US2468717A - Automatic multiple twisting machine - Google Patents

Description

April 1949- 0. WENNBERG AUTOMATIC MULTIPLE TWISTING MACHINE 6 SheetsSheet 1 Filed Aug. 14, 1945 INVEN TOR.

April 1949- o. WENNBERG 2,468,717

AUTOMATIC MULTIPLE TWISTING MACHINE 6 Sheets-Sheet 3 IN V EN TOR.

O. WENNBERG AUTOMATIC MULTIPLE TWISTING MACHINE April 26, 1949.

Filed Aug. 14, 1945 o. WENNBERG 2,468,717

AUTOMATIC MULTIPLE TWISTING MACHINE 6 Sheets-Sheet 4 April 26, 1949.

Filed Aug. 14, 1945 P 26, 1949. o. WENNBERG AUTOMATIC MULTIPLE TWISTING MACHINE 6 Sheets-Sheet 5 (PMMN QNN o s Filed Aug. 14, 1945 INVENTOR.

April 26, 1949- o. WENNBERG AUTOMATIC MULTIPLE TWISTING MACHINE 6 Sheets-Sheet 6 Filed Aug. 14, 1945 INVHVTOR.

Patented Apr. 26, 1949 UNITED STATES PATENT oI=I=IcE 2,468,717 AUTOMATIC MULTIPLE TWISTING MACHINE Odd Wennberg, Manhasset, N. Y. Application August 14, 1945, Serial No. 610,713

16 Claims. 1

This invention relates to machines for twistin metallic bars or rods and, more particularly, for helically twisting and stretching steel bars or rods for use in concrete reinforcement and the like, as shown, for example, in U. S. Patent No. 2,142,758 to Andrea Ossoinack and U. S. Patent No. 2,256,060 to Joseph D. Stites.

The object of the present invention is to provide a machine for twisting a plurality of such bars simultaneously whose operation is substantially automatic and whereby the twisting of the bars or rods will be effected with maximum efficiency. The invention contemplates the provision of novel mechanisms and controls by which the twisting operation is automatically controlled in accordance with predetermined requirements.

A further object is to provide a multiple twisting mechanism in which the clamping means clamping one end of the bars or rods to be twisted remain stationary during the twisting operation while the twisting heads clamping the opposite ends of said bars or rods are rotatable and moved into twisting position by hydraulic means.

Another object of the present invention is to provide novel clamping and twisting heads from which the jaws may be easily and quickly removed without dismantling the heads proper.

With these and other objects in view, to be pointed out in the specification and especially in the appended claims, one form of a multiple twisting machine, in which the invention may be conveniently embodied in practice for twisting three bars simultaneously, has been illustrated in the accompanying drawings, in which? Fig. 1 is a plan view of a complete multiple twisting machine, showing the headstock with the rotatable twisting heads, lifting mechanism, conveyors, and tailstock with the stationary clamping heads in their respective spaced relationship.

Fig. 2 is a front elevation of the machine, shown in Fig. 1.

Fig. 3 shows an enlarged section through the machine on line 3-3 of Fig. 1, illustrating in greater detail the conveyors for the bars to be twisted, the rotatable twisting heads, and the lifting mechanism.

Fig. 4 is an enlarged front elevation, partly in section, of the headstock carrying the rotatable twisting heads.

Fig. 5 depicts an end view of the headstock shown in Fig. 4.

Fig. 6 is a still further enlarged fragmentary sectional front view of one of the rotatable twisting heads with part of the hydraulic motor for opening and closing the jaws.

Fig. '7 is an enlarged fragmentary sectional view of the remainder of the hydraulic motor. part of which is shown in Fig. 6.

Fig. 3 is an enlarged fragmentary and partially sectional front view of the stationary clamping heads mounted on the tailstock of the machine.

Fig. 9 is a partially sectional front view of the counting device, which is attached to the headstock.

Fig. 10 is a sectional end view of the counting device, shown in Fig. 9, and its hydraulic resetting mechanism.

Fig. 11 is a diagrammatic view which shows the electric and hydraulic circuits and controls in connection with the complete layout.

Fig. 12 shows diagrammatically and in greater detail the arrangement and wiring of a reversing switch employed in the electric circuit illustrated in Fig. 11.

Referring to Figs. 1 and 2, the multiple twisting machine shown is adapted for twisting a plurality of bars or work-pieces simultaneously in a successive series of operations and consists primarily of a main frame a twisting station, which comprises a tailstock 22 with clamping heads 86, 81, and 88 for engaging one end of the bars, a headstock 2|, carrying rotatable clamping heads 5|, 52, and 53 adapted to grip the opposite ends of said bars at a level contrasting to the level of the first clamping heads, and a lifting and centering device 23, adjacent to headstock 2|, adapted to lift and locate said opposite ends of the bars in alignment with the rotatable clamping heads; and a multiplicity of electricallyactuated, transverse and spaced-apart conveyors 24 for receiving and conveying the bars to predetermined positions at said twisting station.

H eadstock Figs. 3, 4, and 5 show in greater detail headstock 2|, which is mounted on sub-base 26, adapted to be moved along main frame 20 to locate headstock 2| in clamping and twisting relationship to the ends of the bars to be twisted. The longitudinal movement of sub-base 26 is guided by flanged pins 21 in recesses 28 of brackets 20, suitably fastened to main frame 20 near each of the four corners of sub-base 26. A channel section 30, or the like, transversely extending between longitudinal H-beams of main frame 2| and suitably attached thereto, carries a hydraulic motor 3| for shifting headstock 2| on subbase 28 with respect to lower base 20. Hydraulic motor 3| comprises a cylinder 34 with front and rear ports 33 and 32, respectively. Piston 31, in slidable engagement with said cylinder 34, carries piston rod 39, which is pivotally connected to bracket 39, conveniently fastened to sub-base 26.

Pressure fluid is supplied by a hydraulic pump 235, operatively connected with electric motor 229, both of which are secured to oil tank I21, which forms a part of or is suitably connected to lower base 29. When pressure fluid is directed into rear port 32 of hydraulic motor 3|, piston 31 will be urged to the left and move sub-base 29, carrying headstock 2|, into its working position, which is reached when front face 26 of said sub-base 26 comes to rest against the rear faces of brackets I83 and I84, fast to base 29 (Figs. 4 and 5). In this position, sub-base 29 actuates a limit switch 295, mounted on a bracket I49, which is shown fastened to stop or bracket I93.

An electric motor 25, with its spring-set magnetic brake 49, is carried on sub-base 29. Power shaft U of motor 25 is operatively connected with input shaft 42 of headstock 2| by coupling 49. Shaft 42 is rotatably supported in bearings 44 and 45, respectively, in rear and front walls of gear box housing 49 and carries a pinion 41, suitably fastened thereto by key 48 or the like (Fig. 6). Said housing 46 is secured to sub-base 29 in any suitable manner. Pinion 41 meshes with a gear 49, fixedly connected to a hollow spindle 59, which forms part of the rotatable, centrally located twisting head 5|. Twisting heads 52 and 53, respectively, arranged in the same horizontal plane as twisting head 5| (Fig. 3), are of identical arrangement as twisting head 5|. Their respective drive gears, which have the same number of teeth and the same pitch as gear 49 of twisting head 5|, mesh with said gear 49 on respective opposite sides thereof. Consequently, since the rotating direction of twisting head 5| (Fig. 5) is in counter-clockwise direction, the rotation of twisting heads 52 and 53 will be in clockwise direction.

Spindle 59 is rotatably held in bearings 54 and 55, respectively, which are mounted in opposite walls of housing 46 and in the same vertical plane as said input shaft 42, but somewhat lower, consistent with the pitch diameters of pinion 41 and gear 49.

