Патент USA US2127928код для вставки
v Aug. 23, 1938. T. E. MODOWELl.‘ PLUG AND RECEPTACLE Filed May 24, 1957 3 She_ets-—Sheet 1 Aug. 23, 1938.~ 2,127,928 'r. E.’ McpowELL. PLUG AND RECEPTACLE- Filed May 24,’ 1957 . 3 Sheets-Sheet 2 Aug. 23, 1938, T, E, MCDOWELL 2,127,928 PLUG AND RECEPTACLE Filed May 24, 1957 ‘V 3 Sheets-Sheet 3 ZWMEUUH Patented Aug. 23, 1938 2,127,928 UNITED STATES PATENT OFFICE 2,127,928 PLUG AND RECEPTAC‘LE Thomas E. McDowell, Chicago, Ill., assignor‘to The Pyle-National Company, Chicago, 111., a corporation of New Jersey Application May 24, 1937, Serial No. 144,452 .5 3 Claims. (01. 173-332) The present invention relates to plug and re Figure l is an elevational view of a separable ceptacle construction, and more particularly to connector of the present invention with the two improvements in electrical connectors and more parts in connected relationship. particularly to two-part separable connectors of Figure 2 is an enlarged, fragmental, axial sec-e the plural contact type, wherein the parts are tional view through one part of the connector, connected and disconnected by axial movement herein designated as the receptacle. of the parts towards and away from each other. Figure 3 is an enlarged, fragmental, axial sec An object of the present invention is to pro tional view through the other part of the connec vide a two-part electrical connector wherein the tor of the present invention, herein designated insulating bodies carrying the male and female as the plug. contacts may be interchangeably assembled in the Figure 4 is an end view of a receptacle of Fig protective casings of the parts. ure 2, looking at the right-hand end of Figure 2. Another object of the invention is to provide a Figure 5 is a transverse section taken substan two~part electrical connector in which the in tially in the plane indicated by line V-V of sulating contact carrying bodies are formed each Figure 2. of two members, with the bodies secured in place Figure 6 is an exploded view showing a frag in their protective casings by connecting means mental portion of a protective casing, and the between the two members of a body. members constituting the insulating bodies of A further object of the present invention is to the present invention, the parts being in proper provide a two-part electrical connector wherein position for assembly of the body members in the insulating contact carrying bodies are fash their protective casing. ioned each of two members, and wherein the two Figure 7 is a transverse sectional view taken members of a body are clamped about a portion substantially in the plane indicated by line of its casing to prevent separation of the casing " and body. ‘ A still further object of the present invention is to form an insulating body for one part of a two-part separable electrical connector, which body consists of two members, one of which mem .30 bers carries the contacts for said one part, and the other of said members is restrained against displacement with respect to its casing by making shouldered engagement with said casing, and securing said two members together within the 35 casing to clamp them to the shoulder to prevent displacement. The invention has for a further object the provision of a two-part electrical connector con struction wherein the insulating bodies of the 4.0 parts are clamped in place within their protective casings by cooperating parts of the bodies and casings. The invention has for another object the pro vision of a two-part electrical connector con " struction wherein the insulating bodies for the parts are held in place in their protective casings by bolts which do not threadedly engage any part of the casings. - The above, other, and further objects of the present invention will be apparent from the fol lowing description and accompanying drawings. The accompanying drawings illustrate a two part separable electrical connector, constructed in accordance with the principles of the present 55 invention, and the views thereof are as follows; -. 10 15 20 VII-VII of Figure 2‘. Figure 8 is an axial central view of one of the 25 protective casings of the illustrated form of the present invention. Figure 9 is an end view of the casing of Figure 8, looking at the right-hand end of said ?gure. Figure 10 is a transverse sectional view taken 30 substantially in the plane indicated by the line X—X of Figure 8. ‘ The drawings will now be explained. The ‘two-part separable connector illustrated in Figure 1 includes a receptacle A and a plug B. 35 The receptacle A has a protective casing I of the general form and shape illustrated in Figures 8, 9, and 10 and is made of suitable material, such for example as “Bakelite” or any other ma terial suitable for the purpose. The casings of both the receptacle A and the plug B are similar in shape and form and are adapted to interchangeably receive the insulating bodies of the plug and receptacle. Figure 8 illustrates the details of the illustrated 45 form of casing which is made of generally cylin drical form in end elevation, having its rear por— tion of reduced diameter with respect to the front portion. The rear portion is ‘shown at the left in Figure 8, and the front portion is shown at the .50 right in Figure 8. The extremity of the reduced rear portion is threaded at 2 and the entrance end to the rear portion is preferably formed with a frustro