GB2089938A

GB2089938A - Conveyor rollers

Info

Publication number: GB2089938A
Application number: GB8138102A
Authority: GB
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1980-12-20
Filing date: 1981-12-17
Publication date: 1982-06-30
Also published as: FR2496610B3; IT1142612B; FR2496610A1; IT8125710A0

Abstract

A roller of a roller conveyor has an outer casing 3 supported in side members 1 of the conveyor frame by stub shafts 8 forming inner races of bearings having outer races 6 supported in resilient supports 5 mounted in the casing ends. <IMAGE>

Description

SPECIFICATION Improvements in conveyors Conveyors are known in which rollers are supported by shafts fixed to side members of a conveyor frame. The rollers may define a track for the articles to be conveyed or may serve to guide a belt. The known rollers are difficult to mount in place and expensive to produce. Alignment of the rollers also presents difficulties. Furthermore, the rollers transmit vibrations to the side members of the frame so that noise is produced in operation and sound damping is difficult.

To overcome this problem, it is herein proposed that members serving as the outer races of bearings for the roller are held in resilient support rings and that members serving as the inner races constitute journals arranged to support the roller from the side members of the conveyor. The resilient support rings, preferably formed from rubber or plastics with a Shore hardness of substantially 80 effectively damps sound vibrations and restricts their transmission from the outer casing of the roller to the journals. The resilience of the supports also permits subsequent correction of a support roller relative to the side members, because errors of alignment and differences in interval are accommodated by the resilient nature of these supports.The supports fit tightly within the casing and prevent water from entering the casing interior and causing rusting and damage to the good to be transported, owing to rust breaking through to the exterior of the rollers. Preferably, the material of each support ring is such that the electrical resistance between the casing and the journals is at most 100 million Ohms so that the roller casing is not electrostatically charged.

Preferably, each support ring has a peripheral portion and a web portion which together define the generally cylind.ical cavity. The associated inner member which serves as the inner bearing race and journal is arranged to be movable relative to the roller between a retracted position in which it may bear against the web of the support ring and an extended position in which it is spaced from the web and projects from the end of the roller. With the inner members in their retracted positions, the overall length of the roller (including the journals) may be made less than the internal spacing of the side members of the conveyor.

Consequently, with the inner members retracted, the roller may be offered up and the journals aligned with apertures in the side members. The inner members may then be extended into the apertures to mount the roller in place.

Convenienily, each of the inner members screwably cooperates with a fixing member to secure it to the side member. Conveniently, the fixing member is a screw which is received within a screw-threaded recess within the inner member.

With the inner member engaged with the base of the cavity of the bearing support member, the two parts are locked together, and insertion of the screw facilitated.

Accordingly, it is further proposed that a roller for a roller conveyor should comprise a tubular outer casing member, each end of which receives a bearing support ring defining a generally cylindrical cavity having an outer bearing shell against which run the rolling members of the bearing, an inner track for the rolling members being provided by a stub shaft within which is received a securing screw, the stub shaft being movable between an extended fixing position projecting from the roller, and a retracted position engaging the base of the cavity of the support ring so as to be rotatable with the casing member.

Preferably, each support ring has a peripheral rib serving as an abutment for the end of the outer casing, which may be provided at each end with a taper against which the stop rests. The peripheral surface of each support ring may have longitudinal grooves to permit displacement of the material of the ring following its insertion into the casing. As an alternative to the direct insertion of the support rings into the casing, each ring may have an external peripheral groove which receives a lip at the end of a sleeve engaging the inner surface of the casing. The sleeve and the casing may then have complementary tapers.

The stub shaFt may have a portion of reduced diameter which enters an aperture in one of the side members of the conveyor frame. The length of this portion is preferably less than the thickness of the side member so that when the screw is tightened, the side member is gripped between the head of the screw and the remaining part of the stub shaft. The aperture is conveniently in the form of an elongate slot which may extend parallel to the length of the support member, thereby permitting adjustment of the roller relative to the support member. Such adjustment may be necessary in order to deflect the belt of a belt conveyor or to deflect the driving belt of a roller conveyor provided with driven rollers.During this adjustment, the roller in accordance with the present proposal is easily arranged obliquely relative to the conveyor track without the bearings being overstressed. This advantage is made possible by supporting the bearings in the resilient support rings.

