US3314276A

US3314276A - Bellows forming machine

Info

Publication number: US3314276A
Application number: US358042A
Authority: US
Inventors: John F Peyton; Wassner Paul
Original assignee: Federal Mogul Bower Bearings Inc
Current assignee: INDIAN BAR COMPANY A CORP OF DEL
Priority date: 1964-04-07
Filing date: 1964-04-07
Publication date: 1967-04-18
Anticipated expiration: 1984-04-18

Description

April 18, 1967 J P Y O ET AL 3,314,276

BELLOWS FORMING MACHINE Filed April '7, 1964 5 Sheets-Sheet 1 iNVENi'ORS BY A401. Mass/wee fie, M Z

April 18, 1967 J PEYTON ET AL BELLOWS FORMING MACHINE 3 Sheets-Sheet 2 Filed April '7, 1964 INVENTORS g c/ZAWF. as 701v PAUL Mam/2 MW a/muzl April 18, 1967 J PEYTON ET AL 3,314,276

BELLOWS FORMING MACHINE Filed April 7, 1964 5 Sheets-Sheet 5 l v e 5 290,2 9. .140

15a 25a; L 150 A sa INVENTOR5 c/omvFPe /ro/v BY Ava; I ZFISSNEE W WM agm M A rme/vzys United States Patent 3,314,276 BELLOWS FQRMING MACHINE John F. Peyton, Long Beach, and Paul Wassner, Anaheim, Calif., assignors to Federal-Mogul-Bower Bearings, Inc., Detroit, Mich, a corporation of Michigan Filed Apr. 7, 1964, Ser. No. 358,042 14 Claims. (Cl. 72-370) The present invention relates generally to a method and apparatus for forming annular corrugations or convolutions in the walls of tubular bodies, and more particularly, to an improved method of making so'called metal bellows of the kind now extensively used in connection with thermostats and pressure-operated devices, valves, flexible, corrugated tubular conduits, fittings and the like articles.

This invention finds its most important application in connection with the manufacture of relatively large diametered, flexible, metal conduits, connections and the like piping devices for carrying various fluids.

Heretofore, in the manufacture of such metal bellows, or bellows type pipes, fittings, and the like'devices, various means have been employed for forming the circumferential annular folds or convolutions in the walls of a tubular work piece, such means including the employment of high hydraulic pressures internally of the tubular work piece -to stretch a portion of the tubular walls into conformity with a suitably formed annular die, the employment of one or more annular-shaped ram bodies for drawing the tubular stock into suitably-shaped die bodies, or the use of various kinds of roller presses for rolling the convolutions, usually in a plurality of stages. In all of such mechanical or hydraulic systems heretofore employed, the nature of the forming processes usually require a portion of the metal of the tubular work piece to be drawn or stretched over the edges of the forming tools, thereby subjecting the metal, not only to sharp bending and stretching action resulting in work hardening of the material, but also resulting in surface marring which is injurious not only to the appearance but to the strength and fatigue life of the finished article. The machines heretofore employed in the process of manufacture of such metal bellows articles and devices have also often 'been excessively massive, extremely expensive, and lacking in durability.

It is accordingly an object of this invention to provide an improved method of and apparatus for manufacturing flexible metal bellows and the like flexible tubular articles.

It is still another object of this invention to provide a flexible metal bellows manufacturing machine which is capable of manufacturing metallic bellows of improved quality.

It is a further object of this invention to furnish a metal bellows manufacturing machine capable of producing such 'bellows free from detrimental surface abrasions and scratches.

It is a further object of this invention to furnish an improved method and apparatus for forming metal bellows of improved uniformity and dimensional precision than heretofore usually possible.

It is a still further object of this invention to provide a machine for forming metal walled flexible bellows articles which are relatively free from inconsistencies and variations in hardness and elasticity and having relatively improved operating and durability characteristics.

It is a still further, important object of this invention to provide a method and apparatus for formation of metal bellows from low ductility metals which heretofore have been considered difficult, if not impracticable for such use, such as for example, stainless steel, certain high hardness aluminum alloys, titanium, and the like.

3,314,276 Patented Apr. 18, 1957 ice These and other objects and advantages, and features of the novelty will be evident hereinafter.

'In the drawings which show a presently preferred embodiment of the invention and in which like reference characters designate the same or similar parts throughout the several views:

FIGURE 1 is a view, partly in elevation and partly in vertical section, of the general assembly of the bellows forming machine of the invention.

FIGURE 2 is a horizontal, sectional view taken on line 2-2 of FIGURE 1.

FIGURE 3 is a fragmentary, side elevational view of a portion of the apparatus of FIGURE 2 as viewed from line 3-3, with portions of the apparatus remover for clarity of viewing.

FIGURE 4 is an enlarged, fragmentary, cross-sectional view taken on line 44- of FIGURES 1 and 2.

FIGURE 5 is an enlarged, fragmentary, vertical sectional view of that portion of the apparatus withinbroken lined circle A of FIGURE 1, illustrating the initial relative positions of the forming tool elements and the work piece, in readiness for commencement of a bellows c nvolution forming cycle of operation.

FIGURE 6 is a view of the same forming tool elements shown in FIGURES 1 and 5, illustrating their relative positions at an initial stage in the bellows convolution forming cycle of operation.

FIGURE 7 is a view of the same forming tool elements shown in FIGURES l and 5, but showing the relative positions thereof at a second stage in the progress of the bellows convolution forming cycle.