conical surface 3 against which the irustro 2 2,127,928 conical outer surface of a bushing 4 bears when the parts are assembled. For retaining the bush ing 4 in position, a strain relief nut 5 having an end wall 6 in which there is the central opening ‘I of less diameter than the internal threads of’ the nut, is threaded on to the threaded portion 2 of the casing and carries a washer 8 which bears against the bushing 4. When the electrical cables G are passed into the ends of 10 the rear portions of the casings, and are suit ably connected to the contacts carried by the insulating bodies, and the body parts are assem bled in operative relationship, the nuts 5 are tightened to thereby compress the bushings 4 15 about the conductors to prevent withdrawal of the cables, and serve as strain relief means for the cables. The casing l is formed with an internal an nular shoulder 9, at substantially the junction 20 between the rear and front parts. A portion of the surface of the interior of the casing is cut away to form an arcuate recess ID the bot tom or inner surface of which is spaced inwardly from the shoulder 9. This recess I0 serves as 25 an arcuate slot in which a tail piece on the inner member of the insulating body works, to limit rotative movement of said inner body, as will be hereinafter more fully explained. The interior of the casing, at its front end is 30 fashioned to provide a plurality of inwardly di rected axially extending tongues ll, l2, and i3. Between the tongues, circumferentially of the casing, are arcuately shaped grooves I4, I53, and Is. As illustrated, the groove M is between the 35 tongues H and I2, the groove l5 between the tongues l2 and I3, and the groove l6 between the tongues 13 and H. The inner extremities of the tongues ll, [2, and I3 stop short of the annular shoulder 8, within the casing, a distance 40 but slightly greater than the axial thickness of a part of an inner member of the insulating body. The inner extremities of the several tongues, constitute what are herein termed as shoulders and are designated at I‘! in Figure 8. 4.5 illustrated in axial section in Figure 2, and in isometric view in Figure 6. Likewise the insulating body for the plug B comprises two members, C and the member C being of the same construction for both the receptacle A and the plug B. The member C, herein termed the “inner” member is of less axial length than either of the outer members D or E of the insulating bodies. Each of the inner members C is formed with 10 radially projecting tongues 69, 2t, and 25 which are circumferentially spaced by axially extend~ ing grooves 22, 23, and 2d. The groove 22 is between the tongues l9 and M, the groove 23 is between the tongues 2D and 2!, and the groove 15 24 is between the tongues 2i and ill. The cir cumferential extent of the tongue 2! of the inner member C is fashioned to slide into the groove M of the casing i. In like manner the tongue l9 of the member C ?ts the groove 56 of the casing, 20 and the tongue 20 fits the groove 85 of the casing. The grooves 252, 23, and 24 of an inner member C receives, respectively, tongues l3, l2, and H of the casing when the inner member C is assembled in its casing. Referring to Figure 6 25 of the drawings, the face of the inner member C which. is readily observed, is for convenience herein termed the outer face. The inner face of each of the inner members C is provided with an axially extending lug 25 which, when an inner 30 member is assembled in its casing, lies within the recess iii of the casing. The relationship of the lug 25 and the inner face of an inner mem ber C, is such that when an inner member is assembled in its easing by axial movement, the 35 lug will lie against the left-hand end of the recess If), as viewed in Figure 10. The outer face of each of the inner members C is provided with outstanding collars 25. there being as many of these collars 26 as there are apertures 2'6’ through the inner members for passage of conductors to the contact members carried by the outer insulating member of a body. Each of the insulating bodies C is pro In order to prevent assembly of an insulating body in its casing in any but the proper relative vided with axially extending, circumferentially 45 spaced apertures 28 which are arranged between angular relationship, the circumferential extent the several collars 26 and conductor apertures of the several grooves as well as the intervening tongues, are different. As illustrated, the cir cumferential extent of the grooves l5 and. I6 is the same, while the circumferential extent of the groove I4 is greater than that of either of the grooves I5 and 16. The circumferential ex tent of the tongue I3 is greater than the cir cumferential extent of either of the tongues H and I2, the tongues H and I2 being of the same circumferential extent. If desired for ease of assembly of the insu lating body members in their casing, one of the tongues, such for example as the tongues l3 may be provided with an axially extending notch l8. When the tongues H are provided with axially extending notches l8, the body members C and 65 D may be provided with projections 62 to inter?t with said notches during assembly of these parts in the shell. Immediately in front of the annular shoulder 9 the interior of the front end of the casing is 70 cylindrical, with a diameter of that of the bases of the