A FIXING DEVICE

Abstract: The fixing device serves to connect together a structural part (10) to a rod-shaped element (1). It comprises a split collar (3) engageable into a peripheral circular groove (11) on the element (1), and fixing means (4) for forcing the collar (3) and the structural part (10) away from each other. In this way the portion of the collar (3) which is inside the groove (11) is pressed against a lateral surface (5) of the groove (11) and the structural part (10) against the rod-shaped element (1) or a member carried thereby, so that both the structural part (10) and the split collar (3) are firmly retained on the rod-shaped element (1).

Description: A FIXING DEVICE The invention relates to a device for fixing a structural part to a rod-shaped element, particularly for firm attachment to a rotatable shaft of a structural part intended to rotate with the shaft. A number of devices for such an attachment are known, each of these devices having some disadvantages, known to persons skilled in the art, which make it unsuitable for some applications. The aim of the invention is to provide a device which has some advantages compared with'known attachment devices. The invention provides a device for fixing a structural part to a rod-shaped element, the device comprising a split collar, engageable into a peripheral circular groove on the element, and fixing means for forcing the collar and the structural part away from each other, whereby the portion of the collar which is inside the groove is pressed against a lateral surface of the groove. A device according to the invention has various advantages, including the following: (a) A hexagon key, screwdriver or a small spanner can be used for attachment of a structural part by means of the device instead of e.g. a special big spanner needed for tightening a large nut at the end of a shaft. (b) Corrosion problems are largely eliminated because the device enables the designer to choose suitable clearances for the structural parts to be fixed. (c) When the screws are slackened, the split collar falls away. The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is an axial section showing a fan attached to a shaft by a first embodiment of a device according to the invention, Figure 2 is a fragmentary plan to Figure 1, and Figure 7 shows a detail of a second embodiment. Figure 1 shows a shaft 1 having an end of reduced diameter defining a shoulder and axially spaced therefrom a circular peripheral groove 11. The end carries a rolling bearing 9 in contact with the shoulder, a spacer sleeve 12 in contact with the bearing 9 and a fan 10 in contact with the spacer sleeve 12. The fan 10 has a circular base carrying at the periphery of one side thereof a plurality of equally spaced vanes. The central part of the circular base is thickened and provided with a central hole by which it is slid on to the shaft end and the side carrying the vanes is provided with a circular recess coaxial with the hole. The device has a thrust collar 2 which is provided with a central hole 8 by which it is slid on to the shaft end and has on the face remote from the fan base a circular recess which is coaxial with the hole 8 and defines a circular peripheral wall. The non-recessed face of the thrust collar 2 is received in the recess of the fan base. Figures 1 and 2 further show a split collar 3 composed of two separate halves each having two threaded holes therethrough, each hole receiving a screw 4. In the illustrated embodiment each of the threaded holes in each of the halves of the split collar 3 is spaced about 300 from the respective end of that collar half. In the illustrated working position the split collar 3 is inserted in the groove 11 and the screws 4 are screwed so far as to enter the recess in the thrust collar 2 and press, when tightened, the split collar 3 against the lateral surface 5 of the groove 11 remote from the thrust collar 2. The radial distances of the threaded holes in the split collar 3 from the axis of the collar 3, and the radial distance of the peripheral wall from the axis of the thrust collar 2 are such that the bolts 4 engage the inner surface 6 of the said peripheral wall with a small interference. Assembly is accomplished by first putting on to the shaft the components to be fitted, i.e. the bearing 9, the spacer sleeve 12 and the fan 10, followed by the thrust collar 2 received in the recess in the fan 10 and facing with its recessed side out. The two halves of the split collar 3 are then fitted separately to enter the groove 11 and the screws 4 are tightened to bear against the bottom of the recess in the thrust collar 2. The split collar 3 is prevented from falling out since the screws 4 push at 7 against the bottom of the recess in the thrust collar 2 and engage the inner surface 6 of the peripheral wall of the thrust collar 2. As the screws 4 are further tightened the split collar 3 is pushed hard against said lateral surface 5 of the groove 11, so that no further pressure or centrifugal force can displace it. Simultaneously the fan 10 is pressed on to the spacer sleeve 12 supported, via the bearing 9 on the shoulder of the shaft 1 and thereby firmly held on the shaft end. It will be appreciated that many modifications could be made within the scope of the appended claims. So for instance the circular base of the fan 10 could be without a circular recess for the thrust collar 2, or the thrust collar 2 could be entirely dispensed with and the screws 4 can contact the circular base of the fan 10 directly, which base may or need not be provided with a circular or annular groove or other recesses or circular or annular groove or other recesses or depressions for the screws 4. Also the spacer sleeve 12 can be dispensed with and the circular base of the fan 10 made to incorporate a portion having a function similar to that of the spacer sleeve 12. Also the bearing 9 could be dispensed with and the shaft could have a bearing situated elsewhere. While the collar 3 is shown in the form of two separate semi-annular elements, because that embodiment has certain advantages, the invention is not limited to that embodiment, and may be composed of similar halfannular elements connected e.g. at one of their ends to each other by suitable means, such as a hinge, facilitating insertion of the collar 3 into the groove 11. The collar 3 could also be formed by more part-annular parts than two, which could either be independent of each other or either all of them or at least some of them could be connected in a suitable manner, e.g. by resilient means, to facilitate insertion of the collar 3 into and its removal from the groove 11. Instead of making threaded holes in the split collar 3, threaded holes may be made in the thrust collar 2 (Figure 3), which then is not recessed, or, if the thrust collar 2 is dispensed with, the threaded holes may be made directly in the circular base of the fan 10 which then is not recessed. In that case smooth holes are made in the split collar 3 and instead of the screws 4 fixing elements are used which have a smooth portion 41, which may have on top a screwdriver slot or a recess for an Allen wrench, a collar 42, which may be either circular or hexagonal, and a threaded portion 43 screwed into the threaded hole in the collar 2 or the circular base of the fan 10. By unscrewing the threaded element from the threaded hole the collar 42 engages the adjacent face of the split collar 3, and the split collar 3 and the structural part 10 are forced away from each other whereby the portion of the collar 3 which is inside the groove 11 is pressed against the lateral surface 5 of the groove 11. Instead of the collar 42 the threaded element may have a shoulder serving the same purpose.

