’025 patent in suit for want of invention, Admiral relied primarily on the previous work of one Boley Andrews, as disclosed in Andrews patent No. 2,739,273 and various other publications. Andrews himself appeared as a witness for Admiral, and both he and Admiral’s other expert witness on this phase of the case agreed that the disclosure of the Andrews patent No. 2,739,273 could be regarded as fairly representative of the Andrews prior art. In addition to the Andrews work, Admiral placed some reliance on Alexan-dersson patent No. 2,320,996, with respect to the dual-frequency, double-output feature of the ’025 patent. Various other prior-art references were cited by Admiral in respect to the ’025 patent, but only as showing sonic remote control in the broad sense. Hence consideration in those findings need be given only to the Andrews and Alexandersson references. 31. The Andrews prior art relates to an ultrasonic remote control for operation of garage doors, developed by Boley Andrews about 1946 or 1947. In this remote-control system, Andrews used as his transmitter an ultrasonic whistle driven by power from an automobile engine. This is conceded by Admiral to be irrelevant to the ’954, ’955, and ’956 Space Command transmitter patents. Only with reference to the ’025 receiver patent does Admiral rely on the Andrews prior art. 32. The remote-control receiver developed and used by Boley Andrews in his garage-door control system did resemble the Adler receiver described and claimed in the ’025 patent in a number of respects. It employed a microphone for picking up ultrasonic waves and converting them to electric-wave impulses, an- amplifier, a limiter, a discriminator, and a relay control system for operating a door-actuating relay in response to ultrasonic signals received by the microphone. The evidence establishes, however, that the Adler circuit differed sharply from the Andrews circuit in several ways. 33. A most important difference has to do with the so-called “duty cycle” function of the Adler circuit, by means of which the Adler circuit is rendered immune to spurious actuation by noise while having at the same time the ability to respond to command impulses of normal duration which are momentarily interrupted by noise or momentarily can-celled out by echo reflections. Mr. Andrews himself acknowledged that his circuit does not operate like the Adler circuit in respect to the duty-cycle function, and is not capable of achieving the results of the Adler circuit. Andrews admitted that his circuit would not respond to any signal that was interrupted for even so much as a few thousandths of a second during its minimum duration, relay operation in the Andrews system requiring a continuous, uninterrupted signal for the entirety of a prescribed period, recommended in the Andrews patent to be three seconds. 34. Another significant difference between the Adler circuit and the Andrews prior art relates to Adler’s dual-frequency discriminator from which two output signals are separately fed to two different relay control tubes, a single discriminator being thereby employed for two different and independent remote-control functions. None of the Andrews prior art discloses any such arrangement. Andrews did use two different frequencies in his garage-door control systems, to prevent neighbors from inadvertently opening one another’s garage doors. He did not, however, use two frequencies in any one garage-door opener, the receivers for the so-called “red” and “blue” frequencies having been separately manufactured and tuned. In the one piece of Andrews equipment which used two frequencies — an ultrasonic flaw detector and not a remote-control device — Andrews employed a receiver having two separate discriminators, one for each frequency, rather than utilizing a single discriminator for two different remote-control frequencies as Adler did. The Andrews prior art also lacked a further Adler optional feature of a frequency-multiplying circuit in the receiver that would produce amplitude-limited signals at a multiple, greater than one, of the ultrasonic signals. 35. The only item of prior art relied on by Admiral as a forerunner of the' Adler dual-frequency, double-output discriminator circuit was the Alexandersson patent No. 2,320,996, but this patent clearly lacks the Adler inventive concept. Alexandersson described a system for remotely controlling a rotating object by-means of a continuous electrical signal, control being accomplished by varying the' frequency continuously within a predetermined range. In Alexandersson’s receiver, a frequency discriminator circuit having two output connections was used.. These connections, however, both fed the same amplifier and were not used, as. Adler uses them, to carry separate control signals to separate load devices, each independently operable without the other. In the Alexandersson system, the signals, from the two discriminator output terminals always operated in conjunction, like the opposite ends of a teeter-totter, both cooperating in the achievement of a single-control function. The Alexandersson frequency discriminator is not the same as that of Adler, and there is no suggestion,, in the Alexandersson patent or in any-other prior art, which would lead a skilled' reader to modify the Alexandersson discriminator in the manner necessary to* make it work like the Adler invention. 