Field of the Invention

The present invention relates to the field of thrust collars which are primarily employed to prevent or limit the axial movement of a rotating shaft and/or related bearing arrangement.

Background of the Invention

Thrust collars are used in a wide variety of engineering applications where axial movement of a rotating shaft and/or associated bearing arrangement is to be prevented or at least limited to a large degree. In heavy engineering applications such as in, for example, steel production, thrust collars are used on the end of the steel mill rollers to ensure that there is no axial movement of the rollers or their associated bearings. Were the rollers and/or bearings to move in the axial direction then the precision required from the rollers in order to produce the desired shaping of the steel would be lost. Similarly, axial movement would put greater strain on the bearings themselves, leading to higher wear or indeed failure of the bearings.

Traditionally, thrust collars have been formed from steel and similar metals and the resulting weight of the collar (50-60kg in heavy engineering applications such as steel production) means that there is an increased risk of injury to the personnel who must handle these collars during maintenance work on the production line. Furthermore, these metal collars cause wear on the adjacent parts of the roller, shaft or the like. One solution to this weight issue has been to manufacture the collars from nylon or a similar plastics material. However, whilst these collars are lighter and reduce wear on the roller or shaft they are formed in the same way as metal collars, where two hinged semi-circular rings are bolted together about the shaft on which the collar is being employed. Consequently, the tightening and releasing of the collars also carries the risk of injury, where hands or digits of the personnel may be trapped during the procedure. As well as these risks to personnel, there are also time and cost implications for using these existing metal and plastic collars. Firstly, the clamping and removal procedures are time-consuming given the need to tighten or remove one or more bolts, and there is also the risk of an unskilled operative overtightening the collar bolt(s). In the case of a metal collar this may damage or break the bolt, whilst with a plastic collar such overtightening may damage or break the collar itself.

It is an aim of the present invention to obviate or mitigate one or more of these disadvantages with existing thrust collars.

Summary of the Invention

According to the first aspect of the invention, there is provided a thrust collar comprising:

first and second generally semi-circular body members, each body member having a first end and a second end;

a hinge arrangement pivotably connecting the first ends of the body members to one another; and

a locking mechanism comprising:

a locking member;

a locking rod having a first end pivotably attached to the second end of the first body member, and a second end pivotably attached to the locking member; and

a locking recess located adjacent the second end of the second body member, the locking member being engageable in the locking recess so as to lock the second ends of the first and second body members together.

The locking recess may include a niche and the locking member may include a catch which is biased into the niche when the locking member is located in the recess.

The locking recess may have a proximal end which is concave, and the locking member may have a corresponding proximal end which is shaped so as to match that of the concave proximal end of the locking recess. Consequently, the locking member may rotate relative to the locking rod when the proximal end of the locking member is located in the locking recess, and in addition the locking member cannot be removed from the locking recess by radial movement alone. Instead, the locking member must be rotated and moved radially in order to exit the recess. The niche may be located at a distal end of the recess, with the catch located at a corresponding distal end of the locking member.

The first end of the locking rod and the second end of the first body member may be pivotably attached by a first pivot pin, and the second end of the locking rod and the locking member may be pivotably attached by a second pivot pin, wherein each pivot pin includes a threaded aperture and the locking rod has an external thread, whereby the distance between the first body member and the locking member may be adjusted.

The first and second body members and the locking member may each be formed from the same material. The material may be cast polyamide.

Brief Description of the Drawings

A preferred embodiment of the invention will now be described, by way of example only, with reference to the following drawings:

Figure 1 is a side view of a thrust collar;

Figure 2 is a sectional view of the thrust collar along the line ll-ll shown in Figure 1 ;

Figure 3 is a detail view of a partial cross section marked "III" in Figure 1 ; and

Figure 4 is a perspective view of the thrust collar shown in Figure 1 .

