GB1586459A

GB1586459A - Workpiece clamp

Info

Publication number: GB1586459A
Application number: GB4140176A
Authority: GB
Original assignee: ECO WHEEL CO Ltd
Current assignee: ECO WHEEL CO Ltd
Priority date: 1977-11-08
Filing date: 1977-11-08
Publication date: 1981-03-18

Description

(54) WORKPIECE CLAMP (71) We, ECO WHEEL COMPANY LIMITED, a British Company, of Radnor Park Trading Estate, Back Lane, Congleton, Cheshire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention concerns a clamp apparatus for holding workpieces such as rough castings.

Upon removal of a casting from its mould, it is necessary to remove flashings and surplus moulding material from the casting. This requires the casting to be securely held, which in turn may require the making of a special support adapted to the shape of the casting.

An object of the present invention is to provide a clamp apparatus for securely holding workpieces of any shape.

With this object in view the present invention provides a clamp apparatus comprising a bed formed by a plurality of juxtaposed arms pivotally mounted in a frame for independent adjustment to cradle an underside of a workpiece placed on the bed, each arm being lockable in position, and a draw mechanism operative to tighten a flexible member, when placed about the workpiece, to secure the workpiece against the bed.

A locking mechanism may be provided for locking the arms in any position.

The frame supporting the arms may be mounted for adjustment of its position along two sets of slides disposed at right angles.

Means such as an hydraulic jack or a third set of slides may be provided to permit height adjustment of the frame.

Furthermore, a turntable may be provided to permit rotation of the frame about a substantially vertical axis.

Preferably the slides and/or the turntable have pneumatic bearings which effect cleaning of respective slideways.

The frame may be positioned to a light beam set up from above.

An embodiment of the invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a front end view of a preferred embodiment of clamp apparatus in accordance with the invention; Figure 2 is a plan view thereof; Figure 3 is a detail showing one of a plurality of locking devices for swingable arms of the apparatus; and Figure 4 is a side view of the apparatus.

The exemplified embodiment of clamp includes a parallelopiped frame 11 mounted on two sets of slides 12 and 13 disposed substantially horizontally and at right angles. Mounted on the upper slide 13 so as to support the frame 11 is a turntable 14, so that provision is made for both planar and rotational adjustment of the position of the frame 11. The slides 12 and 13 and the turntable 14 have pneumatic bearings which effect cleaning of the respective slideways.

The upper parallelogram 11a of the frame 11 is crossed by a number of bars 11b (Fig.

2) whose outer ends are welded or otherwise secured to alternate sides of the frame 11, so that the top 11a of the frame 11 has a slotted grid formation. Passing centrally through this grid formation, i.e. transversely through the bars lib so as to support the inner ends thereof, is a drawbar 15 on which a plurality of juxtaposed arms 16 are swingably mounted. These arms 16 are so designed that they have one end 16a heavier than the other 16b so that they are biased to swing towards an upright position with their ends 16b uppermost. The arms 16, however, can be held in a substantially horizontal position so as to lie substantially flush with the bars lib and form therewith a flat bed for receiving thereon a workpiece 17, the arms 16 when in this position being arranged with their heavy ends 16a raised alternately to opposite sides the frame 11. The arms 16 are held in this position by a plurality of locking devices 18 mounted in pairs on opposite side edges of the upper frame part 11a for engagement with the ends of respective groups (in the exemplified embodiment groups of three) of the arms 16. As most clearly shown in Figure 3, the locking devices 18 each comprise a T-piece 19 whose stem portion is pivotally mounted by a bolt 20 between a pair of supports 21 welded or otherwise secured to the upper frame part lla. At least one, preferably two, spring washers 22 are interposed between the stem of the T-piece 19 and the supports 21 to provide a thrust bearing against the sides of the stem. The thrust applied by the washer(s) 22 is sufficient to retain the T-piece 19 in a locking position in which the ends 16b of the arms 16 are held horizontal against their tendency to swing upright, whilst enabling the T-piece 19 to readily swung outwardly to free the respective group of arms 16.

