The opinion of the court was delivered by: SCHOONMAKER
This is a patent-suit charging defendants with infringement of Mottlau patent No. 2,089,807, issued to plaintiff August 10, 1937, on an application filed March 16, 1932. This patent relates to a free-wheeling clutch for an automobile. The title of the plaintiff to this patent and the jurisdiction of this court are conceded; they otherwise appear by the proofs.
The defenses are: (1) Non-infringement; (2) invalidity, because the device is inoperative; (3) estoppel to assert any broad construction of the claims in suit, because of the rejection and cancellation of such broad claims in the Patent Office; and (4) invalidity, because plaintiff is attempting to repatent an old combination in which merely one element only has detailed features which may distinguish it over the prior art.
A large number of the claims of this patent were sued upon; but at the trial, plaintiff restricted his charge of infringement to claims 25, 28, 38, and 39. In his request for conclusions of law, plaintiff restricted his charge of infringment to claims 38 and 39. These two claims read as follows:
"38. In an automotive vehicle, the combination with a drive shaft; a driven shaft; and a uni-directional clutch between the two shafts and operative throughout the normal driving speed range of the drive shaft to connect and to disconnect the two shafts; of means operative at the will of the vehicle operator to render the clutch non-effective, said means including relatively movable co-operative parts respectively mechanically connected to each of the shafts and operative to connect the two shafts to establish a driving connection to by-pass the uni-directional clutch, said cooperating parts being effective radially to clutch and to declutch and being relatively rotatably movable within the clutching zone; and means responsive to a synchronous relation between the relatively moving co-operating parts of said by-passing connecting means for controlling the connection of said relatively moving parts.
"39. In combination in an automotive vehicle, a drive shaft; a driven shaft; self-releasing means for connecting the two shafts throughout the normal driving speed range of the drive shaft; second connecting means operative to bridge the selfreleasing means and to connect the two shafts to transmit energy between them, said second means including a first clutch element connected to one shaft, a second clutch element connected to the other shaft and radially operative to clutch the first clutch element, said second clutch element embodying a clutching portion and a portion serving as a yielding support therefor; and automatic means responsive to the relative speeds of two cooperative parts of the bridging connecting means for controling the completion of the connection of the bridging means."
The plaintiff admits that the elements of these claims are individually old, but contends that the combination of these old elements, as shown by the patent in suit, produces a cooperative functional relationship to accomplish a new and useful result; i.e., the driver is able to change from free-wheeling drive to positive drive while driving, the actual change-over occurring at synchronism, under control of a synchronism detector, without further attention from the driver after he has initiated the change-over.
It does not appear that any cars in actual use have ever been equipped with the Mottlau free-wheeling-clutch combination. We are dealing here with a paper-patent, the utility of which has never been demonstrated in actual driving experience. In such a case, the patent must be construed strictly, and cannot be considered as a pioneer invention entitled to a large range of equivalents.
The ordinary normal automobile-drive arrangement consists of the engine, which, through the interposition of the clutch, the transmission mechanism, the driven shaft, and the universal joint, drives the rear wheels of the car through the instrumentalities of the differential which is mounted on the rear axles. The transmission is usually housed in a single compartment and is operated by a shift-lever, which is used to rearrange the transmission elements, so that there may be three forward speeds and one reverse speed.
The patented structure has these normal elements with an added free-wheeling clutch in the running gear, so constructed that the driver has the choice of driving through a free-wheeling mechanism operable at the will of the driver whenever he wishes to avail himself of the free-wheeling device by pulling a lever, the actual change-over to free wheeling taking place when the operating parts are at synchronism. In the plaintiff's free-wheeling device, we have (1) the free wheel clutch; (2) the by-pass connection for this clutch; and (3) the synchronizer.
The free-wheeling clutch is what is known in the art as a "coil clutch." It consists of a coil-spring, which in operative relationship is squeezed into a drum rigid with the driven shaft.The engine or drive-shaft is fastened to one end of the coil, and the other end of the coil-spring is free. This free end bears against the drum with considerable force, so that when the engine is driving, the friction between the coil and the drum will tend to expand, and in this manner cause the spring to grip the drum with a driving action. When the drum turns faster than the engine or drive-shaft (as is the case when the automobile is coasting), then the coil-spring will contract, and the drum will over-run the spring and free wheel.
The synchronizer is a device by which Mottlau provides to hold the by-pass clutch in released position, despite the setting by the control-rod to engaged position until the drive-shaft is brought to the speed of the driven shaft.
In the defendants' accused structure (exemplified by defendants' Exhibit 6, and by drawings, defendants' Exhibit 11), we have what is known in the automobile art as an overdrive mechanism, which is designed for the purpose of driving the driven shaft of an automobile at a speed which is greater in revolutions per minute than the speed of the drive shaft. This overdrive is secured by planetary gearing, which consists of three elements -- a sun-gear, a ring-gear, and the planetary gear. These are shown on defendants' model, Exhibit 5, the sun-gear being painted blue, the ring-gear, green, and the planetary gear, orange. In operation, the sun-gear is stationary and tied up with the enginedrive shaft, and the planetary pinions rotate about the sun-gear, and at the same time rotate on their own axis, with the result that the planet pinion, at its outer dimension, rotates faster than it does where it engages the sun-gear. The defendants' overdrive unit is a combination of this planetary-gear set, with a pair of radially slidable overdrive dog clutches, a shiftable sleeve, and a roller or one-way clutch.To operate the overdrive mechanism, a shiftable clutch under control of the driver by a lever in the driver's compartment is shifted to its forward or left-hand position. This permits the engagement of the overdrive dogs, which are responsive to centrifugal force at a predetermined carspeed of about thirty-five miles per hour. The driver then releases the gas-throttle to ...