several grooves l4, l5, and i5 formed in the front end of the casing. The insulating body for the receptacle A is 75 formed of two members C and D, which are 27 of the member C, for receiving attaching bolts 29. Preferably the insulating bodies C, D, and E 50 are made of moldable material, such for ex ample as “Bakelite”, or other material of suit able nature. At the time the members C are molded, metallic inserts or bushings 3B are mold ed with the members. The interiors of these 55 inserts 3?! are threaded to receive the threaded ends 3| of the bolts 29. The rear face of each of the members C is formed with circular pro jections E32 formed as continuations of the aper tures 23 of the member C, to serve as feet to 60 bottom against the shoulder 9 of the casing when a member C is assembled, as may be readily observed in Figures 2 and 3. The relationship of the conductor apertures 21 in the inner member C, with respect to the 65 relationship of the apertures 32 of the outer member D of the receptacle insulating body, is such that when the inner and outer members C and D, are aligned for assembly in a receptacle casing l, as illustrated in Figure 6, the apertures 70 21 and 32 are out of axial alignment. The inner members C are assembled in their casings by applying these members to the front ends of the casings, with the tongues and grooves in inter?tting relation, and sliding the members 75 2,127,928 C inwardly until the same abut the shoulders 9 of the casings, thereupon the inner members C are given rotative movement clockwise as viewed in Figure 6, and counterclockwise as viewed in Figure 5, until the lugs 25 abut the right-hand extremities of the recesses H), as viewed in Figure 10, which movement brings the tongue 2| of an inner member C under the‘ shoulder ll of a tongue H of the casing, the tongue l9 of the 10 member C under the corresponding shoulder ll of the tongue I3 of the casing, and the tongue 20 under the shoulder I‘! of the tongue I2 of‘ the casing, thereby interlocking the inner members in the casings against axial displacement. 15 The inner members C are rotated so that the lugs 25 thereof rest against the right-hand ex tremities of the recesses IU of the casings as viewed in Figure 10, the conductor openings 21 are then in alignment with the openings 32 of the outer members of the insulating bodies. The member D, of the insulating body for re ceptacle A is likewise formed of moldable mate rial, such for example as “Bakelite”, and in gen eral the surface contour is cylindrical. Formed 25 in the body D, when it is molded, are the contact openings 32, which are angularly spaced and which extend throughout the length of the mem— ber D. In the outer surface of the inner end of the outer member D are formed grooves 33, 34, 30 and 35 which, in circumferential extent, are , adapted to receive the tongues I I, I3, and I2, re spectively, of the casing l of the receptacle, as may be observed in Figure 7. The several grooves 33, 34, and 35 extend part way of the 35 length of the outer member D, terminating in circumferential shoulders 36 which, when the outer member D is assembled in its casing, abut the outer ends of the tongues ll, l2, and I3 of the casing I, thereby limiting the assembled or 40 inward position of the outer member D in the casing. - The inner face of the outer member D is shaped to conform with the outer surface of the inner members C, to receive the collars 26 sur 45 rounding the conductor apertures 21 of the member C. The shape and arrangement of one of the con tact receiving openings 8 is shown‘ in section in Figure 2. 50 An opening H is bored from the inner end of the member D, i. e., left hand as shown in‘ the ?gure, with a series of axially spaced bores 38, 39 and 32, respectively of decreasing diameters in the order shown. 55 ‘ The largest bore 38 receives a collar 26 of the inner member C, when the members are assem bled, the intermediate bore 39 receives the en larged end or head 63 of a female contact F, while spring ?ngers 44 of the contact lie within the bore 32, which is of greater axial length than either of the bores 38 or 39. There is an en trance 3‘! to an opening H, for a male contact, which opening is bored through an end wall 43 at the outer end of the member D. Formed in the insulating member D and dis 65 posed between the opening 32 of the member, are apertures 40 for the attaching bolts 29. The apertures 48] extend axially of the member D. The outer face of the member D is counter 70 bored at 4! to receive the heads 42 of the several bolts 29 and immediately adjacent the counter bores M the body D is apertured and threaded at 64 to engage the threaded ends of the bolts when the bolts are ?rst applied to the member 75 D. Inwardly of the threaded portion 64 the body 3 is bored to provide elongated bolt holes of suffi cient diameter to slidingly receive the threaded ends of the bolts 29 ‘and permit easy movement of the bolts lengthwise of the member D. The purpose of the threaded portions 64 is to prevent .3 loss of the bolts 29 from the member D, when this member is disconnected from the inner body member C. In other words, the bolts 29, when the member D is disconnected from its member C, may slide back and forth in the apertures 43 but cannot fall out of the member because of the fact that the threaded portion of the bolts must be unscrewed through the threaded