GB2114699A - Fastening devices - Google Patents

Abstract

This invention relates to fastening devices for connecting two elements together to initially allow limited adjustment and for subsequently positively locating the element in a selected position. The device 10 comprises a guideway 11 and a punch washer 12. The guideway is formed to connect in a slot 13 in one element 14 and is itself slotted at 15 so that a bolt 16 can pass through. Once the elements are correctly positioned the bolt 16 is tightened causing actual movement of the punch washer 12 into the guideway 11, so that the washer 12 deforms a length of guideway and hence becomes locked in that position by the undeformed portions 19 of the guideway. <IMAGE>

Description

SPECIFICATION Fastening Devices This invention relates to fastening devices for connecting two elements together to allow limited adjustment and for positively locking the elements in a selected position and to punch elements for use in such devices.

When assembling two elements it is often desirable to allow initial adjustment between the elements and then to lock them together once a desired position has been reached or another assembly step has been completed. Typically this is achieved by passing a bolt through the elements, at least one of which is slotted to allow adjustment movement, and then tightening the bolt once the desired position is found. The engagement provided is thus frictional and nonpositive and as a result, particularly under load, the elements often move relative to one another.

It is an object of the invention to provide an improved fastening device and/or a punch element for such a device.

From one aspect the invention consists in a fastening device for connecting two elements together to allow limited adjustment and for positively locating the elements in a selected position comprising, a fastening member securable to one element, a punch element connectible to the member and a deformable part formed or mountable on the other element, the punch and the deformable part being formed so that movement of the fastening member in a sense to draw the elements together causes the punch to deformably engage the deformable part to prevent adjustment movement of the fastening member.

Preferably the deformable part is constituted by a guideway which defines the path of adjustment movement of the fastening member. In this case the punch is shorter than the guideway, when measured along the path of movement, so that the undeformed portions of the guideway serve to hold the punch washer.

The punch may be provided with a projection for engaging and deforming a wall, edge or lip of the part. The projection may be generally wedge shaped. In a preferred embodiment the punch comprises a rectangular base having a pair of dependent parallel walls and a pair of wedge shaped projections inclined in opposite senses one to the other. The adjacent pairs of projections and walls may define a groove between them or alternatively each projection may be formed intergrally with a respective wall. The punch may be in the form of a washer or a nut or it may be integral with the fastening member.

The deformable part may comprise a pair of generally upstanding walls, at least one of which may have an inturned lip extending along its free edge. The part may further comprise a slotted base.

From a second aspect the invention consists in an assembly of elements connected together by a fastening device as defined hereinbefore, in which case the deformable part may be plunge fitted in a slot in the other element. Alternatively the deformable part may be formed integrally with the other element.

From a third aspect the invention consists in a locking punch element comprising a base connectible to a fastening member and a projection extending from the base to provide a bearing surface to allow the washer to be slid on a race or guideway in a first direction and for deforming a portion of the race or guideway when moved towards the race or guideway in a second direction.

Preferably the projection is wedge shaped, in which case it may be inclined at an angle, to the base, lying in the range 250 to 750.

Conveniently the angle may be 50 .

The element may further comprise a pair of dependent generally parallel walls and having a pair of wedge shaped projections, inclined in opposite senses, one to the other. The adjacent pairs of projections and walls may define a groove between them or alternatively each projection may be formed integrally with a respective wall.

The base may be in the form of a washer.

The invention may be performed in various ways, specific embodiments of which will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is an end view of the components of a fastening device; Figure 2 is a view from above of two elements connected by the fastening device of Figure 1 and a fastening member; Figure 3 is a section along the line Ill-Ill in Figure 2; Figure 4 is a section along the line IV--IV in Figure 2; and Figure 5 is a scrap cross-sectional view of an alternative construction of a fastening device.

As is shown in the drawings a fastening device, generally indicated at 10 comprises a channel shaped guideway 11 and a punch washer 12. The guideway is formed to connect in a slot 13 in one element 14 and is itself slotted at 1 5 so that a bolt 1 6 can pass through it to engage in a threaded aperture 17 in another element 18.

The punch washer 12 is slipped onto the bolt 1 6 prior to its insertion in the aperture 1 7 such that the washer rests on the guideway 11. In this position the elements 14 and 18 are movable along the path defined by the slots 1 3 and 1 5 so that adjustments in the relative positions of the elements can take place. Once a desired position is reached the bolt 1 6 is tightened causing axial movement of the punch washer 12 into the guideway 1 so that the washer 1 2 deforms a length of the guideway and hence becomes locked in that position by the undeformed portions 1 9 of the guideway.

As can be seen in Figures 1 and 2 the punch washer 12 comprises a base 20, which has a central aperture 21 for the bolt 16, dependent walls 22 extending along a pair of opposite edges of the base 20 and wedge-shaped projections 24 on respective sides of the aperture 22.

The wedge-shaped projections 24 are inclined in opposite senses so that they diverge as they approach the base 20. Each projection 24 defines a groove 25 with its adjacent wall 22.

The channel shaped guideway has a slotted base 26 and a pair of upstanding parallel walls 27.

Each wall has an inwardly pointing lip 28 extending along its upper edge. The slot 1 5 in the base 26 is slightly shorter than the slot 13 in the element 14 so that the guideway can be plunge fitted into the slot 13, as shown in figure 4.