36. The invention of the ’025 Adler-patent is novel in structure and does achieve a new and useful result in an unobvious way, not taught or suggested by any prior art. It is therefore a patentable invention, and Admiral has failed! to sustain its burden of proof with respect to its plea that the ’025 patent is invalid for want of invention. 37. The ’954 patent, of which Dr.. Adler is the inventor, is directed to a mechanism by which the ultrasonic vibrations from the transmitter resonator rods, are automatically damped — i. e., suppressed — when the push button is released. The utility of this invention consisted in controlling the duration of the ultrasonic command impulses so that the remote-control relays in the television receiver would operate only once for each ■command. The mechanism described in and covered by the ’954 patent embodied the novel principle of damping the longitudinal-mode resonator by applying a movable damping element to the side of the resonator rod when the push button is released, the mechanism also including means for moving the damping element ■out of contact with the rod during the part of the push-button movement that produces the hammer impact' on the rod. This method of damping a longitudinal-mode resonator was advantageous in that it permitted the use of an inexpensive metal damping element, such as a piece of spring wire, to damp out the vibrations by frictional contact with the side of the rod. This is in contrast to the previously known method of damping longitudinal-mode vibrators by applying a damping member to the end face of the rod. End damping will work successfully, but it requires the use of a soft damping material. The vibrations on the end face will throw a metallic damping element away from contact with the rod, producing “chatter” ■ — i. e., rattling — and ineffective damping action. 38. In attempting to show invalidity of the ’954 patent for want of invention, Admiral relied, as prior art, on Morris patent No. 1,490,476, Gardiner patent No. 2,167,600, Rest patent No. 2,512,777, and White patent No. 2,728,902. Admittedly, none of these patents anticipates the subject matter defined in the claims of the Adler ’954 patent in suit. The issue to be resolved, therefore, is whether, in view of these prior-art patents, the ’954 invention would have been obvious at the time it was made to a person of ordinary skill in the art. 39. The Morris patent No. 1,490,476 relates to an electrically operated door chime. The chime shown in Morris is a hollow metal tube, caused to ring by being struck on its side by an electrically operated hammer. The damper described by Morris is a cushioned element which, as the hammer moves away, is brought into contact with the end of the chime tube. The Morris chime is not a longitudinal-mode vibrator, the damper does not engage the side of the vibrator, and the chime is not push-button actuated. The Morris patent fails to disclose any of the specifically defined features of the Adler ’954 invention. 40. The Gardiner patent No. 2,167,600 relates to a musical instrument, and its disclosure is similar to that of the Morris patent, so far as the features here under consideration are concerned. Gardiner, like Morris, does not describe a longitudinal-mode vibrator, but rather rods or bars which are caused to vibrate transversely by being struck on their sides. Damping in the Gardiner device is accomplished by an electrically actuated end damper, consisting of a disc covered with a pad of felt or rubber. The timing of the hammer-striking and damping actions is controlled in the Gardiner device by an electric circuit. Thus Gardiner fails to disclose any of the features of the invention specifically defined in the claims of the ’954 patent, and, if anything, is even more remote from the invention of that patent than the Morris reference already mentioned. 41. The Rest patent No. 2,512,777 is another reference dealing with a musical instrument. It does not deal with longitudinal-mode vibrators, and it has no separate damping element. In the Rest device, tubular transverse vibrators are made to ring by being struck on the sides with hammers, and the vibrations are damped simply by permitting the hammers to return into contact with the vibrators following the initial blow. The Rest device does not have any of the claimed features of the ’954 invention. 42. The White patent No. 2,728,902, which was considered by the Patent Office during the prosecution of the ’954 patent, does disclose an ultrasonic generator employing a longitudinal-mode cylindrical vibrator. In the White device, the vibrator is excited by being struck on its end by a motor-driven hammer. White damps the rod vibrations, however, by means of an end damper, consisting of a doughnut-shaped ring of cork, felt, or rubber, mechanically arranged to move into contact with the end of the rod shortly after the rod is struck by the hammer. The hammer strikes the rod by passing through the hole in the doughnut-shaped damper. In another form of the White device, he discloses a so-called “damper” consisting of a stationary vibration-absorptive ring permanently clamped onto the rod some distance from its end. This is not a “damper” in the sense in which that term is used in the ’954 patent — i. e., a device which is out of contact with the vibrator when it is struck and which later touches the vibrator to make it stop vibrating. This last-mentioned White damping ring is a device which cuts down the vibrations of the rod at all times, even at the instant of hammer impact. It operates as a constant load or “drag” on the vibrating rod. The first-mentioned White damper is a true damper in the sense of the Adler invention, but it does not operate by bearing against the side of the rod, as in Adler, but on the contrary presses against the end face of the rod, damping the vibrations on the same part of the rod where the hammer blows take place. 