GB2276689A

GB2276689A - Securing fasteners in friable sheet material

Info

Publication number: GB2276689A
Application number: GB9402941A
Authority: GB
Inventors: David Dennis Dunkley; Michael Kenny
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-02-17
Filing date: 1994-02-16
Publication date: 1994-10-05
Anticipated expiration: 2014-02-16
Also published as: GB2276689B; GB9402941D0

Abstract

A device for securing fasteners in friable sheet material comprises a tapering of cylindrical body 10 having an external screw thread 16, a head 12 for receiving a fastener and with a screwdriver receiving depression 22, the leading end of the body 10 being receivable in a pre-formed hole in friable sheet material so that the body 10 may be screwed into the sheet material. At least one slot 18 extends along part of the length of the body 10 dividing it into at least two sections by rupturable means in the form of a plate 26 or a nib. In use the hole is pre-formed in the sheet material making use of the screwdriver with which the device is thereafter driven into the sheet material. <IMAGE>

Description

ANCHORING FASTENERS DESCRIPTION The present invention is concerned with devices for anchoring fasteners and, more particularly with devices enabling the secure fixing of fasteners in a substrate.

Devices for the secure fixing of fasteners in substrates - and in particular in friable material sheets such as plasterboard - are well known. The friable sheet material may form walls, partitions or ceilings.

The known devices - some know as fastener anchors - are often not satisfactory in that they are expensive to produce and/or require a bore to be drilled in the sheet material in which they are to be fixed and/or they do not form a sufficiently good anchor into which a fastener such as a threaded screw or a threaded bolt may subsequently be fixed.

Where the device is of the self-tapping type and does not require a bore to be drilled it is still a timeconsuming and onerous task to fix the device in the plasterboard.

An example of the prior art is shown in European Patent No. 165,674 which discloses an anchor device having a drilling end and an exterior screw thread. The drilling end first bores a hole in the plasterboard sheets and the screw thread thereafter cuts into the bore after it has been drilled. This arrangement first removes material from the wall in a drilling step and then replaces this material with a hollow body that engages the remaining material via the screw thread. This is a time consuming and onerous task and, in any case, the anchor device is not strongly held in the wall.

In order that anchors of the type described in European Patent No. 165,674 are securely fixed in the sheet material a rotating toggle clamp bar is provided in the part of the anchor which penetrates into the wall cavity.

The toggle clamp bar lies in a longitudinal slot in the body of the anchor while it is being screwed in, the bar engaging the body of the anchor via a pin on either side which engages a complementary orifice on the inside of the slot. When a screw is inserted into the anchor it deflects the toggle clamp bar so that it extends perpendicularly to the body and engages a hole in the bar upon being screwed further into the fastener anchor to rigidly hold the bar in this position. This is a complicated arrangement which is expensive to manufacture and prone to failure.

It is an object of the present invention to provide a device for securing a fastener in friable sheet material in which a hole has been pre-formed, for example with a screwdriver, bradawl or the like.

In one aspect the invention provides a device for securing a fastener in friable sheet material comprising a generally circular in section elongate body portion having an external screw thread formed thereon, one end of the body portion having a head portion being adapted to receive a fastener and having a screwdriver - receiving depression formed therein, whilst the other end of the body portion is receivable in a pre-formed hole in friable sheet material so that the device may be securely screwed into friable sheet material.

Desirably, at least one slot extends longitudinally from said other end toward said one end at least partially along the length of the body portion and dividing the body portion into at least two sections allowing a fastener to pass therebetween, the body sections being joined at the other end of the elongate body by means rupturable, by a fastener introduced into and passed along the body portion, to allow the body sections to spread apart.

The slot or slots may end before the head portion of the device is reached so that a length of the body portion will not spread when the rupturable means are broken. If an interference fit is desired in the preformed hole such an arrangement can be desirable. The device cannot be drawn from the sheet material because the spread apart body section provide a physical barrier to withdrawal of the device through the hole as well as due to the interference fit.

Desirably, however, the slot extends along the length of the device at least as far as the screwdriverreceiving depression formed in the head portion of the device.

Preferably, the device is provided with a single slot dividing the body portion into two substantially similar parts joined by said rupturable means.

The rupturable means may comprise a plate formed integrally with and extending between said other ends of each said body section.

Advantageously, there is provided an peripheral slot in the outer surface of the body portion adjacent said plate.

The rupturable means may alternatively comprises a thin wall which carries a nib on the face thereof spaced from body portion.

The nib may extend the full width of the thin wall or extend partially across the width of the thin wall and be located generally centrally thereon.

The nib may, alternatively, extend partially across the width of the thin wall and be set at one side in line with the slot at the side and be a rectangular block of the same width as the slot.

