USRE22488E

USRE22488E - Chain

Info

Publication number: USRE22488E
Authority: US
Publication date: 1944-05-30

Description

5 0,1944. A. E. FOCKE Re. 22,488

CHAIN Original Filed May 25, 1939 INVENTOR ATTORNEYS.

Reissued May 30, 1944 CHAIN Arthur E. Focke, Indianapolis, Ind., assignor to Diamond Chain and Manufacturing Company, Indianapolis, Ind., a corporation of Indiana Original N 0. 2,293,029, dated August 18, 1942, Se-

rial No. 275,715, May 25, 1939.

Application for reissue August 4, 1943, Serial No. 497,317

16 Claims.

My invention relates to chains, especially power-transmission chains, and has for its object the improvement of the wearing qualities and/ or the strength of such chains.

The design of a chain of the type with which my invention is concerned is usually a compromise between wear-resistance and strength. Certain parts of the chain are subject to both wear and stress; and, in the steels of which chain elements are commonly formed, strength and wear-resistance are, to an extent, incompatible properties. That is, a chain element of a steel selected or treated to obtain maximum strength will be relatively susceptible to wear; and, conversely, a, chain element of a steel selected or treated to obtain maximum wear-resistance will be relatively weak. I use the term strength herein to denote not only resistance to steady loads but also resistance to fatigue and shock. Through the practice of my invention, I am enabled to make chain elements possessing the usually incompatible properties of relatively great strength and relatively high wear-resistance, and thus I can produce chain which, for any given strength, will possess greater wear-resistance or, for any given wear-resistance, greater strength than prior chains of which I am aware.

In the conventional roller-type chain, which for purposes of illustration may be taken as an example of common forms of chains to which my invention is applicable, bushing-links alternate with pin-links, the latter having pins which extend through the bushings of the former. As the result of flexing of the chain over its associated sprockets, wear tends to occur at the interengaging faces of the bushings and pins, such wear being localized over about one-half the circumference of those interengaging surfaces. At the same time, the pins are also subjected to bending stresses and to shear. In embodying m invention in such a chain I subject the pins, and possibly also the bushings, to a differential treatment which will increase wear-resistance at those surface portions most subject to wear while still leaving the remaining surface portions possessed of their normal, or even an enhanced, strength.

The accompanying drawing illustrates my invention: Fig. 1 is a plan of a portion of a rollertype power-transmission chain with portions thereof broken away; Fig. 2 is a side elevation of the chain with parts thereof broken away on the section line 2-2 of Fig. 1; Fig. 3 is a plan, in partial section, or a bushing-type chain; and

Fig. 4 is a fragmental isometric view of a blocktype chain.

The chain shown'in Figs. 1 and 2 is made up of alternating pin-links and bushing-links. Each of the latter comprises a pair of spaced side plates Ill having near their end holes for the reception of bushings l I, while each of the pin-links comprises a pair of side plates l2 having at their ends holes for the reception of pins 13. The pins [3 of the pin-links pass through the bushings I l of the bushing-links and so serve to make a continuous chain. Rollers l4 mounted on the bushings II engage the teeth of the driving and driven sprockets (not shown).

In a chain such as that illustrated and described, the tension in the chain is transmitted between each pin l3 and its associated bushing II at that side of the pin indicated at i6 in the drawing, i. e., that side of the pin which lies nearest the center of the associated pin-link. As the chain passes over the sprockets, the bushings II rotate on their respectively associated pins l3; and, as a result of the load transmitted between each pin and bushing at the point indicated by the reference numeral l5 and for a distance in opposite directions from that point, a marked tendency to wear occurs.

To resist this wearing tendency it has been proposed to harden the steel'pins and bushings, or at least the surface portion thereof. However, the hardening process or heat treatment best calculated to increase Wear-resistance is not the heat treatment which will result in maximum strength, and vice versa. In fact, with some steels, hardening to produce maximum wear resistance may make the steel weaker than it was before treatment. As a result, a chain which has such elements as pins and bushings hardened, either throughout or uniformly over their surface portions, to produce maximum wear-resistance will be weaker than it might otherwise be. Conversely, a chain which has its elements treated to produce maximum strength will be less wear-resistant than it might otherwise be.

To make a chain which will possess both satisfactory wear resistance and satisfactory strength I subject chain elements which must resist both wear and stress to a differential heattreatment designed to produce or retain satisfactory wear resistance over surface portions sub,- ject to wear and to produce or retain satisfactory strength throughout other portions. De-

pending upon several factors including the size of the chain elements and the use to which the chain is to be put, the treatment of the chain elements may have for its primary purpose either the increasing of strength or the increasing of wear-resistance. If the primary purpose is toincrease strength, the differential heat-treatment results in a retention, or even in an enhancement, of the effective wear-resistance} while if; the primary purposeis to increase wear-'resistance, the difierential heat treatment results in a retention, or even in an enhancement, Of'..i'

strength.

