GB1601910A - Roller conveyors - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO ROLLER CONVEYORS (71) We, TRANSPOR1TEKNIK GUNNAR EKSTRAND AB, a company duly organised under the laws of Sweden, of Koppargatan 5,5-271 00 YSTAD, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to a roller conveyor with rollers which are each mounted by means of bearing pieces, on a through-shaft journalled in the frame of the conveyor.

Roller conveyors of the above type are used to a great extent industrially for the transport of goods. Irrespective of whether the rollers of the roller conveyor are driven or not, the bearings of the shaft and rollers are exposed to very great stresses, the roller bearings being particularly greatly exposed because of the great flexural stresses caused by the goods. Stresses on the bearings entail that these must often be replaced, with resulting considerable costs. A particular problem in this context is so-called accumulating roller conveyors, that is to say conveyors where goods are transported and stopped while retaining driving power on the rollers, in order, for example, to be rerouted to another conveyor or receptacle point. Rollers for such conveyors have hitherto been designed with smooth friction bearings of the radial or axial type.Inclination in the bearing because of flexural stress on the roller has, here, a destructive abrasive effffect on the bearing surfaces. Breakdown in the bearing system normally means that the entire roller must be replaced.

It is previously known from DT-AS 1, 065,773 to provide flexible undriven rollers of rubber, for example, for supporting elastically yieldable belts when the downward bending of the roller is of importance for the function of the apparatus.

In such cases, the roller must be easily shiftable on its support in order that this downward bending be able to take place and the supporting pieces must be journalled on stub shafts with bulbous ends.

A device for foodstuff transport is known from U.S. Patent Specification No. 3,931, 878 which also has stub shafts with bulbous ends, but in this case in order to make possible easy dismantling for purposes of cleaning the apparatus, Stub shafts of this type are unusable for obviating the above- mentioned problem, since wear on bearings and the risk for breakdown is even greater in the last-mentioned type.

The object of this invention is to greatly improve the journalling of rollers in roller conveyors to the extent that stresses and, thereby, wear on the bearing is considerably reduced, even to such a degree that horizontally driven accumulating roller conveyors may economically be used instead of undriven sloping conveyors, for example, in so-called transition depots.

According to the invention, a roller conveyor comprises a pair of side frame members, substantially rigid roller shafts journalled in bearings on said side frame members, solid comparatively rigid bearing pieces fixed on each roller shaft in axially spaced relationship, a relatively less rigid conveyor roller for each roller shaft and having rigid end pieces engaged supportively with said bearing pieces, each said end piece having an axially outer end face defining one end face of said conveyor roller and extending axially inwardly thereof to a point near the inner end of one bearing piece, said end piece further including a bearing insert having a surface engaging a surface of said bearing piece, either one of the engaging surfaces of each bearing piece and its co-operating bearing insert being cylindrical and the other being gently arched of the conveyor roller, or both engaging surfaces being gently arched axially of the conveyor roller, and said insert and at least the engaging surface portion of each bearing piece being formed of specifically different compatible low friction materials. Preferably, the compatible low friction materials are plastics and steel.

The present invention will be described in greater detail hereinbelow with reference to the accompanying drawing which illustrates in axial section one embodiment of the invention.

On the drawing, there is shown a roller 10 which consists of a sheet metal casing 11, end pieces 12 being fixed in a suitable manner in the ends of the casing.

The end pices 12 have a central opening along the periphery of which is fixed an annular bearing insert 13 of steel. The bearing insert 13 has a cylindrical inner surface 14. The roller 10 is supported by a shaft 15 with the assistance of sheathshaped bearing pieces 16 which are passed on the shaft 15. The bearing pieces 16 project with a portion into the central opening of the end pieces 12, this portion having an arched bearing surface 17 which with substantially linear contact abuts against the bearing surface 14 of the annular bearing insert 13. The portion of the bearing pieces 16 provided with the axially arched bearing surface 17 is defined by an abutment 18 which counteracts axial movement of the roller 10 relative to the bearing pieces 16 and the shaft 15, respectively.