FIGURE 8 is a view of the same forming tool elements shown in FIGURES l and 5, but showing the relative positions thereof at a third stage in the progress of the bellows convolution forming cycle.

FIGURE 9 is a view of the same forming tool elements shown in FIGURES 1 and 5, but showing the relative positions thereof at a fourth stage in the progress of the bellows convolution forming cycle.

FIGURE 10 is a view of the same forming tool elements shown in FIGURES 1 and 5, but showing the relative positions thereof at a fifth stage in the progress of the bellows convolution forming cycle with the bellows convolution in completed form and with the work piece in readiness for vertical movement to a new position for formation of another bellows convolution.

FIGURE 11 is a view of the same forming tool element shown in FIGURES 1 and 5, but showing the positions thereof at a sixth and final stage of the bellows convolution forming cycle of operation, showing the bellows convolution in completed form and with the work piece moved to a new position corresponding to that shown in FIGURES 1 and 5, in readiness for initiation of the repetition of the forming cycle for another bellows convolution.

Referring first primarily to FIGURES 1 and 2, the machine assembly has a principal supporting structure or framework comprising a stationary, rectangular top platform 10 having a circular central opening 12 therein, a stationary rectangular lower base platform 14, also having a circular central opening 16 therein coaxial with opening 12, and four vertical, cylindrical supporting

column members

18, 20, 22 and 24 which support the top platform 19 and the lower base platform 14, in vertically elevated and fixed spaced-apart relation. The four column members are attached to the platforms 10 and 14 by suitable attachment means located adjacent the four corners thereof. The lower ends of the supporting

column members

18, 2Q, 22 and 24 extend below the corners of the lower base platform 14 a suitable elevational distance as shown at 26 and 28, and are provided at their lower ends with suitable base flanges as shown at 30 and 32 for support of the weight of the apparatus assembly on a suitable surface 34.

The top platform 10 serves operatively to support a split die mechanism shown generally at 139, as hereinafter more fully described.

Supported parallel to and adjacently beneath the top platform 10 is a generally rectangular, vertically movable, intermediate platform 36 having a central opening 38, coaxial with

openings

12 and 16, and provided adjacent its corners with

guide openings

42, 44, 46 and 48, through which the beforementioned supporting

column members

18, 29, 22 and 24 respectively guidingly extend. In operation, the intermediate platform 36, hereinafter referred to as the follower die supporting platform serves to vertically movably support an annular follower die member 128 as is hereinafter more fully described. The follower die supporting platform 36 is supported for limited vertical movement relative to the top platform 10 by means of four

hydraulic actuators

58, 52, 54, and 56, each of which comprises a cylinder 58 containing in its bore a piston 60 and from which extends a plunger 62, as best shown in FIGURE 1.

The lower ends of each of the cylinders 58 are fixedly supported upon brackets as shown at 64 which are attached to the

column members

18, 20, 22 and 24, and the plungers 62 are attached at their upper ends to corner portions of the follower die supporting platform 36 adjacent the

beforementione guide openings

42, 44, 46 and 48 therein.

The cylinders 58 are provided at opposite ends thereof with ports which enter the opposite ends of the cylinder bores on opposite sides of pistons 62, and to which hydraulic pressure connections are made, as shown at 66 and 68, for simultaneously raising and lowering the plungers 62 and the follower die supporting platform 36 carried thereby, as will be described hereinafter in connection with the operation of the apparatus.

Supported for vertical movement between the follower die supporting platform 36 and the base platform 14 is a generally rectangular-shaped work elevator and indexing table 70 having a central circular opening 72 therein coaxial with the

beforementioned openings

12, 16 and 38, The work elevator and indexing table 70 is supported for controlled vertical movement by four vertical, externally threaded,

elevator spindles

74, 76, 78, and 80 which pass through and make threaded engagement with threaded nut bearings attached to the elevator table 70 adjacent the corners thereof as shown at 82 and 84. The

elevator spindles

74, 76, 78 and 80 are rotatably supported adjacent their lower ends upon the base platform 14 by means of thrust bearings, two of which are in view at 86 and 88 in FIGURE 1. The lower ends of each of the

elevator spindles

74, 76, 78 and 80 are provided with integral extension shafts which pass through the thrust bearings and extend below the base platform as shown at 90 and 92 in FIGURE 1.

Fixed on each of the extension shafts of the

elevator spindles

74, 76, 78 and 80 are

chain sprockets

94, 96, 98 and 100 respectively, all rotatably linked together for simultaneous rotation by means of an encompassing, continuous link chain 182. One of the extension shafts, for example, that shown at 90 in FIGURE 1, carries an additional chain sprocket 104 which is drivingly connected by means of link chain 106 to a sprocket 108 carried on :he drive shaft of a motor 110 which is preferably of 1 positive displacement hydraulic type. In the operation 3f the apparatus, the chain sprocket 104 is driven by notor 110, thereby simultaneously driving the

chain iprockets

94, 96, 98 and 100 and the corresponding

elevaor spindles

74, 76, 78 and 8G. The motor 110 is suitibly mounted upon a bracket 112 which is bolted to the inder surface of the base plate 14.

