US3448604A - Blank feeding device for presses - Google Patents

Description

K. FINSTERWALDER 3,448,604

BLANK FEEDING DEVICE FOR PRESSES June 10, 1969 Shgt Filed July 21. 1966 flm V 4/ //W// (q iii! INVENTOR Mun-r Flmrelewnmea ATTORNEYS June 10, 1969 Filed July 21. 1966 K. FINSTERWALDEF ATTORNEYS K.- FINSTERWALDER June 10, 1969 BLANK FEEDING DEVICE FOR PRESSES m 4.: x E Q m 3 Hw A Q .fiwk Q 4 RQ a a Q, 1Q. 4 NH m m uuAou 6 dunn lll m 4% M. W m

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ATTORNEYS United States Patent BLANK FEEDING DEVICE FOR PRESSES Kurt Finsterwalder, Goeppingen, Germany, assignor to L. Schuler G.m.b.H., Goeppingen, Germany Filed July 21, 1966, Ser. No. 566,792 Claims priority, application Germany, July 30, 1965, Sch 37,467 Int. Cl. B21d 45/00, 43/06 US. Cl. 72346 7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a blank feeding device for presses, in particular coin presses, having a slider member which supplies the blank, a tong-like device which holds the blank in front of the pressing tool and a device for removing the pressed workpiece.

In a horizontal impact extrusion press for backward impact extrusion it is known to feed the blanks by means of a lever into their position in front of the die axis and to hold them there by means of holding tongs. After the pressing process the finished tube is stripped off the plunger and conveyed away. In these presses, the stripping device or a further additional device provides also the conveyance of the finished workpiece away from the axis of the machine tool. These devices are somewhat costly in their construction.

In another known feeding device for a thread rolling machine a common slider member is provided for feeding the workpiece to be treated into a position in line with the tool axis and for removing the finished workpiece from the tool axis, the slider member having a recess in which the workpiece to be treated in conveyed into the tool axis and the leading edge of the slider member ejecting simultaneously the finished workpiece from the tool axis. In this arrangement, however, the workpiece conveyed into position in line with the tool axis is removed from the recess of the slider member and pressed towards the tool by means of a particular feeder rod which is displaceable in line with the tool axis. After the treatment the workpiece is then moved by an ejection device back into the conveyance plane so that it can be engaged by the edge of the slider member and conveyed further. In this device the workpiece is thus not held in the ready position in line with the tool axis prior to its treatment.

The invention consists in that the supply plane in which the blank is supplied to and held in the ready position in line with the press axis lies outside the plane in which the workpieces are removed from the press axis and which extends parallel to the supply plane.

The particular advantage of the invention resides in the fact that a special holding device which holds the blank in the ready position in line with the press axis until the plunger introduces the blank into the tool can be disposed in the conveyance plane in which the blank is supplied. During the subsequent removal of the workpiece from the tool and the press axis, however, the holding device which lies in the supply plane does not interfere with the ejection process, because the ejection occurs in another plane which extends also perpendicularly to the press axis. The distance between the two planes depends upon the dimensions of the parts of the holding device which are located in the region of the press axis and the tool. This distance is selected so that the finished Workpiece can be moved during ejection past the holding device, that is to say the ejection process has been arranged to take place in a plane in which the holding device does not interfere with the ejection.

In one embodiment according to the invention the minimum spacing by which the ejection plane is offset relatively to the supply plane may correspond to the thickness of the thickest blank likely to be used. This assumes that the parts of the holding device holding the blank in the ready position are also not thicker than the blanks.

In an embodiment of the invention a slider member is disposed in the supply plane and another slider member is disposed in the ejection plane, the sliders being displaceable in difierent radial directions towards the tool axis. The slider member in the supply plane moves the blank into a position in front of the tool where it is held by the holding device until it is introduced into the tool by the plunger. After it has been conveyed into the ejection plane the pressed workpiece is removed by the ejection slider disposed in the ejection plane away from the region of the tool and the plunger. This embodiment of the invention is particularly suitable when the feed direction of the blank and the direction of the ejection movement of the finished workpiece must be freely selectable.

In another embodiment of the invention in which the ejection direction coincides with the supply direction a common slider member is provided for both planes, the slider member being provided with steps. By means of the leading edge of one step the slider member moves the blank into the ready position in which it is held by the holding device, and by means of the leading edge of another step the forward moving slider member pushes the finished workpiece out of the region of the tool. This embodiment of the invention has the great advantage that only one slider member must be provided and the whole supply device and ejection device becomes very simple thereby.

