US2723702A - Process for the production of colddeformed rods of the kind used for reinforcing concrete - Google Patents

Description

E. WYSS Nov. 15, 1955 2,723,702 PROCESS FOR THE PRODUCTION OF COLD-BEFORMED RODS OF THE KIND USED FOR REINFORCING CONCRETE 7 Sheets-Sheet 1 Filed NOV. 27, 1951 Nov. 15, 1955 5 2,723,702

E. WYS PROCESS FOR THE PRODUCTION OF COLD-DEFORMED RODS OF THE KIND USED FOR REINFORCING CONCRETE Filed Nov. 2'7. 1951 7 Sheets-Sheet 2 Nov. 15. 1955 E. wYss 2,723,702

PROCESS FOR THE PRODUCTION OF COLD-DEFORMED RODS OF THE KIND USED FOR REINFORCING CONCRETE Filed Nov. 27, 1951 7 Sheets-Sheet 3 Nov. 15, 1955 E. wYss 2,723,702

PROCESS FOR THE PRODUCTION OF COLD-DEFORMED RODS OF THE KIND USED FOR REINFORCING CONCRETE Flled Nov 27 1951 7 Sheets-Sheet 4 NOV. 15, 1955 wYss 2,723,702

PROCESS FOR THE PRODUCTION OF COLD-DEFORMED RODS OF THE KIND USED FOR REINFORCING CONCRETE Filed Nov. 27, 1951 7 Sheets-Sheet 5 Nov. 15. 1955 E. WYSS 2,723,702

PROCESS FOR THE PRODUCTION OF COLD-DEFORMED RODS OF THE KIND USED FOR REINFORCING CONCRETE Filed Nov. 27, 1951 7 Sheets-Sheet 6 Nov. 15. 1955 E. wYss 2,723,702

PROCESS FOR THE PRODUCTION OF COLD-BEFORMED RODS OF THE KIND USED FOR REINFORCING CONCRETE United States Patent PROCESS FOR THE PRODUCTION OF COLD- DEFORMED RODS OF THE KIND USED FOR REINFORCING CONCRETE Eugen Wyss, Zurich, Switzerland, assiguor to Walter Huguenin, Tesserete, Tessin, Switzerland Application November 27, 1951, Serial No. 258,336

Claims. (Cl. 153-78) The invention relates to a twisting process for elevating the yield point of, in particular, concrete reinforcing steel under conditions of minimum loss of elongation, and to a machine for carrying the said process out economically.

The known twisting processes are based on the principle that the workpiece is clamped at both ends in a twisting machine by clamping-heads or jaws. During the twisting process, either both clamping heads are stationary, or one of the jaws may be arranged for longitudinal displacement. As a result of the torsional and tensile stress a change in the molecular crystal grid is achieved which results in a raising of the yield point and tensile strength at the cost of a reduction in the elongation values of the starting material. Rods which are cold-twisted heat up, from which fact it is deduced that internal friction occurs. Internal friction can be reduced by vibration, for which reason the rods should be vibrated during the twisting operation. A cold-twisted bar becomes weakly magnetic, for which reason the possibility is afforded of influencing the cold-forming work effected by torsion, by an electromagnetic field.

Drawn and annealed material would be best suited to the process of cold-twisting. Unfortunately, however, the cost of such material is too high. In general rolled material is employed, which is not uniform in cross-section. The thinner the cross-section is, the greater are the differences between minimum and maximum cross-section which occur within a rolled rod from metre to metre of its length.