The upper ends of the elevator spindles 74, 76, 78 and K extend rotatably and relatively axially slidable through :learance openings, as shown at 114 and 116, extending through the follower die supporting platform 36, with the upper ends of the spindles rotatably journaled in bearings, as shown at 118 and 120, fixed to a portion of the lower surfaces of the top platform 10. The work elevator table is provided with a plurality of vertical, upwardly extending indexing pins 122. The indexing pins 122 may have any suitable arrangement in table 70 to accommodate the size and shape of the work piece upon which forming operations are to be performed, but in the present apparatus, they are preferably arranged circumferentially spaced-apart, on a circle, coaxial with the beforementioned opening 72 and having a diameter slightly less than the internal diameter of the tubular work piece. The work piece 124 is thereby positioned vertically in the apparatus with its lower end centered and supported on the work elevator table 70, surrounding the beforementioned pins 122.

Seated in a depressed, upwardly facing annular groove 126, formed coaxially around the inner marginal portioning of the beforementioned central opening 38 in the follower die supporting platform 36, is an external, generally annular-shaped die member 128 hereinafter referred to as the follower die. The follower die 128 is formed with a central, upstanding, annular collar portion 130 having a coaxial bore 131 which, in the present instance, has an internal diameter which makes a slidable fit with very slight clearance around the exterior surface of the tubular work piece 124.

Attached to the underside of the top platform 10 and comprising a portion of the beforementioned split die mechanism 139 is a pair of elongated, transversely extending, parallel slide guides 134 and 136, and slidably supported in said guides against the under side of the top platform 10 are a pair of oppositely positioned split

die carrier plates

138 and 140. The inner, adjacently confronting edge portions of the split

die carrier plates

138 and 140 are semi-circular in form, as shown at 142 and 144, whereby, when they are slidingly closed together in the guides 134 and 136 in end-to-end abutment with one another, they form a closed circular opening therebetween which, in the present instance, coaxially encircles the tubular work piece 124. The split

die carrier plates

138 and 140 are formed around their inner semi-circular edges with radially inwardly extending, round-edged, coaxial die elements 146 and 147 respectively of reduced thickness which, when the

die carrier plates

138 and 140 are in closed position, form in effect a relatively thin split annular die ring. The thickness of the thus formed split die ring and the radius of curvature of the inner edge thereof is made to correspond approximately to the desired spacing between and the radius of curvature of the inner edges of the convolution to be formed in the tubular work piece.

Pin connected to the outer end edges of the split

die carrier plates

138 and 140, by means of pin fittings, as shown at 148 and 150 respectively, are a pair of laterally extending, split

die actuator rods

152 and 154. The outer end portions of the split

die actuator rods

152 and 154 are externally threaded as shown at 156 and 158, and are operatively coupled for reciprocable motion, to split die actuator jacks shown generally at 157 and 159. The split

die actuator jacks

157 and 159 are provided with internally threaded

drive nuts

160 and 162 which make threaded connection with the externally threaded portions of the

actuator rods

152 and 154 which are, in turn, drivingly coupled through suitable

worm gear drives

164 and 166 to

hydraulic motors

168 and 170. The housings for the internally threaded

drive nuts

160 and 162, together with their worm

gear drive elements

164 and 166, and the

hydraulic motors

168 and 170 are supported outboard of the top platform 10 and in alignment with the actuated

rods

152 and 154, by means of

brackets

172 and 174 which are attached at their inner ends to the upper marginal portions of the top platform 10 by suitable means such as bolting or welding.

Fixed to and supported upon the central portion of the base platform 14 coaxial with the opening 16 therein, and coaxial with the

openings

12 and 38 in the top plat form 19 and follower die platform 36, is a vertically extending guide tube 176. Axially slidable within the guide tube 176 is a tubular supporting column 178 which carries upon its upper end an internal expansion die mechanism assembly shown generally at 180. The lower end of the tubular supporting column 178 is coaxially fixed to a flanged fixture 182 which is in turn fixed to the central portion of a rectangular shaped, expansion die assembly supporting plate 184.

The supporting plate 184 is vertically, resiliently and adjustably supported adjacent its four corners upon four adjustable, vertically resilient supporting means 185 each comprising an external helical spring 186 which contains within it a hollow, resilient, expansible air cushion 188. The lower ends of the helical springs 186 and air cushions 188 are supported upon a rectangular elevator frame 190 which is in turn vertically, adjustably supported at its four corners upon four jack-screws 192, which extend upwardly from four jack-screw mechanisms, two of which are in view and generally indicated at 196 in FIGURE 1. All four of the jack-screw mechanisms 196 are adapted to be simultaneously driven at the same rate through a system of interconnected shafts and gear boxes, a portion of which are shown at 200, 202, and 204, by means of a motor 206 which is preferably of a positive displacement hydraulic type. The jack-screw mechanisms 196 are supported by means of base flanges 208 upon the beforementioned surface 34.

A limit switch 209 attached to a fixed support 211 and positioned adjacent the rectangular elevator frame 190 is provided as a part of the electrical control circuit, not shown, for the motor 206. The switch include a toggle arm 213 which is coupled to a switch mechanism within the housing of the switch such that the electrical circuit to the motor is opened, thereby de-energizing the motor at upper or lower pivotal positions of the toggle arm. The toggle arm is positioned to be actuated by upper and

lower stops

215 and 217 adjustably positioned on a rod 219 which is attached to the adjacent end of the frame 190. Predetermined upper and lower limit of travel of the frame 199 is thus determined as required for the bellows convolution forming cycles of the forming dyes.