Each member, or stub shaft, serving as the inner race of a bearing is preferably provided with a milled track for the rolling elements, which are therefore guided relative to this member. In the event that the rolling element are balls, the track has a circumferential channel of arcuate crosssection. The member which serves as the outer race of the bearing desirably has a cylindrical bearing surface to permit axial adjustment of the inner member for the purposes of assembly as described above, and to permit variations in spacing between the facing surfaces of the conveyor side members. Each member serving as the outer race preferably has a radially inwardly projecting lip on the side of the running surface for the rolling elements nearer the end of the roller so as to limit the movement of the rolling elements towards the end of the roller.An outwardly projecting lip may be provided at the end of the member further from the end of the roller, this lip being received within a groove in the resilient support ring. A gasket or seal may surround the stub shaft and compensate for variations in the spacing between the bearing and the side member of the conveyor frame.

The web of the resilient support ring may have a polygonal depression in the side facing the member which serves as the inner race of the bearing. The depression serves to receive a complementary shaped portion at the end of the inner member so as to ensure an interlocking action between these two parts. Interengagement of the profiled end of the inner member and the depression in the web of the support ring may be facilitated by the provision of complementary bevelled edges.

Preferably, the depression and the profiled portion have bevels on four sides, the bevels being not so long that a square is formed with pronounced corners. It is sufficient if the bevelling has rounded corners so as to approximate a square.

In the drawings: Figure 1 shows one end of a first embodiment of roller in axial section, the upper part of the tigure showing the roller before assembly and the lower part of the figure showing the roller in its assembled position, Figure 2 shows the opposite end of the roller showing a second embodiment, Figure 3 shows the bearing and bearing support of the embodiment of Figure 1, Figure 4 shows the bearing and bearing support of the embodiment of Figure 2, Figure 5 shows the form of aperture in the conveyor frame side member, Figure 6 is a view similar to Figure 4 but of a modification, Figure 7 is a detail of part of the bearing support ring shown in Figure 6, as viewed axially of the ring, and Figure 8 shows the end of the inner race of the modification shown in Figure 6, likewise viewed axially.

Referring to the drawings, a roller conveyor comprises lateral cheeks or support members 1 with longitudinally spaced apertures 1 a for mounting in place the journals of a series of rollers 2 defining the conveyor track. Several different embodiments and modifications of the rollers are shown in the drawings. Figures 1 and 2 when viewed together show the opposite ends of two embodiments. Figure 2 shows the roller mounted in place whereas, above the centre line, Figure 1 depicts the roller in the position in which it is offered up to the cheeks of the conveyor, and below the centre line the roller mounted in place.

Each of the embodiments and modifications of roller comprises an outer casing part 3, the ends 3a of which are tapered inwards to engage and retain resilient bearing support rings 5. in the following, description will be given of a single one of the support rings and of the associated parts, it being understood that in general a practical embodiment of roller will have two identical support rings. In the construction shown in Figure 1 , the support ring has an outer metallic sleeve 4 whereas this is omitted in the Figure 2 embodiment, as will later be described.

The sleeve 4 shown in Figure 1 has an inwardly directed peripheral lip 4b engaged in a groove in the resilient support to locate the sleeve relative to the ring. Before assembly, the casing may have a constant diameter throughout its length and the sleeve 4 may have an out-turned periphcral lip 4a for abutment with the end of the casing in order to limit the distance by which the support ring may be inserted into the casing. Following insertion, the end of the casing is swaged to give it and the sleeve the taper shown in Figure 1. The support ring has a groove Sc for receiving the deformed end of the sleeve.

The bearing support ring has an annular outer wall portion or rim and a web 5a, the rim and web together defining a cylindrical cavity. The ring is formed in one piece from natural or synthetic rubber or other elastomer with a Shore hardness of about 80 and such as to offer an electrical resistance of not more than 100 million Ohms.

