A quick action bar clamp of the type under consideration is disclosed in United States Patents Serial Nos. 4,926, 722, 5,009, 134 and 5,022, 137, which bar clamp generally comprises a slide bar, a fixed jaw member located at one end portion of the slide bar, a movable jaw arranged facing the fixed jaw and to be moved along the slide bar towards the fixed jaw to clamp a work-piece or work-pieces there-between in order to facilitate an appropriate operation thereon.

In a modified usage of the bar clamp, the fixed jaw and the movable jaw are arranged to face away from each other whereby the bar clamp may be utilised as a spreader to force work pieces apart.

In order to cater for work-pieces of different sizes, it is proposed in the identified US Patents that one slide bar may be exchanged for a slide bar of the appropriate size. This means that a workman must obtain several slide bars in addition to a standard quick action bar clamp in order to undertake a full range of work requirements.

Therefore, it is an object of the present invention to provide an improved quick action bar clamp that is readily adjustable to cater for work-pieces of different sizes.

Consequently, the present invention conveniently provides a quick action bar clamp comprising a slide bar, a first jaw member mounted at an end portion of the slide bar and a

second jaw member mounted on the slide bar for relative movement with respect to the first jaw member whereby, when the bar clamp is in use in a first mode of operation, the second jaw member is caused to be moved towards the first jaw member to clamp work-pieces there-between and when the clamp bar is in use in a second mode of operation, the second jaw member is caused to be moved away from the first jaw member to hold work-pieces in a spaced apart relationship, characterised in that the bar clamp comprises a slide bar extension, whereby, when the bar clamp is in use, in either mode of operation thereof, work-pieces of different sizes are clamped together or spaced apart one relative to the other.

Conveniently, the slide bar extension is mounted on the slide bar by connector means.

In one preferred embodiment provided by the present invention, the connector means comprises at least one side plate fixedly mounted on the slide bar extension, wherein the at least one side plate is conveniently provided with on inwardly facing slot for engagement, in use, with a stop element provided in an end portion of the slide bar.

Preferably, there are two side plates, each of which may be provided with an inwardly facing slot for engagement, in use, with a respective stop element of the slide bar.

Conveniently, the connector means also comprises stop means to ensure the mutual alignment, in use, of the slide bar and slide bar extension.

Preferably, the stop means comprises a plate element fixedly mounted between the side plates.

In a further preferred embodiment of the present invention, the connector means comprises a sleeve member arranged, in use, to surround the side plates and an end portion of the slide bar to secure the slide bar extension to the slide bar of the quick action bar clamp.

Conveniently, the sleeve member is provided with locking means for securing the slide bar extension to the slide bar of the quick action bar clamp.

The slide bar extension conveniently comprises a plurality of positions in which, when the bar clamp and slide bar extension are in use, the first jaw member is positioned according to the size of the work-pieces to be clamped or spaced apart one relative to the other.

Preferably, the slide bar extension comprises a dowel pin at each of the plurality of positions, the dowel pins being engaged by the first jaw member according to the size of the work-pieces to be clamped or spaced apart one relative to the other.

There now follows, by way of example of the invention, a detailed description, which is to be read with reference to the accompanying drawings in which: Figure 1 is a side view of a quick action bar clamp of the invention in a first mode of operation thereof; Figure 2 is a side view of a quick action bar clamp of the invention in a second mode of operation thereof; Figure 3 is plan view of a slide bar extension provided by the invention;

Figure 4 is an underside view of the slide bar extension of Figure 3; Figure 5 is view of the slide bar extension as seen in the direction of the Arrow V in Figure 3; and, Figure 6 is a schematic exploded side view of the component parts of a slide bar extension provided by the invention.

Quick action bar clamps 2 are well known for use in clamping work-pieces together or holding work-pieces apart in a spaced relationship one from another. Generally, such quick action bar clamps comprise a slide bar 4. A first jaw member 6 mounted on the slide bar 4 and a second jaw member 8 moveably mounted on the slide bar 4 for relative movement with respect to the first jaw member 6.

The first jaw member 6 is normally located at an end portion 10 of the slide bar 4 and is retained that in position by a stop element 12 as indicated in chain dot line 14 in Figure 1. The second jaw member 8 comprises a trigger grip 16, operation of which is effective, when the quick action bar clamp 2 is in use in a first mode of operation, to move. the second jaw member 8 towards the first jaw member 6 to clamp work-pieces there-between.

The second jaw member 8 also comprises a biased locking blade 18 of known configuration, which locking blade 18 prevents movement of the second jaw member 8 away from the first jaw member 6. Release of the second jaw member 8 is achieved by finger operation of an extension portion 18a of the locking blade 18.