The rolled material is not, in practice, annealed, instead, it is allowed to cool down on a cooling bed. Depending on the heat-conductivity of the bed, and the localized influence of cold air-currents, the rod cools in a very irregular manner. The result of this is a corresponding lack of uniformity in its mechanical properties, particularly marked variations in the yield point being observed when a rod is tested section by section. These variations may be considerably more than 1 kilogram per square millimetre. These two sources of faults may offset one another, but they may also be cumulative. In the latter case, and particularly when the fault is located in the vicinity of the driving clamping-head, the torsional stress may lead to local over-stressing of the twisted cross-section. Such cases lead to rejects the more frequently, the greater are the production lengths of the workpieces and the greater are, in consequence, the internal frictional forces to be overcome. Since it is desired to achieve a specific minimum yield point throughout the length of the rod, the cold-forming process must be adapted to the lowest yield point occurring in the original material. The number of turns is therefore always too high if determined in relation to the average yield point of the workpiece. Excessively high numbers of turns cause too great a drop in elongation, and the longer the workpiece is, the more considerable is the loss of elongation. Since, in the processes described above, a rod which is clamped at both ends must, after being twisted, be unclamped at both ends and the next rod clamped in the now vacant clamping-heads, there results a standby period for the machine which can be reduced in an extremely unsatisfactory manner only by increasing the operating speed on the one hand and by using the longest possible rods on the other hand. An abrupt onset of the cold-forming process is equivalent to a sudden stress, which should be particularly avoided in the case of Thomas-steel. Methods in which the motor drive was arranged midway along rods of double the commercial length led to an inacceptable decline in elongation owing to the increase of internal friction.

According to the invention, the aforementioned difiiculties are practically eliminated, since the workpiece to be twisted is no longer grasped at the two ends. In the method according to the invention part only of the workpiece is twisted, whilst the following, as yet untwisted section is continuously or intermittently fed forward by pulling or pushing. For this purpose the two clamping arrangements between which the cold-forming process takes place are provided with bores going right through. The rotating and stationary clamping devices are both axially displaceable, and are of such design that they can slide along over the twisted intermediate section so as to draw along a subsequent, as yet untwisted section (assuming the machine to operate on the tractive principle, which is advisable in the intermittent section-by-section twisting of soft material having a high yield point). The continuous tractive method is suitable when workpieces of relatively high yield point are to be twisted, so as to give the workpiece a helical form whilst moderately raising this yield point. In this way it is possible to meet to a very large extent the demands of the concrete engineer in respect of increasing the adhesion of reinforcing rods. This method is recommended in certain cases inthe manufacture of twin steel when, in stationary plants, the wear on the mechanical equipment is to be reduced to a minimum and cheap material of circular cross-section and suitable yield point is available. When twisting separate rods, the continuous tractive method is also possible, but is suitably only for the twisting of rod material having practically no yield point range. As soon as workpieces having a yield point range are involved, difiiculties arise. At the first clamping device, which applies the distorting torque to the rod, the frictional forces are without consequence, but at the second clamping member, which has to operate in the opposite direction of rotation, the frictional forces assume undesirable proportions during the twisting operation and the tractive feed of the work. The extra expenditure of tractive energy is economically not justified. Twisting section-by-section, i. e. intermittently, by the tractive method as explained below in describing the operative cycle of the twisting machine according to the invention is advantageous in regard of reliability, power requirements and space requirements of the machine plant.

Continuous pusher-feed is also possible according to the invention with workpieces which have no yield point range. Otherwise, it must be borne in mind that the entire yield point range must be overcome in order to attain the predetermined yield point. Now, thrusting or compressive force operates in an opposite sense to torsional force. The deformation of the material is subject to the so called Bauschinger effect and is accordingly unfavourably affected.

Although the continuous processes described in the foregoing, which may be effected by either tractive or pusher feed, are also an object of the present invention, I shall restrict myself, in describing the working cycle, to the intermittent section-by-section tractive twisting method, as this method readily and satifactorily permits of the Widest application to the most highly diversified grades of work materials. The workpiece is twisted between the two clamping-heads, which are provided with bores going right through. According to the invention, the workpieces are no longer clamped at the two ends. The Workpiece is inserted through the opened, second clampinghead into the first clamping-head located a short distance away therefrom, so that one end can be gripped by the first clamping-head as soon as the said first clamping-head automatically closes when the machine is in operation. The two clamping-heads move backwards and forwards whilst maintaining a constant distance between them, and whilst closed, twist a section of the workpiece, and automatically slide along over the twisted section of the workpiece so as automatically to seize the next section and twist it similarly to the first, and so on, until the entire workpiece has been twisted. In this way, during the deforming process, that number of turns only which is required for the short length (in practice less than one metre) of the section can act on the latter, whereby the internal frictional forces in the workpiece are limited to the short section, and the possibility of local overstressing with its consequence of an undesirably heavy loss in elongation is reduced to the lowest practical minimum. The second clamping-head which counteracts the first rotary twisting head, travels with the same axially during the twisting process, as otherwise, owing to the torsional effect, the tractive feed would require undesirable additional power.