Between the step of the slider member for supplying the blanks and the step for ejecting the workpiece a further small step may be provided so that the surface which rests against the surface of the blank and the surface which is turned towards the lower plunger or die when the finished workpiece is ejected are slightly offset relatively to each other. This has the advantage that on the one hand the blank has not too much play during the feed; on the other hand, however, the surface which is turned towards the lower plunger or die during the ejection of the workpiece has a small distance from the end face of the lower plunger, because for ejecting the workpiece the lower plunger must travel forwardly at least through a distance such that its end face is disposed in the same plane as the foremost parts of the holding tongs.

When blanks are treated the thickness of which is less than the thickness of the holding tongs or grippers, a slider member can be used in which the recess in which the blank to be supplied is located is slightly shallower because the walls of the recess are to embrace the blank to be supplied as closely as possible. In this case the above mentioned step is slightly bigger.

Known holding devices are constructed like a pair of tongs wherein at least one arm of the tongs is displaceable against the effect of a spring tending to close the tongs. A further embodiment of the invention relates to a horizontal press with such a holding device and consists in that the movable arm of the holding device has an edge serving as an ejection device. When the tongs of the holding device are closed in order to hold a new blank in the ready position, one edge of the movable arm or jaw abuts against the workpiece located in the ejection plane and conveys it out of the tool region. This embodiment of the invention is particularly advantageous when the ejection direction coincides with the direction in which the movable jaw of the holding device moves during clos- After pressing the workpiece is displaced by means of a movable part of the lower tool or die into the ejection plane from where it is conveyed away by the ejection device. In a prefered embodiment of the invention, that is to say, in a horizontal coin press, the treated workpiece is moved by the die into the ejection plane in front of the tool.

During ejection, the forward end face of the die is, therefore, located in or slightly in front of the plane containing the front surface of the holding tongs. After the ejection the die moves back until its forward end face is disposed in the plane of the front surface of the press ring. With the die at standstill in this position the new blank is inserted by the slider member. This has the advantage that the blank slides along the forward end face of the die during insertion and cannot tilt. In other embodiments the die can be returned in one continuous movement into its hindmost position without a pause.

In embodiments of the invention the operative edge of the ejection device may be so dimensioned, such as by varying thickness, that it can engage the workpiece not only when the latter is located in the ejection plane, but also when the workpiece is accidentally not moved into the ejection plane by the lower tool or die, but remains adhering to the upper tool or punch, and is moved back into the dead point position of its stroke movement which corresponds to the rest position. This embodiment of the invention has, therefore, the advantage of an additional protective device and increased security against operational disturbances.

The varying thickness of the edge may be constituted by a plurality of offset steps arranged so that the width of the slider member increases from the front to the back. Since the punch attached to the ram travels back whilst the slider member ejects the workpiece the gap between the lower plunger or die standing still in its foremost position and the receding upper plunger or punch increases continuously during the insertion movement of the slider member. The varying thickness of the slider members takes this into account. The slider member can be constructed so that in each phase of the movement nearly the Whole gap between the die and the punch is taken up by a corresponding section of the slider member.

Further features of the invention are clear from the following description of an embodiment of the invention in conjunction with the claims and the drawing. In an embodiment of the invention the individual features may be realised each by itself or a plurality thereof in combination.

One embodiment of the invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 is a plan view of the essential parts of an embodiment in form of a horizontal coin press,

FIG. 2 is a section along the line II-II of FIG. 1,

FIG. 3 is a section through the press tool on an enlarged scale, the supply device being omitted,

FIG. 4 is a view of the supply device for blanks,

FIG. 5 is a section along the line V-V of FIG. 4,

FIG. 6 shows the parts illustrated in FIG. 5 in a different movement phase, and

FIG. 7 is a section along the line VI-VI of FIG. 4, but in a different embodiment of the invention.

In the embodiment of the invention illustrated in the drawings a main press shaft 1 is driven by a motor 2 by way of a belt drive 3 and a clutch 4. An eccentric member 5 which drives toggle members 7 and 8 by way of a guide member 6 is attached to the main press shaft 1. One end of the toggle member 7 is pivotally mounted in a bearing shell 10 attached to the press housing 9, its other end is pivotally connected to the toggle member 8 at a toggle joint 11 which is also engaged by the guide member 6. The other end of the toggle member 8 is mounted in a bearing on a ram 12 which is displaceably guided in the housing. The main press shaft 1 carries a sprocket wheel 13 which is connected by means of a drive chain 14 to a sprocket wheel 15 which has the same number of sprockets and which is attached to a control shaft 16. Cam discs 17 and 18 are attached to the shaft 16 and the peripheries thereof co-operate with rollers 19 and 20 carried by the ends of two- armed levers 21 and 22, which are pivotal about a shaft 6 8. The free arm of the lever 21 carries at its end a presser member 23 which co-operates with the rear end of a rod 24 which is longitudinally displaceable in the press housing and which carries at its forward end a conical member 25 which cooperates with the periphery of a roller 26. The roller 26 is mounted on a member 29 of holding tongs or grippers which can be rotated about a pin 27 against the efifect of a spring 28. The parts 17, 21 and 24 impart a movement to the holding tongs. The rod 24 is driven by the presser member 23 against the effect of a spring 30 which holds the rear end of the rod 24 in contact with the presser member 23.

