WO2009003482A1

WO2009003482A1 - Manually operable, lokableclamp, for operation with one hand

Info

Publication number: WO2009003482A1
Application number: PCT/DK2008/000251
Authority: WO
Inventors: Bo Christensen
Original assignee: Bo Christensen
Priority date: 2007-07-04
Filing date: 2008-07-03
Publication date: 2009-01-08

Abstract

The invention provides a clamp (1) with two arms (2, 3) and a spring (12) which is arranged to bias one end (6, 7) of the arms towards each other when a hand grip in an opposite end of the arms is released. The clamp comprises a retaining structure (13, 14) being interchangeable between a released configuration in which the arms are free to move away from each other against the spring force and a locked configuration in which the arms are prevented from moving away from each other. The clamp comprises, means (21, 24) for changing the retaining structure to the locked configuration when the hand grip is released. The clamp has a tightening structure (15) by which a pressure between the arms can be- increased. The clamp provides an easy, one hand operated clamp which may provide a good gripping force.

Description

MANUALLY OPERABLE, LOKABLECLAMP, FOR OPERATION

WITH ONE HAN

INTRODUCTION

The present invention relates to a clamp comprising a first arm and a second arm each comprising a handle end facilitating a handgrip and a jaw end. The first and second arms are movably linked intermediate the jaw and handle ends of the arms to enable movement of the arms relative to each other in a closing direction and in an opposite opening direction, where two opposite engagement surfaces are moved towards each other when the arms are moved in the closing direction and the engagement surfaces are moved away from each other when the arms are moved in the opening direction. The clamp further comprises a spring structure arranged to bias the arms in the closing direction. In particular, the invention relates to a clamp which is easily operated by hand.

BACKGROUND OF THE INVENTION

Numerous hand operated clamps are developed for various purposes. A typical clothes-peg comprises two arms and a spring which is arranged to bias one end of the arms towards each other when a handgrip in an opposite end of the arms is released. Various gripping tools exist e.g. designed for cabinet making, smith's working, or simply for assembling items or as a means for suspending items such as lamps, screens, ventilators etc. Typically the clamps referred to are adapted for temporary fastening, joining or suspension. In order to make hand operation easy, the spring typically applies a limited force, and the gripping force is therefore normally limited. DESCRIPTION OF THE INVENTION

It is an object of a preferred embodiment of the invention to improve the clamps, to enable a more firm gripping, and to provide a clamp which is more easily operated with one hand. Accordingly, the invention provides a clamp comprising a retaining structure being interchangeable between a released configuration in which the arms are free to move in the opening direction and a locked configuration in which the arms are prevented from moving in the opening direction, the clamp further comprising at least one tightening structure movable in a shortening direction to shorten a distance between the engagement surfaces when the retaining structure is in the locked configuration, the clamp further comprising means for changing the retaining structure to the locked configuration when the handle ends are released.

Due to the combination of the retaining structure and the tightening structure, the clamp may, in a first operational step be attached to an object in a manner corresponding to the operation of a traditional clothes- peg. The handle ends of the arms are moved towards each other whereby a gap is formed between the engagement surfaces. The surfaces are arranged on opposite sides of an object which is to be clamped, and the handgrip in the handle ends is released whereby a spring force urges the engagement surfaces towards opposite sides of the object ands whereby the retaining structure is changed to the locked configuration. This operation may easily be performed by use of only one hand. Meanwhile, the user may use the other hand to firmly hold the object or objects to which the clamp is attached. The spring structure will typically provide sufficient spring force to hold the clamp's own weight by the friction between the engagement surfaces and the object in question. In a second operational step, the hand which was used for the handgrip in the handle ends is now released and can be used for operating the tightening structure and thereby for providing a more firm grip. The retaining structure - now in the locked configuration - will prevent the arms from moving in the opening direction. Accordingly, the invention provides a clamp which may clamp strongly around an object and yet easily be operated by use of only one hand.

Each one of the first arm and the second arm could be made from a single rigid element, or they could be assembled from several individual elements. As an example, the handle end could be made from one element and the jaw end could be made from another element. In one embodiment, the jaw end, and a part of the retaining structure is formed by one element of one of the arms while the handle end and another part of the retaining structure is formed by another element of the same arm.

By handle end is meant a portion of each arm extending from the point at which the arms are linked towards one free end of the arm, and by jaw end is meant a portion of each arm extending from the point at which the arms are linked towards an opposite free end of the arm. By engagement surface is meant a surface which engages an object when the clamp is arranged to clamp that object. The engagement surfaces are moved towards and away from each other by the jaw ends of the arms. The engagement surface may e.g. be a surface portion of one of the jaw ends, or it may be a surface portion of a separate jaw which is attached to the jaw end.

