US2633193A - Automatic self-feed die set - Google Patents

Description

March 31, 1953 J MP 2,633,193

AUTOMATIC SELF-FEED DIE SET Filed April 29, 1948 5 Sheets-Sheet 1 Ill-51.1.

- INVENTOR. JOHN 0. THOMPSON 4 rim/vi) March 31, 1953 J. D. THOMPSON 2,633,193

AUTOMATIC SELF-FEED DIE SET Filed April 29, 1948 3 Sheets-Sheet 3 IN VEN TOR.

Joy/v o. THOMPSON 1m Patentetl Mar. 31, 1953 2,633,193 AUTOMATIC SELF-FEED DIE SET John D. Thompson, Detroit, Mich., assignor of one-third to John D. Thompson, one-third to John Abplanalp, and one-third to D. Ferguson,

all of Detroit, Mich.

Application April 29, 1948, Serial No. 23,953

2 Claims.

This invention relates to a stock feeding mechanism for use in connection with reciprocating press dies and more particularly to an automatic self-feed die set.

Numerous stock feeding devices have been employed in reciprocating presses which are mounted directly on the press and receive their actuation from attachment to rotating or reciprocating parts of the press. The present invention is primarily directed tothe incorporation of a stock feeding mechanism as an integral part of a die set, such mechanism having no direct connection with any part of the press per se. The die set may be one which integrally incorporates the die members proper or the set may incorporate provision for replacement or interchange of like or different die members. One of the principal objects achieved by the incorporation of a feed mechanism as an integral part of a die set over the conventional arrangement lies in the reduction of set-up time in converting a press from one operation to another. Where the feed mechanism is mounted on the press it must be aligned and adjusted for each new die set which may be installed in the press, while the present arrangement permits a changeover from one set-up to another by the simple change of die sets. Further advantages lie in the proximity of the feed mechanism to the die members proper and the greater accuracy of feed made possible by the integral construction. In addition. a much simpler and more compact mechanism is made possible.

In a punch or forming operation it is necessary that no feed take place during the initial portion of the retraction stroke or during the final portion of theclosing stroke while the die members are inter-engaged. It is another object of the present invention to incorporate in the feed mechanism simple and novel means for preventing feed during such portions of the cycle.

A further object of the invention is to provide a simple method of adjusting the length of feed stroke.

Another object is to provide a drive for the feed which is effective during the parting stroke of the dies with a lost motion connection to render the initial portion of the parting stroke ineffective to actuate the feed mechanism.

A further object is to provide an adjustment for varying the amount of such lost motion which will in turn vary the effective feed stroke.

Another object is to provide a feed mechanism mentsurfaces of the dieset and which will accordingly require no clearance provision apart from the die opening space of any press in which the die set may be installed.

These and other objects will be apparent from an examination of a particular embodiment shown in the drawings forming a part hereof wherein: v

Fig. 1 is a plan view of the lower die shoe form: ing a part of a die set incorporating an automatic feed mechanism in accordance with the present invention and taken along the line l--l of Fig. 2.

Fig. 2 is a vertical section of the die set taken along the line 2-2 of Fig. 1.

Fig. 3 is a vertical section taken along the line 3--3 of Fig. 2.

Fig. 4 is a sectional view showing the one-way clutch employed in the feed mechanism.

Fig. 5 is a side elevation taken along the line 5-5 of Fig. 1.

Fig. 6 is a fragmentary sectional view taken along the line 6- 6 of Fig. 1.

Fig. '7 is a sectional viewsimilar to Fig. 2 showing a modified construction which could be emplayed in providing a push feed.

Referring to Fig. 2 the conventional members of the die set include a lower die shoe I0 adapted for connection to the fixed bolster plate of a press, an upper die shoe ll adapted for connection to the reciprocating bolster plate of the press, and three guide posts 12 for aligning the respective shoes. The particular die set shown in the drawings is adapted to stamp washers out of strip material and the die members proper include a lower punch 13 having a central cylindrical bore l4 and retained in position by a rectangular plate [5, as well as an upper female die member I 6 secured by a. retaining plate I! to a holding member I8 which is in turn secured to the upper die shoe by suitable means not shown.