Since the process according to the invention operates with the same number of turns and with a constant working stroke of the working cylinder per rod cross-section when twisting by the intermittent tractive method, the mechanical equipment required can be limited to the length of the twisting and feeding mechanism. Independently of this, the equipment for bringing up the untwisted workpiece end-on, and for the removal of the twisted workpieces from the ejector side, are set up separately, as convenient, and according to the desired length of workpiece.

The processes according to the embodiments of invention specifically described hereinafter offer the following advantages over the methods hitherto known:

(1) By restricting the cold-forming process to sections of the workpiece, the amount of internal friction to be overcome is reduced. As a result, the longation decreases less and at a given minimum yield-point the elongation of the twisted rod is several percent higher than it would have been had the rod been twisted from both ends.

(2) As a result of the limitation of the internal friction to sections of the rod, the deformation at the ends, of the rod is scarcely any higher in degree than that of the intermediate portions of the workpiece. Since as a rule the ends of the rods have to be bent into hooks and thereby undergo additional cold-forming, the danger of fracture of the hooks is practically avoided.

(3) Faults in the material, such as slag occlusions, or macroscopic faults, which are inevitable in hot-rolled material, become manifest during the cold-forming process, provided the fault in respect of cross-section is greater than is commensurate with safety. However, whereas, in processes in which the rods are gripped at both ends, entire rods or groups of rods are lost as scrap, the wastage with the method according to the invention is limited to the faulty section of the workpiece.

(4) Since the workpiece undergoes the twisting process in successive sections, the consecutive workpieces can, during the cold-forming of the sections, be welded together at their ends to form a continuous workpiece.

(5) Since the workpiece is never subjected to cold-working from both ends, but only in sections, it is possible to introduce the leading section of the following workpiece into the mechanism, of the machine whilst production is proceeding.

(6) The machine according to the invention preferably has individual drive, by an electric motor, transmission shafting, internal combustion engine, compressed air, bydraulic, or by any other means.

The development of concrete building practice leads to the use of rods of ever smaller cross-sections. The resultant reduction in Weight per running metre reduces the necessary power of the individual twisting-head. The individual drive and the great reduction in the dimensions of the machines according to the invention as compared with the stationary twisting machines hitherto used make it possible to assemble groups of machines which meet the requirements arising in practice. If it is borne in mind that for ordinary concrete reinforcing steel the most customary dimension is 10 mm. diameter, and that for cold-worked steels every higher stresses and correspondingly smaller diameters are used, those machines only which are capable of efiiciently cold-working crosssections of 0.2 cm. to below 0.5 cm. can be economically satisfactory. Since the cross-sectional area increases by the square law, the capacity in the small dimensions is decisive. For instance, for the production of 10,000 kilograms of Caron steel of 9 cm. 71 rods (bars) 20 metres long are required for 10,000 kilograms of (Iaron steel of 0.2 cm. 3165 bars 20 metres long are necessary. The time required for clamping up such a large number of workpieces calls for groups of machines with many clampingheads. According to the invention it is possible for one man to serve 35 clamping-heads, with an idling loss for the machine of 2 to 4 seconds per Caron rod of 0.2 crn. an output which, to the best of may knowledge, is not even nearly approached by the known systems.

Every production plant must be capable of cold-twisting both the heavy and light profiles; machine groups comprising at least one heavy and a plurality of light clamping-heads are always required. A division into heavy and light machine groups has proved expedient in practice. With these individual-drive machines manufactured in series, any desired groupings can be formed according to the required production. The dimensions of the separate machines are so limited and so small that groups of Caron steel for the production of 10 tons per day of any desired dimensions from 0.2 to 9 cm. crosssectional area can be loaded on one lorry. The production plant is no longer, as hitherto, tied to one site, instead, bar-twisting installations can be temporarily set up in store yards and on large building sites.

in accordance with the invention, workpieces of any desired length can be produced on the standard machine without adjustment of the machine, since operation is on the basis of a constant working stroke of the cylinder and a, constant number of turns per cross-section of bar.

