US3850315A

US3850315A - Reciprocating feed mechanism

Info

Publication number: US3850315A
Application number: US00380868A
Authority: US
Inventors: J Plaister; R Baugh
Original assignee: Taylor and Challen Ltd
Current assignee: Taylor and Challen Ltd
Priority date: 1972-07-21
Filing date: 1973-07-19
Publication date: 1974-11-26
Anticipated expiration: 1991-11-26
Also published as: GB1421333A

Abstract

This invention relates to a reciprocating feed mechanism of the kind which is suitable for feeding individual blanks between the dies of a coining press and which comprises a reciprocating slide carrying a pair of gripper arms adapted to grip and release the individual blanks. The slide and gripper arms are each operated through a separate linkage mechanism by a respective cam surface on cam means common to both linkage mechanisms, and a sliding connection is provided in the linkage mechanism, operating the gripper arms which is such as to allow reciprocation of the slide and gripper arms independently of actual operation of the gripper arms. Each of the blanks which is to be carried is picked-up by the gripper arms at a loading station where the blank lies on a horizontal support surface and is held in the correct position for gripping by the action of a vacuum pump which evacuates air from an aperture in the support surface directly beneath the blank.

Description

atet [191 United States Plaister et al.

[ RECIPROCATING FEED MECHANISM [75] Inventors: John Edward Plaister, Bromsgrove;

Raymond Ernest Baugh, Walsall, both of England [73] Assignee: Taylor & Challen Limited,

Birmingham, England [22] Filed: July 19, 1973 [21] Appl. No: 380,868

[30] Foreign Application Priority Data July 21, 1972 Great Britain 34157/72 Sept. 1, 1972 Great Britain 40541/72 [52] US. Cl 214/85 C, 72/422, 214/1 BB [51] int. Cl B2111 43/10 [58] Field of Search..... 214/1 R, 1 BB, 1 BT, 8.5 R, 214/8.5' C; 72/422, 423

Primary Examiner-Frank E. Werner Attorney, Agent, or Firm-Scrivener Parker Scrivener & Clarke [57] ABSTCT This invention relates to a reciprocating feed mechanism of the kind which is suitable for feeding individual blanks between the dies of a coining press and which comprises a reciprocating slide carrying a pair of gripper arms adapted to grip and release the individual blanks. The slide and gripper arms are each operated through a separate linkage mechanism by a respective cam surface on cam means common to both linkage mechanisms, and a sliding connection is pro vided in the linkage mechanism, operating the gripper arms which is such as to allow reciprocation of the slide and gripper arms independently of actual operation of the gripper arms. Each of the blanks which is to be carried is picked-up by the gripper arms at a loading station where the blank lies on a horizontal support surface and is held in the correct position for gripping by the action of a vacuum pump which evacuates air from an aperture in the support surface directly beneath the blank.

6 Claims, 3 Drawing Figures RECIPROCATING FEED MECHANISM This invention relates to a reciprocating feed mechanism of the kind which is suitable for feeding individual blanks between the dies of a coining press and which comprises a reciprocating slide carrying a pair of gripper arms adapted to grip and release the individual blanks.

The present invention consists in a feed mechanism of the above kind in which the slide and gripper arms are each operated through a separate linkage mechanism by a respective cam surface on cam means common to both linkage mechanisms, and in which a sliding connection is provided in the linkage mechanism operating the gripper arms which is such as to allow reciprocation of the slide and gripper arms independently of actual operation of the gripper arms.

Preferably, the linkage mechanism operating the gripper arms comprises a longitudinally reciprocating link which is mounted on fixed support means with the cam means, and a lever which is mounted on the slide and is connected to the longitudinally reciprocating link through said sliding connection which comprises a slider block engaging a transverse groove or slot in the longitudinally reciprocating link. According to a further feature of the invention each of the blanks which is to be carried is picked-up by the gripper arms at a loading station where the blank lies on a horizontal support surface and is held in the correct position for gripping by the action of a vacuum pump which evacuates air from an aperture in the support surface directly beneath the blank.