Supported by and extending axially downwardly from the underneath side of the suporting plate 184 is a hydraulic expansion die actuating cylinder 212 having inlet and

outlet port connections

214 and 216 entering the upper and lower ends respectively of the bore thereof. Axially, slidably contained within the bore of the actuating cylinder 212 is an expansion die actuating piston 218 to which is connected a piston rod 220 and which extends coaxially upwardly through the upper end of the cylinder through a suitable piston rod seal 222. The upper end of the piston rod 220 is threadedly connected at 224 with the lower end of an expansion die actuating push-pull rod 226 which extends upwardly, coaxially within the supporting column 178 and makes fixed connection adjacent its upper end with a downwardly tapered, frustoconical expansion actuator wedge 230, which comprises a portion of the beforementioned internal expansion die mechanism assembly shown generally at 180.

Also included within the internal expansion die mechanism assembly 180 is an expansion die supporting head 232 which includes a downwardly extending cylindrical seat portion 234 which makes telescopic supporting engagement at 236 within the upper end of the beforementioned supporting column 17 8 and which carrie an upper, generally annular, expansion die-carrier supporting flange 238. Radially, slidably supported upon the upper surface of the supporting flange 238 upon radial dovetail guides, as best shown at 240 in FIGURE 4, are a plurality of circumferentially adjacently positioned, die carrier sectors 242 to 264 as shown in FIGURE 2, and two of which are also shown at 250 and 264 in FIGURE 1. Each of the expansion die carrier sectors carries fixed adjacent its radially outer edge, an expansion die element as shown at 266 to 288 in FIGURE 2 and two of which are in view in elevation at 278 and 288 in FIGURE 1. Each of the expansion die elements 266-288 carries an integrally formed, outwardy extending, relatively thin, roundedged, arcuate die segment, :as shown at 290 and 292 in FIGURE 1. The thickness of each of the die segments and the radius of curvature of the outer edges thereof are made to correspond approximately to the desired spacing between and the radius of curvature of the edges of the convolutions to be formed thereby in the tubular work piece.

An annular shaped, helically wound, garter spring 294 encircles the upstanding portions of the expansion die carrier sectors 242-264 and serves to bias or urge the expansion die carrier sectors and the expansion die elements carried thereby toward their most radially inwardly retracted positions relative to the expansion die carrier supporting flange 238 and the dovetail guides 240 thereon. The radially inner sides of each of the expansion die carrier sectors 242-264 is formed with a downwardly convergingly, circumferentially curved surface which closely matches the downward tapering frustoconical exterior surface of the actuating wedge 230 upon which they slidingly bear, and these surfaces are retained in sliding engagement with one another by means of the beforementioned encircling garter spring 294. The lower end portion of the push-pull rod 226 is threaded as shown at 298 and carries threaded thereon an annular stop nut 300. In operation, the annular stop nut 300 adjustably limits the downward movement of the push-pull rod 226 by abutment thereof with the upper end of sleeve 302 which forms an upper extension of the beforementioned flanged supporting fixture 182.

Referring to the heretofore described apparatus, its operation is as follows:

The tubular work piece 124 upon which the bellows forming operation is to be formed is first inserted vertically down through the opening 12 in the top platform 10 and opening 131 in the collar portion of the follower die 128 and lowered to the position shown in FIGURE 1 at which its lower end rests upon the work elevator and indexing table 70 at a centered location surrounding the indexing guide pins 122 therein. The tubular work piece 124, the external split die elements 146 and 147, the external follower die 128 and the internal expansion die segments 290, 292, are then initially in the relative positions best shown in FIGURE 5.

Next, fluid under pressure is introduced through port 214 into the upper end of the expansion die actuating cylinder 212 above the piston 218, thereby applying a downward force to the piston 218 and an equal and opposite upward force to the cylinder 212. The upward force from the cylinder 212 is transmitted upwardly through the supporting column 178 to the expansion die carried supporting flange 238, and the downward force from the piston 218 is transmitted through the push-pull rod 226 to the expansion die actuator wedge 230 which causes the expansion die carrier sectors 242-264 the expansion die elements 266288 carried thereby and the arcuate die segments 290, 292 to move radially outwardly, initially to the position illustrated in FIGURE 6 at which the rounded outer edge of the expansion die segments 290, 292 make contact with the inner surface of the tubular work piece 124 at a point intermediate the external split dies 146 and 147, and the top of the follower die collar 130. A slight circumferential bulge is thus initiated at this point in the tubular work piece 124 as illustrated at 304 in FIGURE 6. No axial movement is imparted to the expansion die segments during the initial expansion movement.

Immediately following the commencement of the formation of the bulge 304 in the tubular work piece --124,

simultaneous upward movement of the follower die 128 and the expansion dies 290, 292 is initiated. Such upward movement of the follower die is effected by introduction of fluid under pressure through connections 68 into the

hydraulic actuators

50, 52, 54, and 56 at a controlled rate from a pressure source, not shown. The upward movement of the expansion dies are effected by energizing and controlling the speed of motor 206 which drives the screw jacks 196 to impart upward movement to the frame 190 which in turn imparts upward motion through the resilient supporting means 185 including springs 186 and air cushions 188, to the elevator platform 184 and thence through the supporting column 178 to the expansion die assembly 180. The outward and upward movements of the expansion die segments 290, 232 and the upward movement of the follower die 128 are simultaneously continued until they reach the relative positions shown in FIGURE 7 at which the convolution is thereby fully formed in the work piece 124 as shown at 306. At this point, sufficient clamping force is applied upon the upper and lower surfaces of the convolution 306 between the upper surface of the follower die collar 130 and the lower surface of the split dies 146, 147, to insure complete formation of the convolution 306 in conformity with the shape of the expansion die segments 290, 292 as shown in FIGURE 7.

