US2615735A - Spring retaining ring for machine parts - Google Patents

Description

Oct. 28, 1952 HEIMANN ETAL 2,615,735

SPRING RETAINING RINGYFOR MACHINE PARTS Filed Dec. 27, 1949 m4 32 :lf se IO 32 XJX F|G. l I 34 Mb as v F t I FIG 2 Q l l I 2 I x l l 1 I 44 43 I lnveniors HEINRICH HEIMANN a LAWRENCE BROZEK,

By W 4 a Attorney Patented Oct. 28, 1952 SPRING" RETAINING RING-FOR MACHINE.

PARTS Heinrich: Heimanm, New York; and Lawrence Brozekg; J ackson: Heights, N. Y.", assignors/ t0:',. Waldes KohinoorhInc Long Island City, N. Y., a corporation. of NewrYork ApplicatibnDecember 27, 1949', .S riaPNb} 135, 23 6' l" This invention relates toLimprovementsdn re-- ta-ining ring; assemblies". of thertype ingwhich a machine ipartmountedt' on orzin :a-lcarriersuch as; at shaft. or=housingi is. located. andasecured in fixed. position and: against. axial displacement.- by; aspring, retainingring of: split or open-endedannular form capable; when springeseated in. a groove: provided: in said carrier, of providing an: artificial shoulder-for. said machine." part.

Conventional retaining-assemblies asaforesaid heretofore employed retaining rings-.- character--- ized by solid section throughout their circumfer-- ence; being either' fashioned from stripsor. wire ofiuniform. (round; square. or rectangular). sec-'- tionwhich are .bent to ring formation, or blank-ed fromstrips orsheetsto open-endedannula-r form, with. section heights decreasing from the middle. portion of thering totheiree enda-w-hich-define the. ring gap, .so that .the ring; deformscircularly,

Bothof theaforesaid ring typesihave a definite limitation i'nthe degree which they can be spread:- or. contracted.v in assembly without taking. on. a.- permanentlset, which depends on the. maximum" section. width of said rings. It is. obviousialso... that for secure seating. and. ability to. provide. an effectiveslioulder theiring secummu thave substantial height. As aconsequence theca pacity, of. the: ring tospread or contract-is .rela tively smalL. because: the workingsstresses must not exceed, the yield strength of; the :ring mate-- rial toavoida permanent. set-.. v Thus; for; rings: of. uniform section heighirthe. degree of spreading or contracting is limited to 57% of ring diameter, while taperederingsflhave only a slightly greater spreading or contracting capacity of from 10-14%; I

Another disadvantage in the use of conventlona'l retaining rings in such" assemblies isithat; since the variations-in diameterwhich split" or' open rings of solid section allow for a given ring dimension are very small, the prior-retaining ring was individually dimensioned to aparticularhsize shaft or housing bore and could not be effectively used with shafts or housings having even a slightly different size than that for which the ring was designed. Furthermore, itis-the very nature of conventional retaininggringsth'at. they require special tools for assembly andrdisassembly; and theyrcannot be easily adjusted. t0.-S01V8- t1lQ"pIfOb 2--Claims.. (01. 2874s) lem of taking up any considerable end pl'ay" of the machine.partzintended to be located thereby.

A principal object; of; the present: invention is the "provision :off a retaining :ring assemblyof the above? referredifto class employing a retaining;

ring which istfreezofz-the aforementioned limit'a tions" and disadvantages: of conventional retain-" 'g; rings of solid section, which: uses; instead-, a: retaining: ring, which may: havetra: spreading or contracting: capacity up to 100%: of. ringadiamt-t eterinstead of froma101-l4.% asi-with thei'prior tapered retainingiring; without thei'dang'er. oi the ring taking on a permanent set.,: i I

