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Description: |
| Abstract:
In order that the objects and advantages of the present invention may be the better understood, I shall state some of the difficulties met with in existing machinery of this class, and then explain the manner in which the same are avoided. Ordinarily, the shaft to be turned is mounted upon the centers of the head and tail stocks, and the end nearest the headstock is connected and caused to rotate with the faceplate thereof by a lathe-dog. Under such arrangement the tailstock center, being stationary, is ground and worn away by the rotation of the shaft thereon, and the shaft being driven from one end only is apt to spring or twist, unless very heavy, thus greatly interfering with the speed and accuracy of the work. Heretofore it has been necessary also to dismount the shaft when the cutting-tools neared the dog, reverse the shaft end for end, carry the tools back, and finish the portion previously held by the dog. To obviate these o difficulties, I provide a faceplate for the tail stock, as well as for the head stock, and employ a dog at each end of the shaft, and provide means for driving both faceplates alike, so that the shaft is turned with equal power at both ends, and that when the tools approach the dog at either end said dog can be removed and the tools ran clear to the end of the shaft, while the latter is driven from the opposite end. To further provide for this full travel of the tools, I employ a separable dog having two tails of more than ordinary length, the extra length being necessitated by a similar extension of the lathe-centers to give room for the tools between the faceplates and the ends of the shafts. Under this plan it is not necessary to reverse the shaft end for end to finish it, and it is therefore unnecessary to run the tool stock or carriage back for that purpose. Under existing plans, however, the tool stock or carriage must be run back: with each new shaft, because the tools can work only one way. To avoid this necessity. I so construct and arrange the tool stock that it may be swung horizontally about a central pivot on the carriage, and the tools thus made to work back to the starting-point, the lathe being of course reversed with each reversal of the tool stock.
Claim:
The combination, in a lathe, of a frame, a headstock provided with a face-plate, a tailstock provided with a face-plate, a shaft carrying a pinion in mesh with the faceplate of the head-stock, a sleeve mounted upon the shaft and carrying a pinion in mesh with the faceplate of the tail-stock, said sleeve adapted to slide upon the shaft, but to rotate only in unison therewith, and an arm projecting from the tailstock and having the sleeve loosely journaled in it, whereby the sleeve and its pinion are maintained always in fixed relation to the faceplate of the tailstock. In a lathe, the combination of a frame, A, a head-stock, B, provided with a face-plate, D, a tail-stock, X, provided with a face-plate, I', a shaft, F, provided with a pinion, E, meshing with faceplate D, a sleeve, G', encircling and adapted to slide upon the shaft F, a pinion, 112, carried by said sleeve and meshing with faceplate I', and an arm, J', swiveled upon the spindle Y of the tail-stock, and having the sleeve G' journaled in it. |
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