Chain cover and slat conveyor using the same

A chain cover includes side covers each formed with a shaft hole for receiving a coupling pin of a roller chain, two top covers each having a length substantially equal to a chain pitch of the roller chain, and a coupling plate coupling the top covers adjacent to each other. The side cover at each end of the chain cover has a convexly arcuate front edge concentric with the shaft hole and a concavely arcuate rear edge similar to the front edge, and the coupling plate and two top covers cooperate to form a slat. A plurality of these chain covers can be mounted on a plurality of parallel roller chains to cover the top and sides of each roller chain and form a flat goods conveying surface between the roller chains, thereby forming a slat conveyor which is less expensive than a roller conveyor and provides excellent conveying stability.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates to chain covers mounted on a plurality of roller chains arranged in parallel so as to cover the top and sides of the roller chains and form a flat goods conveying surface between the roller chains, and a slat conveyor formed by the chain covers.

2. Background Art

A prior art chain cover of this type is disclosed in JP Patent laid-open publication 2001-315936. The chain cover shown in JP Patent laid-open publication 2001-315936 includes a top cover which is a flat plate having a length about equal to the chain pitch, and side covers hanging from both ends of the top cover. The side covers serve to cover both sides of the roller chain and each side cover is formed with a shaft hole in which one end of a coupling pin of the roller chain is received, a convexly arcuate front edge which is concentric with the shaft hole, a concavely arcuate rear edge which corresponds to the front edge, and a tapered guide surface which extends outwardly obliquely on the inner surface of the side cover below the shaft hole.

With this chain cover, the top cover for covering the top of a roller chain is supported by links of the roller chain, so that no load will be applied to each coupling pin, and such chain covers can be mounted on general-purpose roller chains on which the amount of protrusion of coupling pins from pin links is small, so that a flat conveying surface can be formed on the chains.

However, with such chain covers, a chain conveyor having a wide goods conveying surface cannot be formed, so that the application of the chain conveyor obtained is limited. Also, although the width of the goods conveying surface can be increased by extending both ends of the top covers sidewise, it is difficult to increase the width of the goods conveying surface drastically with this method because the length of the extended portion is limited to assure strength.

SUMMARY OF THE INVENTION

If a wide goods conveying surface can be formed by use of chain covers, a more inexpensive chain conveyor than a roller conveyor can be provided, so that it becomes possible to convey by an inexpensive chain conveyor goods which have heretofore been conveyed by a roller conveyor. Also, a chain conveyor formed by using chain covers can provide functionality which is not so different from the functionality of a known slat conveyor, and can provide improved conveying stability in comparison with the conveying by a roller conveyor.

An object of this invention is to provide a chain cover which meets such requirements and a slat conveyor formed by using such chain covers.

To solve the problem, according to the present invention, a chain cover is provided which comprises side covers each formed with a shaft hole to receive one end of each coupling pin of a roller chain, a number n (n≧2) of flat top covers arranged in parallel and each having a length substantially equal to the chain pitch of the roller chain, and a coupling plate for coupling the top covers together, wherein each side cover for covering the sides of the roller chain hangs from each end of the top cover for covering the top of the roller chain, the side cover at each end of the chain cover has a convexly arcuate front edge which is concentric to the shaft hole and a concavely arcuate rear edge which is similar to the front edge, and the coupling plate and a number n of the top covers cooperate to form a slat.

With this chain cover, preferably, the side cover at each end has a bottom surface which is straight and parallel to the top plate, and the distance from the center of the shaft hole to the straight bottom surface and the distance from the center of the shaft hole to the rear edge are both set to be about half the chain pitch; a reinforcing rib may be provided on the bottom of the coupling plate; the number n of the top covers, the side covers hanging from both ends of each top cover, the coupling plate between the top covers, and the reinforcing rib at bottom of the coupling plate may be made integrally of a resin.

Also, the top covers arranged at both ends may be provided with an extension protruding outwardly to increase the width of a goods conveying surface.

According to this invention, a conveyor is also provided in which the chain covers described above are combined with roller chains. The conveyor comprises a number n (n≧2) of endless roller chains arranged in parallel and each stretched around a driving sprocket and a driven sprocket, and the chain covers, the number of which corresponds to the number of pitches of each roller chain. The chain covers are those according to this invention and they are arranged in the same direction and mounted on the roller chains. When all the chain covers are mounted, the slat conveyor according to this invention is formed which has a flat goods conveying surface with slats of the chain covers continuous with one another in an endless fashion.

The chain cover according to the present invention is considered to be one which comprises a number n of chain covers (one disclosed in Patent Publication 1) each of which is opposed to one roller chain, arranged in parallel and coupled together by a coupling plate which is continuous with top covers. The number n of the top plates arranged in parallel and the coupling plates between the top covers form a wider slat (in comparison with the chain cover of Patent document 1) and produce a goods conveying surface of a width not inferior in comparison with a roller conveyor.

The chain cover can be provided at low cost if it is made of a resin by integral molding. By combining with a number n of roller chains, a more inexpensive slat conveyor than a roller conveyor can be formed. A slat conveyor can provide higher conveying stability than a roller conveyor because it has a flat conveying surface, so that goods protection can be assured.

Also, it is possible to change the width of goods conveying surface freely by changing the number n of chains and top plates used, thereby solving the problem of limited application of conveyors.