In use, the clamp is set up with the swingable arms 16 horizontal as described above. After placing a workpiece on the bed, selected locking devices 18 are swung outwardly of the frame 11 to free respective groups of arms 16 disposed below the workpiece 17. Upon such release, the arms 16 swing about the drawbar 15 towards an upright position until they are restrained by contact with an underside or side of the workpiece 17. Thus the released arms 16 automatically assume a generally V-shaped configuration, adapted to the underside shape of the workpiece 17, which cradles the underside of the workpiece 17. The arms 16 are then locked in their assumed positions by a pneumatic locking mechanism 27 acting with the drawbar 15 to tighten the arms 16 against each other and against the bars lib.

A chain 23 or the like flexible member, having one end anchored to the frame 11, is then placed over the workpiece 17 and is attached at any convenient point along its free length to a lever arm 25 of a pneumatic draw mechanism 24 which tightens the chain around the workpiece 17 to hold it securely against the inclined arms 16 of the bed upon actuation of a pneumatic cylinder 26 mounted on a lower part 1 ic of the frame 11. After the required work has been carried out on the workpiece 17, it is removed by releasing the chain 23 and lifting from the arms 16, leaving the arms 16 in their inclined positions in readiness for receiving a further identical workpiece 17.

In the case of a generally flat workpiece, it is preferable to position the workpiece in a vertical plane. In such a case it may be necessary to release only two or three arms 16 to support the underside (i.e. the side edges) of the workpiece which, because of its shape, would then be unstable. To avoid this, further arms 16 are released to form a back support against which the workpiece is then held by the chain 23.

From the foregoing it will be appreciated that the bed, by means of the swingable arms 16, is adaptable to any underside shape and size of workpiece, and that the chain 23 also adapts to any upper shape and size of workpiece. Additionally the frame 11, once the workpiece is secure, is movable both in a horizontal plane and rotationally about a vertical axis so as to give a good range of adjustment of the position of the secured workpiece.

It will be appreciated that detail modifications may be made to the exemplified embodiment without departing from the scope of the invention. For example, an additional set of slides may be vertically arranged to provide for raising and lowering of the upper part 11a of the frame 11, or hydraulic jacks may be provided for the same purpose. Furthermore, a light source may be provided above the frame 11 for producing a light beam or light line against which the frame 11 may be positioned to facilitate accurate setting of the apparatus.

WHAT WE CLAIM IS: 1. A clamp apparatus comprising a bed formed by a plurality of juxtaposed arms pivotally mounted in a frame for independent adjustment to cradle an underside of a workpiece placed on the bed, each arm being lockable in position, and a draw mechanism operative to tighten a flexible member, when placed about the workpiece, to secure the workpiece against the bed.

2. An apparatus as claimed in Claim 1, in which the flexible member forms part of the apparatus.

3. An apparatus as claimed in Claim 1 or 2, in which the frame supporting the arms is mounted for adjustment of its position along two sets of slides disposed at right angles.

4. An apparatus as claimed in Claim 1, 2 or 3, in which means are provided to permit height adjustment of the frame.

5. An apparatus as claimed in any preceding claim, in which a turntable is provided to permit rotation of the frame about a substantially vertical axis.

6. An apparatus as claimed in Claim 3, 4 or 5, in which the slides and/or the turntable have pneumatic bearings which effect cleaning of respective slideways.

7. An apparatus as claimed in any preceding claim, in which the frame may be positioned to a light beam set up from above.

8. A clamp apparatus constructed and arranged substantially as herein described

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

16 when in this position being arranged with their heavy ends 16a raised alternately to opposite sides the frame 11. The arms 16 are held in this position by a plurality of locking devices 18 mounted in pairs on opposite side edges of the upper frame part 11a for engagement with the ends of respective groups (in the exemplified embodiment groups of three) of the arms 16. As most clearly shown in Figure 3, the locking devices 18 each comprise a T-piece 19 whose stem portion is pivotally mounted by a bolt 20 between a pair of supports 21 welded or otherwise secured to the upper frame part lla. At least one, preferably two, spring washers 22 are interposed between the stem of the T-piece 19 and the supports 21 to provide a thrust bearing against the sides of the stem. The thrust applied by the washer(s) 22 is sufficient to retain the T-piece 19 in a locking position in which the ends 16b of the arms 16 are held horizontal against their tendency to swing upright, whilst enabling the T-piece 19 to readily swung outwardly to free the respective group of arms 16.

