GB2240299A

GB2240299A - A workpiece grip

Info

Publication number: GB2240299A
Application number: GB9001719A
Authority: GB
Inventors: Philip Morgan Griffiths
Original assignee: GM ARTS Ltd
Current assignee: GM ARTS Ltd
Priority date: 1990-01-25
Filing date: 1990-01-25
Publication date: 1991-07-31
Also published as: GB9001719D0

Abstract

A workpiece grip comprises a workpiece support 7, an elongated frame 3 extending from the workpiece support 7, a stirrup 14 slidably mounted on the frame 3 remote from the workpiece support 7 and an elongated flexible member 12 having one end secured to an anchor 11 at the workpiece support end of the grip and its other end secured to the stirrup 14. in use, upon application of force to the stirrup 14 to move it away from the support 7, the flexible member 12 is constrained by a guide 13 to clamp a workpiece W to the workpiece support 7, the workpiece (W) then being gripped between the support 7 and the flexible member 12. The gripping action is initiated and can be maintained simply by foot pressure applied by an operator, no adjustment of complicated operating mechanism is required, and the operator has both hands free both for positioning the workpiece and for working upon it. A resilient spring 15 carried by the stirrup may be provided for latching engagement with a frame neck 18 (Fig 4) to retain the stirrup in the strap-tightened condition. The frame length may be telescopically adjustable. In a modification (Fig 5), the grip has a foldable trestle-like form. <IMAGE>

Description

WORKPIECE GRIP This invention relates to a workpiece grip.

According to the present invention there is provided a workpiece grip comprising a workpiece support, an elongated frame extending from the workpiece support, a stirrup slidably mounted on the frame remote from the workpiece support and an elongated flexible member having one end secured to an anchor at the workpiece support end of the grip and its other end secured to the stirrup, the flexible member having one face disposed for engaging a workpiece supported by the workpiece support and having an opposite face disposed to be engaged by a guide that is between the anchor and the stirrup and is disposed such that upon application of force to the stirrup to move the stirrup away from the support the flexible member is constrained to clamp the workpiece to the workpiece support, the workpiece then being gripped between the support and said one face of the flexible member.The gripping action is initiated and can be maintained simply by foot pressure applied by an operator, no adjustment of complicated operating mechanism is required, and the operator has both hands free both for positioning the workpiece and for working upon it.

4 For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a perspective view of a first form workpiece grip, Figure 2 is a perspective view of all but the lowest portion of a second form of workpiece grip, illustrating how the grip is operated, Figure 3A is a diagrammatic sectional side view on a large scale of the detail ringed at III in Figure 2, showing the grip readied for gripping a workpiece and illustrating how the grip is operated, Figure 3B is a view similar to Figure 3A but showing the grip operated to grip the workpiece, Figure 4 is a side view on a larger scale of a further detail of the workpiece grip of Figure 2, also illustrating operation, and Figure 5 is a perspective view of a third form of workpiece grip.

The first and second forms of workpiece grip are for use supported from the ground 1 by any horizontal flat surface 2 that is at a convenient height, for example a table or a workbench.

Each of the first and second forms of grip has an elongated frame 3 which in use extends from the ground 1 to the surface 2 inclined outwardly away from the surface 2 towards the ground 1. The angle of inclination is determined, in the first form of Figure 1, by the angle at which a bent-over upper portion 3' of the frame 3 extends from the remainder of the frame 3, this upper portion 3' constituting a rest for resting on the surface 2. In the form of Figure 2 the frame 3 carries a flat rest 4 that is for resting on the horizontal support surface (not shown in Figure 2) and it is the angle at which this rest 4 projects from the frame 3 that determines the angle of inclination of the grip in use.

The base portion 3" of the frame 3 (shown only in Figure 1) can be telescopically extended or contracted, to suit the frame to the height of the surface 2, by first releasing screw-threaded collars 5, these adjustments being indicated by arrows 6 in Figure 1.