por tions 64 of the member D before the bolts can be removed. ‘ Within the contact openings H of the member D of the receptacle insulating body, are female contact members, designated generally as F. These contact members F are inserted in the body member D through the inner end of such member, that is to say, from left to right, as viewed in Figure 2. Every one of the female contacts F is provided with split'sleeve portion 44, the outer extremities of which terminate inwardly of the wall 43 de?n- I 25 ing the entrance opening 31. The inner por tions or heads 63 of the contacts F are, exte riorly, fashioned to ?t within the bores 39 and 32 of the contact openings or apertures H, and pref erably with extremities 45 which enter slight dis 1-30 tances into the collars 26 of the inner member C. The inner ends or heads of the contacts F are counterbored at 43 and into these counterbores are inserted‘the ends ill of the individual con ductors G. The conductors G’ of cable are pref erably soldered to the contacts F, thus assuring integral connection and proper electrical connec tion as well. ‘ The outer face of the member D is provided with channels 48 which communicate one with another substantially centrally of the member D, and extends radially outwardly to the counter bores 40 for the bolt heads 42. The purpose of the channels 48 is to prevent such an accumu lation of carbon particles, due to arcing, when vthe parts of the connector are separated, as would otherwise short-circuit the receptacle in sulating body between any two of its contacts F. The‘channels 4B are deep enough, axially of the member D, to prevent carbonization of materials $50 such as “Bakelite”, created by arcing to prevent short-circuiting, for substantially the life of the member D. s ' ' Figure 4 shows the position of the channels 48 with respect to the contact apertures of the mem ber D. In wiring the receptacle A, the bodies C and D are removed from the casing, the conductor cable is inserted through the rear end of the casing, and the individual‘ wires of the conductor sev (50 erally‘ applied to the counterbores 46 of the female contact members F, with these contacts removed from the outer member D. Before the conductors are attached to the contacts F, the wires thereof are passed through the conductor apertures 21 of the member C, which is out of the casing l, during such wiring assembly, and then the contacts F are soldered to the extremi ties of the conductors and the contacts F are in~ serted in the openings H of the member D. Mem 70 ber C is then moved along conductors to butt against end of contacts, whereupon the inner body member C is assembled in its casing I by engaging its tongues and grooves with the grooves and tongues, respectively, of the casing, moving is 2,127,928 the inner member C inwardly until it rests against the shoulder 9, whereupon the member C with contacts is given rotative movement so that its tongues lie under the shoulders ll of the tongues ll, I2, and I3 of the casing I. The member D, is then applied over contacts F by sliding the contacts into the several apertures 32, from the inner end of the body D, as viewed in Figure 2. The outer body member D is then 10 assembled into the casing by sliding it with its tongues entering the grooves l4, l6, and I5 of the casing, and its grooves 33, 34, and 35 receiv ing the tongues l I, I3, and I2, respectively, of the casing, thus properly aligning the outer mem 15 ber D in the casing. The inner member D is moved into its casing I until the shoulders 36 of its grooves abut the outer extremities of the tongues of the casing, whereupon the bolts 29 are threaded into the bushings 30 of the inner 20 member D and tightened to hold the members C and D together. By reason of the fact that portions of the inner member C abut the shoulder I‘! or inner ends of the tongues of the casing and the shoulders 36 25 of the outer member D abut the outer extremi ties of the tongues of the casing, then when the bolts are tightened, the inner and outer insu lating body members are clamped against the ends of the tongues, thereby interlocking the in 30 sulating body in its casing against endwise dis placement. By reason of the fact that the tongues and grooves of the outer member D are in engage ment with the corresponding grooves and tongues 35 of the casing, rotative movement of the outer member with respect to the casing is prevented. Because of the fact that the inner member C is bolted to the outer member D, rotative movement of the inner member is thus prevented so that the insulating body of the receptacle is thus se curely interlocked in its casing against axial dis placement as well as against rotative displace ment with respect to the casing, all without any bolts engaging any part of the casing, thereby 45 eliminating need for precision manufacture of the casing in that respect. Referring now to Figure 3, the outer member E of the plug insulating body has an outer cylin drical surface conforming substantially to the outer diameter of the front end of its casing. The 50 member E is hollow, having a diameter to tele scopically receive so much of the outer member D of the receptacle insulating body as projects beyond the front end of its casing. The inner portion E’ of the outer body member 55 E of the plug, is adapted to rest against the in ner member C of the plug insulating body and