Appeal from the District Court of the United States for the Eastern District of New York.
Before MANTON, SWAN, and CHASE, Circuit Judges.
The patents sued on, to Kennington No. 1,527,588, granted February 24, 1925, for gearing for starting internal combustion engines, and to Bergmann No. 1,254,196, granted January 22, 1918, for automatic clutching or starting device, were held invalid.
The patent to Kennington was held invalid in view of the prior invention by Bendix, Vogtland, and Bijur. This patent is for an automobile engine starter of the mesh and demesh type with spring means to cushion the shock of the starting engine. The appellant says it was a continuation in part of a joint application filed May 25, 1912, by McDermott and Kennington. Claims 10, 11, and 12 are sued on.
This patent, referring to a starting motor, drives an externally threaded shaft upon which is mounted an internally threaded pinion. Upon rotation of the threaded shaft, the pinion moves longitudinally into engagement with a gear operatively connected with the crank shaft of the engine. After the pinion has moved into engagement with the engine gear, its longitudinal movement is arrested by a spring stop on the threaded shaft. The pinion then rotates with the shaft, and, being in mesh with the engine gear, drives the engine. When the engine starts, the pinion, being driven more rapidly by the engine than it is by the threaded shaft, is moved backward along the shaft until it is out of mesh with the engine gear.
The starter developed by Bijur, disclosed in the patent No. 1,095,696 (application filed March 13, 1912; two months prior to McDermott and Kennington, application of May 25, 1912), is for a motor which drives a threaded shaft through reduction gears. An internally threaded pinion is mounted on the threaded shaft, and at the end of the shaft there is a fixed stop which arrests the longitudinal movement of the pinion after the pinion has moved into engagement with the gear on the engine flywheel. The Kennington application was placed in interference with this patent in the Patent Office with respect to claims broadly covering a starter of the automatic mesh and demesh type. The interference terminated July 19, 1916, in favor of Bijur. Necessarily, further prosecution of the Kennington application was limited to additions claimed to have been made to a transmission of the automatic mesh and demesh type, and this included principally a type of spring; other minor features are not here involved. The difference between Bijur and Kennington lies in the substitution of the spring stop for Bijur's fixed stop.
In the automatic mesh and demesh starter, considerable strain is placed on the whole structure when the rotating motor is suddenly coupled to the stationary engine through the pinion and the threaded shaft. It is desirable to provide some means for reducing the shock which occurs when the rotating starter motor is coupled to the engine. It was well known that a spring could be practically used for reducing shock and strain in a train of gearing. It is with such knowledge that Bendix, Bijur, and Kennington resorted to this expedient.
Kennington in his patent discloses the use of a compression type spring placed at the end of the threaded shaft. It is described in the patent as serving as a spring buffer to gradually stop the outward movement of the pinion. The spring has two functions, first, to act as a buffer to arrest the longitudinal movement of the pinion, and, second, to cushion the shock due to the strain of starting the engine. The claims involving the spring continued in the application from the time it was filed in 1915 until 1922 and were limited to means for performing both of these functions. After 1922, claims, directed broadly to the function of the yielding drive and not limited to the buffer type spring, were inserted. These are claims 10, 11, and 12 in suit. Claim 10 calls for "means automatically yielding in conformity with the resistance of the engine member to rotation for gradually building up torque to overcome said resistance." Claim 11 specifies "means prolonging the period during which initial torque is built up to include time subsequent to the establishment of the driving relation." Claim 12 is for "means for building up the torque beyond the normal torque of the starting means."
When the rotating starting motor and the shaft are coupled to the engine flywheel, the inertia of the engine acts as a brake on the motor, decelerating the motor. Deceleration torque is a force arising from momentum of the motor which opposes this deceleration and acts to overcome the opposition of the engine to the rotation of the motor. This force is developed in any automatic mesh and demesh type of starter whether the spring is present or not. The addition of a spring or yielding drive serves to reduce the rate of deceleration of the motor and, therefore, the intensity of the deceleration torque.
By the fall of 1913, Bendix had developed the form of a starter which, with some minor refinements, was subsequently adopted by the industry. The appellant became interested in this device and built starters according to Bendix design in January, 1914. Appellant obtained an exclusive license under the then pending application of Bendix and included any subsequent developments made by Bendix in transmissions for automobile starters.
The Bendix patent No. 1,124,264 was directed to the use of a yielding driving connection in a starter of the type here considered and was issued January, 1915. The appellant obtained substantial approval of the industry in the validity of this patent throughout its term which extended until 1932. It proved a commercial success of very high order. The specifications of the Bendix patent read that its object was to provide a "simple and efficient means for preventing shock * * * the means provided for the purpose described consists of a yielding driving connection interposed at some suitable point between the motor and the engine element, but preferably between the screw shaft and its pinion."
The preferred location of the yielding driving connection between the screw shaft and its pinion is the location in which the spring is found in the Kennington patent. In three forms shown by Bendix, the spring performs the function of a compression spring as well as that of a torsion spring. In all three the spring is specifically located between the screw shaft and the pinion and therefore between the motor and the pinion. In another figure, the spring is located between the motor and the screw shaft; it is within the large gear on the screw shaft where it acts only as a torsion spring.
In claim 1 of the Bendix patent, the patentee claims the use of a yielding driving connection in an engine starter. It covers broadly the particular type of compression spring shown in the Kennington patent. This claim is not limited to any particular type of yielding driving connection, and the use of the phrase "interposed between the motor and the driving member" is used in a functional sense to include all the forms shown by Bendix ...