[1]3 1 0 1 1 , 8 0 3 United States Patent Office Patented Dec. 5, 1961 3,011 ,803 SWI VEL CONDUIT JOEI;T Wilb ur G. Buckner, Los Angeles, and Norris J. Brown, ]Ingl ewood, CaHf., assignors to Dumont Aviation Associate s, Long Beach, CaUL,-a corporation of Califomia 5 Filed Jan. 31, 195t, Se.-. No. 712,397 4 CUms. (Cl. 285-23) This invention relates to rotary joints for pipes, tubing, hose , and ,he like, and particularly relates to a swivel joint 10 for high pressure fluid systems such as hydraulic systems. The type of rotary joint to which the invention pertains com prises an inner passage body telescopicahy journaled into an outer passage body with annular sealing means emb racing the inner passage body to @retain the confined 15 fluid. One problem to which the invention is directed is to achi eve an effective seal a.-ainst pressures which may be on the order of 3000 p.s.i. and to do so with freedom for rotati on and with minimum resistance to rotation of the 20 joint structure. This problem is met by employing two coop t-rating sealing n'n.-s in an annular sealing space betwee n the two passage bodies. The annular sealing space is bounded by opposite end surfaces and is @ilso bounded by an inner circumferential surface of the outer passage 25 bod y and an outer circumferential surface of the inner pass age body. The two seaeng rin,-s comprise a first rin- of synthetic resin backed against one of the end surfaces in sealing cont act with both of the circumferential surfaces of the 30 two passage -bodies, and a second deformable. rin.- of rubb er-like material exposed to the internal fluid pressure to be driven thereby a.@ainst the first ring. The first ring, whic h is in seaeng contact with both of the passa,-e bodies, is made of a synthetic resin having a low,coefficient of 35 fricti on in contact with metal. The first ring is of Lshap ed configuration in radial cross section io form an annu lar seat for the s-.cond rin,-. Thus the first rin.- has a radially ex@ending flange portion backed against the end wall of the annular sealing space and has an axially ex- 40 tendi ng Range portion that embraces thd inner passage bod y and extends towards the inner end of the inner passage body. The second ring is positioned in the an.1 - e form ed by these two flanges. Anot her feature of the invention is the cencept Of tape ring the axial fian-,e of the first sealing rin.- to form a 45 prog ressively r@-stricted annular wedge space into which the second rin.@ is forced by fluid pressure. In the prefeiied practice of the invention, the second ring fits tightly arou nd the axial flange of the first ring and re siliently '50 resis ts climbin.- the tapered surfac-es of the axial flange whe n the fluid pressure tends to make it do so. Preferably ,the second rin.- has an unrestrained radial dimension grea ter than the radial space that is prc>vided by the tape red sui-face of the axial flange of the first ring. . 5 5 Anot her problem to which the invention is directed is tb provide a sw--'vel joint of the character described betivee n two coaxial passage bodies with effective yielding resis tance to lateral forces that tend to swing the two passa.-e bodies out c>f axial aligmment with each other. This 60 prob lem is met by providing a ball bearing to serve as a Lulc rum for moments of force that tend to 'rock the. two pass a-e bodies out of axial alignment with each other, and by further employing a relatively long bearing sl6eve of sulita ble low iriction plastic material to resist such 65 mom ents, the length of the sleeve being -more than oneha@ 'f of its outside diameter. ILn the preferred practice of the invention the two teles@e oped passage bodies foriii an annular space surroundi-rg the inner passage body which space is divided by annular I means into a sealing space and a bearing space. The two TO above-inentioned seii@;g rings are in th @e sealing space and 2 the ball bearing together with the low friction plastic bearing sleeve are in the bearing space. A third problem to which the 'mventiou is directed is to provide a swivel joint having these features in which the ball b@earing serves as positive means to interlock the two passage bodies against axial separation and in which the positively acting ball bearing may be rea&-'Iy assembled in the course of fabrication of the swivel joint. In this regard a feature of the invention is the concept of utilizing the low friction plastic bearing sleeve for yieldingly retaining the bafls of the bearing in their assembled positions before the baR bearin.