Cadillac Motor Car Co. v. Austin

• Decision Date: 30 June 1915
• Docket Number: 2766.
• Parties: CADILLAC MOTOR CAR CO. et al. v. AUSTIN.
• Court: U.S. Court of Appeals — Sixth Circuit

225 F. 983

CADILLAC MOTOR CAR CO. et al. v. AUSTIN.

No. 2766.

United States Court of Appeals, Sixth Circuit.

June 30, 1915

Infringement suit by Austin against the Cadillac Company, based upon claims 9, 10, 11, and 12, of patent No. 1,091,618 for 'change-speed gearing,' issued to Austin March 31 1914, on application filed August 12, 1913, in renewal of application filed February 16, 1911. From the usual interlocutory decree for injunction and accounting, the Cadillac Company appeals.

The specification classifies the invention as relating to change-speed gearing, 'especially adapted to automobiles.' In the common form of this machine, the engine crank shaft, running longitudinally of the car, is clutch-connected to a propeller shaft, extending back in the same axial line into bevelgear engagement with the rear axle which is thus driven, and which drives the car. In the simplest form of clutch connection between engine shaft and propeller shaft, the two must always revolve at the same speed. In transmitting the power from the propeller shaft to the axle through the bevel gearing, it is obvious that the relative speeds of driving shaft and driven axle can be determined by adopting any desired ratio between the number of teeth on the driving shaft-carried pinion as compared with the number on the driven axle-carried gear. To illustrate: It may be assumed that, for ordinary speed on average roads, the best ratio is 3 to 1-- that is, three times as many teeth upon the axle gear as upon the shaft pinion-- and it will follow that for each shaft revolution the wheels will make one-third of a revolution. It is clear that no such permanent or fixed relation, 'direct drive,' between engine speed and axle speed will meet the varying conditions of service; and so it has been common to interrupt the propeller shaft by interposing between its front and rear severed portions selective transmission devices, whereby the relation between the speeds of engine and of propeller shaft may be varied. A short parallel countershaft, carrying gears of different sizes corresponding gears upon the propeller shaft, and means for sliding some of these gears longitudinally, or, perhaps for using none of them and clutching the two parts of the shaft directly to each other, enable the operator to select the ratio which he prefers; and if, for example, he selects a ratio of 4 to 1 in his transmission, and has a ratio of 3 to 1 in his direct drive, he will have an effective final ratio of 12 to 1, as between his engine and his driven axle, resulting in the so-called 'low speed.' It is obvious, too, that this indirect method of transmission, by breaking the continuity of the propeller shaft and interposing gearing, is less desirable than if the driving power comes directly from engine to axle, and so it is commonly understood that the direct drive or the 'high speed' is to be preferred wherever conditions permit. It was Austin's idea to increase the flexibility of this direct drive by providing alternative gear pairs between shaft and axle and by providing selective mechanism, whereby the driver can cause one of two driving pinions on his shaft to drive either one of two beveled gears upon the axle, whereby, for example, the driver may shift the connection from one to the other and change the gear ratio from 3 to 1 to 2 to 1, so causing a complete revolution of the wheels to each two revolutions of the engine shaft, and increasing the speed of the car 50 per cent. without changing the speed of the engine. The very considerable practical advantages of this result are conceded, although there are disadvantages, and the ultimate balance will not necessarily and always be favorable. Such favorable net result, which will make the idea practically worth while, was to be attained only by exercising either a high degree of skill or a considerable amount of invention, as the two may be classified, in minimizing the bad and emphasizing the good among the attendant conditions.