Fitted within the cavity so as to be tightly embraced by the rim portion is an outer bearing shell 6 which serves as the outer race of a ball bearing. The shell has a cylindrical portion 6a providing a track for the balls held in a cage 11 and an arcuately in-turned rim 7 serving as a guide to limit lateral movement of the balls. At its other end, the shell 6 has an out-turned lip Sc engaged in a groove between the rim and web portions so as to fix the shell in place. The inner race for the balls is formed by a stub shaft 8, which also serves as a journal, the ball track being formed by a groove of arcuate section matching the radius of the balls.Clearly, within the scope of the present proposal, the balls can be replaced by rollers conveniently of barrel shape ip which evant the ball track in the stub shaft is profiled appropriately.

The stub shaft is hollow and has an internal screw thread 8a. The thread 8a is complementary to that of a bolt 9 having a head somewhat wider than the aperture 1 a within which an end portion 8b of the stub shaft may be received. The end portion 8b is of reduced, polygonal cross-section so as to be a fit within the aperture which, as shown in Figure 5, is formed by an elongate slot.

The length of the reduced portion 8b is slightly less than the thickness of the conveyor side member 1. In this way, when the bolt 9 is fully tightened within the stub shaft, the side member is gripped tightly between the annular surface of the stub shaft surrounding the portion 8b and the head of the bolt, or washers interposed between the side member and the head of the bolt. The roller may be adjusted horizontally in the apertures 1 a particularly for the purpose of varying the deflection of a driving or support belt.

Before assembly, both stub shafts of the roller are disposed in retracted positions as shown above the centre line in Figure 1. The end of the stub shaft bears against the web 5a of the support ring 5. In this position, the roller is offered up to the conveyor frame. The stub shafts are now fast with the casing of the roller so that the roller may be turned in order to position the portion 8b ready for introduction into the aperture. The shank of the bolt 9 may now be passed through the aperture into the threaded bore of the stub shaft and screwed into the initial turns of the thread without the stub shaft being constrained to rotate with the bolt.The stub shaft may now be drawn into the position shown beneath the centre line in Figure 1 and the bolt screwed home, rotation of the stub shaft now being prevented by cooperation of the flanks of the portion 8b with the edges of the slot.

The overall length of the roller is such that, when one of the stub shafts is drawn into its fixed position in the associated side member of the conveyor frame, the other stub shaft is frictionally connected to the casing by way of the web 5a. By displacing the roller axially, the other stub shaft may be pressed resiliently against the internal face of the other side member. By rotating the roller, this other stub shaft is rotated by frictional contact until the portion 8b enters the pertaining aperture.

Following the tightening of both bolts, clearances are produced between both bolts and the webs 5a. The support roller is then rendered freely rotatable.

Referring again to Figure 2, the bearing support ring 5 has a bevel 5f which presents the ring being compacted during insertion. Under pressure, the ring 5 has a bevel 5f which prevents the ring being reduced in diameter to such an extent that it is easily inserted into the casing. Axially extending grooves 5e in the peripheral surface of the ring permit balancing of material. The ring has a lip 5g which limits rhe depth of insertion of the ring into the casing. A sealed ring 10 is provided on the larger diameter part of the stub shaft between the outer bearing shell 6 and the side member of the conveyor frame. This seal ring is compressed when the roller adopts the position shown in chain lines.

In the modification shown in Figures 6 to 8, each of the stub shafts is chamfered at four sides in order to form a tapering protrusion 13. the chamfers meet the end face of the stub shaft in straight edges which are too short to intersect and form a perfectly square protrusion with pronounced corners. The web 5a of the resilient support ring has a depression 12 which is complementary to the protrusion 13, having four sloping sides meeting in rounded corners.

Cooperation of the protrusion with the depression facilitates the interlocking of the stub shaft and bearing support ring, with more certainty than the frictional contact possible with the embodiments described previously.

Claims

1. A roller for a roller conveyor, wherein members serving as the outer races of bearings for the roller are held in resilient support rings and members serving as the inner races constitute journals arranged to support the roller from side members of the conveyor.

