US2487500A - Conveyer chain - Google Patents

Description

GONVEYER CHAIN Filed Oct. 22, 1943 Nov. 8, 1949 J. B. WEBB 2,487,500

Patented Nov. 8, 1949 CONVEYER CHAIN Jervis B. Webb, Bloomfield Hills, Mich., assignor,

by mesne assignments, to Jervis B. Webb Company, Detroit, Mich., a corporation of Michigan Application October 22, 1943, Serial No. 507,278

This invention relatesto a particular type of chain variously called keystone, rivetless or Weston chain which, for many years, has had wide application in conveyors, mining machinery and other industrial uses.

The original rivetless chain which was the subject matter of Weston Patent No. 870,704, consists of a plurality of center links and side bars, as they are termed in the art. Each center link consists of an integral piece of metal having a pair of laterally spaced side walls joined at their ends by curved end walls, said side and end walls enclosing or surrounding an elongated slot. A pair of side bars each having an elongated slot at each end is pivotally connected to each end of each center link by headed pins, each pin having a transverse head on each end thereof similar to the headed end of a T-head machine bolt. The side bars are formed at their ends with transversely extending recesses on their outer faces in which the heads of the pins are seated to lock the pins in position after the center links and side bars have been coupled together. Each of the center links has a narrowed central portion which tapers outwardly adjacent to the ends of the link to form thickened portions at the link ends. The center links and side bars are assembled by holding the elongated slots in the ends of a pair of side bars one on each side of the center link at the central portion of the elongated slot of the center link and in parallelism therewith, then inserting the headed end at one end of a headed pin through thethree slots, next turning the side bars at a right angle to the center link and seating the heads of the pins in the trans: verse slots at the ends of the side bars, after which the pair of side bars and the headed pin are slid toward a thickened end portion of the center link whereby said thickened portion holds the side bars spread apart sufflciently to maintain the transverse T-heads on each pin within the transverse recesses in the outer faces of the side bars, thus holding the side bars and center links pivotally secured together. Whenthe center links and side bars are assembled to form a length of chain, the side bars and center links are arranged in alternate relationship along said chain, each center link having connected toeach end thereof a pair of spaced side bars and each such pair of side bars being connected at each end to an adjacent center link and so that pivotal movement is permitted between the adjacent center links and side bars about the center of said headed pins as an axis.

In addition to the great strength of this chain 7 Claims. (Cl. 74254) 2. its principal features are its adaptability as a sprocket chain, the absence of rivets, and the ease in which individual links may be removed from or added to the chain. While attempts have been made to devise other types of chain having the same rivetless feature, only the Weston type has taken hold in the trade and,

' except for the improvements recently shown by Herman 2,264,529 and Webb 2,298,604, the form of the chain has remained without significant change from, that originally shown by Weston in 1907. This invention is directed to improving the Weston chain, as modified by Webb and Herman, by improvements in the side bar used in such a chain, but of course the improvements can be applied in greater or less degree to other rivetless chains.

The Weston chain, due to its peculiar form and due, perhaps also, to the fact that it often drags along on floors or in troughs, etc., occasionally picks up bolts, screws, and small stray pieces of metal which become caught in the linkage. This frequently results in damage to the driving mechanism or the chain itself and interruption of plant operations. In fact, there have been instances in which plant operations have been sabotaged by the insertion of foreign objects, such as screw drivers or wrenches, in the linkage of such a chain. One object of this invention is the provision of a rivetless chain in which the accidental or intentional clogging of the chain by foreign objects is made less likely or more difficult.

These chains are generally forged of steel. The tolerances attainable in forging practice are sufficiently close to permit the pins and parts of the chain to be used as forged, however, certain locations which govern the pitch of the chain are customarily machined to closer limits. Burrs and rough orsharp edges often occur at the edge of the machined, locations. Another object of this invention is to provide a chain which will be so shaped that the machining which follows the forging operation will not create any such burrs or rough or sharp edges.

A further object of the invention is to follow the teaching of Webb 2,298,604 and use a high or thickened side bar so as to prevent misassembly and at the same time to locate the .thickest dimension at the outside of the side bar where the extra thickness will provide addiof this invention is to utilize a substantial portion of this otherwise wasted flash formed in the interior of the side bar of the chain for the purpose of preventing clogging, preventing misassembly, strengthening the link, of furnishing a panel-like area for a name-plate and by so curving the panel to insure proper engagement with the drive.

Occasionally, and due to inaccuracies in manufacture, improper wear occurs between the pin and the side bars of the chain, particularly when the chain is at a curve. An additional object of the invention is to so shape the side bar and the lock lugs thereon that wear of this. type will not occur.

