GB2309062A

GB2309062A - A chain link conveyor belt having unsymmetrical hinge parts

Info

Publication number: GB2309062A
Application number: GB9602341A
Authority: GB
Inventors: Poul Erik Damkjaer
Original assignee: BAELTIX MASKINFABRIKKEN AS
Current assignee: BAELTIX MASKINFABRIKKEN AS
Priority date: 1996-02-06
Filing date: 1996-02-06
Publication date: 1997-07-16
Anticipated expiration: 2016-02-06
Also published as: GB9602341D0; GB2309062B; GB2309062A8

Abstract

A chain link conveyor belt comprises a top plate 6 attached to hinge parts 3 which are unsymmetrical in relation to centre line 5' of hinge pins 5 to the effect that L, the side facing the centre axis 13 of the chain link, is greater than 1. When the chain links are assembled their unsymmetrical form results in a notch 23 which acts as a guide for teeth 10 of sprocket wheel 9. Extensions 11 have a tapered form 14 ending in a reduced front edge 19 which automatically centres the belt on sprocket 9. The chain links may be injection moulded in a thermoplastic material and provided with through openings 8 for drainage, cooling air or other purposes. In order to reduce friction between the chain links and support 20 a support bar 22, having an inclined or conical surface 18, is provided.

Description

"Chain Link Conveyor" Background of the Invention The invention relates to a chain link conveyor composed of a number of chain links and as further described in the preamble of claim 1.

Such chain link conveyors are often configured as so-called conveyor belts, i.e. straight-running conveyors, where the chain links form a belt to be drawn by a number of sprocket wheels. The known conveyor belts are driven forward either by the teeth of the sprocket wheels being arranged to engage with downward-facing parts between the hinges, for example as described in USA patent no. 4,688,670, or by the teeth of the sprocket wheel engaging with the hinge construction, as the individual chain links are provided with bars moulded in one piece with the hinge parts on both sides of each chain link, for example as described in ap plicant's own USA patents nos. 5,000,312 and 5,305,869 or as described in USA patent no. 4,438,838, where the bars control the engagement of the sprocket wheel.

The first mentioned method does not provide automatic control of the sideways displacement of the belt in relation to the sprocket wheel, and the latter method has the effect that the underside becomes very difficult to clean. Therefore, it is difficult to obtain official approval of conveyor belts of this type for the transport of food articles.

Advantages of the Invention By configuring a chain link conveyor according to the invention as disclosed in the characterizing part of claim 1, a number of advantages is obtained. The most essential advantage. is that the hinge links can be used as a point of engagement for the teeth of the sprocket wheel. At the same time control of the sideways displacement of the belt and the sprocket wheel is obtained automatically.

By configuring the chain link conveyor according to the invention as disclosed in the characterizing parts of claims 2-8, a number of additional advantages is obtained.

The possibility is provided of configuring the chain links with a completely plane and smooth underside which in turn ensures a safe and thorough cleaning. In addition, the top plate can be configured with any thickness as desired for specific purposes.

In many embodiments it is necessary to provide holes or openings in the top plate for draining or for blowing through of for example cooling air. With the invention the configuration and position of the holes as well as their shape and size are optional, as no ribs are needed on the underside.

The special configuration of the hinge eyes according to the invention allows the sprocket wheel to engage, which ensures that the conveyor operates in an even and safe manner.

On the other hand, there is no reason why reinforcement ribs could not be provided on the underside if the chain link conveyor must be able to withstand a stronger traction force than can be obtained via the top plate alone.

The new configuration of the hinge parts according to the invention is particularly suitable for conveyor belts, for example for the conveyor belts which will be explained in the description below. However, nothing prevents the new configuration of the hinge eyes from being used for other types of chain link conveyors where it is desirable to obtain the above advantages.

The Drawing An embodiment of the invention will be explained in further detail below with reference to the drawing, wherein fig. 1 shows a number of hinged-together chain links according to the invention seen from the bottom, fig. 2 shows a chain link according to the invention seen in the direction II-II in fig. 1, fig. 3 shows a number of chain links as in fig. 1 but seen from the side and in engagement with a sprocket wheel for driving the belt forwards, fig. 4a shows a chain link as in the previous figures but seen from the top, fig. 4b shows a chain link as in fig. 4a but in a second embodiment, and fig. 4c shows a chain link as in figs. 4a or 4b but in a third embodiment.

