GB2080473A - Slide fastener - Google Patents

Abstract

A fastener for securing an enclosure to a wall or other upright surface comprises an elongate member, formed with a keyhole slot consisting of a generally circular aperture 9 with a narrower parallel- sided extension 10 leading from the aperture 9 and, on opposite sides of the extension 10, a pair of ramp surfaces 28 starting at the edge of the aperture 9 for engagement beneath the head of a supporting screw 26 projecting through the aperture 9. The member also includes a threaded socket 13, 15 at the end closer to the aperture for the receipt of a screw 16 for moving the member lengthwise and, towards the end remote from the threaded socket 13, 15, a longitudinal slot 18 for the passage of a guide screw 20. Tightening of the screw 16 pulls the member 8 to the right and causes the ramp surfaces 28 to engage beneath the counter-sunk head of the screw 26 so as to produce a wedging action which presses the whole assembly against the wall 3. <IMAGE>

Description

SPECIFICATION Slide fastener This invention relates to the fastening in position to a wall or other upright surface of a boxlike enclosure and is particularly concerned with the fastening of such enclosures when there is no access available for fastening purposes through the enclosure itself, i.e. when the enclosure has a closed front.

The great majority of enclosures, such as hanging cabinets, have a front which opens and there is then no problem in securing these to a wall surface. For this purpose, the back of the enclosure is commonly formed with keyhole slots, i.e. slots comprising a generally circular aperture with a narrower, parallel sided extension leading from the aperture. Screws are screwed into the wall with their heads proud of the wall surface and the enclosure is then moved into position so that the heads of the screws pass through the circular apertures of the respective slots, after which the enclosure is moved downwardly so that the screws move into the narrower parts of the respective slots and thereby secure the enclosure to the wall.Although this method of fixing is quite straight forward, it has the disadvantage that the fastening is not totally secure and if the enclosure is knocked it can be displaced. In addition, there is no means of securing satisfactory compression between the enclosure and the wall.

If, however, the front of the enclosure is closed, even this form of fastening is not available and the only practical alternatives are to use long screws extending right through from the face of the enclosure, which disfigure the face or, alternatively, to use ear-pieces or similar lugs or brackets, extending laterally from the rear surface of the enclosure, which are equally unsightly.

According to the present invention, a fastener which is particularly useful in the circumstances just described comprises an elongate member formed with a keyhole slot of which the parallelsided extension leads along the length of the member from the aperture and, on opposite sides of the extension, a pair of ramp surfaces starting at the edge of the circular aperture of the slot for engagement beneath the head of a screw projecting through the aperture, the member also including a threaded socket at the end closer to the aperture for the receipt of a screw for moving the member lengthwise.

In use, two or more such fasteners are fitted close to the rear surface of an enclosure, being inserted during the assembly of the enclosure itself and before the front is closed, and supported by screws extending through holes in respective end surfaces of the enclosure and screwing into the threaded sockets at the ends of the members.

The length of the screws is such that with the end of each screw just engaging its respective socket, the circular aperture of the keyhole slot of each member is in register with a corresponding circular aperture in the rear surface of the enclosure. Accordingly, the enclosure can then be fitted against a wall or other upright surface so that the heads of the supporting screws, previously screwed into the surface at the appropriate locations, can project through the apertures in the rear of the enclosure and also through the apertures in the fastener members.

With the enclosure in this position, the screws engaging the sockets at the ends of the fastener members are tightened, thus pulling the fastener members towards the respective ends of the enclosure and causing the ramp surfaces to engage the heads of the supporting screws as the screws enter the parallel-sided extensions of the respective keyhole slots as a result of the movement of the fastener members. The engagement of the ramp surfaces with the heads of the supporting screws has a wedging action which increases progressively as the pulling screws are tightened and the reaction between the ramp surfaces and the supporting screw heads forces the enclosure firmly against the wall or other surface, thereby holding the enclosure firmly in position and producing any required degree of compression depending on the extent to which the screws are tightened.

Although, as mentioned initially, such a form of fastener is primarily useful with an enclosure having no front access, it can also be used with advantage in connection with open-fronted enclosures since it produces a compressive force which presses the enclosure against the wall surface in a way which is not obtainable with a normal keyhole slot.

If the enclosure is open-fronted, the operation of the fastener as just described can be observed and, if necessary, the fastener can be steadied by hand while the pulling screw is being tightened. If there is no front access, however, the fastener is inaccessible and since it is important that it should be capable of sliding smoothly in the direction in which it is being pulled by the tightening screw, each fastener member preferably includes a longitudinal slot for the passage of a guide screw, this being located towards the end remote from the threaded socket. Accordingly, when the fastener is being initially fitted in position, i.e.

during the assembly of the enclosure, a guide screw can be inserted through the slot and screwed into the rear of the enclosure so that the member is supported at one end by the pulling screw engaging the threaded socket and towards the other end by the guide screw passing through the longitudinal slot so that when the former screw is tightened up, the fastener member moves along a parth determined by the guide slot and the ramp surfaces move beneath the head of the supporting screw with certainty.

An example of a fastener in accordance with the invention and its mode of use will now be described in more detail with reference to the accompanying drawings, in which: Figure 1 is a sectional plan view through an enclosure to be fixed in position and also partially through the fastener member, the components being shown immediately after fitting over a fastening screw; Figure 2 is a corresponding sectional view of part of Figure 1 but showing the position of the components when the fastener has been moved to its operative position; and Figure 3 is a view of the same parts as in Figures 1 and 2 as seen through a portion cut away in the rear of the enclosure.