The upper die member I6 is provided with a central recess IQ for slidably accommodating a knockout piston 20. A small punch 2| is securely held in the upper die member l6 by a set screw 22 and the lower end of such punch passes through a countersunk bore in the knockout piston 20. The enlarged head 23 of the punch 2| serves to limit the travel of the knockout piston 20 within the recess I9.

When the plunger 24 contacts a, knockout bar, not shown, at the end of the retraction stroke, it operates through pin 25'to actuate the knockout piston 20. A spring loaded yieldable pad retainer 26 is secured to the lower die shoe H] by studs 28, as shown in Fig. 6.

The operation of the members thus far described, none of which form the subject matter of the present invention, is as follows:

Starting with the beginning of the closing stroke the plunger 24, pin 25 and knockout piston would be in a depressed position due to the contact of the Plunger 24 with a knockout bar not shown. The pad 21 would lie flush with the top surface of the punch l3 and as the upper die member |6 travels down, the washer stock 29 would be gripped between the lower surface of the die It and the pad 21. Continued movement shears the outer perimeter of the washer, the knockout piston 20 being forced upward into the recess I9 by its contact with the face of the punch l3. At the same time the punch 2 I is effective to punch out the center of the washer, and at the end of the closing stroke the respective parts assume the position shown in Fig. 2. Upon retraction of the upper die shoe, the spring loaded pad retainer 26 resumes its flush position with the face of the punch l3 thereby forcing the stock 29 above the cutting edge of such punch. Upon completion of the retraction stroke the washer is ejected by the action of the plunger 24, pin and piston 28, as previously described.

It will be seen that during the final portion of the closing stroke and initial portion of the retraction stroke the stock 29 is gripped between the lower face of the female die member I6 and the upper face of the pad 21 and that such stock is penetrated by the punch I3. Accordingly, no feeding action can take place until the upper die shoe has been retracted for a sufficient distance to permit the pad retainer 25 to resume its normal position and until the contact between the die member l6 and stock 29 has been broken. In the present embodiment stock feed is efiected by the pulling stroke of a feed mechanism forming an integral part of the die set which will now be described in detail.

As will be seen in Fig. 2 the stock passes between an upper idling roller 38 and a lower driving roller 3|. As shown in Fig. 3 the lower roller 3| is keyed at 32 to a drive shaft 33 which is journaled in bushings 34 seated in the lower die shoe it, while the upper roll is journaled in a pair of floating bushings 35 Which are confined within a pair of vertical slots 36 (see Figs. 1 and 2) formed in upwardly projecting extensions 31 of the lower die shoe l0. A pair of spring loaded levers 38 pivotally seated in the extensions 3? urge the bushings 35 downwardly in their slots in order to maintain desired roll pressure on the stock. An enlarged end 39 of the lower roller drive shaft 33 is formed as the driven member of a one-way clutch shown most clearly in Fig. 4, notches and spring recesses being formed in such end in order to accommodate the clutch rolls 40. Such rolls are operative to provide a drive between the ring 4| and the driven element 35 when the ring 4| is driven in a clock wise direction, as seen in Fig. 4. The ring 4| which forms the driving element of the one-way clutch is in turn driven by a spur gear 42 through a sleeve 43 which is rotatably journaled on the drive shaft 33 by a bushing 44.

. As most clearly shown in Fig. 6, the spur gear 42 is driven by engaging teeth of a rack 45 which reciprocates vertically within a sleeve 45 in the lower die shoe I6. The rack 45 is flanged at its upper end 47 for engagement with the shoulder 48 of an internally threaded cup-shaped member 49 seated in the upper die shoe H. An adjustment screw 50 is adapted to contact the upper end of the rack 45 for driving engagement upon the closing stroke, while the engagement of the shoulder 48 with the flange 41 provides the driving engagement during the retraction stroke. The position of the adjustment screw 50 determines the amount of lost motion between the two driving engagements. The lost .motion, as will now be explained, serves both to prevent feed during the initial portion of the retraction stroke as well as to provide an adjustment for the amount of feed.

