in form to cover the lock separately, the lock alone is wholly without function or utility, and not patentable as a separate thing; that it is useful only when associated with the peculiar form of the coupler head and knuckle shown in the patent; that such claims must be so read and construed as to embody such other necessary parts of the coupler; and that, when so read, the lock is but an element of a complete combination, and may be repaired by the owner and user of the complete device, so long as the identity of the original device was preserved. The other defense is invalidity, because: (1) Patents were anticipated by prior patents; and (2) that such locking features lack patentable novelty, and are faulty and inoperative.

As the validity of the patents, particularly the claims relied on, must be passed upon regardless of the question whether the parts supplied come under the head of repairs, this question will be first considered. Complainant contends that its lock was the first to give, in a single piece, the function of the "anti-creep" or "lock to the lock," in addition to locking, unlocking, knuckle throwing, and lock-setting; and that the latter functions were performed in a new and desirable way. Tower, in his specification of patent No. 728,049 (basic patent), states the object of his invention and describes its several parts, their operation and functions, and novel features and advantage of his device, as follows:

"The object of my invention is to provide a coupler with a locking and opening piece of simpler construction and easier of operation than heretofore and which will enable the coupler to be made of great strength in proportion to the weight of the metal used therein. These characteristics which I obtain by my invention are of the greatest practical importance, for the reason that the couplers when in use are subjected to severe strains and often to careless use. Safety and certainty of operation require them to be easily operated and to have as few parts as possible.

"In the drawings, 2 represents the coupler head, and 3 is the knuckle, whose tail, 3', extends rearwardly from the pivot-pin, 4, the front side of the tail or the end portion thereof being preferably approximately parallel with the central line of the drawbar when the knuckle is locked.

"The locking and opening piece, 5, in so far as its locking function is concerned, is in the nature of a pin, which extends on the front side of the tail of the knuckle and in locking has a bearing against the coupler head extended both above and below the knuckle. At its lower end is a guiding portion, b, which is inclined forwardly and is adapted to fit in a correspondingly-inclined hole, 6, in the floor of the coupler. Its upper end or head has a forward projection, c, or is otherwise suitably shaped for pivotal attachment to a lifting link, 7, and at the rear of the head is a bearing, d, which is adapted to engage a fulcrum, 8, at the top of the recess, 9, of the coupler head, in which the piece 5 is set. This recess is preferably nearly of the same width as the piece 5, so that it may guide and steady the latter. At the lower part of the recess, 9, is a shoulder, 10, which is adapted to receive the forward portion of the head of the piece 5 when it is in its locked position.

"The operation is as follows: The parts being in the position shown at the coupler B in Fig. 2, the knuckle is closed, and the locking and opening piece fits in front of it, with its guiding portion, b, in the hole, 6. The knuckle is thus held locked. If it be desired to unlock the knuckle and to swing it open, the operator lifts the link, 7, thus causing the locking and opening piece to rise. During its first motion the guiding portion, b, at its lower end, causes it to move rearwardly until it reaches the position indicated by the dotted lines, e, when it has passed back of the path of the tail of the knuckle and has left the latter free to swing open and its head has engaged the fulcrum, 8, at the top of the coupler head. This fulcrum, 8, is inclined or

beveled laterally, as shown in Fig. 4, so that, when the piece bears thereon. it will tip laterally in a direction transverse to the length of the coupler head to a sufficient extent to bring the locking and opening piece somewhat to the rear of the tail of the knuckle, as shown by dotted lines, e, in Fig. 3 and by full lines in Fig. 4. The effect of this is to bring the piece 5 into knuckle-throwing position and also to free it from the path of stop 12, which is formed on the coupler head and is adapted to prevent throwing of the piece 5 until it is at the back of the knuckle. Continued lifting of the link. 7, will cause the piece 5 to tip forwardly on the fulcrum, 8, and to move the knuckle into open position, as shown by full lines at the coupler A of Fig. 3 and by dotted lines at the coupler B of Fig. 2. The operator, having thus opened the knuckle, can allow the locking and opening piece to drop, whereupon it will be restored to the position shown by full lines on the coupler B of Fig. 2. When the knuckle is next swung into closed position, its tail will engage the shank of the piece 5 and, pushing it rearwardly, its guiding portion b will cause it to rise and to move backwardly sufficiently to allow the tail of the knuckle to pass, whereupon it will drop again into the hole. 6, and will hold the knuckle in locked position.

"If it be desired to lift the piece 5 only far enough to unlock the knuckle without throwing it open and to leave the piece 5 in lock-set position, so that the knuckle can be moved open freely when the car to which it is attached is moved away from another car with which it is coupled, the operator simply lifts the piece 5 into the position shown by dotted lines e of the coupler B of Fig. 2 and the full lines in the coupler A of said figure, whereupon the inclination of the fulcrum, 8, as above explained, will cause the piece 5 to move laterally to a small extent. On releasing the lifting link the piece 5 will bear against the end of the tail of the knuckle, as shown in the coupler A of Fig. 2, and will be held against it by friction. There is, however, no locking engagement of the piece 5 with the coupler head, and the knuckle is free to move open when the cars are drawn apart.

"The floor of the coupler head is preferably provided with a longitudinal groove, h, in which the lower end of the piece 5 may rest and which serves to guide it into locked position when the knuckle is moved back.