In use, the clamp is set up with the swingable arms 16 horizontal as described above. After placing a workpiece on the bed, selected locking devices 18 are swung outwardly of the frame 11 to free respective groups of arms 16 disposed below the workpiece 17. Upon such release, the arms 16 swing about the drawbar 15 towards an upright position until they are restrained by contact with an underside or side of the workpiece 17. Thus the released arms 16 automatically assume a generally V-shaped configuration, adapted to the underside shape of the workpiece 17, which cradles the underside of the workpiece 17. The arms 16 are then locked in their assumed positions by a pneumatic locking mechanism 27 acting with the drawbar 15 to tighten the arms 16 against each other and against the bars lib.

A chain 23 or the like flexible member, having one end anchored to the frame 11, is then placed over the workpiece 17 and is attached at any convenient point along its free length to a lever arm 25 of a pneumatic draw mechanism 24 which tightens the chain around the workpiece 17 to hold it securely against the inclined arms 16 of the bed upon actuation of a pneumatic cylinder 26 mounted on a lower part 1 ic of the frame 11. After the required work has been carried out on the workpiece 17, it is removed by releasing the chain 23 and lifting from the arms 16, leaving the arms 16 in their inclined positions in readiness for receiving a further identical workpiece 17.

In the case of a generally flat workpiece, it is preferable to position the workpiece in a vertical plane. In such a case it may be necessary to release only two or three arms 16 to support the underside (i.e. the side edges) of the workpiece which, because of its shape, would then be unstable. To avoid this, further arms 16 are released to form a back support against which the workpiece is then held by the chain 23.

From the foregoing it will be appreciated that the bed, by means of the swingable arms 16, is adaptable to any underside shape and size of workpiece, and that the chain 23 also adapts to any upper shape and size of workpiece. Additionally the frame 11, once the workpiece is secure, is movable both in a horizontal plane and rotationally about a vertical axis so as to give a good range of adjustment of the position of the secured workpiece.

It will be appreciated that detail modifications may be made to the exemplified embodiment without departing from the scope of the invention. For example, an additional set of slides may be vertically arranged to provide for raising and lowering of the upper part 11a of the frame 11, or hydraulic jacks may be provided for the same purpose. Furthermore, a light source may be provided above the frame 11 for producing a light beam or light line against which the frame 11 may be positioned to facilitate accurate setting of the apparatus.

WHAT WE CLAIM IS: 1. A clamp apparatus comprising a bed formed by a plurality of juxtaposed arms pivotally mounted in a frame for independent adjustment to cradle an underside of a workpiece placed on the bed, each arm being lockable in position, and a draw mechanism operative to tighten a flexible member, when placed about the workpiece, to secure the workpiece against the bed.
2. An apparatus as claimed in Claim 1, in which the flexible member forms part of the apparatus.
3. An apparatus as claimed in Claim 1 or 2, in which the frame supporting the arms is mounted for adjustment of its position along two sets of slides disposed at right angles.
4. An apparatus as claimed in Claim 1, 2 or 3, in which means are provided to permit height adjustment of the frame.
5. An apparatus as claimed in any preceding claim, in which a turntable is provided to permit rotation of the frame about a substantially vertical axis.
6. An apparatus as claimed in Claim 3, 4 or 5, in which the slides and/or the turntable have pneumatic bearings which effect cleaning of respective slideways.
7. An apparatus as claimed in any preceding claim, in which the frame may be positioned to a light beam set up from above.
8. A clamp apparatus constructed and arranged substantially as herein described

with reference to and as illustrated in the accompanying drawings.