US790847A - Step-feed mechanism for machine-tools. - Google Patents

Description

PATENTED MAY 23, 1905.

J. MILLS. STEP FEED MECHANISM FOR MACHINE TOOLS.

APPLICATION FILED DEC. 27. 1904.

511mm" for UNITED STATES Patented May 23, 1905.

PATENT OEEIcE.

JAMES MILLS, OF CINCINNATI, OHIO, ASSIGNOR OF ONE-HALF TO ALBERT S. SMITH, OF CINCINNATI, OHIO.

STEP-FEED MECHANISM FOR MACHINE-TOOLS.

SPECIFICATION forming part of Letters Patent No. 790,847, dated May 23, 1905. Application filed December 27, 1904. Serial No. 238,333.

tween the reversible driving-shaft and a stepfeed mechanism, with a trip and stops adapted to automatically cut out such positive connection at intervals in the reverse rotations of the driving-shaft, there being auxiliary light friction connection between the driving-shaft and step-feed mechanism adapted to release the trip at the beginning of the reversal of the driving-shaft and to retain the trip in engagement with the stop until the reversal of the driving-shaft.

While this invention is applicable to various forms of step-feed, its principal utility is in connection with a shaper of the geared type, and it is accordingly so illustrated.

The chief object of this invention is to adapt a positive step-feed mechanism to the conventional feed mechanism of a shaper with as little as possible of change, addition, or reorganization of parts.

The features of the invention are more fully set forth in the description of the accompanying drawings, forming a part of this specification, in which Figure 1 is a side elevation of a shaper. Fig. 2 is a section, enlarged, on linear m, Fig. 1. Fig. 3 is an enlarged sectional view of the releasing mechanism of the power feed for the table. Fig. 4 is an enlarged section on line w w, Fig. 2, illustrating the stops for releasing the power in elevation.

1 represents the frame of the shaper.

2 represents the ram traversing gibbed ways upon the upper portion of the shaper. Said ram is provided with a rack, to which motion is imparted by the usual gearing, well known in shapers of this class, but not shown in the drawings.

3 is the table to which the step-feed is to be imparted. It reciprocates horizontally in ways on cross-head 3, which in turn may be reciprocated on vertical ways l on the front portion of the frame 1.

5 represents a reversible driving-shaft, suitably journaled in hearings in the frame 1 and projecting outwardly therefrom. 6 represents a gear fixed to said shaft and in mesh with a gear upon shaft 7, said shaft 7 being provided with pulleys for transmitting a forward and reverse rotation to the gear 6. (See Figs. 1 and 2.) This is accomplished through the usual belt-reversing pulleys on driving-shaft 7. This reversing mechanism is not shown, as any well-known form may be employed.

8 represents a gear integral with or fixed to gear 6, adapted to mesh with a gear on shaft 9, which gear in turn is in mesh with a rack of the ram 2.

10 represents a sleeve loose upon shaft 5, provided with a flange 11 at one end thereof.

12 represents a plate fixed to the flange 11 of sleeve 10 by means of bolts. This plate 12 is provided with a gibway 13, the center portion of which is bored out and within which bore a feed-screw 14 is provided.

15 represents a slide-plate gibbed to plate 12 and provided with a nut 16, having threaded engagement with screw 14 for adjusting the slide-plate upon the plate 12.

17 represents a connecting-rod pivotally connected to slide-plate 15 for transmitting motion to the pawl-plate 18, journaled upon the cross-feed screw of the cross-head 3.

19 represents a ratchet-wheel fixed to the cross-feed screw 20.

21 represents a pawl upon the pawl-plate 18, adapted to be engaged with the ratchetwheel 19.

22 represents a sleeve fixed to the shaft 5 and provided with a flange 23 and lying between the flange 11 of the sleeve 10 and the plate 12.

24 25 represent leather packing adapted to frictionally engage with the flange 11 and plate 12 for driving the same.