With advantage the or each slot extends from said other end of the body portion to the head portion of the device.

Desirably, the elongate body portion is of reducing cross-section in moving from said one to said other end.

The device may be of any suitable moulded plastics material, e.g. of 50% glass filled nylon or ABS.

A membrane wall may be provided to separate the screwdriver-receiving depression in the head portion and the void within the body portion formed by the at least one slot, which membrane wall is readily pierced by a fastener introduced to the device.

The screwdriver-receiving depression in the head portion may be adapted to receive the head of a Posidrive type screwdriver of a size usable to pre-form a hole in the sheet material.

In this way a user will be encouraged to punch the hole in the sheet material with the same screwdriver but ensuring a hole of suitable small diameter is formed so that the screw thread on the body portion of the device will engage the material firmly.

In a second aspect the invention provides a method of securing a fastener in friable sheet material comprising the steps of forming an aperture in said sheet material with a screwdriver, bradawl or the like, introducing to the aperture the said other end of a device as defined above, driving the device into the aperture with a screwdriver to securely fix the device in the friable material, and then introducing a fastener into the device and driving it with a screwdriver to pass along the length of the device and past said other end thereof.

In a third aspect the invention provides a method of making a device as defined above and with a single slot from a mouldable plastics material, including the use of a two-part mould each part of which has a replaceable blade for forming one half of the slot in the device.

The above and other aspects, features and advantages of the invention will become apparent from the following description of embodiments of the invention now made with reference to the accompanying drawings in which: Figure 1 shows at A, B and C respectively part sectional side and end views of a first device embodying the invention, Figure 2 is a sectional view drawn on the line II-II of Figure 1, Figure 3 shows the device of Figure 1 being fitted into a sheet of plasterboard.

Figure 4 shows at A and B respectively part sectional side and end views of a second device embodying the invention, Figure 1 shows a device embodying the invention to comprise an elongate body portion 10 which is generally circular in section along its length and which is of reducing cross section in moving from one end at which it is provided with a head portion 12 to its other end 14.

Body portion 10 carries a screw thread 16 as illustrated which runs along the major part of its length.

A slot 18 extends longitudinally of the body portion 10 from the head portion 12 towards the end 14 of the device dividing the body portion into two substantially similar equal sections 20A and 20B.

Head portion 14 is formed with a recess 22 adapted to receive the leading end of a screwdriver 24. As illustrated recess 22 is star-shaped and is adapted to receive the complementary shaped leading end of a Posidrive-head screwdriver.

As can be seen from the Figures slot 18 extends from the end of the recess 22 to the end 14 of the device where a plate 26 runs between and is formed integrally with the two body sections 20A and 20B.

In operation, the screwdriver 24 a bradawl or the like is first (Figure 3A) used to pre-form or punch a hole 28 in plasterboard sheeting 30 spaced from similar sheeting or a conventional wall 32 by a void 34. The end 14 of the device is then placed in the hole 28 (Figure 3B) and the device is screwed into the hole 28 using the screwdriver 24 until its head 12 is flush with the surface of the plasterboard 30 and a major part of the device protrudes into the void 34.

The leading end 36 of a screw 38 passing through an item 40 to be fastened to the plasterboard is then positioned in recess 22 in the head portion 12 and screwed into the devices so that the screw penetrates slot 18.

Eventually, the leading end 36 of the screw reaches and contacts plate 26 and further use of the screwdriver causes either the plate 26 to break (Figure 3C) in two or its connection with one or other of the body sections 20A and 20B to be ruptured.

Once this happens the body sections 20A and 20B splay or spread apart as shown and the device is firmly held in the hole 28 in the plasterboard 30. If necessary, the screw can be further rotated so that its head 42 is positioned as desired - e.g. flush with the surface of the item 40.

In splaying apart the body sections 20A and 20B act to firmly hold the device in position in the plasterboard - preventing its removal from the hole 28 in which it is placed.

There is a tendency for the body sections 20A and 20B to splay apart - which is prevented by the plate 26 whilst that is intact - and their tendency to splay apart is increased by the screw 38 as it is screwed into the device.

The device is of a suitable mouldable plastics material - e.g. it may be of 50% glass filled nylon or ABS.

It will be appreciated that the device described may be modified without departing from the scope of the invention.

As described the body portion tapers in moving from the head 12 to the leading end 14 of the device but it will be seen that the cross section of the body may be constant along its length if desired.

To ease the rupture of the plate 26 from the body sections 20A or 20B a narrow peripheral slot may be provided immediately adjacent the plate as shown in dotted line at 44 in Figure 1.

Figure 4 illustrates a modified form of the device shown in Figure 1 and parts common to the two illustrated forms are given the same reference numerals.