Next, the follower die 128 is lowered sufliciently to remove the clamping pressure from the lower surface of the newly formed convolution 306 as illustrated in FIG- URE 8, such lowering of the follower die 128 being accomplished by introducing fluid under pressure through connections 66 and exhausting fluid from connections 68 of the hydraulic actuators 5056 at a controlled rate.

Next, following the initiation of the downward movement of the follower die 128, the split die

plates

138 and 140 are opened by actuation of the split die

actuator jacks

157 and 159, thereby withdrawing the split dies 146 and 147 from encirclement of the work piece 124, to the position illustrated in FIGURE 9, leaving the work piece 124 then suspended by the convolution 306 upon the internal expansion die segments 290, 292 as shown in FIGURE 9.

Next, the internal expansion die segments 290, 292 are retracted by introduction of fluid pressure through port 216 and exhausting fluid from port 214 of the expansion die actuating cylinder 212, thereby applying upward force to piston 218 which force is transferred through the push-pull rod 226 to the actuator wedge 230 thereby moving the actuator Wedge 230 upwardly, permitting the garter spring 294 to retract the expansion die carrier sectors 242-264 radially inwardly on the dovetail guides 240 on the expansion die carrier supporting flange 238. This retraction of the expansion dies 290, 292 permits Lhe work piece 124 to drop to a position in which it is iupporting upon the upper end of the follower die collar [30 by the previously formed convolution 306 as shown 11 FIGURE 10.

Next, or preferably a short time prior to the beforelescribed retraction of the expansion die segments 290, I92 the motor 110 is actuated, which through the inter- :onnecting chain and sprocket drive, simultaneously otates the elevator spindles 74, 76, 78 and 80 in a direcion which, through the action of the threaded nut bearngs 82-84 thereon raises the elevator table 70 upwardly nto supporting contact with the bottom end of the tubular vork piece 124. Upward movement of the table 70 is hen continued until the work piece 124 is elevated a listance sufficient to permit the split dies 146 and 147 to re closed under the lower surface of the previously formed 'ellows convolution 306, as shown in broken lines in FIG- JRE 11. Meanwhile, the downward movement of the ollower die 128 is continued until it reaches its lowermost osition, which is the position it initially occupied as hown in FIGURES 1 and 5. At this point, the apparatus icluding the expansion dies 290, 292, split dies 146 and .47, and follower die 128 are again in position in readiation cycle as beforedescribed.

ness for the commencement of the formation of another, succeeding bellows convolution by repetition of the form- These formation cycles are sequentially repeated a number of times equal to the number of axially adjacent bellows convolutions desired to be formed in the tubular work piece.

An important feature of this invention resides in the prevention of any substantial rubbing or sliding action at the areas of forceful contact between the die members and the work piece at any time during the convolution formation cycle or thereafter. This is accomplished by the hereinbefore described controlled relative movements of the dies, such that from the beginning of the formation of the bellows convolution as shown at 304 in FIGURE 6 to the completion thereof as shown in FIGURE 7, both the follower die 128 and the expansion die segments 290, 292 move simultaneously upwardly relative to the split die elements 146, 147 the expansion die segments 290, 292 moving upwardly as the convolution fold is formed at a rate which is approximately one-half the rate of upward movement of the follower die 128. Thus, the point of forceful contact of the rounded ends of the expansion die segments 290, 292 with the inside surface of the tubular work piece 124 remains substantially fixed in position thereon, and, likewise, the restraining contact of the exterior surface of the work piece 124 with the bore 131 of the follower die 128 during the convolution forming cycle also remains substantially fixed relative to one another. Thus, substantially all rubbing movements between the contacting surfaces of the dies and the work piece are eliminated.

The regulation of the relative vertical movements of the expansion die segments 290, 292, and follower die 128 to correspond precisely to that which would result in their having no sliding movement relative to the surface of the work piece 124 as the convolution is formed, would be difficult, if not impossible to accomplish, because the axial movement of the work piece material within and adjacent the bellows convolution being formed is a complex and possibly unpredictable function of the form, size and shape of the convolution being formed and the thickness and physical characteristics of the material involved. Thus, the required relationship between the axial movements of the expansion die segments 290, 292 and follower die 128 is so complex as to be impracticable of complete positive control.

To overcome the foregoing difliculty in controlling the relative axial movements of the dies, the expansion assembly is elevated as hereinbefore described by the jacks 196, and the follower die 128 is simultaneously elevated by pistons 60 of the four

hydraulic actuators

50, 52, 54 and 56 during the convolution formation cycle, at rates which only approximate that necessary to accomplish the beforedescribed relative movements. Any discrepancy between the thus controlled rates of axial movement between the expansion die segments 290, 292 and follower die 128 is accommodated automatically by limited variation in axial movement of the supporting column 178 and the expansion die mechanism 180 carried thereby, permitted by the floating effect of the resilient supporting means 185, which as beforedescribed, includes the springs 186 and air cushions 188 positioned between the supporting plate 184 and the rectangular elevator frame 190 which is in turn supported on the jack screws 192 of the jacks 196. Thus, once the bellows convolution bulge is commenced as shown at 304 in FIGURE 6, there is sufiicient resiliency in the supporting means to permit the expansion die 290 to remain at a fixed point of contact upon the inner surface of the work piece 124 as the convolution fold progresses.