Detailed Description of the Drawings

A preferred embodiment of a thrust collar in accordance with the present invention is shown in Figures 1 -4. The collar 10 comprises first and second generally semicircular body members 12,14 which form the ring-shaped collar when the two body members are brought together. The first body member 12 has first and second ends 16,18 and the second body member 14 also has first and second ends 20,22. The collar 10 includes a hinge arrangement which pivotably connects the first ends 16,20 of the body members 12,14 to one another. Each of the first ends 16,20 of the body members 12,14 is bisected by a hinge slot 19,21 , as best seen in Figures 2 and 4. Each of the first ends 16,20 also includes a hinge aperture 24,26 which extends transversely through its respective body member 12,14 and connects with the hinge slot 19,21 therein. A hinge plate 28 which has first and second hinge plate apertures is located in the hinge slots 19,21 of the body members 12,14 such that its hinge plate apertures align with the hinge apertures 24,26 in the body members. A pair of hinge pins 30,32 are positioned in the apertures and held in place by a pair of external circlips 34 or similar, thus allowing the body members 12,14 to pivot relative to one another about the hinge.

The collar 10 also includes a locking mechanism for closing the collar around a shaft or the like without the need for any additional mechanical fixtures. The locking mechanism has a locking member or handle 40 which is curved in the longitudinal direction so that it will fit flush within a locking recess 42 having a corresponding shape and which is located in the external surface of the second body member 14 adjacent the second end 22 of said body member. A locking rod 44 has a first end 46 which is pivotably attached to the second end 18 of the first body member 12 by a first pivot pin 48, and a second end 50 which is pivotably attached to the locking member 40 by a second pivot pin 52. The locking mechanism is an over centre latch arrangement, where the locking member 40 engages in the locking recess 42 so as to pull the second ends 18,22 of the first and second body members 12,14 together and lock them in place. Optionally, the first and second pivot pins 48,52 may be barrel nuts with threaded internal apertures, and the locking rod 44 may have an external thread so as to engage with the threaded apertures of the barrel nuts such that the distance between the first body member 12 and the locking member 40 may be adjusted so as to vary the clamping force applied by the body members 12,14 when their second ends 18,22 are brought into contact with one another. As best seen in Figure 4, the locking recess 42 has a proximal end 43 which is concave, and the locking member 40 has a corresponding proximal end 47 which is shaped so as to match that of the concave proximal end of the locking recess. This allows the locking member 40 to rotate relative to the locking rod 44 when the proximal end 47 of the locking member is located in the locking recess 42. Furthermore, the locking member 40 cannot be removed from the locking recess 42 by radial movement alone. Instead, the locking member 40 must be rotated about the second pivot pin 52 first and then moved radially in order to exit the recess 42, which ensures that the collar cannot be unlocked inadvertently. To further reduce the chances of inadvertent unlocking of the collar, a safety catch may also be provided, as is shown in Figure 3. A distal end 45 of the locking recess 42 includes a niche 60, and a catch 62 is slidingly engaged in a distal end 49 of the locking member 40. A spring 64 biases the catch 62 into the niche 60 when the locking member 40 is properly located in the recess. The catch 62 includes a guide slot 63, and a guide pin 66 extends transversely across the distal end 49 of the locking member 40 and through the guide slot. The guide slot 63 and guide pin 66 combine to ensure the catch 62 slides in the desired direction and also to limit the movement of the catch under the action of the spring 64.

Industrial Applicability

The main components of the thrust collar - the first and second body members and the locking member - may each be formed from a metal such as, for example, steel. However, in order to make the collar lighter and thus easier for an operative to lift and manipulate it is preferred to form the body members by casting a suitable thermoplastic material such as, for example, a polyamide. A preferred example of a suitable material is a proprietary grade of cast polyamide manufactured and sold by the applicant under the trade name DEVLON T100. Most preferably, the body members and locking member are all formed from the same material. The hinge plate, hinge pins, locking rod, pivot pins, circlips and catch spring are all preferably formed from a suitable metal such as, for example, steel or stainless steel. The hinge plate, hinge pins and pivot pins may alternatively be formed from a suitable plastics material which may be, for example, a synthetic polymer such as nylon. The catch member may be formed from a self-lubricating thermoplastic material, such as, for example, a self-lubricating polyamide material manufactured and sold by the applicant under the trade name DEVLUBE.

