GB2160610A

GB2160610A - Fixing devices

Info

Publication number: GB2160610A
Application number: GB08503063A
Authority: GB
Inventors: Jose Francisco Mut
Original assignee: Decoletaje & Extrusion SA
Current assignee: Decoletaje & Extrusion SA
Priority date: 1984-06-22
Filing date: 1985-02-07
Publication date: 1985-12-24
Also published as: GB8503063D0; FR2566479A1; FR2566479B1; GB2160610B; BE901655A; DE3503450A1

Abstract

A fixing device which can be anchored in a bore 7 prepared in in situ concrete comprises a threaded bolt (1,2,3) carrying a cylindrical separator (4), an expandible sleeve (5) and a conical nut (6). The separator (4) presents a peripheral cylidrical rebate (11) to a number of resilient longitudinal blades (12) formed on the opposing end of the sleeve (5) and defined by longitudinal grooves or slots in the sleeve and forming a conical structure opening outwardly from the sleeve. The rebate is able to receive these blades during introduction of the threaded member carrying the anchoring assembly into a bore (7), the blades serving by their own elasticity to fix the anchoring assembly within the bore, hindering turning of the sleeve and adapting to irregularities in the wall of the bore. The nut (6) is prevented from rotating by its lugs (17) which engage in the losts (14) in the expandible sleeve (5). <IMAGE>

Description

SPECIFICATION Fixing devices This invention relates to fixing devices. It is particularly concerned with fixing devices which can be used for fixing various elements, such as machinery or pieces of diverse structure, in concrete masses that are already in situ. Such fixing devices normally incorporate expandible elements in order to produce a radial force against a bore made to receive the device, thereby to achieve desired anchoring of the device. The dispositions of the expandible elements are varied, always with the intention of taking advantage of the effect of rotation of the device after it has been introduced into a bore and utilising screw-threading of the device in order to get the effect of expansion of the expandible elements coupled to the device.

According to the present invention there is provided a fixing device comprising a threaded member and an anchoring assembly carried by the threaded member and including a cylindrical separator, and expandible sleeve and a conical nut; there being a coupling zone between the cylindrical separator and the expandible sleeve in which zone the separator presents a peripheral cylindrical rebate to the opposing end of the sleeve, the sleeve at this end presenting to the rebate a plurality of longitudinal blades defined by longitudinal grooves in the sleeve and forming a conical structure opening outwardly from the sleeve, the rebate being able to receive the blades during introduction of the threaded member carrying the anchoring assembly into a bore, and the blades serving by their own elasticity to fix the anchoring assembly within the bore, hindering turning of the sleeve and adapting to irregularities in the wall of the bore when expanding into engagement with this wall. In use the anchoring effect obtained with this fixing device is facilitated without requring additional components such as pieces of plastics materials, as is the case in some known fixing devices, and the initial fit of the device in the bore in which it is to be secured is facilitated.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figures 1 and 3 are longitudinal sectional views of a bolt shown, in Fig. 1 entered into a bore and, in Fig. 3, made fast in the bore; Figure 2 is a side view of the inner end portion of the bolt as shown as shown in Fig.

1; Figure 4 is a sectional view on a larger scale of an intermediate portion of the bolt of Figs. 1 and 3; Figures 5 and 6 are sectional views respectively taken on lines V-V and VI-VI in Fig. 4; Figure 7 is a sectional view on the same scale as Fig. 4 of the inner end portion of the bolt of Figs. 1 and 3; Figures 8 and 9 are sectional views respectively taken on lines VIII-VIII and IX-IX in Fig. 7; Figure 10 is a sectional view on a still larger scale of a detail of the inner end portion of the bolt; and Figure 11 is cross-sectional view of the detail of Fig. 10.

The bolt which is shown in the drawings is a fixing device for fixing various elements, such as items of machinery, in concrete masses that are already in situ. The bolt has a body 1 having a hexagonal head 2 at one end and a screw-threaded zone 3 at the other end.

The screw-threaded zone 3 receives externally an expandible anchoring assembly which is formed, in the direction from the bolt head 1, by a cylindrical separator 4, an expandible sleeve 5 and a conical nut 6. Between the bolt head 1 and the separator 4 there is a washer 10.

In order to secure an item 8 which can be, for example, a piece of machinery or a struc tural element, to, for example, a concrete block 9 or a smelting base, or similar, the bolt carrying the anchoring assembly 4/5/6 and the washer 10 is passed through a hole in the item 8 and into a prepared bore 7 in the otherwise solid block 9. This is the position shown in Fig. 1.

The separator 4 has at its end remote from the bolt head 2, in a coupling zone between the separator 4 and the sleeve 5 where the separator 4 is engaged with the expandible sleeve 5, a peripheral rebate 11 in which are received twelve (in the illustrated example) blades 1 2 extending longitudinally from the expandible sleeve 5 so as to be presented to the rebate 11. These blades 12, which are defined by longitudinal grooves in the sleeve 5, are spalyed outwardly to form a conical structure for engaging the wall of the bore 7 to effect an immobilizing action on the sleeve 5. The greater diameter of the crown that is defined by this conical structure is larger than the greatest diameter of the remainder of the anchoring assembly 4/5/6.

The expandible sleeve 5 has four (in the illustrated example) wings 15, separated from one another by grooves 1 4. The wings 1 5 are longitudinal of the sleeve 5, are of greater length than the blades 12, and extend over the major part of the length of the expandible sleeve. These wings 1 5 splay outwardly so as to be open from the sleeve 5 at the end of the sleeve 5 remote from the blades 12, the wings 1 5 being positively deformed to splay outwardly by action of the nut 6. At the outer end of each wing 1 5 there is a milled zone 1 6 which serves to increase the coefficient of friction with respect to the wall of the bore 7, thus improving anchoring.

