US2963069A - Apparatus for forming heat exchange tubing - Google Patents

Description

Dec. 6, 1960 s. F. PASTERNAK 2,963,069

APPARATUS FOR FORMING HEAT EXCHANGE TUBING Filed July 23, 1958 5 Sheets-Sheet 1 FIG! BY phi" ATT'Y 5 Sheets-Sheet 2 INVENTR:

ATT'Y s. F. PASTERNAK APPARATUS FOR FORMING HEAT EXCHANGE TUBING Filed July 28, 1958 Dec. 6, 1960 STEPHEN F. PASTERNAK u :2 q V o: mum

n== w em 8 E. m 1% mm h H l me No Q? b h Dec. 6, 1960 s, PASTERNAK 2,963,069

APPARATUS FOR FORMING HEAT EXCHANGE TUBING Filed July 28, 1958 5 Sheets-Sheet 3 INVENTOR: STEPHEN F. PASTERNAK ATT'Y Dec. 6, 1960 PASTERNAK APPARATUS FOR FORMING HEAT EXCHANGE TUBING Filed July 28, 1958 5 Sheets-Sheet 4 I INVENTORE STEPHEN F PASTERNAK BY ATT'Y APPARATUS FOR FORMING'HEAT EXCHANGE TUBING Stephen F. Pasternak, 8654 Lyndale Ave., River Grove, 11].

Filed July 28, 1958, Ser. No. 751,551

2 Claims. (Cl. 153-80) The present inventionrelatesto heat exchange tubing and has particular reference to apparatus for producing a series of outwardlyextending small blunt generally conical protuberancesin the cylindrical wall of a length of tube stock, the protuberances being arranged in spaced relationship according to a predetermined pattern.- A length of cylindrical tube stock, when operated upon by the apparatus of the present invention, may be telescopically-received withina second length of tube stock and the, protuberances of the inner, length will serve to maintainthe two lengths oftube stock in spaced concentric relation'shipso-that aifluid passing through the .inner length will exist inzheat-exchange relationship relative to a-fluid passing. through ,theannulus created between the two' concentric-lengths of tube; stock.

Briefly, the invention contemplates the'prov-ision of a fully automatic machine by means of whichv a length of tube stockis intermittently fedalong a fixed arbor, rotated during the feeding operations, and'deforming; dies actuated at the termination of each feeding'operation so that the tube stock is'progressively dimpled from one end thereof-to-the'other. Briefly, the machine, in additionto the fixed arbor and'forrning dies, includes a set of backing dies which are circumferentially spaced around the .tube stock at the .formingstation and which are movable radially ofthe stock between retracted positions wherein they are remote from the surface of the tube, and advanced positionswherein-th ey are in close proximity to, or.in. engagement with, the surface ofthe tube so that they may cooperate with theforming dies when the latter move. to their advanced positions inorder to produce sharply. defined protuberances on the tube. stock. The machineiurtherv includes novel tube advancing means in the. form of a pair of clamping jaws which operate in the medial regions. ofthe. arbor toperiodically close upon the tube and engage the .same between them and, after a .firrn- .griphas,.been'obtained upon the tube, to move bodily forwardly alongthe. arbor so as to slide the tube :alongthe latter and bringtresh unformed surfaces into registerwith the forming dies .at the forming station. The clampingjaws are. movablebodily with a swinging carriage andlthe latter has associated therewithcam means whereby, as the carriage is advancedto carry the closed jaws along the arbor, the carriage will be swung throughout a slight angle to cause the. jawsrto rotate the tube through a corresponding angle so that the succeeding protuberances formed at the forming station will be slightly offset circumferentially to produce the aforementioned helical rows of protuberances. The various movable machine instrumentalities including the forming dies, the backing dies therefor, and the clampingjaws are sequentially operable in timed relation in repetitious cycles of operation with each moving instrumentality serving, at the completion of its. effective movement, to. initiate commencement ofthe motion ofrthe next instrumentality in the sequence, and/with the last instrumentality serving, at thetermination.ofmits operation, to initiate motionof the firs-t ,instrumentality:in.the series, thus rendering -the 2,963,069 Patented Dec. 6, 1960 2 machinecontinuously operable through successive .cycles of operation indefinitely until all formingoperations on a giventubing length have been completed.

The-provision of an apparatus of the character briefly outlined above being among the principal objects of the invention, other objects and advantages, not at this time enumerated, will become readily apparent as the-following description ensues.