its inner face is shaped and fashioned to re ceive the collars 26 of its inner member C, as 60 may be observed in Figure 3. The member E is apertured at 49 to receive pin contacts 50, 5 I. There are, of course, as many pin contacts in the plug as there are female con tacts F in the receptacle. Inwardly of the apertures 49 for the pin con 65 tacts the body member E is enlarged at 52 to re ceive enlarged portions 53 of the pin or male con tacts and thus prevent displacement of the male contacts when the parts of the connector are 70 separated. Arranged between the apertures 49 for the male contacts 50, 5|, the inner portion of the member E is provided with axially extending apertures 6| for attaching bolts 54. The mem 75 ber E is counterbored at 55 to receive the heads 56 of the bolts and to permit these heads to lie inwardly of the adjacent portions of the hollow part of the member E, to prevent possibility of short circuiting. Inwardly of the bores 55 the ‘member E is threaded at 51, for a short distance, with the balance of the apertures 6| of greater diameter, so that the bolts 54 may slide freely within the apertures, when disconnected from the threaded bushings 30 of the member C. The bolts 54 of the plug part function in the v10 same manner as the bolts 29 of the receptacle part, as heretofore described. The members C and E, of the plug part, are assembled as follows: To attach the conductors to the male con 15 tacts 50 and 5|, the bolts 54 are disconnected from the inner member C, the outer member E is withdrawn from its casing, the inner member is then rotated sufficiently to be withdrawn from the casing, whereupon the conductor cable G is 20 then inserted thru the rear end of the casing l of the plug B, with the strain relief nut 5, of course, released, and the wires of the conductor cable passed through the apertures 21 in the member C, and soldered to the enlarged portions 25 53 of the male contacts 50, 5|, which contacts are removed from the outer member E, for the purpose of soldering. After the wires are soldered to the male contacts, the inner member C is moved into its casing I, and given rotative move 30 ment to interlock it under the shoulders H of the tongues of its casing in the same manner as de scribed with reference to the inner member C of the receptacle. The male contacts are then inserted in the 35 member E and the member slid into the casing B until the shoulder 58 abuts the member E, whereupon the bolts 54 are screwed into the bushings 30 of the member C thus securing the members C and E in ?xed relationship in the 40 casing. The outer surface of the inner end E’ of the member E is fashioned with the grooves corre sponding to the tongues II, I2, and iii of the casing, so as to interfit therewith in the same 45 manner as the outer member D of the receptacle insulating body ?ts its casing. The grooves of the member E terminate in circumferentially ex tending shoulders 58 which rest against the outer ends of the tongues ll, l3, and I2 of the 50 casing, when the outer member E is assembled. Thus when the members C and E are assem bled in their casing, and the bolts 54 threaded into the bushings 30 of the member C, the mem bers D and E are clamped against the ends of the tongues ll, [2, and I3 of their casing, to thereby prevent axial displacement of the insulating body with respect to its casing. Because of the fact that the grooves 33, 34, and 35 of the member E interlock with the tongues of the casing l, the 60 insulating body is prevented from rotative move ment with respect to the casing. In order to assure connection of the plug B and the receptacle A, in proper polarity, the outer surface of the member D may be provided with a longitudinally extending groove 59 and the interior surface of the hollow portion of the member E with an axially extending ridge 6!! which enters the groove 59 when the parts are connected. 70 When the parts A and B are connected, as shown in Figure 1, that portion of the member D of the receptacle lies within the hollow por tion of the member E of the plug, in telescoping engagement, with the male contacts 55 and 5| 75 - 2,127,928 entered in the female contacts F to thereby es tablish electrical connection of the circuit in which such a connector is installed. The male contacts 5i? and 5! are of known construction, that is split, to act with spring ac tion when moved into the female contacts F. The splitting of the female contacts F causes the split portions to give slightly when the parts are con nected, to thereby assure full electrical connec— tion between the contacts F and the contacts 50 and H of the plug. In order to aid in connection and disconnec tion of .the parts A and B, the outer surfaces of the nuts 5 may be knurled. 