GB2352203A - Sash cramps - Google Patents

Abstract

Sash cramps comprise a support bar 2, a line of spaced holes 3 in the bottom face of the support bar, a first jaw 4 and a moveable jaw 5 located on the bar. At least the moveable jaw has a box-like slider to fit over the bar and an inner projection 10 on the lower face of the box-like slider for selective engagement with one or other of the holes in the bar. A means of holding the projection in engagement with a selected hole, may comprise a leaf spring 7.

Description

2352203 SASH CRAMPS This invention relates to sash cramps.

Historically, sash cramps have been constructed as a support bar of an appropriate length, with a first jaw and a moveable second jaw. To allow the sash cramp to grip a wide variety of products of different width and lengths, and to avoid having a screw adjustment for the moveable second jaw of inordinate length, it is known for at least the moveable jaw to be repositionable along the length of the bar, to position it at a distance from the first jaw to suit a particular product to be clamped, and such that a relatively short screw adjustment can be provided to allow the jaw face to be withdrawn to a position where the product can be positioned between the moveable jaw face and the fixed jaw face, and then driven forward to clamp the product between the two jaw faces.

Hitherto, it has traditionally been so that at least the moveable jaw, and possibly also the fixed jaw is or are located along the length of the bar and attached to the bar by pins or bolts selectively engaging strategically spaced pairs of holes in the bar side faces along the length of the bar. Thus, two holes must be drilled at each location, with considerable accuracy to ensure that a pin or bolt can pass through both holes. To allow adjustment, the pin or bolt must be removed, and can become lost. Equally, it is usual for the jaws to have side cheeks or flanges to lie alongside the bar, and when the pins or bolts are removed, the jaws become detached.

The object of the invention is to provide an improved construction of sash cramp.

According to the present invention, a sash cramp comprises a support bar, a line of spaced holes in the bottom face of the support bar, a first jaw and a moveable jaw located on the bar, at least the moveable jaw having a box-like slider to fit over the bar, an inner projection on the lower face of the box-like slider for selective engagement with one or other of the holes in the bar, a means of holding the projection in engagement with a selected hole, and a means of enabling the projection to disengage from the hole.

Preferably, the moveable jaw has an upstanding flange with a threaded hole to receive a threaded screw stem, at the end of which is a jaw face, whereby with the moveable jaw located as required on the bar, a fine adjustment of the moveable jaw face is allowed by the screwed stem to lock and release a product positioned between the fixed and moveable jaw.

To allow the engagement and disengagement of the inner projection on the slider from a hole in the bottom face of the bar, the slider may have a larger height than the bar, and have a resilient means to hold the slider in an elevated position, and hence the projection in a co-operating hole, the resilient means allowing the slider to be depressed to disengage the projection from that hole, and slide along the bar to another required location, when release of the slider allows it to rise for the projection to engage in the next required hole.

Given the bulk needed for the moveable jaw of a sash cramp, it is preferred that a fulcrum is provided to the rear of the moveable jaw, to rest on the top surface of the bar and assist in taking the weight of the moveable jaw, and to have a leaf spring attached to the inner top surface of the slider with its free end resting on the top surface of the bar. When repositioning of the moveable jaw is needed, the forward end is simply pushed down such that the moveable jaw pivots about the fulcrum to cause the projection to disengage from its hole, in which condition, the moveable jaw can be slid along the bar to relocate it, and released to allow the leaf spring to lift the forward end of the moveable jaw and cause the projection to engage the required hole in the bar.

This arrangement not only brings about the notable saving by only having it drill one line of holes, but also loose pins and bolts are avoided, and the moveable jaw remains attached to the bar during its relocation.

It will be understood that whilst the fixed jaw can be permanently secured to one end of the bar, it can be similarly constructed to the moveable jaw, to allow both of the fixed and moveable jaws to be strategically positioned on the bar.

In accordance with a further feature of the invention both of the first jaw and moveable jaw assemblies are capable of being removed from the support bar, and this lends itself to a further advantage of the invention, where both heads are reversed and able to provide an outward pressure on the inner faces of parallel product members, to hold the product in place whilst required operations are effected on it. This aids considerably the holding of such as window frames whilst work is done on them.

Given the length of bar required, desirably it is formed as a box section to combine relatively light weight and strength from an appropriate alloy steel.

One example of sash cramp will now be described with reference to the accompanying drawings in which:

Figure 1 is a side elevation of a sash cramp according to the invention; Figure 2 is a plan view of Figure 1; Fi ure 3 is an underneath plan view of Figure I and 9 Figure 4 is a sectional side elevation of the sash cramp of Figure 1.

