US3722374A

US3722374A - Segmented retaining ring assembly

Info

Publication number: US3722374A
Application number: US00152660A
Authority: US
Inventors: R Densmore
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-06-14
Filing date: 1971-06-14
Publication date: 1973-03-27
Anticipated expiration: 1990-03-27

Abstract

A segmented retaining ring assembly, in which each segment has a generally L-shaped transverse cross section. Each segment includes first and second normally disposed legs, with the first leg when disposed in a first circumferentially extending groove in a cylindrical shell defining an abutment surface, and the second leg when positioned in a second circumferentially extending groove formed in an end piece assembly serving as an appendage for evenly distributing forces in a radial direction to the shell. The end piece assembly reduces the per unit stress on the shell as the former tends to separate from the latter due to a positive pressure within the confines of the shell. This reduction in per unit stress over prior art means of securing an end piece to a cylindrical shell is achieved by distributing the stresses over a greater area. The segmented retaining ring assembly permits an end piece to be easily mounted on or removed from a cylinder shell, when the shell is of the above described structure.

Description

United States Patent 1 1 Densmore SEGMENTED RETAINING RING ASSEMBLY 22 Filed: June 14, 1971 [21] Appl.No.: 152,660

Primary ExaminerMilton Kaufi'nan Assistant Examiner-Ronald H. Lazarus Attomey-Williarh C. Babcock 14 1 Mar. 27, 1973 ABSTRACT A segmented retaining ring assembly, in which each segment has a generally L-shaped transverse cross sec- I tion. Each segment includes firstand second normally disposed legs, with the first leg when disposed in a first circumferentially extending groove in a cylindrical shell defining an abutment surface, and the second leg when positioned in a second circumferentially extending groove formed in an end piece assembly serving as an appendage for evenly distributing forces in a radial directionto the shell. The end piece assembly reduces the per unit stress on the shell as the former tends to separate from the latter due to a positive pressure within .the confines of the shell. This reduction in per unit stress over prior art means of securing "an end piece to a cylindrical shell is achieved by distributing the stresses over a greater area.

5 9 Drawing Figures I SEGMENTED RETAINING RING ASSEMBLY BACKGROUND OF THE INVENTION 1. Field of the Invention A segmented retaining ring assembly.

2. Description of the Prior Art Prior to the present invention, it has been common practice in hydraulic cylinders and pressure vessels that are defined 'by a cylindrical shell and separate end pieces, to'secure the end pieces to the shell by groove engaging snap rings. Such a construction is undesirable as the stresses arising from pressurized fluid in the cylinder is subjected to pressures of various magnitudes the retaining rings are likewise subjected to stresses that vary in magnitude. Ultimately, the retaining rings as they are stressed at various magnitudes enlarge the widths of the grooves due to abrasive action. The rings 'now become loose in the grooves, and move substantially each time the fluid in the cylinder is pressurized, or the magnitude of the pressure in the cylinder appreciably varied. This movement of the rings accentu-.

ates the stresses to which they are subjected, and to the extent that they will ultimately fail.

The primary purpose in devising the present invention is to supply a segmented retaining ring assembly which when used with circumferentially extending grooved cylinders, and end pieces remains in a fixed non-movable position relative thereto, andpermits easy mounting of the end pieces on the cylindrical shell, as well as the convenient removal of the end .pieces therefrom.

A further object in devising the present retaining ring assembly is to permit the end pieces to be so mounted on a cylindrical shell that when the interior of the shell is subjected to a substantial pressure, the retaining rings cooperate to evenly distribute the forces exerted on the end pieces to the shell, and reduce the per unit stress to which the shell is subjected.