43. Admiral contends that the Adler ’954 invention would, in view of the prior art, have been obvious at the time it was made to a person of ordinary skill. This contention is rejected. None of the prior art discloses the Adler concept of damping a longitudinal-mode resonator by contact with its side. That the Adler invention was not obvious is strongly indicated by the fact that White, working with a longitudinal-mode vibrator at a date years after issuance of the other cited prior-art patents, did not think of using a side damper such as Adler taught but, on the contrary, found it necessary to employ a mechanically elaborate end-damping arrangement with a doughnut-shaped, soft damping ring and a hammer arranged to pass through the central opening of the damper when striking the rod. The advantages of the Adler construction are clear; it permits use of a metallic damping element as opposed to the more expensive felt or rubber damper, and it avoids all problems of mechanical interference between the hammer and the damper. Had this concept been obvious, it seems most likely that White would have adopted it rather than going to the cumbersome and complicated system which he did use. 44. The invention of the ’954 patent is novel in structure, accomplishes a new and useful result, and would not have been obvious at the time it was made to a person of ordinary skill in the art. It is, therefore, a patentable invention. 45. The ’955 patent, of which Zenith’s engineers Robert C. Ehlers and Clarence W. Wandrey were joint inventors, covers the basic Space Command transmitter structure, consisting of an ultrasonic resonator rod mounted at its nodal plane, a hammer for striking the rod, a spring supporting the hammer near one end of the rod, and associated mechanism for causing the hammer to deliver a powerful single blow to the end of the rod in response to a manual push-button actuation. The product covered by this patent is a novel article of manufacture, and its development as with the other Space Command patents, required simultaneous solution of several difficult problems. Successful remote control at considerable distances from the television set required that the transmitter of the Space Command system deliver powerful hammer blows to the resonator rods to produce sound impulses of the necessary high intensity. These blows, however, had to be produced by a relatively light finger movement to permit operation of the instrument by women and children. The mechanism, moreover, had to be so constructed that a single finger movement would produce only oné hammer blow on the rod. At an early stage of their experimental work, Zenith’s engineers had discovered that multiple hammer impacts would damp out and weaken the sound impulse produced by the first blow, rather than reinforce it. Along with these technical demands, the transmitter mechanism had also to satisfy practical requirements — -it had to be mechanically rugged, capable of operation in any position, and reasonably inexpensive in construction. 46. The structural combination described in and covered by the ’955 patent satisfied all the requirements noted in th« foregoing finding. The patent teaches that the weight of the hammer, the resiliency of its spring support, and the spacing between the hammer and the rod should be so proportioned that the hammer is able, when tripped, to strike the rod only once for each push-button movement. 47. In attempting to show invalidity ■of the ’955 patent for want of invention, Admiral relied, as prior art, on Treanor patent No. 1,357,915 and Connell patent No. 186,416. These patents, whether treated singly or taken together, do not anticipate the subject matter defined in the claims of the ’955 patent. Hence the issue to be resolved is whether the ”955 invention, as a whole, would have been obvious at the time it was made to a person of ordinary skill in the art, in view of the Treanor and Connell patents. 