The free arm of the two-armed lever 22 carries a presser member 34 against which rests under the effect of a spring 32 the rear end of an ejector rod 31 which is axially displaceable in the press housing. This spring 32 presses by way of a plate 39 against the inner surface of the bottom of a cup-like tool carrier 33 which is guided axially displaceably in the press housing. Against the outer bottom surface of the cup-like tool carrier rests one end of the ejector rod 31, as best seen in FIG. 3. The stationary end of the spring 32 is supported on the rear surface of a press ring 35 which is inserted from inside into a cap nut 36 which is screwed on to a threaded tubular member 37 rigidly connected to the press housing. A rearward die 38 which in upright coin presses is called lower die or lower tool is attached by means of a cap nut 40 to a threaded tubular member 41 of the plate 39.

A punch 42 which in the case of upright coin presses is called upper die is attached by means of a cap nut 43 to the threaded tubular member 44 of a press plunger 45 which in turn is attached by means of a cap nut 46 to the ram 12.

A further cam disc 47 is attached to the shaft 16. Whereas on each of the cam discs 17 and 18 the periphery forms a cam and the rollers 19 and 20 therefore rest against the periphery of these cam discs, in the case of the cam disc 47 the edge of the side surface forms a cam with which a cam roller 48 co-operates. The cam roller 48 is rotatably mounted at the end of a lever 49 which is attached to the end of a rod 50. The rod 50 is rotatably mounted in the press housing. The other end of the rod 50 carries a lever 51, the free end of which is pivotally connected to a link 52 which in turn is pivotally connected to a slider member 54 which is displaceably guided on a base plate 53.

The rearward surface 55 of the slider member 54 lies in the plane of the front surface 56 of the press ring 35. The slider member 54 has a portion in which the rearward face is set back forming a step 60 therein, so that the portion 57 of the rearward surface lies at a distance from the plane 56 which is slightly greater than the thickness of the blank 58 to be treated. The front surface 56 of the press ring 35, the step or shoulder 60 and the rearward surface 57 form a pocket which is closed at the bottom by the upper flanged edge 59 of a plate 61. This plate is attached to the base plate in such manner that its position can be adjusted. Blanks 58 are inserted into the pocket through a supply duct 62. During the feed movement of the slider member 54 a blank 58 supplied by the duct 62 is pushed by means of the step 60 along the plane 73 into a position in which it is held in front of the tool centre by means of holding tongs or grippers which are formed by a shaped member 63 on the one hand, this member being attached interchangeably and adjustably on the displaceable gripper member 29, and on the other hand by the bent over edge 59 of the plate 61. Under the effect of the spring 28, the shaped member 63 urges a blank 58 located in the ready position against the edge 59 and thus holds the blank in the ready position. When the punch 42 attached to the ram engages the blank and pushes it into the opening of the press ring 35 the displaceable member 29 of the holding tongs is pivoted upwardly by the driving parts 17, 21, 24, 25, 26 about the bearing pin 27 against the effect of the spring 28, so that even when there is no blank 58 in front of the tool the advancing punch 42 does not run against the edge of the shaped member 63 whereby the punch 42 and the shaped member 63 could be damaged.

During the pressing process the forward end face 64 of the rearward die 38 is disposed within the central recess of the press ring 35 as shown in FIG. 5. The advancing punch 42 attached to the ram engages the blank 58' located in the ready position and presses it into the recess of the press ring 35 and against the forward end face of the rearward die 38 which is supported by means of the parts 41, 39 on the bottom of the tool holder 35 which in turn is supported during pressing by the stationary surface 65 which absorbs the operating pressure. After the pressing process has finished the punch 42 moves out of the opening of the press ring 35, the rearward die 38 and the finished workpiece or coin still standing still initially in the press ring. When the punch 42 attached to the ram has travelled through a certain path length the rearward die 38 with the coin follows. This has the advantage that the coin does not normally adhere to the punch 42 and therefore the ejection of the finished coil can occur always in a definite plane. The rearward die 38 moves then out of the pressring 35 and pushes the finished coin 58' forward into the plane 66 (see FIG. 6) which lies in front of the forward surface of the shaped member 63 attached to the gripper member 29. In this position a leading edge 67 of the slider member 54 now moving inwardly strip the coin 58' off the end face 64 of the rearward die 38 and ejects it laterally. The leading edge portion of the slider member 54 has a thickness such that during this insertion movement of the slider member 54 a coin which may still adhere to the punch 42 is stripped off. Since the punch 42 is still moving back into its starting position the width of the gap between the rearward die 38 which stands still in the plane 66 and the punch 42 which still moves backward increases continuously. Consequently the width of the slider member 54 increases in a lengthwise direction from the leading edge 67 constituting a plurality of steps thereby, so that always the major portion of the width of the gap is filled by the leading end portion of the slider member 54 and thus an assurance is given that even workpieces leaving in an irregular manner are ejected always in the feed direction of the slider member 54.