The handle end may be made from an element having a shape, or comprising a material which facilitates a handgrip, e.g. with a cross-section which is relatively large compared to other elements, or e.g. with a soft outer surface having a surface friction which is larger than the surface friction of other elements. The jaw end may be made from an element having a surface which is hard relative to the surface of other elements, and in particular, the engagement surface may have a surface which is hard compared to the surface of other areas of the clamp.

The spring structure may comprise a wire or blade spring which is arranged to bias the arms in the closing direction in which direction collision between the engagement surfaces may stop the movement. The spring structure may alternatively comprise a helical spring or another flexibly deformable means which is arranged to bias the arms in the closing direction.

To facilitate an unsupported suspending of a clamp on an object, the spring structure may have sufficient spring effect or strength to provide a pressure of the engagement surfaces towards each other to support the weight of the clamp even when the engagement surfaces engage a smooth or even slippery surface. For this purpose, the engagement surface may comprise a surface layer which increases the surface friction compared to the surface friction of other parts of the clamp. Additionally, or alternatively, the spring may provide a force of the surfaces towards each other, which force is in the range of at least 2-5 Newton such as in the range of 3-10 Newton.

The retaining structure may prevent any movement of the engagement surfaces in a direction away from each other, except if such a movement is occasioned by movement of the handle ends. For this purpose, at least one of the arms may comprise at least two separate elements which are movable relative to each other. Movement of the two separate elements relative to each other may change the retaining structure between the locked and the released configurations. Alternatively, the retaining structure is manually movable by use of a separate control element. In this case, the retaining structure may also be used for locking the clamp in a closed position in which the engagement surfaces abut each other, e.g. for safe storage purpose. In this embodiment, the retaining structure may be biased towards the locked position by a spring force, and the retaining structure is then moved to the released position by the control element.

The tightening structure may comprise a leverage or a gearing structure which facilitates that the movement in the shortening direction can cause a relatively large compressing force on an object which is located between the engagement surfaces by use of a force which is small relative to the compressing force, i.e. a structure which converts a movement triggered by a low force over a longer distance to movement capable of exerting a large force over a short distance.

In one embodiment, the tightening structure comprises an actuator which is arranged between one of the engagement surfaces and a corresponding jaw end of one of the arms. The engagement surface may e.g. form part of a jaw element which is hinged or otherwise movably attached to one of the arms, and the actuator may be arranged between the jaw and the jaw end of that arm or between the jaw and the jaw end of the other arm. The actuator may e.g. comprise a spindle which is received in a cooperating internally threaded structure of the jaw end in question. The tightening structure may comprise a quick-release feature by which the jaw element and thereby the engagement surface which is influenced by the tightening structure is released quickly. If the tightening structure comprises a spindle, the spindle may be received in an opening in which an internal threading can be moved between a position where the external threading of the spindle is engaged and a position in which it is not engaged by the internal threading. To provide movement of the engagement surfaces in a direction away from each other when the jaw ends move away from each other, the jaw element may be connected to one of the jaws. In one embodiment, the spindle extends through the jaw portion in which it is received and the jaw element is attached to a free end thereof. In another embodiment, the jaw element and the jaw end is connected by use of a spring element, e.g. a blade spring, a helical spring, a rubber band, or a wire spring. The spring may be arranged between the jaw element and any one of the jaw ends. The jaw element and the jaw end could also, by use of magnetic force, be releasably connected to each other. In a third embodiment, the tightening structure and the jaw may be connected in a sliding relationship to each other.

The movable link may comprise a pivotal connection facilitating rotational movement of the arms relative to each other. In particular, the arms may be arranged so that the movement is in the closing direction when the handle ends are moved in a direction away from each other, vice versa.

DETAILED DESCRIPTION

A preferred embodiment of the invention will now be described in further details with reference to the drawing in which:

Fig. 1 illustrates a perspective view of a clamp according to the invention,

Fig. 2 illustrates an exploded view of a clamp according to the invention,

Figs. 3-4 illustrate enlarged views of the retaining structure, and

Fig. 5 illustrates an enlarged perspective view of the retaining structure.

As illustrated in Figs. 1 and 2, a clamp 1 according to the invention comprises a first arm 2 and a second arm 3. Each arm comprises a handle end 4, 5 by which a user may operate the clamp. Opposite the handle ends 4, 5, the arms form jaw ends 6, 7. Each jaw either forms a corresponding engagement surface 8 or it is arranged to move an engagement surface 9. One of the engagement surfaces 8 forms part of the first arm 2 and the other engagement surface 9 forms part of a jaw 10 which is arranged to be moved by the jaw end 6 of the second arm 3 towards the other engagement surface 8. The jaw 10 is rotationally joined to the remaining part of the clamp by use of the axle 11.

