GB2088265A - Press tool machine - Google Patents

Abstract

A press tool machine particularly for flaring end portions of metal tubes comprises a frame (6), a pressing assembly (14) adapted to carry a pressing tool (48) mounted on the frame, gripper support devices (36, 38) mounted on the frame, and gripper members (32) carried by the gripper support devices. In the use of the machine, a workpiece is inserted between the gripper members, and the pressing assembly (14) is moved so that engagement by the pressing tool (48) with the gripper members causes the gripper members to move towards each other into a first condition to grip the workpiece. When in such first condition, a retractable catch plate (52) prevents movement of the gripper members from said first condition. Thereafter, the machine is operated to carry out a flaring operation on the workpiece clamped between the gripper members. On a specific retraction of the pressing assembly, cams retract the catch plate. <IMAGE>

Description

SPECIFICATION Improvements relating to press tool machines Description of the Invention This invention is concerned with improvements in or relating to press tool machines, for carrying out a pressing operation on a workpiece and particularly of the kind (hereinafter referred to as being of the kind specified) comprising a frame, a pressing assembly adapted to carry a pressing tool mounted on the frame, gripper support devices mounted on the frame, gripper members carried by the gripper support devices, and means to cause relative movement between the pressing assembly and a pressing tool carried thereby and the gripper support devices and gripper members carried thereby, to cause relative movement between the gripper members and the gripper support devices, such relative movement in one direction causing the gripper members to move towards each other into a first condition to grip a workpiece there between.

A press tool machine of the kind specified is described in the Specification of our U.K. Patent No. 1,571,822 which is particularly adept in flaring end portions of metal tubes. In this machine, the gripper support members are afforded by posts, and the gripper members are provided with cam surfaces, arranged in a manner such that relative movement in said one direction between the support posts and the gripper members causes the gripper members to move to their first condition.

One of the problems encountered in press tool machines of the kind specified is that in the flaring of tubes to a particular design, in particular one in which the flared portion comprises a parallel-sided cylindrical portion, when the pressing assembly is moved to carry the pressing tool away from the workpiece, the tool tends to carry the workpiece with it. In the machine described in our above numbered Patent, this causes the gripper members to move away from one another, to release the workpiece, and requires a manual release of the workpiece from the pressing tool.

According to a first aspect of this invention there is provided a press tool machine comprising a frame, gripper support devices mounted on the frame; a pressing assembly mounted on the frame for longitudinal movement relative to the gripper support devices; and gripper members carried by the support devices for relative movement thereto, movement of the gripper members in a first longitudinal direction relative to the support devices causing the gripper members to move towards one another into a first condition, to grip a workpiece inserted therebetween, and movement of the gripper members in a second longitudinal direction relative to the support devices causing the gripper members to move away from one another into a second condition, to release a gripped workpiece, or to enable a workpiece to be inserted between the gripper members, the gripper members moving into said first condition in consequence of longitudinal movement of the pressing assembly relative to the gripper support devices in a first direction, wherein means is provided to restrain movement of the gripper members in said second longitudinal direction.

Preferably said means is operative in consequence of movement of the gripper members into said first condition, whereby to restrain movement of the gripper members in said second longitudinal direction, and in consequence separative movement of the gripper members, whilst the pressing assembly is retracted from the gripper members. This will permit a pressing tool to be carried by the pressing assembly to be withdrawn from a workpiece gripped by the gripper members, subsequent to which said means may be caused to release the gripper members for such movement in said second longitudinal direction.

Conveniently said means is rendered operative to so release the gripper members in consequence of a specific retracted movement of the pressing assembly relative to the gripper support devices.

According to another aspect of this invention.

there is provided a press tool machine of the kind specified, in which the gripper support devices are secured to the frame of the machine and are provided with cam surfaces with which the gripper members, or parts secured thereto, engage, said cam surfaces being arranged in a manner such as to cause relative movement of approach between the gripper members on relative movement between the gripper support devices and said gripper members in said one direction.

By providing the cam surfaces on the gripper support devices, which are themselves secured to the frame, the gripper support devices may be of plate-like form enabling them to be produced relatively inexpensively.

Thus, most conveniently the gripper support devices are of plate-like form, provided with a number of slots into which parts (e.g. support posts of) the gripper members extend, the slots affording the cam surfaces and being arranged to cause movement of the gripper members towards one another when the gripper members are moved relative to the pressing assembly.

Thus, the gripper support devices may each be afforded with two pairs of convergent slots.

To provide a high degree of strength, each gripper support device may be afforded by two or more plates secured together in the form of laminations. In this manner, the slots may be provided in the plates by a punching operation without undue strength in the punching tool, and without any reduction in the accuracy of the slots, the surfaces afforded by the slots of all the plates of each device co-operating to provide the required strength.

There will now be given a detailed description, to be read with reference to the accompanying drawings, of a press tool machine which is a preferred embodiment of this invention and which has been selected for the purposes of illustrating the invention by way of example.

