GB308896A - Improvements in or relating to lathes and analogous machine tools - Google Patents

Abstract

308,896. Miley, P., and Hetherington & Sons, Ltd., J. March 30, 1928, Lathes ; drivers and carriers.-Means for driving an article such as a railway wheel for machining operations in a machine such as a lathe, comprise a U-shaped body 5 slidably mounted by means of guide strips 7 on a face-plate 4 and provided with three gripping members 11, 13, one of which is movable, for engaging the interior of the wheel &c. The members 11 are formed on or fixed to the outer limbs of the body 5 and may be adjustable thereon and the member 13 is formed as an eccentric cam attached to a pin 12 pivoted in the body. All the gripping members are serrated or otherwise formed for driving the work and all are spaced 120‹ apart. The body is normally pressed against a fixed adjustable stop 24 on the face-plate by a spring plunger 18 working in a boss 17 formed on the base 16 of the body and adjustably attached at 20 to the face-plate. A lever 15, attached to the pivot 12, provides for rotating the cam 13 by hand and may be retained in the gripping position by a trigger 31 adjustably pivoted at 33 to the face-plate and caused by a spring 34 to keep a notch 30 in engagement with the lever. In operation the body 5 is placed in such a position that a wheel may be rolled into alignment therewith, the central stub-axle of the wheel passing between the horns 9, 10 of the body and entering the central hole 26 of the face-plate. The cam 13 is then rotated by the hand lever 15 causing the cam to engage the wheel and thereupon the body to be moved radially until the grip is distributed evenly between the three gripping members. The parts are arranged so that the pressure of cutting tends to increase the grip. After the cutting operation has been completed a sliding dog 35 is placed in the path of the trigger 31 which is thereby oscillated to cause the lever 15 to be rotated in the same direction of rotation as the work and so release the cam 13. In its inoperative position the cam 13 rests against a stop 14, and motion of the cam when not in use is prevented by means of a spring plunger 42, Fig. 3, attached to the pivot 12 engaging a detent 39 on a strip 37 bolted in a recess in the body 5. The dog 35 may be slid by means of a handoperated lever and when work-holders are mounted on both sides of the face-plate the two dogs may be operated by a common sliding bar and lever. According to the first Provisional Specification, the gripping members 11 may be detachable and replaceable and the lever 15 may be operated by fluid pressure, and according to the second Provisional Specification, the trigger 35 may slide radially on the face-plate and means may be provided for stopping the rotation of the face-plate simultaneously with the release of the work, these means comprising a shaft on which the dog 35 is mounted and the action being such that after releasing the cam 13, the additional pressure on the dog rotates the shaft against the resistance of a brake or weight &c. and so actuates the means for stopping the drive. In this construction the dog may be telescopic to slide perpendicularly to the shaft or it may be pivoted on the shaft and engage a stop on the latter when in its operative position.