Assembled groups, moreover, can simultaneously twist the most varied profiles, since for each profile the appropriate twisting-head is speedily fitted to a suitable standard machine by means of a bayonet joint.

In order to keep the cost of the standard machine low, importance was attached to robust design and the use of materials of the highest grade, whilst on the other hand the use of delicate machine components such as gears and gearwhecls was avoided. In accordance with this principle, all the working parts of the machine, which was developed as an automatic unit, were made to operate by mechanical control. It would also be possible, however, to build the machine semi-automatic or with operating, members of other design without thereby dcparting from the idea of the present invention. In the same way, all, or some, of the controls or operating members could be actuated electrically, magnetically, pneumatically, hydraulically or by some other means, instead of, mechanically, without departing from the idea of this invention.

Since, during the twisting operation, the yield-point range must be overcome and the. second power rise must be negotiated in order to ensure the attaining of the 5 minimum yield point aimed at, the mechanism is such that the clamping-members such as twisting-head, feed member and counteracting member enable the workpiece to deform in conformity with the characteristics of the material; the workpieces fairly distinctly show the individual phases of pre-stressing and final torsion.

The design of the machine attempts to combine, as far as possible, a plurality of mechanical movements in one machine component. For instance, the actuating cylinder is at the same time the support for the interchangeable profile twisting heads, and also for the most varied controlor operating-members. Mechanically speaking, the twisting-heads could equally well be driven separately and the cylinder could be built, for example, for axial movements only, without departing from the idea of the invention. Moreover, the twisting-head could be mounted stationary instead of rotatable, and the counteracting members made rotary, without departing from the idea of the invention.

The principle of the machine is a continuous tube system through which the workpiece is pulled or pushed. This arrangement also enables a suitable insert to be used between two individual rods when twisted in pairs. This enables the surfaces of the workpieces, and therefore their adhesion to the concrete, to be increased.

Since the workpiece is gripped at one end only and not at both ends, working from coils of wire is facilitated with the leading end of the wire introduced directly or, if necessary, roughly straightened, to enable it to be inserted into the machine, whilst the latterv is running.

As a sturdy and inexpensive method of drive, a chain drive by means of endless chains was selected, the said chain running over a lubricated friction cylinder and being tightened and slackened thereupon for the purpose of coupling and uncoupling, respectively. Instead of this system it would be possible to use a clutch and a rack and pinion, without thereby leaving the ambit of the invention. The same applies to the other structural parts which are of known design, but for which protection is sought on account of their expedient arrangement for the purpose of performing the process according to the invention. This refers in particular to the arrangement of the rotatably-mounted chain guide sprockets, actuating cylinder, recoil springs, control and actuating members of all kinds, tensioning or clamping devices, jaws, counteracting members and gripping arrangements, feed members, bearings of all kinds, etc., as specified in the following description of the operating cycle of the machine according to the invention.

The spring-actuation mentioned in the following description of an embodiment of the machine according to invention can, wherever feasible, equally wellbe replaced by weight-actuation or actuation by other structural elements.

Thus, in particular, the power of the spring, which is over-dimensioned in order to ensure an efficient recoil, can be wholly or partly utilized for tensioning the chains by being stored in a buffer spring. The drawback of this construction as compared with tensioning the chains by -means of weights is that dilferent springs would have to be used according to the weight of the steel section to be fed forward. Where weights are used, on the other hand, the variation of force requirement can be simply achieved by sliding the weight on a control lever. Operational hitches are much less probable here than where the recoil power is also used to feed the material forward, the weight of which varies according to the profile of the workpiece.

In describing the operating cycle, therefore, I restrict myself to an embodiment using weights.

In order' that the invention may be better understood and readily carried into etfect, three embodiments thereof will now be described with reference to the accompanying drawings, inwhich:

Fig. 1 shows a perspective view of the first embodiment} Figs. 6 and 7 show a modification of the embodiment of Figs. 1 to 4 including means for straightening the wires in plan view, in two different positions, Fig. 7 being a part view only.