A shaft 59 is slidably mounted in annular bushings 51 and 58 in hollow spindle 59 (Fig. 6) and carries at its left end a pivot bracke u 59, fastened thereto in any convenient manner. Jaw-holder actuating links 69 and 69, respectively, pivotally connect said bracket 59 to upper and lower jawholders 92 and 62, respectively, whose flanged inclined surfaces SI and SI are adapted for sliding engagement with corresponding recesses 93 and 93' in spindle head 91, suitably fastened to the left, enlarged end 98 of spindle 59 by means of bolts or the like. Wedge-shaped jaw- holders 92 and 92 are provided with dovetail-shaped transverse recesses 12, in which similarly shaped jaws 94 and 94 are suitably fastened by means of screws, such as 99 shown for the lower jaw 94 in Fig. 6. The gripping edges of jaws 94 and 94' and their general shape are designed preferably as disclosed in Fig. 8 of my U. S. Patent No. 2,217,- 301. Shaft 58 depends from a piston 19, slidable in a cylinder 1|, which may form a part of or be fixedly connected to hollow spindle 59 at its right-hand end; hence, cylinder 1| will participate in any rotary movement of hollow spindle 59.

Cover 13 is bolted to or otherwise suitably connected with cylinder 1| and is provided with a circular bore 14 co-axial with shaft 59. A cylindrically shaped housing 15, with its end cover 19, pressure ports 11 and 19 and drain port I53, carries a pintle 19 in rotatable engagement. Drain port I59, with suitable piping back to tank, serves to take care of any leakage between housing 15 and pintle 19. Pintle 19 extends through bore 14 of cover 13. The left face of flange 99 of pintle 19 is clamped against cover 13 by member 92. The right face of flange 99 slidably engages a corresponding shoulder II of housing 15. At its opposite end, pintle 19 is located against lateral movement with respect to cylinder 15 by lock washer 94, which is in slidable engagement with a face of cylinder 15.

To close the open jaws 94 and 94, shown in solid lines in Fig. 6, in order to bring them into the position shown in dotted lines, the pressure fluid is pumped through port 19 and annular passage I 52 in cylinder 15 to passage I59 in pintle 19, exerting pressure against the right-hand end of piston 19 and thereby pushing it towards the left. The fluid in cylinder 1| to the left of the piston will be forced back to tank at negligible pressure through communicating passages I51 and I59 in cylinder 1| and cover 19, respectively, annular groove I55 in cover 19, passage I54 in pintle 19, annular groove I5I in cylinder 15, and port 11.

To open the jaws (piston 19 now being in its extreme left position), pressure fluid is directed through port 11, annular groove I5I, passages I54, I59, and I51, thereby urging piston 19 towards the right until it has again reached the position shown in Fig. 6. The fluid to the right of piston 19 will be discharged to tank through passage I59, annular groove I52, and port 19.

Spindle 59 is rotated during certain predetermined periods in the operating cycle. Cylinder H and pintle 19 will participate in any such rotation of spindle 59. However, housing 15 will remain stationary at all times, because pintle 19 is in rotatable engagement with housing 15. In order to guide slidable piston 19 and to prevent any relative angular movement between the latter and cylinder 1 I, a suitable guide pin I99 is in slidable engagement with corresponding bore I59 of piston 19 and located in recesses I99 and IGI of cylinder 1| and cover 13, respectively.

The front face of conically shaped spindle head 91 is preferably provided with a transverse recess or slot of suilicient size, and adapted to permit removal of the jaws 94 and 94' in their closed position after loosening holding screws 99, without dismantling the mechanism, thereby facilitating an easy and quick change of these gripping jaws, which inherently are subject to considerable wear and may require frequent replacement.

Tailstock The tailstock 22 rests on main frame 29 at the end opposite of headstock 2| and comprises three clamping heads 99. 91, and 99, as shown in Fig. 1, each of which is in the same vertical plane as its corresponding rotatable twisting head 53, 5|, and 52, respectively, but in a slightly lower horizontal plane than the latter, the reason for which will be more fully explained hereinafter. The clamping heads 99, 91, and 99, as well as hydraulic pump 234, operatively connected with electric motor 225, are secured in any suitable manner to the right-hand part of a sub-base 99, which is completely enclosed and serves as a tank or reservoir for pump 234. It should be noted that a separate fluid pressure source is provided near the tailstock for practical reasons only, namely, to keep the hydraulic piping to a minimum. If desired, all hydraulic motors and controls of the machine may be supplied by one fluid pressure source. The right-hand portion of sub-base 99 is provided with brackets I00, IOI, I02, and I03 to fasten the same detachably to main frame 20 by means of clamping gibs I08, bolted to brackets I00, IOI, I02, and I03, respectively, or by any other convenient clamping means. Brackets I04 and I05, forming the left portion of sub-base 99, may be anchored to base 20 in any suitable manner, such as by several bolts I06 and nuts I01, as shown. These bolts I06 may extend through brackets I04 and I05, respectively, as well as through the flanges of H-beams 35 of main frame 20.

Tailstock 22- may be selectively anchored at different spaced-apart points along main frame 20 to accommodate varying lengths of bars. For roughly adjusting tailstock 22 along base 20,the top surface of the latter may be provided with a series of holes I09, suitably spaced apart, as shown in Fig. 2. When moving tailstock 22 on sub-base 99, bolts I06 and nuts I01 are removed and gibs I08 loosened. Sub-base 99 then may be moved along main frame 20 into any position where bolt holes in brackets I04 and I05 and holes I09 of base 20 are in alignment; gibs I08 are then tightened and brackets I04 and I05 anchored to base 20 by means of bolts and nuts I06 and I01. It will be understood, however, that this adjustment may only roughly give the desired distance between headstock and tailstock.

Anchoring brackets I04 and I05 are rigidly interconnected by upper and lower cross-members H and II I, between which bearing H2 is fixed substantially in the longitudinal center line of the machine (Fig. 8). Partly threaded shaft H3 is rotatably mounted in bearing H2 and located against longitudinal movement relative to bearing II2 by locking collar II4 on the righthand side and by abutting nut M5 on the left side of bearing II2. Abutting nut II5 may be fixedly connected to shaft I I3 by pin I I6 or other suitable means. The right-hand threaded portion of shaft II3 cooperates with a similarly threaded nut II1, fixedly attached to sub-base 99, as shown, or in any other convenient manner. Threaded shaft 3 extends into the in" terior of sub-base or oil tank 99, but is separated from the oil by chamber II9, adapted to receive shaft I I3 through a suitable opening in rear wall II 8 of sub-base 99. It will be noted that shaft II3, terminating at its left end in a square section I20, forms a rigid but adjustable link, which connects the left-hand structure, including brackets I04 and I05, with the right-hand part of sub-base 99, carrying stationary clamps 86, 81, and 88 and pump 234 with electric motor 225.

As previously pointed out, a rough adjustment of tail-stock 22 may be effected by moving the complete sub-base 99 into registry with suitable pairs of holes I09, provided along the main frame 20. Since the length of the threaded portion of shaft H3 is in excess of the distance between adjacent holes I09 in frame 20, clamps 86, 81, and 88 may be placed in any desired position on main frame 20 by turning square end I20 of shaft I I3, whereby the relative distance between the right and left-hand parts of sub-base 99 is changed.

The bars to be twisted are loaded on conveyors 24, to be fully described hereinafter, and fed sideways into clamping heads 86, 91, and 99 in such a manner that their end portions will extend a substantial distance into transverse recesses in the face of the housings, such as 89, shown in connection with clamping head 81 in Fig. 8, which is representative of all clamping heads. This is in contrast to twisting heads 5|, 52, and 53, whose transverse recesses 99 need only be of sufficient size to permit convenient removal of jaws 64 and 64', because these twisting heads 5|, 52, and 53 are shifted into clamping position over the end portions of the bars, thus obviating placing the bars inside jaws 94 and 64 by means of the conveying mechanism, as is done in connection with stationary clamping heads 86, 81, and 88. The clamping heads 86, 81, and 88 are arranged with gripping jaws 64", jaw-holders 62", and actuating links 99", similar to those described heretofore in connection with the twisting heads of headstock 2I. Pivot brackets 59' is fastened to shaft 92, slidable in annular bushings 93 and 94, mounted in a suitable circular bore of housing 89, and depends from piston 95, slidable in cylinder 96. The latter is fastened to the left flanged end 9| of housing 89 and includes fluid pressure ports 91 and 98 at its left and right end, respectively. When pressure fluid is directed through port 91, piston 95 will be moved towards the right, and the fluid in cylinder 96 to the right of piston 95 will be returned through port 98 to tank at negligible pressure. As a result, the gripper jaws 64" will be closed on the end portions of the bars to be twisted and will be positioned as shown in dashed lines. Similarly, when the jaws are closed and pressure fluid is directed through port 98, the piston 95, which is now in its extreme right position, will be moved to its extreme left position, the fluid to the left of plunger 95 will be expelled through port 91 to tank, and the jaws 64" opened to release the bars, as shown in solid lines in Fig. 8.

