A clamp device

FIELD OF INVENION

THIS INVENTION relates to mechanical fasteners and specifically to a clamp device.

BACKGROUND OF THE INVENTION

The Inventor is aware of a clamp device in the form of a G-clamp which has many industrial applications, however may be inappropriate or too cumbersome for lighter applications. The Inventor is also aware of a clothes peg which, while suitable for some applications, may not be suitable for others. The inventor desires an improved clamp device.

SUMMARY OF INVENTION

Accordingly, the invention discloses a clamp device which includes: a housing defining a guide formation; a closure member mounted for longitudinal displacement relative to the housing; a pair of oppositely disposed clamp surfaces or jaws provided respectively on the housing and the closure member, the closure member being displaceable relative to the housing between a closed condition in which the jaws abut or are closely spaced and an open condition in which the jaws are spaced further apart; a cam surface provided on one of the housing and the closure member; and

a complementary cam follower provided on the other of the closure member and the housing, the cam follower cooperating with the cam surface to urge the closure member into at least one bias condition.

The guide formation may be in the form of a longitudinally extending guide- channel defined within the housing.

The housing may include an aperture in line with the channel out of which a portion of the closure member projects, cantilever-fashion. The closure member may then include a clamp formation at its free end which defines thereon the clamp surface. The clamp surfaces may extend generally transversely to the length of the body.

The clamp device may be dimensioned so that it can conveniently be held in one hand. The housing may include a slot extending generally parallel with the guide- channel, the closure member including a tab or lug projecting outwardly through the slot, the tab being engageable by a user to slide the closure member back and forth, in use. The housing may include a series of concave recesses at a side opposite the slot, the recesses serving to accommodate curled fingers of the user to grasp the clamp device, leaving the thumb free to operate the tab.

Part of the body of the closure member may be accommodated within the guide-channel with a sliding clearance to allow sliding displacement of the closure member relative to and within the housing. The housing may be elongate with the guide-channel extending longitudinally and linearly therein.

The cam surface and cam follower may be co-operable to urge the closure member into at least two bias conditions. The bias conditions may include, for example, an open condition and a closed or clamped condition.

In one embodiment, the cam surface may be provided on the housing and the cam follower may then be provided on the closure member. More particularly, the

cam follower may be in the form of a cantilever spring formation. In such case, the cam formation may be adjacent to the guide channel.

The closure member may include an elongate body, the spring formation in such case projecting from the body.

The cam formation may be generally convex in shape having an apex and two surfaces either side thereof, the surfaces being inclined relative to the length of the channel. It is thus to be understood that the cam formation may serve to urge the spring formation, and hence the closure member, outwardly in one of two opposite directions depending on which side of the apex, and hence which inclined surface, the spring formation engages. More particularly, if the spring formation engages the cam formation on one side of the apex, the closure member may be urged into its closed condition whereas if the spring formation engages the cam formation on the other side, the closure member may accordingly be urged into its open condition.

The shape and/or gradient of the cam formation may be configured to adjust the bias and compliance characteristics of the closure member. In an example embodiment, the surface one side of the apex is relatively steep and curved, urging the closure member more strongly into its closed condition if the spring formation engages that surface. On the other hand, the surface the other side of the apex may have a relatively gentle gradient, urging the closure member more gently into its open condition.

The closure member may be of unitary construction and may be of a synthetic polymeric material. The housing may be formed of two similar or identical interconnecting halves and may also be of a synthetic polymeric material. For example, the closure member and housing may be of acetal copolymer. In assembly, the closure member may be placed between the two open halves of the housing, the two halves then being interconnected and secured to each other (e.g. by an adhesive, high frequency welding, or the like) so that the closure member is held captive within the housing.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be further described, by way of example, with reference to the accompanying diagrammatic drawings.

In the drawings:

Figure 1 shows a three-dimensional view of a clamp device, in accordance with the invention, in its closed or clamped condition;

Figures 2 and 3 show side elevational views of the clamp device of Figure 1 respectively in its closed and open conditions;

Figures 4 to 6 show cross-sectional side elevational views of the clamp device of Figure 1 in closed, intermediate and open conditions respectively; Figure 7 shows an exploded three-dimensional view of the clamp device of Figure

1; and

Figure 8 shows a side view of a closure member of another clamp device in accordance with the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Referring to all the Figures, reference numeral 10 generally indicates a clamp device in accordance with the invention. The clamp device 10 includes a housing 12 and a closure member 14. The closure member 14 includes a generally elongate body

16 and a cam follower in the form of a cantilever spring formation 18 projecting from the body 16 intermediate its ends. The spring formation 18 is generally arcuate.