Figs. 8 and 9 show a further embodiment of a device for straightening of wires drawn off from two reels, in elevation and in an enlarged section along the line 9-9, respectively.

Fig. 10 shows a torque head with a twisted and an untwisted portion of work piece in plan view,

Fig. 11 shows a torque head and part of the cylinder with chains wound on, in plan view,

Fig. 12 shows a twin-wire with insert in a perspective view on an enlarged scale,

Fig. 13 shows a torque head with operating mechanism in elevation,

Fig. 14 shows the torque head of Fig. 13 together with a counter member and diagrammatic linkage in elevation on a smaller scale,

Fig. 15 shows the jaws of the torque head on an enlarged scale in end view.

The motor 1 (Figs. 1 and 2) drives through belt pulleys 2 and 2a a shaft 58 on which two chain pinions 3 and 4 are arranged side by side. A link chain a and a link chain b are passed over the said pinions 3, 4, respectively and run in several turns, around a cylinder 5. The chains a and b are endless and are guided over return pulleys 8, 9 and 10 and tensioning pulleys 18, 19. The chains a and b He in helical coils around the cylinder 5 and are oiled, so that they can slide over the same when loose, or they can set the cylinder 5 into rotary movement and simultaneously into axial movement when tightened by means of the pulleys 18, 19. Guide rollers 6 and 7 have the purpose of ensuring that the chains a and b always coil themselves helically on the cylinder 5. The pulley 18 is journalled on a twoarmed lever 17, and the pulley 19 on a likewise twoarmed lever 17a, which levers are articulated to a threearmed lever 14 by means of the tie rods 15 and 16, respectively. On the arm 14a of the lever 14 a rod 13 is articulated, which is connected to the arm 12 of a bell crank lever. The other arm of this bell crank lever is denoted 20.

The cylinder 5 is bored, and is provided with a tubular extension 23. A collar 22 attached to the tube 22 can abut against an arm 24, which is tiltably pivoted on the machine frame and is connected by linkage 25 to a two-armed lever 21. Between a bearing 55 and a collar 29a, fixedly arranged on the tube 23, a compression spring 29 is provided.

With the cylinder 5 a torque head 32 (Figs. 2 and 4) is fixedly connected through an intermediate piece 32a, in which head the work pieces to be twisted can be held fast. The torque head 32 is axially shiftable relative to the cylinder 5. A similarly constructed torque head serves as a counter piece 38 which is likewise axially shiftable. On the latter a push rod 28 is attached, which cooperates with a pivoted pawl 27 biassed by a spring 27a, on the nose 27b of which pawl a lever arm 26 abuts which carries the weight 11 (Fig. 2). The lever 26 is tiltably pivoted in the bearing 12a and has a projection 26a. On the lever 26 the end of a tension member 30 is attached which is passed over a pulley 31 and is fixedly connected to an arm 32b of the intermediate piece 32a.

In the machine frame there is moreover pivoted a control lever 33, the outer end of which is connected to the intermediate piece 32a. The lever 33 is in connection with a feeder head 34 through linkage 35, 36, which feeder head is provided with a pawl 37 operating in one direction of movement only. i

The operation is as follows:

Firstly the motor 1 is switched on, whereby the chains a and b are set into motion. At the same time the work piece W (one or several wires) to be twisted is shifted from the left hand side (Figs. 1 and 2) through the counter piece 38 and the feeder head 34 right into the torque head 32. When the chains a and b are tightened, the cylinder 5 is set into rotary and at the same time axial motion by the motor 1. Simultaneously the torque head 32, intermediate piece 32a and, through the rod 39, also the counter piece 38 are moved to the right hand side. The arm 32]; carries along the roller 44, which is journalled on it, by means of the lever 43. This roller runs on to a plate 45 and effects through linkage 42, 41 the closing of the torque head 32. Thereby the work piece is immovably clamped fast. By the additional linkage 41a the work piece is at the same moment secured against turning in the counter piece 33. The rotating and axially moving cylinder 5 effects then twisting and an axial shifting of the work piece and of the components 32, 38. The Weight 11, which is in its lower end position, is raised by the tension member 36 until its lever 26 engages itself into the nose 27b of the pawl 27. However, the lever 20 still. abuts from below against a nose 21a of the lever 21, and thereby holds the chains a and I) under tension. When the cylinder 5 reaches its right hand side end position, in which the spring 2) is tensioned, the sleeve 22 abuts against the lever 24- and thereby is capable of tilting the lever 21 through the rod 25. At this moment the lever 20 is released, whereby the tensile action on the chains a and b through the linkage 12, 13, 14, 15, i6, 17, 17a and roller 18, 19 ceases. The chains slacken and the spring 29 expands. The cylinder 5, torque head 32 and counter piece 33 go to the left hand side into their initial position, while the feeder head 34 goes to the right hand side owing to the linkage 33, 35, 36. Thereby the pawl 37 carries the twisted portion of the work piece along, and pulls a subsequent, still untwisted portion after it.

As soon as the components 5, 32 and 38 have reached the extreme left hand side end position, the push rod 28 abuts on the pawl 27 and rocks the same against the action of the spring. 271:. The nose 27b slides olf the lever 26, and the weight 11 drops down. The projection 26a of the lever 26 presses the lever 20 down, whereby the levers 17, 170 are rocked through the linkage 12, 13, 14a, 4-1, and 16, and the chains are tightened again by means of the pulleys 13, 19. Consequently another working operation is started, which is analogous to the one described hereinabove. The lever 29 pressed down, is held by the aforesaid nose 21a of the lever 21.

in the aforesaid return movement of the torque head 32 obviously the head 32 as well as the counter piece 38 have been opened by means of the roller 44 and of the linkage 43, 42, 41, 41a.

The counter piece 38 serves for arresting the work piece, which is yet untwisted, for being twisted. This couter piece is constructed, analogous to the torque head, in such a manner that it can follow-up the differences in cross section of the work piece arising from the rolling tolerance. Since for each profile a certain magnitude of helical pitch is to be maintained in dependence of the degree of twist desired, and since the number of revolutions and the length of stroke of the working stroke cylinder are constant, a predetermined distance between the torque head 32 and the counter piece 33 results for each profile which has to be kept up; the rod 28 accordingly determines the helical pitch for a given profile. The movement of the counter piece 38 is directed in the same sense as that of the driving cylinder 5 and of the torque head 32, whereas the feeder member 34 moves axially in the opposite sense. By varying the length of the link 35 the distance between the torque head 32 and the counter piece 38 is regulated, and thereby the helical pitch desired is adjusted.

The end of the work piece itself controls the mechanism of the machine by releasing a feeler roller 47 arranged at the counter piece 38 after passing the funnel 40, which roller in turn drops in behind the end of the rod shaped work piece in front of the passage, now empty, and releases a lever 46. The lever 46 abuts against the pawl 48 owing to the axial reciprocating movement of the counter piece 38, after the dropping of the feeler roller 47, which pawl 48 in turn disengages itself at 49, whereby the ejector roller 50 lowers itself through the control linkage 51, 52, 53, 54 on to the twisted portion of the work piece, and ejects the finished, twisted work piece from the tube 23, owing to the counter roller 56 and the drive 57 from the driving shaft 58, whereby the next rod to be twisted can be introduced at the funnel 40, and whereby the working operation is repeated, and all this during full operation of the machine without setting the drive to a standstill.

The torque head 32 (Figs. 4 and 4a) the same as, besides, the counter piece 38, comprises for example three clamping jaws 132, each of which is suspended on a plate 134 by means of a link 133. When the plate 134 is pressed by the lever 41 against the stationary part 320 of the torque head 32, the jaws 132 are firmly pressed by the links 133 on the wire or wires or rods W to be clamped fast. When the pressure of the levers 41 on to the plate 134 ceases, the compression springs 135 open the jaws 132 at once.