Conveyors A number of feeding means or conveyors 24 are spaced along the main frame 20 between headstock 2| and tailstock 22 to support the bars to be twisted at intermediate points (Fig. 1). The end portions of the bars project beyond the conveyors located at the extreme right and left, respectively. The bars are suitably loaded in three successive carrier pockets a, b, and c on the right-hand side of the machine (Fig. 3) and fed into longitudinal alignment with twisting heads 53, 5|, and 52 and clamping heads 86, 81, and 88, respectively, for clamping and twisting. The several receiving and conveying means 24 are all substantially alike, with their carrier pockets in longitudinal alignment, and are preferably driven by an electric motor I2I, mounted on oil tank I21 and arranged with magnetic, spring-loaded brake I22 for -quick stopping (Fig. 1). The output shaft of electric motor I2I carries a suitable pulley I23 and is in driving connection with pulley I24 of speed reducer I26 by means of V-belts I26. The several conveyors 24 are driven by a common shaft I28, extending from the speed reducer I 25 parallel and to one side of mainframe 20 and connected to speed reducer I25 by' coupling means, such as I29. Shaft I28 is journalled along its length in suitable brackets I30, solidly fastened to base 20.

A representative feeding mechanism is shown enlarged and in greater detail in Fig. 3. Between two adjacent brackets I30 a sprocket wheel I3I is fixed to drive shaft I28. An endless chain, formed by carrier links I32, having receiving pockets, such as a, b, and c, and connecting links :33, extends transversely of the machine and engages driving sprocket I3I and idling sprocket I34. located on the opposite side of the machine and carried by idler shaft I35, journalled in two adjoining brackets I36. The endless chain, consisting of carrier links I32 and connecting links I33, has a natural tendency to sag between driving sprocket I3I and driven sprocket I34. To guard against any undesired sagging and to locate carrier links I32 when in line with the twisting heads 53, 5i, and 52 and with clamping heads 86, 81, and 88, respectively, supporting rolls I50 are arranged which engage the lower surface of the endless chain and which are journalled in brackets I68. As shown in Fig. 3, the brackets I68 may be carried by a cross-member I93, fastened to the upper flanges of H-beams 35.

It will be noted that one pocket remains empty between the three pockets in alignment with the twisting heads and the loading pockets a, b, and c. Consequently, in order to convey the bars loaded into pockets a, b, and c into alignment with twisting heads 53, 5|, and 52, respectively, it will be necessary for the endless chain to ad- Vance a distance equivalent to four pockets during each operating cycle, and for this reason driving sprocket I3I and idler sprocket I34 are provided for convenience with a multiple of four teeth each, or, for instance, with eight teeth each, as shown. To stop electric driving motor I2I, when the loaded pockets a, b, and c are in registry with twisting heads 53, 5|, and 52, respectively, the idler sprocket I34 is provided with two diametrically spaced-apart cams I31 and I38, which are adapted to actuate alternately arm 22I of a spring-returned limit switch I39, as will be fully described hereinafter. After the twisted rods have been released by the jaws in twisting heads 53, 5|, and 52, they drop into the pockets of the endless chain in registry with these heads, and when a new batch of untwisted rods is advanced into alignment with the twist ing heads, the previously twisted rods are carried by the conveyor to the left or unloading side of the machine, where they may be dropped in a chute (not shown) or taken off by hand, as desired.

As shown in Fig. 3, the bottoms of the pockets in carrier links I32 are located somewhat below the level of the horizontal center line of the rotatable twisting heads 53, 5I, and 52, but at approximately the same level as the stationary clamps 86, 81, and 88 (Fig. 2), so that the bars are fed directly into clamping position relative to the latter. Hence, when the bars are gripped in the stationary clamps and in the rotatable twisting heads, they will be at a slight slope during the twisting operation and are therefore prevented from chafing on the pockets in links I32 of conveyors 24. It must be realized that one end of the bars is held fixed during the twisting operation by means of the stationary clamps 86, 81, and 88. The twisting force is exclusively provided by the rotatable twisting heads 53, 5|, and 52, which may rotate at considerable speeds. The twisting torque of rotatable heads 53, 5|, and 52 is transmitted through the whole bars, and, inasmuch as the clamps 86, 81, and 88 hold the ends of the bars stationary, the twisting deformation will begin there and will travel at a comparatively slow rate along the bars towards their rotating ends, which are gripped in the rapidly rotating twisting heads 53, 5|, and 52. It is, therefore, desirable that no portion of the bars is in contact with the pockets of any of the conveyors 24 during the actual twisting operation, to avoid the previously described chafing, which might even cause the bars to break on account of the high stresses present due to the combined twisting and stretching action.

Centering device After either one of cams I31 and I38 has stopped the conveyor motor I2I and, hence, the conveyors 24 by actuating limit switch I39, as previously described, the end portions of the bars adjacent to the twisting heads 53, 5|, and 52 are lifted to the level of said twisting heads by means of lifting and centering device 23.

A structural member I62 (Fig. 4) extends between opposite sides of main frame 20 and rigidly supports a hydraulic cylinder I63, having left and right-hand pressure ports I64 and I65 and carrying a piston I66 in sliding engagement. Left-hand end I14 of piston rod I61, depending from piston I66, pivotally engages one end of connecting links I69, whose opposite ends pivotally engage a bell crank I10, fastened by a key or the like to a transverse rocker shaft I1I, which is journalled in bearings I12 and I13, mounted in opposite sides of lower base 20 (Fig. 5). Double-ended rocker arms I15 and I18, fixed to the right and left ends, respectively, of shaft I11 and provided with two longitudinal slots each I11 and I18, are pin-connected on their one end to connecting rods I19 and I and on their other end to connecting rods I8I and I82, respectively. Brackets I83 and I84, serving also as stops for locating sub-base 26 in its working position, carry connecting rods I19 and I8I and connecting rods I80 and I82, respectively, in slidable and spaced-apart relationship. Lower cross-bar I40 rests in the fork-like upper ends of connecting rods I19 and I80 and is fixedly fastened thereto by bolts or the like. Connecting rods I8I and I82 have fastened to their upper ends brackets I81 and I88, respectively, which project longitudinally of the machine and end in vertically positioned bosses I89 and I90, whose center line is substantially in the same vertical plane as the axes of connecting rods I19 and I80; to each side of bosses I89 and I80, crossbars I9I and I 92 are suitably fastened by bolts or the like.

The lower cross-bar I40 carries three troughshaped lifting members I4I, I42, and I43 in alignment with rotatable twisting heads 53, 5I, and 52, respectively. Each of these lifting members consists of two similarly shaped plates, fastened in pairs to the front and to the rear of crossbar I40, respectively, forming between them a. recess into which centering members I44, I48, and I46, suitably fastened between upper crossbars I9I and I82 and having a substantially inverted V-shape, may extend for the purpose of centering and gripping the bars to be twisted, to locate the latter in cooperative relation to twisting heads 53, 5|, and 52 during a certain operative period of the machine.