The conical nut 6 which is screwed onto the screw-threaded zone 3 of the bolt has radially projecting lugs 1 7 (there are two in the illustrated example) at its extremity of smaller diameter. Each of these lugs is engaged in a corresponding one of the grooves 14.

When the bolt complete with the anchoring assembly 4/5/6 is inserted in a bore of suitable diameter, first the engagement of the blades 12 with the wall of the bore, and then the engagement of the milled zones 1 6 with the wall of the bore, prevents the expandible sleeve 5 rotating. As a result, due to the engagement of the lugs 1 7 in the grooves 14, rotation of the bolt under these conditions results in axial advance of the nut 6 in the direction towards the sleeve 15, and axial advance of the bolt in the opposite direction.

Co-operation between conical inner surfaces 1 8 at the outer ends of the wings 15, and the conical outer surface 1 9 of the conical nut 6 results in a progressive jamming action of the nut against the expandible sleeve and, therefore, in radial expansion of the wings 1 5 which are between the grooves 14 so that the wings are driven against the wall of the bore.

Once the sleeve 5 is firmly anchored in the bore, further rotation of the bolt serves to secure the item 8 hard against the face of the block 9.

To sum up, once the bolt complete with its anchoring assembly has been introduced into the bore, there is obtained immediately a first retaining action, by the blades 1 2. Subsequently this action is complemented by strong radial holding action effected by screwing the bolt, and resulting from the effect of the nut 6 on the conical end of the expandible sleeve 5 the nut being constrained to translate and not rotate by the engagement of the radial lugs 1 7 in the grooves 14. The combination of these two actions ensures the efficiency of the rotation of the bolt and the effective expansion of the its associated elements.It is to be noted that the cylindrical separator 4 establishes contact at one of its extremities with the washer 10 under the bolt head, and its other extremity establishes contact with the expandible sleeve 5, which in its turn is coupled to the conical nut 6 which is screwed onto the screw-threaded zone 3 of the bolt.

The provision of the rebate 11 in the cylindrical separator 4 where it is coupled with the expandible sleeve 5, since this rebate can receive the expandible blades 1 2 at the adjacent extremity of the sleeve 5 as the bolt and its anchoring assembly is introduced into a bore, facilitates the introduction of the bolt and its anchoring assembly into the bore and adaptation to any irregularities in the wall of the bore, these blades 12 serving by their own elasticity to lock the sleeve 5 in the bore so that the sleeve 5 does not rotate during subsequent rotation of the bolt in screwing operation to tighten the bolt in the bore.The longitudinal grooves 14 which run along the major part of the length of the expandible sleeve 5, these grooves being open at the extremity of the sleeve remote from the blades 12, and the radial connecting lugs 1 7 of the nut 6 which are engaged in these grooves, constitute a rectilineal guide system for the nut 6.

Thus it is the case that the blades 1 2 of the expandible sleeve 5 exercise an anchoring action in the bore, which impedes egress of the bolt and its anchoring assembly and simply acts by proper elastic action of these blades, which are slightly deformed towards the exterior. In addition, the radial lugs in the conical nut, engaged in the longitudinal grooves of the expandible sleeve, ensure that screw-threaded rotation of the bolt in the nut results in rectilineal motion between the nut and the bolt with the nut tending to move in the opposite linear direction to the bolt when the bolt is tightened. As the nut cannot turn due to the interaction of its radial lugs with the longitudinal grooves there is ensured that expansion of the wings 1 5 takes place to produce a further strong jamming action progressively applied to the wall of the bore in which it is desired to introduce and anchor the bolt.

To indicate the thickness of the items 8 which can be satisfactorily fixed by the bolt, the separator 4 has a peripheral groove 1 3 whose function is simply to mark the maximum thickness of the item 8 which can be accommodated.

In place of the bolt 1 which is screwthreaded at one end only as illustrated in Figs.

1 and 3 there can be utilised a stud that is screw-threaded at both its extremities (or over its entire length) with a nut replacing the bolt head 2 illustrated.

Claims

1. A fixing device comprising a threaded member and an anchoring assembly carried by the threaded member and including a cylindrical separator, an expandible sleeve and a conical nut; there being a coupling zone between the cylindrical separator and the expandible sleeve in which zone the separator presents a peripheral cylindrical rebate to the opposing end of the sleeve, the sleeve at this end presenting to the rebate a plurality of longitudinal blades defined by longitudinal grooves in the sleeve and forming a conical structure opening outwardly from the sleeve, the rebate being able to receive the blades during introduction of the threaded member carrying the anchoring assembly into a bore, and the blades serving by their own elasticity to fix the anchoring assembly within the bore, hindering turning of the sleeve and adapting to irregularities in the wall of the bore when expanding into engagement with this wall.

2. A fixing device as claimed in Claim 1, wherein the longitudinal blades form a widened crown outwardly of the sleeve, the greater diameter of this crown being larger, prior to introduction of the threaded member and its anchoring assembly into a bore, than the greatest diameter of the remainder of the anchoring assembly.

3. A fixing device as claimed in Claim 1 or 2, wherein radial lugs on the conical nut at the extremity of smaller diameter of the nut are engaged in longitudinal grooves in the expandible sleeve to couple the nut to the sleeve such that, when the sleeve is fixed against turning in a bore, the nut is also held fast against turning so that screwing of the threaded member results in actual displacement of the nut in a contrary sense to actual movement of the threaded member whereby the nut effects expansion of the expandible sleeve with which it co-operates.

4. A fixing device substantially as herebefore described with reference to the accompanying drawings.