The arrangement illustrated inn Figure 4 differs from that shown in Figure 1 principally in that the plate 26 has been replaced by a thin wall 50 at the leading end 14 of the device which has mounted on it a nib 52. As can be seen nib 52 extends across only a fraction of the diameter of the body portion but it is formed integrally with the body sections 20A and 20B.

Use of the modified form is as described above a hole is punched in a plasterboard sheet, the leading end is placed in the hole and the device is screwed into the hole. A fastener is located in the device and screwed along its length until it contacts and breaks off the nib 52 allowing the body sections 20A and 20B to splay apart.

As can be seen from the Figures the nib 52 extends across only a part of the diameter of the body portion - the remainder of the slot being covered by the thin wall 50.

As illustrated the nib 52 is set at one side in line with the slot in the body and has the form of a rectangular block of the same plastics material as the rest of the body the width of which is the same as the slot.

The nib provided on the leading end of the device may be varied - it may be located generally centrally of the body on the thin wall and it may extend the full width of the thin wall.

It will be appreciated that modifications other than those already described may be made to the arrangements embodying the present invention without departing from the scope of the invention.

Claims

CLAINS

1. A device for securing a fastener in friable sheet material comprising a generally circular in section elongate body portion having an external screw thread formed thereon, one end of the body portion having a head portion adapted to receive a fastener and with a screwdriver - receiving depression formed therein, whilst the other end of the body portion is receivable in a preformed hole in friable sheet material so that the device may be securely screwed into friable sheet material.

2. A device as claimed in Claim 1, wherein at least one slot extends longitudinally from said other end toward said one end at least partially along the length of the body portion and dividing the body portion into at least two sections allowing a fastener to pass therebetween, the body sections being joined at the other end of the elongate body by means rupturable by a fastener introduced into and passed along the body portion to allow the body sections to spread apart.

3. A device as claimed in Claim 2, when provided with a single slot dividing the body portion into two substantially similar parts joined by said rupturable means.

4. A device as claimed in Claim 2 or Claim 3, wherein said rupturable means comprises a plate formed integrally with and extending between said other ends of each said body section.

5. A device as claimed in Claim 4, wherein there is provided an peripheral slot in the outer surface of the body portion adjacent said plate.

6. A device as claimed in Claim 2 or Claim 3, wherein said rupturable means comprises a thin wall which carries a nib on the face thereof spaced from body portion.

7. A device as claimed in Claim 6, wherein said nib extends the full width of the thin wall.

8. A device as claimed in Claim 6, wherein said nib extends partially across the width of the thin wall and is located generally centrally thereon.

9. A device as claimed in Claim 2 and Claim 6, wherein said nib extends partially across the width of the thin wall and is set at one side in line with the slot at the side and is a rectangular block of substantially the width of the slot.

10. A device as claimed in any one of claims 2 to 9, wherein the or each slot extends from said other end of the body portion to the head portion of the device.

11. A device as claimed in any one of the preceding claims, wherein the elongate body portion is of reducing cross section in moving from said one to said other end.

12. A device as claimed in any one of the preceding claims when made of a moulded plastics material.

13. A device as claimed in claim 13 when made of 50% glass filled nylon or ABS.

14. A device as claimed in any one of claims 2 to 13, wherein a membrane wall is provided to separate the screwdriver-receiving depression in the head portion and the void within the body portion formed by the at least one slot, which membrane wall is readily pierced by a fastener introduced to the device.

15. A device as claimed in any one of claims 2 to 14 wherein the screwdriver-receiving depression in the head portion is adapted to receive the head of a Posidrive type screwdriver of a size usable to pre-form the hole in the sheet material.

16. A method of securing a fastener in friable sheet material comprising the steps of forming an aperture in said sheet material with a screwdriver, bradawl or the like, introducing to the aperture the said other end of a device as claimed in any one of claims 1 to 15, driving the device into the aperture with a screwdriver to securely fix the device in the friable material, and then introducing a fastener into the device and driving it with a screwdriver to pass along the length of the device and past said other end thereof.

17. A method of making a device as claimed in Claim 3 and any one of claims 4 to 14 from a mouldable plastics material, including the use of a two-part mould each part of which has a replaceable blade for forming one half of the slot in the device.

18. A device for securing a fastener in friable sheet material as claimed in Claim 1 and substantially as herein described with reference to Figures 1 to 3 of the accompanying drawings.

19. A device for securing a fastener in friable sheet material as claimed in Claim 1 and substantially as herein described with reference to Figures 1 to 3 of the accompanying drawings.

20. A device for securing a fastener in friable sheet material as claimed in Claim 1 and substantially as herein described with reference to Figure 4 of the accompanying drawings.

21. A method of securing a fastener in friable sheet material as claimed in Claim 15 and substantially as herein described.