In a second mode of operation of the quick action bar clamp

2, the first and second jaw members 6 and 8 are arranged to face away one from the other so that operation of the trigger grip 16 causes the second jaw member 8 to move away from the first jaw member 6 to hold work-pieces in a spaced apart relationship one to the other.

The quick action bar clamp 2 normally caters for large work- pieces by exchanging one length of slide bar 4 for another with the disadvantage that several separate slide bars 4 of different lengths must be stocked.

In order to overcome the inherent disadvantage of known quick action bar clamps, the present invention provides a slide bar extension 20 for connection to the slide bar 4 of a quick action bar clamp 2, which slide bar extension 20 facilitates the use of the bar clamp 2 with a wide range work-pieces which are to be clamped together or held apart, see Figures 1 and 2.

The slide bar extension 20 is generally of the same cross- section as the slide bar 4 and is connected to the slide bar 4 by connector means 22, see Figures 1 to 6.

The connector means 22 comprises two side plates 24 and 26 formed integrally with the slide bar extension 20, the side plates 24 and 26 being located one on either side of the slide bar extension 20 as shown in Figures 3,4 and 5, the side plates 24 and 26 forming a bifurcated portion 28 of the slide bar extension 20.

Each side plate 24 and 26 is provided with an L'shaped slot 24a and 26a on inner faces 24b and 26b respectively, the purpose of which slots 24a and 26a will be described hereinafter. The slots 24a and 26a extend from upper

surfaces 24c and 26c as shown in Figures 1,2 and 3 The connector means 22 also comprises a stop means 30 provided by a plate element 32 fixedly mounted between the side plates 24 and 26 at underside surfaces 24d and 26d thereof respectively, see Figures 3 and 4. The purpose for the stop means 30 will be made clear hereinafter.

The connector means 22 further comprises a sleeve member 34, which is of an open ended, rectangular box-like configuration, see Figure 6, and is arranged, in use to surround the side plates 24 and 26 and the end portion 10 of the slide bar 4 as explained in detail hereinafter.

The sleeve member 34 is provided with a locking means 36 comprising a hexagonal headed screw 38, see Figures 3 and 4.

The slide bar extension 20 is provided with a plurality of dowel pins 40 that extend on either side of the slide bar extension 20 as shown in Figures 3 and 4 for a purpose to be described. The pins 40 correspond to the stop element 12 of the slide bar 4 and facilitate the positioning of the first jaw member 6 in a plurality of positions for a purpose to be described.

In using the slide bar extension 20 with a conventional slide bar 4, an operative removes the first jaw member 6 from the slide bar 4 by moving a latching member 42 downwards, see Figure 1. The slide bar 4 is then offered up to the bifurcated portion 28 of the slide bar extension 20 so that the stop element 12 enters into upper end portions of the L'shaped slots 24a and 26a and the slide bar 4 is brought into substantial alignment with the slide bar extension 20, see Figure 1.

The plate element 32 of the stop means 30 prevents the slide bar 4 from moving out of alignment with the slide bar extension 20 until the sleeve member 34 is moved from an inoperative position into an operative position as shown in Figure 1. In its operative position, the sleeve member 34 surrounds the side plates 24 and 26 and the end portion 10 of the slide bar 4, see Figure 1.

The sleeve member 34 is secured in its operative position by the hexagonal headed screw 38 and the operative places the first jaw member 6 on the slide bar extension 20 at one of the positions coincident with the size of work-pieces to be clamped between the first and second jaw members, the first jaw member 6 being fixed in situ by effecting upward movement of the latching member 42, which latches onto one of the dowel pins 40 to prevent movement of the first jaw member 6.

The quick action bar clamp 2, now provided with the slide bar extension 20, can be used in a first mode of operation to clamp work-pieces together in known manner, see Figure 1.

By reversing the orientation of the first and second jaw members 6 and 8 as shown in Figure 2, the quick action bar clamp 2, now provided with the slide bar extension 20, can be used in a second mode of operation to hold work-pieces apart one from the other.

It will be appreciated that work-pieces clamped or held apart by the quick action bar clamp 2, provided with the slide bar extension 20, may be subjected to any appropriate operation in keeping with the conventional uses of a traditional quick action bar clamp.

It is envisaged within the scope of the present invention that more than one slide bar extension may be used in series.

If required, components of the slide bar extension may be heat treated as appropriate.

Further modifications to the exemplified slide bar extension may be made within the scope of the invention claimed herein.

For example, in an alternative embodiment of the invention, not shown, the dowel pins 40 and the latching member 42 are omitted and the first jaw member 6 is provided with a spring loaded peg for engagement in one of the apertures that are provided for the dowel pins 40. In addition, in the alternative embodiment, the side plates 24 and 26 are each provided with a second'L'shaped slot, which slots serve the same purpose as the'L'shaped slots 24a and 26a of the first embodiment provided by the present invention.