48. The Treanor patent No. 1,357,915 relates to a signal gong, intended for use in mines, consisting of a bell with mechanism mounted inside for ringing it when a cord or chain is pulled. The structure disclosed by the Treanor patent is not responsive to the claims of the ’955 patent in suit, and it differs from the ’955 invention in several respects. Admittedly, the bell of the Treanor patent is a transverse-mode and not a longitudinal-mode vibrator. Treanor’s bell was not a generator of any specific ultrasonic frequency ; on the contrary, it was a resonator which, upon being struck, would give off a great variety of different tones and pitches. Further, Treanor’s mechanical structure is quite different from that described and claimed in the ’955 patent. For one thing, the Treanor device has no separate hammer; it used as its impact member the same metal bar that serves, according to Admiral’s expert witness, as an “exciter tensioning means”. In the ’955 patent, on the other hand, the hammer or “exciter” is carried on one end of a spring which is distinct from the “exciter tensioning means”. This spring, in the structure of the ’955 patent, plays an important part in the single-impact operation of the device, and it admittedly has no counterpart in the Treanor device. Finally, the Treanor patent discloses no apparatus for restricting to a single blow the impact of the “exciter tensioning means” against the inner surface of the bell when the chain has been pulled, nor does Treanor teach the desirability of such a construction. 49. The Connell patent No. 186,416 was granted in 1877 and is thus 83 years old. It discloses a manually operated door bell, in which manual pressure on a push-button causes the bell to ring. The mechanism of this old Connell door bell patent is quite different from that described and claimed in the ’955 patent and it lacks entirely the distinctive novel features of the ’955 invention. Specifically, the Connell door bell does not make use of a longitudinal-mode vibrator, it does not generate a specific ultrasonic frequency, and contains neither apparatus for insuring a single impact between the clapper and the bell nor any teaching that such single impact would be desirable. 50. The White patent No. 2,728,902, which was cited by the Patent Office in the prosecution of the ’955 patent, is a closer reference, insofar as the ’955 invention is concerned, than either the Treanor or Connell patents. 51. While admitting that none of the prior art cited against the ’955 patent anticipates its claimed subject matter, Admiral contends that the ’955 invention as a whole would, in view of such prior art, have been obvious at the time it was made to a person of ordinary skill. This contention must be rejected. None of the prior art discloses the basic concepts of the ’955 invention, nor does any prior art disclose a product similar in structure and purpose to the ultrasonic transmitter of the ’955 patent. The record shows that many skilled persons had worked to provide a successful remote-control device for radio or television, during the three decades immediately preceding the development of Zenith’s Space Command. Some of those systems operated on sonic principles. Yet no one, in all the history of that work, ever suggested or taught how to make a product such as the Space •Command transmitter. In the prior art electrically operated tuning forks, power-•operated whistles, breath-operated whistles, and the human operator himself were suggested as sources of sound for •operating sonic remote-control devices. There is no suggestion in that prior art, Ihowever, of a hand-held, finger-operated •ultrasonic generator. Since Zenith introduced such a product, hundreds of thousands of them have been made and sold. In view of its clear advantages over other forms of sound generators for remote-•eontrol systems, as well as its structural .simplicity and low cost, the Space Com:mand transmitter would almost certainly have been suggested long ago if its concept had been obvious as Admiral contends. Certainly many persons skilled in •the art had been unsuccessfully seeking ¡such a device over a period of years. 52. The invention of the ’955 patent is novel in structure, accomplishes a new .and useful result, and would not have ibeen obvious at the time it was made to :a person of ordinary skill in the art. It is, therefore, a patentable invention. 53. The ’956 patent, of which Zenith’s •engineer Ole E. Wold (now deceased) was ■.the inventor, relates to the means used in 'the Space Command transmitters for ■mounting the resonator rods within the 'transmitter case. The mounting device ■of the ’956 patent represented solution of ,a difficult problem. A longitudinal vibrator, as exemplified by the resonator rods of the Space Command transmitter, vibrates by shrinking and expanding outwardly from its middle portion toward its ends. Hence, the vibration is greatest ■at the ends of the rod and, theoretically, is almost zero at the central plane of the rod; that is, the plane which crosses the rod at right angles, exactly midway between its ends. This region of minimum vibration is called the “nodal plane”, and it is the best region in which to mount the rod. The most important requirement for a successful mounting is that it must make a minimum of contact with the rod, so as to interfere as little as possible with the vibration, maintaining the “Q” of the rod as high as possible. A good mounting for an application such as the Space Command transmitter also must be mechanically rugged and capable of holding the rod securely in place, even under the force of the powerful hammer blows by which the rod is made to generate ultrasonic impulses. Further, because cutting away material from the center of a rod changes its pitch or frequency, it was desirable that the rod mounting should require a minimum cutting away of rod material — the less the better, in the interest of facilitating mass production of uniform-frequency rods. 54. The rod mounting of the ’956 patent, by which the foregoing problems were solved, consisted in anchoring