US2507025A - Center link for rivetless chains - Google Patents

Description

y 1950 A. w. LEMMON 2,507,025

CENTER LINK FOR RIVETLESS CHAINS Filed Jan. 19. 1945 EN TOR.

' Aux/5% 15mm I Patented May 9, 1950 UNITED STATES PATENT OFFICE Alexis W. Lemmon, Columbus, Ohio, assignor to Jervis B. Webb Company, Detroit, Mich., a corporation of Michigan Application January 19, 1945, SerialNo. 573,517

4 Claims.

This invention relates to 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 was the subject matter of Weston Patent No. 870,704, issued November 12, 1907. In addition to its great strength, its principal features are its adaptability as a sprocket chain, the absence of rivets, and the ease with 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 but the form of the chain has remained without significant change from that originally shown by Weston in 1907. This invention is directed to certain improvements in the Weston chain having for their object the strengthening of the chain to improve the functioning thereof in operation and to effect certain economies in the cost of fabricating the same.

The original rivetless chain to which the present invention is directed and which formed the subject matter of the Weston Patent No. 870,704 consists of a plurality of alternately arranged 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 b 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 narrow 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 the three slots, next turning the side bars at a right angle to the center link and seating the heads of the pins in the transverse recesses formed in the ends of the side bars, after which the pair of side bars and the headed pin are slid toward the thickened end portion of the center link whereby said thickened portion holds the side bars spread apart I sufilciently 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. When the center links and side bars are so 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 to each end thereof a pair of spaced I 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 the original Weston chain the center links thereof, although made as forgings, have the general form that would result if a flat piece of steel approximately 1% of an inch in thickness were bent to form an elongated link having the ends thereof curved and so that the inner face of the bar at each end of the link forms a substantially semi-cylindrical bearing surface for the body portion of the connecting headed pin.

In the original Weston chain the end portions of the center links, as shown in the Weston Patent No. 870,704 are approximately twice as wide as the central portion of the link and the bar-like piece of metal which forms the link is provided with a comparatively sharply inclined section or taper where the wider end portions connect with the thinner central portion thereof; the top and bottom surfaces of the wider end portions of the links being formed as flat or plane surfaces for engagement by the inner faces of the side bars. Except for a slight tapering of the side walls of the bar of material from the longitudinal center thereof to the top and bottom faces for providing the necessary draft for the forging dies, the bar of material which formed the link was of substantially uniform cross-sectional thickness as distinguished from a uniform width of the bar as just described to provide the wider end portions thereof.

It has been found in practice that the weakest point of the keystone chain and the point at which most failures have occurred is at the comparatively sharp line that marks the demarcation between the thinner central section of the link and the tapered section thereof which connects the wider end portion of the link with the said central thinner section. a

One of the principal objects of the present invention therefore is to provide a new and improved construction whereby there will be no sharp line of demarcation to form a cleavage line as with the Weston chain as heretofore universally constructed.

Large quantities of the Weston or keystone chain have been used for many years in overhead trolley installations in which the chain is supported for movement along a supporting loadcarrying I-beam track by means of trolley brackets such as disclosed in the patent to Jervis B. Webb et al. No. 2,398,062. issued April 9, 1946. As shown in the said Webb patent, a pair of similar bracket members are provided each having an outwardly flaring upper portion having a trolley wheel rotatably mounted thereon for engaging the lower flange of the I-beam and a lower central portion through which and the flat web of a load-supporting clevis or hook member, bolts are passed to secure the two bracket members and the load-supporting member in assembled condition, the flat web of the clevis or load -supporting member passing through the elongated slot of the center link so that when the two bracket members and loadsupporting member are secured together, the brackets are held in assembled relation to the I-beam supporting track and to the chain; the bracket thus serving to hold the chain suspended from the supporting track and so that the weight of the loads which are being supported is carried entirely by the bracket members and track without any of the load being transmitted to the chain which serves entirely as a traction device to propel the trolley brackets and loads along the track.

A further object of the present invention is to so construct the center link of a keystone chain as to provide locating surfaces thereon which will cooperate with similarly formed surfaces on a bracket of the type shown in the said Webb patent in such a manner that the bracket members and center link of the chain will be rendered automatically self-centering when the parts are assembled.