In the accompanying drawings: FIGURE 1 is a perspective view of the illustrative machine from above, part being broken away for clarity; and FIGURE 2 is a perspective view of part of the machine from below, parts similarly being broken away for clarity.

The machine which is the preferred embodiment of this invention comprises a frame 6 comprising a base plate 8, a top plate 10, and side plates 12, 12. Slidably mounted within the frame is a pressing assembly 14 which comprises side members 16, 16, slidable in contact with the side plates of the frame, a head 1 8 at one end, the head being afforded with a slot 19, and a tail 20 at the other end, the tail being afforded with a circular bore 21.

The machine also comprises drive means 24 afforded by a screw 26 threadedly received in a boss 28 at one end of the frame, a leading end portion of the screw 26 being journalled in the head 1 8 of the pressing assembly. By rotation of the screw 26, conveniently by means of a handle 30, the pressing assembly may be moved relative to the frame between the side plates 12 thereof in a direction longitudinally of the machine.

The machine also comprises two gripper members 32, only one of which is shown (Figure 1), afforded by split clamping dies, each gripper member comprising four support posts 34, two extending upwardly, as shown in Figure 1, and two extending in line therewith, downwardly, not shown. The machine also comprises upper and lower gripper supporting devices 36 and 38 respectively, the lower gripper support device being secured to the base plate 8 of the frame, and the upper gripper support device being mounted on bolts 40 secured to outflanged margins 13 of the side plates 12, so as to extend over a central aperture 1 1 of the top plate 1 0.

Each of the upper and lower gripper support plates comprises two pairs of slots 42, each pair of slots comprising a convergent portion 44 and a portion 46 which extends substantially parallel to the longitudinal axis of the frame, said longitudinal portion 46 extending from the convergent portion 44 on the side thereof closest to the tail 20 of the machine.

The two gripper support members are of platelike form, the upper gripper member comprising four laminations, the lowermost of which is not provided with slots, whilst the lower gripper support device is provided by two plates secured together.

In the mounting of the gripper members on the machine, the upper device 36 is removed by removal of the wing nuts 41 from the bolts 40, and the two gripper members are placed on the lower gripper support device with lower support posts extending through the slots thereof. One gripper member is shown in such a position on the lower gripper support device in Figure 1 and it will be appreciated that the other gripper member is mounted in a similar manner, with the die formation thereof facing that of the first said gripper member.

The upper gripper support plate is then mounted on the bolts 40, the support posts 34 extending upwardly into the slots 42 thereof, and the device 36 is secured by the wing nuts in position.

It will thus be appreciated that movement of the gripper members in a longitudinal direction towards the tail 20 will effect movement of the gripper members towards one another, whilst movement of the gripper members in a direction longitudinally away from the tail will cause the gripper members to separate.

The manner of operation of the machine tool which is the preferred embodiment of this invention is similar in certain aspects, to that the subject of our aforementioned U.K. Patent, to which reference may be made for details not included herein. However, in the operation of the preferred embodiment, with the gripper members in a second condition, in which they are separated, a workpiece which may be in the form of a motor vehicle brake pipe, is inserted through the bore 21 of the tail 20, between the two gripper members 32, so as to project forwardly therefrom.With a stop tool 48 in the slot 19 of the head, the screw 26 is rotated to move the pressing assembly in a first longitudinal direction (generally from right to left in Figure 1) to carry the stop tool 48 firstly into engagement with the brake pipe, to push the brake pipe rearwardly, until the stop tool 48 engages the front face of the gripper members. At this point, the stop tool ceases to move the brake pipe relative to the gripper members, but continues to move both the gripper members and the brake pipe in said first longitudinal direction, and in particular causes movement of the gripper members relative to the gripper support devices, so that movement of the support posts 34 in the slots 42 causes the gripper members to be moved towards one another, to clamp around the brake pipe.The support posts 34 then enter the longitudinal portions 46 of the slots as the gripper members move into positions defined by rear ends of the slots 42.

Movement of the screw 26 is reversed, to withdraw the head 18 from the gripper members, a distance sufficient to enable the stop tool 48 to be removed from the slot 19, and replaced by a pressing tool. The head is then advanced once more towards the gripper members, and the pressing tool enters the brake pipe, to flare the end portion thereof as determined by the profile of the gripper members and the pressing tool.

The head once more is retracted, by movement of the pressing assembly in the opposite longitudinal direction, until the tail engages the gripper members, moving the gripper members relative to the gripper support devices, the support posts 34 travelling along the longitudinal portions 46 of the slots 42, and the gripper members moving apart when the posts 34 enter the portions 44 of the slots.

The brake pipe may then be removed from the machine, the pressing tool replaced by the stop tool, and a further workpiece inserted into the machine for a pressing operation.

To avoid in certain flaring operations, the workpiece being retained in engagement with the pressing tool on movement of the pressing assembly in said opposite longitudinal direction, the machine is provided with means to restrain movement of the gripper members during an initial part at least of movement of the pressing assembly in said opposite longitudinal direction.