- is completely assembled. For this purpose the inner race of the ball bearings comprises a peripheral circumferential groove formed in the inner passage body and the outer race is provided by two ring mi&mbers which cooperale to form an outer annular@ groove for the balls. The groove around the inner passage body and one of the two rings are so dimensioned and formed that when this one ring is in its normal position, it cooperates with the peripheral groove of the inner passage body to lock the balls in their assembled position. The plastic bearing sleeve is longitudinally resilient and yieldingly maintains this one ring in its normal position. -Thus it is merely necessary to retract this one of the two bearing rings axially against the resistance of the resilient plastic bean'ng sleevb to make the peripheral groove of the inner passage body accessible for the introduction of the bearing balls. A-fter the bahs are installed the ring is released for return to its normal position by the resitient plastic bearing sleeve to retain the balls in the peripl.eral groove. Tle various features and advantages of the invention will be apparent from the following detailed description considered with the accompanying drawings. In the drawings, which are to be@ Tegarded as merely illustrative, FIGURE I is a longitudinal sectional view of a selected embodiment of the invention as a straight swivel joint; FIGURE 2 is an enlarged portion of FIGURE I show.; ing how the plastic bearing sleeve is related to a surrounding spacer sleeve and an annular means that abuts one end of the sleeve; FIGURE 3 is an enlar d portion of FIGU ge 1 showing the two sealing rings in the annular sealing space under conditions of relatively low fluid pressure; FIGURE 4 is a view siniilar to FIGURE 3,, shpwing the two sealing rings under high fluid pressure; FIGURE 5 is a view par-tly in side elevation and partly in longitudinal section showing the partially a@sembled =joint ready for the introduction of the balls of the aringlFIGURE 6 is a view similar to FIGURE, 5'showing, how a special tool is applied to the partial.ly assembled structure of FIGURE 5 to retract a @bearing ring agalinst the resistance of the plastic bearing sleeve'tq a sufficient degree to permit the introduction of the steel balls@ of the bearing; FIGURE 7 is a view similar to FIGURE 6 with the tool removed and with the plastic bearin@ sleev holdin e 9 the bearing rin in position to tra th balls of the ball 9 I p e bearina for retention of the balls during completion of the assembly procedure; and FIGURE 8 is a longiti@dinal sectional view of a second embodimeiit of the invention in- the form of an angillar @.wivel joint. The first embodiment of @ the invention illustrated. by FIGURES I to 71 comprises an outer,.passage body@, 10, a bushing 12 which may be reg@traed z@s. z@ @part of an 6xtension of the outer passage b6dy, and -@n' inner passage body , J 4 that is tel6scoped , in and jo riialed in the 6iiter 14 @ passage@@b6dy. The@ oiiter.passaki,- body 10, 'which'may be of hexagonal V6riph6ral ,configLii4Tion, nas an iiitemal
[2]8,011)803 3 screw thread 16 for connection with conduit means and is ektemally threaded, as shown, for engagement by the bushing 12. The outer passage body 10 has an axial fluid passage 18 which c ommunicates with the fluid passag6 20 of the inner passage body 14 and is axially aligned .5 t@erew@th. The outer passage body 10 cooperates with the bushing 12 to confine and compress a sealing ring 22 which may b.- made of a suitable rLbber-lPLe material such as Neoprene. The inner passage bbdy 14 may have an ex10 t@rnal screw thread 24 for connection to conduit means and may be formed with a radial flange 25 of hexagonal peripheral confi,-uration. The buter passage body 10 and the inner passage body 14 cooperatein their assembled positiolis to form an an15 nul,qr space around the inner passage body, and this anjiular space is divided by an annular means or dividing ring 16 into an annular bearing space and an adjacent annular sealing space. In this particular construction the annular space that is divided by the ring 26 is bounded by 9,0 two end surfaces and is 'further bounded by an inner circumferential surface of the outer passage body and an outet circumferential surface of the inner passage body. Thus one end of the annular space -on one side of the dividing ring 26 is formed by an inner radial shoulder 28 2,5 of the outer passage body 10 and the end of the annular space on the other side of the dividing rin.- 26 is formed by a second inner radial shoulder 30 of the bushing 12. The annular dividing means 26 is in the form of a metal ring mounted in the outer passa.-e body, the metal ring 30 being Tigidly clamped in its assembled position by the bushing 12. The annular bearin.- space between the dividing rng 26 and the inner radial shoulder 28 is occubied by a bearing assembly comdnsing a series of steel balls 32, a: pair 35 of abu@tting bearing rings 34 and 35, a low friction plastic bearing sleeve 36, and a metal spacer sleeire 38. As inay be seen @in FIG.