What Austin did was to provide, at the rear end of his propeller shaft, a small bevel pinion fixed thereon and to carry just forward thereof another and larger bevel pinion fixed to a sleeve surrounding the driving shaft. In front of this sleeve the shaft carried a longitudinally sliding clutch, splined upon and always revolving with the shaft, but capable of being engaged with or disengaged from the pinion-carrying sleeve. It resulted that while the smaller pinion would always revolve with the shaft, the larger one would or would not, according as it was clutched thereto or unclutched therefrom. These two pinions were always in mesh with the corresponding bevel gears on the differential housing (thus ultimately revolving the axle), the forward pinion and the outside gear having the high, or 2 to 1, ratio, and the rear pinion and the inside gear having the low, or 3 to 1, ratio. Since it is clear that both gear pairs could not be clutched to and fast upon shaft and axle, respectively, at the same time without stripping some of the gears, and since when Austin's clutch pinion was fast to the shaft, both pinions thereon must revolve, he made the inner or low-speed gear loose upon the axle, and provided a clutch sliding longitudinally on the axle and always revolving therewith, but engaging the inner gear to the axle only when desired. He then connected his clutch on the shaft and his clutch on the axle by toggle levers so that they automatically acted together, and when one was thrown in, the other was thereby necessarily thrown out. It followed that if the forward pinion on the shaft was made fast thereto, it would drive the outer gear and so drive the axle, but while the rear pinion would also drive the inner gear, the latter would be free from the axle and would run idle thereon. If the forward pinion was unclutched from the shaft, the inner gear would be driven by the rear pinion, and the inner gear being then fast to the axle, it would cause the outer gear also to revolve, this, in turn, would drive the forward pinion, and the latter, being free from the shaft, would run idle thereon. It therefore resulted that, of the four gear members, three were always fast and one always idle.

The defendant's device employes the same two gear pairs; that is, two driving pinions on a propeller shaft, and two driven gears upon the axle. ' The four gear members have the same relative form, size, mounting, and arrangement as in Austin's, in all particulars except one; the smaller and rear (being the low-speed) driving pinion, instead of being fixed on the propeller shaft, is carried upon a sleeve concentric therewith, and which may be clutched thereto, and the other member of the pair, the inner or low-speed driven gear, is fixed to the axle instead of being clutch-connected thereto. In other words, the high-speed gear pair is wholly the same in both machines and the low-speed gear pair is the same, excepting that the capacity of being detached from its shaft is transposed from one member to the other. Of the four gear members, three are always fast and active, one always loose and idle.

The case presents the questions whether the claims in suit can properly be so read as to cover defendant's device, and, if so, whether they are valid. Claim 10 may fairly be considered typical of the group sued upon, and it reads as follows: 'In a change-speed gearing for automobiles, the combination of the axle, differential gearing, and a suitable housing, an outer driven beveled gear secured to said housing and an inner driven beveled gear nested with the outer beveled gear, either one or the other of which is adapted to be connected to drive the differential gearing structure to operate the said axle, a propeller shaft, a bearing for the inner end thereof, an inner pinion thereon adapted to mesh with the inner driven beveled gear, and an outer pinion concentric therewith adapted to mesh with the outer beveled gear, the outer gear and pinion being of higher ratio than the inner gear and pinion, and means for coupling either the outer beveled gear and pinion, or the inner beveled gear and pinion to said propeller shaft to drive the said axle, co-operating for the purpose specified.'

F. P. Fish, of Boston, Mass., for appellants.

F. L. Chappell, of Kalamazoo, Mich., for appellee.

Before WARRINGTON, KNAPPEN, and DENISON, Circuit Judges.

DENISON Circuit Judge (after stating the facts as above).

1. Defendant insists that whatever invention Austin made extended only to the relative arrangement of his clutched and fixed gear members, and hence that his patent must be confined to a device carrying one clutched driving pinion and one clutched driven gear, with connections whereby the two clutches have an in and out automatic action. We cannot so interpret claim 10. Its language is not incapable of such a limitation, when it is read in connection with the specification; but when we compare the various claims, including those not in suit, we find that this particular clutch construction and arrangement are expressly specified in, and seem to be the dominant thought of, another group of claims, while not mentioned in the group of claims in suit. This comparison clearly shows that the latter were intended to be distinguished and characterized by the provision that the outer gear and pinion were of higher ratio than the inner gear and pinion.

It follows that, under the familiar rule which we have several times followed and applied (Scaife v. Falls City Co., 209 F. 210, 214, 126 C.C.A. 304; National Co v. Mark, 216 F. 507, 521, 133 C.C.A. 13), we will not read into one claim elements which expressly characterize another, by which alone the two substantially differ and which are not necessary to make the former operative; and...