The above and other objects of the invention will appear more fully from the following more detailed description and by reference to the accompanying drawings forming a part hereof and wherein:

Fig. 1 is a side elevation of a center link for a Weston or keystone chain and constructed in accordance with the principles of the present invention;

Fig. 2 is a plan view of the structure shown in Fig. 1;

Fig. 3 is an enlarged sectional detail taken on the line 3-3 of Fig. 2;

Fig. 4 is a similar enlarged cross-sectional detail taken on the line 4-4 of Fig. 1;

Fig. 5 is a side elevation of a center link and trolley bracket in assembled condition, and

Fig. 6 is a side elevation showing the manner in which a center link and pair of side bars are connected by a headed pin.

As shown in the drawings, the link It, as heretofore explained, is constructed as a forging and is of the general form of a flat bar-like structure in the form of an elongated link having side walls H and curved end sections I2 which enclose an open elongated slot [3.

The link I0 is of symmetrical construction in that both halves of the link considered either from the transverse central plane or the longitudinal central plane are identical in configuration.

As shown most clearly in Fig. 1 of the drawings, the top and bottom faces of the link adjacent to the curved end section ii are provided with a convex curvature as indicated by the reference character [4. The purpose of this curvature is to provide a rounded surface upon which the inner faces of the adjacent side links of the chain bear so that when the chain is passing around a vertical curve or bend in the conveyor's line of travel, relative movement between the side bars and ends of the center links may occur without undue binding or cramping such as would occur if the top and bottom faces of the thickened end portions of the center link were flat and in relatively close contacting engagement with the flat inner faces of the side bars as shown in the said Weston patent.

It will also be noted by referring to Fig. l of the drawings that the top and bottom faces of the center link are also curved or bellied outwardly at the center thereof, as indicated by the reference character l5, and that this outwardly convex portion is connected to the convexly curved portion i 4 by curved portion is of fairly large radius and so that the adjacent outwardly curved sections it and I5 are merged with the curved sections IS in such a way that no sharp dividing line or line of demarcation is formed such as would provide a line of cleavage.

As the center links of the chain are used in connection with a headed pin H, the central body portion I 8 of which bears against the inner face IQ of the curved end section l2 of the center link, the said surface I9 is machined to provide a substantially smooth surface against which the pin bears. In the machining of the surfaces It! as the keystone chains were heretofore constructed, either an objectionable sharp projecting shoulder or a sharp recess was usually formed approximately at the point indicated by the reference character 20 which tended to cause undue wear upon the body of the headed connecting pin. The formation of such a shoulder is obviated in the present invention by providing the inner face of the side walls Ii of the link with the inwardly curved or tapered portions indicated by the reference character 2| in Figs. 2, 3 and 4 of the drawings, these inwardly tapered or recessed portions as clearly indicated in Fig. 2 being of substantially greater diameter than the diameter of the body of the connecting pin and terminating substantially midway between the top and bottom faces of the link in a slightly flattened surface 22 that merges with the flash portion 23 of the link As the link is made as a forging in a forging press by the use of a split die consisting of complementary similar upper and lower die sections. both the inner and outer faces of the side and curved end walls of the link taper outwardly from the top and bottom faces thereof towards the center of the link to the point where the flash 23 is located, such taper being indicated in Fig. 2 of the drawings by the reference character 25, this tapering of the inner wall merging gradually into, or with, the inwardly tapered recess 2| hereinbefore described.

As will be understood from the foregoing, after the rough forging of the link has been completed, the inner faces of the end walls l2 thereof are machined to form the finished bearing surfaces IQ for the cylindrical body portion it of the headed connecting pin II. The center links ID are secured to the side bars 26 in the manner shown in Weston patent and as hereinbefore described by inserting a connecting pin I! with the elongated head thereof in parallel alignment to and through the elongated slots in the end portions of the side bars and the elongated slot l3 of the center link, while the side bars 26 and connecting pin H are held at the central portion of the center link which is of reduced thickness. When the headed pins have been seated within the recesses 21 provided in the ends of the side bars, the side bars with the headed ends of the pin seated within said recesses are then moved to the thickened end portions of the center link, the greater width of the link at the end portions thus holding the side bars spread sufliciently apart so that accidental displacement of the heads of the pins from the recesses 21 cannot occur.

