Chain guide for paddle-type conveyor

Abstract

A guide that fits over a paddle link in a paddle-type elevator in a harvester combine grain elevator. The plastic guide provides a wide, low-friction surface that rides on the intermediate wall of a grain elevator, thereby keeping the paddle links from rubbing against and causing wear to the intermediate wall. The guide also serves to inhibit the paddle from tipping back, thereby preventing the concentration of force by one corner of a paddle link against the intermediate wall. The guide also helps maintain the correct orientation of flexible paddle against the inside of the elevator housing, thereby inhibiting the paddle from tipping back and leaking grain back into the upward path of the conveyor. The plastic guide also reduces noise caused by the metal parts of a paddle-type elevator from coming into contact.

Description

CHAIN GUIDE FOR PADDLE-TYPE CONVEYOR FIELD OF THE INVENTION The present invention relates to a chain guide. More specifically, the invention relates to a chain guide for a paddle-type conveyor in a combine harvester. BACKGROUND OF THE INVENTION A harvester combine may be used to harvest crops, such as wheat. Such combines often have a header at the front for reaping the crop and collecting it into a feederhouse where it is carried to a thresher within the combine. The thresher separates grain and chaff from straw then directs the partially clean grain to a shoe, where chaffer and sieves further separate the chaff from the grain. The straw and the chaff are discharged out the back of the combine and the clean grain is collected at the bottom of a grain elevator. In some implementations, the grain elevator may be a paddle-type, endless-chain conveyor that lifts the grain on paddles upward to an auger which in turn moves and discharges the grain into a hopper. Such paddle-type grain elevators are be formed by an elongated rectangular housing. The bottom of the housing is located near the lower area of the combine where the clean grain is received from the chaffer and sieves. The top of the housing is located near the upper part of the combine where grain is poured into the auger and then to the hopper. Between the bottom and the top of the housing is an endless link chain which rides within the housing between a bottom sprocket near the bottom of the elevator and a top sprocket near the top of the elevator. Between the bottom sprocket and the top sprocket, and separating the chain, is an intermediate wall that divides the housing into two mostly vertical chambers. Incorporated into the links of the chain are the paddles that scoop up grain from the bottom of the elevator and raise the grain between the intermediate wall and an inner wall of the housing to the top of the elevator, where the grain is flung or falls down from the paddle through the elevator outlet to the auger, which discharges the crop into the hopper. The paddles are typically formed of layers of flexible material (e.g., rubber and cord) and such flexible paddles typically form a seal between the intermediate wall and the other inner surfaces (e.g., inner wall) of the housing. The flexible paddles are incorporated into the endless chain via a paddle link. The paddle link has a paddle support to which the flexible paddle is secured by a fastener. A gap in the paddle allows the chain to pass through. However, a problem with such paddle-type elevators is that, as the flexible paddles scoop up grain, the weight of the grain, as well as friction between outer edge of the flexible paddle and the inner surfaces of the housing, can cause the outer edge of the flexible paddle to flex backward, which in turn causes the paddle link to swivel back and rub against the intermediate wall. When the paddle link swivels back under load, the force exerted by one corner of the paddle link against the intermediate wall may be concentrated, which may cause premature wear to the intermediate wall and the paddle link. When the wear to the intermediate wall is too great, or the wear creates gaps, holes, or tears in the intermediate wall, the only option is to replace the entire elevator, which is an expensive and time consuming repair. Further, as this wear tends to occur during the peak of harvesting, the expense and delay of repair can cause significant losses to the farmer. What is needed is a solution to the problem of such wear to a paddle-type elevator. SUMMARY OF THE INVENTION The present invention is a plastic guide that fits over a paddle link in an endless roller chain, The chain guide of the present invention is well suited for use in a paddle-type elevator, such as in a combine. The plastic guide provides a wide, low-friction surface that rides on the intermediate wall of an elevator, thereby keeping the steel paddle link from rubbing against and causing wear to the intermediate wall. The guide also serves to inhibit the paddle from tipping back, thereby preventing the concentration of force at one corner of a paddle link against the intermediate wall. The guide also helps maintain the correct orientation of flexible paddle against the inside of the elevator housing, thereby inhibiting the paddle from tipping back and leaking grain back into the upward path of the conveyor. The plastic guide also reduces noise caused by the metal parts of a paddle-type elevator from coming into contact. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side view of a conventional combine harvester with a side conveyor. Figure 2 is a partial cut-away, side view of the bottom and upper portions of a conventional paddle-type conveyor. Figure 3 is a three-quarter, perspective view of a conventional conveyor chain with paddles mounted to it. Figure 4A is a partial side view of a conveyor chain paddle link with the paddle shown in broken lines. Figure 4B is a partial top view of a conveyor chain paddle link without a paddle. Figure 5 is a partial cut-away, side view of the upper portion of a conventional paddle-type conveyor in operation. Figure 6 is a partial cut-away, side view of the upper portion of a paddle-type conveyor with the chain guide of the present invention. Figure 7 is a three-quarter perspective view of the chain guide of the present invention, shown from the bottom rear. Figure 8A is a bottom view of the chain guide of the present invention. Figure 8B is a side view of the chain guide of the present invention. Figure 8C is a rear view of the chain guide of the present invention. Figure 8D is a front view of the chain guide of the present invention. Figure 8E is a top view of the chain guide of the present invention. Figure 9 is a three-quarter perspective view of the guide of the present invention mounted on a paddle link, shown from the top rear. Figure 10 is a side view of a conventional paddle link under load. Figure 11 is a side view of the guide of the present invention mounted on a paddle link. DETAILED DESCRIPTION Referring to Figure 1, a harvester combine 10 is used to harvest crops, such as wheat. The harvester combine 10 has a header 11 at the front for reaping the crop and collecting it into a feederhouse 12 where it is carried to a thresher 13 within the harvester combine 10. The thresher 13 separates grain and chaff in the crop from straw in the crop then directs the partially clean grain to the shoe, where chaffer and sieves 14 further winnow the chaff from the grain. The straw and the chaff are discharged out the back 19 of the harvester combine 10 and the clean grain is collected at the bottom of a grain elevator 15. In the implementation shown, the grain elevator 15 is a paddle-type, endless-chain conveyor that lifts the grain 30 on paddles 29 (shown in Figure 2) upward to an auger 16 which in turn moves and discharges 17 the grain into a hopper 18. Referring now to Figures 2 through 4, the paddle-type elevator 15 is formed by, and is enclosed by, a substantially vertical, elongated rectangular housing 21. A bottom 22 of the housing 21 is located near the lower area of the harvester combine 10 where the clean grain is received from the chaffer and sieves 14 (shown in Figure 1). A top 23 of the housing 21 is located near the upper part of the harvester combine 10 where the grain is poured into the auger 16 and then to the hopper 18 (also shown in Figure 1). Between the bottom 22 and top 23 of the elevator 15 is an endless link chain 27 which rides within the housing 21 between a bottom sprocket 25 near the bottom 22 of the elevator 15 and a top sprocket 26 near the top 23 of the elevator 15. One of the bottom or top sprockets 25 or 26 drives the chain 27. Between the bottom and top sprockets 26 and 25, and separating the chain 27, is an intermediate wall 28 that divides the elevator housing 21 into two substantially vertical chambers, an upward chamber 40a and an return chamber 40b. Incorporated into the links of the chain 27 are the paddles 29. The clean grain 30 is received at the bottom 22 of the elevator 15, where the paddles 29 scoop up the grain 30 and carry it within the upward chamber 40a to the top 23 of the elevator 15. As the paddles 29 ride over the top sprocket 26, the paddles 29 arc through a vertical position to a downward facing horizontal position, during which the grain 30 is flung or dropped downward and out an outlet 24 of the elevator 15 to the auger 16 which transfers the grain 30 to the hopper 18 (shown in Figure 1). The chain 27 with the empty paddles 29 then continues down the return chamber 40b and the process continues. Figures 3 through 4B show how the flexible paddles 29 are incorporated into the chain 27. The flexible paddles 29 are held by paddle links 35 incorporated as links in the endless chain 27. The paddle link 35 has a paddle support 36 to which the paddles 29 are fixed or secured by a fastener 34. A gap 39 in the paddles 29 allows the chain 27 to pass through. The paddles 29 are generally constructed from layers of flexible materials, such as rubber and cord. Such flexible paddles 29 are adapted to form a seal between the intermediate wall 28 and the three inner walls of the elevator housing 21, sufficient to prevent the grain 30 from leaking back down into the upward chamber 40a. These paddle links 35 are usually formed as outer links 31 of the chain 27, such as outer plates of the outer links 31 as shown in Figure 3 and 4B. At each longitudinal end of the paddle link 35 is a bore for a link pin 37, which corresponds with an axial roller bore in an inner link 32 of the chain 27, thereby joining the paddle link 35 into the chain 27. Separating inner plates of inner link 32 of the chain 27 are roller bushings 38 aligned about the axis of the pin 37. The roller bushings 38 allow low friction movement of the chain 27 around the top and bottom sprockets 25 and 26. The pins 37 are riveted in place, on either side of the paddle link 35 or the outer link 31 to hold the inner link 32 in place, yet allow rotational movement about the pin 37. In conventional combine elevator 15 chains 27, the steel side plates of the paddle links 35, the outer links 31, and the inner links 32, are typically about 2-1 / 2 inches long and about 1 / 8 inch thick. As described above and shown in Figures 5 and 10, conventional paddle-type elevator chains are prone to wear, because