SUMMARY OF THE INVENTION quick and convenient mounting of an end piece on a shell, as well as permitting convenient removal therefrom when desired. A major object of the present invention is to supply a segmented retaining ring assembly of simple mechanical structure, with each segment having a generally L-shaped transverse cross sec tion, and the segments capable of removably-engaging first and second recessed portions in a cylindrical shell and end piece to so support the end piece from the shell that forces resulting from a positive pressure within the shell are evenly distributed to end portions thereof, and the per unit stress to which the shell is subjected being reduced over that which occurs when convenient fastening means are utilized to support the end piece from the shell. 7

Another object of the invention is toifurnish a segmented retaining ring assembly that permits a recessed cylindrical shell and end piece to be easily assembled to define a hydraulic cylinder or pressure vessel, as well as to permit the shell and end piece to be easily separated from one another when itis so desired. A still further object of the invention is to furnish a segmented retaining ring assembly that remains in a fixed nonmovable position relative to the end piece and cylindrical shell with which it is associated even after prolonged usage, and one that has no tendency to widen or enlarge the recessedportions of the endpiece and shell in which it is partially disposed.

BRIEF DESCRIPTION OF ms DRAWINGS FIG. 1 is a combined side elevational and longitudinal cross sectional view of a cylindrical shell and end piece that are removably secured together by a first form of my segmented retaining ring assembly;

FIG. 2 is a transverse cross sectional view of the device shown in FIG. 1 taken on the line 2-2 thereof;

FIG. 3 is an exploded end elevational view of the segmented sealing ring assembly;

FIG. 4 is an enlarged transverse cross sectional view of the sealing ring assembly in a first locking position taken on the line 4-4 of FIG. 2;

FIG. 5 is a second transverse section of the retaining ring assembly in a second position forremovably holding an end piece on an end portion of a cylindrical shell;

FIG. 6 is a combined side elevational and longitudinal cross sectional view of a cylindrical shell and end piece, with the shell and and piece being removably locked together by a second sealing ring assembly as shown in FIG. 8; I

FIG. 7 is a transverse cross sectional view of rthe device shown in FIG. 6 taken on the line 7-7 thereof;

FIG. 8 is an end elevational .view of the second sealing ring assembly; and 1 FIG. 9 is an enlarged longitudinal cross sectional view of the sealing ring assembly as shown in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT The first form of the segmented locking ring assembly is shown in' FIG. 3, and includes first and second arcuate segments 5-1 and 8-2, and a third segment 8-3 which is of substantially lesslength than the segments 8-1 and 8-2. The third segment SP3 serves to lock the segments 8-1 and S2 in position to provide a continuous circular ring assembly as will later be explained in detail.

The segmented ring assembly, referred to as awhole by the latter S, is adapted for removably supporting an end piece A in an end portion of a rigid cylindrical shell B as shown in FIG. 1. The end piece A as shown in FIG, I has a bore 10 extending longitudinally therethrough that is slidably engaged by a piston rod C that has a eye D mounted on one end thereof. The end piece so shown inmerely illustrative of one type of end piece that may be removably secured to the shell B by the retaining ring assembly S. If desired, the end piece A may be solid and have no bore 10 formed therein.

The cylindrical shell B as illustrated includes a first end 12, and also a cylindrical surface 14 formed in the interior thereof that defines a longitudinally extending confined space 14a. The shell B adjacent the first end 12 thereof has a circumferentially extending groove 16 therein. The groove 16 extends outwardly from the interior surface 14 of shell B.

The end piece A is of cylindrical shape and includes a first cylinder portion 18 hat has an external surface 20 that snuggly and slidably engages the interior surface 14 of shell B. The end piece A also includes an outwardly disposed second cylindrical portion 22 that has an external surface 24 that is slightly smaller than the diameter of the internal surface of the segmented retaining ring s.

The first portion 18 and second portion 22 of the end piece A defines a circumferentially extending body shoulder 26 at their junction as shown in FIG. 1 First portion 18 of the end piece A has a circumferentially extending first groove 28 formed therein that is engaged by an O-ring 30, which O-ring is in sealing contact with the interior surface 14 of shell B. The second portion of the end piece A has a second groove 32 formed therein that extends outwardly from the bore 10, and the groove supporting a resilient sealing ring 34 that is of a type to prevent escape of fluid under pressure from the space 14a of the shell B, by the fluid flowing between the external surface of the piston rod C and the surface of the end piece A defining the bore 10. To permit hydraulic fluid to be discharged into or out of the confined space 14a, the shell B has a transverse bore 36 therein that is aligned with a tapped bore 38 formed in the first end piece portion 18. Each of the segments -1, 8-2 and 8-3 is of transverse L-shaped cross section and includes a first leg 40 and second leg 42 normally disposed thereto. The legs 40 are adapted to be removably disposed in the groove 16, when the segments 8-1, 8-2 and 8-3 are disposed between the end piece A and shell B as shown in FIGS. 1 and 2. In FIG. 4 it will be seen that the first leg 40 of each of the-segments 8-1, 8-2 and 8-3 is disposed in the groove 16, and the second leg 42 being situated in the space to the left of the groove as viewed in FIG. 1

that is situated between the interior surface 14 of the shell and the external surface 24 of the second portion 22 of the end piece A.