All of the figures show the die set in a fully closed positionsuch as would be assumed at the end of the closing stroke. During the initial portion of the retraction stroke, until such time as the pad 21 has resumed its flush position relative to the punch l3 and the female die member H5 has left contact with the stock 29, the clearance between the flange 41 and shoulder 48 permits the rack 45 to remain stationary so that no feed during this initial period takes place.

When the shoulder 48 engages the flange 41, the rack drives the gear 42 in a counterclockwise direction, as seen in Fig. 6, causing the ring 4| to drive the shaft 32 and roll 3| thereby feeding the stock from the time of the initial engagement of the shoulder 48 and flange 41 until the end of the retraction stroke is reached. At the beginning of the closing stroke the rack 45 again remains stationary until clearance between the top of the rack 45 and the screw 50 is taken up, whereupon the rack is driven down throughout the remainder of the closing stroke driving the gear 42 in a clockwise direction, as shown in Fig. 6. A clockwise rotation of the gear 42, as seen in Fig. 6, is not effective to drive the feed rolls due to the slippage of the one-way clutch elements 3!! and 4|, and a brake pad 5| which is urged against the drive roller 3| by spring 52 assures the release of the one-way clutch during the closing stroke.

It will thus be seen that the rack 45 moves a total distance equal to the stroke of the upper die shoe less the amount of clearance established by the adjustment screw 50 and the effective length .of feed may accordingly be increased or decreased by respectively decreasing or increasing such clearance.

The arrangement shown in Figs. 1 through 6 provides a pull feed for the stock 29 as may be desirable or necessary where the stock isso thin or flexible that it might tend to buckle with a push feed. Such pull feed, of course, requires that a portion of the stock strip remain intact after the press operation.

In Fig. '7 a modification is shown with the feed mechanism arranged to provide a push feed, as would be required where the press operation entirely severed each part from the stock strip. The rack 45 in such modification is located on the outside of the gear 42 causing such gear to rotate in a counterclockwise direction pushing 1e stock toward the center of the die set during the effective portion of the retraction stroke. The one-Way clutch elements are, of course, arranged to provide drive during such retraction stroke. In all other respects the modification of Fig. '7 operates in an identical manner to the construction shown in Figs. 1 through 6.

While the feed mechanism of the present invention has been shown as adapted to a specific die effecting either a push or pull feed, it will be understood that numerous modifications in the type of die set. and in the details of construction could be empIQyedwithout departing from the scope of my invention, as set forth in the appended claims.

I claim:

1. A unitary removable die set comprising interengaging tools mounted on fixed and reciprocably movable members, stock feed rolls mounted on the fixed member of said die set, a pinion operably connected to one of said feed rolls, a one-way friction clutch'interposed between said pinion and feed roll, a rack engaging said pinion having a lost motion connection to the movable member of said die set, said one-way clutch being drivingly actuated by movement of said rack after the initial separating movement between said die set members providing disengagement of said interengaging tools has taken up such lost motion, and means for infinitely adjusting the amount of said lost motion within a predetermined range to provide exact adjustment for the amount of stock feed produced by each separating stroke of said movable member.

2. A unitary removable die set comprising fixed and reciprocably movable members for mounting interengaging tools, stock feed rolls mounted on the fixed member of said die set, a pinion operably connected to one of said feed rolls, a one-way friction clutch interposed between said pinion and feed roll, a rack engaging said pinion having a lost motion connection to REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 113,863 Eggleston Apr. 18, 1871 169,408 Brown Nov. 2, 1875 859,220 Healy July 9, 1907 1,052,680 Marsh Feb. 11, 1913 1,907,760 Egger May 9, 1933 2,363,540 McVey Nov. 28, 1944 FOREIGN PATENTS Number Country Date 2,568 Great Britain July 10, 1913

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