a pair of spring wires on a rigid metal bracket, spaced apart by a distance slightly less than the rod diameter, cutting oppositely disposed narrow grooves in the resonator rod along its nodal plane, and sliding the rod between the spring wires, which snap into the grooves and lock the rod in position. Because the spacing between the spring-wire supports on the bracket is less than the diametric spacing between the grooves, the wires engage the grooved rod only at a limited number of points, the springs “bowing” outward from their bracket anchors and gripping the rod tightly between them. In the preferred form of the invention, the grooves were made in the form of flat-bottomed slots diametrically opposed in the nodal plane of the rod, so that the bowed spring wires made contact with the rod only at four separated points, at the respective ends of each slot. In this preferred construction, the pressure at each of the four spaced contact points is enormously high, and the rod is therefore held securely by the spring wires against both longitudinal and lateral dis-lodgment. The contact area between the bowed springs and the rod surface in the '956 invention is so small that the mounting structure does not have any appreciable effect on the vibration of the rod and does not significantly reduce its “Q”. 55. In attempting to show invalidity of the ’956 patent for want of invention, Admiral relied, as prior art, on the White patent No. 2,728,902, the Rowe patent No. 2,516,725, the Lutzens patent No. 2,304,835, and a publication in Physics magazine. Admiral acknowledges that none of these references anticipates the subject matter defined in the claims of ’956 patent in suit. Here again, therefore, the issue to be resolved is whether, in view of prior art, the ’956 invention, as a whole, would have been obvious at the time it was made to a person of ordinary skill in the art. 56. The Rowe patent discloses a musical instrument containing metal rods suspended by strings looped around the rods. The rods disclosed in Rowe were not longitudinal-mode vibrators and Rowe does not disclose or suggest spring wires for rod mounting. The Rowe patent is not a pertinent reference with respect to the ’956 invention. 57. The White patent No. 2,728,902, which was cited by the Patent Office in the prosecution of the ’956 patent, discloses a mounting for a longitudinal-mode vibrator in which the rod is provided with a circumferential groove in its nodal plane and is held by a pair of clamping ribs curved to fit tightly in the groove. This general type of rod mounting was among those tried out experimentally by Zenith’s research workers and discarded because it cut down the “Q” of the rods too much. Admiral also tried such a mounting and discarded it for the same reason, adopting instead the spring wire mounting of the '956 patent. There is admittedly no teaching or suggestion in the White patent that spring mounting means could be used for supporting the longitudinal-mode vibrator. 58. The Physics magazine article, relied upon by Admiral as prior art against the ’956 patent, describes a series of laboratory experiments made in measuring the physical properties of various materials, including metals of several kinds, hard rubber and glass. In these experiments the authors made their measurements on cylindrical rods fashioned of the various materials to be tested, the rods being set into vibration by electromagnetic means rather than being struck with a hammer. As a means of supporting the experimental rods, the authors described a sling arrangement in which the rods were supported by two pieces of very fine piano wire, one piece being wrapped approximately half way around the rod and the other piece being wrapped around the other portion of the rod diameter. Both wires were anchored to fixed pins at the comers of a square frame. Physical specimens of the wire sling mounting of the Physics article were demonstrated to the Court by both parties. These demonstrations have shown that the rod mounting described in the Physics article was an extremely sensitive, delicate structure, capable of holding a rod in a precarious balance for a laboratory experiment but wholly unsuited for supporting resonator rods in a hand-held ultrasonic transmitter in which the rods were to be excited by hammer blows. The slightest tilting of the Physics mount resulted in swinging and tilting of the rod. There is no teaching or suggestion in the Physics article concerning the use of grooves in connection with the wire sling mounting therein described, and there is also no suggestion or teaching of disposing the rods within a spring wire support that makes contact with the rod only at a limited number of spaced points. On the contrary, the wire sling mounting of the Physics article touches the rod continually throughout the major part of its circumference. The courtroom demonstrations showed that the sling mounting of the Physics article was still very unstable even when used in conjunction with a grooved rod. The Physics article does not teach any of the distinctive and novel features of the ’956 invention. 