GB2131858A

GB2131858A - A cramp

Info

Publication number: GB2131858A
Application number: GB08235465A
Authority: GB
Inventors: Brian Robinson
Original assignee: Catnic Components Ltd
Current assignee: Catnic Components Ltd
Priority date: 1982-12-13
Filing date: 1982-12-13
Publication date: 1984-06-27

Abstract

A cramp 1 for securing a window or door frame 2 in position in masonry 3 has limbs 4 and 5 at an angle and strengthening means 9 at the junction of the limbs and flanges 11 which resist bending. The cramp 1 is made integrally from a stainless steel blank. <IMAGE>

Description

SPECIFICATION A cramp Technical field of invention The invention relates to a cramp for securing a window or door frame in position in surrounding masonry.

According to the invention there is provided a cramp for securing a window or door frame in position in surrounding masonry, comprising two limbs one of which is at an angle to the other and is adapted to be secured to a frame and the other of which is adapted to the keyed in mortar of masonry adjacent the frame, and strengthening means which extend between the two limbs for resisting relative movement of the two limbs in use.

The other limb may be adapted by one or more tabs inclined to the plane of the limb for keying in mortar of masonry surrounding the frame. This construction provides a relatively simple way of providing for a positive binding of the mortar and cramp.

The strengthening means may comprise one or more channel means which may be open in a direction away from the angle between the two limbs. The or each channel provides a strengthening of the cramp in compression.

The one limb may be wider than the other limb.

This construction provides for a secure anchorage, via the means for securing the one limb to the frame, for screws, nails, or the like.

The other limb may be substantially rectangular, and at least one lateral edge thereof may be inclined to the plane of that limb. The or each edge may be inclined upwardly, as considered in use, at an angle of substantially 900 to the plane of the other limb. Both edges may be so inclined. This construction provides a relatively simple construction for strengthening the cramp against side or torsional stresses. Such stresses are resisted in use.

The transition from the lateral edge of the one limb to the corresponding lateral edge of the other limb may be a curve, preferably arcuate. This provides a relatively simple way of forming the cramp from a blank of planar metal, and avoids the development of point stresses in the transitional area between the one limb and the other.

The cramp may be made from a single blank of metal, preferably stainless steel.

The invention extends, it will be understood, to a frame secured in position by a cramp as hereinbefore defined.

A cramp embodying the invention is hereinbefore described, by way of example, with reference to the accompanying drawings.

Brief description of drawings Figure 1 is a side view of the cramp; Figure 2 is a plan view of the cramp of Fig. 1; Figure 3 is an enlarged sectional view of part of the cramp showing a tab; Figure 4 is a perspective view, to an enlarged scale as compared with Figs. 1 and 2, showing the cramp of those Figs. in use, and Figure 5 is a plan view of a blank from which the cramp is made.

Referring to the drawings, there is shown a cramp 1 for securing a (wooden in this case) window or door frame 2 in position in surrounding masonry 3 such as a wall comprising superimposed rows of bricks, blocks or the like, which rows are separated by mortar. The cramp 1 comprises two limbs one 4 of which is at an angle, in the embodiment shown substantially a right angle, to the other limb 5. The one limb 4 is adapted to be secured to the frame 4 by through holes 6 through each of which a securing device such as a screw or nail 7 is passed (Fig. 5). The other limb 5 is adapted to be keyed in a mortar layer between two adjacent superposed courses of bricks by means of a plurality of, in this case six, tabs 8 each of which is struck out of the other limb 5 and is inclined, at 400 in the embodiment shown, to the plane of that other limb 5.The cramp 1 also has strengthening means in the form of two substantially parallel channel means 9 which extend over the whole length of the one limb 4, across the transitional zone 10 between the two limbs 4 and 5 and into the other limb 5, where they terminate at a position just inboard of upturned flanges 11 which are parallel and which extend along the other limb 5 to the free end thereof. The channel means 9 are thus open in a direction away from the angle between the limbs 4 and 5. The flanges 11 also provide the strengthening means and resist side or tensional forces tending in use to twist the cramp 1 if the frame and/or masonry move relative to one another.