The grooves 25 are so dimensioned that they slidingly receive the lips 28, when the elements are loosely assembled for adjustment. The punch washer 12 therefore can slide up and down the guideway 11 during adjustment. When the desired position is reached and the bolt 1 6 is tightened the punch washer 12 is pushed downwardly against the lips 28 and the projections deform those portions of the lips, which they engage forcing them back against the walls 27. As the punch washer 12 is much shorter than the guideway 11, in the direction of movement, an undeformed portion 1 9 of the guideway lilies on either side of the punch washer 12; the ends of these portions 1 9 serving to lock the washer, and hence the bolt, against further adjustment movement. This can be clearly seen in Figure 4.

It will be appreciated that the punch washer 12 could be formed integrally with the bolt 16 and that it need not completely surround the bolt, but merely be formed so that once held by the undeformed portions, it will not allow further adjustment movement of the bolt 1 6. It will also be appreciated that the guideway 11 can be formed integrally with the element 14.

Indeed it is not essential for the deformable section of the device 10 to constitute a guideway, and it could be constituted, for example by a single deformable rib running parallel to the slot 15.

In some instances it may be desirable to provide adjustment in more than a single direction, for example the slot 13 could be curved or cruciform.

Other portions of the guideway may be deformed, for example the bolt could be tapered so as to cause sideways movement of the punch, as it was tightened, in which case the punch may be formed to laterally deform the walls 27.

Figure 5 shows an alternative construction of the punch washer 12, in which the projections 24 are formed integrally with the walls 22. In this case the projections could act on the outside of walls 27 forcing them downwardly and inwardly as shown in chain line, as the bolt 1 6 was tightened.

Any suitable fastening member may be used, for instance a nail. Similarly the punch washer 12 and guideway 11 can be made of any suitable material, e.g. steel, aluminium, bronze, brass, nylon etc. Normally it is convenient to use the same material for each component, but in the case of where the guideway is made of nylon it may be preferable to have a metal punch washer.

Claims (26)

1. A fastening device for connecting two elements together to allow limited adjustment and for positively locating the elements in a selected position comprising, a fastening member securable to one element, a punch element connectable to the member and a deformable part formed or mountable on the other element, the punch and the deformable part being formed so that movement of the fastening member in a sense to draw the elements together causes the punch to deformably engage the deformable part to prevent adjustment movement of the fastening member.

2. A device as claimed in claim 1, wherein the deformable part is constituted by a guideway which defines the path of adjustment movement of the fastening member.

3. A device as claimed in claim 2, wherein the punch is shorter than the guideway, when measured along the path of movement, so that the undeformed portions of the guideway serve to hold the punch.

4. A device as claimed in any one of the preceding claims, wherein the punch is provided with a projection for engaging and deforming a wall, edge or lip of the part.

5. A device as claimed in claim 4, wherein the projection is generally wedge shaped.

6. A device as claimed in any one of the preceding claims, wherein the punch comprises a rectangular base having a pair of dependent parallel walls and a pair of wedge shaped projections inclined in opposite senses one to the other.

7. A device as claimed in claim 6, wherein adjacent pairs of projections and walls define a groove between them.

8. A device as claimed in claim 6, wherein each projection is formed integrally with a respective wall.

9. A device as claimed in any one of the preceding claims, wherein the part comprises a pair of generally parallel upstanding walls.

1 0. A device as claimed in claim 9, wherein at least one of the walls has an inturned lip extending along its free edge.

11. A device as claimed in claim 9 or claim 10, wherein the part further comprises a slotted base.

12. A device as claimed in any one of the preceding claims wherein the punch is in the form of a washer or a nut.

13. A device as claimed in any one of claims 1 to 9 wherein the punch is integral with the fastening member.

14. An assembly of elements connected together by a fastening device as claimed in any one of the preceding claims.

1 5. An assembly as claimed in claim 14, wherein the part is plunge fitted in a slot in the other element.

16. An assembly as claimed in claim 1 5, wherein the part is formed integrally with the other element.

1 7. A locking punch element comprising a base connectible to a fastening member and a projection extending from the base to provide a bearing surface to allow the base to be slid on a race or guideway in a first direction and for deforming a portion of the race or guideway when moved towards the race or guideway in a second direction.

18. An element as claimed in claim 17, in which the projection is wedge shaped.

1 9. An element as claimed in claim 18, wherein the projection is inclined at an angle, to the base, lying in the range 25C to 750.

20. An element as claimed in claim 19, wherein the projection is inclined at an angle of 50 .

21. An element as claimed in any one of the preceding claims, further comprising a pair of dependent generally parallel walls and having a pair of wedge-shaped projections, inclined in opposite senses one to the other.

22. An element as claimed in claim 21, wherein adjacent pairs of projections and walls define a groove between them.

23. An element as claimed in claim 21,wherein each projection is formed integrally with a respective wall.

24. An element as claimed in any one of claims 17 to 23 wherein the base is in the form of a washer.

25. A fastening device for locking two elements together substantially as hereinbefore described with reference to the accompanying drawings.

26. A locking punch element substantially as hereinbefore described with reference to the accompanying drawings.