The bearing pieces 16 are connected to the shaft 15 each by means of a locking pin 19 which extends diametrically through the bearing piece and the shaft. As is shown to the left of the drawing, a sprocket wheel 20 can be provided integrally with the bearing piece 16, the sprocket wheel 20 engaging with a drive chain 21 for rotation of the shaft 15 and the roller 10 by means of the friction which occurs between the bearing pieces 16 and the annular bearing inserts. The sprocket wheel can also be of, for example, steel and be fixed to the bearing piece 16.

The ends of the shaft 15 are journalled in a frame 24 by means of ball bearings 22 which are fixed in cages 23 which are fixedly screwed to opposing surfaces on the frame 24.

With a roller 10 which is mounted on the shaft 15 in the above-described manner, the stresses on the bearings of the roller on flexural stresses of the shaft are to a great extent reduced thanks to the arcing of the bearing surface 17 of the bearing pieces 16 and because of the fact that the mutally abutting bearing surfaces are of different material, namely steel and plastics.

A considerable advantage in the invention is, moreover, that the bearings of the roller 10 and the shaft 15 may be replaced easily and rapidly. On replacement of the bearing pices 16, the locking pin 19 is quite simply tapped out, the old bearing piece 16 is removed by withdrawal or dismemberment and a new bearing piece 16 is mounted and locked in place. On replacement of the ball bearings 22, t1. cages 23 are first unscrewed and a new cage 23 is scre vzl in plae.

The important arched surface 17 need not, naturally, be disposed on the bearing pieces 16 but may just as well be disposed on the annular bearing inserts 13. Naturally, it is possible that both the bearing surface 17 and the bearing surface 14 be arched in the axial direction. Similarly, the bearing pieces 16 may naturally be produced in steel and the bearing inserts 13 in plastics. Other materials can also be used for this purpose, the major requirement being that they be compatible as regards friction.

By means of the above-described apparatus, roller conveyors can be produced which have considerably improved bearing working life and whose bearings may easily be replaced if necessary.

The construction parts which are utilized may be, moreover, of cheap material, for which reason a roller conveyor manufactured according to the invention displays considerable advantages also as regards economy. A particular advantage inherent in the apparatus according to the present invention is that by applying the the inventive conception it is possible to manufacture driven accumulating roller conveyors without risk of rapid wear of the bearings. The reason for this is that when the rollers 10 are stationary, the slippage between the bearing surfaces 14 and 17 occurs only at the point of linear contact and it will be apparent that because of the arched surfaces, no increase of the fiexural stresses will occur when the roller is bent because of heavy loading.

WHAT WE CLAIM IS: 1. A roller conveyor comprising a pair of side frame members, substantially rigid roller shafts journalled in bearings on said side frame members, solid comparatively rigid bearing pieces fixed on each roller shaft in axially spaced relationship, a relatively less rigid conveyor roller for each roller shaft and having rigid end pieces engaged supportively with said bearing pieces each said piece having an axially outer end face defining one end face of said conveyor roller and extending axially inwardly thereof to a point near the inner end of one bearing piece, said end piece further including a bearing insert having a surface engaging a surface of said bearing piece, either one of the engaging surfaces of each bearing piece and its co-operating bearing insert being cylindrical and the other being gently arched axially of the conveyor roller, or both engaging surfaces being gently arched axially of the conveyor roller, and said insert and at least the engaging surface portion of each bearing piece being formed

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   to the accompanying drawing which illustrates in axial section one embodiment of the invention.

   On the drawing, there is shown a roller 10 which consists of a sheet metal casing 11, end pieces 12 being fixed in a suitable manner in the ends of the casing.

   The end pices 12 have a central opening along the periphery of which is fixed an annular bearing insert 13 of steel. The bearing insert 13 has a cylindrical inner surface 14. The roller 10 is supported by a shaft 15 with the assistance of sheathshaped bearing pieces 16 which are passed on the shaft 15. The bearing pieces 16 project with a portion into the central opening of the end pieces 12, this portion having an arched bearing surface 17 which with substantially linear contact abuts against the bearing surface 14 of the annular bearing insert 13. The portion of the bearing pieces 16 provided with the axially arched bearing surface 17 is defined by an abutment 18 which counteracts axial movement of the roller 10 relative to the bearing pieces 16 and the shaft 15, respectively.

