GB1559515A

GB1559515A - Fastening equipment

Info

Publication number: GB1559515A
Application number: GB4252276A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-11-14
Filing date: 1976-10-13
Publication date: 1980-01-23
Also published as: CH611986A5; AT349193B; FR2328877B2; ATA764876A; NL7611573A; NL181129C; FR2328877A2; NL181129B

Abstract

After introduction into the bore, the dowel sleeve (1) is held by a cap (6) which seals off the bore with a frictional fit. An envelope (7) in the form of a sack encloses the dowel sleeve and is fastened between the cap (6) and the bore wall. The curable binder is injected, via an injection device (10), through the dowel sleeve (1) into the envelope (7) which is then filled and expanded. In this manner, an anchoring body, comprising cured binder, for the dowel sleeve is formed behind the bore. <IMAGE>

Description

(54) FASTENING EQUIPMENT (71) I, ARTUR FISCHER, a German Citizen, of D-7241 Tumlingen, Gde. Waldachtal, Weinhalde 34, Germany. do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement This invention relates to fastening equipment especially for cavity bricks.

The Complete Specification of my Co- pending British Patent Application No.

46198/75 (1 534 702) relates to a method of anchoring a fixing plug in a bore in masonry using a bush having a bore for receiving one end portion of the fixing plug, the fixing plug being such that, prior to anchoring, a space exists between the wall of the masonry bore and the outer surface of the fixing plug, the method comprising inserting the fixing plug into the masonry bore; holding the fixing plug substantially centrally within the masonry bore by means of the bush, the bush engaging the mouth of the masonry bore, substantially closing the gap between the fixing plug and the mouth and being provided with at least one narrow air-vent for venting the said space: and introducing a fixing agent into the said space via a hole in the bush or in the plug.

This method of anchoring has the advantage that objects may be securely fixed to walls which are very porous or which have cavities, and therefore offer only slight opportunity for an expansible element to obtain a grip.

In the case of walls with very large cavities, the consumption of fixing agent to fill up the cavity is of course very great.

It is, therefore. the aim of the invention to provide fastening equipment which can be used with the method of my copending Application No. 46198/75 (1 534 702) and which uses less fixing agent.

The present invention provides fastening equipment comprising a hollow fixing plug, an expansible sheath for the plug and a bush, the bush having a bore for receiving an end portion of the fixing plug and being for use in holding the fixing plug in a hole in a wall or panel with part of the fixing plug extending rearwardly of the wall or panel, the bush substantially sealing off the hole from the outside and the fixing plug having a hole to allow injection of fixing agent into the sheath, which, in use, surrounds the said part of the plug, to expand the sheath.

To carry out an anchoring operation using this fastening equipment, a bore corresponding to the outer diameter of the bush is drilled in, for example, a wall made of cavity bricks, into which bore the fixing plug, with the bush mounted on it, is then inserted. The annular gap between the plug and the wall of the bore is closed off by the bush. At the same time the plug is centered in the bore and held in Dosition by the bush.

Fixing agent is now injected by means of an injection device through the hole in the plug and into the sheath which surrounds the plug. The sheath is thereby filled with fixing agent so that it expands and forms. when the fixing agent has hardened, a counter-abutment area behind a cross-piece of the brick. Consequently.

withdrawal of an article secured to the wall of the brick by the plug is prevented.

The provision of a sheath makes it unnecessary completely to fill up the cavity, especially in the case of bricks with very large cavities, which can represent a considerable saving of fixing agent.

The sheath may be so attached to the bush and/or olug that the oDen end portion of the sheath can be inserted with the bush into the mouth of the bore.

Advantageously, the sheath is provided with a plurality of small apertures which are sized to permit venting of the sheath - necessary to facilitate complete filling of the sheath and to promote rapid hardening of the fixing agent - but to prevent egress of the fixing agent.

Because of the expansion of the sheath when the fixing agent is injected, the sheath is put under tension which, after completion of the injection process and removal of the injection pressure, may possibly cause the fixing agent to be forced at least partially back into the plug. In order to prevent this flow back of fixing agent, the hole in the plug which may be constituted simply by an open end of the plug - is provided with a valve closure.

The valve closure permits passage of the fixing agent into the sheath but prevents its egress from the sheath into the plug. Further, the provision of the valve closure enables very thin liquid fixing agents to be used without fear of such fixing agents flowing back. The advantages of such thin liquid fixing agents are that they are easy to inject and have a long hardening time.