Another? object; of. the --invention: is: the: pro? vision of a novel retaining ring assembly employing' at coiled-wire'retaining ring: as hereinrde scribed,, which: is. constructed. and: arranged to. take-up end play, ofv the machine part;to. be lo' cated, up tothe sum total of the-tolerances: likely to be encountered or: required: in; such..a'ssem:+.-

blies 7 Yet another obj ectzofi'the' inventionzis'ith'ewpro vision ofa a. novel retaining" ring assemb1y made= possible by the. use: of: a. coi1ed'-wireretaining ring. and which hasthe capacity of takingupsen'd:v

play between. the machine. part .located by said: ring. and: its carrier: to..-a" substantiallythigheri' de gree than possiblein: the. prior: assemblies em"- playing; a: beveled. retainingxring; especially de"--' a si ned forsuch purpose, i. e; a: tapered ring 'li'a ing. a: bevel;v face along: its: groove seating= edge and; which functions: as 1 an wedge: in: its. groove, so. as toapply' an. axial force; on; the-machine: part abutted: thereby; Due to the. modest groove? depth required for such: aring the fact that:

the angle; of facer'bevelmust not exceed "15" for" security reasons; the capacity of 1 a1 tapered ringt of approximately l ""free diameter toltak'e u'l end. play does: not exceed: .0051 J and. forsmaller ring'dianleters this capacity decreases still fur'a them: to the: point. of:being:practical1y: negligible,

with the-:result: thatzeven: theit'a'pered rings of thebeveled type aforesaidtisiefiective"to takezup but a: fraction; of the totalzend playf likely. 'tot'befe countered in. retaining; ring rassemblies'ir In:sh'arp contrastthereto; the improved retaining ring: as; a sembly; of the-invention, due: to use'therein offa: coiled-wire: retaining, ring and. accompanying-' novel structureand? relationship: Ofi thei parts making. up :the same, .has: the: capacity. of: taking;-

3 up the total of the end play occurring or likely to occur in such assemblies.

The above and other objects and advantages of the invention will be seen from the following detailed description taken with the accompanying drawings, in which:

Figs. 1 and 2 are partial plan and end views, respectively, of a straight length of helically coiled wire of round section from which a coiled wire retaining ring as shown in Fig. 3 is fashioned;

Fig. 3 is a plan view of an external coiled wire retaining ring according to the invention.

Fig. 4 is a side view, partly in section, of a retaining ring assembly of the invention consisting of carrier shaft, coiled wire retaining ring, and machine part located by the latter, the view illustrating the manner in which the retaining ring is capable of taking up end play of the machine part; and

Fig. 5 is a similar view illustrating another form of retaining ring assembly employing an internal ring and the manner in which an internal coiled wire ring may be employed to take up end play of the machine part located thereby in a carrier housing.

Referring first to Figs. 1, 2 and 3 of the drawings, illustrating an external ring employed in one form of improved retaining ring assembly of the invention, such retaining ring, as distinguished from the prior retaining rings of solid section, is of preformed coiled wire construction, being preferably fashioned from a straight length of helically coiled wire I0 (Fig. 1) having-an appropriate number of windings, which is bent to open-ended ring or annulus form H (Fig. 3) of predetermined, constant radius, with its free ends I2, I3 defining a small-width gap 14. Following bending to ring form, the coil is heattreated, i. e., hardened and tempered, with the result that the coil maintains its annular or ring shape in which it is unstressed, having a free diameter which is calculated to be considerably smaller than the diameter of the bottom of the semi-circular groove of the shaft on which the ring is to be assembled. The ring under consideration, being of the external type, may be assembled as usual or it can be spread over the shaft directly in the plane of its groove and released to seat in said groove. Due to the smaller free diameter of the ring relative to groove diameter, the ring is spread or expanded when seated, the gap [4 between the free ends l2, l3 increasing in width according to the shaft diameter. Accordingly, the ring exerts considerable pressure against the bottom of its roove due to the spring temper imparted to it, with the result that the ring securely seats itself when assembled. Preferably, the depth of the groove is such that when the ring is seated, it protrudes from the shaft circle for approximately half its winding diameter, thus forming an artificial shoulder on the shaft capable of locating and securing a machine part against axial displacement thereon.

