Reporter's Statement of the Case British Government and as sent to the Marlin Rockwell plant is diagrammatically illustrated in the accompanying drawing: Constantinesco Hydraulic Synchronizer (as in original sample furnished to Vickers Machine Gun P ·D E A The mechanism comprises a generator unit A which functions by means of an engine-driven cam to generate suitably timed pressure impulses upon oil contained in a tubular conduit B connected to a trigger motor C; the oil system is kept under pressure by a hand pump E, and a suitable bypass F is controlled by mechanism D in such manner that transmission of the impulses to the trigger motor and the consequent operation of the firing of the gun are under the control of the pilot or gunner. When the control mecha Reporter's Statement of the Case nism D is operated so as to permit the impulses to be transmitted from the generator to the trigger motor plunger G, this plunger moves forward on each impulse and rotates the lever H, which lever is connected at its top with trigger bar K. The trigger bar K is in engagement at its forward end with the sear L. When the trigger motor plunger G therefore moves forward under an impulse it operates the lever H and trigger bar K to rotate or reciprocate the sear L about its pivot, thus releasing the cocking lever M which in turn releases the firing pin O which moves forward and fires the cartridge. When the breech bolt is in its firing or locked position the trigger bar K is in engagement with the sear L; consequently if the trigger motor C receives an impulse when the breech block is not in breeched position, the trigger bar K is retracted and merely idles and does not cause any action of the gun. In addition the firing pin O is engaged by a safety sear P which serves to restrain it from moving forward until the breech bolt is in the breeched or firing position. Any impulse received by the trigger bar K prior to the breech bolt assuming the breeched position or firing position therefore does not cause the gun to operate, but any impulse received by the trigger motor C subsequently to the breech bolt assuming its firing position will cause the gun to fire. The highest rate of fire of the Vickers synchronized aircraft machine gun was 850 to 900 shots per minute. 8. September 27, 1917, the Ordnance Department entered into a contract with the Marlin Rockwell Corporation for the manufacture of 23,000 Marlin aircraft machine guns, conditioned upon the Marlin machine gun being first made suitable for synchronized fire from aircraft in connection with the C. C. gear. March 21, 1918, the Ordnance Department made a contract with the Marlin Rockwell Corporation for the manufacture of an additional quantity of 15,000 Marlin aircraft machine guns. The so-called Marlin gun was developed at the plant of the Marlin Rockwell Corporation and was intended for temporary use until the Browning machine gun, which was then being developed by Reporter's Statement of the Case John M. Browning, could be made ready for quantity production. 9. In February 1918 John M. Browning completed the development of a machine gun for ground use which became known as the Browning machine gun. This gun was developed at Hartford, Connecticut. This gun, as originally constructed for ground use, had a rate of fire of 350 shots per minute. In order to make it suitable for aircraft use, Browning speeded up the rate of fire to 1,200 shots per minute by the addition of a muzzle attachment to increase the recoil energy of the barrel, lightening of the breech bolt, lessening of the firing pin fall, and increasing the strength of certain springs. On or before March 1, 1918, sample guns of this type were delivered to the experimental shops of the Marlin Rockwell Corporation at Liberty Field, New Haven, Connecticut, for the purpose of adapting the Browning gun to synchronized fire from aircraft. 10. The Browning machine gun of the ground type was a recoil-operated gun. When the gun was fired the energy of the recoil caused the barrel, the barrel extension, and the bolt which were locked together to move to the rear. This rearward movement caused the feeding mechanism to feed a loaded cartridge into position after extracting the empty cartridge. While the breech bolt was moving to the rear the upper end of the cocking lever which was pivoted in the breech bolt engaged in the receiver of the gun in such manner as to cause the lower end of the cocking lever which engaged the firing pin to move the same into firing position where it was engaged and held by the sear. The energy stored in the recoil spring then caused the breech bolt to move forward into the firing position. During this forward movement the firing pin was retained in its rear position by the sear and was capable of release only when the sear was operated by the trigger bar. The trigger bar was pivoted to the receiver end; its rear end had a trigger shape while its front end had a 45-degree cam which engaged a similar shaped cam at the bottom of the sear. This engagement of the trigger bar and the sear took place only when the breech mechanism was in the Reporter's Statement of the Case firing position. If at that time the trigger was operated, the sear mechanism was released which in turn released the firing pin which moved forward and fired the cartridge. The sear was of the vertical sliding type. 11. In order to adapt the Browning gun for synchronized aircraft fire, it was necessary to convert the gun from a full automatic gun to a "single shot" or a semi-automatic gun, i. e., instead of allowing the gun to continue firing as long as the trigger mechanism was depressed, it was desirable to operate the trigger mechanism for each shot. The feed way and the feeding mechanism had to be changed in order to make it suitable for a disintegrating steel cartridge belt, which is used on aircraft guns, instead of a woven fabric belt, which is used on ground guns; and it was necessary to make modifications in the firing mechanism to permit the attachment of synchronizing gears so as to transmit the action of the synchronized trigger motor to the sear of the gun. 12. The various alterations in the structure of the Browning machine gun necessary to adapt it for synchronized aircraft fire were the result of the work and collaboration of Lieutenant Wheeler, Captain Craft, Mr. Browning, Hugh Rockwell, and Carl Swebilius. Lieutenant Wheeler was stationed at the experimental laboratory of the Marlin Rockwell Corporation at Liberty Field, New Haven, Connecticut, during February, March, and April of 1918. His work in connection with the Browning gun was supervisory in character but in addition he performed a considerable amount of the actual work himself and made the firing tests. Lieutenant Wheeler's superior officer was Captain Craft, who during this period visited the laboratory every two or three weeks, staying a week or longer at each visit. Hugh Rockwell was an officer of the Marlin Rockwell Corporation. Carl G. Swebilius was, during the time of the war, employed by the Marlin Rockwell Corporation to make up experimental models. He was stationed at the plant of the Marlin Rockwell Corporation, of New Haven, receiving instructions from the experimental shop at Liberty Field. 78975-37-cc-vol. 83 Reporter's Statement of the Case His contract of employment with the Marlin Rockwell Corporation required him to assign to it patents covering any improvements or inventions devised by him while in its employment. Swebilius saw the Vickers aircraft machine gun with the Constantinesco synchronizing gear attached thereto when it was first delivered at the plant of the Marlin Rockwell Corporation. He examined the gun in detail and its operation was explained to him by ordnance officers stationed at the plant. 13. There is no satisfactory evidence as to what individual contributions were made by the various persons mentioned in finding 12 relative to the changes in structure necessary for adaptation of the Browning machine gun to synchronized aircraft fire. Lieutenant Wheeler, who had charge of the matter in a supervisory capacity, lost his life during the war, and Captain Craft, the only member of the group who testified, was not present at all of the various conferences which took place between the members of the group and did not know who suggested making the connection of the synchronizing gear to the gun from the side. Insofar as the patent in suit is concerned Swebilius had the assistance of numerous United States Army officers in the development of the device covered by the patent, together with material, blueprints, designs, and experimental data of the Ordnance Department, all of which was placed at his disposal. There is no satisfactory evidence that the assistance and collaboration which Swebilius received from his associates differed in degree or character from that which would be given by the ordinary mechanic skilled in this art. 14. In adapting the Browning machine gun to synchronized fire for aircraft, the hydraulic trigger motor of the Constantinesco synchronizing gear was mounted on the rear of a housing, which housing was arranged for attachment to the side of the receiver of the Browning gun. At the front end of the housing a triangular trigger member was mounted having one portion adapted to function as a cam against which the trigger motor bears, and having a second |