Inthe accompanying five sheets of drawingsforming a part of this specification, an exemplary form of. the invention has been shown.-

In these drawings:

Fig. l is a fragmentaryperspectiveview of .a forming apparatus constructed in accordance with the principles of the present inventionand showing a pipe section undergoing deformation operatively associatedwith the machine;

Fig.. 2. isa fragmentary perspective view, partly in section, of a portion of the apparatus shown in Fig. l and illustrating. the manner in which the tube section undergoing forming is intermittently advanced, while at the same time being turned circumferentially about its; own axis;

Fig. 3 is a fragmentary schematic perspective view showing the pneumatic operating instrumentalities by means of whichcertain machine functions are performed, together with the electrical control apparatus .bymeans of which these pneumatic .instrumentalities are operated;

Fig, 4 isa fragmentary-perspective view of a length of composite heat. exchange tubing embodying the-principles of-the present invention;

, Fig 5' is a fragmentary perspective view ofan inner heat exchange; tubing section which has been formed from cylindrical rod stock in accordance with the.principles of the invention;

Fig. 6 is a sectional view taken substantially along;the Vertical-plane indicated by the line 6 6 of Fig; 1;

Fig. 7 is a sectional view taken substantially, along;the line 77 of Fig. 6;

Fig. 8 is asectional view takensubstantially alongthe line 88 of Fig. 6;

Fig. 9 is a sectional view taken substantially along the line 9-9 of Fig; 8;

Fig. 10 is a sectional'view taken substantially along the line 10-40 of Fig. 8; and

Fig. 11 is a combined circuit diagram and schematic view illustrating the operation of the apparatus and the electrical control instrumentalities by means of which such operation is carried out.

THE COMPOSITE HEAT EXCHANGE TUBING Referring now to the drawings in detail, and in particular to Figs. 4 and 5, a length of composite heat exchange tubing embodying a length of tube stock deformed by the apparatus of the present invention has been designated in its entirety at 10. The composite tubing is comprised of two parts, namely, an inner tube section 12 and an outer tube section 14. The outer tube section is inthe form of a length of cylindrical tube stock and the inner tube section 12 is in the form of a length of cylindrical tube stock of lesser diameter than the diameter of the outer section 10 and which has been deformed to provide a series of outwardly projecting protuberances 16 on the cylindrical wall thereof. As bestseen in Fig. 5, the protuberances' 16 extend in a series of four rows, each row extending around the tubing to provide a helix of extremely longpitch with the four helical rows extending along and around the tubing in parallelism. The protuberances' of each helical row are spaced equally alongthe tube. Each individual protuberance '16 is provided by virtue of an outward deformation of the metal of thecylindrical tubing, such deformation'being efifected by a drawing operation, utilizing suitable dies such as will be described hereinafter, and wherein the metal of the protuberance is, as a consequence, drawn out so that it is of slightly less thickness than the thickness of the main cylindrical body of the tubing.

The internal bore 20 of the tubing section 12 provides a path for the flow of one fluid medium while the annular space 18 surrounding the inner tubing section 12 provides a path for the flow of another fluid media. These fluid media may be either of a gaseous or a liquid nature, depending, of course, upon the particular use to which the tubing is to be put. Since the various protuberances 16 are pressed outwardly in the metal wall of the inner tubing section 12, no obstruction to the flow of fluid through the bore 20 is presented. The flow of fluid through the annular space 18 is restricted to some extent by the provision of the protuberances 16 and the fluid, in passing these protuberances, has a wiping effect thereon whereby intimate heat exchange contact therewith is attained. The major portion of the heat transfer between the two moving streams of fluid will take place through the smooth undeformed cylindrical portion of the wall of the inner tubing section 12, but an appreciable additional amount of heat transfer will take place through the thin walled protuberances 16 which present an increased surface area to the fluid flowing in the annulus 18. Furthermore, because of the fact that the various protuberances 16 extend in helical rows of relatively long pitch, a swirling motion will be imparted to the fluid stream in the annulus 18, thus slightly increasing the length of the path of movement thereof through the annulus. The fluid stream will, of course, not be entirely confined to flow in the helical path afforded by the various rows of protuberances 16 since the fluid is free to move circumferentially in either direction. The protuberances, however, being arranged in helical rows, have a guiding effect on the fluid stream whereby the stream, in following the path of least frictional resistance, will, as a whole, have circumferential increments of motion which direct the same generally in a helical path. The fact that the various protuberances 16 make point contact with the inner surface of the tubing section 14 minimizes loss of heat through conduction from the composite tubing.