DETAILED DESCRIPTION OF THE INVENTION

Hereinbelow, embodiments of this invention are described with reference to the accompanying drawingsFIGS. 1 to 6. Chain covers1shown inFIG. 1are combined with two endless roller chains arranged in parallel to form a slat conveyor. Each chain cover1includes as many top covers2as there are chains, side covers3hanging down from both ends of each top cover2, and a coupling plate4coupling the top covers2together. The chain cover1shown here is made integrally of a resin by injection molding and can be made at low cost. But it may be a metal casting.

The length L of each top cover2is substantially equal to a chain pitch P (seeFIG. 2). The width W1of each top cover2is of a size proportional to one roller chain. Particularly, as shown inFIG. 3, the width W1is set to be substantially equal to the width w of each roller chain21covered by the top cover2plus the thicknesses of the side covers3at both ends of the top cover.

Each side cover3has a shaft hole5for receiving one end of a coupling pin22of the roller chain21, and a tapered guide surface6for easy mounting of the coupling pin22into the shaft holes5. Also, the side covers3at both ends of the chain cover1are each formed with a convexly arcuate front edge7which is concentric with the shaft hole5, and a concavely arcuate rear edge8which corresponds in shape to the front edge7. Here, for convenience of explanation, the convex edge7is referred to as a front edge and the concave edge8is referred to as a rear edge, but actually they have no relation of front and rear to each other.

The side covers3arranged inside have a simplified shape with only a portion formed with the shaft hole5left for saving of material and easy molding, but they may be made to the same shape as the side covers3at both ends of the chain cover. Also, the shaft holes5may be through holes or not-through holes.

As shown inFIG. 3, the height H of the side covers3at both ends is substantially equal to the height of the roller chains21. Also, the bottom surfaces9of the side covers3at both ends are straight surfaces that are parallel to the top covers2and the height h from the center of each shaft hole5to the bottom surface9is substantially equal to half of the chain pitch P. Further, an acute corner portion formed at the intersection of the rear edge8and the bottom surface9is removed and a distance from the center of the bottom surface9to the rear edge8is set to be substantially equal to half the chain pitch P. By meeting these requirements, the effect of preventing the chain cover1from coming off increases.

Further, each side cover3is formed with a raised portion10of a small area on its inner surface around the shaft hole5and the distance between the raised portions10of the opposed side covers3is set to be substantially equal to the distance between the opposed pin links23of the chain, so that the raised portions10narrow the area on which the opposed side covers3are in contact with the roller chain21. Also, between the side covers3at both ends, an auxiliary cover11is provided which extends forwardly of the top covers2. The auxiliary cover11is a preferable element which serves to fill a gap formed between the chain covers at turning points where the chain21turns.

The coupling plate4is continuous with the top plates2on both sides. The coupling plate4and the top plates2cooperate to form a slat having a flat upper surface having a length L and a width W. If the chain covers shown here are adopted, the width of their slats is the required width of the conveyor. The width of the slats is adjusted by changing the distance between the top plates2. The larger the width of the coupling plate4(that is, the distance between the top plates), the more remarkably the coupling plate tends to flex. Therefore, if flexing due to large width is feared, the coupling plate4should be provided with a reinforcing rib12at its bottom. With the chain cover of this embodiment, two reinforcing ribs12are provided, but the number of reinforcing ribs is not limited. If a reinforcing rib12is provided, the coupling plate4may be thin, so that the material cost can be reduced.

With the chain covers1of a structure described above, as shown inFIG. 2, a plurality of chain covers1of the same specification are arranged in the same direction for two lines of roller chains21arranged in parallel (only one line is shown) and are mounted so that one chain cover1engages one coupling pin. The mounting work is done by pressing each side of the chain cover1on one chain21and pushing the cover1downward or obliquely downward. When the chain cover1is pushed down, a component force acting on the contact points between the tapered guide surfaces6and the coupling pins22elastically deforms the side covers3and pushes them wide, so that both ends of each coupling pin22will be received in the opposed shaft holes5and the side covers3will restore elastically and maintain engagement with the coupling pins22.

FIG. 2shows the side of the roller chain with the chain covers1mounted. In this state, as shown inFIG. 3, the top covers2are supported on roller links24of the chains, so that the coupling pins22will not be under heavy loads.

FIG. 4shows a slat conveyor formed by use of the chain covers1shown inFIGS. 1 to 3. The slat conveyor25comprises two endless roller chains21arranged in parallel, two driving sprockets26and two driven sprockets27, each roller chain21being trained around one driving sprocket26and one driven sprocket27, and as many chain covers1as the pitches being mounted over the entire range of each roller chain21. When all the chain covers1have been mounted, slats each formed by the top plates2and the coupling plate4of each cover1continue in an endless fashion, thus forming a slat conveyor having a flat goods conveying surface. Each driving sprocket26is provided with a driving source (not shown) such as a geared motor and is driven thereby.

Depending on the width requirement for the conveyor, more than two roller chains21can be provided.FIG. 5shows a chain cover of an embodiment used when three roller chains are installed. This chain cover1A includes three chain covers arranged in parallel, each of the chain covers having a top plate2and two side covers3hanging from both ends of the top plate2, and coupling plates4each coupling the adjacent chain covers together. Among the side covers3, ones arranged at both ends are provided with a convex front edge and a concave rear edge, but other side covers may not be provided with arcuate front or rear edges because they are invisible from outside.

The chain cover according to this invention may be combined with four or more roller chains. Also, as shown inFIG. 6as a chain cover1B, the chain cover may have extensions13extending outwardly from the top plates2at both ends to increase the width of the goods conveying surface of the conveyor.