US2216872A - Stock feeding means for automatic machine tools - Google Patents

Description

Oct. 8, 1940. s. BAXENDALE 2,216,572

STOCK FEEDING MEANS FOR AUTOMATiC MACHINE TOOLS Filed Sept. 12, 1938 FIGJ.

INVENTOR SAMUEL BAXENDALE ATTORNEYS Patented Oct. 8, 1940 PATENT OFFICE STOCK FEEDING MEANS FOR AUTOMATIC I l i TOOLS Samuel Baxendale, Dearborn, Mich. Application September 12, 1938, Serial No. 229,573

Claims.

The invention relates to stock feeding means for automatic machine tools and more particularly to that type in whichthe stock is gripped during the feeding movement by a surrounding collar which is'tilted for clamping engagement.

Figure 1 is a longitudinal section showing my improved feeder as arranged within the hollow spindle of the machine tool;" 1

Figure 2 is a similar view or amodified construction;

Figure 3 is an end elevation of Figure 2;

Figure 4 is a longitudinal section at right angles to Figure 2;

Figure 5 is a view similar to Figure another modification;

Figure 6 is an end elevation thereof;

Figure 7 is a section illustrating a modified construction of the gripping collar.

The principle underlying stock feeding devices of the above mentioned type is that a collar which surrounds and loosely fits the stock bar when in a plane perpendicular to the longitudinal axis of the bar will, if tilted at an angle, form a gripping engagement. It is, therefore, essential in the construction of a feeder that the collar should be automatically tilted when moved in the feeding direction and released to assume a plane perpendicular to the axis during movement in the opposite direction. One method for tilting the collar which has heretofore been used is to provide an inclined abutment adjacent thereto which during the initialforward movement of the feeder, bears only on one side of the axis of the collar. This is generally effective, but its action is not positive for it is dependent upon the inertia of the collar and at times it will merely slide the collar over the stock bar without gripping the same. Another 1 showing ,method is to form the collar of unequal cross section on opposite sides thereof so that centrifugal force may tend to turn it at an inclination to the axis. This also is non-positive depending upon the angular velocity and other variable factors. Stillanother method is to press the collar against the inclined abutment by a coil springwithin the feeder and surrounding the stock bar. With this there is nothing to insure that the pressure of the.

spring will tilt the collar, it depends upon the point of contact between the spring and the collar in relation to the point of contact between the collar and the abutment. It sometimes has the opposite from the desired effect, tending to move the collar into a plane perpendicular to the axis.

It is the primary object of the present invention to obtain a construction in which the collar is subjected to a tilting force sufficient to insure a 5 gripping action whenever the feeder is moved forward. This'I have accomplished by subjecting the collar to resilient pressure definitely located to be at all times spaced from the point of bearing of the "actuating member thereon. Various specific constructions will accomplish this purpose. Thusas shown in Figure 1, A is the hollow spindle through which the stock is to be fed. B is an actuating tubular member within this spindle having an internal shoulder C for bearing against a tubular bushing D having an inclined forward end E. F is the feed collar located adjacent to the inclined face E. G is a pin projecting forward from the member D and engaging an aperture in the collar F to form a rotative coupling therewith. H is a pin or lug projecting forward from the collar F at a point preferably diametrically opposite the pin G, and I is a coil spring engaging this pin or lug and bearing with its opposite end against a cap J which is threadedly engaged with the member B. The member D is also preferably held from rotation within the member B by suitable means, such as the screw K. With the construction just described the pressure of the spring I is always located diametrically on the opposite side of the collar from the bearing of the actuating member, so that there will be a positive gripping of the stock bar whenever the feeder moves forward.

With the modified construction shown in Figures 2 to 4 the member D ismilled to form the forward inclined face E between forwardly projecting furcations L. The collar F is also fiattened on its opposite side to fit between these furcations which serve to prevent any relative rotary movement. At the forward end of the furcations there are formed shoulders M for the seating of an annular'member N which may be secured to its seat by peening over the end of the furcations, as indicated at O. A lug or pin N on the member N is located opposite the low side of the inclined face E and serves to hold a coil spring I, which bears against the collar F. This: construction will, therefore, function the same as that previously described. 50

In Figures 5 and. 6 another modification is shown comprising a pusher member P which has an inclined forward face P. Q is. a resilient member, preferably a sheet metal stamping, which is attached at Q to one side of the member P projecting forward therefrom and then return-bent to bear against the collar F This collar is not therefore rotatively coupled to the member P, but the point of bearing thereon of the resilient member Q is located to be diametrically opposite from the advance end of the inclined face P. This will insure the positive gripping action.

The gripping collar is usually formed with parallel frontand rear faces and with its central bore perpendicular to these faces, Where it is desired to use the feeder on finished bars of stock the corner between the face of the bore and the radial faces may be rounded so as to avoid any marking. Where, however, the feeder is used upon unfinished stock the firmness of the grip may be increased by having a sharp edge. A

still better gripping construction may be formed as shown in Figure 7, where the radial faces F of the collar are inclined to the axis or slightly coned. Also, the bore through the collar may be slightly undercut as indicated at B so as to form acute-angled edge portions S for biting into the stock bar. I

What I claim as my invention is:

1. A stockfeeding device comprising a tubular actuating member having a forward face inclined to the longitudinal axis, a symmetrical collar arranged adjacent to said inclined face, and means for resiliently pressing said collar toward said inclined face located to bear only at a point laterally spaced from the advanced portion thereof.

2. A stock feeding device comprising a tubular actuating member having a forward face inclined to the longitudinal axis, a symmetrical collar arranged adjacent to said inclined face,

and means for resiliently pressing said collar against said inclined face located to bear only at a point substantially diametrically opposite the advanced portion of said face.

3. A stock feeding device comprising a rotary tubular actuating member having a forward face inclined to the longitudinal axis, a symmetrical collar adjacent to said inclined face, means for preventing relative rotation. of said collar and actuating member, and resilient means for pressing against said collar locatedwith respect to the same to bear only at a point substantially diametrically opposite from the advanced portion of said inclined face.

4. A stock feeding device comprising a rotary tubular member having a portion of its forward face in advance of other portions thereof, a symmetrical collar adjacent to said forward face, and resilient means located with respect to said pusher to press rearwardly against said collar only at a point opposite said advanced portion of said forward face.

5. In a device of v the class described, a stock feeding tube, means for slidably supporting bar stock axially within the tube, and stock gripping means in the tube to positively feed the stock with the tube in one direction only, said gripping means including a ring loosely encircling the stock, an abutment in the tube engageable with a relatively small section of the ring to tilt the same on the stock,- and a spring engageable with an opposite face of the ring and exerting a force of compression on said ring to maintain in tilted stock gripping position when the tube is moved in said one direction.

SAMUEL BAXENDALE.

Images