It is obvious that the degree of spreading that such a ring can take if dimensioned correctly is very large. By "dimensioned correctly is meant the correct determination of the number of windings, the cross-section of the wire '(its diameter in case of a round wire) and the mean diameter of the windings for the required degree of spreading (in case of the externalring) or contracting (in case of the internal ring). If so dimensioned, the working stresses cannot exceed the yield point of the coiled wire making up the ring so that the danger of permanent set is eliminated, on the one hand, while, on the other hand, sufficient seating pressure of ring against groove bottom may be achieved.

The above referred to internal ring, which is adapted to seat in a, groove provided in the bore wall of a carrier housing, follows the construction of the described external ring. However, in the case of the internal ring, it is formed with a free diameter which is larger than the diameter of the bottom circle of the housing bore groove, and hence has a wide gap between its open ends so that the ring can be contracted in assembly and disassembly, and in assembly may expand to seat with spring pressure in its groove. This seat pressure and the degree of contraction that the coiled-wire internal ring can take depends on the correct dimensioning of the ring, as outlined above in connection with the external coiled-wire ring.

An assembly employing a retaining ring of the invention in either the external or internal form may result in end play between the retaining ring and the machine part located thereby, which end play may reach the sum total of the tolerances in the overall length of the machine part, the winding diameter of the ring and the axial location of the groove in shaft. The combined tolerances aforesaid can be considerable and may exceed the allowable end play, and there are also other applications which allow no end play. To deal with this problem, the invention provides a novel form of assembly designed to positively take up end play, which is illustrated in Fig. 4 for the external ring, and in Fig. 5 for the internal ring.

In Fig. 4, an external coiled wire ring 32' as shown in Fig. 3 is seated in a groove 33 provided in the ring carrier such as shaft 34. The shaft groove 33 is formed with an inclined (conical) ring-engaging outer wall 33a which is a section of an elongated cone having a cone angle 9 with respect to a normal to the shaft axis, and terminates in a rounded edge 35 forming a groove inner wall. A machine part 36 located by the ring is provided with a cone-like ring-abutting surface (chamfer) 31 having a cone angle a. with respect to the aforesaid normal and which is smaller than the cone angle ,9 of cone 33a. The difference between angles 5 and a has to be so chosen that under thrust of the machine part 38 against ring 32, the ring cannot slip out of its groove but, instead, locks itself under friction between the abutting conical surfaces 33a and 31. This difference is calculated as follows: if the. friction coeflicient a is larger than the value tang 2 no slipping of the ring along the cone surfaces 33a and 31 can occur under any thrust. Assuming equals .12, which is a fair value for friction of metal against metal, then should be smaller than .12;

tan

ing diameter reach the totalsuch that machine part in relation to the groove takes the position,

groove'and abuts against conesurface :3] of the machine-part.

In Figi5i'the same result of ring taking up end play is achieved by the internal coiled wire ring 42 seated in a groove 43 of a housing 44, the ring providing an internal shoulder for locating a machine part 46. The housing bore groove 43 is provided with a conical outer wall 43a having a cone angle 5 with respect to a normal to the housing bore axis as in Fig. 4, and the abutting or overhanging face of the machine part 41 having a cone angle a with respect to a normal to the housing bore axis, also as in Fig. 4. The ring 42, in tending to shift on the cone surface 43a of the groove, is capable of taking up end play to the sum total of the aforesaid tolerances, as with the external ring assembly of Fig. 4.

The axial end play that the rings 32 and 42 can take up is determined by the winding diameter of said rings, the angle of inclination of groove wall (33a and 43a) and the angle of the chamfer (31 or 41) of the machine part. If we assume an allowable outermost position of said rings, corresponding to their full line positions in both Figs. 4 and 5, and an innermost position as indicated in dotted lines, then the vertical difference between outermost and innermost positions can be easily held to of the winding diameter. Accordingly, the axial end play the ring can take equals %d (tang. 8-tang.a). Thus, if the winding diameter is in., the angle [3:602 the angle a=43, then the end play could be .089. For a shaft of l in. diameter, the end play to be taken up by a coiled wire ring of the invention, seated in a conical-wall groove and abutting against a conical surface (chamfer) of the machine part to be located, would be a multiple of (in the example, approximately 16 times) the end play a tapered split ring of solid section can take up. This property makes such a ring, which according to the difierence between angles 18 and a as above is always self-locking, an especially capable substitute for threaded bolts and nuts subject to end play.