. In the case of roller chain, it will usually be necessary to subject only the-pins to th dii Ter--., ential heat-treatment, although the bushings, may be similarly treated if desired. There are:

several different ways in which thepins (or bushings) may be treated to produce the desiredfdif} ferential characteristics. For eiiample, if'the pins or bushings are made of mild steel, as they usualtrated in Fig. 3 a bushing-type chain in which the bushings themselves directly engage the sprockets without any interposed roller. In such a chain the bushings 30, instead of being of uniform diameter throughout their length a in the chains of Figs: 1 and 2,- have a body diameter which enablesfi tliemz-to' co-Qperate 'With the associated sprockets and end portions of reduced diameter which are received in the side plates In of the bushing links. occur most rapidly on that side of the pin indi- In such a chain, Wear tends to cated by. the reference numeral 16, and each pin maybe treated, as previously described, so that it .will be relatively. wear-resistant at that point and relatively strong elsewhere.

'Ihe chain shown in Fig. 4 is of the block type, in'wh'ich'the'pin-links |2I3 are interconnected by blocks 25 having at their ends holes 26 through ly are, I may increase the wear-resistance of those portions subject to wear by case-hardening such portions, confining the case-hardening to the desired portions b treating the remaining portions, as by copper-plating, to prevent the penetration thereof by carbon from the carburiz} ing material employed in the case 'hardening process. By this treatment, the p ns or bushings are rendered relatively hard and wear-resistant over those surface portions where wear is most likely to occur,.while the remainder of the thereof as by case-hardening, and then subject i the pin or bushing to a: differential tempering process, tempering those portions subject to wear to a point which will produce optimum wear re,- sistance and those portions not subject to wear to a point where optimum strength andtoug'hness will result for example, I may subject the. wearing portions to tempering temperatures; in the neighborhood of 200, while theremaining portions are subjected to a temperature in the neigh borhood of 500. Such differential heating of the chain elements to obtain differential tempering may be readily accomplished by knownfmethods of heating, such as through the use of high-frequency induction, and may be'employe'd not only to increase wear-resistance over portions subject to wear but also (and concomitantly) to increase the strength of other portions. I I 1 In assembling the chain, it is essential that the wear-resistant portion of each pin or bushing be disposed in proper relation to the associated side plates. To aid in securing this disposition of the pins or bushings, they may be provided exteriorly with indicia indicatingfwhich side thereof is the harder side. In the drawing, I have shown each bushing II as provided in one end with a shallow radial groove 20011 that side thereof opposite the harder portion, and each pin I3 as provided with an eccentricrecess 2| near the harder portion thereof. By assembling the links of the chain with the indicia on the pins and the bushings near the center of the respectively associated links, the harder portions of the pins and bushings will be disposed in proper relationship. That is, the harder portion of each pin will be the portion thereof nearest the center particular roller-type of power-transmission chain illustrated in Figs. 1 and 2. 'Thus, I have illuswhich the pins l3 pass. Here again each pin tends to wear most rapidly on that side thereof nearest the center of the associated pin link, and that side-portion of the pin maybe treated as above described'to obtain desired wear-resistance and strength. If'desir'ed, the blocks may also bedifferen'tially treated.

hatever the type of chain, the treatment of the pins to produce differential surface char acteristics results in a more satisfactory chain; for the p'ins 'are str'onger'and tougher than if their entire surface portions were treated topromote wear resistanceand will wear better than if they were treated throughout to increase their strength andtoughness. The bushings, whether of. the roller-type chain "of Figs. .1 and 2 or of the bushing-type chain of Fig. 3, may also bedifferentially treated; but, as pointed out above, the Wear resistanceof a bushing: 15 a more important consideration than is its strength. z

Other factors: than wear-resistance and strength may-influence the arrangement of the relatively. hard and relatively strong, portions of the chain elements. Thus the rigidity of, an individual chain link depends largely upon the fit of. the pins (or bushings.) in the associated side bars It is customary for the pins to have a press fit in the sidebars; and in some instances, especially Where the pins possess approximately the same hardness as theside bars intowhich they ,are pressed, galling occurs as the pins'are pressed into the side bars and thefit consequently becomes less firm than it otherwise might be. The possibility of, galling may be reduced if the pin-ends which enter the side bars, or at least the cylindrical surface portions of such pin' ends, are made harderthan the sidebars. "By any of the methods above described the cyIi'ndricaLI'surface of the pin maybe made, relatively'fhard throughout its circumference. at the ends of'the pin and. over a .portion of itscircumference betweensuchen'dathe remaining. portions of the pin being relatively stronger and softer.