In the drawings, a sash cramp 1 has a support bar 2, a line of spaced holes 3 in the bottom face of the support bar, a first jaw 4 and a moveable jaw 5 located on the support bar, The first jaw 4 is in the form of a box-like slider dimensioned to be a loose sliding fit on the support bar 2, the box-like slider having a forward upstanding jaw face 6, and a leaf spring 7 to lie between the top plate 8 of the box-like slider and the top face of the support bar 2. On the bottom plate 9 of the box-like slider, a projection 10 is provided to locate in a selected one of the holes 3 in the bottom plate of the support bar.

Given the bulk needed for the first jaw, a fulcrum I I is provided inwardly of the top plate 8, to bear on the top plate of the support bar 2, and assist in taking its weight.

The moveable jaw 5 has a jaw plate 12 on a generally U-shaped forward member 13 extending around the support bar 2, and a rearward box-like slider 14 with an upstanding flange with a threaded hole 16 for the passage of a drive screw stem 17 extending from a handle 18 to a rotatable connection 19 to the rear of the jaw plate 12. Within the box-like section 14 is a leaf spring 20 bearing on the top face of the support bar, and on the bottom plate 21 of the box-like section 14 is a projection 22 to engage a selected one of the holes 3 in the bottom plate of the support bar 2.

Here again, the bulk of the box-like slider and the U-shaped forward member is such that a fulcrum 23 is provided rearwardly of the box-like section 14, to bear against the top surface of the support bar 2 and assist in taking its weight. Once the box-like section is secured in place, the U-shaped forward member 13 and its jaw plate 12 can be moved relative to the box-like section 14.

To enable the sash cramp to grip a product, the box-like sectioned first jaw 4 with its jaw -4plate 6 can be depressed against the action of the spring 7 and pivoted about the fulcrum 11 to bring the projection 10 clear of the bottom plate of the support bar 2, and allow the first jaw 4 to be positioned on the support bar as required, when released the spring 7 causes the box-like section to pivot upwardly and bring its projection 10 into register with a selected hole 3 in the 5 bottom plate of the support bar 2.

Similarly, the moveable jaw 5 can be depressed against the action of the spring 20 and pivot about its fulcrum 23, to bring its projection 22 clear of the bottom face of the support bar 2, when it can be positioned on the support bar at a distance from the first jaw greater than the width of the product to be held, by an amount less than the length of the screw stem 17. Once the moveable jaw is released, it moves under the spring to pivot about the fulcrum 23, and bring the projection 22 into a register with a selected hole 3 in the bottom plate of the support bar 2.

A product can now be presented to the sash cramp and positioned between the jaw plates 6 and 12, and the moveable jaw plate 12 driven forward by the screw stem 17 to apply a clamping force to be applied to the product to hold it firm whilst any and all operations required are performed on the product.

The invention, in most simple and efficient manner, allows the positive clamping of any product within the length of the support bar, by way of members that have no separate, removable components, to lock and unlock them from the support bar.

Claims (8)

1. A sash cramp comprises a support bar, a line of spaced holes in the bottom face of the support bar, a first jaw and a moveable jaw located on the bar, at least the moveable jaw having a box-like slider to fit over the bar, an inner projection on the lower face of the box-like slider for selective engagement with one or other of the holes in the bar, a means of holding the projection in engagement with a selected hole, and a means of enabling the projection to disengage from the hole.

2. A sash cramp as in Claim 1, wherein the first jaw is also a moveable jaw, and has a box-like slider to fit over the bar, an inner projection on the lower face of the box-like slider for selective engagement with one or other of the holes in the bar, a means of holding the projection in engagement with the selected hole, and a means of enabling the projection to disengage from the hole.

3. A sash cramp as in Claim 1 or Claim 2, wherein at least the moveable jaw has an upstanding flange with a threaded hole to receive a threaded screw stem, at the end of which is a jaw face, whereby with the moveable jaw located as required on the bar, a fine adjustment of the moveable jaw face is allowed by the screwed stem to lock and release a product positioned between the fixed and moveable jaw.

4. A sash cramp as in any of Claims 1 to 3, wherein to allow the engagement and disengagement of the inner projection on the slider from a hole in the bottom face of the bar, the slider may have a larger height than the bar, and have a resilient means to hold the slider in an elevated position, and hence the projection in a co-operating hole.

5. A sash cramp as in Claim 4, wherein the resilient means is a leaf spring.

6. A sash cramp as in any of Claims 1 to 5, wherein a fulcrum is provided to the rear of the moveable jaw, to rest on the top surface of the bar and assist in taking the weight of the moveable jaw.

7. A sash cramp as in any of Claims 1 to 6, wherein the first jaw and moveable jaw assemblies are capable of being removed from the support bar.

8. A sash cramp substantially as hereinbefore described with reference to the accompanying drawings.