The upper and lower limits of travel of the elevator frame is controlled as required by the limit switch 209, by adjustment of the positions of

stops

215 and 217.

The resiliency of the resilient supporting means 185 between the rectangular frame 190 and the supporting 9 plate 184, and also the spacing therebetween may be varied to some extent by variation of fluid pressure, preferably air pressure, introduced into the air cushions 188 through the inlets 187, 189. In this manner, changes in size of tooling or other weight influencing factors can be accommodated.

The hereinbefore described apparatus and the method of operation thereof has proved to be advantageous in making it possible to go to greater extremes than heretofore possible with respect to the ratios of radial depth to axial spacing and tightness of the bellows convolutions formed, also to hold closer and consistently repeatable dimensional tolerances as well as to result in generally superior products in respect to freedom from detrimental mam'ng, bumishing, scratching and injurious cold working and thinning of the work materials. These advantages have been found to extend to the forming of bellows of a wide range of sizes from medium to large diameter in the order of 50 inches.

It is to be understood that the foregoing is illustrative only and that the invention is not limited thereby, but may include various modifications and changes made by those skilled in the art within the scope of the invention as defined in the appended claims.

What is claimed is:

1. In a machine for forming bellows from tubular stock, apparatus comprising:

supporting and positioning means for such tubular stock;

a first die means positioned for restraining encirclement of a first circumferential portion of the external surface of such tubular stock;

a second die means positioned for restraining encirclement of a second circumferential portion of the external surfaces of such tubular stock, said first die means and second die means being spaced-apart relative to one another axially of such tubular stock;

means mounting said first and second die means for limited movement relative to one another, axially of such tubular stock;

a third die means having a rigid, external, peripheral portion positioned for encirclement thereof by such tubular stock at a location axially intermediate said first and second die means;

means for moving said peripheral portion of said third die means generally radially outwardly into forceful engagement with the internal encircling surface of such tubular stock, to form an outward circumferential bulge in such tubular stock extending between said first and second die means;

and means for simultaneously continuing such movement of said peripheral portion of said third die means generally radially outwardly, and such movement of said first and second die means relatively toward one another axially of such tubular stock, until completion thereby of an outwardly projecting, circumferentially extending convolution in the wall of said tubular stock intermediate said first, second and third die means.

2. In a machine for forming metal bellows from tubular metal stock, apparatus comprising:

means for positioning such tubular stock in said machine;

means mounting said third die means for limited movement relative to said first and second die means axially of such tubular stock;

and means for simultaneously continuing such movement of said peripheral portion of said third die means generally radially outwardly, and such movement of said first, second and third die means relatively toward each other axially of such tubular stock, until completion thereby of an outwardly projecting, circumferentially extending convolution in the wall of said tubular stock intermediate said first, second and third die means.

3. In a machine for forming metal bellows from tubular metal stock, apparatus comprising:

supporting means for such tubular stock;

means mounting said third die means for limited movement of said peripheral portion thereof relative to said first and second die means axially of such tubular stock;

means for movement of said peripheral portion of said third die means generally radially outwardly into forceful engagement with the internal encircling surface of such tubular stock, to form an outward circumferential bulge in such tubular stock extending between said first and second die means;

and means for simultaneously continuing such movement of peripheral portion of said third die means generally radially outwardly, and such movement of said first and second die means relatively toward one another axially of such tubular stock and maintaining said peripheral portion of said third die means at said location intermediate said first and second die means, until an outwardly projecting, circumferentially extending convolution is completed in the wall of said tubular stock intermediate said first, second and third die means without substantial sliding movement of said first, second, and third die means axially upon the surfaces of such tubular stock at the areas of contact therebetween.

4. In a machine for forming metal bellows from tubular metal stock, apparatus comprising:

I 3 limited movement relative to one another, axially of such tubular stock;

a third die means having a rigid, external, peripheral portion positioned for encirclement thereof by such tubular stock at a location axially substantially midway between said first and second die means;

means mounting said third die means for limited movement of said peripheral portion relative to said first and second die means axially of such tubular stock;

means for movement of said portion of said third die means into forceful engagement with the internal encircling surface of such tubular stock, to form an outward circumferential bulge in such tubular stock extending between said first and second die means;

and means for simultaneously continuing such movement of said third die means, and for moving said first and second die means relatively toward one another axially of such tubular stock and maintaining said portion of said third die means at said location between said first and second die means until completion of an outwardly projecting, circumferentially extending convolution in the wall of said tubular stock intermediate said first and second die means and said portion of said third die means,

said movements being without substantial sliding movement of said first and second die means and said portions of said third die means axially upon the surface of such tubular stock at the areas of contact therebetween.

5. In a machine for forming metal bellows from tubular metal stock, apparatus comprising:

supporting means for positioning such tubular stock in said machine;

a third die means having a rigid, external, peripheral portion movable transversely between retracted and extended positions and positioned for encirclement thereof by such tubular stock at a location axially intermediate said first and second die means;

power means for moving said portion of said third die means between said retracted and extended positions relative to said internal encircling surface of such tubular stock extending between said first and second die means;

means for moving said first and second die means relatively toward one another axially of such tubular stock simultaneously with transverse movement of said portion of said third die means towards such extended position for forming an outwardly projecting, circumferentially extending convolution in the portion of the wall of such tubular stock located intermediate said first and second die means;

means included in said power means for retracting said portion of said third die means clear of such convolution following the formation thereof;

and means for moving said supporting means a predetermined distance axially of such tubular stock, following said retraction of said portion of said third die means, for positioning such tubular stock for formation of another convolution axially adjacent the first-mentioned convolution.