THE TUBE SHAPING MACHINE The stationary machine framework and the tubing arbor In the manufacture of the composite tubing 10, the outer tubing section 14 is formed in the usual manner of forming tubular cylindrical rod stock, such stock being available on the market. The inner tubing section 12 is also formed from tubular cylindrical rod stock and the various protuberances 16 are pressed in the wall of the stock, utilizing male dies within the stock and cooperating female dies exteriorly of the stock. A fully automatic machine for pressing the protuberances 16 in the wall of the tubing has been illustrated in Figs. 1 to 3 and 6 to 11, inclusive. Referring now to Fig. 1, the machine involves in its general organization an elongated framework which has been designed in its entirety at 22 and including longitudinal side rails 24 and 26, respectively, and relatively short transverse end rails 28 and 30, respectively. A plurality of transverse supporting bars or plates 32 extend between the side rails 24 and 26 for supporting various machine instrumentalities, which will be described in detail presently, in their operative relationship and these supporting plates 32 may be regarded as a part of the stationary machine framework. Certain of the cross plates 32 serve to support thereon a series of standards, only two of which appear in Figs. 1 and 3, due to the fact that the medial regions of the machine are broken away in several places. Each standard 34 carries at its upper end a cylindrical sleeve 36 and an elongated tubular supporting arbor 38 extends through the various sleeves 36 and has its rear end region projecting through and secured in a vertical supporting plate 40 mounted on one of the cross plates 32. The forward end region of the tubular arbor 38 passes through a forming station F (Figs. 1 and 3) adjacent one end of the framework 22 and the arbor terminates as at 42 a slight distance forwardly of the forming station F. The internal diameter of each sleeve 36 is somewhat greater than the overall diameter of the arbor 38 so that there is an annular clearance space between the outer cylindrical surface of the arbor and the sleeve. Thus, as best seen in Fig. 3, a length of tube stock such as that shown at 44 in which the various protuberances 16 are to be formed may be telescopically and slidingly received over the arbor 38 with the tubing projecting loosely through each sleeve 36 and substantially filling the annular space existing between the sleeve and the cylindrical surface of the arbor 38. Any desired length of tubing 44 may be received on the arbor 38 for forming purposes, the specific length shown being slightly less than the length of the entire machine and with the tubing extending from the forming station F to a region adjacent the supporting plate 40.

General machine considerations Briefly, the operatively machine instrumentalities include a set of forming instrumentalities at the forming station F designed to successively form the protuberances 16 in the wall of the tubing 12 as the latter is intermittently shifted axially along the arbor 38 from left to right, as viewed in Figs. 1 and 3. These forming instrumentalities include a set of external female dies 50 which operate exteriorly of the arbor 38 and a set of internal dies 52 which operate within the arbor. The external dies 50 are operable under the control of a piston and cylinder assembly 54 which, in turn, is controlled by a solenoid valve V1 disposed at the forming station and below the arbor 38. The internal dies 52 are operable under the control of a piston and cylinder assembly 56 having a control solenoid valve V2 associated therewith. The machine further includes longitudinally shiftable clamping instrumentalities 58 in the form of a pair of clamping jaws operable when closed to firmly grip the tubing 38 therebetween.

The jaws 58 are operable between clamping positions and positions of release under the control of a piston and cylinder assembly 60 having a solenoid valve V3 associated therewith. The clamping instrumentalities including the jaws 58 are shiftable longitudinally of the arbor 38 so that when they are in their clamping position on the tubing 44, they may be shifted toward the forming station F a slight distance to carry the tubing 44 forwardly and present new surfaces on the tubing to the forming dies 50 and 52. Such longitudinal shifting of the clamping jaws 58 takes place under the control of a piston and cylinder assembly 62 having a control valve V4 associated therewith. As will be described presently, the clamping jaws 58 are capable of limited tilting movement about the axis of the arbor 38 during their forward stroke while they are in clamping engagement with the tubing 44 so that the tubing will have imparted thereto a small increment of circumferential motion each time it is advanced through the forming station F. In this manner, the previously described helical rows of protuberances are formed in the tubing.

The outer forming dies Referring now to Figs. 1, 3, and 6 to 10, inclusive, the external die mechanism 50 at the forming station F includes a pair of cooperating, transversely shiftable tube clamping and tube forming die blocks 64 and 66, respectively, which are arranged in opposition to each other on opposite sides of the tubing 44 and which are slidable between a pair of transverse guide rails 68 which extend across the side rails 24 and 26 at the forming station F. The die blocks 64 and 66 are each provided with lateral flanges 70 (Fig. 7) which extend into undercuts 72 provided in a pair of retaining strips 74 which are bolted as at 76 to the guide rails 68. A bracket 78 (Fig. 6) is bolted as-at 80 to the adjacentends of the guide rails 68 on opposite sides of. the machine, and the twobrackets 78 project upwardly. above the guide rails 24 and '26 and threadedly and adjustably. receive therethrough limit stop screws 82 which determine the retracted or open positions.of'thejaw-like clamping .and forming die blocks 64 and 66,!respectively. The die blocks 64 and 66 arenormally maintained in their retracted-or separated positions .by means of a coil spring 84 which is interposed betweenthetwo'blocks and set into respective recesses 86 formedtherein.