These and other objects of the invention will become more apparent from the following description and the accompanying drawings in which Fig. 1 is a perspective view of the side bar of the chain.

Fig. 2 is a. plan. view of the. side bar.

Fig. 3 is a transverse sectional view taken alon the line 3-3 of Fig- 2.

Fig. 4 is a longitudinal. vertical sectional view taken along the line 44 of Fig. 2.

Fig. 5. is a. View, in smaller scale, showing the entire chain, as assembled.

Fig. 6' is a fragmentary plan View of a modified form of the. invention which may be compared with Fig. 2.

Fig. '7' is an end viewof the form shown in Fi 6..

Fig.v 8. is a fragmentary view of a. chain link as, heretoiore used in, practice. This drawing from the old art is included herein for purpose of comparison with Fig. 2.

Fig. 9; is. a side elevation of' the locking pin employed in the assembled chain of Fig. 5.

The assembled chain. as shown in Fig. 5, consists of three separate and different parts, called center links f, locking pins [6 and side bars I1. One unit or pitch. of. the chain consists of a center link l5, two. side bars IT on either side of the center link and two locking pins f6, each of which extends from the top of. one side bar, through the center link and to the, bottom of the other side bar so as to join the center links and side bars in end-to-end, relationship. As shown in Fig. 5, successive units may be joined together to form a chain of any desired len th. As this invention deals particularly with the side bar used in the chain, reference is made to Weston 870,704 for an explanation of the manner in which the chain is assembled or disassembledor units are added to it: or removed;

Turning, now to; the side bar H, its general form and shape is shown in, perspective in Fig. 1. In its; essentials the side bar is; a long narrow loop provided with notches; Iv 8 at each end formed to receive the head of a locking pin I6. The dotted outline on the right-hand side of Fig. 2 showsthe exact position of such a locking pin l6.

These side bars, as well as the other parts of the chain,, are commonly forged from solid pieces of stock, the metal from the central portions of the stock beirng, through successive operations, forced out to the sides to form the desired shape. As in all forging operations; there is a flash, or thin web of metal; which surrounds the object and which stretches across the location of any apertures, in the finished piece. The last forging operation isto punch out the flash.

In orderto avoid distortion of the shape-of the link in operation and particularly at turns of a conveyor line, the old practice was to provide a narrow strut l9 in the center of the side bar, see Fig. 8 which is taken from the old art. However, instead of forming such a strut, this invention takes advantage of the flash formed in the forging and utilizes part of the flash as structural part of the side bar. As shown in Figs. 1, 2 and 4, the side bar II is not provided with the conventional center strut of the old artinstead there is a relatively thin Web or panel 2! which extends across the inner part of the side bar 11, leaving an aperture 22 at either end barely large enough to. allow the head of a locking pin It to be inserted in the end of the side bar. The web 2 l. is the residue of the original inside flash which was formed in the forging operation and which extended from side to side and from end to end of the side bar ll. Instead of punching out this entire flash only the end portions are punched out to form the holes 22 and the balance of the flash. forms the; web 2! shown in the finished product, Fig. 1. The web 2| is, of course, quite thin. Some slight thickening at its ends, as at 23, may be desired as a protection against iracture during heat treating or when in use.

It will be noted that the web or panel 21 is curved so that its ends 23 are near the top surface of the side bar I'T, whereas the center portion is flush with the bottom of the side bar II. Such a curvature, in itself, is desirable in order to givev a stronger construction, but the reason for placing the central part of the web 2| flush with the bottom of the side bar 2| is an operating one which calls for explanation. These chains are ordinarily driven by sprocket wheels, the teeth of which project between two opposed side links H and engage and drive the ends of the center bars 15... In certain unusual conditions it might be that the chain could become cooked or tilted with relation to the drive sprocket and a tooth oi the sprocket might, upon entering engagement, catch in an irregularity in the underside of the side bar H. The web 2|, being a smooth sur-- face which curves to a point flush with the bottom of the side bar M, will guide the chain and sprocket tooth into proper engagement should there be a slight angular misplacement.

The hole, 24, in the center of the web 21 is provided for drainage should any liquid drip on the chain as it travels through the plant.