Fig. 4 shows the lifting mechanism in its closed and elevated position. When pressure fluid is admitted to port I65 of cylinder I63, piston I88 with piston rod I61 and links I69 will move to the left, and the fluid on the left-hand side of piston I66 will be returned to tank through port I64. Bell crank I10 will be rotated in counterclockwise direction, thereby rotating the doubleended rocker arms I15 and I16 also in counterclockwise direction. In consequence, connecting rods I19 and I80, carrying the lower cross-bar I40 with trough-like lifting members I4I, I42, and I43, will be lowered, and connecting rods III and I82, actuating cross-bars I9I and I92 with centering members I44, I45, and I46, will be raised. This position of the lifting or centering mechanism is illustrated in the view to the left of the center line of Fig. 5 and also inFig. 3.

n the other hand, when pressure fluid is admitted to port I64, when piston I66 is in its extreme left position, the piston will be urged towards the right, and the liquid in the cylinder on the right-hand side of piston I66 will be returned to tank through port I65. Bell crank I10 and rocker arms I15 and I16 will be rotated in clockwise direction, thereby lifting connecting rods I19 and I80 with cross-bars I40 and lifting members I, I42, and I43. Simultaneously therewith, connecting rods I8I and I82 will be lowered, thereby lowering cross-bars HI and I92 with centering members I44, I45, and I46. As a result, the ends of the bars to be twisted will be raised and simultaneously centered and clamped in pockets, such as I48, formed between the upper centering members, such as I44, and the lower lifting members, such as I4I. This raised and closed position of the centering device is shown most clearly in the view to the right of the center line in Fig. 5. The vertical and horizontal axes of pocket I48 coincide exactly with the respective center lines of their corresponding twisting heads. Consequently, when said twisting heads are moved into their clamping position at a certain predetermined point in the automatic sequence of operations, they will find the ends of the bars properly aligned for clamping.

Counter A counting mechanism I95, operating in the conventional manner to count revolutions of the rotatable twisting heads 53, 5I, and 52, is carried on bracket I96, fastened to the side of headstock 2I (Fig. 4). Counter I95, shown in greater detail in Figs. 9 and 10, derives its drive from an endless sprocket chain I98, passing over driving nected with shaft 200 by coupling means 204, or

the like. A reset shaft 205 on the opposite side of the counter I95, adapted to reset said counter to zero, is similarly connected by coupling 205, or the like, with shaft 201, having a pinion 208 out integral with it and being mounted in suitable bearings 209 and 2I0 of bracket I96. Rackended piston rod 245, slidably mounted at right angles to shaft 201 in a suitable bore of boss 2I I, forming part of bracket I96, is in mesh with pinion 208 and depends from piston 2I3, slidable in cylinder 2I2, which is bolted or otherwise fastened to the back of bracket I96 (Fig. 10). Said cylinder 2I2 has left and right-hand pressure ports 2I4 and 2I5, and its back cover 2I9 is provided with set-screw 2I1, lock nut 2I8, and acorn nut 2I9.

Counter I95 embodies a one-way clutch (not shown in Figs. 9 and 10) for reset shaft 205, adapted to effect resetting only when reset shaft 205 is rotated in clockwise direction, as viewed in Fig. 10. It will be understood that counter I is adapted to open an electric circuit after a predetermined number of revolutions has been recorded. It will close said electric circuit only when the counter has been reset to zero for arresting the twisting operation, as will be more fully explained hereinafter.

When directing pressure fluid into port 2I4, piston 2I3 will be urged to the right. The hydraulic fluid to the right of said piston 2I3 will be returned to tank through port 2I5, and rackended piston rod 245 will rotatepinion 208 in clockwise direction until the counter is reset to zero (Fig. 10). The length of stroke of piston 2I3 toward the right is precisely limitable by adjustment of set-screw 2I1, which is of great practical importance, because failure to reset the counter exactly to zero would result in interrupting the sequence of operations of the automatic cycle for the reason to be more fully explained hereinafter. When pressure fluid is admitted to port 2I5, with piston 2I3 in its extreme right position, said piston 2I3 will be urged towards the left, and rack 245 will rotate pinion 208 in counter-clockwise direction. However, as previously pointed out, a one-way clutch, provided in counter I95 in connection with reset shaft 205, will prevent any counter-clockwise rotation of pinion 208 and shaft 205, respectively, from influencing its setting.

Electric circuit As shown in Fig. 11, wires 222 and 223 constitute a power line and return or ground line, respectively, for the several electric motors and controls. Power line 222 includes a manual main switch 224 and a normally closed, spring-returned manual switch 242. At a point between said switches 224 and 242, a wire 221 is connected with power wire 222 and, by means of its branch wires 228 and 229, supplies current to one terminal of electric pump motors 225 and 226, respectively. The other terminals of motors 225 and 226 are connected by means of branch wires 23I and 232, respectively, with wire 230, which forms a part of ground line 223.

A three-wire, spring-returned push-buttontype switch 249, whose upper and middle sets of contacts are normally open, and whose lower set of contacts is normally closed, has one of its upper contacts connected with power line 222 by a wire 250. A wire 25I, including a contactor coil 252, connects its other upper contact to one of its middle contacts, and a wire 241 connects the other middle contact to the lower left-hand terminal of two-wire, spring-returned limit switch I39, Whose upper left-hand terminal is shown connected by a wire 248 with said wire 25I. The two lower contacts of switch 249 are connected by wires 253 and 243 with wire 25I and with the lower right-hand terminal 244 of limit switch I39, respectively. Upper right-hand terminal 246 of said switch I39 is connected with one side of a solenoid-operated, four-way valve 259 by means of a wire 260. A wire 26I, which leads from the other side of said valve 259 to ground wire 223, completes this electric circuit. A wire 251, with normally open contactors 256 interposed therein, connects power line 222 with wire 25I between switch 249 and contactor coil 252, the latter being adapted to close said contactors 256 when electric current is flow- 248, while the one between wires 243 and 260 is open.

A wire 254 is connected with wire 241 and leads to one terminal of conveyor motor I2I and its magnetic, spring-loaded brake 258. A wire 255 connects the other terminal of said motor I2I with ground wire 230, completing this circuit. One terminal of a normally open pressure-reactive switch 281 is connected by means of a wire 214, including a contactor coil 69, with wire 260, while a wire 298 leads from its other terminal to one side of a solenoid-operated, four-way valve 291, whose other side is connected by wire 3I8 with ground wire 230 to complete the circuit. A wire I41, including a set of normally open contactors 83, is connected at one end with wire 214 between coil 69 and switch 281 and at its other end with wire 288. As long as current flows in wire 214 and, hence, through coil 69, the latter will keep contaotors 83 closed. Thus, an electric circuit will be established, which by-passes switch 291. Its purpose will appear more fully hereinafter.

A normally open pressure-reactive switch 261 is connected by wire 269 with power line 222 and by wire 210 with one terminal of the switch in counter I95, said switch being closed only when counter I95 is reset to zero. Wire 2" leads from the other terminal of said switch in counter I95 to lower left binding post 212 of a two-wire pressure-reactive switch 213, which is adapted to hold the circuit normally closed between its upper contacts 216 and 211 and to hold the circuit normally open between lower contacts 212 and 219. A wire 304 connects contact 218 with one terminal of twisting motor 25 and its magnetic springloaded brake 40. A wire 233 leads from the other terminal of said motor 25 to ground wire 230, thus completing this particular circuit. A manually operated switch 305 is interposed in line 304 and also connected by wires 3I1 and 3I6 with power line 221 and ground 230, respectively. Said switch, illustrated diagrammatically in greater detail in Fig. 12, normally holds the electric circuit closed in wire 304, coming from pressure switch 213 and leading to motor 25, and normally holds the circuit open between wires 3I1 and 3I6.

At a certain period of the cycle of operations, to be more fully explained hereinafter, and while no current is flowing in wire 304, it may be desirable to reverse twisting motor 25 by reversal of its field 306 by means of switch 305 (Fig. 12). Said switch 305 comprises six sets of contacts, whose upper three are normally closed and whose lower three sets are normally open. The top set of contacts normally holds the circuit closed in wire 304, coming from the pressure switch 213 and continuing to one terminal of twisting motor 25. A wire 229 connects the fourth set of contacts from the top with the power line 3I1 and continues to the same terminal of the motor, the circuit being normally open in this line. The second set of contacts from the top connects line 304 with one side of field 306, this contact being normally closed. The sixth set of contacts from the top connects the ground wire 230 with the same side of field 306 as the second set of contacts by means of wire 3l8, this contact being normally open. The third set of contacts from the top connects the ground wire 230 with the other side of field 308, this contact being normally closed, and the fifth set oi contacts from the top connects the power line 3I1 with said other side of field 306, this contact being normally open. It will be seen that, when spring-returned switch 305 is actuated, after counter I96 has interrupted the electric circuit to 2H and 304, the three upper sets of contacts will all be opened, while the three lower ones will be closed. Consequently, the electric field and the direction of rotation of motor 25 will be reversed.