The second leg 42 serves as an appendage to circumferentially and evenly distribute stresses from the segments 8-1, 8-2 and 8-3 to the interior surface 14 of the shell B to the left of the first legs 18 as viewed in FIG. 1 when the end piece A is in position in the shell, and the interior of the shell is subjected to a positive pressure. The retaining ring assembly S when disposed in the first position as shown in FIG. 4 has circumferentially extending abutment surfaces 40a thereof in contact with the first circumferentially extending surface 160 of the grooves 16 as shown in FIGS. I and 4. The abutment surface 40a serves to prevent the end piece A from moving to'the left as viewed in FIG. 1 when the space 16 within the shell B is subjected to a positive pressure.

The sealing ring assembly S is positioned within the grooves 16 by moving the end piece A to the right to the extent that the first legs 40 of segments S1 and 8-2 may be inserted within the grooves 16. When the segments S-1 and S2 are so inserted, they are moved to have the end surfaces 44 placed in abutting contact. The third segment S-3 may now be slid into the space between the ends 46 of the segments 5-1 and 8-2 and serve to lock them in retaining positions. When the third segments-14 is so disposed, the end surfaces 48 thereof are in abutting contact with the end surfaces 46 of the segments S4 and S2.

The end piece A may now be slid to the'left as viewed in FIG. 1, and with the body shoulder 26 thereof now in abutting contact with the circumferentially extending surface 16b of the segments 8-1, S2 and g The second portion 22 of the end piece assembly has a third groove 50 formed in outer portion thereof and so situated that when a snap ring 52 is caused to engage the third groove, the snap ring is in abutting contact with end surfaces 54 of the second legs 42 as best seen in FIGS. 1 and 4. The snap ring 62 prevents the end piece A being inadvertently moved to the right when disposed in the cylindrical shell B as shown in FIG. 1.

The depth of the first groove 16 is preferably onehalf of the thickness of the side wall of the shell 13, but it is not limited to this particular depth. When the end the radial distance from surface 14 to the surface 16c of.

groove 16 is less than the radial distance from the surface 14 to the surface 24, the segments S-1, S-2 and 8-3 will tend to pivot in adirection where the legs 42 thereof tend to move away from second position 22, with the pivot line being identified by the numeral 56 in FIG. 4.

The stresses from fluid under pressure in the space 14a is transferred not only to the shell B through the surface 16a, but also through the surface 14 to the left of the first legs 40 as the second legs 42 tend to pivot away from the second portion 22 of end piece A. Should it be desired, the outer extremity of the end piece A may have a fourth circumferentially extending groove 58 formed therein, which groove engages a resilient washer 60 that is in slidable sealing contact with the piston rod C, and tends to prevent dust, grit or the like that adheres to the piston rod to the left of the end piece A as viewed in FIG. 1 from being carried intothe confines of the end piece and abrading the interior surface thereof. In FIG. 4 it will be seen that the groove 16 need not be of the precise size of the first leg 40, but may have a tapered interior end surface 16b.

The retaining ring structure may be utilized in the second form shown in FIG. 5 to accomplish the same results as achieved when assembled in the first form as illustrated in FIG. 4. In the second form, the surface 40a of the second leg.40 is in abutting contact with the surface 16a of the groove 16. The retaining ring assembly A when assembled in the second form as shown in FIG. 5 serves the same purpose as when assembled in the first form as illustrated in FIG. 4. The end piece A as shown in FIG. 1 has a longitudinally extending passage formed therein that is in communication with the tapped bore 38, to permit hydraulic fluid under pressure to be discharged into or out of the space 144.