If the chain is to be used as a part of an overhead trolley installation, the load carrying member 28 is inserted through the elongated slot l3 of a center link Ill and a pair of bracket members 29 are bolted together and to the member 29 by means of a bolt 30 which serves to hold the pair of bracket members 29 and the member 28 in assembled condition, the bolt 30 not only serving to hold the trolley wheels 3| of the bracket in engagement with the supporting I-beam track member 32, but also to hold the brackets 29 and member 28 securely united with the center link IU of the chain. The lower faces of the trolley bracket members 29 form shoulders which abut against the top faces of the side walls ll of the center link I while the lower faces of the said side walls abut with a shoulder 33 formed on each side of the load-supporting member 28; the engagement of the shoulders on the brackets and member 28 serving to secure the chain to the brackets and maintain said chain in properly spaced relationship to the supporting track 32. As will be noted from an inspection of Fig. 5, the lower faces or shoulders of the trolley brackets 29 and the upper faces of the shoulders 33 hold the chain properly spaced below the track 32 with the chain link II in proper driving relationship with the brackets 29. It will be seen from Fig. that the lower faces of the trolley bracket 29 and the upper face of the shoulder 33 formed on the member 28 are curved to cooperate with the outwardly bellied central portion ii of the link; the similarly curved portions of the trolley bracket members and of the central portion of the link serving to automatically locate the bracket properly centrally of the link and to restrict relative longitudinal movement of the parts after the brackets and link members have been secured together in assembled condition.

While I have shown a satisfactory constructional example of the present invention, it will be understood that many changes, variations and modifications of the specific constructional details may be resorted to without departing from 6 without the formation of any sharp lines of demarcation or cleavage.

I 2. A center link for a rivetless chain, said chain consisting of a plurality of alternately arranged center links and pairs of side bars connected together at their adjacent ends by readily detachable headed connecting pins and wherein said center links are in the form of an elongated link having substantially straight side walls and curved end walls which enclose an elongated slot through which the body portion of said connecting pin passes, characterized by said side walls along the major central portion thereof being provided with a thickened central portion.

3. A center link for a rivetless chain, said chain consisting of a, plurality of alternately arranged center links and pairs of side bars connected together at their adjacent ends by readily detachable headed connecting pins and wherein said center links are in the form of an elongated link having substantially straight side walls and curved end walls which enclose an elongated slot through which the body portion of said connecting pin passes, characterized by the top and bottom of said side walls along the major central portion thereof being curved outwardly and symmetrically with a uniform curvature to providesaid link with a thickened central portion, and the inner and outer surfaces of the side walls of said link tapering inwardly and gradually from a plane extending transversely through substantially the longitudinal center of said link to the top and bottom faces thereof.

4. A center link for a rivetless chain, said chain consisting of a plurality of alternately arranged center links and pairs of side bars connected together at their adjacent ends by readily detachable headed connectin pins and wherein said center links are in the form of an elongated link having substantially straight side walls and curved end walls which enclose an elongated slot through which the body portion of said connecting pin passes, characterized by the top and bottom of said side walls along the major central portion thereof being curved outwardly and symmetrically with a uniform curvature to provide said link with a thickened central portion, and the top and bottom surfaces of said link adjacent the ends thereof also being curved outward symmetrically with a uniform curvature to form the ends of said link also as thickened portions, and the thickened end and central portions of said link being connected along the top and bottom faces of said side walls with symmetrically inwardly curved re-entrant portions which merge gradually with the outwardly curved central and end portions thereof.

W. LEMMON.

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

UNITED STATES PATENTS 5 Number Name Date 870,704 Weston Nov. 12, 1907 1,464,267 Harrison Aug. 7, 1923 1,595,580 Btohl Aug. 10, 1926 1,687,005 Brock Oct. 9, 1928 1,748,334 Evans Feb. 25, 1930 1,906,097 Prlbil Apr. 25, 1933 1,962,531 Shafer June 12, 193".- 2,095,022 Bishop Oct. 5, 1937 2,242,065 Gaboury May 13, 1911

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