The second circuit through switch 213 is constituted by a wire 215, connecting terminal 216 of said switch 213 with wire 214 at a point in advance of coil 69, and a wire 219, connecting terminal 211 with one side of solenoid-operated, four-way valve 280, whose other side is connected with ground wire 230, completing the circult.

A normally open limit switch 295 is connected with power wire 222 at a point beyond switch 242 by a wire 296 and with one side of solenoidoperated, four-way valve 298 by a wire 291; the electric circuit is completed by wire 3I9 leading from the other side of solenoid-operated, fourway valve 298 to ground wire 230.

Hydraulic circuit Suction pipes 236 and 231 of pumps 234 and 235, respectively, communicate with the respective interiors of reservoirs or tanks 99 and I21, which may contain any suitable pressure fluid. Through outlet pressure ports 238 and 239, respectively, the pressure fluid is forced into respective main conduits 240 and 24I (Fig. 11). It will be understood that electric main switch 224 is usually closed and electric motors 225 and 224 and their respective pumps 234 and 235 are constantly in operation when the machine is in use, so that pressure is provided in said main conduits 240 and 2.

Inlet port 262 of spring-loaded, solenoid-operated, four-way valve 259 is connected to conduit 240, and, in its normal, de-energized position, said valve 259 will direct the pressure fluid from said inlet port 262 to upper port 301, connected by pipe 308 and suitable branch pipes to the front ports 98 of stationary clamping cylinders 96, whose rear ports 91, in turn, communicate through branch pipes 265 with a conduit 264, which terminates in lower port 263 of said valve 259. In said de-energized position of valve 259, the hydraulic fluid on the left side of pistons will be under negligible pressure only and is free to ilow from said lower port 263 to an outlet port communicating with discharge pipe 309, Open to the interior of tank 99.

When solenoid-operated valve 259 is energized, its valve spool will be lifted against spring pressure. and fluid pressure will be directed from inlet port 262 to lower port 263 and through conduit 264 and branch pipes 265 to the rear ports 91 of stationary clamping cylinders 96. Pistons 95 will thus be urged towards the right and expel the fluid in cylinders 96 to the right of said pistons 95 through cylinder ports 98, conduit 308, valve port 301, and outlet port and discharge pipe 309 back to tank at negligible pressure.

Said valve 289 and all other solenoid-operated, four-way valves, such as designated by numerals 288, 29I, and 298, used elsewhere in the circuit, are of standard and well-known design and similar to the type shown in Fig. 6 of my U. S. Patent No. 2,217,301.

Normally open pressure-reactive switch 261, including a drain pipe 268 communicating with the interior of tank 99, is connected by pipe 268 with conduit 264 and will close the electric circuit between wires 269 and 218 when a predetermined maximum hydraulic pressure has been reached in conduit 264 after the Jaws 64" in stationary clamping heads 86, 81, and 88 have gripped the bars to be twisted with the desired force equivalent to said predetermined maximum hydraulic pressure. At a lower pressure, or when valve 289 is tie-energized and the fluid pressure irn conduits 284 and 266 is of a nominal magnitude only, pressure switch 261 will be in open position.

Another spring-loaded, solenoid-operated, tour-way valve 288, similar to previously described valve 259 and having its inlet port 28I connected to main conduit 24I, is arranged'for controlling piston or plunger I66 in cylinder I63 of the lifting and centering mechanism 23. An upper port 285 and lower port 282 of said valve 288 are con- .nected by pipes 284 and 283, respectively, to the respective rear port I65 and front port I84 of cylinder I63. An outlet or discharge port of valve 288 communicates by means of pipe 286 with the interior of tank I21. In its normal, de-energized position, said solenoid-operated valve 288 will direct the pressure fluid from inlet port 28I to upper port 285 and through pipe 284 to cylinder port I65. Hydraulic fluid to the left of piston I66 is free to return to tank at nominal pressure through cylinder port I64, pipe 283, lower port 282, and outlet port and pipe 286.

When energized, valve 288 will direct the pressure fluid which enters inlet port 28! to lower port 282 and through conduit 283 to front cylinder port I64. Hydraulic fluid to the right of piston I88 is free to return to tank I21 at negligible pressure through rear cylinder port I65, conduit 284, upper port 285, and discharge port and pipe 288.

Conduit 283 is also in communication, by means of a branch pipe 298, with a normally open pressure-responsive switch 281, which includes a drain pipe 289 open to tank I21, and which is similar in every respect to switch 261, previously described. Said switch 281 will close the electric circuit between wires 214 and 288 when a predetermined maximum pressure has been built up in conduit 283 after lifting and centering the bars to be twisted. At a lower hydraulic pressure, or when solenoid-operated, four-way valve 288 is de-energized and conduit 283 is open to tank at nominal pressure, as previously set forth, switch 281 will return to its normally open position.

Still another spring-loaded, solenoid-operated, four-way valve 29I, similar in every respect to the ones previously described, is adapted to control the movement of indexing piston 31 with its piston rod 38 to shift sub-base 26 and, hence, twisting heads 53, I, and 52 into working position. Four-way valve 29I has its inlet port 292 connected to main conduit 24I its discharge port open to tank I21 by means of pipe 3I5, and its lower and upper ports 293 and 3 I 4 in communication, respectively, with rear port 32 and front port 33 of indexing cylinder 34 by means of respective pipes 294 and 36. In the normal, de-

energized position of said solenoid-operated valve 29I, pressure fluid from conduit 2 is in communication with front port 38 of indexing cylinder 34 through inlet port 292, upper port 3I4, and conduit 36; fluid under nominal pressure is free to return to tank I21 through rear port 32, conduit 294, lower port 293, and discharge port and pipe 3I5. When the solenoid of said valve 29I is energized and lifts the valve spool against spring pressure, pressure fluid from conduit 2 is in communication with rear port 32 of indexing cylinder 34 through inlet port 292, lower port 293, and conduit 294. Fluid to the left of piston 31 is free to return to tank I21 at nominal pressure through front port 33, conduit 36, upper port 3 and discharge port and pipe 3I5.

A further spring-loaded, solenoid-operated, four-way valve 298, similar in action and design to valves 259, 288, and 29I,.already described, and having its inlet port 299 also connected with main conduit 2, is arranged to control the operation of clamping pistons 18, reset'piston 2 I3, and a pressure-reactive switch 213 including drain pipe I58. In its normal, de-energized position, valve 298 is adapted to direct the pressure from inlet port 299 to an upper port 3I8, which is in communication with front ports 11 of rotatable clamping cylinders H by means of a pipe 3. Simultaneously, pressure will also be directed by a pipe 3I3, branching oil conduit 3I I, to the rear port 2I5 of reset cylinder 2I2, moving piston 2 I3 forward. The resulting anti-clockwise rotation of pinion 288 will leave the setting of counter I undisturbed, because a one-way clutch 228, shown diagrammatically in Fig. 11, will prevent transmission of said anti-clockwise rotation to the counting mechanism, as previously explained.

' The fluid to the right of pistons 18 is free to return to tank I21 at negligible pressure through rear cylinder ports 18, a pipe 38I connecting said ports 18 with a lower port 388 of valve 298, and discharge port and pipe 3I2. Fluid in front of piston 2I3 will be returned to tank I 21 through front port 2I4 and a pipe 882, which forms a branch of conduit 38I.

When solenoid-operated valve 298 is energized, its valve spool will direct the pressure from inlet port 299 to lower port 388 and by means of pipe 38l to rear ports 18 of rotatable clamping cylinders 1| to close the laws in twisting heads 5I, 52, and 53. Simultaneously therewith, fluid under pressure will flow through branch pipe 382 to front port 2I4 of cylinder 2I2, thus resetting counter I95 to zero by the action of rack 245 and causing the electric'circuit in counter I95 to be closed between wires 218 and 21I. Two-wire, pressure-reactive switch 213 is also connected by pipe 383 to main conduit 38I; hence, when a predetermined maximum pressure has been built up in conduit 38I, after the jaws 64 and 64' in twisting heads 5I, 52, and 53 have been set on the bars to be twisted, the normally closed electric circuit between wires 215 and 219 will be opened, and the normally open electric circuit between wires 21I and 384 will be closed.