The d-ie blocks 64 and are. substantially identicalin configuration and the two blockspresent opposed inner meeting faces 87 (Fig. 8) adapted to meet along a parting line 88 (Fig. 6) when the die blocksare closed upon each other. The opposed faces 87 of the two die blocks are formed with generally semi-circular tube-engaging recesses 90 which constitute, in effect, clamping jaws adapted to engage the opposite sides of the tubing '44 when the die blocks are in their operative closed forming positions around the tubing. As will be pointed out in detail subsequently, the male die instrumentalities 52 at the forming station F include a series of four dies proper which operate substantially in radial planes extending at 90 to one another and which operate simultaneously to press four of the protuberances 16, into the tubing at points which are spaced circumferentially 90 around thetubing. Accordingly, to. accommodate such male dies, the recesses 90 are provided with axially aligned cylindrical socket 92 therein which provide relief areas into which the metal of one pair of diametrically opposed protuberances 16 on the tubing .44 may be pressed at the. time of the forming operation. To accommodate the other pair of diametrically opposed protuberances 16, the meeting surfaces 87 of the two die blocks 64 and 66 are formed with vertically extending grooves 94, which when the die blocks are in meeting and clamping engage ment with each other, afford relief areas similar to those provided by the sockets 92.

It has been previously stated that the two die blocks 64 and 66 are maintained in their retracted or separated positions by means of the interposed coil spring 84. In order to eifect'closing movements of the die blocks 64 and 66, each die block has formed on the lower side there of. apair of generally triangular protuberances 96 which are bestseen in Fig. 3 and which present oppositely and outwardly facing cam surfaces 98 thereon.

As shown in-Figs. 3 andi6, the.cam.surfaces 98 on the triangular protuberances. 96 are designed for cooperation with mating cam surfaces 180 provided on a yoke member 102 threadedly received'as at 103 (Fig. 7) on the upper end of a plunger, stem 104associated with the piston and cylinder assembly 54. The piston and cylinder assembly '54 is fixedly secured'to the underneathside of a suspensionplate106'which is suspended b means of tie rods ltl 'from the guide rods 24 and 26.

The piston-and cylinder assembly 54 is of conventional design and no claim is made herein to any novelty associated with the same. This assembly has been schematically shown in Fig. 11 and includes a cylinder 110 in which there is operatively disposed-a-piston112 carrying the plunger stern 104. The'control valvcVl for the assembly'54-is operatively mounted on the lower end of the cylinder 110 as a built-inunit. The valve assembly V1 includes a cylindrical valve casing 113 in which there is axially slidable a-spool-typevalve body or core 114 the opposite ends of'which are piloted as at.116 in a.

pair-of solenoid windings 118. and 120, respectively. Uponenergization ofthe winding 118,1the valve core is moved in a direction so, that compressed air or other motive fluid issuing from a source (not shown). may

be conducted through a supplyline 122 and enter the valve casing 114 from whence it may'flow to a. line 124 to move the piston 112 forwardlyand cause the yoke 102 to engage the triangular protuberances 96 and thus draw them together to force the clamping and forming die blocks 64 and 66 toward their closed position against the spreading action of the coil spring 84. When the solenoid winding isenergized, the valve core 114 will be shifted in the opposite direction to send compressed airthrough a line 126'to retract the piston 112 and yoke 102, thus allowing the die blocks and 66 tomove totheir open retracted position.

The inner forming. dies Referring now to Figs. '8'and 9, the inner forming die assembly 52 .1 comprises aseries; of four forming dies proper 128 which are formed asprotuberances and are integrally formed on the outer ends of a plurality of lever arms or figures 130 which are contained wholly within the tubular arbor 38 at the forming station F. The fingers 130 are pivoted medially of their ends on transverse pins or rock shafts 132 the ends of which are anchored within the Wall of the tubular arbor 38. The fingers 130 are disposed in opposed pairs extending at right angles to each other with two of the fingers swinging in a vertical plane and the other two fingers swinging in a horizontal plane. The dies 128 associated with the vertically swinging fingers 130 are designed for cooperation with the relief grooves 94 (Figs. 6 and 7) of the die blocks 64 and 66 While the dies 128' associated with the horizontally'swingable fingers 130 are designed for cooperation with the opposed sockets 92 formed in the die blocks 64 and 66. The tubular arbor 38 is provided with a series of four elongated slots-134 (Figs. 8, 9 and 10) which are circumferentially' arranged 90 apart and which.

are slightly longer than the extent of the various fingers 138. The slots 134 are arranged in radial register with the respective fingers 130 so that the fingers may assume retracted positions wherein the rear die-carrying ends thereof are disposed wholly within the confines of the arbor 38 with the forward or right-hand end thereof, as viewed in Fig. 8, projecting into the slots 134, and advanced positions wherein the forming dies 12% pnoject outwardly through the slots 134 into forming cooperation with the tubing 44 while the rear ends thereof are disposed wholly within the confines of the arbor 38. In order to normally maintain the fingers 130 in their retracted positions, a pair of coil springs 136'and 138 are interposed between the opposed pairs of fingers 130, respectively.

