Hygienic Sprocket Wheel

Abstract

Sprocket wheel for use in a conveying structure of the type where a conveyor belt is assembled from a plurality of similar modular belt links, where the sprocket wheels are designed to engage, guide and drive the conveyor belt, wherein the sprocket wheel comprises a central area suitable to be arranged and fastened on a drive axle, and a plurality of drive teeth arranged along and projecting from the periphery of the central area of the sprocket wheel, wherein said sprocket wheel has a peripheral surface area between adjacent drive teeth, where at most 15% preferably only 10% or less of said peripheral surface area in use is in engagement with the conveyor belt.

Claims

1. Sprocket wheel for use in a conveying structure of the type where a conveyor belt is assembled from a plurality of similar modular belt links, where the sprocket wheels are designed to engage, guide and drive the conveyor belt, wherein the sprocket wheel comprises a central area comprising an aperture, suitable to be arranged and fastened on a drive axle, where the inner periphery of the aperture is provided with axle engagement sections separated by cut-outs, not adapted to engage the drive axle, and where a plurality of drive teeth are arranged along and projecting from the periphery of the central area of the sprocket wheel, wherein said sprocket wheel has a peripheral surface area between adjacent drive teeth, where at most 15% preferably only 10% or less of said peripheral surface area in use is in engagement with the conveyor belt and where the sprocket wheel is in two or more sections, where the two or more sections may be assembled around the axle, forming a complete circumference with the projecting teeth substantially evenly spaced along the periphery.

2. Sprocket wheel according to claim 1, wherein the drive teeth arranged along and projecting from the periphery of the central area of the sprocket wheel has a distal end furthest from the central area, where each drive tooth has a seating surface connecting to the distal end, where said seating surface has a lower section radially distanced inwards towards the central area relative to the distal end and said lower end of the seating surface projecting forwards in the intended rotation direction, such that the modular belt link will be carried on the seating surface not engaging the peripheral surface between adjacent teeth.

3. Sprocket wheel according to claim 2, wherein the periphery between adjacent drive teeth comprises cut-outs, such that the distance between the centre of the sprocket wheel and the closest part of the cut-out with respect to the centre is less than the distance between the centre of the sprocket wheel and the periphery.

4. Sprocket wheel according to claim 1, wherein a ridge or crest is arranged projecting from the peripheral surface, between adjacent drive teeth, such that the underside of the conveyor belt may engage said crest or ridge whereby in use the crest or ridge minimizes the engagement area or contact surface between the sprocket wheel and the conveyor belt.

5. Sprocket wheel according to claim 4, wherein said ridge or crest is arranged along the periphery of the central area.

6. Sprocket wheel according to claim 4, wherein said ridge or crest is arranged orthogonal to the periphery of the central area.

7. Sprocket wheel according to claim 1 where, when the sprocket wheel is in two or more sections, each section has two substantially radial diverging sides connecting the periphery to an aperture provided centrally in the central area said aperture allowing the drive axle to pass through the sprocket wheel, where adjacent radial diverging sides means are provided for assembling adjacent sections around the drive axle.

Description

DESCRIPTION OF THE DRAWING

[0024] The invention will now be described with reference to the accompanying drawings wherein

[0025] FIG. 1 illustrates an end section of a conveying structure

[0026] FIG. 2 illustrates a prior art sprocket wheels

[0027] FIG. 3 illustrates a prior art sprocket wheel

[0028] FIG. 4 illustrates a sprocket wheel according to the invention in the two part form

[0029] FIG. 5 illustrates the embodiment of FIG. 4 is illustrated in a side-view

[0030] FIG. 6 illustrates a close-up of the engagement between the conveyor belt and the sprocket wheel

[0031] FIG. 7 illustrates an embodiment of the present invention

[0032] FIG. 8 illustrates an embodiment of the present invention

[0033] FIG. 9 illustrates an embodiment of the present invention

[0034] FIG. 10 illustrates a cross-section through a part of a sprocket wheel

[0035] FIG. 11 illustrates the ridge or crest arranged perpendicular to the plane of the sprocket wheel

DETAILED DESCRIPTION OF THE INVENTION

[0036] In FIG. 1 is schematically illustrated an end section of a conveying structure, said conveying structure comprising a conveyor belt 1 assembled from a plurality of substantially identical modular belt links 2. The modular belt links 2 are assembled in a hinge-like fashion by inserting a pin 3 interconnecting adjacent belt links, such that the modular belt links 2 may articulate around the pin, for example when being curved/bent around a sprocket wheel.

[0037] The end of the conveying structure is provided with a sprocket wheel 10 where the sprocket wheel along a periphery 11 is provided with guide teeth 12. In this connection the periphery shall be understood as an outer circumference of the sprocket wheel 10 from which drive teeth 12 project substantially radially away from the centre of the sprocket wheel. In the centre of the sprocket wheel 10 is provided an aperture 13 through which aperture 13 an axle either a drive axle or just a rotating axle may be fitted in order to allow the sprocket wheel 10 to rotate around the axle 13.

[0038] The distance between adjacent drive teeth 12 is designed such that the drive teeth 12 will engage into recesses provided in the underside of a conveyor belt 1 and an edge of the drive teeth 12 will engage an engagement point/face provided in the conveyor belt 1 in order to propel the conveyor belt.