the paddle links 35 swivel back about the rearmost pin 37 owing to the friction on the outside edges of the paddle 29 against the inner surfaces of the housing 21 and the weight of the grain 30 causing the outside edges of the paddle 29 to flex backwards, as shown at 41 in Figures 5 and 10. This swiveling force causes a rearmost edge of the paddle link 35 to rub against the intermediate wall 28, shown by arrow 42 in Figures 5 and 10, resulting in wear to the intermediate wall 28 and premature failure of the elevator housing 21. To solve this issue, some embodiments of the elevator 15 may include a guide 43, as shown in Figures 6 through 9 and 11, that fits over the paddle link 35 and distributes the forces acting against the paddle 29 through skids 54 of the guide 43, which slide on the surface of the intermediate wall 28. In addition to distributing the load over the skids 54, the guide 43 runs closer to the intermediate wall 28 than the chain 27, thereby allowing less slack in the chain 27 and inhibiting the paddle link 35 from swiveling back. Also, the space 49 in the guide 43 for the inner link 32 to pass has a top wall 55 that forms a stop to prevent the forward end of the inner link 32 from swiveling upward and allowing the paddle link 35 to swivel back (as at 42 in Figures 5 and 10); yet, when the forward inner link 32 and paddle link 35 pass over one of the bottom or top sprockets 25 or 26, the space 49 allows the rearward ends of the inner and paddle links 32 and 35 to swivel and travel around the bottom or top sprocket 25 or 26. In the disclosed embodiment, the guide 43 is generally rectangular, with a height A (from the skids 54 on a bottom 44 of the guide 43 to the top 48 of the guide 43) of about 1-1 / 2 inches, a width B (between sides 46 of the guide 43) of 2-1 / 4 inches, and a length C (from a front 45 of the guide to a back 47 of the guide 43) of about 2 inches. The space 49 for the inner link 32 has a width H of about 1-1 / 16 inches, which accommodates a conventional inner link 32 with a width of about 1 inch. The inner link space 49 of the guide 43 extends backward from the chain's 27 direction of travel by a length F of about 3 / 4 inch. The inner link space 49 has a height G of about 1 inch, a little more than the 13 / 16 inch height of a conventional chain link. The height G of inner link space 49 allows the skids 54 of the guide 43 to extend about 3 / 16 inch below the bottom edge of the inner link 32 and the paddle link 35, and allows some space above the top edge of the inner link 32 for upward rotation, yet forms a stop 55 to prevent further upward rotation of the inner link 32. The stop 55 helps to inhibit the paddle link 35 from swivelling back. The space 50 for the paddle link 35 has a width J of 1-3 / 8 inches, which provides a close friction fit with a conventional outer link 31 which, like the paddle link 35, has a width J of 1-3 / 8 inches. A step 51 in from the inner link space 49 to the paddle link space 50 aligns with and butts against the leading edge of the paddle support 36. The step 51 has a width I of about 1 / 8 inch, corresponding to the width of a conventional chain link plate. The tight fit between the paddle link space 50 and the paddle link 35 itself, as well as the alignment of the step 51 with the leading edge of the paddle support 36 inhibits rotation of the guide 43 and holds the guide 43, with the paddle link 35, in the direction of the chain's 27 travel. The paddle link space 50 extends forward to the direction of travel by a length K of about 1-1 / 4 inch. A bore 52 is sized to receive the head of a pin's 37 rivet on the outside of the paddle link 35 and thereby hold the guide 43 in place. Such pins 37 commonly have riveted heads of about 1 / 4 inch in diameter, so a suitable bore (or, an indent in the guide's paddle link inner side wall 53) would be 1 / 4 to 5 / 16 inch. The length K of the paddle link space 50 is about half the length of a conventional 2-1 / 2 inch chain link, which covers the rear edges of the paddle link 35 from the direction of the chain's 27 travel. Thus, the guide's 43 skids 54 extend 2 inches in the direction of the chain's 27 travel, from the trailing inner link's 32 mid section to the midway point of the paddle link 35. The skids 54 of guide 43 are wide enough to provide a surface that will slide on the intermediate wall 28 without excessive friction and provide stability to the paddle 29. In the disclosed embodiment, the skids 54 have a width D of 5 / 8 inch on either side of the trailing inner link 32 and a width E of 7 / 16 inch on either side of the paddle link 35. Comparing the skid widths D and E to the 1 / 8 inch width of a convention chain link, gives a ratio of 5:1 for the skid width D compared to the trailing inner link's 32 edge, and a ratio of 3.5:1 for the skid width E compared to the paddle link's 35 edge. The guide 43 is preferably made of a plastic material, such as nylon or polyester, which are easy and cheap to produce, by molding, for example, provide low friction against the steel intermediate wall 28, and are strong and durable. Silicone impregnated nylon has been found to work well. The drawings and description set forth here represent only some embodiments of the invention. After considering these, skilled persons will understand that there are many ways to make a harvester combine elevator chain guide according to the principles disclosed. The inventor contemplates that the use of alternative structures, materials, or manufacturing techniques, which result in a chain guide according to the principles disclosed, will be within the scope of the invention.