In order to actuate the forming die assembly 52, an elongated thrust rod 140 has its rear end coupled as at 142 to the plunger stem 104 of the piston and cylinder assembly 54. The thrust rod 140 projects into the rear end of the tubular arbor 38 and projects slidingly through the arbor and terminates in the vicinity of the forming station F as shown in Fig. 8. The forward end of the rod 140 is provided with a socket 144 in which there is adapted to be removably pinned a spreader element 148 having a thrust flange 150 formed thereon and provided with a tapered or conical forward end 152 adapted, when the rod 140 is in its advanced position, to enter between the rear ends of the various retracted die-carrying fingers 130 and spread these rear ends thereof radially outwardly so as to cause the forming dies proper 128 to project outwardly through the slots 134 and press the metal of the tubing 44 radially outwardly, as shown in Fig. 8, to produce the various protuberances 16 therein.

The piston and cylinder assembly '54 and its associated solenoid control valve V2are substantially identical with the piston and cylinder assembly 54 and solenoid valve V1 and it is believed, therefore, that the previously rendered description of the former will suffice for the latter. To avoid needless repetition of description, identical,

acceded reference characters have been applied to the corresponding parts of the two assemblies, including the cylinder casing, piston, plunger stem, air lines, solenoid windings, etc. As shown in Fig. 11, when the piston 112 is in its retracted position, the spreader element 148 is withdrawn from the forming dies or fingers 130 so that the forming dies proper 128 are retracted within the arbor 38. When the piston 112 is moved to its advanced position, the thrust rod 46 and spreader element 148 are moved forwardly and assume positions wherein the spreader element 148 enters between the rear ends of the various fingers 130 and causes them to be spread apart to thus force the forming dies 128 radially outwardly through the slots 134 and into forming engagement with the metal of the tubing 44, as clearly shown in Fig. 8.

The tube clamping mechanism Referring now to Figs. 1, 2 and 3, the means for periodically advancing the tubing 44 through the forming station F includes the previously mentioned clamping instrumentalities 58 which are in the form of a pair of opposed clamping blocks or jaw members including an upper clamping block 160 and a lower clamping block 162 which is movable toward and away from the clamping block 160. The blocks 160 and 162 present to each other semi-cylindrical clamping jaws proper 164 and 166, respectively. The entire clamping assembly 58 is operatively mounted upon a swingable jaw supporting carriage 168 which is in the form of a cage-like structure of generally U-shape design in vertical longitudinal cross section and including vertical members 170 and 172, respectively, and a horizontal base member 174. The upper ends of the vertical members 170 and 172 are conncctcd together by the upper jaw member 160 which is fixedly secured thereto and the entire carriage 168 is mounted for limited swinging movement about the axis of the arbor 38 by means of trunnions 176 and 178 supported in a pair of spaced standards 182 ad 184 suitably bolted as at 186 to the side rails 24 and 26. The arbor 38, thrust rod 140, and a section of tubing mounted on the arbor pass through the trunnions 176 and 178 and standards 182 and 184. The carriage assembly 168 is capable of limited swinging movement through a small angle about the axis of the arbor 38 for purposes that will appear presently.

The lower jaw member 160 is movable vertically toward and away from the upper jaw member 160 under the control of the piston and cylinder assembly 60 and its associated valve V3. The assemblies 60 and V3 are substantially identical with the previously described assemblies 54, V1 and 56, V2, and again, to avoid needless repetition of description, identical reference numerals have been applied to the corresponding parts of these assemblies. The jaw member 162 is carried at the upper end of the plunger stem 104 and the cylinder 110 is operatively mounted upon the horizontal portion 174 of the carriage 168 so that the piston and cylinder assembly 60 and the valve assembly V3 are movable bodily with the carriage during the swinging movements of the latter. It will be seen, therefore, that when the piston 112 of the assembly 60 is in its retracted position, the lower jaw 162 will be out of engagement with the tubing 44 and that when the piston is in its advanced position, the plunger stern 104 and jaw member 162 will assume elevated positions wherein the jaw member engages the tubing 44 and, in combination with the upper jaw member 160, firmly clamps the tubing so that the latter is constrained to follow the longitudinal shifting movements of the cariage 168, as well as the swinging movements thereof.