2. A roller as claimed in claim 1, wherein each support ring has a peripheral portion and a web portion, together defining a generally cylindrical cavity.

3. A roller as claimed in either preceding claim, wherein the members serving as the races of each bearing are relatively axially movable.

4. A roller as claimed in claim 2, wherein each member serving as the inner race is movable between a position in which it bears against the web uf the associated support ring and a position spaced therefrom.

5. A roller as claimed in claim 3 or claim 4, wherein each member serving as the inner race has a non-circular protrusion for reception in a complementary depression in the web of the associated support ring.

6. A roller as claimed in claim 5, wherein the edges of the depression and protrusion are bevelled.

7. A roller as claimed in claim 5 or claim 6, wherein the depression and protrusion are each four sided.

8. A roller as claimed in any preceding claim, wherein each support ring is formed from an elastomer with a Shore hardness of substantially 0.

9. A roller as claimed in any preceding claim, wherein the electrical resistance between a casing of the roller and the journal is at most 100 million Ohms.

10. A roller as claimed in any preceding claim, wherein each support ring has a peripheral rib for locating the ring relative to an end of the casing.

1 A roller as claimed in claim 10, wherein the casing has a radially inwardly tapered portion at each of its ends.

12. A roller as claimed in any preceding claim, wherein sach support ring has axially extending longitudinal grooves in its peripheral surface.

13. A roller as claimed in any of claims 1 to 1 wherein each ring has a circumferentially extending external groove in which is received a lip of a sleeve retained within an end of the casing.

14. A roller as claimed in any preceding claim, wherein each member serving as an inner race has an internally screw-threaded recess for reception of a screw for mounting the roller in the side members of the conveyor.

1 5. A roller as claimed in any preceding claim, wherein each member serving as an inner race has a track for receiving rolling members.

1 6. A roller as claimed in claim 15, wherein the track is of arcuate axial section.

1 7. A roller as claimed in any preceding claim, wherein each member serving as an outer race has a cylindrical running surface for the rolling members.

18. A roller as claimed in claim 14, wherein each member serving as an outer race has an inwardly projecting lip on the side of the running surface near the end of the roller.

1 9. A roller as claimed in any preceding claim, wherein each member as an outer race has an outwardly projecting lip at the end further from the end of the roller, said lip being received within a groove in the support ring.

20. A roller as claimed in any preceding claim in a conveyor having a frame with side members, wherein each inner race has a projecting portion received in an aperture of a respective side member.

21. The conveyor claimed in claim 20, wherein the projecting portion is of reduced cross-section and has a length less than the thickness of the side member.

22. The conveyor claimed in claim 21, wherein the projecting portion is of polygonal crosssection.

23. The conveyor claimed in claim 21 or claim 22, wherein each aperture is in the form of a slot.

24. The conveyor claimed in any of claims 20 to 23, wherein a seal surrounding a portion of each member serving as an inner race external of the roller is disposed between the bearing and the support member.

25. A roller for a roller conveyor comprising a tubular outer casing member, each end of which receives a bearing support ring defining a generally cylindrical cavity having an outer bearing shell against which run the rolling members of the bearing, an inner track for the rolling members being provided by a stub shaft within which is received a securing bolt, the stub shaft being movable between an extended fixing position projecting from the roller and a retracted position engaging the base of the cavity of the support ring so as to be rotatable with the casing member.

26. A roller conveyor including a roller comprising an outer tubular casing, a resilient bearing support in each end of the casing, each bearing support having therein a casing receiving an outer bearing shell with a radially outwardly projecting lip engaged in a peripheral groove at the base of the cavity, the shell further having ari inwardly directed lip adjacent the end of the roller to retain rolling elements which engage a track on an inner race, an extended portion of which projects from the roller and has at its free end a portion of reduced cross-section which is received non-rotatably within an aperture within a side member of the conveyor and is held in place by means screwably cooperating with said extended portion.

27. A roller of a roller conveyor substantially as hereinbefore described with reference to and as illustrated in any of Figures 1 to 4 or Figures 7 to 3 of the drawings.