Iclaim as. my inv'ention;

1.,A powertran smission chain, comprising a1- ternating pin links and. bushing-links, each of said bushing-links. comprising two. spaced bush ingsandieach of said pin-links comprising two spaced pins passing respectively through bushingsof adjacent bushing-links, that surface portion of each pin nearest the center of the, pinlink being'f harder than'the remainder of thepin andthe adjacent surface portion of the associated bushing 'bi'n'g'harderthan the remainder of such 2;jdpower tr'ansmission chain, comprising-a1? te'rnatin'g' pin-links and bushing-links, each or said bushing-links comprising two spaced bushings and each of said pin-links comprising two spaced pins passing respectively through bushings of adjacent bushing-links, that inner surface portion of each bushing nearest the adjacent end of the bushing-link being harder than the remainder of the bushing.

3. The invention set forth in claim 2 with the addition that each bushing is provided exteriorly with indicia indicating which surface portion thereof is the harder.

4. The invention set forth in claim 2 with the addition that each bushing is provided on at least one end surface with indicia indicating which surface portion thereof is the harder.

5. A power-transmission chain, comprising a series of interconnected links, alternate ones of said links being pin-links comprising spaced side plates and unitary pins which pass through said side plates and also through end portions of the other links, that surface portion of each pin nearest the center of the pin link being harder than the remainder of the pin.

6. A power-transmission chain, comprising a series of interconnected links, alternate ones of said links being pin-links comprising spaced side plates and unitary pins which pass through said side plates and also through end portions of the other links, that surface portion of each pin nearest the center of the pin link being more wearresistant and less strong than the remainder of the pin.

'7. The invention set forth in claim 6 with the addition that each pin is provided exteriorly with indicia indicating which surface portion thereof is the harder.

8. The invention set forth in claim 6 with the addition that each pin is provided on at least one end surface with indicia indicating which surface portion thereof is the harder.

9. A power-transmission chain, comprising a series of interconnected links, alternate ones of said links being pin-links comprising side bars and spaced pins whose end portions pass through the side bars and whose intermediate portions are received in end portions of the other links, the surface portions of the pins at the ends thereof and the surface portion of the pin between the side bars and nearest the center of the pin link being harder than the remaining portions of the pin.

10. A chain, comprising a longitudinal series of chain elements and means associated with adjacent elements for pivotally interconnecting them, said means including a transverse pivot pin non-rotatably associated with one of each pair of adjacent elements and a bushing which rotatably receives said pin and which is nonrotatably associated with the other element of such pair, that surface portion of said pin nearest the longitudinal center of its associated element being harder than the remainder of the pin and the adjacent surface of said bushing being harder than the remainder of such bushing.

11. A chain, comprising a longitudinal series of chain elements and means associated with adjacent elements for pivotally interconnecting them, said means including a transverse pivot pin non-rotatably associated with one of each pair of adjacent elements and a bushing which rotatably receives said pin and which is non-rotatably associated with the other element of such pair, that inner surface portion of said bushing nearest the end of its associated element being harder than the remainder of the bushing.

12. A chain, comprising a longitudinal series of chain elements and means associated with adjacent elements for pivotally interconnecting them, said means including a unitary transverse pivot pin non-rotatably associated with one of each pair of adjacent elements and rotatably received in a transverse opening in the other element of such pair, that surface portion of said pin nearest the longitudinal center of its associated element being harder than the remainder of the pin.

13. In a chain having a series of links each comprising a pair of transversely spaced side bars, means for pivotally interconnecting adjacent ones of said links, each of said means comprising a pivot pin whose end portions pass through and are rigid with the side bars of its associated link and a bushing rotatably mounted on the intermediate portion of said pin and having its end portions rigidly received in the side bars of its associated link, the surface portions of said pin at the ends thereof and the surface portion of the pin within the bushing and nearest the center of the associated link being harder than the remaining portions of the pin.

14. In a chain-link, a pair of longitudinally extending, laterally spaced link-plates provided at corresponding ends with aligned openings, and a unitary pivot pin non-rotatably received in and extending through said openings and adapted between said plates to be rotatably received in a transverse opening of another chain-link, that surface portion of said pin between said plates and nearest the longitudinal center of said plates being harder than the remainder of the pin.

15. In a chain-link, a longitudinally extending link-plate provided near one end with a transverse opening and a bushing non-rotatably mounted in said opening and adapted to rotatably receive a transverse pivot-pin of another chain-link, that inner surface of said bushing lying nearest the end of said link-plate being harder than the remainder of the bushing.

16. A chain, comprising a longitudinal series of chain elements and means associated with adjacent elements for pivotally interconnecting them, said means including a transverse pivot pin non-rotatably associated with one of each pair of adjacent elements and rotatably received in a transverse opening in the other element of such pair, that surface portion of said transverse opening nearest the end of its associated element being harder than the remainder of the element in which it is located.

ARTHUR E. FOCKE.