The manner of operation as described with reference to Figs. 1 and 2 is such that in one operation stage firstly the wire or wires or rods are pulled along through one section and twisted, whereupon a further feed is effected. According to the length of the plate 45, the torque head 32 remains closed during a corresponding part of its path. By exchanging this plate the helical pitch can accordingly be adjusted in a simple manner for each cross section of the rods, although the torque head 32, the cylinder 5 and the feeder member 34 have always a constant number of revolutions. The feed is preferably so adjusted, that between the torque head 32 and the counter head 38 there remains a part section twisted. The magnitude of the feed can be varied by adjusting the link 35 on the rocker lever 33.

In contradistinction to the embodiment described hereinabove the torque head 32 and the counter piece 38 are arranged stationarily on the machine according to Fig. 5. 32 is again the rotating, 38 the non-rotating member. While according to Figs. 1 and 2 the torque head takes over part of the total axial shifting of the work piece, it is the feeder head 34, which according to Fig. 5 performs this task exclusively. The latter is attached to a beam 169 which is shiftable on the shafts 159, 160. Into this beam 169 a pawl 168 is engaged, which is tiltably pivoted on a slide 167. This slide is also shiftable on the shafts 159, 169, but it engages at the same time into the endless helical grooves 165, 166, respectively, thereof. When the shafts 159, are driven by the belt pulley 190, belt 191, pulley 181, tube 23, chain sprocket wheels 192, chains 164 and chain sprocket wheels 1651, 162, the slide 167 moves to the left hand side and carries along, by means of the pawl 168, the head 34 without the work piece. After having reached the end position, the pawl 168 abuts on a stop and thereby disengages itself from the rest 179. Then the beam 169 is quickly pulled to the right hand side by the action of springs 171, whereby the work piece W is fed forward another step. The slide 167, too, returns to the other end position owing to the grooves 165, 166, whereby the pawl 168 is automatically reengaged into the rest 170.

The opening and closing of the members 32 and 38 is elfected by means of a linkage 179, 178 and 177. The lever 177 has a hook 177a which engages a pin 180a of an arm 180. The latter is fixedly connected to a shaft 133 which is rotatable in bearings 176. On the said shaft 183 there are links attached which are under the action of cam discs 172, which receive their drive from shafts 159, 160 through bevel gearing 173, 174. The cam discs 172 accordingly control the opening and closing of the members 32 and 38 in the allotted periods. The drive of the torque head 32 is eifected from the motor 1 through the pulleys 190, 181 and belt 191, which drive the tube 23 as well as the head 32. The counter piece 38 and the torque head 32 are journalled in cross beams 194 of the machine frame. The ejector mechanism for the finished twisted wire is not represented; however, it may be constructed as shown in Fig. 2.

Instead of iron rods, as described hereinabove, wire, coiled on a reel, may alternatively be introduced into the machine, as illustrated in Figs. 6 and 7.

The iron (wire) 88 to be twisted runs off from coils 84 which are put on reels 85, between two parallel rails 86 and through a straightener 87. The two rails 86 let the bows of the wires pass with some clearance, but hold the same in a plane, so that they run in an orderly way to the straightener 87 and enter exactly at the level of the straightener rollers.

When a single wire only, e. g. one with a square profile, is to be twisted, a single reel 85 only is provided.

As shown in Figs. 6 and 7 the stroke beam 167 reciprocates at uniform speed between two extreme positions owing to the helical shafts 159 and 160. With this stroke beam 167, the straightener beam 89 is coupled by means of linkage 90, so that the straightener 87, which is fixedly connected to the beam 89, performs the same movements as the stroke beam 167.

In Fig. 6 the extreme right hand side end position of the stroke beam 167 and straightener 87 is represented i. e. the straightener 87 just starts moving towards the left hand side; the rollers of the straightener accordingly straighten the curved iron lying ahead of it along its path of stroke. From Fig. 6 it will further become clear that the pawls 91, owing to the abutments 92 which in the righthand end position of the member 89 moves the pawls 91 over a dead center, hold the straightener closed during its working stroke. A moment before, prior to the pawl 168 on the stroke beam 167 being disengaged from the pawl rest 170, so that the feeder beam 169 with the feeder mechanism can throw the untwisted iron into the opened torque head 32, the pawls 91 have opened the straightener i. e. under the action of the abutments 93 (see Fig. 7 so that the curvature of the still untwisted wires existing ahead of the straightener in its left hand side end position can pass the straightener without substantial friction at the aforesaid throwing-in movement. Only when arriving in its right hand side end position the straightener 87 closes again, owing to the abutments 92 and pawls 91, over the wires which are still straightened there, whereupon the process is repeated.