59. The Lutzens patent No. 2,304,835 deals with various arrangements for mounting piezo-electric crystals with wires which, in addition to supporting the crystal, also act as electric conductors for carrying current to the plated conductive surfaces of the crystals. The teachings of this patent are wholly irrelevant to the ’956 invention. The wires 'disclosed in the Lutzens patent are not .spring wires as required by the ’956 invention, but are simply ordinary wire 'conductors. The crystals described by Lutzens were, for the most part, transverse-mode vibrators, and the wires of the Lutzens circuit were in direct contact with the plated surfaces of the crystal throughout their length. Indeed, Lut-zens suggested that these wires should even be cemented to the plated crystal surfaces. Lutzens did disclose one form of crystal which vibrated in a manner analogous to longitudinal-mode vibration. For this crystal, however, he taught a mounting which made a surface contact with the vibrating faces of the crystal for substantial distances adja.cent the edges of the crystal faces. Considered as a whole, the Lutzens patent ■clearly deals with quite a different problem from that involved in the ’956 invention and none of the mounting means .■suggested in Lutzens is analogous in ■structure, function or result to the ’956 .'invention. 60. The Court rejects Admiral’s contention that the ’956 invention, as a •whole, would have been obvious at the time it was made to a person of ordinary ■skill, in view of the prior art. None of the prior art discloses the combination •of grooved rod and spring-wire support described and claimed in the ’956 patent. 'The prior art lacks completely any teaching of the basic concept of the ’956 patient, by which a grooved rod is used in •conjunction with spring wires spaced apart slightly less than the rod diameter, so that they bow when the rod is forced between them and hence contact the rod .at only a limited number of spaced points. Since both the structure and the concept •of the ’956 invention is absent from the ■prior art, the invention, as a whole, was not obvious. This is confirmed by the fact that Admiral, after unsuccessfully trying a number of other mountings, ■found it necessary to copy Zenith’s rod •mounting. 61. The invention of the ’956 patent is novel in structure and concept, accomplishes a new and useful result, and would not have been obvious at the time it was made to a person of ordinary skill in the art. It is, therefore, a patentable invention. 62. The Court finds from all of the evidence in this case that Zenith’s remote-control patents, the '025, '954, ’955, and ’956 patents, are each and all of them valid and legal in every respect. The Court further finds that said patents and their respective claims are new and novel combinations; they were not anticipated by prior patents or publications, and there was no erroneous designation of inventors. The Court also finds that the disclosures and teachings in the claims are adequate; that the prior art relied upon by Admiral, whether cited or not cited by the Patent Office against Zenith’s patents, is not such that the inventions of said patents would have been obvious to those skilled in the art. 63. Admiral pleaded that the Space Command patents in suit were unenforceable by Zenith by reason of alleged unclean hands in connection with the prosecution in the Patent Office of the ’025 patent. The plea of unclean hands rested on the charge that Zenith’s patent solicitors wrongfully filed and prosecuted the application which matured into the ’025 patent without bringing to the attention of the Patent Office the prior art patent to Andrews, No. 2,739;273, the existence of which was known to Zenith’s solicitors at the time they filed the ’025 application. 64. The undisputed facts on which Admiral’s charge of unclean hands must be judged are as follows: The subject matter of the ’025 patent was first presented to the Patent Office in April, 1956, as a part of the patent application which ultimately became the ’954 patent. At that time Zenith’s solicitors were not aware of the existence of the Andrews prior art patent. In early 1957, the Patent Office issued a ruling that the 1956 application included two distinct areas of invention and required that the application be divided into separate applications. In August, 1957, the divisional application which ultimately became the ’025 patent was filed with claims drawn to the Adler remote-control receiver circuit. Sometime between June 19, 1956, and August 4, 1957, Zenith through its service department, learned of the Andrews remote-control system for opening garage doors, which was being manufactured and sold by the Vendo Company. Following this discovery, Zenith’s patent department made a check of the Patent Office indexes to determine what patents had been issued to Vendo Company, and, in doing so, discovered the Andrews Patent No. 2,739,-273. When the divisional application that ultimately became the ’025 patent was being prepared, Zenith’s patent solicitors reviewed its claims and satisfied themselves, in their professional judgment, that all such claims distinguished the Adler invention patentably from the Andrews patent and all other prior art known to them. The claims of the divisional application included eight claims taken over bodily from the 1956 parent application and three new claims. All the claims specified a circuit having Dr. Adler’s duty-cycle feature, which is not disclosed in the Andrews patent, or any other prior art of record. In.addition, most of the claims in the divisional application distinguished from the Andrews patent in other respects as well, such, as by reciting the Adler circuit in which a single discriminator is connected through two output connections to a pair of separate relay control circuits. The divisional application was filed, without any reference therein to the Andrews patent, and it was allowed by the Patent Office on the first official action. There is no evidence of record indicating that the Andrews patent was actually considered by the examiner who allowed the ’025 patent. 