[0039] In FIGS. 2 and 3 are illustrated prior art sprocket wheels 10′, 10″ where both sprocket wheels 10′, 10″ are provided with drive teeth 12 substantially evenly distributed along the periphery of the sprocket wheel 10′, 10″. The material thickness of the sprocket wheels provides for a periphery surface, i.e. the surface of the periphery connecting the two side faces 14, 14′ only one side surface 14 is visible. In a central part of the sprocket wheel 10′, 10″ is provided an aperture 13′, 13″. As is the case already explained above with reference to FIG. 1 the apertures 13′, 13″ serve to fit the sprocket wheel 10 onto a drive axle. In order to transfer the drive forces, i.e. the torque from the not-illustrated axle to the sprocket wheel 10′, 10″ the sprocket wheel 10′ is provided with a square aperture such that a square axle fitted inside the aperture 13′ will engage and transfer torque forces to the inner sides 15 of the aperture 13′.

[0040] In the embodiment illustrated in FIG. 3 the aperture 13″ is circular and the axle which will transfer torque forces to the sprocket wheel 10″ is provided with a groove such that a wedge may be inserted in the groove in the axle (not illustrated) and at the same time engage the groove 16 provided in the sprocket wheel. In this manner torque forces are transferred from the axle fitted in the aperture 13″ via the wedge to the sprocket wheel 10″.

[0041] In the embodiments illustrated with reference to FIGS. 1, 2 and 3 the drive teeth 12 fit inside an aperture provided in the conveyor belt, such that one side face of the drive tooth will engage the conveyor belt and thereby transfer the force to the conveyor belt which is then moved.

[0042] Between two drive teeth 12 is a substantially flat periphery surface which will support the conveyor belt as the conveyor belt is turned around the sprocket wheel.

[0043] With reference to FIG. 4-6 an embodiment of the present invention will be explained.

[0044] In FIG. 4 a sprocket wheel according to the invention, in this embodiment in the two part form comprising two sections 21, 22 is illustrated. Along the periphery of the sprocket wheel 10 are substantially evenly spaced drive teeth and as may be seen in FIG. 4 a conveyor belt 1 is arranged on the sprocket wheel 10 such that the drive teeth are inserted into apertures 4 in the conveyor belt.

[0045] As the sprocket wheel 10 is rotated, the drive teeth 12 will engage the conveyor belt and thereby propel the conveyor as explained above. In FIG. 5 the embodiment of FIG. 4 is illustrated in a side-view where it is obvious that the drive teeth 12 are inserted in apertures 4 created in the conveyor belt 1.

[0046] In this embodiment the central aperture 13 has a general square cross section, however, a number of cut-outs 24 are provided such that the engagement surfaces 15 are kept at a minimum, but are slightly reinforced, i.e. have a larger width than the sprocket wheel itself in order to be able to absorb the torque forces delivered by the drive axle (not illustrated). The cut-outs and the limited engagement surfaces 15 provide the possibility of being able to clean thoroughly around the central aperture 13 in order to achieve the high hygienic standards.

[0047] With reference to FIGS. 6 and 9 one embodiment of the inventive concept of the invention is illustrated. FIG. 6 is a close-up of the engagement between the conveyor belt and the sprocket wheel as seen in FIG. 5. The periphery 11 of the sprocket wheel 10 is provided with a ridge 30 extending from the periphery surface 31. In this context as already mentioned above the periphery surface 31 shall be understood as the surface of the periphery between two drive teeth 12. The ridge 30 causes the engagement with the modular conveyor belt link 2 to be elevated from the main part of the periphery surface and therefore allows for cleaning of a large part of the periphery surface even during engagement with the modular belt links 2.

[0048] In FIG. 10 is schematically illustrated a cross-section through a part of a sprocket wheel 10 where the ridge or crest 31 is clearly indicated. A drive tooth 12 is illustrated in dashed lines.

[0049] It is clear that if the ridge or crest 31 is arranged perpendicular to the plane of the sprocket wheel 10 as illustrated in FIG. 11 by the ridge or crest 31′ the same effect is achieved, i.e. that the modular conveyor belt link 2 as illustrated in FIG. 6 is elevated slightly from the main part of the periphery surface 31.

[0050] In a further embodiment of the invention as illustrated in FIGS. 7 and 8 the drive teeth arranged along and projecting from the periphery 11 of a central area of the sprocket wheel 10 are arranged such that each drive tooth 12′ has a seating surface 33 connecting to the distal end 34 of the drive tooth. The seating surface 33 has a lower section 35 projecting in the circumferential direction in the direction of the intended rotation direction as indicated by arrow 40, relative to the distal end 34 and the lower end of the seating surface 33.

[0051] The seating surface is facing forwards in the intended rotation direction as indicated by the arrow 40. In this manner, as illustrated in FIGS. 7 and 8 the modular belt links 2 will be carried on the seating surface. As further illustrated in FIGS. 7 and 8 the periphery between adjacent drive teeth 12′ are provided with cut-outs in order to create larger openings between the conveyor belt 1 and the sprocket wheel 10 whereby easier cleaning may be achieved. In this particular embodiment illustrated in FIGS. 7 and 8 the drive teeth 12′ are further designed such that a top surface 37 is complementary to an under-surface 38 of the modular belt links 2.

[0052] This, however, is a special embodiment where the particular sprocket wheel 10 is specifically designed to the modular belt link 2. In other cases the modular belt modules will only be carried on seating surface as explained above.