The axle 11 also forms a pivotal connection between the arms 2, 3 and thereby facilitates rotational movement of the arms 2, 3 relative to each other around the axle 11 so that the engagement surfaces 8, 9 are moved towards each other when the handle ends 4, 5 are moved away from each other, vice versa.

The clamp 1 further comprises a spring structure comprising a wire spring 12 and a retaining structure comprising a rack 13 and a ratchet 14. Alternatively, e.g. a friction lock could be used.

The clamp 1 further comprises at least one tightening structure 15 movable in a shortening direction, indicated by the arrow A, to shorten a distance between the engagement surfaces 8, 9 when the retaining structure 13, 14 is in the locked configuration. The tightening structure 15 comprises a spindle 16 which rotates in an internally threaded hole through the jaw end 6 of the second arm 3

The retaining structure is more clearly seen in Figs. 2-5. The teeth 17 and ratchet 14 are provided with an angle so that the ratchet 14 easily jumps between the teeth 17 when the handgrip is released and the arms 2, 3 are moved in the closing direction. During an attempt to move the arms 2, 3 in the opposite opening direction, the teeth 17 are engaged by the ratchet 14 which thereby prevents the movement. Instead of the teeth 17 and ratchet 14, the retaining structure 13, 14 could comprise other kinds of retaining parts - possibly similarly shaped - e.g. with locking surfaces with a high friction, the locking surfaces engaging and locking against each other when the handgrip is released and disengaging otherwise.

The first arm 2 comprises a first arm segment and a second arm segment, in Fig. 2 indicated by numeral 18, 19. The arm segments are joined in a linkage formed by the axle 20. One of the segments 18 forms the jaw end 7 of the first arm 2, and the other one of the segments 19 forms the handle end 5 of the first arm 2.

The link between the two segments 18, 19 of the first arm 2 facilitates movement of the first arm segment 18 relative to the second arm segment 19. Since the ratchet 14 forms part of the second segment 19, i.e. the segment which forms the handle end 5, the ratchet 14 is movable relative to the rack 13 by movement of the two segments relative to each other. Provided that the engagement surfaces 8, 9 abut each other or opposite sides of an object being clamped, the movement of the handle end 5 towards the handle end 4 results in movement of the two segments of arm 2 relative to each other against the force of the auxiliary spring 21. By this movement, the ratchet 14 is moved out of the engagement with the rack 13. The movement causes the auxiliary spring 21 to be compressed until the protrusion 24 on the second segment 19 abuts the protrusion 25 on the first segment 18. Thereafter the mutual abutment of the protrusions 24, 25 will cause the segments 18, 19 to pivot together around the axle 11 , whereby the jaw ends 6, 7 are separated and the pressure on the engagement surfaces 8, 9 relieved. The ratchet 14 can easily be disengaged in the rack 13 since the rack 13 and the ratchet 14 rotate around different axles 11 , 20. The relatively large extent of the rack 13 allows the clamp 1 to grip and lock onto objects of varying size.

When the handgrip in the handle ends 4, 5 is released, the handle ends 4, 5 move away from each other and the engaging surfaces 8, 9 move towards each other under spring force from the spring 12. Simultaneously, the first segment 18 is moved relative to the second segment 19 by the auxiliary spring 21 acting on the protrusion 24 to a position in which the ratchet 14 again engages the teeth 17 of the rack 13, thereby changing the retaining structure to the locked configuration.

The wire spring 12 comprises an upper portion 22 and a lower portion 23. The upper and lower portions are both in contact with a handle end of an arm, and the wire spring 12 thus biases the handle ends 4, 5 away from each other and thereby biases the clamp 1 in the closing direction.

The clamp may comprise an attaching structure, e.g. in the form of threaded holes, threaded pins, wires, screw clamping structures, rubber bands etc. for combining the clamp with other clamps or for attaching the clamp to a rod. In one embodiment, the clamp comprises a set of two crossing guides, e.g. formed by holes or depressions for receiving crossed bars which could be attached to the clamp by a screw clamping structure. The engaging surfaces may subsequently be used for clamping an additional bar, a lamp, a curtain or other items, e.g. in stage or display constructions.

In the disclosed embodiment, the arms rotate relative to each other, and the jaw element rotates relative to the arms. In other embodiments, the arms and/or the jaw element is/are arranged so that it moves in parallel movements etc.

