GB2316119A - Beam clamp - Google Patents

Abstract

A clamp is provided for attachment to an elongate member such as an I-section beam 10, the clamp comprising a pair of jaws 14, 16, relatively moveable towards one another to embrace the elongate member and clamp the elongate member between the jaws with a given pressure, the jaws being such that if force is applied to the clamp intending the move the jaws in any direction, the said given pressure increases. Preferably one jaw comprises a cam member 27 mounted for universal pivotal movement, movement of the jaw with respect to the elongate member causing the cam member 27 to rotate in the direction which reduces the distance between the jaws. The clamp of the invention is easily mounted and is resistant not only to vertical loads, but also to side loads tending to slide the clamp along the length of the beam 10.

Description

CLAMPING DEVICES The invention relates to clamping devices.

Clamping devices are known, for example to provide an anchorage point on an overhead eye section beam. An example of such a clamping device is shown in International Patent application number PCT/GB 91/02056.

The known clamping device has been specifically designed to resist not only a vertical load, but also a side load tending to slide the clamping device along the length of the beam.

We have now developed an even more versatile clamping device, capable of providing substantial resistance to loads in any direction.

According to a first aspect of the invention, a clamp is provided for attachment to an elongate member such as an I-section beam, the clamp comprising a pair ofjaws relatively moveable towards one another to embrace the elongate member and clamp the elongate member between the jaws with the given pressure, the jaws being such that if a force is applied to the clamp tending to move the jaws in any direction, the said given pressure increases.

When the clamp is arranged for attachment to an I-section beam, the jaws are preferably arranged to grip the central web of the beam, rather than to grip the flanges of the beam.

One of the jaws may comprise a cam member mounted for universal pivotal movement, movement of the jaw with respect to the elongate member causing the cam member to rotate in the direction which reduces the distance between the jaws.

The cam member may be provided with a plurality of concentric gripping ribs.

The other jaw may also be provided with a plurality of concentric gripping ribs.

Another disadvantage of the clamp described in International application number PCT/GB 91/02056 is that the clamp, which is very heavy, has to be held in an overhead position while the jaws are tightened around the beam. This is a difficult operation to be carried out by one person.

A preferred version of the present invention has a further advantage in that the jaws may be mounted on a body member which can be rapidly locked into position around the beam, to support the clamp in an overhead position while final tightening of the jaws takes place.

The jaws may be mounted on limbs which can be pivoted to a position in which they embrace the beam and can then be locked in that position, for example by means of a spring loaded locking pin.

Final tightening of the jaws may be carried out by means of a threaded rod, for example rotatable by means of a tommy bar.

The body member is preferably shaped to have an anchorage point which lies closely adjacent to the beam when the clamp is in its operating position, thus reducing the leverage that can be applied by a load.

By way of example, a specific embodiment of the invention will now be described with reference to the accompanying drawings, in which : Figure 1 is a side view of an embodiment of clamp according to the invention, shown attached to an overhead beam; Figure 2 is a view similar to Figure 1 but showing a preliminary stage in the mounting of the clamp on the beam; Figure 3 is a partial view in the direction of arrow III of Figure 1; Figure 4 is a view of the gripping face of one of the jaws of the clamp; Figure 5 is a cross-section on line V-V of Figure 4; Figure 6 is a view of the face of a second jaw of the clamp; Figure 7 is a cross-section on line VII-VII of Figure 6; and Figure 8 is a view similar to Figure 1 but showing an alternative embodiment to the invention; Figure 9 is a view similar to Figure 3 but showing the alternative embodiment; Figure 10 is a plan view of the second embodiment; Figure 10a is a view similar to Figure 4 but showing the second embodiment; Figure 11 is a view similar to Figure 5 but showing the second embodiment; Figure 12 is a detail of the component shown in Figure 11, to a larger scale; Figure 13 is a view similar to Figures 1 and 8 but showing a third embodiment; Figure 14 is a side view of the third embodiment; Figure 15 is a partial plan view of the split collet shown in Figure 13; Figure 16 is a partial side view of the split collet shown in Figure 13; and Figure 17 is a side view of yet another embodiment.

The clamp shown in Figures 1 to 7 is intended to provide a load attachment point on an overhead beam 10. The clamp is robust, capable of resisting a load applied at any angle, but is nevertheless easy to use, light in weight, and cheap to manufacture.