The carriage 168, in addition to being capable of limited swinging movements about the axis of the arbor 38, is also capable of limited axial shifting movement or reciprocation longitudinally of the arbor 38. Toward this end, the trunnions 176 and 178 are capable of both rota- 8 tional and axial sliding movement within the bearing 180. During forward movement of the carriage 168, a small increment of lateral swinging movement is adapted to be applied to the same by means of a pair of cooperating cam surfaces 186 and 188 provided on the horizontal member 174 of the carriage 168 and on a cam block 190 suitably mounted on a stationary part of the machine framework. A spring 192 extends between a pair of anchoring pins 194 and 196 on the framework and carriage, respectively, and serves to normally maintain the carriage in its non-tilted position wherein a limit stop finger 198 mounted on the vertical part 170 engages one of the transverse crosspieces 32.

The jaw-supporting carriage reciprocating mechanism In order to efifect longitudinal movements of the carriage 186 in opposite directions for the purpose of feeding the tubing 44 to the forming station F, the piston and cylinder assembly 62 and its associated valve structure V4 are operatively secured to an angle piece 200 which is bolted as at 202 to a horizontal bridge member or plate 204 which extends across the upper ends of the standards 182 and 184. The assemblies 62 and V4 are similar to the previously described cylinder and valve assemblies and need not be described in detail herein. The plunger stem 194 of the piston and cylinder assembly 62 is guided in a block 205 mounted on the plate 204 and the outer end of the stem 104 carries an L-shaped member 206 having a vertical leg 208, the lower end of which is slotted as at 210 to provide apair of yoke arms 212 which straddle the upper end of the vertical side plates 170 of the carriage 168 so that the carriage as a whole is constrained to follow the longitudinal shifting movements of the member 206. Thus, it will be seen that when the piston 112 of the piston and cylinder assembly 62 is in its retracted position, the carriage 168 and its associated clamping members and 162 will assume a retracted position wherein the carriage as a whole extends substantially vertically, and that when the piston is in its advanced position, the carriage 168 will assume a forward position wherein the cam surfaces 186 and 188 are in engagement with each other and wherein, as a consequence, the carriage will assume a tilted or inclined position. It will be understood, of course, that the operation of the two piston and cylinder assemblies 60 and 62, respectively, will be correlated with each other so that during the return motion of the carriage 168, the clamping jaws 160 and 162 wil be opened while, during the forward motion of the carriage, these jaw members will be maintained in their closed positions.

THE ELECTRICAL CONTROL INSTRUMENTALITIES The various phases of machine operation involving actuation of the piston and cylinder assembly 54, 56, 60 and 62 are operable under the control of a series of seven pairs of normally open contacts disposed in a circuit arrangement in such a manner that each pair of contacts upon closure thereof establishes an electrical circuit through one or more of the solenoid actuated valves V1, V2, V3 or V4. The various pairs of contacts are successively operable, each pair of contacts awaiting completion of the operation or operations initiated by the preceding pair of contacts, and the last pair of contacts in the series initiating machine operations which, upon completion thereof, effect closing of the first pair of contacts in the series so that the machine operation is continuous and repetitive. The various pairs of contacts are mechanically actuated by means of actuating fingers which are movable bodily with a moving machine instrumentality so that no relay devices, time delay or holding circuits or other electro-mechanical instrumentalities are required. The various pairs of contacts are designated at S1, S2, S3, S4, S5, S6 and S7 in Fig. 11. During machine operation, these contacts are adapted to become sequentially closedin the order named andthe sequentialclosingthereof may be regarded one complete machine, cycle. The various contacts S1 to "S7, inclusive, may be, in thejform of conventional microswitches, which are suitably mounted on the machine framework at appropriate points where they may be actuated upon engagement by the moving machine instru mentalities with which they are associated. The contacts S4 and S2 are associated withthe, piston and cylinder assembly 54 and aremounted on the framework in spaced relationship wherein they areengageable by an actuating finger 220, carried and movablebodily with they plunger 104. Theco-ntacts S1 and'S6 .are operatively associated with the piston and cylinder assembly'621 and are similarly adapted to-be engaged by aplunger-carried actuating finger 222. Theco-ntacts S32 are engageable by a plunger-carried actuating finger 224 associated with the piston and cylinder assembly 56.. The contacts S7 and S are, engageable with} an actuatingfinger'.226 carried by the plungersteml0'4 of thepiston and'cylinder assembly60.

THE OPERATION OF MACHINE In the operation of the machine, a selected length'of theltubingg4-4is applie'dto the arbor34" bytelescoping the tubing over the, arborjfrom'the'right-hand 'endof the machine as viewed inFiggl 'and causing-the tubing to bethreaded through the-various sleeves 36pcarried at the upper ends of'the standardsj34. If:the-tubing is sufliciently lon ,:the rear end thereof -willextend to a region adjacent the coupling .142 at the rear end-of. the machine. Prior tothe'tirne'thatthetubing '44 is inserted upon the,arbor 38, thelatter maysag to a slightdegree so that it is' supported on the:bottom regions "of-the various bores provided in the sleeves'fifi; "Howevenas'the'mbing is threaded through each sleeve 36,='th'e "arbor'will be raised intoconcentric relationship with the sleeve.