15 The construction of the various parts permits interchange of male and female connections in either housing. When the plug and receptacle parts A and B are connected, the outer surface thereof is con 20 tinuous, contains no projections to catch when the connector is dragged over a rough surface, and the frictional engagement between the con tact is su?icient to hold the parts together against any but abnormal endwise pull. 25 By reason of the fact that the circumferential dimensions of the tongues of the casing and the corresponding grooves of the mating insulating body member, are different, it is impossible to assemble the insulating body members in a cas 30 ing, in any but proper angular relationship. The invention has been described herein more or less precisely as to details, yet it is to be understood that the invention is not to be lim ited thereby, as changes may be made in the ar 35 rangement and proportion of parts, and equiva lents may be substituted, without departing from the spirit and scope of the invention. The invention is claimed as follows: 1. In an electric coupling of the class de 40 scribed; a shell; two separable insulating body members in said shell carrying a plurality of elec tric contacts; one or the inner of said body members being axially and then rotatably assem— bled in the shell; said shell and member having 45 cooperating tongue and groove means for guid ing the member axially and preventing rotative movement of said member until seated in said shell; said shell having an internal seat for said member; said shell and member having cooper ating means for limiting rotative movement of said member when seated; the other or outer of said members being axially assembled in said shell; said shell and said outer member having cooperating tongue and groove means for guid ing it and preventing relative rotation between it and said shell; said inner member having threaded bushings for receiving securing bolts; securing bolts in the outer of said members; said bushings and bolts being aligned when said inner 60 member is rotated to its limit in one direction; said shell having means constituting a shoulder engageable by said inner member when rotated to its limit in said one direction to prevent axial movement of the inner member away from 65 its seat, the construction being such that when said members are connected together by said bolts axial displacement of the connected mem bers is prevented by engagement of the inner member with said shoulder and rotative move 70 ment of the connected members is prevented by the tongue and groove guide means of said shell and said outer body member. ‘ ‘2. A separable electric connector part com 5 prising a shell open at one end, an insulating body within said shell carrying a plurality of electrical contacts, said body consisting of two separable members arranged in tandem in said shell and applicable to and removable from said shell through said open end, said shell having an an~ nular internal seat spaced inwardly from said open end, the inner of said members being as sembled in said shell against said seat and ro tated a limited amount, said shell and member having cooperating means to limit rotative move ment of said member, said inner member having threaded bushings for receiving securing bolts, the outer of said members being assembled by axial movement of said member into said shell and against said inner member, said outer mem ber carrying securing bolts for engagement with said bushings when said inner member is seated and rotated to its limit in said direction, said outer member and shell having cooperating= tongue and groove means for preventing relative rotative movement of said member and shell, the inner ends of said tongues stopping short of said seat to provide stop means for said inner member when seated and rotated to prevent axial move ment of said inner member, the construction be— ing such that when said two members are con nected by said bolts axial displacement is pre— vented by engagement of said inner member against the inner ends of said tongues and rota tive movement of the two connected members in the shell is prevented by the tongue and groove engagement of said outer member and said shell. 3. A separable electric connector part com prising a shell open at one end, an insulating , body within said shell carrying a plurality of elec trical contacts, said body consisting of two sepa rable members arranged in tandem in said shell and which members may be applied to and re moved from said shell through said open end, said 40 shell having an annular internal seat spaced in wardly from said open end, the inner of said members being assembled in said shell against said seat and rotated a limited amount, said shell and member having cooperating means to limit 45 rotative movement of said member, said inner member having threaded bushings for receiving securing bolts, the outer of said members being assembled by axial movement of said member into said shell and against said inner member, said 50 outer member carrying securing bolts for en gagement with said bushings when said inner member is seated and rotated to its limit in said direction, said outer member and shell having co operating tongue and groove means for prevent ing relative rotative. movement of said member and said shell, the inner ends of said tongues stopping short of said seat to provide stop means for said inner member when. seated and rotated to prevent axial movement of said inner member, and said outer member having stop means en gageable with the outer ends of said tongues to limit inward movement of said outer member, the construction being such that when said two mem bers are connected by said bolts axial displace 65 ment is prevented by engagement of said con nected members against the ends of said tongues and rotative movement of the two connected members in the shell is prevented by the tongue and groove engagement of said outer member and 70 said shell. THOMAS E. MCDOWELL.