@, 1, the low friction plastic bearing sleeve 36 is in I the same radial zone as the ball bearing @ comprising 'the steel balls 32 and the bear 40 ing rings 34 and 35, i.-e., the plastic sleeve lies within the inner and outer circumferences of, the ball bearing. The bearing@rijig 35 abuts the previously meniioned inner radial shoulder 28; the bearing ring 35 abuts the bearing ring 34;,the spacer sleeve 38 abuts the bear'ng 45 ring 34 and is formed oiff the @ame end with an inner radial flange @40 that abuts the corresponding end of the plastic bearing sleeve 36- and the second end of the astic bearPi ing sledve abuts the dividing ring 26. As shown in FIGURF- 1, the dividing ring 26 is tinder-0 a tut to receive th6 end &f the -plastic b@-aring sleeve 36 and the spacer sleeve 38 that surrounds the bearing terminates short- of the dividing r-ing 26 to form wi-th an annular clearance space 42. It is apparent that @this bearilfg assembly is confined between the inner radial 55 shoulder 28 and the dividing ring 2,6 to keep the bearing tight, the two bean'ng rings 34 and 3@ being clamped between the inner radial shoulder 28 and the spacer sleeve 38. It is further @ppa nt that if there is freedom for the re 60 jploistic bearing @leeve 36 to increase in thickness in re@ponse to axial compression. the bearing assembly may ble contracted axially -a@gains't t]@e Ylelding resistance of the plastic bearing sleev e,:such contracti6n being limited to the axial dimension of the annular clearance space 65 42. As may be- seen in FIGURE 2, preferably the inner di@Lmeter of the resilient beaiing sleeve 36 is sli.-htly larger, than the adjacent diameter of the inner passage body 14 to I provide a slight circumferential clearance space 44. Ile radial@ dimension of this clearance space. 70 second s e al in g ri n a 4 8 is di st o rt -d in to in ti m at e v oi dfr e e 4 4 m a y, fo r. - 6 k a m pl e, b e a p p r o xi m at el y .0 0 1 @ iii c h. It pressure contact with bofh the' first sealing ring 46 and is a-ls6 to be n6i6d in FIGURE 2 that the insid& diameter the inner circumferenti al surface of th6 bushing 12 the of the dividing i7'ng 26 is even larger than the diameter selcond sealiti@ ring:@bcing wedged pqmpactly int6 its seat, of the innir passage - body 14- to provide a dircumferenti al as sho@vn in, FIGURE 4. The greater the internal fluid tlearance@ spae6 45 -6f dven gre-ater radial dimensio@. Th 75 -pressure, th6 great er the sealing@'pressure of the s@cond radial dimension of the clearance space 45 may, for example, be .005 inch. Suitable sealing means is mounted in the annular sealing space defined by the dividing,rin 26, the inner 9 radial shoulder 30, the inner circumferential surface of the bushing 12 and the peripheral circumferential surface of the i@iner passage 1-4@ in thi-S particular embodi'ment of the invent@ion, the sealin.- means comprises a first sealing ring 46 and a second sealing ring 48 coopeirating therewith. The first sealing ring 46 is made of suitable plastic material, preferably a inaterial that has a high-resistance to heat as well as a low coefficient of frictionwith respect to the adjacent nietal surfaces. In this instance, it is contemplated that the flrst sealing ring 48 wifl be made of poly-tetraduoroethylene, com-.ionly available@ under the tradename Teflon. The second sealing ring 48 is of rubber-like, yielding material and, in this instance, is a ncoprene 0-ring. As may be se,-n in FIGURES 3 and 4, the first sealing ring 46 is of L-shaped radial cross-sectional configuration to form an angular seat for the second sealing ring 48. Thus, the frst sealing ring 46 has a radial flan.-e 50 that backs a.aainst the radial shoulder 30 of the annular sealing space and has. an axial flan.-e 52 that embraces the outer circumferential surface of the inner passage body 14. The axial flan.ae 52 the first sealing ring 46 is tapered, as shown in FIGURES 3 and 4, and thereby forms with the inner circumferential surface of the bushing 12 a tapered annular wedge space for the selcond sealing ring 48. Since the.inner radial shoulder 30 of the bushing 12 @aces toward the inner end of the inner passage body 14, the pressure of the confined fluid presses the first sealing ring 46 agains,t the radial shoulder 30 and also backs the second sealing ring 48 ftgainst the radial flange 50 of the first sealing ring. At,the unstressed configuration bf the first sealing iing 46, its inner diame*ler is sli.