Claims

1. A grain elevator chain guide comprising: an endless roller chain comprising: inner links formed by inner side plates having front and rear inner plate ends and held apart from each other in a spaced relationship by rollers located at each of the rear and front inner plate ends, each roller having an axial bushing bore; and outer links formed by outer side plates having front and rear outer plate ends and openings in each of the front and rear outer plate ends, wherein the opening of the front outer plate end is aligned with and rotatably connected with the axial bushing bore of the rear inner plate end of one of the inner links by one of a plurality of link pins, and the opening of the rear outer plate and is aligned with and rotatably connected with the axial bushing bore of the front inner plate end of another of the inner links by another of the link pins; at least one paddle link formed as part of one of the outer links, the at least one paddle link comprising at least one paddle support extending out from the outer link generally tangential to a direction of travel of the endless roller chain; a paddle attached to the at least one paddle support; and a chain guide having a front, a rear opposite the front, oppositely disposed first and second sides, a top, a bottom opposite the top, a low friction guide surface formed in the bottom, wherein the chain guide further comprises: a paddle link space between the first and second sides and open at the front and the bottom and the rear, wherein the paddle link space is sized to accommodate side plates of the at least one paddle link within the paddle link space; and an inner link space between the first and second sides, open at the rear and the bottom, and forming a ceiling above the inner link space and below the top of the chain guide, wherein the inner link space is defined to accommodate the inner side plates of the inner link within the inner link space without preventing the inner link from rotating about the link pins, and wherein the ceiling stops rotation of the inner link in one direction.

2. The grain elevator chain guide of claim 1 wherein the paddle link space further comprises a top opening in a portion of the top of the chain guide sized to allow the at least one paddle support to pass through.

3. The grain elevator chain guide of claim 1 further comprising rivet spaces in inner walls of the first and second sides of the paddle link space, wherein the rivet spaces are aligned with heads at each end of the link pins.

4. The grain elevator chain guide of any one of claims 1-3 wherein the paddle link space is sized to form a close friction fit over the at least one paddle link.

5. The grain elevator chain guide of any one of claims 1-3 wherein the chain guide is constructed of plastic.

6. The grain elevator chain guide of claim 5 wherein the plastic is low friction.

7. The grain elevator chain guide of claim 5 or 6 wherein the plastic is silicone impregnated nylon.

8. The grain elevator chain guide of any one of claims 1-7 wherein the low friction guide surface is formed in the bottom of the chain guide on either side of bottom edges of the inner side plates and paddle link side plates of the at least one paddle link.

9. The grain elevator chain guide of claim 8 wherein the low friction guide surface has skid width of at least twice a thickness of the inner side plates of the inner links.

10. The grain elevator chain guide of claim 8 or 9 wherein the low friction guide surface has a skid width of at least three-eighths of an inch.

11. A chain guide for a continuous roller chain operating in a loop, the continuous roller chain having outer and inner links alternately coupled along a chain drive direction, wherein the outer link comprises a pair of oppositely disposed outer side plates, each outer side plate having a first end and a second end opposite the first end, the first and second ends of the outer side plates oriented along the chain drive direction, an outer side plate length from the first to the second end, an outer side plate thickness, an outer side plate edge extending around a perimeter of the outer side plates, a top edge extending along the outer side plate length outside the continuous roller chain, a bottom edge extending along the outer side plate length inside the continuous roller chain, an outer side plate height from the bottom edge to the top edge and normal to the outer side plate length, lateral pin bores adjacent the first and second ends, wherein the pin bores are aligned with axial roller bores of the inner link, wherein the chain guide comprises: a body having a length, width, height, and bottom, the body further comprising an internal space sized to engage and fit around at least a portion of the outer side plates of the outer link, wherein the bottom of the chain guide extends beyond the bottom edge of the outer side plates and forms a skid surface along the bottom of the chain guide.

12. The chain guide of claim 11 wherein the skid surface of the chain guide has a lateral skid width greater than the outer side plate thickness.

13. The chain guide of claim 12 wherein the lateral skid width is at least three times greater than the outer side plate thickness.

14. The chain guide of any one of claims 11-13 wherein the skid surface of the chain guide is constructed of a low fiction plastic material.

15. The chain guide of any one of claims 11-14 further wherein the continuous roller chain further comprises at least one paddle link formed as part of the outer link, and wherein the internal space of the chain guide is further sized to fit around the at least one paddle link.

16. The chain guide of any one of claims 11-15 wherein the chain guide is formed of a silicone impregnated nylon material.