The invention is now described by way of example with reference to the accompanying drawings in which FIG. 1 is a plan view of a reciprocating feed mechanism according to the invention.

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

FIG. 3 is a cross section along the line 33 of FIG 1.

Support means 1 supports a slide assembly 2 in a horizontal slideway 3 and supports a horizontal cam assembly 4 alongside the slideway so that it can reciprocate the slide 2 through a lever 5. The lever 5 lies below the support means 1 and cam assembly 4 and is pivoted towards its centre on the pivot 6. One end of the lever 5 carries a cam roller 7 which engages in a cam groove 8 in the underside of a lower cam 9 in the cam assembly 4 and the other end of lever 5 is connected to the underside of the slide 2 through a short link 10 which extends along the axis of reciprocation of the slide.

The slide 2 carries a pair of double-armed gripper levers 11 which are pivotally mounted so that each has one arm 12 which extends substantially parallel to the axis of reciprocation of the slide and is adapted to cooperate with-the other arm 12 so as to grip a blank therebetween. Each gripper lever 11 also has one arm 13 which extends outwards from the side of the slide 2 and is pivotally connected through a link 14 to a subslide 15 which is mounted in the slide 2 so as to slide along the same axis of reciprocation as the latter. This arrangement is such that controls opening and closing movement of the gripper arms 11.

Movement of the sub-slide 15 in slide 2 is controlled by a linkage mechanism comprising a longitudinally guided link 16, a bell-crank lever 17 and a link 18. The

link 16 is guided in a housing 19 mounted on the support means 1 and carries a cam roller 20 at one end which engages a cam groove 21 in the upper surface of an upper cam 22 in the cam assembly 4. The other end of the link 16 is formed with a widened portion 23 with a transverse groove 24 in its underside. The bell-crank lever 17 is pivotally mounted on a bracket 25 secured to the slide 2 and has one arm which extends substantially parallel to the axis of reciprocation of the slide 2 and which carries a slider block 26 at its end which engages in the transverse groove 24 in link 16. The other arm of the bell-crank lever 17 extends inwards of the slide 2 and is connected to the sub-slide 15 through the link 18, a cylindrical member 27, a bolt 28 and a spring 29. The link 18 is pivotally connected to the cylindrical member 27, the latter is a slide fit within a bore 30 in the sub-slide 15, the bolt 28 is threaded into the cylindrical member 27, and the spring 29 acts between the sub-slide 15 and bolt 28 so that it is compressed when these connecting members move the sub-slide to close the gripper arms 1 l. The compressed spring 29 thereafter acts to impart a positive gripping force to the gripper arms so that they hold the blanks more securely. Rotation of the bolt 28 permits adjustment of this gripping force.

It will be appreciated that longitudinal movement of the link 16 caused by the cam groove 21 moves the subslide axially, and that this action is completely independent of the position of the slider block 26 in the groove 24 and thus of the position of the slide 2.

The grooves in the two coupled cams 9 and 22 of the cam assembly 4 can be adapted to give the required sequence of movements of the slide 2 and gripper arms 11. In the illustrated arrangement, the gripper arms 11 close on a blank 31 on a horizontal support surface 32 of a member 33 at the bottom of a stacker tube 34, the slide moves forward to transfer the blank to a coining station at which the gripper arms open to release the blank, and the slide then moves back to its original position and the whole cycle repeats. On the forward movement of the slide the leading edges of the gripper arms can be used to engage and eject the blank which has just been coined. Dwell periods in the operation of the slide and gripper arms can be provided as required by suitable shaping of the cam grooves.

Adjustment of the extreme axial positions of the slide 2 at which the gripper arms 11 open and close can be achieved by providing eccentric means on the pivot 6 of lever 5.

Adjustment of the lateral spacing of the gripping ends of the gripper arms 11 can be achieved through the eccentric pivots 35 by which the links 14 are pivotally connected to the sub-slide 15.