The channel means 9 resist any motion to "open" or "close" the angle between the limbs, in other words compression or tensional forces.

The flanges 11 have a height which is just less than that of the part of the respective channel means 9 which extends into the other limb 5.

The one limb 4 is wider than the other limb 5, to provide a sound bearing surface of the one limb 4 against the frame 2 with sufficient lateral extent of material outwardly of the screws 7 to obviate buckling or distortion, the holes 6 passing through and having a diameter equal is the width of, the respective channel means 9.

The boundary edges of the one limb 4 merge with a curved (concave) edge 13 in the transitional zone 10 which in turn merge with the respective flanges 11 of the respective lateral edges of the other part 5.

The cramp 1 is formed integrally from a single blank 12 of metal, in this case austenitic stainless steel to BS 1449 part 2 and BS 970 part 4. The steel has a minimum 18/8 composition, and free machining specification. The thickness of the blank 12 is 0.6 mm which contrasts with a material thickness of in the region of 2.6 mm in prior cramps.

The blank 12 has two cut-outs 14 to form the curved transition 10 between the one limb 4 and the other limb 5, a transverse fold line 15 to provide a fold for the 900 angle between the limbs and longitudinal fold lines 16 tangential to the arcuate cut-outs 14 to provide the flanges 1 1 when the metal of the blank 12 is folded up (out of the plane of the paper towards the viewer in Fig. 5). Semicircular slits 16 are formed to provide a semi-circular piece of metal which is also turned up, like the flanges, to provide the tabs 8. Further, there are press or fold lines 17 where the channel means 9 are formed.

The cramp 1 is formed from the (rectangular) blank 12 by a simple stamping and folding operation. The cramp 1 formed is used by securing it to the outside of the frame 2 by the screws 7 so that the one 4 limb is substantially parallel thereto and the other limb 5 lies on the upper (as viewed in Fig. 4) surface of a brick of the masonry wall 3 adjacent the frame. Mortar is thus laid in place on the course so embedding the other limb 5 which is united with the mortar by the tabs 8 and flanges 11 which are embedded therein. The mortar also passes through the limb through the holes left when the tabs are formed.

The cramp 1 thus becomes an integral part of the masonry. Any relative movement owing to "settling" or shrinkage is resisted by the cramp 1 which therefore acts tightly to bind the frame 2 and masonry 3 together, whether compression, tensional, or torsional become applied. The cramp 1 is thus strong, and corrosion resistant as it is of stainless steel.

The expression masonry used herein is intended to cover brickwork, blockwork and the like laid in superimposed courses between adjacent one of which mortar, cement or the like is laid.

Claims

1. A cramp for securing a window or door frame in position in surrounding masonry, comprising two limbs one of which is at an angle to the other and is adapted to be secured to a frame and the other of which is adapted to be keyed in mortar of masonry adjacent the frame, and strengthening means which extend between the two limbs for resisting relative movement of the two limbs in use.

2. A cramp according to Claim 1, the other limb being adapted by one or more tabs inclined to the plane of the limb for keying in mortar of masonry surrounding the frame.

3. A cramp according to Claim 1 or Claim 2, the strengthening means comprising one or more channel means which is or are open in a direction away from the angle between the two limbs.

4. A cramp according to any preceding Claim, the one limb being wider than the other limb.

5. A cramp according to any preceding claim, the other limb being substantially rectangular, at least one lateral edge thereof being inclined to the plane of that limb.

6. A cramp according to Claim 5, the or each edge being inclined upwardly, as considered in use, at an angle of substantially 900 to the plane of the other limb.

7. A cramp according to Claim 5 or Claim 6, both each being inclined.

8. A cramp according to any of Claims 4 to 7, the transition from the lateral edge of the one limb to the corresponding lateral edge of the other limb being a curve.

9. A cramp according to Claim 8, the curve being arcuate.

10. A cramp for securing a window or door frame in position in surrounding masonry, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

1 A frame secured in position in surrounding masonry by a cramp according to any preceding claim.