-htly less than theldiameter of the inner passa-e body 14. In assembling the se@li@g ring 46, it is temporarily expanded, for example, by means of P taper pin, and then is slipped onto the circumferentlial surface of the inner passage member 14. Subsequently, the expanded sealing ring seeks to return to its normal nner i diarneter and thus embraces the inner passage mem be'r 14 un - der permanent circumferential tension for a snug pressure fit therewith. Prefer @ q@ly the inner diameter of the second sealing ring 4,8 at its unstressed config@iration is approximately the outer diameter of the first si@aling rin 46 at the toe 9 of the axi@l flange 52. When fluid pressure acts on the second sealing ring 48, it shifts up the taper or slope of the axial- flange 52 of the first ring 46 with consequent progressively increasing expansion and circumferential tension for i,ncreasing tight fit around the axial flange. It is also contemplated in the preferred practice of the invention ',hat the radial dimension of the second sealing nng 48 at its unstressed configuration will be slightly greater than the radial dimension of the spac6 provided in ihe angular seat formed by the first sealing rin- 46. Thus @the sec,6nd sealing rin- 48 must be radially compressed out of round to fit into its assembled posftion and, by virtue 6f the taper of the axial flange 52 the second seal. . @in- nng is increasingly compressed radially as it is forced by @ fluid pressure towards the radial flange 50 of the@ first seali@@ ring. Under relatively @ low, or moderate fluid pressure, the secand sealing ring 48 may take a position somewhat like -that,shown in FIGURE 3. Under relatively high fliiid ay fluid pressure of 1500 p,s.i. o pressur6, s r higher,@ the
[3]3,011,803 5 s-.alin.- rihg 48 a,-ainst the surrounding inner - cirdumferent-'al surface of the bushing 12 and the greater the radially inward pressure of the axial flange 52 of the first sealin.- ring 46 against the adjacent circumferential surface of the inner passage body 14. The two seahng rings 46 and 5 48 tend to rem-,un fixed relative to the outer passage body, i.e. the bushin.- 12 that is unitary therewith, the relative rotation occurring betnve@-n the Teflon ring 46 and the inrier passa.-e body 14 that it embraces. The manner in which the described swivel joint func- 10 tions for its purpose may be readi'@Y understood from the foregoing description. The only unyielding metal-toml-tal connection between the outer passage body 10 and the inner passa.-e body 14 is provided by the steel balls 42. Both of the bearing rings 34 and 35 are out of con- 15 tact with the inner passage body 14. ne inner radial flange 40 of the spacer sleeve 38, the dividing ring 26 and the radial flange 54 of the bushing 12 are all of larger inside diameter than the outside diameter of the adjacent portions of the inner passage body 114. Thus, there is nO 20 metal-to-metal inte--ference with any tendency of the two passa-e bodies 10 and 14 to swing out of axial alignment with each other in response to forces acting on the swivel joint laterally thereof. Any such metal-to-metal interference would of course create undesirable frictional re- 25 sistance to relative rotation of the two passage bodies and consequent undesirable wear. All such moments of force, however, are taken by the low friction bearing sle.-ve 36 -vvhich is preferably made of a polyamide that is commonly available under the tradename nylon. 30 The manner in v@hich the bearin.- assembly and especially the resilier.,t plastic bearing sleeve 36 facilitates the assembly oi' th-. device may be understood by reference to FIGURES 5, 6 and 7. The bushing 12, separate and apart from the outer passa.-e body 10, is provided with 35 the 0-rin.- 22 and then is telescoped over the inner passage body 14, with the inner passage body member in upright position as shown in FIGURE 5. The t,,vo sealing rings 46 and 48 are then dropped into the annular sealing space which is then closed by insertion of the dividin.- ring 26. 40 The nylon bearin.- sleeve 36 is inserted into position in abutment against the dividing ring 26, and then the spacer sleeve 38 is telescoped over the nylon sleeve. The bearing rin.- 34 is then added to complete the preliminary assembly shown in FIGURE 5. , 45 The inner passage body 14 is formed with a circumferential groove 55 which is of circular cross-sectional conflguration and serves as the inner race for the bearing balls 42. The tnvo bearing rings 34 and 35 together form a similar groove to serve as the outer race for the boaring 50 balls. Thus the bearing ring 34 in FIGURE 5 is formed with an inner half-groove 56. It can be seen in FIGURE 5, that the weight of the bearing rin- 34 and the spacer slee-,,e 38 is bome by the nylon sleeve 36 and that the nylon sleeve holds the bear- @5 in.- ring 34 at appro-,umately its jiormal pos,' tion at which the half-,-roove 56 of the beanng ring registers with the bearin- groove 55 of the inner'passage body 14. The dedth of the inner groove 55 and the depth of the halfgroove 56 are such that they extend more than halfway 60 around a bearin.- ball 32 and therefore will cause a bearing ball to be trapped in the circumferential groove 55. In ocner words, when the -bearin.- rin.