Upon occasion, it may be desired to mount an end piece A as illustrated in FIG. 6 on the exterior surface of a cylindrical shell B and for that purpose the retaining ring structure S as illustrated in FIG. 8 is employed. The retaining ring structure 8' includes at least two arcuate segments 72 of the same general structure. Each of the segments 72 includes a first leg 74 and a second leg 76 normally disposed thereto as shown in FIGS. 6 and 9.

A cylindrical end piece A is provided as shown in FIGS. 6 and 7, and is illustrated as having a bore 78 extending longitudinally therethrough that is slidably engaged by a piston rod C. The end piece A if desired may be of solid structure, and not include the bore 78. The end piece A has first and

second grooves

80 and 82 extending outwardly from the interior surface 86 thereof, and the

grooves

80 and 82 housing resilient

circular sealing members

88 and 90 as shown in FIG. 6. The end piece A has a transverse tapped bore 92 formed therein that is in communication with a longitudinally extending passage 94. The passage 94 is in communication with the interiorly disposed annulus-shaped passage 96 defined between the exterior surface 78 of the piston rod and the interior surface 98 of the shell B. i

The shell B adjacent a first end 100 thereof has a longitudinally extending groove 102 formed in the external portion thereof. The first legs 44 of the retaining ring assembly S may be disposed in the groove 102 and the end surfaces 72a of the segments being in abutting contact. The end piece A includes a first cylindrical portion 104 that has threads 106 defined on the exter- .nal part thereof to the right of the tapped bore 92 as shown in FIG. 6. The end piece A also includes a second cylindrical portion 108 that is of smaller diame ter than the first portion, and the exterior surface 110 of the second portion being such as to snuggly and slidably engage the interior surface 98 of the shell B. A third circular recess 112 extends inwardly into the second portion from the surface 1 thereof, and is occupied by a resilient sealing member 114.

The segmented retaining ring assembly S is removably held in the locking position as shown in FIG. 6 by a cap 118 that is internally threaded, and removably engages the threads 106. The cap 118 includes an inwardly extending circular flange 120 that abuts against the surfaces 122 of the retaining ring assembly S as shown in FIG. 9. When the confined space 96 is subjected to fluid under pressure, the end piece assembly A tends to move to the left, but is prevented from so doing due to the cap 118 interlocking with the sealing ring assembly S. The stresses to which the end piece assembly A are subjected are transferred through the cap 118 and flange 120 to the retaining ring assembly S, which assembly in turn transfers the stresses to the circumferentially extending surface 124 that partially defines the groove 102. The sealing ring assembly S permits the I end piece A to be easily mounted on or removed from the cylindrical shell B by unscrewing the cap 1 18 therefrom or screwing the cap thereon as the case may be. i

The use and operation of the invention has been previously explained in detail and need not be repeated.

Although the invention has been described in conjunction with a cylindrical shell that is subjected to a positive pressure within the interior thereof, it will be apparent that the retaining ring assembly may be used equally well on a cylindrical shell to removably maintain end pieces in position on either one or both ends thereof.

I claim: j

' l. A hydraulic cylinder assembly of the type that includes a rigid shell having an open end and a cylindrical interior surface, an end piece having a longitudinal bore therein in which a piston rod may be slidably positioned, and a longitudinally extending passage coaxial with said bore and of a larger diameter than said bore, said end piece having a circular transverse cross section that includes a first portion that slidably and sealingly engages said interior surface and a second portion of smaller transverse cross section than said first portion and coaxially aligned therewith, said first and second portions at their junction defining a ring-shaped body shoulder that is of a first width, with said hydraulic cylinder assembly characterized by a retaining ring that is so operatively associated therewith that when all of said first portion and at least a part of said second portion are within the confines of said shell and the interior of said shell is subjected to pressure the force exerted on said end piece is distributed both longitudinally and radially on said shell, with said retaining ring being of transverse L-shaped cross section and including first and second legs of rectangular shape, said retaining ring being defined by at least three sections that may be assembled within said shell adjacent said open end for said first leg to extend into a circular groove in said shell adjacent said open end that extends outwardly from said interior surface for a first ringshaped surface of said first leg to abut against a. first ring-shaped surface that partially defines said groove and a portion of a second ring-shaped surface of said first leg to abut against said body shoulder, said first ring-shaped surface of said groove closer to said first end than said second ring-shaped surface of said first leg, said portion of said second ring-shaped surface of greater width than the width of said first ring-shaped surface, said second leg of the assembled retaining ring extending towards said first end and encircling said second portion, said second leg having a first outer surface in contact with said interior surface of said shell, and said end piece when subjected to pressure within said shell tending to move toward said first end and in so doing tending to force said sections of said retaining ring to pivot in a direction that a portion of said force is distributed longitudinally to said shell due to said first surface of said first leg bearing against said first surface of said groove and the balance of said force being distributed radially to said shell by said first. outer surface of said second leg bearing against said interior surface of said shell.