   The bearing pieces 16 are connected to the shaft 15 each by means of a locking pin 19 which extends diametrically through the bearing piece and the shaft. As is shown to the left of the drawing, a sprocket wheel 20 can be provided integrally with the bearing piece 16, the sprocket wheel 20 engaging with a drive chain 21 for rotation of the shaft 15 and the roller 10 by means of the friction which occurs between the bearing pieces 16 and the annular bearing inserts. The sprocket wheel can also be of, for example, steel and be fixed to the bearing piece 16.

   The ends of the shaft 15 are journalled in a frame 24 by means of ball bearings 22 which are fixed in cages 23 which are fixedly screwed to opposing surfaces on the frame 24.

   With a roller 10 which is mounted on the shaft 15 in the above-described manner, the stresses on the bearings of the roller on flexural stresses of the shaft are to a great extent reduced thanks to the arcing of the bearing surface 17 of the bearing pieces 16 and because of the fact that the mutally abutting bearing surfaces are of different material, namely steel and plastics.

   A considerable advantage in the invention is, moreover, that the bearings of the roller

   10 and the shaft 15 may be replaced easily and rapidly. On replacement of the bearing pices 16, the locking pin 19 is quite simply tapped out, the old bearing piece 16 is removed by withdrawal or dismemberment and a new bearing piece 16 is mounted and locked in place. On replacement of the ball bearings 22, t1. cages 23 are first unscrewed and a new cage 23 is scre vzl in plae.

   The important arched surface 17 need not, naturally, be disposed on the bearing pieces 16 but may just as well be disposed on the annular bearing inserts 13. Naturally, it is possible that both the bearing surface 17 and the bearing surface 14 be arched in the axial direction. Similarly, the bearing pieces 16 may naturally be produced in steel and the bearing inserts 13 in plastics. Other materials can also be used for this purpose, the major requirement being that they be compatible as regards friction.

   By means of the above-described apparatus, roller conveyors can be produced which have considerably improved bearing working life and whose bearings may easily be replaced if necessary.

   The construction parts which are utilized may be, moreover, of cheap material, for which reason a roller conveyor manufactured according to the invention displays considerable advantages also as regards economy. A particular advantage inherent in the apparatus according to the present invention is that by applying the the inventive conception it is possible to manufacture driven accumulating roller conveyors without risk of rapid wear of the bearings. The reason for this is that when the rollers 10 are stationary, the slippage between the bearing surfaces 14 and 17 occurs only at the point of linear contact and it will be apparent that because of the arched surfaces, no increase of the fiexural stresses will occur when the roller is bent because of heavy loading.

   WHAT WE CLAIM IS: 1. A roller conveyor comprising a pair of side frame members, substantially rigid roller shafts journalled in bearings on said side frame members, solid comparatively rigid bearing pieces fixed on each roller shaft in axially spaced relationship, a relatively less rigid conveyor roller for each roller shaft and having rigid end pieces engaged supportively with said bearing pieces each said piece having an axially outer end face defining one end face of said conveyor roller and extending axially inwardly thereof to a point near the inner end of one bearing piece, said end piece further including a bearing insert having a surface engaging a surface of said bearing piece, either one of the engaging surfaces of each bearing piece and its co-operating bearing insert being cylindrical and the other being gently arched axially of the conveyor roller, or both engaging surfaces being gently arched axially of the conveyor roller, and said insert and at least the engaging surface portion of each bearing piece being formed

   of specifically different compatible low friction materials.
2. 2. A roller conveyor as claimed in Claim 1, wherein said bearing piece is formed of steel and said bearing insert is formed of plastics material.
3. 3. A roller conveyor as claimed in Claim 1, wherein said bearing pieces each have a radial shoulder disposed axially outwardly of one said end pieces to limit end play in each conveyor roller.
4. 4. A roller conveyor as claimed in Claim 3, including a driving rotational element fixed on one of said bearing pieces, and driving means engaging said driving element.
5. 5. A roller conveyor substantially as hereinbefore described with reference to the accompanying drawing.