6. In a machine for forming metal bellows from tubular metal stock, apparatus comprising:

supporting means for positioning such tubular stock in said machine;

a first die means movable between transversely open and closed conditions and positioned for close encirclement of a first circumferential portion of the external surface of such tubular stock when closed;

a second die means positioned for close encirclement of a second circumferential portion of the external surfaces of such tubular stock, said first die means and second die means being spaced-apart relative to one another axially of such tubular stock;

a third die means having a rigid, external, peripheral portion movable between transversely retracted and extended positions and positioned for encirclement thereof by such tubular "stock at a location axially intermediate said first and second die means;

means for moving said first and second die means relatively toward one another axially of such tubular stock simultaneously with movement of said portion of said third die means toward said extended position for forming an outwardly projecting, circumferentially extending convolution in the wall of such tubular stock located intermediate said first and second die means;

means for moving said first die between said open and closed conditions to permit, when in opened condition, passage axially therethrough of a convolution formed in such tubular stock as aforesaid;

and means for moving said supporting means a predetermined distance axially of such tubular stock for moving such stock and a previously formed convolution therein through said first die means as aforesaid and for positioning such tubular stock for formation of another convolution axially adjacent the first-mentioned convolution.

7. In a machine for forming bellows from tubular stock, apparatus comprising:

supporting and positioning means for such tubular stock;

supporting means supporting said third die means including said peripheral portion thereof for limited movement relative to said first and second die means axially of such tubular stock, said supporting means including a resilient coupling between said third die means and at least one of said first and second die means permitting said third die means limited freedom for axial movement relative thereto;

and means for moving said peripheral portion of said third die means into forceful engagement with the internal encircling surface of such tubular stock, to form an outward circumferential bulge in such tubular stock extending between said first and second die means and said peripheral portion of said third die means.

8. In a machine for forming metal bellows from tubular metal stock, apparatus comprising:

supporting means for such tubular stock;

means supporting said third die means including said peripheral portion for limited movement relative to said first and second die means axially of such tubular stock, said means including axially resilient coupling means between said third die means and at least one of said first and second die means for permitting said third die means to remain at said location axially intermediate said first and second die means;

means for moving said peripheral portion of said third die means transversely into forceful engagement with the internal encircling surface of such tubular stock, to form an outward circumferential bulge in such tubular stock extending between said first and second die means;

and means for simultaneously continuing such movement of said portion of said third die means, and moving said first and second die means relatively toward one another axially of such tubular stock,

thereby permitting formation of an outwardly projecting, circumferentially extending convolution in the wall of said tubular stock intermediate said first and second die means and said peripheral portion of said third die means without substantial sliding movement of said first and second die means and said peripheral portion of said third die means axially on the surfaces of such tubular stock at the areas of contact therebetween.

9. In a machine for forming bellows from tubular stock,

apparatus comprising:

supporting and positioning means for such tubular stock;

a third die means having an external, peripheral portion positioned for encirclement thereof by such tubular stock at a location axially intermediate said first and second die means;

means for moving said peripheral portion of said third die means into forceful engagement with the internal encircling surface of such tubular stock, to form an outward circumferential bulge in such tubular stock extending between said first and second die means;

and means for imparting a predetermined movement of said third die means relatively toward one of said first and second die means axially of such tubular stock, while simultaneously continuing such expansion of said peripheral portion of third die means, said means for imparting said predetermined movement including resilient coupling means permitting movement of said third die means which departs limitedly axially from said predetermined movement,

thereby forming an outwardly projecting, circumferentially extending convolution in the wall of said tubular stock intermediate said first and second die means and said peripheral portion of said third die means without substantial sliding movement of said peripheral portion of said third die means axially relative to the surface of such tubular stock 'at the point of contact therebetween.

10. In a machine for forming bellows from tubular stock, apparatus comprising:

a supporting structure including an upper platform having an opening therein for encircling a tubular work piece positioned vertically therethrough;

a lower platform vertically, slidably supported in said structure, for supporting and elevating such tubular work piece;

an intermediate supporting means vertically slidably supported in said structure intermediate said upper platform and said lower platform;

a first external die means including die elements slidably supported on said upper platform for movement transversely between open and closed positions, said die means being adapted closely to encircle the exterior of such tubular work piece when closed and to clear the external diameter of convolutions formed in said tubular work piece when opened;

a second external die means carried on said intermediate supporting means and having an opening therein coaxial with said first-mentioned opening for closely encircling the exterior of such tubular work piece;

an interior expansion die means supported in said supporting structure in position to be encircled by such tubular work piece, and including a rigid, expansion die element expandable generally radially into forceful Contact with the interior surface of such tubular work piece, axially intermediate said first and second external die means;

vertically movable carrier means for supporting said expansion die means as aforesaid, said carrier means including power means carried thereby for applying such expanding movement to said expansion die element;

means supporting said vertically movable carrier means and said power means, including means for imparting controlled vertical movement thereto relative to said supporting structure, thereby to impart controlled vertical movement to said expansion die means relative to said first and second die means;

means for imparting controlled vertical movement to said intermediate supporting means relative to said supporting structure;

and means for imparting controlled vertical movement to said lower table relative to said supporting structure.

11. Apparatus according to claim 10 in which said means supporting said vertically movable carrier means includes resilient coupling means between said means supporting said vertically movable carrier means and said means for imparting controlled vertical movement thereto, permitting limited departure in vertical movement of said expansion die means from such controlled movement.

