Appeal from the District Court of the United States for the Northern District of Illinois, Eastern Division; John P. Barnes, Judge.
Before SPARKS and MAJOR, Circuit Judges, and LINDLEY, District Judge.
This action sought injunctive relief and an accounting for alleged infringement of United States patents to Brenne, No. 1,555,628, and to Johnson, No. 1,730,214. The former was issued September 29, 1925, on an application filed November 2, 1922; the latter was issued October 1, 1929, on an application filed October 25, 1923. Continuously since their issuance appellee has owned all right, title and interest in both patents. They relate to draft gears for railway cars. A draft gear is a device for cushioning certain shocks of train operation, more particularly those incident to the coupling of cars. Its purpose is to furnish a yielding connection between the coupler and the car frame, and it acts as a shock absorber.
Two of appellant's devices were charged with infringement of both patents, and appellant denied validity and infringement as to each. The court found both patents valid; that claim one of the Brenne patent was infringed by appellant's first device only, and that all five claims of the Johnson patent were infringed by both of appellant's devices. Injunction and accounting were awarded and supersedeas accompanied the granting of this appeal.
In shock absorbing mechanisms employing a friction shell, a plurality of friction shoes arranged in a circular series within the shell, and a pressure transmitting member, it was the usual practice to make the shell as a casting without any machine operation, to also make the wedge member as a casting, and to drop-forge the friction shoes. The wedge and shoes could thus be made satisfactorily accurate, the flat or plain wedge faces being easily ground to remove any slight casting irregularities. In the case of the interior of the cylinder, however, machining would be both difficult and too expensive for practical consideration.
In friction devices of the character here involved, it is essential to desired efficiency that true full contact be had on all co-operating friction surfaces and also on the wedge faces. Due to the necessary foundry variations which must be permitted in commercial practice it was known that proper contact of all the sets of friction surfaces could not always positively be insured, and as a result thereof the devices did not function with the greatest efficiency.
Appellant's first device was completed and tested in July, 1934. On August 1, 1934, appellee notified appellant of the Brenne patent and of appellant's infringement of it. Thereupon, and before this action was instituted, appellant modified and discontinued its first device. As to the Brenne patent, therefore, appellant has no interest except for the decree for an accounting, which of course involves its validity and appellant's infringement thereof by its first device.
Following the order adopted by both parties we shall consider the Johnson patent first. Its objects are said to be: (1) To provide a simple expedient, not involving increased cost of manufacture, by which adjustment of the parts, within the limits of variations necessitated by commercial manufacture, can be had to positively insure the proper contact of all the co-operating engaging set of faces; (2) to provide means for insuring flat surface contact between the pressure-transmitting wedge and the co-operating faces of the shoes, while allowing for those variations necessitated by commercial practice; (3) to provide a process or method by which the contacting faces of the wedge and the shoes will be brought into true flat surface engagements with each other by a very few actuations after assembly, whereby the permitted foundry variations in commercial practice will be compensated for.
The patented mechanism is attached to the usual draft or center sills of a car under-frame, to the inner faces of which sills are secured front and rear stop lugs. The draw bar is operatively associated with a hooded cast yoke of well-known form, within which is disposed the patented mechanism with front and rear main followers. The mechanism proper is of that type which employs a substantially cylindrical shell and cage which is held in proper central position by guide plates secured to the draft sills, the yoke parts therein being supported in operative position by a detachable saddle. The shock absorbing mechanism comprises a combined friction shell and spring cage casting; a pressure transmitting wedge; three friction shoes; a spring resistance; a spring follower; and a retainer bolt. The shell and spring cage casting is of generally cylindrical form having the friction shell proper open at its front end. The rear of the casting constitutes the cylindrical spring cage, and at its rear the casting has an integral transverse wall bearing on the rear follower. The friction shell proper is preferably of the following formation: The interior of the shell, while of generally cylindrical contour, is preferably comprised of three true cylindrical surfaces, symmetrically arranged around the axis, and of approximately 120 degrees extent each. These cylindrical surfaces are converged inwardly of the shell on a relatively slight taper and in such a manner that the inner ends of the three cylindrical surfaces merge into a true circle. With this arrangement, the friction shoes, which have cylindrical surfaces, will maintain true surface contact, as distinguished from line contact, with the shell at all positions during a compression stroke.
The wedge through which the pressure is transmitted is in the form of a hollow casting, having a front tranverse bearing face engaging the front follower. At its inner end the wedge is provided with a true wedge face and two other rearwardly converging inclined faces, all of which are disposed around the center or axis of the wedge, so as to give the wedge the appearance of a truncated, somewhat irregular triangular, pyramid. The wedging surfaces of the friction shoes and the wedge are not all true wedge surfaces, there being one pair of such contacting surfaces more acute than the other two.
Two of the friction shoes, referred to as C and E, are alike, each having an outer friction surface which corresponds to a portion of a true cylindrical surface and which extends through an arc of approximately 120 degrees. On the side nearest the axis of the shell each of the said shoes has a lateral enlargement on the front side of which is provided a rearwardly and inwardly inclined, longitudinally convex face, co-operating with one of the inclined faces of the wedge. The third shoe, referred to as D, is provided with a similar outer cylindrical friction surface, and on its inner side with an inwardly projecting enlargement having an inclined, longitudinally convex wedge face coacting with the other true wedge face. The faces of the shoes are so disposed that the front ends of the shoes will normally lie approximately flush with each other and project a short distance outside the end of the shell. The faces of the shoes are only slightly convex, being curved longitudinally on an arc of relatively great radius.
The spring resistance comprises an outer heavy coil, bearing at its inner end against the rear transverse wall, and an inner coil, bearing at its inner end upon a hollow cup-like boss formed integral with the rear transverse wall. The spring follower is more or less cup-shaped, having a heavy annular flange, the inner side of which is adapted to bear the front end of the outer coil. This spring follower has a forwardly extended integral cup, the interior of which provides a bearing for the front end of the inner coil.
The retainer bolt is anchored at its rear end within the cup-like boss above referred to, and its forward end within a recess in the front end of the wedge. This bolt not only serves to maintain the assembled parts, but is also used to adjust the parts to proper overall length, to thus maintain them when under full ...