In the illustrated feed mechanism the lowermost blank is exposed for engagement by the gripper arms 11 and as a result it can move horizontally under the affect of vibrations. Such movement is limited by the weight of the blanks in the stack above the lowermost one and further the grippers can tolerate slight variations in the lateral position of the lowermost blank whence the feed action is not adversely affected, at least when the feed mechanism operates at lower speeds. However, it has been found that when operating at high speeds such'as required by modern coining presses, slight variations in the lateral position of the lowermost blank can adversely affect the feed action and result in misfeeding which damages the feed mechanism and other parts of the press. This arises because of the quicker movements of the gripper arms which, if the blank is not accurately positioned, will disturb the blank completely so that there is no chance of gripping it correctly.

According to a further feature of the present invention this difficulty is overcome by providing an aperture 36 in the horizontal support surface 32 in a position so that it is completely covered by the lowermost blank 31 when the latter is correctly positioned, and by providing a pump (not shown) to evacuate air from the aperture via connection means 37 so that the lowermost blank is held in position by suction and cannot be moved by normal press vibrations.

Preferably, the pump operates continuously and the gripper arms overcome the suction force to feed the blank laterally, the next blank then falls from the stacker tube 34 onto the horizontal support surface 32 in the correct horizontal position and is almost immediately held in position by the suction force which rapidly builds up. In a typical arrangement which is adapted to handle blanks of Ainch diameter, the aperture 36 in the horizontal support surface is a hole of Ainch diameter.

he i nti ha en de cr bed o e inre a i to an embodiment of the invention in which the blanks are in a stack, but it will be appreciated that the invention is equally applicable to other feed arrangements such as that in which the blanks slide down an inclined chute one after the other edge to edge and are fed from a loading station at the bottom of the chute. In this arrangement the aperture 36 can be provided in the horizontal support surface 32 at the loading station at the bottom of the chute.

We claim:

1. A reciprocating feed mechanism suitable for feeding individual blanks between the dies of a coining press comprising a reciprocating slide, a pair of gripper arms mounted on said slide to grip the individual blanks, cam means having first and second cam surfaces, a first linkage mechanism which includes a cam follower engaging said first cam surface and which is connected to said slide so as to reciprocate the latter as said cam rotates, a second linkage mechanism which includes a cam follower engaging said second cam surface and which is connected to said pair of gripper arms so as to operate the latter as said cam rotates, said second linkage mechanism including a sliding connection which allows the slide and gripper arms to be operated independently.

2. A mechanism as claimed in claim 1 in which said second linkage mechanism comprises a longitudinally reciprocating link which is mounted on fixed support means with the cam means, and a lever which is mounted on the slide, said lever being connected to said longitudinally reciprocating link through said sliding connection which comprises a slider block engaging a transverse groove or slot in the longitudinally reciprocating link.

3. A mechanism as claimed in claim 2 in which a subslide is mounted on the slide so as to move relative to the slide along the axis of reciprocation of the latter, in which said lever is connected to the sub-slide and operates to move the latter relative to the slide, and in which the gripper arms are pivotally mounted on the slide and are connected to the sub-slide.

4. A mechanism as claimed in claim 3 in which said connection between said lever and said sub-slide includes spring means which is compressed and imparts a positive gripping force to the gripper arms when they are operated by the lever to grip a blank.

5. A mechanism as claimed in claim 1 in which the gripper arms grip each of the blanks in turn at a loading station including a substantially horizontal support surface provided with an aperture in a position so that it is completely covered by the blank when the latter is correctly positioned, and in which a pump is provided to evacuate air from the aperture so that the blank is held in position by suction.

6. A mechanism as claimed in claim 5 in which a vertical tube is provided at the loading station and supports a stack of blanks so that the lowermost blank lies on said support surface and has its sides exposed to be gripped by the gripper arms.

Claims

3. A mechanism as claimed in claim 2 in which a sub-slide is mounted on the slide so as to move relative to the slide along the axis of reciprocation of the latter, in which said lever is connected to the sub-slide and operates to move the latter relative to the slide, and in which the gripper arms are pivotally mounted on the slide and are connected to the sub-slide.