Preferably, the valve closure is constituted by a piece of rubber tubing stretched over the plug to cover the hole. Owing to the resilience of the tubing it lifts away from the plug to allow the injected fixing agent to flow out of its ends and into the sheath. When injection is complete the tubing re-positions itself against the plug and in so doing seals off the hole so that no fixing agent can flow back into the plug.

Advantageously, the equipment further comprises a cup-shaped member which, in use, is placed as a friction fit on the insertion end of the plug, the sheath being trapped between the cup-shaped member and the insertion end of the plug.

With this cup-shaped member, instead of the sheath being held at one end of the plug, it is now held at both ends. The sheath is thereby compelled to expand substantially radially between its ends. At the same time, a large part of the weight of the fixing agent with which the sheath is filled is supported by the cup-shaped member, so that with the same expansibility of the sheath an almost uniform distribution of fixing agent around the plug is achieved even where the fastening arrangement is anchored in vertical walls.

Since only the counter-abutment area behind the cross-piece of the cavity brick is of importance for resisting extraction forces, in spite of a small quantity of fixing agent being used, an increase in the resistance of extraction is achieved on account of its more uniform distribution around the plug.

Preferably, the cup-shaped member is provided with at least one aperture in its side wall, the or each aperture extending from the open end of the cup-shaped member almost to its base. This development comes into play when the insertion end of the plug is open and this opening serves as the said hole for the injection of the fixing agent into the sheath. Whilst the insertion end of the plug is closed by the sheath, the aperture or apertures in the side wall of the cup-shaped member permit, as the fixing agent is being injected, the sheath in this region to lift away from the end of the plug -- owing to the injection pressure - and in this way for a passage for the fixing agent to be formed.

Upon completion of the injection process, the sheath contracts against the outer surface of the plug in the region(s) of the aperture(s) in the cup-shaped member, so that the fixing agent is prevented from flowing back. A simple valve closure is thus produced in this way.

Advantageously, the sheath is so constructed that expansion of it in a direction along the axis of the plug is restricted.

By restricting expansion of the sheath in a direction along the axis of the plug any fixing agent injected into the sheath will cause expansion of the sheath in a radial direction relative to the axis of the plug. Consequently, less fixing agent will be required to produce a given radial dimension of the sheath. However this in no way reduces the security of an article secured to the wall by the plug since it is the radial extent of the expanded sheath which is the important factor in determining that security.

Preferably, the material from which the sheath is made ensures that expansion of the sheath in a direction along the axis of the plug is restricted.

Advantageously, the material is woven.

Advantageously ,a respective one of the warp or weft is woven more tightly than the other.

Advantageously, the sheath is made of an anisotropic fabric and can expand only radially relative to the plug. By making the sheath of a fabric. it is not only more resistant to damage, but also permeable to air, so that the venting necessary for the complete filling of the sheath is guaranteed, and a more rapid hardening of the fixing agent results.

Advantageously, a circumferential groove is provided in the outer surface of the bush into which groove a spring ring may be inserted to fasten the sheath to the bush. Preferably, the circumferential groove is situated adjacent to that end of the bush which, in use, is remote from the insertion end of the plug.

The fastening of the sheath in the region of said end of the bush (the visible end) makes it possible, even where the plug is anchored in a structural part with a a thin-walled facing panel. for the sheath to be able to expand directly behind such a facing panel. Moreover, fastening of the sheath in that region also ensures that the sheath is clamped in place not only by the spring ring but also by the clamping action arising from insertion of the bush into the bore of the facing panel.

Advantageously, the sheath is secured to the bush by stretching its mouth portion over the outer circumferential surface of the plug.

Three forms of fastening equipment, each constructed in accordance with the invention, will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a cross-section through the first form of fastening equipment, shown anchored in a cavity brick wall; Fig. 2 is a cross-section through the second form of fastening equipment, shown anchored in a cavity brick wall; Fig. 3 is a cross-section taken on the line I-II of Fig. 2: and Fig. 4 is a cross-section taken through the third form of fastening equipment, shown anchored in a cavity brick wall.