So much of the mechanism above described is common to the prior art. In the operation of such prior step-feed devices the connection between the reversible driving-shaft and the step-feed mechanism is the friction elements described and shown between driving-shaft 5 and sleeve 10. Ashort step-feed is required, and hence it is necessary that sleeve 10 shall only receive a part of the opposite rotations of shaft 5, so that with such prior devices positive stops are provided for the sleeve 10, which limits its rotation in opposite directions relative to the opposite rotations of shaft 5. It is evident that the friction must be powerful enough to give the step-feed and that it must be weak enough to allow of constant slippage during the intervals at which the sleeve 10 is held at rest when engaged with the opposite stops. In addition to the disadvantages of a friction power feed the slippage is a wearing element which constantly depreciates the strength of the feed. It requires constant adjustment and renewal and at that is a makeshift at best. With my invention I dispense with the element of a strong friction connection for the step-feed and substitute a positive connection or clutch between the driving-shaft 5 and the sleeve 10, which trips to throw out this positive clutch during the intervals at which the sleeve 10 is to remain stationary; but I retain an auxiliary light friction between the reversible driving-shaft 5 and the sleeve 10 sufficient to unshift the trip at the moment the drivingshaft is reversed and sufficient to hold the trip in position of engagement with the opposite stops during the said interval at which the sleeve 10 is stationary. I will now describe the features of novelty by which 1 preferably accomplish the said result.

From shaft 10 is projected a radial arm 26, the outer end of which is turned parallel with the shaft 5 and which turned end overhangs a gear-wheel 27, keyed to shaft 5, as shown in Fig. 2. The bent end of said arm 26 is provided with a tripping clutch-pin 28, the inner end of which is adapted to engage into the teeth of gear-wheel 27, so as to form a positive connection or clutch between shaft 5 and sleeve 10. Thus it will be seen that the table 3 is given its step cross-feed by a positive power transmission.

29 represents a coil-spring seating within the bore of the arm 26 for imparting normal outward tension to the detent-pin 28.

30 represents a cam-plate fixed to the detent-pin 28, adapted to engage the stops 31 32, adjustably mounted in lugs 33 34:, said lugs being formed integral with the plate 33, said plate being secured to the frame 1. Thus as the cam-plate 30 engages either one of the stops it will throw the tripping clutch-pin 28 out of engagement with the gear 27, and thereby arrest the motion of sleeve 10 and cross-feed mechanism heretofore described in connection therewith.

Looking at Fig. 4, assume that gear-wheel 27 is moving in a direction to carry pin 28 toward the stop 31, the cam on plate 30 just engaging the edge of the stop 31. The continued movement of pin 28 in that direction lifts clutch-pin 28 from engagement with gearwheel 27. The sleeve 10 is stopped. Hence the step -feed is cut out, while the shaft 5 and gear 27 continue their rotation in said direction, the light friction permitting of the necessary slippage between shaft 5 and sleeve 10. This light friction is sufficient to hold the pin 28 at this extreme position of movement until the shaft 5 is reversed, when the friction will shift sleeve 10 with shaft 5 in the oppo site direction of rotation, disengaging the plate 30 from the stop 31, so that the clutch-pin 28 again engages into the teeth of gear-wheel 27 and the step-feed mechanism is positively actuated during the reverse drive of shaft 5 until the plate 30 engages the opposite stop 32.

This mechanism is simple, readily attachable to conventional shapers of this class, and it effectually eradicates the friction power step-feed, with its attendant disadvantages. Thus it will be seen that I have provided a positive table step-feed for a shaper and adapted it to the established shaper organization in.

a very simple and effective manner.

Having described my invention, I claim In a shaper-table-feed mechanism, a reversible driving-shaft, a toothed wheel fixed to an intermediate portion thereof, a sleeve on the projecting end of said shaft, friction connections between the outer ends of said shaft and sleeve, a crank-disk on the outer end of the sleeve, connections between the said crank-disk and the table-feed mechanism, a pawl on the inner end of said sleeve adapted to normally engage with said toothed wheel, and tripping-stops supported by the frame adapted to disengage said pawl at predetermined intervals in the reverse rotation of the sleeve, substantially as described.

In testimony whereof I have hereunto set my hand.

JAMES MILLS.

WVitnesses:

OLIVER B. KAISER, LUISE BECK.

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