65. Zenith’s solicitors, in good faith, believed the ’025 invention, as defined in the claims drafted to cover it, was patentable over the prior art, including the .Andrews patent. Under those circumstances they were under no professional obligation or moral duty to cite the Andrews patent in the specification of the divisional application or otherwise to call it to the Patent Office’s attention while the application was pending. In-view of all of the facts of this case, the Court finds that Admiral has failed to-show any improper conduct on the part of Zenith’s patent solicitors. The unclean hands defense is, therefore,, without basis and is rejected. Admiral’s Copying Of Space Command 66. When Zenith’s Space Command' television receivers appeared on the market, they promptly attracted favorable attention in the industry, and Admiral almost immediately undertook to design and produce a competing product. At the-beginning, Admiral’s engineers tried to-develop a system of their own, using the broad concept of remote control by ultrasonic sound impulses but not necessarily copying directly the circuits and mechanical devices developed by Zenith for Space Command. Even so, Admiral’s, engineers had Zenith’s Space Command transmitters and television receivers in their laboratories, and they used them as models and guideposts for their own work. 67. Admiral’s engineering group assigned to design a manual transmitter-worked along original lines for only a brief interval. After unsuccessful experimenting with tuning forks as a means of generating ultrasonic signals,, and brief consideration of dog whistles-for that purpose, Admiral’s engineers decided to go straight down the pathway which Zenith had tracked out. They adopted cylindrical rods as ultrasonic-generators, made of aluminum of the same size and type used by Zenith. They adopted .the same band of frequencies-. Zenith had chosen. After trying out, without success, other schemes for mounting the resonator rods in the transmitter box, they adopted the same technique for resonator mounting that Zenith, after long research and study, had worked out for its use in the Space-Command transmitters. Admiral also-copied the sliding push-button actuator used in the Zenith transmitter, as well as the damper mechanism, invented by Dr. Adler, by which release of the push-button caused a metallic damper element to bear against the side of the vibrating rod, thus damping out the ultrasonic vibrations after the proper time interval. In the mass production of its aluminum resonator rods, Zenith had developed a technique for adjusting their pitch by drilling small radial holes at the rod centers; defendant copied that too. 68. It is clear and convincing that Admiral’s engineer initially assigned to work on the receiver aspect of defendant’s remote-control system did for a while try to develop something original. ■Shortly before Christmas of 1956, however, Admiral’s management demanded that a completed remote-control system be ready for production without delay, and Admiral’s director of engineering ordered his staff to make a straight copy of Zenith’s Space Command receiver. This order was carried out, even to the extent of copying the minute details of Zenith’s receiver circuit. The story is best told by Admiral’s own employees .and former employees in the depositions offered in evidence in the case. Mr. De-Cola, Admiral’s chief engineer at the time of the Admiral Son-R development, when asked about copying the Zenith product said: “There is no other way out of it.” The testimony of another witness, Holpuch, was to the effect that DeCola as chief engineer advised him to go ahead and use the circuit described in Adler’s ’025 patent. 69. By thus copying both the transmitter and receiver aspects of Zenith’s remote-control system, Admiral was able, by June 1957, to produce and market television receivers equipped with an ultrasonic remote-control called “Son-R”. This system is a direct copy of Space Command. It was vigorously promoted by Admiral and is acknowledged by Admiral to have contributed impressively to its television sales in recent years. 70. During the period since the initial ■introduction of Admiral’s Son-R system in mid-1957, Admiral has from time to time brought out new models. In some respects the new-model romote-eontrol receivers have been less nearly identical to Space Command than were the original Son-R receivers, although the novel circuit features of Zenith’s receivers have still been utilized and many specific circuit details of the Space Command receiver still copied. However, it was stipulated at the trial, and the Court finds, that defendant’s current 1960 model receiver circuit does not infringe plaintiff’s Patent No. 2,817,025. 71. The prog