Operating cycle After completion of one complete operating cycle, the parts occupy the positions illustrated diagrammatically in Fig. 11. The three bars twisted in the preceding cycle have been released by the stationary clamping heads 86, 81, and 88, as well as by the twisting heads 53, SI, and 52 and have dropped again into their respective pockets in carrier links I32 aligned with said heads of the twisting station. Jaws 64 and 64' in rotatable heads 5i, 52, and 53, and laws 64" in stationary heads 86, 81, and 88 are open, as shown in solid lines in Figs. 6 and 8, respectively. The headstock 2I, mounted on sub-base 26, has been shifted into its extreme right-hand position. The solenoid-operated, four- way valves 258, 288, "I, and 298 are de-energized, and pressure- reactive switches 281, 281, and 213 are in their normal positions. The lifting and centering device 23 is in inoperative position, as depicted in Fig. 3; counter I95 still shows the number of twists recorded during the preceding operating cycle, and its switch, therefore, holds the electric circuit open, but, contrary to Fig. 11, main switch 224 will be closed, thus keeping electric motors 225 and 226 with their respective hydraulic pumps 234 and 235 in constant operation. The conveyors 24 are at rest, having been stopped by cam I38 on sprocket wheel I34, actuating limit switch I39, and thereby interrupting the electric circuit to electric motor l2i at a predetermined point in the preceding operating cycle. Contactors 256 and 83 are open.

To begin a new operative cycle of the machine, three bars are loaded into the aligned loading pockets, a, b, and c (Fig. 3) of the several transverse and spaced-apart conveying or feeding means 24 (Figs. 1 and 2) with intermediate portions of said bars spanning the space between adjacent conveyors 24, and opposite end portions of said three bars projecting beyond the centering means 23 and conveyor 24 adjacent to tailstock 22, respectively. The left-hand end portions project somewhat into horizontal recesses 98 of stationary clamps 86, 81, and 88. When the bars have thus been placed, the manual, spring-returned switch 249 is momentarily actuated, thus opening the electric circuit between wires 253 and 243, and closing the electric circuit to start conveyor motor I2I by directing the current from power line 222 through wires 258, 25I, 241, and 254. Coil 252 simultaneously closes contactors 256, thereby establishing another electric circuit, independent of and by-passing switch 249, between said power line 222 and wire 25I as long as current is flowing in said wire 25I and coil 252. Simultaneously with actuating switch 249, motor I2I, and, consequently, conveyors 24 will start to operate. Cam I38 on sprocket wheel I34 will free arm 22I of springreturned limit switch I39, thereby opening the circuit between wires 243 and 268 and closing the circuit between wires 241 and 248. After releasing the only momentarily actuated switch 249, conveyor motor I2I wil continue to operate, because it receives electric current from power line 222 over by-pass circuit 251, wires 25I, 248, 241, and 254, and, although the circuit is now closed between wires 253 and 243, no current will flow in wire 268, since the circuit is now interrupted between terminals 244 and 246 of limit switch I39.

The upper runs of the endless chains forming parts of conveyors 24 move toward the left in Fig. 3, carrying the bars twisted in the previous cycle from the twisting station to the left or unloading side of the machine and conveying the untwisted bars in loading pockets (1, b, and c from the receiving position, shown in Fig. 3, to predetermined positions at the twisting station, so as to be in axial alignment with the stationary clamps 86, 81, and 88 and in longitudinal alignment with twisting heads 53, 5i, and 52, respectively. In this position of the conveyors 24, cam I21 on sprocket wheel I34 will actuate lever valve 29L 16 HI of limit switch r39. thereby opening the electric circuit between vres 248 and 241 and stop ping conveyor moto- I2I. At the same time, the circuit will be closed between wires 243 and 288, and solenoid-operated, four-way valve 258 will be energized, thus moving pistons to the right and closing gripper jaws 84" in stationary clamps 86, 81, and 88 with a predetermined force over the left-end portions of the bars to be twisted. Pressure switch 261 will respond thereto and close the electric circuit between wires 269 and 218. As this takes place, solenoid-operated, four-way valve 288 will also be energized, since electric current will also flow in wires 214, 215, and 219. As previously explained, this will result in moving piston I66 of lifting and centering device 22 towards the right, thereby lifting, centering, and holding the other ends of said bars to be twisted in axial alignment with twisting heads 53, 5i, and 52, respectively, as shown to the right of the vertical center line in Fig. 5. At a predetermined pressure in conduit 283, pressure switch 281 will close the electric circuit between wires 214 and 288, thereby energizing solenoid-operated, four-way Electric current flowing in wire 214 will cause coil 69 to close contactors 83, thus establishing by means of wire I41 an electric circuit which by-passes switch 281. Energizing solenoid-operated valve 291 will result in moving piston 31, and, hence, sub-base 26 to the left, to locate the open jaws 64 and 64' of twisting heads 53, 5|, and 52 over the right-end portions of said bars or workpieces to be twisted, as shown in Figs. 2 and 4. Towards the end of its travel, subbase 26 will contact and actuate limit switch 295 and close the electric circuit between wires 296 and 291 for energizing solenoid-operated, fourway valve 298. This will cause clamping pistons 18 to move to the left, thereby closing jaws 64 and 64 of twisting heads 53, 5i, and 52 (as shown in dotted lines in Fig. 6) over the respective right-end portions of the work-pieces to be twisted. The bars to be twisted are now clamped at both their ends and with their right hand ends in the twisting heads at a higher level than the adjacent conveyor pockets. The bars will, therefore, be suspended in the air during the twisting operation to follow, because the bars are usually under tension stresses during the twisting operation, since they are prevented from following their natural tendency to shorten. Simultaneously with the clamping of the right-end portions of the work-pieces, reset piston 2I3 will move to the rear and will reset counter I95 to zero, causing the electric circuit between wires 218 and 21I to be closed. At a preset hydraulic pressure, switch 213 will respond and open the electric circuit between wires 215 and 219 and close the electric circuit between wires 2H and 384. Therefore, solenoid-operated valve 288 will be deenergized, piston I66 will be caused to return to its original position, shown in Fig. 11, and, hence, return lifting and centering device 23 into initial, inoperative position (Fig. 3), thereby freeing the bars or stock for the twisting operation to follow. The hydraulic pressure in conduits 283 and 298 being now negligible only, pressure switch 281 will open the electric circuit between wires 214 and 288, but the electric circuit to valve 29I will not be interrupted, because the current will still flow through the by-pass wire I41, whose contactors 83 are closed at this point of the cycle. The aforementioned closing of the electric circuit between wires 21I and 384 will result coincidentally in starting twisting motor 25 to ro- 17 tate twisting heads 58, and 52 for helically twisting the stock.

Pressure switch 281, counter l85, and pressure switch 213 are in series. Hence, twisting motor 25 can start only when the respective electric circuits in all these devices are closed, indicating that the preceding operations have taken place in the manner intended; otherwise, the automatic sequence of operations will be interrupted at this point, and possible damage to the equipment or an unsatisfactory product will be prevented. Should the automatic cycle be interrupted, or should it become desirable to interrupt the same, all parts of the machine may be actuated to return to their respective initial positions by actuating manual switch 242, without first finishing the remainder of the cycle.

Normally, the twisting operation is continued until the bars have been subjected to a predetermined number of twists, for which the counter I95 is set. At this point, counter I85 will act to open the circuit in which it is located and thereby cause the twisting motor 25 to be stopped, which represents the final step of the automatic cycle made possible with the control arrangement shown in Fig. 11.