The manner in which the collar is used will now be described with reference once again to Figures 1 -4. In this particular example the collar is to be used on the shaft of a steel roller in a steel rolling mill, but it should be understood that the collar is not limited to this specific use.

Prior to being positioned on the shaft, the collar will be open. That is the locking member 40 attached to the first body member 12 will be disengaged from the locking recess 42 in the second body member 14. Consequently, the first and second body members 12,14 may pivot relative to one another on the hinge plate 28 and open up to a sufficient degree to allow the roller shaft to enter between the two body members. The roller shaft typically has a circumferential groove or niche on either end thereof, where the grooves are outboard of the bearings which rotatably support the shaft. A technician will lift the open collar over the shaft and locate it in the groove. Once in position, the free second ends 18,22 of the body members 12,14 are brought towards one another by the technician as the body members now pivot inwardly towards one another on the hinge plate 28. Once the second ends 18,22 are relatively close to one another, the technician will take the locking member 40 and pull it over towards the locking recess 42. In order for the proximal end 47 of the locking member 40 to enter the proximal end 43 of the recess 42 the locking member must be pivoted about the second pivot pin 52 such that it is generally perpendicular to the locking rod 44. Once the proximal ends 47,43 of the locking member 40 and recess 42 are engaged, the operator can push the distal end 49 of the locking member downwards so as to rotate the locking member about the second pivot pin 52 and into full, flush engagement in the recess. As this rotation of the locking member 40 into the recess 42 takes place the locking rod 44 pulls the second end 18 of the first body member into contact with the second end 22 of the second body member 14, thus closing the collar tightly around the shaft in the same manner as an over centre latch arrangement.

In order to ensure that the collar is not inadvertently opened in service, the optional safety catch arrangement may be included on the collar. As the distal end 49 of the locking member 40 enters the distal end 45 of the recess 42, the spring-biased catch 62 will enter the niche 60 and lock the locking member into the recess. The release the locking member 40 from the recess 42, the technician must pull back on the catch against the biasing force of the spring 64 and the locking member can then be rotated outwards around the second pivot pin 52 and out of the recess to open the collar for removal.

The collar of the present invention does not require any tools or fixtures in order to close it around a shaft. Thus, the possibility of a technician damaging the fixtures or the collar itself during installation or removal is eradicated, so increasing the longevity of the collar in service. With the technician no longer having to carry and use tools the installation and removal procedures are quicker than with existing collar arrangements, and no longer needing to use hand tools also reduces the risk of injury to the technician.

The optional arrangement for the locking rod and pivot pins to be adjustable via mutually engageable threaded surfaces ensures that the collar clamping force can be optimised for specific applications.

Furthermore, where the collar body members and locking member are formed from a thermoplastic material such as, for example, the aforementioned cast polyamide material there is a still further safety benefit given the significant reduction in weight of the collar itself. A thermoplastic collar is much safer for technicians to handle and install, thus reducing the likelihood of serious hand injuries which have been known to occur during handling and installation of traditional metal collars. Finally, using a thermoplastic collar also removes the wear caused by metal collars rubbing on other metal components of the shaft and/or shaft bearing.

In the preferred embodiment of the collar described above, the locking recess has a proximal end surface and a distal end surface but no side surfaces. However, whilst this it is preferred for easy handling of the locking member to have the sides of the locking member flush with the upper and lower surfaces of the second body member when the locking member is in the recess the invention is not limited to this arrangement. Instead, the recess may alternatively be located inwardly of one or both of the upper and lower surfaces of the second body member such that the locking recess has not only proximal and distal end walls but at least one side wall as well. In this alternative arrangement, the optional niche and safety catch may be located on the side wall of the recess and side of the locking member, respectively, instead of on the respective distal ends thereof.

This and other modifications and improvements may be incorporated without departing from the scope of the present invention.