Claims

1. A clamp (1) comprising a first arm (2) and a second arm (3), each arm comprising a handle end (4, 5) and a jaw end (6, 7), both the handle ends (4, 5) being adapted to be forced together by a handgrip, the clamp further comprising a spring structure (12) and a retaining structure (13, 14), the arms (2, 3) being movably linked intermediate the jaw and handle ends (4, 5, 6, 7) to enable movement of the arms (2, 3) relative to each other in a closing direction and in an opposite opening direction, where two opposite engagement surfaces (8, 9) are moved towards each other when the arms (2, 3) are moved in the closing direction and the engagement surfaces (8, 9) are allowed to move away from each other when the arms (2, 3) are moved in the opening direction, the spring structure (12) being arranged to bias the arms (2, 3) in the closing direction, and the retaining structure (13, 14) being interchangeable between a released configuration in which the arms (2, 3) are free to move in the opening direction and a locked configuration in which the arms (2, 3) are prevented from moving in the opening direction, the clamp (1) further comprising at least one tightening structure (15) movable in a shortening direction to shorten a distance between the engagement surfaces (8, 9) when the retaining structure (13, 14) is in the locked configuration, the clamp (1) further comprising means (21 , 24) for changing the retaining structure (13, 14) to the locked configuration when the handgrip forcing the handle ends (4, 5) together is released.

2. A clamp according to claim 1 , wherein the movable link comprises a pivotal connection facilitating rotational movement of the arms (2, 3) or a part thereof relative to each other.

3. A clamp according to any of claims 1 or 2, wherein the movable link provides movement in the closing direction upon movement of the handle ends (4, 5) in a direction away from each other.

4. A clamp according to any of claims 1-3, wherein at least one of the engagement surfaces (9) forms part of a jaw (10) which is connected to a corresponding one of the arms (2), the clamp further comprising an actuator (15, 16) arranged between the jaw (10) and a first one of the jaw ends (6) to enable movement of the jaw (10) relative to the jaw end (7) of the corresponding arm (2) and thereby to change the distance between the engagement surfaces (8, 9).

5. A clamp according to claim 4, wherein the actuator (15, 16) comprises an externally threaded spindle (16) which is received in a cooperating internally threaded structure of the first jaw end (6).

6. A clamp according to any of claims 4-5, wherein the first jaw end (6) is not the jaw end (7) of the corresponding arm.

7. A clamp according to any of claims 4-6, wherein the jaw (10) is pivotally connected to at least one of the arms (2, 3).

8. A clamp according to claim 2 and 7, wherein the pivotal connection between the arms (2, 3) and the pivotal connection between the jaw (10) and at least one of the arms (2, 3) is provided by a single axle (11 ) extending through holes in the arms (2, 3) and/or through holes in the jaw (10).

9. A clamp according to any of the preceding claims, wherein the retaining structure (13, 14) comprises two retaining parts (13, 14), which during or after movement of the arms (2, 3) in the closing direction are mutually engageable to prevent movement in the opposite opening direction, and the retaining parts (13, 14) being movable between an engaging position forming the locked configuration, in which the retaining parts (13, 14) engage each other, and an open position forming the released configuration, in which the retaining parts (13, 14) do not engage each other.

10. A clamp according to claim 9, wherein each retaining part (13, 14) comprises a locking surface (13, 14), the locking surfaces (13, 14) having a high mutual friction.

11. A clamp according to claim 9, wherein one retaining part (13) comprises a rack (13) and the other retaining part (14) comprises a ratchet (14), the rack (13) forming a track with teeth (17), the ratchet (14) engaging the teeth (17) of the rack (13) in the engaging position, and the ratchet (14) not engaging the teeth (17) of the rack (13) in the open position.

12. A clamp according to any of claims 9 to 11 , comprising an auxiliary spring structure (21 ) arranged to bias the retaining parts (13, 14) towards the engaging position by a spring force, and wherein at least a part (19) of one of the arms (2) interacts with the retaining parts (13, 14) to move the retaining parts (13, 14) towards the open position during movement of the handle ends (4, 5) of the arms (2, 3) towards each other.

13. A clamp according to any of claims 9-12, wherein the retaining parts (13, 14) are arranged to be moved to the engaging position upon movement of the tightening structure (15) in the shortening direction.

14. A clamp according to any of the preceding claims, wherein at least one of the arms (2, 3) comprises a first arm segment (18) and a second arm segment (19), the arm segments being joined in a linkage.

15. A clamp according to claim 14, wherein the first arm segment (18) forms the jaw end (7) of that arm (2) and a second arm segment (19) forms the handle end (5) of that arm (2).

16. A clamp according to any of claims 14-15, wherein the linkage facilitates movement of the first arm segment (18) relative to the second arm segment (19), one of the segments (19) being adapted to change the retaining structure (13, 14) from the locked configuration to the released configuration upon movement of the first arm segment (18) relative to the second arm segment (19).

17. A clamp according to claim 9 and 16, wherein one of the retaining parts (14) forms part of one of the arm segments (19).