Upon closure of the master switch MS (Fig. 11), current will be supplied to the main lines 11 and 13 and will become availablelforlall, machine-- operations. Each piston 112 of'the variouspiston and cylinder assemblies 54, 56, "60 and 62 isnormally maintained slightly in advance -of its fully retractedposition-by meansiof a coil springgg228 so that the, various operating fingers 22%), 2,22,2'224 and; 22,6 normallyare outof' contact with their respective pairs of contacts. Thus, in order to commence machine: operations, ,it is necessarvto manuallylclose a start switch Ss, whereupon a circuit will be established from the negative side of the line 11 through lead; 15, 17, 19, start switch Ss, lead 21, forward solenoid winding 118 of the valve V1, and leads 23 and 25 to the posi tive side of the line. Energization of the winding 118 will permit air to flow from the source 122 through the valve V1 and line 124 to one end of the cylinder 110, whereupon the piston 112 thereof will be advanced and the yoke 102 moved upwardly (Fig. 4) into engagement with the triangular protuberances 96 so that the outer die blocks 64 and 66 will be drawn together in the manner previously described, thus enclosing a limited portion of the tubing 44 therebetween preparatory to actuation of the internal die-carrying fingers 130. At the time that the plunger stem 104 moves to its extreme advanced or forward position, the actuating finger 220 will engage and close the pair of contacts S2 whereupon a circuit will exist from the line 11 through leads 27, 29, contacts S2, leads 31, forward winding of the solenoid valve V2 and leads 33 and 35 to the line 13. Energization of the winding of the valve V2 will establish communication between the source of air and the conduit 124 so that air will be admitted to the cylinder of the assembly 56 to drive the piston 112 thereof forwardly, thus forcing the thrust rod 140 forwardly and causing the spreader member 148 to enter between the rear ends of the various pivoted die-carrying fingers 130, whereupon the male dies proper 128 will be forced radially outwardly ,by a carnming action. and into engagement with 'thewmetalioflthe tubing 44jto create'four ,circumrferentially spaced protuberances 16in the wallgat the forming station. At-the time thatflthe plungerjzstern'llfll of the piston and cylinder assembly 56 moves toiits e x treme forward position, the'finger 224-engages and closes the pair of contactsSS whereupon a circuit will exist'from the line 11' through lead37, contacts S3,'leads-'39, 41, reverse winding of the solenoid.valve V1, and leads 43, 25, to'the line 13. At theisame time, a second circuit will be establishedfrom the line 18 through lead 37, contacts 783, leads 39, 45, reverse winding of the solenoidvalve V2 and leads 47, 352to the.line 13.

Energization ofthe. reverse windings of the two solenoid valves'Vl and V2'wil1 cause the admission ofair through the lines 126 to'retract the pistons 112 of the two assemblies 54 and 56, respectively, so .that theyoke 102 will be retracted and'the outer die blocks 64 andfl66 moved-to their openedrpositions while at'the same time the thrust'140'will be retracted to release the die-carrying fingers and-allow them to move to their retracted positions within the arbor 38. Upon retraction of the yoke 102, the finger 220 will engage and'close the pair of contacts S4 w'herellPOn a circuit will exist from the line 11 throughlea'ds27, 49, contacts S4, lead 51 and forwardwinding of the solenoid valveV3, whereupon air Will be-admitte'd through the line124 through a cylinder 110 of"the piston and'cylinder assembly 60 to drive the piston 112 forwardly and cause the. movablelower jaw member1'62 to move into clamping cooperation with the upper jaw member 1'60'firmly clamp the tubing 44 there, between. Upon-movement of the jaw. member 162 into engagement with the tubing 44, the finger 226 will engage the contacts S5 and close the same whereupona circuit will exist .from thelinell throughleads"57,'59, con tacts S5, lead161, forwardwinding of the solenoid'valve V4, and,lea'ds 63,165to the line'13; 'Energization of the forward winding of the valve V4 will admit airthrough the line 124 "of the piston and cylinder assembly 62; thus moving the plunger stern 104" forwardly andcausing the L-shaped member'206 and its yoke arms 212 to shift the carriage 168 forwardly. Since the clamping jaw members and 162 are movable bodily with the'car} riage168 and since these clamping members are closed upon the tubing 44, the tubing will he slid forwardly, and a limited portion thereo-ffed into the forming zone F. At the same time that the tubing 44 'moves forwardly, the cam surfaces 168 and 188 on the horizontal member 174 and cam block 190, respectively, will move into engagement thus causing the entire carriage 168 and the clamping members 160 and 162 carried thereby to tilt slightly about the axis of the arbor 38 so that the tubing 44 will be rotated throughout a limited circumferential extent. Such rotation of the tubing 44 will cause a series of fresh surface regions on the wall of the tubing 44 which are slightly ofiset circumferentially as well as axially from the previously formed series of four protuberances to be presented to the forming dies. As the carriage 168 reaches the limits of its forward motion, the actuating finger 222 will engage the pair of contacts S6 and close them, whereupon a circuit will extend from the line 11 through leads 15, 67, contacts S6, lead 69, reverse winding of the solenoid valve V3, and leads 71, 55 to the line 13. Energization of the reverse winding of the valve V3 will admit air through the line 126 to the cylinder 110 of the assembly 60 to return the piston 112 and clamping block 162 to their retracted positions, thus releasing the tubing 44. Return of the piston to its retracted position will cause the actuating finger 226 to engage the pair of contacts S7 and close the same whereupon a circuit will exist from the line 11 through leads 57, 73, contacts S7, lead 75, reverse winding of the solenoid valve V4, and leads 77, 65, to the line 13. Energizas tion of the winding of the solenoid valve V4 will cause air to be supplied through the line 126 to the cylinder macer- 110 of the assembly 62, thereby retracting the carriage 168 and causing the actuating finger 222 to engage and close the pair of contacts S1.