The enclosure illustrated as 1 is, in this particular example, a ventilating device which includes a permanent vent 2 for connection to a duct (not shown) which extends through a wall 3 to which the enclosure 1 needs to be fastened. As can be seen, the enclosure is closed at the front so that there is no front access for fixing purposes.

Enclosures of this same general type are used for a variety of purposes including ventilation and air conditioning. A gasket 4 is mounted between the rear of the enclosure 1 and the surface of the wall 3 and compression of this gasket is important in order to prevent the ingress of noise into the room where the enclosure is fitted. In order to comply with these various requirements, the enclosure is held in position by a number of fasteners, one of which is indicated generally as 6 in the drawings.

As best seen in Figure 3, the fastener 6 comprises an elongate member 8 formed with a keyhole slot consisting of a generally circular aperture 9 and a narrower, parallel-sided extension 10 leading from the aperture along the length of the member 8. The member 8 includes a base 12 formed with an upstanding end member 13 which is reinforced by sloping side members 14. The end 13 is provided on each side with a metal plate 15, these two plates together forming a threaded socket for the reception of a pulling screw 1 6 which, prior to assembly, is passed through a hole in the end wall of the enclosure 1.

The base 12 also includes a longitudinal guide slot 18 and, during the initial assembly, i.e. before the enclosure 1 is closed, a screw 20 is passed through a hole in the rear wall of the enclosure 1, through the slot 18 and into a nut-like retaining member 22 which, as seen in Figure 3, is wider than the slot 1 8 and maintains the alignment of the fastener even if the screw 1 6 is removed. The gastener 6 is thus supported within the enclosure 1 by the screws 1 6 and 20 and when the screw 1 6 is tightened from the outside of the enclosure, the fastener 6 is pulled to the right, being guided by relative movement between the screw 10 and the slot 18.

The rear face of the enclosure 1 is formed with an opening 24 of approximately the same size as the aperture 9 forming part of the keyhole slot.

Prior to fastening the enclosure 1 to the wall surface 3, a supporting screw 26 is screwed into the wail 3 at a position corresponding to each of the openings 24. Generaliy speaking, two such screws are sufficient, located towards diagonally opposite corners of the enclosure 1. Each screw 26 is screwed home until its head is proud of the wall surface 3 by a distance approximately equal to the thickness of the base 12. Consequently, when the enclosure 1 is fitted in position, the heads of the screws 26 project through the openings 24 and the apertures 9 so that the narrowest part of each counter-sunk head is approximately level with the surface of the base 1 2 of each fastener 6.

In addition to the components already described, the base 12 of each fastener 6 is formed with a pair of wedge-like ramp surfaces 28 g extending immediately alongside the extension 10 and joined by a semi-circular portion 29 for strength. The right hand ends of the ramp surfaces extend down to the level of the surface of the base 12 and when the enclosure 1 is first fitted in position these ends lie immediately beneath the counter-sunk head of the screw 26 Figure 1 shows the starting position immediately after the enclosure 1 has been fitted over the heads of the screws 26 and Figure 2 shows the subsequent position when the pulling screw 1 6 has been tightened to draw the fastener 6 to the right so that the aperture 9 forming part of the keyhole slot moves out of register with the opening 24 and the screw 26 effectively moves into the extension 10 as shown by the dotted line position 26' in Figure 3. This movement to the right causes the ramp surfaces 28 to engage beneath the countersunk head 26 and thus to have a wedging action which presses the fastener 6 and hence the enclosure 1 as a whole firmly towards the wall surface 3, thus compressing the gasket 4 and holding the assembly as a whole firmly in position.

As previously described, the fasteners 6 are fitted in position during the assembly of the enclosure 1, i.e. before the front is closed and once assembly is complete, the only access to each fastener is by way of the pulling screw 16 at the end of the enclosure. The heads of the screws 1 6 are quite unobtrusive and have a minimal disfiguring effect as compared with long screws extending right through the front of the enclosure or laterally extending brackets or lugs. As already explained, a fastener in accordance with the invention is of primary utility when there is no front access to the enclosure, but even when there is front access, the fastener has the advantage of providing compression e.g. to a gasket such as that shown at 4, which is not obtainable by means of a normal keyhole slot connection. Because of the mechanical advantage of the wedging action greater compression can be obtained than by turning a screw in directly with a screwdriver.

Such fasteners are also useful even when the enclosure is not totally enclosed on all sides, e.g.

such fittings as cooker hoods which normally require either unsightly laterally projecting lugs or fastening holes inside the hood which are difficult to locate and difficult to obtain access to.

Claims (4)

1. A fastener for securing an enclosure to a wall or other upright surface and comprising an elongate member formed with a keyhole slot consisting of a generally circular aperture with a narrower parallel-sided extension leading along the length of the member, from the aperture and, on opposite sides of the extension, a pair of ramp surfaces starting at the edge of the aperture for engagement beneath the head of a screw projecting through the aperture, the member also including a threaded socket at the end closer to the aperture for the receipt of a screw for moving the member lengthwise.

2. A fastener according to claim 1 and also including a longitudinal slot for the passage of a guide screw, towards the end remote from the threaded socket.

3. An enclosure for securing to a wall or other upright surface and fitted with a fastener according to claim 1 or claim 2, the threaded socket receiving a screw or bolt inserted through a hole in an end surface of the enclosure and the aperture registering, in one longitudinal position of the fastener with a similar sized aperture in the back of the enclosure.

4. A fastener for securing an enclosure to a wall or other upright surface substantially as described and as illustrated with reference to the accompanying drawings.