When the twisting operation has been completed, the twisted bars, because of inherent forces, tend to untwist or uncoil. To take this so-called spring-back out of the bars, twisting motor 25 and, hence, twisting heads SI, 52, and 53 may be reversed at this point by means of manually-operated switch 305. After recoiling the twisted bars a few turns, to eliminate the spring-back and neutralize the inherent forces developed in the bars during the twisting operation, switch 385 is released and reset-switch 282 actuated, which results in opening the electric circuit beyond said switch 242. As a consequence, solenoid-operated, four-way valves 259, 298, and 291 willbe de-energized and their valve spools returned by spring pressure into their initial positions, thereby opening the jaws of stationary clamps 88, 81, and 88 and those of twisting heads 53, 5i, and 52, as well as shifting sub-base 28 into initial position. Pressure switches 251 and 218 will return into their normal positions, and contactors 256 and 83 will also open as soon as the flow of the electric current is interrupted by actuating switch 242. The twisted bars are, consequently, released and will drop into their respective pockets of conveyors 24, preparatory to the next cycle of operation of the machine.

The machine combines relative mechanical simplicity with maximum efliciency, because the several operations of the automatic cycle, despite their complexity, follow one another in natural sequence, requiring for their timing and control only simple and, therefore, reliable, inexpensive control devices. The hydraulic actuation of the gripping jaws permits the applicationof heavy pressure to cause the jaws to bite into the bars, eliminating slippage between bars and jaws during the twisting operation and thereby insuring a uniform product. The wedge-shaped, selfenergizing jaw-holders tend to tighten the jaws on the bars as the axial pull of the latter increases as a result of the stretching thereof, which generally accompanies their helical twisting.

It should be noted that for the shifting of headstock 2i into-clamping position, for actuating its twisting heads 5|, 52; and 53 to clamp the workpieces at one end, for actuating the clamping heads 85, 8 1, and 8,8 of tailstock 22 to clamp the opposite ends'of said work-pieces, and for actuating the centering device, all of which units com- 18 prise a twisting station, hydraulic means are employed. While an electric motor has been proposed for rotating twisting heads 51, 52, and 58, it will be understood that hydraulic means may be employed instead, if desired.

While in the embodiment of my invention, as disclosed, the automatic cycle of operations comes to an end after the twisting motor 25 has been stopped, uncoiling of the twisted bars and resetting of the several devices into their original posi tion may also be incorporated into the automatic cycle, if desired, by employing means analogous to those disclosed in my.aforementioned U. S. Patent No. 2,217,301, without departing from the spirit of the present invention. I have shown and described, by way of example, mechanisms as well as hydraulic and electrical controls for obtaining the stated objects, but it will be obvious to those skilled in the art that my invention is not limited thereto but is susceptible to various changes and modifications in the specific forms shown and described.

The electric wiring diagram has been shown intentionally in the simplest possible form, to facilitate tracing of the various circuits which are opened and closed during the working cycle. The multiple automatic twisting machine has been depicted, by way of example, as adapted to twist three bars simultaneously; but it may be modified to twist one bar alone or any desired number of bars simultaneously. The twisted bars are designed primarily foruse as concrete reinforcements, although they are not limited to such use, nor is the machine restricted to the production of such reinforcement bars and may be employed for twisting stock of any suitable composition, including plastic material.

The pressure- responsive switches 251 and 215 are in series with counter I as a check on the preceding operations. It is obvious that pressure switch 261 could be altogether eliminated, if so desired, and wire 210 directly taken from the power line 222 without changing the natural sequence of operations as described.

While centering means are shown only for loeating the ends of the bars adjacent to the twisting heads 5|, 52, and'53, similar means may be employed for locating the opposite ends of the bars adjacent to the clamping heads 85, 81, and 88.

It is obviously not essential that the rotatable twisting heads'5l, 52, and 53 are located at a higher level than clamping heads 85, 81, and 88. Their respective levels might be reversed; or both might be located at an identical but higher level than the bottoms of loading pockets 0., b, and c, in which case lifting and centering means may preferably be used at both ends of the rods or work-pieces.

I desire, therefore, that only such limitations shall be placed on the scope of the present invention as are specifically set forth in the appended claims.

What I claim is:

1. In a machine for automatically twisting stock in a successive series of operations of the machine, means for receiving and conveying-the stock to a predetermined position at a twisting station, clamping means for engaging one end of the stock at said station, other means at said station adapted to grip the respective opposite 'end of said stock, hydraulic actuators for said control' clamping and said gripping means, means for said hydraulic actuators, means to rotate said grippermeans to twist said stock at said station, means to then reverse actuation of said gripper means to partially uncoil said twisted 19 stock, and to free the stock from said clamping and gripper means preparatory to the next cycle of operations of said machine.

2. In a machine for automatically twisting a plurality of work-pieces simultaneously in a successive series of operations of the machine, means for receiving and conveying a plurality of workpieces to predetermined positions at a twisting station, clamping means for engaging one end of the work-pieces at said station, other means at said station adapted to grip the opposite ends of said work-pieces, hydraulic actuating means and electrically actuated control means for said clamping and said gripping means, means to rotate said gripper means to twist all of said workpieces simultaneously at said station, and means ing means, gripping means, and locating means being hydraulically actuated and electrically controlled, means to then rotate said gripper means 1 counting means to zero prior to the twisting opfor automatically arresting the twisting opera- 1 tion when the work-pieces have been subjected to a predetermined number of twists.

3. In a machine for automatically twisting a plurality of bars simultaneously in a successive series of operations of the machine, means for receiving and conveying a plurality of bars to predetermined positions at a twisting station, clamping means for engaging one end of the bars at said station,othermeans atsaid stationadapted to grip the opposite ends of said bars aligned in said .sta-

tion, hydraulic actuators for said clamping means and for said gripping means, hydraulic controls for said hydraulic actuators, said hydraulic controls being electrically operated, means to then rotate said bar gripper means to twist all of said bars simultaneously at said station, means for automatically arresting the twisting operation when the bars have been subjected to a predetermined number of twists; and means to then reverse actuation of said gripper means to partially unc'oil said twisted bars-and to free the bars from said clamping and gripper means preparatory to the next cycle of operations of said machine.

4. In a machine for automatically twisting a plurality of work-pieces simultaneously in a successive series of operations of the machine, electrically controlled and actuated means for receiveration, means to reverse rotation of said gripper means to partially uncoil said twisted work-pieces, and means to release the work-pieces from said clamping and gripp r means preparatory to the next cycle of operations of said machine.

6. In a machine for automatically twisting a plurality of bars simultaneously in a successive series of operations oi the machine, a main frame, electrically controlled and actuated means for receiving and conveying a plurality of bars to predetermined positions at a twisting station, clampinglmeans for engaging one end of the bars at that station, said clamping means being hydraulically actuated and electrically controlled, meam to anchor said clamping means selectively at different spaced-apart points along said frame to accommodate varying lengths of bars, other means at said station adapted to be shifted into ing and conveying a plurality of work-pieces to predetermined positions at a twisting station, clamping means for engaging one end of the work-pieces at said station, other means at said station adapted to grip the opposite ends of said work-pieces aligned in said station, hydraulic actuators for said clamping means and said gripping means, electrically operated hydraulic control means for said hydraulic actuators, means to then rotate said gripper means to twist all of said work-pieces simultaneously at said station, counting means for automatically arresting the twisting operation when the bars have been subjected to a predetermined number of twists, and adjustable plunger means to reset said counting means to zero just prior to the twisting operation.