Since the contacts S1 are disposed in a local circuit in parallel relationship with respect to the start switch Ss, closure of the normally open start switch Ss so that the cycle of operations previously described will be repeated. The various machine cycles will be repetitive as long as the master switch MS remains closed. During the operation of the machine, the tubing 44 will be intermittently advanced through the forming station and rotated throughout a slight angle during each advancing operation. The tubing will continue to move until the entire length thereof has passed through the forming station F, after which the master switch MS may be openzd and a new length of unformed tubing 44 applied to the arbor 38 preparatory to further machine operations.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as variouschanges in the details of construction may be resorted to without departing from the spirit of the invention. Only insofar as the invention has been particularly pointed out in the accompanying claims is the same to be limited. For example, while in Figs. 4 and 5 the inner tubing section 12 is shown as being provided with outwardly pressed protuberances 16, it is within the purview of the present invention to form this inner section of smooth cylindrical stock devoid of protuberances and to press indentations or protuberances in the wall of the outer tubing so that these protuberances project inwardly and engage the smooth surface of the inner tubing section 12. In such an instance, suitable rearrangement of the die instrumentalities 50 and 52 will be resorted to.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. In a machine for forming outwardly pressed tapered protuberances in the wall of a. length of cylindrical tube stock, in combination, an elongated framework, a tubular arbor mounted on said framework and adapted to telescopically and slidably receive thereover the tubing to be formed, means adjacent one end of said arbor establishing a forming station, said arbor projecting through said forming station, a series of substantially radially extensible and contractible forming dies mounted on said arbor for substantial radial movements in unison, said dies being movable between retracted positions wherein they are disposed wholly within the cylindrical confines of said 12 arbor and the tubing surrounding the same and advanced positions wherein they project outwardly beyond the cylindrical confines of the arbor and engage the tubing on the arbor to press respective protuberances in the wall thereof, a cam surface on each die, a thrust rod slidable Within said arbor and carrying at its forward end a tapered spreader element engageable with said cam surfaces simultaneously for actuating said dies, said thrust rod projecting outwardly beyond one end of the arbor, a series of outer forming dies mounted on said framework, said outer dies being movable between retracted positions wherein they are out of register with the inner dies and advanced positions wherein they are in such register and wherein they encompass the tubing on the arbor, means for moving said outer forming dies, a carriage mounted for longitudinal shifting movement in opposite directions axially along said arbor and for limited rocking movement about the axis of the arbor, cooperating clamping jaws on said carriage and movable bodily with the carriage, said jaws being relatively movable between closed positions wherein they engage the tubing on the arbor therebetween and open positions wherein they release the tubing, means for moving said carriage axially, cam means positioned in the path of movement of said carriage for deflecting the same laterally to effect limited rocking thereof about the axis of the arbor during forward movement of the carriage, means for actuating said clamping jaws, and means for actuating said thrust rod.

2. In a machine for forming outwardly pressed tapered protuberances in the wall of a length of cylindrical tube stock, the combination set forth in claim 1 including, additionally, control means for effecting sequential operation of said clamping jaw actuating means, said carriage moving means, said outer die moving means, and said thrust rod actuating means in the order named.

References Cited in the file of this patent UNITED STATES PATENTS 1,717,487 Armstrong June 18, 1929 1,773,522 Delery Aug. 19, 1930 2,142,017 Riemenschneider Dec. 27, 1938 2,148,221 Schneider Feb. 21, 1939 2,447,909 Hunziker Aug. 24, 1948 2,658,548 Harrison Nov. 10, 1953 2,756,032 Dowell July 24, 1956 2,806,677 Jacobs Sept. 17, 1957

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