At its top each of the workpiece grips so far described has a workpiece support 7 of lectern formation in which a workpiece W can rest. The rear limb 8 of this support has a solid face interrupted by a slot 9. In each edge of this slot 9 that extends upwardly away from the base of the support there is a groove 10 and in these opposed grooves there are engaged the opposite ends of a bar 11 (Figure 2) which can slide along the grooves 10.

The bar 11 anchors one end of a workpiece retaining strap 12 which is for passing around a workpiece W resting in the support 7, one face of the strap engaging the workpiece. Thereafter the strap 12 passes under a fixed guide bar 13 carried by the frame 3 immediately in front of the frame upper portion 3' (Figure 1) or the plate 4 (Figure 2), this guide bar engaging the opposite face of the strap. From the fixed guide bar 13 the strap 12 extends down to a foot stirrup 14 slidably mounted in the frame near the bottom of the frame.

In the second form of grip, as shown in Figure 4, the stirrup 14 is provided with a latch member 15 of a locking device 16. This latch member 15 consists of a resilient metal sheet bent so as to have as viewed in section (Figure 4) first and second limbs 15A, 15B defining a first V that extends to a second V defined by third and fourth limbs 15C, 15D, from the limb 15D of which extends a fifth limb 15E. The first V 15A/15B is contained with a housing portion 17 of the stirrup 14 such that the resilience of the sheet urges the second V 15C/15D to engage a series of rachet teeth 18 carried by the frame 3. This engagement locks the stirrup 14 against motion up or down the frame 3. Such a locking device could also be provided in the grip of Figure 1, or this device could be omitted from the grip of Figure 2.

Operation of either of the workpiece grips so far described is as follows.

The grip is first rested against a suitable horizontal flat surface that is at a convenient height, such as a table or workbench, the overall length of the frame 3 being adjusted as necessary utilising the telescopic adjustment at the collars 5. With the locking device 16 (if provided) set to hold the stirrup 14 near or at the top of its permitted travel so that the strap 12 is loose (if no locking device 16 is provided the strap 12 is loose as the stirrup 14 is then free to travel up the frame 3), a workpiece W is placed in the support 7 under the run 12A of the strap 12 that is between the bars 11 and 13 (Figure 3A).

As indicated by solid arrows in Figures 2 and 3A downward foot pressure is then applied to the stirrup 14 to tighten the strap 12 about the workpiece W and hold the workpiece gripped against the support 7, the strap 12 being constrained to effect this clamping action by the disposition of the guide bar 13. The workpiece W is held gripped between the support 7 and the strap 12.

If the locking device 16 is not provided, the grip on the workpiece is maintained by continuing to apply foot pressure (solid arrow in Figure 3B). Where the locking device 16 is provided this device is automatically released as the operator places his foot in the stirrup 14, as the limb 15E of the latch member 15 is positioned, as shown in Figure 2, to be engaged by the operator's foot when it is entered in the stirrup.

This engagement has the effect of squeezing the first V 15A/15B to release the second V 15C/15D from its engagement with the ratchet teeth 18, as illustrated by solid arrows in Figure 4, permitting the operator to move the stirrup to apply gripping force to the workpiece. Thereafter, upon removal of the operator's foot from the stirrup 14 the resilience of the latch member 15 asserts itself so that the second V 15C/15D automatically springs back into engagement with the ratchet teeth 18 to lock the stirrup 14 in the workpiece held gripped position.

When it is desired to release the workpiece W the operator either removes his foot from the stirrup 1 4 (when the locking device 16 is not provided and the operator has been maintaining the gripping force himself), or he replaces his foot in the stirrup to release the locking device and hold it released whilst he removes the workpiece.

It is to be noted that, even where provided, the latch member 15 of the locking device 16 can be removed from the housing portion 17 of the stirrup 14, by compressing the first V 15A/15B and drawing the latch member 15 out of the housing portion, so that the grip can be easily placed in a condition where gripping force is maintained solely by the operator.