Thereafter the rearward die 38 moves back into the press ring 35 until its forward surface 64 lies in the plane of the forward surface of the press ring 35. During this phase of the movement the slider member 54 stands still. When the rearward die 38 has attained this position the slider member 54 moves forward in its feed direction and pushes by means of the step 60 the new blank 58 located in the pocket formed by the surfaces 56, 57 and 60 forward into the ready position in front of the recess of the press ring 35. The rearward die 38 moves then again into the position illustrated in FIG. 5 and a new pressing process can start. The forward movement of the rearward die 38 is effected by means of the driving parts 22, 31, the rearward movement is effected by the spring 32. The rearward movement of the rearward die 38 may alternatively occur in a single uninterrupted movement; in this case the forward end face 64 of the die 38 thus does not remain in the plane 56 of the front surface of the press ring 35 until the new blank 58 is inserted in the ready position.

The thickness of the shaped member 63 corresponds in general to the greatest thickness of the blanks likely to be treated on the machine. Accordingly, the stroke of the rearward die 38 is also adjusted so that its end face 64 is located during ejection in the plane 66 in which also the front surface of the shape member 63 is located. Accordingly, the surface portion 70 of the slider member 54 must also be disposed so that the distance of this surface from the surface 56 corresponds at least to this maximum blank thickness. Mostly this distance is slightly larger in order that during ejection the surface 70 of the slider member 54 does not slide over the end face 64 of the die 38. The distance of the surface 57 from the surface 56, however, must not be more than a few tenths of a millimetre greater than the actual thickness of the respective blanks treated in order that the blanks 58 supplied do not have too much play in the pockets and cannot tilt therein. Thus, if the treated blanks have a smaller thickness than the maximum thickness provided, an interchangeable and adjustable head member of the slider member 54 is used in which between the surface portions 70 and 57 a step 71 is provided, the magnitude of which is determined by the difference between the maximum blank thickness and the thickness of the respective blanks used.

FIG. 7 illustrates a different embodiment of the invention. In this embodiment of the invention the blank is not pushed off the rearward die 38 by the leading edge 67 and if necessary by the steps 69 of the slider member 54, but by a downwardly projecting edge 72 of the shaped member 63 of the displaceable gripper member 29. In this case it may be preferable to derive not only the opening movement of the gripper member 29 positively from the shaft 16 but also the closing movement, during which latter in the case of the present embodiment the edge 72 ejects the finished coin 65 from the die 38.

What I claim is:

1. Apparatus for feeding blanks to a horizontal press, particularly a coining press, and for removing the pressed workpiece therefrom, comprising a common slider member for effecting both the feeding and removal functions, said slider member having a stepped configuration, the leading edges of the steps thereof cooperating with a blank or a pressed workpiece, respectively, the steps being offset with respect to one another *by a distance at least equal to the maximum thickness of a blank employed, whereby the feeding of the bank and the removal of the pressed workpiece are accomplished in two spaced parallel planes, and further including a tong-like holding device for retaining the blank in a predetermined position with respect to the press tool.

2. Apparatus according to claim 1, characterized in that a further step is provided between the step for feeding the blank and the leading edge for ejecting the finished workpiece.

3. Apparatus according to claim 2, with a holding device having at least one displaceable jaw, characterized in that the removal device is constituted by an edge portion of the displaceable jaw of the holding device.

4. Apparatus according to claim 1, characterized in that the workpiece is moved into the removal plane by a part associated with the lower tool or die.

5. Apparatus according to claim 1, characterized in that the leading edge of the step serving for removal of the workpiece in the removal plane has a widened portion which is adapted to engage also a workpiece adhering to the press punch and carried by same into a plane spaced from the removal plane.

6. Apparatus according to claim 5, wherein said widened portion comprises two offset steps.

7. Apparatus according to claim 1, wherein the motion of the slider member is coordinated with the cycle of the press such that the return movement of the die from the removal plane into the press plane is interrupted so that the die remains stationary in the plane of the front surface of the press ring during the feed movement of a new blank.

3,171,143 3/1965 Storch et a1. 7899 X 3,283,551 11/1966 Kraft et a1. -3 72 421 X References Cited UNITED STATES PATENTS CHARLES W. LANHAM, Primary Examiner. Hicks 72-346 5 E. SUTTON, Assistant Examiner.

Smith 7899 X Frahm 72 346 US Cl. X.R.

Kruse et a1. 78-99 10-12;72421, 427, 424 Danly et a1. 72405

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