Referring to the accompanying drawings, Fig. 1 shows equipment having a fixing plug 1, whose front (insertion) end is squashed flat and is bent in the manner of a harb 2. The barb 2 increases the resistance to withdrawal when the plug 1 is anchored. The rear end 4 of the plug 1 has a smaller diameter than the main portion of the plug to facilitate the tapping of an internal thread 3 for a fastening screw. A bush 6, which closes the mouth of the bore leading to a cavity 5 of a cavity brick 14, is placed on this reduced diameter section 4 of the plug, the external diameter of the bush being matched to the diameter of the bore so that it can be fixed in the bore. The bush 6 has a sealing lip 6a which serves to ensure that the bore is sealed even when its mouth has a broken-away edge. A flexible sheath 7 is place round the plug 1 prior to the insertion of the plug and the bush 6 in the bore.

Before fixing agent is introduced into the sheath 7, an injection sleeve 41 is inserted into the inner bore 40 of the plug 1. the leading end of the injection sleeve abutting agains the end of the inner bore of the plug so as to provide a seal. The fixing agent is now injected through the injection sleeve 41 by an injection device 10. The fixing agent passes through outlet apertures 22 in the plug 1 and into the cavity 5. During the injection process the sheath 7 is filled with fixing agent and expands so that after the fixing agent has hardened it provides a large and symmetrical counter-abutment area behind the wall 13 of the brick. Complete filling of the sheath 7 is rendered possible by air vents 8 which are distributed over its entire outer periphery.

A piece of rubber tubing 9 is stretched over the apertures 22 so as to cover them.

During the injection process this tubing 9 is lifted away from the apertures 22 owing to the injection pressure, and in this way enables the sheath 7 to be filled. However, after completion of the injection process, the tubing 9 seals off the apertures 22 so that no fixing agent can flow back into the inner bore 40 of the plug 1.

After the injection and hardening of the fixing agent, the injection sleeve 41 with the core 42 of hardened fixing agent contained in it is removed. The inner bore 40 of the Dlug 1 with its internal thread 3 is now free for receiving a fastening screw which may be used, for example, to clamp an object to the wall 13 of the brick.

The fastening equipment illustrated in Fig. 2 is very similar to that shown in Fig. 1 and like reference numerals have been used for like parts. Here, however, the portion of the plug 1 which projects into the cavity 5 is provided with several annular indentations 2' to increase the anchoring effect.

In this case, the fixing agent passes through the open insertion end of the plug and into the sheath 7. To stabilise the sheath 7 and to provide a bulge-like radial expansion of the sheath, a cupshaped member 9' is placed upon the insertion end of the plug 1. which member clamps the sheath 7 firmly to the plug in the region of its insertion end.

By an appropriate snug fit the cup-shaped member 9' is so held on the plug 1 that, between the closed end face 11 of the member 9' and the insertion end of the plug, a space is formed. The cup-shaped member 9' is provided with an aperture 12 in its side wall, into the region of which aperture the sheath 7 may lift away from the plug 1 (see Fig. 3) during the injection process to create a passage for the fixing agent. After the injection process and the bulge-like expansion of the sheath 7, the sheath contracts against the plug in the region of the aperture 12 of the cup-shaped member 9', and in this way prevents the fixing agent from flowing back into the inner bore 40 of the plug. The bulge-like expansion of the sheath 7 results in a large and symmetrical counter-abut ment area behind the cross-piece 13 of the cavity brick 14.

Th fastening equipment illustrated in Fig. 4 is again very similar to that shown in Fig. 1 and again like reference numerals have been used for like parts. Here, however, the sheath 7 is made of an anisotropic fabric which can expand only in a radial direction. Such a fabric may, for example, be produced by weaving its weft threads loosely and its warp threads tightly. The sheath 7 is joined to the bush 6 by a spring ring 43 which snaps into an annular groove 45 arranged in the outer circumferential surface of the bush in the region of the latter's visible end face 44.

Not only is the fibre sheath 7 more resistant to damage, it is also more permeable to air than sheaths made of synthetic material. Thus, the sheath 7 can be rapidly filled owing to the improved venting, and the fixing agent hardens quickly. The anisotropic nature of the fibre sheath 7 results in a uniform bulge-like filling of the sheath which ensures that a large and symmetrical counter-abutment area is formed behind the cross-piece 13 of the brick 14.

Reference is directed to the Complete Specification of our copending British Patent Application No. 24422/77 Serial No. 1 559 516 which is also concerned with fastening equipment of the type described and illustrated in Fig. 4.