The body of the clamp comprises a body member 11 having a lower, load supporting limb 12 of a size to extend right underneath a lower flange 13 of the beam 10. The body member 11 also has an upper retaining limb 14.

Pivotally attached to the limb 12 at 15 is a second retaining limb 16.

Each of the components 11 and 16 is manufactured by welding two identically shaped plates to intermediate spacers. The side plates 1 6a and 1 6b of component 16 can clearly be seen in Figure 3.

The limb 16 is pivotable between the position shown in Figure 1, in which the clamp is located around the beam, and the position shown in Figure 2, in which the clamp can be fitted onto, or removed from, the beam.

When the clamp is moved into the configuration shown in Figure 1, a locking pin 17 engages in an aperture 18 in the component 12 to retain the limb 16 in the position shown in Figure 1.

The lockir.g pin 17 is urged into its locking position by a compression spring 19 which acts within a hollow boss 20 welded to the plate 16a.

To attach or remove the clamp, the locking pin 17 can be retracted out of the aperture 18 by means of a central shaft 21 which is attached to the locking pin at one end and to an end cap 22 at the other end. The locking pin is retracted by firmly grasping the end cap 22 and pulling against the action of the compression spring.

The limb 14 supports a first jaw 23 pivotally connected to the limb 14 about a horizontal axis 24. The jaw has a face component 25 which is best shown in Figures 4 and 5. The component comprises a generally square block with the series of concentric ribs 26 thereon.

The movable limb 16 carries a second, opposing jaw 27. The jaw 27 is best shown in Figures 6 and 7. The jaw comprises a disc like member 28 which has a spherical component 29 at one side and slightly concave face 30 at the other side. The concave face 30 has a series of annular ribs 31 similar to the ribs 26 of the jaw 23.

The jaw 27 is mounted for universal pivotal movement, since the spherical portion 29 is captive in a spherical socket 32 at the end of an adjusting rod 33, the other end of the adjusting rod 33 being provided with a tommy bar 34. The rod 33 has a screw threaded portion 35 which cooperates with an internally screw threaded block 36 which is welded between the plates 16a and 16b (see Figure 3).

With many other clamps arranged to be fitted on to overhead beams, the clamp has to be physically supported by an operator while jaws are tightened around the beam. The tightening is usually a slow process, involving the rotation of a screw threaded rod.

With the clamp shown in Figures 1 to 7, a clamp can almost instantly be fitted into a secure position by withdrawing the locking pin 17, flipping the limb 16 into the position shown in Figure 2, fitting the limb 14 around one side of the lower flange of the beam, and flicking the limb 16 back into the position shown in Figure 1, in which the locking pin springs back into the locking position. Thus, the clamp only has to be physically supported by the operator for a few seconds.

The clamp can finally be tightly secured to the beam 10 by rotation of the locking bar 33 using the tommy bar 34.

A load can then be attached to the clamp using an aperture 37 provided in the limb 12.

The clamp will resist substantial loads supplied at almost any angle.

A considerable amount of support is provided by the way in which the clamp very closely embraces the cross-sectional profile of the beam 10 and its lower flange 13. The arrangements and location of the lower limb 12, and the attachment aperture 37, means that the distance between the aperture 37 and the beam 10 is kept to a minimum, thus reducing the leverage effect that any load has on the working parts of the clamp.

Because the working face of the jaw 27 is slightly convex, and the jaw can pivot universally as a result of the spherical portion 29 and socket 32, any tendency for the clamp to move, in any direction, causes the head 27 to pivot slightly, producing a cam effect tending to increase the grip of the clamp on the beam 10. Grip is further improved by the use of the concentric ribs 26 and 31 on the working faces of the jaws.

Turning now to Figures 8 to 12, an alternative embodiment of clamp is shown, which is generally similar to the first embodiment, and similar parts are indicated by similar reference numerals.

The clamp of the second embodiment differs slightly in the following respects.

The side limbs, for example the limb 14 shown clearly in Figures 8 and 10, is manufactured from slightly thinner side plates, but with adequate central bracing shown at 14a.

To facilitate assembly, the part spherical portion 29 of the jaw 27 is held in position by an appropriately internally shaped split collet 29a which is secured within a hollow end of adjusting rod 33 by means of a split pin 29b (see Figure 10).

To assist in retaining the jaw 27 in the central position shown in the Figures, during adjustment of the clamp, a compression spring 29c is added which acts between the rear face of the jaw 27 and a portion of the adjusting rod 33.

The diameter of the head 22 of the locking pin is increased, to facilitate easier extraction of the locking pin when it is desired to move the clamp to the release or attachment position shown in Figure 2.

The jaw 23, instead of being pivotally connected to the limb 14, is rigidly fixed to the limb 14 by means of two bolts 23a (see Figure 8) which extend through two holes 23b in the jaw (see Figure 11).

The attachment aperture 37 is made circular in the second embodiment, as can be seen from Figure 8.

Figure 13 shows a further possible embodiment of clamp, which is generally similar to the second embodiment, and similar parts are indicated by similar reference numerals.

The third embodiment differs slightly in the following respects.

The side limbs 14 and 16 are shaped so that they bear against the flange 13 of the beam 10 at points considerably closer to the web than is the case in the first and second embodiments. This reduces any twisting force on the beam 10 when the clamp is subjected to an angle load. The contact areas are shown at 38 and 39.

The split collet 29a, which can be seen in greater detail in Figure 15 and 16 additionally comprises a flange 29d which serves the dual purpose of providing a larger area of material to retain the compression spring 29c in its correct location and also of restraining the split collet 29a from moving too far into the adjusting rod 33. If the split collet 29a were to move too far into the adjusting rod 33 then it would not be possible to insert the split pin 29b (Figure 10) into its opening as is required for the proper functioning of the clamp.

Turning now to Figure 17, there is shown a further embodiment of the clamp having a longer adjusting rod 33 and a longer screw threaded portion 35. This is to accommodate an internally screw threaded locking sleeve 40 from which projects a handle 41.

The locking sleeve 40 is initially loosely threaded onto the threaded portion 35, but after the clamp has been tightened using the tommy bar 34, the sleeve 40 can be tightened up against the block 36, in the manner of a lock nut, by rotating the sleeve 40 using the handle 41. This reduces the risk that the adjusting bar 33 will work loose while the clamp is in use.

A grease nipple 42 is also provided, on the block 36, to reduce the likelihood of corrosion of the adjusting rod 33.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims (14)

1. A clamp for attachment to an elongate member such as an I-section beam, the clamp comprising a pair of jaws relatively moveable towards one another to embrace the elongate member and clamp the elongate member between the jaws with a given pressure, the jaws being such that if a force is applied to the clamp tending to move the jaws in any direction, the said given pressure increases.

2. A clamp as claimed in Claim 1, in which the jaws are arranged to grip the central web of an I-section beam, rather than grip the flanges of the beam.

3. A clamp as claimed in Claim 1 or Claim 2, in which one of the jaws comprises a cam member mounted for universal pivotal movement, movement of the jaw with respect to the elongate member causing the cam member to rotate in the direction which reduces the distance between the jaws.

4. A clamp as claimed in Claim 3, in which the cam member is provided with a plurality of concentric gripping ribs.

5. A clamp as claimed in Claim 3 or Claim 4, in which the other jaw is provided with a plurality of concentric gripping ribs.

6. A clamp as claimed in any one of the preceding claims, in which the jaws are mounted on a body member which can be rapidly locked into position around the beam, to support the clamp in an overhead position while final tightening of the jaws takes place.

7. A clamp as claimed in Claim 6, in which the jaws are mounted on limbs which can be pivoted to a position in which they embrace the beam and can then be locked in that position.

8. A clamp as claimed in Claim 7, in which the limbs can be locked in position by means of a spring loaded locking pin.

9. A clamp as claimed in any one of Claims 6 to 8, in which final tightening of the jaws can be carried out by means of a threaded rod.

10. A clamp as claimed in Claim 9, in which the threaded rod is rotatable by means of a tommy bar.

11. A clamp as claimed in any one of Claims 1 to 10, having a body member shaped to have an anchorage point which lies closely adjacent to the beam when the clamp is in its operating position, thus reducing the leverage that can be applied by a load.

12. A clamp as claimed in Claim 2, or any one of Claims 3 to 11, when dependent directly or indirectly on Claim 2, in which the universal pivotal movement is brought about by means of a part spherical portion engaging within the part spherical seat of a collet, the collet being split to facilitate assembly.

13. A clamp as claimed in any one of the preceding Claims, in which a compression spring is arranged to urge one jaw towards the other.

14. A clamp constructed and arranged substantially as herein described, with reference to the accompanying drawings.