The third form of workpiece grip shown in Figure 5 is a free-standing form in which the elongated frame 3 is part of a folding trestle, the frame 3 being at the front of this trestle and having two side-by-side but spaced apart portions 3A, 3B in either of which the stirrup 14 can be mounted. A rear frame 19 of the trestle is hinged to the front frame 3 at the top of the trestle. The workpiece support 7 is elongated and has two slots 9A, 9B respectively corresponding with the frame portions 3A and 3B. In the manner already described the strap 12 is mounted either (as illustrated) to extend from the slot 9A to the stirrup 14 mounted in the frame portion 3A, or alternatively it can be mounted in the slot 9B to extend to the stirrup 14 moved to the frame portion 3B. In this way the grip can be set-up to suit a right-handed or a left-handed operator.Alternatively two straps 12 and stirrups 14 could be provided, utilising the slot 9A and frame portion 3A and the slot 9B and frame portion 3B, enabling lengthy workpieces to be gripped at two spaced-apart locations. In this case, at least one of the stirrups 14 and the frame portions 3A, 3B would be provided with a locking device as described above with particular reference to Figure 4.

The workpiece support 7 can be provided with various configurations of holes and slots, such as indicated at 20 in Figure 5, to facilitate working operations on the workpiece.

In use of any of the forms of workpiece grip described above with reference to the Figures, a workpiece can be very quickly positioned and gripped, and quickly released again, the gripping action being initiated (and maintained when no locking device is utilised) simply by the operator applying foot pressure to the stirrup. No adjustment of complicated operating mechanism is required, the operator has both hands free both for positioning the workpiece and for working upon it, and as the gripping action is applied by the flexible strap the risk of damage to the workpiece is minimal. The workpiece configuration is not critical.

The grips are particularly suited to carrying out repeated operations on a series of workpieces.

Although a strap 12 is illustrated and has been described, and is preferred where it is important that the workpiece should not be damaged, any elongated flexible member could be substituted therefor, for example a chain.

Claims

1. A workpiece grip comprising a workpiece support, an elongated frame extending from the workpiece support, a stirrup slidably mounted on the frame remote from the workpiece support and an elongated flexible member having one end secured to an anchor at the workpiece support end of the grip and its other end secured to the stirrup, the flexible member having one face disposed for engaging a workpiece supported by the workpiece support and having an opposite face disposed to be engaged by a guide that is between the anchor and the stirrup and is disposed such that upon application of force to the stirrup to move the stirrup away from the support the flexible member is constrained to clamp the workpiece to the workpiece support, the workpiece then being gripped between the support and said one face of the flexible member.

2. A workpiece grip as claimed in claim 1 and further comprising a releasable locking device for locking the stirrup to the frame in workpiece gripping position.

3. A workpiece grip as claimed in claim 2, wherein the locking device comprises a latching member resiliently urged into cooperation with a series of ratchet teeth.

4. A workpiece grip as claimed in claim 3, wherein the ratchet teeth are provided on the frame and the latching member is carried by the stirrup so as to be engaged to be released from the ratchet teeth by an operator's foot entered in the stirrup.

5. A workpiece grip as claimed in claim 4, wherein the latching member can be removed so as to render the locking device ineffective.

6. A workpiece grip as claimed in any one of claims 1 to 5, wherein at the workpiece support end of the grip there is a rest for resting on a surface to support the grip for use.

7. A workpiece grip as claimed in claim 6, wherein the frame is adjustable in length and means is provided for locking the frame at its selected length.

8. A workpiece grip as claimed in any one of claims 1 to 5, wherein the grip is free-standing, the frame being part of a trestle that carries the workpiece support.

9. A workpiece grip as claimed in claim 8, wherein the elongated flexible member and the stirrup are mountable at either of two spaced-apart locations in the grip to suit either a right-handed operator or a left-handed operator.

10. A workpiece grip as claimed in claim 8, wherein the elongated flexible member and the stirrup are mounted at one location in the grip and a further elongated flexible member and associated stirrup are mounted at a second location in the grip whereby a workpiece can be gripped at two spaced-apart locations.

11. A workpiece grip substantially as hereinbefore described with reference to Figure 1, or Figures 2, 3A, 3B and 4, or Figure 5 of the accompanying drawings.