WHAT I CLAIM IS: 1. Fastening equipment comprising a hollow fixing plug, an expansible sheath for the plug and a bush, the bush having a bore for receiving an end portion of the fixing plug and being for use in holding the fixing plug in a hole in a wall or panel with part of the fixing plug extending rearwardly of the wall or panel, the bush substantially sealing off the hole from the outside and the fixing plug having a hole to allow injection of fixing agent into the sheath, which, in use, surrounds the said part of the plug, to expand the sheath.

2. Fastening equipment as claimed in in claim 1, wherein the sheath is provided with a plurality of small apertures which allow venting of the sheath but prevent egress of the fixing agent.

3. Fastening equipment as claimed in claim 1 or claim 2, wherein the hole is provided with a valve closure for preventing the fixing agent from flowing back into the interior of the plug.

4. Fastening equipment as claimed in claim 3, wherein the valve closure is constituted by a piece of rubber tubing stretched over the plug to cover the hole in the plug.

5. Fastening equipment as claimed in any one of claims 1 to 4, further comprising a cup-shaped member which, in use, is placed as a friction fit on the insertion end of the plug, the sheath being trapped between the cup-shaped member and the insertion end of the plug.

6. Fastening equipment as claimed in claim 5, wherein the cup-shaped member is provided with at least one aperture in its side wall, the or each aperture extending from the open end of the cup-shaped member almost to its base.

7. Fastening equipment as claimed in any one of claims 1 to 6, wherein the sheath is so constructed that expansion of it in a direction along the axis of the plug is restricted.

8. Fastening equipment as claimed in claim 7, wherein the material from which the sheath is made ensures that expansion of the sheath in a direction along the axis of the plug is restricted.

9. Fastening equipment as claimed in claim 7 or claim 8, wherein the material is woven.

10. Fastening equipment as claimed in claim 9, wherein a respective one of the warp or weft is woven more tightly than the other.

11. Fastening equipment as claimed in any one of claims 1 to 10, in which the sheath is made of an anisotropic fabric and can only expand radially relative to the plug.

12. Fastening equipment as claimed in any one of claims 1 to 11, wherein a circumferential groove is provided in the outer surface of the bush into which groove a spring ring may be inserted to fasten the sheath to the bush.

13. Fastening equipment as claimed in claim 12, wherein the circumferential groove is situated adjacent to that end of the bush which, in use, is remote from the insertion end of the plug.

14. Fastening equipment as claimed in any one of claims 1 to 13, wherein the sheath is secured to the bush by stretching its mouth portion over the outer circumferential surface of the plug.

15. Fastening equipment as claimed in any one of claims 1 to 14 and substantially as hereinbefore described with reference to, and as shown in, Fig. 1, Figs. 2 and 3.

or Fig. 4 of the accompanying drawings.

16. A method of anchoring a fixing plug, the method employing equipment as claimed in any one of claims 1 to 14.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. ment area behind the cross-piece 13 of the cavity brick 14. Th fastening equipment illustrated in Fig. 4 is again very similar to that shown in Fig. 1 and again like reference numerals have been used for like parts. Here, however, the sheath 7 is made of an anisotropic fabric which can expand only in a radial direction. Such a fabric may, for example, be produced by weaving its weft threads loosely and its warp threads tightly. The sheath 7 is joined to the bush 6 by a spring ring 43 which snaps into an annular groove 45 arranged in the outer circumferential surface of the bush in the region of the latter's visible end face 44. Not only is the fibre sheath 7 more resistant to damage, it is also more permeable to air than sheaths made of synthetic material. Thus, the sheath 7 can be rapidly filled owing to the improved venting, and the fixing agent hardens quickly. The anisotropic nature of the fibre sheath 7 results in a uniform bulge-like filling of the sheath which ensures that a large and symmetrical counter-abutment area is formed behind the cross-piece 13 of the brick 14. Reference is directed to the Complete Specification of our copending British Patent Application No. 24422/77 Serial No. 1 559 516 which is also concerned with fastening equipment of the type described and illustrated in Fig. 4. WHAT I CLAIM IS:

1. Fastening equipment comprising a hollow fixing plug, an expansible sheath for the plug and a bush, the bush having a bore for receiving an end portion of the fixing plug and being for use in holding the fixing plug in a hole in a wall or panel with part of the fixing plug extending rearwardly of the wall or panel, the bush substantially sealing off the hole from the outside and the fixing plug having a hole to allow injection of fixing agent into the sheath, which, in use, surrounds the said part of the plug, to expand the sheath.

or Fig. 4 of the accompanying drawings.