Description of the Embodiment Examples In the drawing 1 is a chain link with eye-shaped hinge parts 3 along the front edge and the rear edge. The hinge parts are displaced so that they can be coupled together in a generally known manner, as shown in figs. 1 and 3, to form a chain link conveyor or a chain link belt. Fig. 1 shows three identical chain links 1. However, in practice chain links with modular dimensions having varying widths will be used for wider belts so that the belt can be assembled by means of chain links being mutually offset in the direction of travel, for example as shown in fig. 1 in the above USA patent no. 4,688,670. The chain links are hinged together in a known manner via through-bores 4 in the hinge parts 3 by means of cylindrical pins or axles 5 as shown by a centre line 5'.

In the example illustrated the direction of travel is shown by the arrow 2, but as the individual chain links 1 are symmetrical around a central or symmetrical point 17, the direction of travel might as well be the opposite direction. There is usually no preferred direction of travel for the chain links.

In addition to the hinge parts 3 a chain link according to the example shown comprises a top plate 6 which is plane and smooth both on the top side 6' as well as on the underside 7.

Between the hinge parts 3 the top plate ends in an inclined cut or edge 12 so that the chain links can be assembled as shown. Depending on the application of the conveyor the chain links 1 can have a solid top plate, see figs. 1 or 4a, or a top plate with through-going openings 8 for draining, cooling air or other purposes, see figs. 4b and 4c.

The size of the openings 8 depends on the application of the conveyor, and the plane top plate without ribs on the underside renders almost any configuration and position of the through-going openings 8 possible. The thickness of the top plate 6 may also be varied depending on the field of application.

Chain links of this type are moulded in a generally known manner as a unit in one piece of a suitable plastic material, preferably by injection moulding of a thermoplastic material.. Belt or chain link conveyors of this type are operated in a generally known manner and as shown in fig. 3 by motordriven sprocket wheels 9 with teeth 10 for engagement with the underside of the conveyor.

In conveyor belts as shown and according to the invention the hinge parts 3 are configured in a special manner. As shown in figs. 1 and 3 they are configured unsymmetrically in relation to the centre line 5' of the hinge pins to the effect that they have the largest thickness on the side facing the centre of the chain link as shown by the centre axis 13. The result is a notch 23 between the hinge parts when the chain links are assembled, see figs. 1 and 3.

These notches 23 can be used as guides for the teeth 10 of the sprocket wheels which engage the chain link forcibly at the point or surface of traction 16, see fig. 1, where the positions of the teeth 10 of two sprocket wheels are shown by a broken line.

The point or surface of traction 16 is present in any of the resulting notches 23 across the width of the belt.

Accordingly, the notches 23 are positioned between the extensions 11 on each hinge eye 3. The size of the hinge eye 3 seen in the horizontal plane of the chain link is shown by the measures 1 and L which can be 9 mm and 13 mm, respectively, in the example in question. The length L is in the order of 30-558 larger than 1 in case of ordinary chain links, whereas in case of special chain links it can have other dimensions.

The hinge parts 3 of such chain links can be in driving engagement with the driving wheels and the sides 15 of the hinge parts simultaneously and constitute a guide for the belt in respect of the sideways displacement.

By tapering 14 the extensions 11 of the hinge eyes as shown in fig. 1, thereby reducing the width of the front edges 19, the belt is automatically centered on the sprocket wheels.

Additional improvements and advantages can be achieved by providing the downward-facing parts of the hinge parts with an inclined surface 18 on each side, said surface being suitably arched or conical, as shown in fig. 1. The hinge parts will hereby allow the sprocket wheels to engage.

Fig. 1 shows that the underside 20 of the hinge parts 3, which underside constitutes a sliding surface for a support or a slide bar 22 or the like, see fig. 3, has reduced width in the centre area because of the inclined or conical surfaces 18. The friction between the chain links and the support 22 is hereby reduced.