We are aware of the fact that closed coiled wire rings, 1. e. full circular rings, are known as retaining rings, but such closed rings have a distinct disadvantage for use in retaining ring assemblies, as compared with split or open-ended coiled wire rings as herein proposed. In the first place, the allowable degree of spreading or contracting, measured in percentage of diameter change, is considerably smaller than can be achieved with the present open-ended ring, being smaller in approximately the same ratio as the capacity for deformation is smaller in closed solid rings than in split retaining rings of solid section. Secondly, the prior closed coiled wire ring is open to the objection that it tends under thrust to roll over the shaft with very diminishing friction rather than to slide along the surface of the shaft. This property makes the closed coil wire ring insecure under thrust, even when it is seated in a relatively deep groove. Such unfavorable rolling effect under thrust cannot occur when a coiled wire, split or open-ended ring is used in the retaining ring assemblies according to the invention, because there is no transmission of 'torque at its freerends; a fact which'has been verified in tests made by us on both external and internal coiled wire .rings of the present open 'ended typ'e.

Without further analysis, it will be appreciated that the use of a split, coiled wire ring in assemblies and accoi'ding'tot-her'elationship of this present invention achieves ,theobjectives set forth in the foregoing. When properly @dimen sioned, such a ring may have a spreading or contracting capacityof "100% of 'its'" diameter, instead'o'f from 10-14% as in'the case of' prior tapered rings of solid section, without the danger of the ring taking a permanent set. The openended coiled-wire ring may be readily assembled and. disassembled by hand, because the forces required for this purpose are relatively small as compared with conventional retaining rings, such a ring at the same time being capable of exerting adequate pressure against the bottom of its seating groove as required for security under thrust. Moreover, the open-ended coiled-wire ring may be more easily assembled than the conventional retaining rings of solid section and, due to its high allowable spreading capacity, may be assembled on its shaft by spreading the same over the shaft directly in the plane of its seating groove. Also, in assemblies of the invention which employ the improved coiled wire ring of the invention, the ring is capable of taking up a multiple of the end play that can be taken up by prior tapered rings acting on awedge, this in addition to its substantially greater spreading capacity and materially lower force required for its deformation.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. A retaining ring assembly including a machine part carrier provided with an annular groove having an outer conical wall, a machine part carried by said carrier and positioned with an end face overhanging the inner wall of said groove, said end face having a conical surface, the conical outer wall of the groove and the conical surface of said end face providing ring seating and ring abutment surfaces, respectively, and a retaining ring seating on said seating surface and protruding from said groove so as to abut against the aforesaid abutment surface, thereby to locate said machine part and secure it against axial displacement with respect to the carrier, said retaining ring comprising a length of helically coiled wire extending along an arc of substantially constant radius and having its ends spaced from one another, said ring having a free diameter in which said wire is unstressed but being stressed when seated as aforesaid so as to have pressure fit against the conical outer wall of the groove, the inclination of said conical outer wall being such as to cause the retaining ring to tend to slide axially inwardly towards the groove inner wall, and the angle of inclination which said conical outer wall bears to a normal to the axis of the carrier being greater than the corresponding angle which the conical surface of said machine part end face bears to said normal.

2. A retaining ring assembly as set forth in claim 1, wherein the angle of inclination which the conical outer wall of the groove bears to the 7 normal is not more than 15 greater than the Number corresponding angle which the conical surface of 1,810,093 said machine part end face bears to said normal. 2,255,217 HEINRICH HEIMANN. 2,423,848 LAWRENCE BROZEK. 5 7

REFERENCES CITED Number The following references are of record in the file of this patent: 538'821 UNITED STATES PATENTS 247513 Number Name Date Briggs Dec. 24, 1929 Name Date Timson June16, 1931 Hill Sept. 9, 1941 O'Connor July-15; 1947 FOREIGN PATENTS.

Country Date Great Britain Oct. 6, 1902 France Jan, 3, 1940 Germany Nov. 17, 1931 Switzerland Mar. 15, 1947

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