The means employed to effect these objects are as follows:—
In [Fig. 582] f represents the independent feed spindle and s the lead-screw: f is splined to drive a, a′ and a′′, which is a sleeve in one piece, and consists of a circular rack at a, a bevel pinion at a′, and a second bevel pinion at a′′. This sleeve may be operated in either direction along f by rotating the pinion b. As shown in the cut a′ and a′′ are both out of gear with the bevel-wheel c, but if b be rotated to the right then a′ will be in gear with c, or if it be operated to the left then a′′ will be in gear with c. Now the direction of rotation of c will be governed by which pinion, a′ or a′′, drives it, and these are the means by which the direction of the feed traverse and also of the cross feed is determined.
If none of the feeds are required to operate, the sleeve occupies the position shown in the cut, and the circular rack at a simply rotates while b and all other parts remain at rest. On the same central pin as c is the pinion d driving a spur gear e′′. On the same centre pin as e is the gear f driving g, which is on the same central pin as c and d. The gear h is fixed to and rotates with g and drives i; all these gears serving to reduce the speed of motion when operating to feed the carriage traverse in either direction.
A gear j is carried on the end of a lever k, being pivoted at l. In the position shown j is out of gear with all gears, but it may be swung to the right so as to engage with wheel i and wheel m, and convey the motion of i to m. Upon the same spindle as m is the pinion n, engaging with the rack o, which is fast on the lathe bed. This completes the automatic feed traverse.
For a hand feed traverse, pinion p is employed to drive m, which is fast to n. The cross feed is self-acted by moving lever k to the left, causing it to engage with pinion q as well as with t, q being fast on the cross feed screw. To lock j in either of its three positions there is provided on lever k a spring locking pin r, shown clearly in [Fig. 584], which represents an irregular section of the gearing viewed from the headstock of the lathe. The pin r is pressed inward by the spiral spring shown, and has a conical end fitting into holes provided in the apron to receive it. There are three of these holes, shown in dotted lines at a b c in [Fig. 582]. When the pin is in a the lever k, and therefore wheel j, [Fig. 582], is locked out of gear; when it is in hole b wheel j is locked in gear with i and m, and when it is in c the wheel j is in gear with t and q, and the cross feed is actuated.
A similar locking device is provided for the pinion b for actuating a; thus in [Fig. 582] b is the lever, the spring pin being at r′′; or referring to [Fig. 584], x is the lever fast at x on the pin driving b, and r′ is the spring pin.
The nut for the lead screw is secured either in or out of gear with the screw in the same manner, x′, [Fig. 583], being the lever and r′′ the spring pin.
Fig. 585.