- 34 is at its normal position relative to the circumferential groove 55, the entrance to the bearing groove is less than the diameter of a 6,5 bearing ball 32. The advanla,-e of this arrangement is that the nylpn sleeve 36 resiliently holds the bearing ring 34 in its normal position and the nylon sleeve may be compr.-ssed longitudinally in the manner of a spring for retfaction of the -o bearing rin.- to permit the bearing balls to be ilistalled in &.e peripheral groove .55. After the balls are installed, the b.-aring ring 34 may be released to release t he nylon sleeve 36 from longitudinal compression, whereupon the nylon sleeve expands longitudinally to its normal con- 75 1 6 figuration and thus causes the bearing ring 34 to trap and retain the bearing balls in the peripheral groove 55. FIGURE 6 shows how a tool, generally designated by numeral 58, may be used for the purpose of temporarily retracting the bearing ring 34 against resistance of the nylon sleeve 36 to permit the steel balls 32 to be inserted. The tool 58 has a thick handle or knob 60 which may be of hexagonal peripheral conf-iguration and has a thin Cylindrical wall 62 that is dimensioned to extend into th-@ bushing 12 into screw e-.1,@agement with the bushing. Wnen the prehminary assembly shown in FIGU.RE 5 is completed, the tool 58 is inserted into the bushing 12 and is sp-rewed down. The cylindrical wall 62 of the tool has an inner circumferential shoulder 64 which engages the bearing ring 34 to depress the bearing ring in opoosition to the resilient resistance of the nylon sleeve 36. Just above the inner circumferential shoulder 64, the cylindrical wall 62 of the tool has an aperture 65 large enough to admit the steel balls 32. When the tool 58 depresses the bearing ri,.qg 34 sufriciently to make the peripheral groove 55 of the inner pass@ige body 14 fully accessible for introduction of the steel balls 32, the steel balls are fed into the -roove through the aperture 65 of the tool. When tile desired number ol. balls have been inserted, the tool 58 is unscrewed to permit the resilient nylon sleeve 36 to return the bearing rin- 34 to its normal position at which it traps the steel balls in the circumferential groove 55, as may be seen in FIGLTRE 7. The assembly shown in FIGURE 7 may be handled freely without likelihood of any of the assembled parts becoming separated. It is a simple matter to complete the assembly of the swivel joint by adding the second bearing ring 35 and screwing the outer passa,-e body 10 into its assembled position in sr-renvthreaded engagewent with the bushing 12. The second embodiwent of the invention shown in FIGURE 8 is identical in many of its parts with the first embodiment of the invention, as indicated by the use of corresponding numerals to designate the corresponding parts. This embodiment of the invertion is what may be termed an angular swivel joint since it has a-.i outer passage body 66 with a fluid passage 68 therein that is perpendicular to the fluid passage 20 of the inner passage body 14. It is contemplated that the fluid passage 68 will be formed by a second inner passage body 70 that is journaled in the outer passage body 66 for rotation relative thereto. The outer passa.-e body 66 :is 'lormed w,,'th an anntilar space 72 surrounding the second inner.passage body 70 and the second inner passage body has a pair of diametr, .cal apertures 74 communicating with this space to permit free flow of fluid between th-. two fluid passages 20 and 60. One end of the second inner@passage body 72 is formed with an external screw ' hread 75 for connection to the conduit and is also Lormed -,vith a radial flang.- 76 which may be of hexa.-Onal peripheral confl.-Uration to facilitate rotation by a suitable Nvrench. The second end of the second inner pa@-sage body 70 is of reduced diameter and is provided with an external screw thread to receive a retaining nut 78. @Suitable sealing means are provided around tne second inner passag,- body 70 oropposite sides of the annular space 72 of the outer passage body 66. For this purpose the outer passage body 66 may be provided@ with two spaced inner circumferential - rooves 80 to receive corresponding sealing means. Each of the t-,vo sealing means comprises an inner ring 82 and an oiiter ring 84. The inner sealin.- ring 82 is in the form of a I Teflon band t]@at snugly embraces the second inner passa.-e member 70. outer s-.aling rin.- 84 is an o-,-ing of neoprene that is of a cross-sectional diameter to be flattened under radial compression when.'Lo,,-ced into place. T-hese sealing rings 82 and 84 remain stationary relative to the outer passage body 70.
[4]3,011,808 @7 Our description in specific detail of the two embodiments of the invention will su.@gest varibils chan.-es, substitutions and other departures from our disclosure within the spirit and scope of the appended claims. We