5. In a machine for automatically twisting a plurality of work-pieces simultaneously in a sucper means have gripped said ends, said clampgripping podtion preparatory to ripping the opposite ends of said bars, said shiitable gripping means being in longitudinal alignment with the first clamping means, electrically controlled hydraulic actuating means for shifting said gripping means into working position in response to said first-mentioned clamping .means, centering means for locating said opposite ends of the bars into axial alignment with said gripping means, electrically controlled hydraulic means for actuating said gripping means to then grip said opposite ends 01' the bars, means to return said centering means to initial position in response to the 81199 8 operation, means to then rotate said gripper means relative to said first clamping means to helically twist all of said bars simultaneously at said station, a counting device for automatically arresting .the twisting operation when the bars have been subjected to a predetermined number of twists, plunger means to reset said counting device to zero,-.means to reverse rotation of said gripping means to partially uncoil said twisted bars, and means to release the bars from said clamping and gripping means preparatory to the'next cycle of operations of said machine. A

7. In a machine for automatically twisting a plurality 01' bars simultaneously in a successive series of operations oi. the machine, a main frame, electrically controlled and actuated means for receiving and conveying a plurality of bars to predetermined positions at a twisting station, clamping means mounted on said frame for engaging one end of the bars at said station, electrically controlled and hydraulically actuated means for actuating said clamping meansin response to the conveying operation, twisting means mounted on said frame in longitudinal alignment with the level or the first clamping means adapted to be shifted into grippi position preparatory to grip ping the opposite ends of said bars, electrically controlled and hydraulically actuated centering means also responsive to said conveying operation. for locating and opposite ends of the bars into ean-r position, further electrically controlled and hydraulically operated means for then actuating said twisting means to grip said opposite ends of the bars, electrically controlled and hydraulically actuated means for returning said centering means into initial position in response to the gripping operation of said twisting means, means to then rotate said twisting means relative to.said first clamping means to helically twist all of said bars simultaneously at that station, a counting device operatively connected to said twisting means for automatically arresting the twisting operation when the bars have been subjected to a predetermined number of twists, adjustable means to reset said counting device to zero, means to reverse rotation of said twisting means to partially uncoll said twisted bars, and means to release the bars from said clamping and twisting means preparatory to the next cycle of operations of said machine.

8. In an automatic machine of the character described, a clamping unit for engaging one end of a work-piece, a gripping and twisting unit for engaging the opposite end of said work-piece and for helically twisting said work-piece, a centering unit for aligning said opposite end of the workpiece with said gripping and twisting unit, in combination with means to automatically cause the actuation of all of said units or parts thereof in a predetermined successive series of operations.

9. In an automatic machine of the character described, in combination, rotatable means, power means operatively connected with said rotatable means for their actuation, a counting device adapted to automatically arrest said rotation after a predetermined number of revolutions, plungeractuated means for automatically resetting said counting device to zero preparatory to the next cycle of rotation, and adjusting means to accurately limit the resetting stroke of said plunger.

10. In an automatic machine of the character described, means for receiving and conveying a plurality of work-pieces to predetermined positions at a twisting station, a clamping unit for engaging one end of said work-pieces, a gripping and twisting unit for engaging the opposite ends of said work-pieces and for helically twisting said work-pieces, a centering unit for aligning said opposite ends of the work-pieces with said gripping and twisting unit, and electrically controlled hydraulic means to automatically cause the actuation of all of said units or parts thereof in a predetermined successive series of operations.

11. In an automatic machine of the character described, means for receiving and conveying a .plurality of bars to predetermined working positions at a twisting station, a clamping unit for engaging one end of said bars, a gripping and twisting unit for engaging the opposite ends of said bars and for helically twisting said bars, said conveying means being adapted to position one end of the bars in the horizontal working plane of said clamping unit and to position the opposite ends of the bars in a lower horizontal plane than said gripping and twisting unit, a lifting and centering unit for aligning said opposite ends of the bars with said gripping and twisting unit, and hydraulic means to automatically cause the actuation of all of said units or parts thereof in a predetermined successive series of operations.

12. In an automatic machine of the character. described, electrically controlled and actuated means for receiving and conveying a plurality of bars to predetermined working positions at a twisting station, a clamping unit for engaging one end of the bars, a gripping and twisting unit for engaging the opposite ends of said bars and for helically twisting said bars, the working plane of said gripping and twisting unit being above that of that clamping unit, a lifting and centering unit for lifting said opposite ends of said bars to the working plane of said gripping and twisting unit and to locate said bars in axial alignment thereto, and electrically controlled hydraulic means for actuating all of said units or parts thereof in a predetermined successive series of operations.

13. In an automatic machine of the character described, means for receiving and conveying a plurality of work-pieces to predetermined working positions at a twisting station, a clamping unit for engaging one end of said work-pieces, a centering unit for aligning said ends of the workpieces in clamping relation to said clamping unit, a gripping and twisting unit for engaging the opposite ends of the work-pieces and for helically twisting the latter, another centering unit for aligning said opposite ends of the work-pieces with said gripping and twisting unit, and fluidpressure means for automatically actuatin all of said units or parts thereof in a predetermined successive series of operations.

14. In a machine of the character described, means forreceiving and conveying a plurality of bars to predetermined working positions at a twisting station, a clamping unit for engaging one end of said bars, a gripping and twisting unit for engaging the opposite ends of said bars and for helically twisting said bars, a centering unit for aligning said opposite ends of the bars with said gripping and twisting unit, in combination with means for automatically actuating all of said units or parts thereof in a predetermined successive series of operations.

15. In a machine for automatically twisting a plurality of bars simultaneously in a successive series of operations of the machine, a main frame, electrically controlled and actuated means for receiving and conveyin a plurality of bars to predetermined positions at a twisting station, stationary clamping means mounted on said frame for clamping one end of the bars at said station,

electrically controlled and hydraulically actuatedmeans for actuating said stationary clamping means in response to the conveying operation to clamp one end of the bars. twisting means mounted on said frame in longitudinal alignment with said clamping means and adapted to be shifted into gripping position preparatory to gripping the opposite ends of said bars, the working plane of said twisting means being above that of said clamping means, electrically controlled and hydraulically actuated centering means for lifting said opposite ends of the bars into gripping alignment with said twisting means also responsive to said conveying operation, other electrically controlled and hydraulically actuated means responsive to said centering operation to shift said twisting means into gripping position, further electrically controlled and hydraulically operated means responsive to the shifting operation for actuating said twisting means to grip said opposite ends of the bars, additional electrically controlled and hydraulically actuated means responsive to the gripping operation for returning said centerin means into inoperative position, means to then rotate said twisting means relative to said first clamping means to helically twist all of said bars simultaneously at that station, a counting device operatively connected to said twisting means for automatically arresting the some 23 twisting operation when the bars have been subjected to a predetermined number of twists, hydraulically controlled and actuated means to reset said counting device to zero coincidentally with said gripping operation, manually controlled means to reverse rotation of said twisting means to partially uncoil said twisted bars, and other manually controlled means to release the bars from said clamping and twisting means and to return all parts of said twisting station to their respective initial positions preparatory to the next cycle of operations of said machine.

16. In a machine for automatically twisting a plurality of bars simultaneously in a successive series of operations, a main frame, electrically controlled and actuated means for receiving and conveying a plurality of bars to predetermined positions at a twisting station, stationary clamping means mounted on said frame for clamping one end of the bars at that station, electrically and hydraulically controlled but hydraulically actuated means for actuating said stationary clamping means in response to the conveying operation to clamp one end of the bars, rotatable clamping means mounted on said frame in a different plane than said first stationary clamping means but in longitudinal alignment therewith, said rotatable clamping means being adapted to be shifted into gripping position preparatory to gripping the opposite ends of said bars, centerin means for locating said opposite ends of the bars in gripping alignment with said rotatable clamping means, electrically and hydraulically controlled but hydraulically actuated means for operating said centering means in response to the trolled but hydraulically actuated means respon sive to the shifting operation for actuating said rotatable clamping means to grip said opposite ends of the bars, auxiliary electrically and hydraulically controlled buthydraulically actuated means for returning said centering means into inoperative position in response to the gripping operation,

means also responsive to said gripping operation to then rotate said rotatable clamping means relative to said stationary clamping means to helically twist all of said bars simultaneously at that sta-- tion, a counting device operatively connected to" said rotatable clamping means for automatically arresting the twisting operation when the bars have been subjected to a predetermined number of twists, means also responsive to said gripping operation to reset said counting device to zero prior to the twisting operation, manually con trolled means to reverse rotation of said rotatable clamping means to partially uncoil said twisted bars, and other manually controlled means to release the bars from said stationary and said rotatable clamping means and to return all parts of said twisting station into their respective initial positions preparatory to the next cycle of opera-' tions of said machine.

ODD WENNBERG.

REFERENCES CITED The following references are of record in the:

file of this patent:

UNITED STATES PATENTS

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