It may be noted that the side bar embodies the principles shown in Webb 2,298,604that is to say, at no place throughout the length of theside bar I? can the locking pin 16: seat as low as it can in the recesses or notches l8. Therefore, the chain can be assembled only when thelocking pins are in their proper position. This beneficial result'is accomplished by havingthe sides of the side bar l-Tl intermediate the notches 1-8 uniformly higherthan the height of these notched area's. Insofar as assembly is concerned, it may seem a matter of indifference whether the highest part of the side of the side bar is along the inside edge, the middle (as in Webb 2,298,604), or the outside edge. In this invention the side of the side bar H is highest at the outside edge-seeFig. 3 where a transverse cross-sectionof the sidebar I"! may; after making due allowance for'rounding of edges, roughly be compared to 'two opposed triangles having their apexes' pointing inwardly; This brings more metal, and hence more Wearing andbearing surface to the outside edge of the sidebar.

With one exception, some slight variations inthe outside and inside dimensions of theside bar I? are tolerable. The exception is the inside distance between the ends-in other words, the distance between the cylindrical section 25 at each inside end of the side bar II. This distance is one of the distances which determines the pitch of the chain at is locates the locking pins l6 and hence fixes the distance between successive units.

In the manufacture of the chain, the practice in the past, as shown in Fig. 8, has been to forge the" slots 22 with parallel sides 22a and with an end" part 2511 in the shape of a half circle slightly smaller in diameter than the width of the slots 22 and then to machine the half circle sections 25a to the correct size and the correct distance from one another. This gave the side bar shaped as shown in Fig. 8 (old art). sition between the machined portion 25a and the forged sides of the slots 22 is not smoothon the contrary, a corner, as'at 26a of Fig. 8, and even a burr, oftentimes exists at the edge of the machined section. If there is any play in the locking pin, the burr or corner at this point is apt to cause unusual wear on the locking pins l6 and ultimately a change in the pitch.

The side bar of this invention has a diiferent shape than the side bar of the conventional chain. As shown in Fig. 2, the sides of the slot 22 are not parallel. Near the center of the side bar the slot is appreciably wider than the diameter of a locking pin l6, but it tapers down so that at the end, and at the point where the locking pin engages, the width of the slot 22 is just sufficient to accommodate the pin. The tapered portion is designated as 26 on Fig. 2

and it will be apparent that some tolerance-in the exact location of the cylindrical end section 25 is permissible without effecting a sharp or abrupt change anywhere in the contour of the slot 22. In other words, the tapering section 26 has avoided the cause of any sharp corner as at 26a in Fig. 8, and the possibility of wear on the, looking pin I6 is reduced.

In Figs. 6 and 7 is shown a modification of the side bar 57, intended further to reduce the possibility of wear and loss of exact pitch.

When the chain is assembled, the locking pins l6 are locked against rotation relative to the side bars I! by the engagement of the T-shaped heads 21 of the pins with the slots [8, as clearly shown in Fig. 5. As the chain is in tension, the locking pins are normally urged endwise and toward the farther face or end shoulder 28 of the slots 18. By correctly locating this end shoulder 28 with relation to the surface 25, any possibility of play between the pins Ni and the side bar I! can usually be avoided. If, however, the T-shaped head 2! of the locking pins i6 is not accurately formed, it may bear against the middle of the shoulder 28 rather than against the ends and thus permit rocking of the locking pin l6 and rotation and wear. In the embodiment shown in Figs. 6 and 7, such a possibility is avoided by removing the middle portion of the end shoulder 28. As shown therein, the end shoulder 28 is formed by two bosses 29 on either side of the end of side bar I! leaving a space 30 between the bosses. The bearing on the head 21 is necessarily at the ends thereof and, hence, variations in the middle portion of the head 21 will have no effect on the assembly and cannot become the cause of rocking of the locking pin l6.

From the foregoing those familiar with the art will readily appreciate the advantages of the chain in actual practice.

However, the tran-- In the first place, there is the provision of the web .or panel 2 l, formed from the original flash. A comparison between Figs. 2 and 8 shows that the aperture 22 is much smaller than the old aperture 22a, especially after the locking pin [6 is in place. Thus there is much less chance that a stray bolt or a screw driver or any other foreign object may accidentally or intentionally become enmeshed in the aperture and cause breakage of the chain. Also the extra length of the web 2| compared with the narrow strut I9 is a further protection against distortion of the side bar [1. Again, the extra length of the web 2| takes advantage of theteachings of Herman 2,264,529 and would prevent the misassembly of the chain even though the portions of the side bar I I centrally of the recessed areas 18 were thinned down as in the old art. Lastly, the Web 2! furnishes an excellent location for a name or trade-mark.

Second: by making the web or panel 2! curved, the strength of this thin section is improved and misengagement with the driving mechanism is prevented.

Third: the high edge on the side bar prevents misassembly.