12. A method of forming bellows convolutions in a tubular work piece comprising:

applying circumferentially extending, radial restraint to the exterior surface of such tubular work piece at two, axially spaced-apart locations thereon;

expanding a circumferentially extending rigid forming body radially against the interior surface of said work piece axially intermediate said two spaced-apart locations, and thereby forming a circumferential, radially outwardly extending bulge in the wall of said work piece therebetween; and moving said forming body axially relative to said axially spaced-apart locations such as to maintain the areas of mutual contact of said forming body and applying circumferentially extending, radial restraint to said interior surface of said work piece substantially the exterior surface of said tubular work piece at free from axial sliding motion relative to one another two axially spaced-apart, exterior locations thereon; while continuing expanding of said forming body, applying a rigid forming body to the interior surface of and thereby increasing the radially outwardly eX- said work piece along an interior circumferentially tending depth of said bulge. extending contact area axially intermediate said 13. A method of forming bellows convolutions in a spaced-apart locations, with sufiicient force to form tubular work piece comprising: an initial annular, radially outwardly extending bulge applying circumferentially extending, radial restraint to in the wall of said work piece intermediate said the exterior surface of such tubular Work piece at spaced-apart exterior locations; two, axially spaced-apart locations thereon; and moving said two axially spaced-apart exterior locaexpanding a circumferentially extending rigid forming tions and said interior contact area of said body body radially against the interior surface of said relatively axially toward each other to reduce the work piece, axially intermediate said two spacedapart locations, and thereby forming a circumferential, radially outwardly extending bulge in the wall axial spacings therebetween while continuing application of said expanding force and the resulting continuing radially outwardly deepening of said bulge.

of said work piece therebetween;

and moving said forming body axially relative to said axially spaced-apart locations such as to maintain the areas of mutual contact between said forming References Cited by the Examiner UNITED STATES PATENTS body and said interior surface of said work piece and 2,306,018 1 4 Fentress 72-59 between the exterior surface of said work piece d 2,353,253 7/ 1944 Llvermont 72-399 said spaced-apart locations thereon substantially free 2,756,804 9 6 sChmdler et a1 72-59 from axial displacement relative to said interior and 2,773,538 959 De Mers 72 59 exterior surfaces while continuing the expansion of 2,960,142 11/1960 CIm ChOWSkI 72-62 Said forming body and the resultant increasing of the 3,130,771 4/1964 Peyton 7259 radially outwardly extending depth of said bulge, to form a completed bellows convolution. 14. A method of forming bellows convolutions in a tubular work piece comprising:

CHARLES W. LANHAM, Primary Examiner.

A. L. HAVIS, E. M. COMBS, Assistant Examiners.

Claims

1. IN A MACHINE FOR FORMING BELLOWS FROM TUBULAR STOCK, APPARATUS COMPRISING: SUPPORTING AND POSITIONING MEANS FOR SUCH TUBULAR STOCK; A FIRST DIE MEANS POSITIONED FOR RESTRAINING ENCIRCLEMENT OF A FIRST CIRCUMFERENTIAL PORTION OF THE EXTERNAL SURFACE OF SUCH TUBULAR STOCK; A SECOND DIE MEANS POSITIONED FOR RESTRAINING ENCIRCLEMENT OF A SECOND CIRCUMFERENTIAL PORTION OF THE EXTERNAL SURFACES OF SUCH TUBULAR STOCK, SAID FIRST DIE MEANS AND SECOND DIE MEANS BEING SPACED-APART RELATIVE TO ONE ANOTHER AXIALLY OF SUCH TUBULAR STOCK; MEANS MOUNTING SAID FIRST AND SECOND DIE MEANS FOR LIMITED MOVEMENT RELATIVE TO ONE ANOTHER, AXIALLY OF SUCH TUBULAR STOCK; A THIRD DIE MEANS HAVING A RIGID, EXTERNAL, PERIPHERAL PORTION POSITIONED FOR ENCIRCLEMENT THEREOF BY SUCH TUBULAR STOCK AT A LOCATION AXIALLY INTERMEDIATE SAID FIRST AND SECOND DIE MEANS; MEANS FOR MOVING SAID PERIPHERAL PORTION OF SAID THIRD DIE MEANS GENERALLY RADIALLY OUTWARDLY INTO FORCEFUL ENGAGEMENT WITH THE INTERNAL ENCIRCLING SURFACE OF SUCH TUBULAR STOCK, TO FORM AN OUTWARD CIRCUMFERENTIAL BULGE IN SUCH TUBULAR STOCK EXTENDING BETWEEN SAID FIRST AND SECOND DIE MEANS; AND MEANS FOR SIMULTANEOUSLY CONTINUING SUCH MOVEMENT OF SAID PERIPHERAL PORTION OF SAID THIRD DIE MEANS GENERALLY RADIALLY OUTWARDLY, AND SUCH MOVEMENT OF SAID FIRST AND SECOND DIE MEANS RELATIVELY TOWARD ONE ANOTHER AXIALLY OF SUCH TUBULAR STOCK, UNTIL COMPLETION THEREBY OF AN OUTWARDLY PROJECTING, CIRCUMFERENTIALLY EXTENDING CONVOLUTION IN THE WALL OF SAID TUBULAR STOCK INTERMEDIATE SAID FIRST, SECOND AND THIRD DIE MEANS.