The housing 12 defines therein a linearly and longitudinally extending guide formation in the form of a guide-channel 20 in which the body 16 of the closure member 14 is accommodated with a sliding clearance. The closure member 14 is thus longitudinally displaceable relative to and within the housing 12.

The housing 12 further defines a cam formation (or cam surface) 22 adjacent the guide-channel 20. The cam formation 22 is in register with a free end of the spring formation 18.

The housing 12 defines at one end an aperture 30 through which a portion of the closure member 14 projects, cantilever fashion. The clamp device 10 includes a pair of opposed facing clamp surfaces or jaws 24 for engaging and clamping a work piece therebetween. The clamp surfaces 24 are serrated to enhance grip of a work piece when clamped. One of the clamp surfaces 24 is defined a surface at the end of the housing 12 defining the aperture 30, while the other clamp surface 24 is defined by a clamp formation 32 projecting transversely from a free end of the closure member 14. As illustrated in Figure 8 of the drawings, which shows a closure member 14 of another clamp device, the specific configuration of the clamp formation 32 can vary.

The clamp device 10 is dimensioned so that it can conveniently be held or grasped in one hand. The clamp device 10 in its closed condition for example has a length of 10 cm. The housing 12 defines at an upper side thereof a slot 26 extending generally parallel with the guide-channel 20. The closure member 14 includes a corresponding tab 28 which projects through the slot 26 and which is engageable by a user to slide the closure member 14 back and forth. The other side of the housing 12 includes a series of concave recesses 34 for accommodating curled fingers of the user. When grasped, the users thumb is free to displace the tab 28.

The cam formation 22 is generally convex in shape and includes an apex 40 with two surfaces 42, 44 on either side thereof. The surface 42 proximate the aperture 30 extends linearly and has a relatively gentle incline. In this example, the surface 42 is inclined by an angle of approximately 19° relative to the length of the housing 12. The surface 44 remote from the aperture 30 is convex and is generally steeper than the linear surface 42. In this example, the concave surface 44 has a radius of curvature of approximately 16 mm. The gradients and angles at which the surfaces 42, 44 are

inclined influence the compliance of the closure member 14 when sliding back and forth and influence the clamping force of the clamp device 10.

A closed bias condition is thus created when the spring formation 18 engages the curved surface 44 as far back as possible (see Figure 4). A free end of the spring formation 18 is visible through an opening in the bottom of the housing 12. In an intermediate position, the free end of the spring formation 18 engages the apex 40 (see Figure 5) and, on the other hand, an open bias position is created when the spring formation engages the linear surface 42 as far forward as possible (see Figure 6).

The invention will now be further described in use. The user wishes to clamp something, for example a bag or packet containing a foodstuff, with the clamp device 10. The user grasps the clamp device 10 by curling his/her fingers around the housing 12 and letting them rest in the recesses 34. A front of the clamp device 10 (the end having the clamp formation 32) projects forwardly out of the user's hand and his/her thumb finds itself adjacent to the tab 28.

The user then displaces the tab 28 forwardly in the direction indicated by arrow 50. As the spring formation 18 runs up the convex surface 44 of the cam formation 22, the spring formation 18 is displaced towards the body 16 against its bias. As the convex surface 44 is relatively steep, it provides the closure member 14 with a relatively low compliance in the direction of arrow 50. Once the free end of the spring formation 18 passes over the apex 40, the linear surface 42 gently urges the closure member 14 into its fully open condition.

The user then places the work piece, e.g. a plastic bag, between the clamping formations 24 and displaces the tab 28 backwards in the direction indicated by arrow 52. The spring formation 18 is displaced relatively easily (i.e. high compliance) over the linear surface 42 and as its free end passes over the apex 40, the concave surface 44 urges the closure member 14 into its closed position and continues to maintain a grip on the work piece.

The Inventor envisages that the clamp device 10 could be used for any number of applications and for domestic applications in particular. It may be particularly useful for ceiling plastic bags which are being opened, e.g. cereal bags, packets of chips, and the like. It could also be used to replace a conventional clothes peg.

The invention as exemplified is advantageous as it provides a cost-effective and easy to manufacture clamp device 10 which is convenient and effective to use.