"In Figs. 6 and 7, I show a modified construction of my invention, in which the lateral beveling of the fulcrum, 8, or other means for causing the piece 5 to move laterally, is rendered unnecessary by extending the end portion, b, of the piece 5 so that it shall have a lateral projection, f, which when the piece 5 is tipped forwardly after engagement with the fulcrum, 8. will engage the end of the tail of the knuckle and will start it on its outward motion and will thus constitute the means for imparting the initial engagement of the locking and opening member with the knuckle. In Fig. 7 I also show the shoulder, 10, provided with a recess or notch, 11, into which the forward portion of the head of the piece 5 can fit when it is in locked position, at which time it will prevent upward creeping of the piece 5, for any tendency to such creeping will simply cause the forward portion of the head to bear more firmly within the recess. At the same time, the recess presents no obstacle to the lifting of the piece 5 by the lifting-link.

"The forwardly-inclined guiding portion, b, of the piece 5, is desirable not only in performing the functions above stated, but also in preventing the tendency of the piece 5 to creep upwardly. It acts in this way singly and also in co-operation with the recess, 11, when the latter is employed.

"One of the important and novel features of my coupler consists in the use of a locking and opening piece whose locking and opening member in locking fits in front of and locks the tail of the knuckle and when raised first frees and then by a continued movement opens the knuckle, the successive operations being functions of the same member, which preferably is also arranged to have the capacity of setting itself in unlocked position while the knuckle is still closed. The main member of the lock, therefore, has three functions, and the same part which locks the tail of the knuckle also operates to throw it open and, if desired, sets itself in unlocked position when the knuckle is still closed. The simplification of construction and strength which I thus secure will be appreciated by those skilled in the art.

It is conceded that this locking and opening device has three functions: That of locking or coupling automatically, of setting the lock piece in an unlocked position, and of throwing or kicking the knuckle into a complete open position. The second patent, No. 728,182, is an improvement on the coupler shown and described in the former patent. These improvements, so far as the locking piece and attachment are concerned, consist in a changed configuration of the lock

"I obtain a large locking surface of the piece 5 against the tail of the knuckle and against the coupler head. I can also employ a knuckle tail sufficiently long to prevent jamming of the knuckle when two couplers are brought together each with the knuckle in open position. Such jamming is likely to occur in some couplers heretofore in use."

The following are the drawings referred to:

piece and the addition of two separated projections on the front of the shank or locking part of the lock, and a stop device on its link connection to support the connecting link in upright position. Figs. 2, 4, and 5 of this patent are here inserted to show these changes and the coacting parts of the knuckle tail and interior contour of the coupler recess:

The general features and functions of this lock are the same as that of the earlier patent. Its special added features, adopting the language of complainant's brief, are as follows:

"On the middle forward surface of the lock shank are two projections, h and g, having a space between them which allows the lock to be inserted in the coupler cavity through the mouth of the coupler. These projections are adapted to perform the function of tipping off the lock from the lock-set position and of driving it rearwardly when the knuckle is closed. Thus, the knuckle tail strikes the lower projection, g, in pulling the knuckle open from lock-set position, while in closing, when the lock is resting on the floor of the coupler, it will strike first the projection g, and then the projection h, lift the lock and drive it rearwardly until it drops to locked position with the knuckle closed. If the lock is in lowermost position when the operation of closing the knuckle begins, the knuckle tail will first strike the upper projection, h, and then the lower projection, g, lifting and driving the lock rearwardly and upwardly out of the path of the knuckle tail, so that, when the knuckle has been closed, it will drop back to the locked or lowermost position.

"In the top of the lock is a slot in which the lifting link, 7, is pivoted, and in the rear of this slot is a stop shoulder, m, which act to keep the link, 7, upright and to prevent its falling backward and wedging in the recess, 9, of the coupler head. This stop shoulder supports the link when the lock is in locked position, so that when the chain is operated the link is guided through the hole in the top of the coupler head."

The essential characteristics of the locks of the two patents are summed up by complainant's expert, Mr. Bently (Rec. p. 304), as follows: "I find that in both of these patents there is a coupler having the same fundamental qualities, to wit, a locking piece characterized, as to form, by a forwardly-inclined toe at its lower end and a fulcrum and lifting-link attachment at its upper end, and characterized, as to operation, by a preliminary rearward swing produced by the cam action of the toe-hole upon the toe serving to release the knuckle tail and followed by a forward knuckle-opening swing produced by the lever action of the locking piece on its fulcrum; this to and fro swing of the lower end of the locking piece being produced by a continuous upward movement of the upper end of the piece by the pull of the lifting-link. I find that the device of the later improvement patent differs from that of the earlier patent in that the knuckle tail of the latter acts directly upon the curved shank of the locking piece, whereas in the improvement patent it acts upon two distinct lugs or projections on the front side of the locking piece; its engagement with the upper projection being on the under side of that projection and serving to lift the locking piece and free it, so that it hangs nicely balanced and easily pushed rearwardly by the engagement of the knuckle tail with the lower projection. In addition, the locking piece of the improvement patent is provided with a back-stop for the lifting-link, which serves to guide it through the operating hole in the top of the coupler head."

The functions of locking automatically and lock-setting and knuckle throwing were old when the Tower patents were applied for. Step by step the art had advanced; the field of invention constantly narrowing. Many and varied were the patented devices by which all three of such functions were performed; nor was it new to perform all these functions with a single piece or lock.

Defendant cites a number of patents as anticipations and as showing the state of the art. As to the lock as shown in patent No. 728,049: