GB2522631A

GB2522631A - A clamping device

Info

Publication number: GB2522631A
Application number: GB1401544.0A
Authority: GB
Inventors: Daniel Roy Shepherd
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-01-30
Filing date: 2014-01-30
Publication date: 2015-08-05
Also published as: GB201401544D0; WO2015114301A1

Abstract

The clamping device 1 includes a first clamping face 2 at least partly formed from a ferrous or ferromagnetic material and a second clamping face 3. An adjustment means 5, 6, 7 is arranged in use to connect between the first and second clamping faces and configured to be user-operable so that the faces can be positioned in opposition to one another and so as to alter the distance between the opposed faces 2, 3. At least one magnet 4 is associated with the first clamping face to provide a magnetic flux through the first clamping face so that a ferrous or ferromagnetic work piece can be magnetically attached to the first clamping face 2. A user-operable switch (15a, Figure 5) may be mounted on a clamping head to move the magnet/s between first and second positions. The clamping head may also include a container of non-ferrous material to at least partly contain the magnet.

Description

A clamping device

Field of the Invention

The present invention relates to a clamping device for temporarily holding or securing objects tightly together to prevent movement or separation, through the application of inward pressure. More particularly, the present invention relates to a clamping device for temporarily holding or securing objects tightly together where at least part of the clamping device is arranged for holding a ferrous object in position while the clamping device is activated.

Background

A common requirement in construction tasks is to temporarily hold items together and in a specific relative orientation while they are joined in a more permanent manner. Common methods of joining are gluing, using fasteners that interconnect between the two or more items, or welding. Clamps are frequently used for this purpose, the items to be joined held between the jaws of the clamp while a joining process is carried out -e.g. while glue dries, while fasteners such as screws or bolts are inserted through the items, or while a welding operation is carried out. It can be difficult to hold items in the correct position and activate the holding device at the same time, especially for a single operator or a person working alone. For example, if using a clamp to hold two items together, the jaws need to be moved together from an open position when the items are positioned between them in the correct relative position, to a closed position where the jaws have moved towards each other enough to tighten onto the objects and create enough pressure and friction that the items will not move while the fastening process is carried out.

Prior Art

Accordingly a number of patent applications have been filed in an attempt to resolve the problem or similar, including the following: GB2471866 describes and shows a magnetic clasp having two independent sides, each side housing a permanent magnet, one side providing a protrusion within which a magnet is recessed and the other side providing a recess from which a magnet protrudes. The magnets and the housing recesses and protrusions inter-engage to attach the clasp sides together. One side may include an adjustment mechanism to vary the length of an attached strap or chain.

EP1402996 describes and shows a clamping element for a vice and/or worktable which comprises a laminar metal body and which presents, on at least one face, at least one permanent magnet designed to be fixed to the body of the vice or worktable in order to make the fixing and clamping of a piece to be machined easier.

DE10110496 describes and shows a screw clamp having a fixed metal clamp jaw and a relatively moveable metal clamp plate, both on a clamp rail. A protective liner is detachably fastened via an imbedded permanent magnet to the clamp surface of the clamp jaw and to the clamp plate. The liner is of plastic, and is plate-shaped, and its outer dimensions are larger than those of the clamp surface, to increase pressure distribution on a clamped work piece.

Sum mary of the Invention According to the present invention there is provided a clamping device comprising: a first clamping face at least partly formed from a ferrous or ferromagnetic material; a second clamping face; an adjustment means arranged in use to connect between the first and second clamping faces and configured to be user-operable so that the faces can be positioned in opposition to one another and so as to alter the distance between the opposed faces; and at least one magnet associated with the first clamping face to provide a magnetic flux through the first clamping face so that a ferrous or ferromagnetic workpiece can be magnetically attached to the first clamping face.

The provision of the magnetic flux allows a user to magnetically attach a work piece to the first clamping face in the required position and orientation, with both their hands then free to position a second workpiece between the first and second clamping faces and to alter the distance between the clamping faces to clamp the first and second workpieces together so as to be able to perform a fastening process.

In an embodiment, the clamping device further comprises a first clamping head behind the clamping face, the first clamping head configured to concentrate magnetic field lines from the at least one magnet towards the first clamping face. This helps to ensure that the flux from the magnet is used as effectively as possible to make the magnetic attachment as strong and secure as possible for a given size and strength of magnet.

In an embodiment, the clamping device further comprises a first clamping head behind the clamping face, the first clamping head having a recess configured to hold the at least one magnet. This configuration ensures that the construction is sturdy and robust, and will be less prone to damage.

In an embodiment, the clamping device further comprises an aluminium casing configured to surround the magnets within the recess except for an opening oriented towards the first clamping face. By surrounding the magnet or magnets with a casing, the field lines are diverted away from the clamp body, and can be concentrated in the clamping head.

In an embodiment, the first clamping face is removably connected to the first clamping head. This allows easy maintenance and changing of the head for different applications.

In an embodiment, the recess opens towards the first clamping face. This allows the recess to be opened towards the clamping face for maximum field strength, and also for the recess to be opened for maintenance and to change or alter the magnets.

In an embodiment, the clamping device further comprises a means for altering the position of the at least one magnet within the recess between a first position where the magnetic field passes through the ferric metal block to the clamping face, and a second position where the strength of the magnetic field passing through the clamping face is substantially reduced. This helps to ensure that workpieces can be moved or removed or repositioned easily, and also that the clamping device will not inadvertently stick to any other unrelated metallic objects.

In an embodiment, the first clamping head and magnet are configured so that in the second position, the at least one magnet is out of contact with the clamping face.

This helps to substantially reduce the strength of the magnetic flux through the clamping face.

In an embodiment, the clamping device further comprises at least one ferric metal block positioned so that when the at least one magnet is in the first position, the magnetic field passes through the ferric metal block to the clamping face, and when in the second position, the magnetic field is contained and at least partly prevented from passing through the clamping face. The ferric metal block helps to direct the magnetic filed, and containing the magnet helps to substantially reduce the strength of the magnetic flux through the clamping face.

In an embodiment, the clamping device further comprises a container of non-ferrous material within the first clamping head, the magnet at least partly contained in the container when in the second position. Containing the magnet helps to substantially reduce the strength of the magnetic flux through the clamping face.

In an embodiment, the clamping device further comprises a switch mounted on the first clamping head and user-operable to move the at least one magnet within the recess between the first and second positions. This allows a user to easily alter the position of the magnet.

In an embodiment, the first clamping head is detachably connected to the adjustment means. This assists with maintenance and also positioning of the clamping head and In an embodiment, the first clamping face is a ferrous metal. The first clamping head may further have a rubber clamping face. The first clamping head may be connectable to the adjustment means in a first orientation where the first clamping face and the second clamping face are positionable in opposition to one another and the distance between the opposed faces can be altered. The first clamping head may be connectable to the adjustment means in a second orientation where the first clamping face, for example the rubber clamping face, and the second clamping face are positionable in opposition to one another and the distance between the opposed faces can be altered. This allows the clamp to be used for gripping other materials other than just ferrous metals, and the rubberised face can be used where a softer clamping action is required, for example if the workpiece surface might scratch or deform easily.

In an embodiment, the second clamping face is formed as part of a second clamping head. The second clamping face and head may be formed from a non-ferrous material. This configuration allows simplicity of construction and avoids inadvertent magnetic clamping.

In an embodiment, the second clamping face and head are formed from aluminium.

Aluminium is inexpensive, easily worked and readily available.

In an embodiment, the adjustment means comprises a body running between the first and second clamping faces and a threaded rod. The body may have a threaded aperture to receive the threaded rod. The aperture and rod may be configured so that rotation of the rod in the aperture alters the distance between the opposed faces.

This arrangement allows simplicity of construction with sensitive adjustability and allows considerable clamping force to be exerted.

In an embodiment, the threaded rod has an aperture passing through the rod substantially perpendicularly to the axis of the rod. The clamping device may further comprise an elongate pin that is arranged in use to pass through the handle. A rubber sleeve may be located between the aperture and the pin to prevent free movement of the pin through the aperture. This arrangement allows the pin to be used as a lever for exerting rotational tightening or loosening force.

With fixed magnetic parts, the clamp could be awkward to use as tending to stick to any ferrous object. When the user tries to remove the clamp from a metal surface after use it will again be very difficult to remove. To counteract this problem in some embodiments movable magnet solutions may be envisaged.

In some embodiments magnets are held inside a sealed module that can be un-clipped and can be installed in two ways with one side magnetic and the other side a grippy rubber. This allows the clamp to grip to any surface, not just metal.

In other embodiments a switch is rotated to an on position, and an internal magnet is aligned with two ferric metal blocks that multiply the magnets power. When in an off position the magnet is reorientated to sit in a nonferrous metal which contains the field stopping it from magnetising the clamp. Such a method is commonly used on magnetic stands.

In other embodiments when a paddle is in the up position, the magnet is moved away from the steel base plate and by disconnecting the magnet from the steel plate, the strength of the magnetic field is greatly reduced making it easy to remove the clamp.

In an embodiment, the adjustment means further comprises a sliding arm. This adds to the adjustability of the clamping device.

Brief Description of Figures

Figure 1 shows a perspective view from above looking down of a clamping device according to an embodiment of the invention, the clamping device having first and second clamping heads oriented so that clamping faces on the heads are opposed, an arm connecting between the clamping heads, the distance between the face adjustable via the arm and also via a threaded rod that passes through the second clamping head.

Figure 2 shows a side view of the clamping device of figure 1 Figure 3 shows an exploded perspective view of the clamping device of figures 1 and 2.

Figure 4 shows a close up cutaway detail view of the first clamping head of the clamping device of figures 1 to 3, showing a recess, a casing that slots into the recess and magnets that sit within the casing, the recess and slot open towards the lower or front end or side adjacent to the clamping face in use.

Figure 5 shows a variation or alternative to the first clamping as shown in figures 1 to 4, the clamping head having a user operable switch to adjust the position of the magnets inside the head.

Figure 6 shows a variation or alternative to the clamping head with user operable switch as shown in figure 5.

Figure 7 shows another variation, the head in this variation having two faces, one rubberised, the head detachable for orientation of either face as required and for storage.

Detailed Description of Figures

An embodiment of clamping device 1 according to the invention is shown in figures 1 to 4. The clamping device 1 has a sliding arm 7 formed from an elongate member, and having a plurality of notches 8 along the inner edge a first clamping face 2. The arm forms part or the whole of a body between a first clamping head 9 connected to the arm 7 at one end, and a second clamping head 10 movably connected to the arm. The second clamping head 10 is movable along the length of the arm from the other end to the first clamping head 9 by way of the notches, which allow the second clamping head 10 to be moved between a plurality of discrete positions along the length of the arm 7. Each of the clamping heads has an associated clamping face -first clamping face 2 and second clamping face 3. These are connected to the clamping heads 9, 10 in such a manner that they are opposed or facing towards one another, and so that they can be brought into contact and moved apart This can be done in two ways: by movement of the second clamping head 10 along the arm 7, and by independent movement of the second clamping face 3 as will be described in detail below. Clamping face 2 is at least partly formed from a ferrous material. At least one magnet 4 is mounted in the first clamping head 9 to provide a magnetic flux through the first clamping face 2, so that a ferrous workpiece can be magnetically attached to the first clamping face 2. The provision of the magnetic flux allows a user to magnetically attach a work piece to the first clamping face 2 in the required position and orientation. Both their hands are then free to position a second workpiece between the first and second clamping faces 2, 3 and to then alter the distance between the clamping faces 2, 3 to clamp the first and second workpieces together so as to be able to perform a fastening process.

As shown in figure 4, the first clamping head 9 has a recess 11 behind the clamping face 2, which is configured to hold at least one magnet 4. The recess opens forwards, or towards the first clamping face. An aluminium casing 12 is configured to sit snugly in the recess to surround the magnets and prevent contact with the first clamping head 9, except for an opening oriented towards the first clamping face 2.

By surrounding the magnet or magnets with a casing, the field lines are diveited away from the clamp body, and can be concentrated through the clamping face 2.

The first clamping face 2 is removably connected to the first clamping head 9 so that the magnets can be changed or their overall numbers changed to change the magnetic strength.

The second clamping face 3 is formed as an integral part of the second clamping head 10, of a non-ferrous material, such as aluminium. An extension 13 connects the second clamping face 3 to the arm 7, the extension 13 and second clamping face 3 moving along the arm 7. Where the word body' is used in this specification, the arm 7 and extension 13 can be considered together to be the body, or the arm 7 can be considered by itself, as appropriate from the context.

Neodynium magnets may be inside an aluminium housing in order that the magnetic field is concentrated thereby. By surrounding the magnets in an aluminium casing and allowing an iron clamping head to touch the magnets, field lines are concentrated and diverted away. Clamping heads have a central cut out to enable clamping of circular objects..

The extension 13 has a threaded aperture running through it, aligned pointing towards the first clamping face 2. A threaded rod 5 passes through the threaded aperture so that the threads co-operatively interlock. Rotation of the rod 5 in the aperture alters the distance between the opposed first and second clamping faces 2, 3. An elongate pin 6 passes through the rod 5 to act as a handle, and a rubber sleeve 14 passes around the pin 6 where it passes through the rod 5 to prevent free movement of the pin 6 through the aperture. That is, the pin 6 can be pushed through the rod 5, but force must be applied, and it will not slide under gravity if the clamping device 1 is tilted away from the horizontal.

The provision of the magnetic flux through the clamping face 2 allows a user to magnetically attach a work piece to the first clamping face 2 in the required position and orientation, with both their hands then free to position a second workpiece between the first and second clamping faces 2, 3, and then to alter the distance between the clamping faces 2, 3 to clamp the first and second workpieces together so as to be able to perform a fastening process.

In variations, as shown in figures 5 and 6, the position of the magnet 4 within the recess can be altered. In this variation, a ferric block is mounted in the head 9, or the head itself is formed as a ferric block. In a first position within the head 9, the magnet 4 is positioned so that the magnetic field passes through the ferric metal block to the first clamping face 2. In a second position, the magnet is located in an orientation and/or position where the strength of the magnetic field passing through the clamping face 2 is substantially reduced. A user switches the magnet between the relevant positions using a switch 15 on the head 9 (switch isa in figure Sand 15b in figure 6).

This helps to ensure that workpieces can be moved or removed or repositioned easily, and also that the clamping device will not inadvertently stick to any other unrelated metallic objects.

In the variation shown in figure 6, the first clamping head 9 and magnet are configured so that in the second position, the magnet is moved in and out of contact with the inside surface of the clamping face 3. When out of contact, this helps to substantially reduce the strength of the magnetic flux through the clamping face.

In the variation shown in figure 5, the clamping device further comprises at least one ferric metal block positioned so that when the at least one magnet is in the first position, the magnetic field passes through the ferric metal block to the clamping face, and when in the second position, the magnetic field is contained and at least partly prevented from passing through the clamping face. The ferric metal block helps to direct the magnetic filed, and containing the magnet helps to substantially reduce the strength of the magnetic flux through the clamping face. In this variation, a container of non-ferrous material can also be mounted within the first clamping head, the magnet at least partly contained in the container when in the second position. Containing the magnet helps to substantially reduce the strength of the magnetic flux through the clamping face. The container can be similar to that described above with reference to figure 4.

In a further variation, as shown in figure 7, the first clamping head 9 can be detachable from the remainder of the clamping device 1, and connectable in two orientations to present two different clamping faces to a workpiece. The first clamping face is a ferrous metal similar to that previously described. The first clamping head further has a rubber clamping face 16. The first clamping head 9 is connectable in a first orientation where the rubber clamping face opposes the second clamping face 3, or where the ferrous clamping face opposes the second clamping face 3. This allows the clamp to be used for gripping other materials other than just ferrous metals, and the rubberised face can be used where a softer clamping action is required, for example if the workpiece surface might scratch or deform easily.

The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing from the scope of invention. Firstly it will be understood that any features described in relation to any particular embodiment may be featured in combinations with other embodiments.

With respect to the specification therefore, it is to be realised that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of the principles of the invention, with variation and implementation obvious and clear on the basis of either common general knowledge or of expert knowledge in the field concerned. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as set out in the accompanying claims.

Claims

Claims 1. A clamping device, comprising: a first clamping face at least partly formed from a ferrous or ferromagnetic material; a second clamping face; an adjustment means arranged in use to connect between the first and second clamping faces and configured to be user-operable so that the faces can be positioned in opposition to one another and so as to alter the distance between the opposed faces; and at least one magnet associated with the first clamping face to provide a magnetic flux through the first clamping face so that a ferrous or ferromagnetic workpiece can be magnetically attached to the first clamping face.
2. A clamping device as claimed in claim 1, further comprising a first clamping head located behind the first clamping face, the first clamping head configured to concentrate magnetic field lines from the at least one magnet towards the first clamping face.
3. A clamping device as claimed in either of claims 1 and 2, further comprising a first clamping head located behind the clamping face, the first clamping head having at least one recess configured to hold the at least one magnet.
4. A clamping device as claimed in claim 3, further comprising an aluminium casing configured to surround the at least one magnet within the at least one recess except for an opening oriented towards the first clamping face.
5. A clamping device as claimed in claim 4 wherein the first clamping face is removably connected to the first clamping head.
6. A clamping device as claimed in claim 5 wherein the at least one recess opens towards the first clamping face.
7. A clamping device as claimed in claim 3 wherein the first clamping head further comprises a means for altering the position of the at least one magnet within the recess between a first position where the magnetic field passes through the ferric metal block to the clamping face, and a second position where the strength of the magnetic field passing through the clamping face is substantially reduced.
8. A clamping device as claimed in claim 7 wherein the first clamping head and magnet are configured so that in the second position the at least one magnet is out of contact with the clamping face.
9. A clamping device as claimed in claim 7 wherein the first clamping head further comprises at least one ferric metal block positioned so that when the at least one magnet is in the first position, the magnetic field passes through the ferric metal block to the clamping face, and when in the second position, the magnetic field is contained and at least partly prevented from passing through the clamping face.
10. A clamping device as claimed in claim 8 further comprising a container of non-ferrous material within the first clamping head, the magnet at least partly contained in the container when in the second position.
11. A clamping device as claimed in any one of claims 7 to 10 further comprising a switch mounted on the first clamping head and user-operable to move the at least one magnet within the recess between the first and second positions.
12. A clamping device as claimed in claim 3 wherein the first clamping head is detachably connected to the adjustment means.
13. A clamping device as claimed in claim 12 wherein the first clamping face is a ferrous metal, the first clamping head further having a rubber clamping face, the first clamping head connectable to the adjustment means in a first orientation where the first clamping face and the second clamping face are positionable in opposition to one another and the distance between the opposed faces can be altered, and a second orientation where the rubber clamping face and the second clamping face are positionable in opposition to one another and the distance between the opposed faces can be altered.
14. A clamping device as claimed in any one of claims 1 to 13 wherein the second clamping face is formed as part of a second clamping head, the second clamping face and head formed from a non-ferrous material.
15. A clamping device as claimed in claim 14 wherein the second clamping face and head are formed from aluminium.
16. A clamping device as claimed in any one of claims 1 to 14 wherein the adjustment means comprises a body running between the first and second clamping faces and a threaded rod, the body having a threaded aperture to receive the threaded rod, the aperture and rod configured so that rotation of the rod in the aperture alters the distance between the opposed faces.
17. A clamping device as claimed in claim 14 wherein the threaded rod has an aperture passing through the rod substantially perpendicularly to the axis of the rod, the clamping device further comprising an elongate pin that passes through the handle, and a rubber sleeve that locates between the aperture and the pin to prevent free movement of the pin through the aperture.
18. A clamping device as claimed in any one of claims 1 to 14 wherein the adjustment means further comprises a sliding arm.
19. A clamping device substantially as herein described with reference to the figures.