2. A hydraulic cylinder assembly as defined in claim 1 which in addition includes:

a. first means for maintaining said end piece in a Sta tionary position relative to said retaining ring when the interior of said shell is not subjected to pressure.

3. A hydraulic cylinder assembly as defined in claim 1 in which said first means is a snap ring that is removably seated in a second circular groove formed in the exterior surface of said shell, and said second groove so disposed that said snap ring abuts against the outermost portion of said endpiece.

4. A hydraulic cylinder assembly as defined in claim 2 inwhich said end piece has sealing means mounted thereon that slidably engage said piston rod.

5. A hydraulic cylinder assembly as defined in claim 1 in which said first portion of said end piece has a first transverse circular groove on the exterior surface thereof, and said cylinder assembly further including:

a. a resilient sealing ring mounted in said first groove 5 and in pressure sealing contact with said interior surface.

Claims

1. A hydraulic cylinder assembly of the type that includes a rigid shell having an open end and a cylindrical interior surface, an end piece having a longitudinal bore therein in which a piston rod may be slidably positioned, and a longitudinally extending passage coaxial with said bore and of a larger diameter than said bore, said end piece having a circular transverse cross section that includes a first portion that slidably and sealingly engages said interior surface and a second portion of smaller transverse cross section than said first portion and coaxially aligned therewith, said first and second portions at their junction defining a ring-shaped body shoulder that is of a first width, with said hydraulic cylinder assembly characterized by a retaining ring that is so operatively associated therewith that when all of said first portion and at least a part of said second portion are within the confines of said shell and the interior of said shell is subjected to pressure the force exerted on said end piece is distributed both longitudinally and radially on said shell, with said retaining ring being of transverse L-shaped cross section and including first and second legs of rectangular shape, said retaining ring being defined by at least three sections that may be assembled within said shEll adjacent said open end for said first leg to extend into a circular groove in said shell adjacent said open end that extends outwardly from said interior surface for a first ring-shaped surface of said first leg to abut against a first ring-shaped surface that partially defines said groove and a portion of a second ringshaped surface of said first leg to abut against said body shoulder, said first ring-shaped surface of said groove closer to said first end than said second ring-shaped surface of said first leg, said portion of said second ring-shaped surface of greater width than the width of said first ring-shaped surface, said second leg of the assembled retaining ring extending towards said first end and encircling said second portion, said second leg having a first outer surface in contact with said interior surface of said shell, and said end piece when subjected to pressure within said shell tending to move toward said first end and in so doing tending to force said sections of said retaining ring to pivot in a direction that a portion of said force is distributed longitudinally to said shell due to said first surface of said first leg bearing against said first surface of said groove and the balance of said force being distributed radially to said shell by said first outer surface of said second leg bearing against said interior surface of said shell.

2. A hydraulic cylinder assembly as defined in claim 1 which in addition includes: a. first means for maintaining said end piece in a stationary position relative to said retaining ring when the interior of said shell is not subjected to pressure.

4. A hydraulic cylinder assembly as defined in claim 2 in which said end piece has sealing means mounted thereon that slidably engage said piston rod.

5. A hydraulic cylinder assembly as defined in claim 1 in which said first portion of said end piece has a first transverse circular groove on the exterior surface thereof, and said cylinder assembly further including: a. a resilient sealing ring mounted in said first groove and in pressure sealing contact with said interior surface.