442 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



In transporting gnns, when descending declivities, it is necessary to lock 

 the wheels. This has heretofore usually been done by locking a wheel, 

 which could be done on one side only, by means of a chain attached to the 

 trail. This method tends to rapidly wear out the tire of one wJieel, and 

 requires that the carriage be stopped long enough to lock and again to 

 unlock the wheel, which in rapid movements is sometimes a serious matter, 

 and if a whole column were delayed the evil might be disastrous. I em- 

 ploy a shoe, so peculiarly constructed and attached that it may be dropped 

 in front of either wheel at pleasure, and the wheel caused to run upon it, 

 and to ride down the declivity upon the shoe, and then the latter may be 



^is.> X ' ,^<^, 1 again released from the wheel witli- , — , , — , 



( ^ out stopping the carriage at all. \ . y ^ 



' ^^^^jj^ The left figure is a cross section on ^^ ^^ :=^^r^^ 



the line TT of the trail, and the right figure is a plan view 

 of the shoe and its connection. 



The shoe is made to fit the periphery of either of the wheels. To ears on 

 one side a traverse is fixed, as represented, carrying a ring which is free to 

 slide to either end of the shoe, whereby the shoe is adapted for use under 

 either wheel at pleasure, by simply shifting ends. A chain extends from 

 the ring to a traverse hung beneath the trail, as represented in the right 

 hand cross section of the trail above; this chain being of just sufficient 

 length to allow the shoe to pass under the center of the wheel. The 

 traverse under the trail and the one on the shoe allow the chain and shoe 

 to extend to either wheel as desired, as shown. 



In the chain I make one of the links longer than the rest, and provide a 

 slip-link and ring, so arranged that by sliding the ring off the end of the 

 chain it will be parted, as is obvious from the drawing. Another chain is 

 attached to the two parts in the manner represented, and is of such length 

 that when the toggle is parted by means of the slip-link, the combined 

 length of the two chains is sufficient to allow the wheel to roll off the shoe, 

 which shoe still remains attached to the carriage by means of the united 

 chains. When the shoe is not in use, the slip-link is fastened by the ring, 

 and the shoe hung upon a hook attached to one of the cheeks. When it is 

 desired to lock one of the wheels for the purpose before indicated, the shoe 

 is taken from the hook and dropped in such a position that one of the 

 wheels will run upon, or rather into it. As soon as the chain becomes 

 tight, the shoe is dragged along thereby, and the wheel rides upon it and 

 ceases to rotate. When it is desired to release the wheel, the ring is 

 slipped off the end of the toggle and the wheel rolls off, to run again upon 

 the ground in the ordinary manner; the shoe, being trailed along freely 

 behind by the chains, may then be taken up and hung again upon the 

 hook; and the slip-link may be again set as before, so that the parts shall 

 be ready for use, without delay, when occasion shall again require. 



The condition of the parts, when the ring is slipped off the toggle, is indi- 

 cated by dotted outlines in figure of the carriage. 



In constructing the guns, the trunnions are attached to a band which 

 is shrunk on to the body of the gun, a section of which, showing the seat 

 of steps, is indicated on the drawings of the gun, so that the body of the 

 gun may be hammered uniformly in forging. The elevating screw passes 