Thus the machine comprises a catch plate 52 mounted on the base plate 8. A rear end of the catch plate is provided with a tongue 54, which is received within a complementary aperture 56 of a support plate 58, secured to the base plate. At its opposite end, the catch plate is provided with an upwardly extending catch portion 60.

The engagement of the tongue 54 within the aperture 56 permits the catch plate 52 to undergo some degree of tilting movement (viz, up and down movement of the catch portion 60) and the catch plate is urged into an upper position by spring means, afforded by a spring plate 62 secured to the underside of the base of the frame and which extends through an aperture in the base plate 8 into engagement with a forward portion of the catch plate 52.

When in its upper position, the catch portion extends upwardly beyond the level of the upper surface of the lower gripper support device.

However, on movement of the pressing assembly in said second direction, cam surfaces 17 on the undersides of the side members 16 engage side lugs 53 of the catch plate, moving the catch plate downwardly, and causing the catch portion 60 to move beneath the level of the upper surface of the lower gripper support device 38.

Thus when the gripper members are mounted on the gripper support devices, the catch plate 52 will initially be depressed by the presence of the gripper members, into its lower position. However, on rearward movement of the gripper members into the position shown in Figure 1 ,just prior to the gripper members reaching their rearmost positions, the catch plate is freed to move into its upper position, with the catch portion 60 in a position to prevent forward movement (viz, second longitudinal direction) of the gripper members.

Thus on completion of an operation to flare a motor vehicle brake pipe, on retraction of the head and pressing tool, movement of the gripper members 32 in said second longitudinal direction is prevented and the movement of the head will be effective to withdraw the pressing tool from the workpiece. Subsequently as the cam surfaces 17 engage the side lugs 53 of the catch plate, the catch plate will be depressed, prior to engagement of the gripper members by the tail 20 which will effect opening movement of the gripper members.

Claims (12)

1. A press tool machine comprising a frame, gripper support devices mounted on the frame; a pressing assembly mounted on the frame for longitudinal movement relative to the gripper support devices; and gripper members carried by the support devices for relative movement thereto, movement of the gripper members in a first longitudinal direction relative to the support devices causing the gripper members to move towards one another into a first condition, to grip a workpiece inserted therebetween, and movement of the gripper members in a second longitudinal direction relative to the support devices causing the gripper members to move away from one another into a second condition, to release a gripped workpiece, or to enable a workpiece to be inserted between the gripper members, the gripper members moving into said first condition in consequence of longitudinal movement of the pressing assembly towards the gripper support devices wherein means is provided to restrain movement of the gripper members in said second longitudinal direction.

2. A press tool machine according to Claim 1 wherein said means is operative in consequence of movement of the gripper members into said first condition, whereby to restrain movement of the gripper members in said second longitudinal direction from said first condition during movement of the pressing assembly away from said gripper support devices.

3. A press tool machine according to Claim 2 wherein said means is releasable, and subsequent to such movement of the pressing assembly away from the gripper support devices, said means may be caused to release the gripper members for such movement in said second longitudinal direction.

4. A press tool machine according to Claim 3 wherein said means is rendered operative to so release the gripper members in consequence of a specific retractive movement of the pressing assembly relative to the gripper support devices, subsequent retractive movement of the pressing assembly causing the gripper members to move into said second condition.

5. A press tool machine according to any one of the preceding claims wherein said means comprises a catch member which is urged into a position in which it is operative to prevent movement of the gripper members from said first condition, but is caused to retract from such position on a specific retractive movement of the pressing assembly.

6. A press tool machine according to any one of the preceding claims in which the gripper support devices are secured to the frame of the machine and are provided with cam surfaces with which the gripper members, or parts secured thereto, engage, said cam surfaces being arranged in a manner such as to cause relative movement of approach between the gripper members on relative movement between the gripper support devices and said gripper members on movement thereof in said first longitudinal direction.

7. A press tool machine comprising a frame, a pressing assembly adapted to carry a pressing tool mounted on the frame, gripper support devices mounted on the frame, gripper members carried by the gripper support devices, and means to cause relative movement between the pressing assembly and the gripper support devices to cause relative movement between the gripper members and the gripper support devices, such relative movement in one direction causing the gripper members to move towards each other into a first condition to grip a workpiece therebetween, wherein the gripper support devices are provided with cam surfaces with which the gripper members, or parts secured thereto, engage, said cam surfaces being arranged in a manner such as to cause relative movement of approach between the gripper members on relative movement between said gripper members and said gripper support devices in said one direction.

8. A press tool machine according to one of Claims 6 and 7 wherein the gripper support devices are of platelike form.

9. A press tool machine according to Claim 8 wherein the gripper support devices are provided with a number of slots into which parts of or provided on the gripper members extend, said slots affording the cam surfaces and being arranged to cause movement of the gripper members towards one another when the gripper members are moved relative to the pressing assembly.

10. A press tool machine according to one of Claims 8 and 9 wherein each gripper support device is afforded by two or more plates secured together in the form of laminations.

11. A press tool machine constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.

12. Any novel feature or novel combination of features hereinbefore described and/or shown in the accompanying drawings.