Claims: CLAIMS 1. A device for fixing a structural part to a rodshaped element, characterized in that it comprises a split collar (3) engageable into a peripheral circular groove (11) on the element (1), and fixing means (4) for forcing the collar (3) and the structural part (10) away from each other, whereby the portion of the collar (3) which is inside the groove (11) is pressed against a lateral surface (5) of the groove (11). 2. A device according to Claim 1, characterized in that the fixing means are threaded elements (4) engageable in threaded holes. 3. A device according to Claim 2, characterized in that the threaded holes are in the collar (3), and the threaded elements are screws (4) which pass through the threaded holes and which, on being screwed through the holes, press directly or indirectly on to the structural part (10) being attached to the element (1) thereby forcing the collar (3) away from the structural part (10). 4. A device according to Claim 3, characterized in that, in operation, the screws (4) press on to the structural part (10) via thrust means (2) positioned between the structural part (10) and the split collar (3). 5. A device according to Claim 3 or 4, characterized in that the structural part (10) or the thrust means (2) define a peripheral circular wall the inner surface (b) of which is engaged by the screws (4). 6. A device according to Claim 2, characterized in that the threaded holes are in the structural part (10) or in a thrust means (2) positioned between the structural part (10) and the collar (3). 7. A device according to any one of the preceding claims wherein the split collar (3) is formed by two or more part-annular elements. 8. A device according to Claim 7, characterized in that the two elements, or at least two of the elements, forming the collar (3) are connected to each other.

Inventors: FISHER, DUDLEY JOHN
Applicants: HAMMOND ENGINEERING LIMITED
Application year: 1982
Main classification: F16B21
IPC codes: F16B21