In addition to the above advantages the chain links according to the invention are also advantageous productionwise, as they require less material and the moulding process is simplified and reduced compared to the known chain links of the same type.

The chain links shown in the drawing are examples only of how chain links according to the invention can be configured. Many other configurations could be imagined within the scope of the below patent claims.

Claims

1. Chain link conveyor composed of a number of plastic chain links (1) each having a top surface (6) arranged to support the items to be transported and where each chain link has a number of eye-shaped hinge parts (3) in the edge of opposite sides in the direction of travel, each hinge part (3) having a transverse hole (4) for coupling with corresponding hinge parts (3) of adjacent chain links by means of a pin or an axle (5), the hinge parts on the opposite sides of each chain link being offset in relation to each other, c h a r a c t e r i z e d in that at least one hinge part (3) is arranged to engage with a sprocket wheel (9, 10) for driving the conveyor forward, and that at least one hinge part (3) is unsymmetrical in relation to the centre axis (5') of the transverse hole (4) so that the hinge part has the largest thickness (11) on the side facing the centre (13) of the chain link.

2. Chain link conveyor according to claim 1, c h a r a c t e r i z e d in that the side of the hinge part having the largest thickness (11) is tapered (14) towards its front edge (19) so that the width of the front edge (19) is reduced in relation to the central area of the hinge part.

3. Chain link conveyor according to claim 1, c h a r a c t e r i z e d in that the side of the hinge part having the largest thickness (11) has an inclined surface (18) on the side which is adapted to face a sprocket wheel (9, 10).

4. Chain link conveyor according to claim 3, c h a r a c t e r i z e d in that the inclined surface (18) is arched or conical.

5. Chain link conveyor according to claim 1, c h a r a c t e r i z e d in that the extension of the side (17) of the hinge part having the largest thickness is 30-55t larger in the direction towards the centre (L) of the chain link as compared to the extension (1) in the opposite direction.

6. Chain link conveyor according to any of the claims 1-5, c h a r a c t e r i z e d in that each chain link (1) is formed symmetrical around a central point (17).

7. Chain link conveyor according to claim 6, c h a r a c t e r i z e d in that the width of the downward-facing side (20) of the hinge parts (3) is reduced.

8. Chain link conveyor according to claim 7, c h a r a c t e r i z e d in that the width is reduced to be smallest in the area (21) which is adapted to slide against an underlying support (22), for example a slide bar or the like.

9. A chain link conveyor substantially as hereinbefore described with reference to the accompanying drawings.

9. Chain link conveyor substantially as hereinbefore described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows 1. A chain link conveyor composed of a number of plastic chain links each having a top surface arranged to support items to be transported and where each link has a number of eye-shaped hinge parts along forward and rearward edges of the link in the direction of travel, the hinge parts having transverse holes for coupling to corresponding hinge parts of adjacent links by means of a connecting pin, the hinge parts along the opposite edges of each link being offset in relation to each other so that at least one hinge part has a first extension defining a rear edge situated at a first distance from the central axis of the transverse hole of the hinge part and facing away from the centre of the link, and a second opposite extension defining a front edge situated at a second distance from the central axis and facing towards the centre of the link, whereby the extensions are engageable by a sprocket wheel for driving the conveyor, wherein the second distance is larger than the first distance such that a notch is provided between neighbouring hinge parts of successive links for engagement by the teeth of the sprocket wheel.

2. A chain link conveyor according to claim 1 wherein the second extension of the hinge part is tapered towards its front edge so that the width of the front edge is reduced in relation to the central area of the hinge part.

3. A chain link conveyor according to claim 1 or 2, wherein the side of the hinge part has an inclined surface adapted to face a sprocket wheel.

4. - A chain link conveyor according to claim 3, wherein the inclined surface is arched or conical.

5. A chain link conveyor according to claim 1, 2 or 3 wherein the second distance is 30 - 55% larger than the first distance.

6. A chain link conveyor according to any preceding claim, wherein each chain link is formed symmetrically about a central line.

7. A chain link conveyor according to claim 6, wherein the width of the downwardly facing side of the hinge parts is reduced.

8. A chain link conveyor according to claim 7, wherein the width is reduced to be smallest in the area which is adapted to slide against an underlying support.