Fourth: the non-rectangular section in the side of the side bar, by which more surface is brought to the outside edge of the side bar, offers more wearing area.

Fifth: there is the taper '26 in the slots 22. By this taper customary methods of manufacture can be used without resulting in corners or burrs which cause Wear and loss of pitch.

Sixth: and in the alternative form shown in Figs. 6 and 7, there is the relief 36 which divides the end shoulder 28 and eliminates the possibility that a slightly misformed locking pin H5 may rock when the chain is going around a curve.

Those skilled in the art will readily conceive of various modifications and changes in the particular form of the invention shown herein and in the adaptation of the form shown herein to other types of rivetless chain-all without departing from the full scope of the invention as defined by the appended claims.

I claim:

1. A side bar for a conveyor chain of the type wherein the chain is composed of a series of slotted links each of which is connected to its adjacent link by a pair of side bars and by headed locking pins which pivotally and detachably connect the ends of said links to the adjacent ends of a pair of side bars, characterized by said side bar having at each extreme end an end shoulder for engagement with the ends of the head of one of said locking pins and the middle part of said end shoulder being relieved as to avoid contact with said head.

2. A side bar for a conveyor chain of the type wherein the chain is composed of a series of slotted links each of which is connected to its adjacent link by a pair of side bars and by headed locking pins which pivotally and detachably connect the ends of said links to the adjacent ends of a pair of side bars, characterized by said side bar being constructed with the interior filled by a web, the thickness of such web being substantially equal to the thickness of the flash which would remain in the center portion of a side bar constructed as a forging from a solid piece of material, except at either end of said side bar where apertures are provided suflicient to permit the insertion of said headed locking pins, said side bar having at each extreme end an end shoulder for engagement with the ends of the head of one ansmoo (if said locking pins, and the middle part of each of. said. end shoulders being relieved as to avoid contact with said head.

3. A side bar for a conveyor chain of the type wherein the chain is composed of a series of slotted links each of which is connected to its adjacent link by a pair of side bars and by headed locking. pins which pivotally and detachably connectv the ends of said links to the adjacent ends of a. pair of side bars, characterized by said side bar having. its side portions non-rectangular in section, the largest face of said section facing outwardly so as to present an increased wearing surface.

4:. A side bar fora conveyor chain of the type. wherein the chain is composed of a series of slotted links each of which is connected to its adjacent link by a pair of side bars and by headed locking pins which pivotally and detachably connect the ends of said links to the adjacent ends of a pair of side bars, characterized by said side bar having a longitudinally curved central panel of thin section extending between the sides of said side bar.

5. A side bar for a conveyor chain of the type wherein the chain is composed of a series of slotted links each of which is connected to its adjacerrt link by a pair of side bars and by headed locking pins which pivotally and detachably connect the ends of said links to the adjacent ends of a pair of side bars, characterized by said side bar having a longitudinally curved central panel of thin section extending between the sides of said sidebar, the middle of said panel being flush with the inside surface of said side bar, and the ends of said panel terminating intransversely extending thickened ribs to form with said panel reinforcing means for resisting distortion of said side bar.

wherein the chain is composed of a series of slotted links each of which is connected to itsadjacent link by a pair of side bars and-by headed nect the: ends: of. said links to= the adjacent ends of a pair of. side bars; characterized by" said side her being constructed. with an aperture at either end for receiving one of: said locking pins and; with a central strengthening weh having a curved longitudinal crosssectionextending between said apertures.

7 A side bar for a conveyor chain of the type wherein the chain. is composed of" a series of slotted links each c1. whichv is connected to itsadjacent link by'a pair'of. side bars andby rec tangularly headed locking pins which pivotally and detachably connect the ends of. said links to the adjacent ends: apair of side bars; characterized. by said side bar being constructed with an aperture at end for receiving one of said locking pins and with a central strengthening webhaving a curved longitudinal cross section extending between said. apertures, theouter end of each such aperture being; formed in the arc of a circle. and the sides of each such aperture flaring gradually and smoothly from said arc, said sidebar" having at each extreme: end an.- end shoulder for engagement with the endsof the. head of alocking pin, and. the middle part of each of said end shoulder beingv relieved. as to= avoid contact with the head oi said. locking pint.

J ERVIS B. WEBB.

REFERENCES.- CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 850,704 Weston. n Nov. 12, 1907 13082332 Howe etaali Dec. 23-, I913 1,122,831 Wilmot et a1 Dec. 29, 1914 1,453,083 Bachman et'al. Apr. 24, 1923 1,979*,592 Weiss Nov. 6, 1934 2,229,106 Iuomaindo Jan. 21., I941

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