The reels 85 are coupled with one another by means of the crossed belt drive 94. One of the reels is set into motion by an electric motor and gearing in such a manner that the speed of feed of the wires corresponds to the speed at which the same are twisted. When starting the operation of the twisting machine, a wire reserve is to be made sure of, which corresponds to the twisting stroke, in order that the supply of the irons from the reels is not loaded.

In the device illustrated in Figs. 8 and 9 for the straightening of wires, the wires 88 to be twisted are again drawn off from the wire reels 84, and are guided between the rails 86 which are parallel to one another. Each wire forms an arc hugging the arcuate portion 60 ofa stationary counter piece 61 before being introduced into the funnel 40 of the counter head- 38. On a bracket 67 fixedly connected to the cylinder two rods 68 are articulated the other ends of which are connected each with a straightening member 62. Each one of the latter is tiltably suspended by means of links 69 and is provided with a convex forming face 63 the radius of curvature of which corresponds to that of the concave faces 60. It will be clear from the drawing, that any time the cylinder 5 moves to the left hand side the straightening members 62 which serve as percussion hammers are forced against the counter pieces 61 owing to their suspension. Each arc of wire hugging one of the concave faces 60 is thereby pressed by the straightening members 62 into the same and accordingly receives a curvature opposite to its former one. As soon as the cylinder 5 moves again towards the right hand side, the percussion hammers 62, too, move away from the wires. The wire sections lying within the concave faces 60 do not, however, spring back resiliently into their former position, but do so to such an extent only that they lie coaxial to the wire section within the counter head 38. Thereby a further wire section has been straightened which is to be twisted in the subsequent operation. Obviously each of the faces 68 must have such a curvature that in fact straightening of the wire arcs is achieved.

When a single rod of non-circular profile, or when several rods are to be twisted, in the counter head 38, a clear or slightly braking passage only can be provided instead of a clamp, as shown in Fig. 10.

In Fig. 11 it is shown that upon the running of every second link of a chain on to the roller 7, on the cylinder 5 and accordingly also on the work piece W a vibratory impulse is generated.

In order to increase the adhesive strength of pairs of rods in the concrete several means have been proposed. With the present machine there exists the possibility of twisting an intermediate layer 82 together with the rods, as shown in Fig. 12.

As well known, the rods are not always of equal thickness but deviate from one another slightly to the extent of the permissible rolling tolerances in diameter. These inequalities are preferably compensated thereby that the lever 41 is not attached rigidly but with a resilient member 99 interposed (Fig. 13).

Moreover, it is desirable to accommodate the closing movements of the gripping members 32, 38 which according to Figs. 1 and 2 are controlled by the linkage 41, 41a to the rolling tolerances to the same extent. This is effected according to Fig. 14 by interposing an intermediate lever 42a between the levers 41 and 42. The lever 42a is articulated to the lever 42 as well as to the linkage 41, 41a, and thereby ensures in any case the reliable closing of the two gripping members 32 and 38. The gripping jaws 132 (Fig. 15) have smooth cylindrical claming faces 132a which preferably are chamfered at 132b, whereby a funnel-shaped entry for the rods is formed.

While I have described hereinabove some typical and particularly useful embodiments of my said invention I wish it to be understood that I do not limit myself to the details and dimensions described and illustrated, for

obvious modifications will occur to a person skilled in' the art according to the conditions and circumstances in which my said invention is to be applied.

What I claim is:

1. In a machine for twisting cold-formed rods, particularly iron reinforcing rods for concrete, a frame, a torque head, means operatively connected with said torque head for rotating said torque head, a counter member nonrotatably mounted in said frame coaxially with said torque head, clamping means in said torque head for clamping a workpiece thereto, means associated with said torque head for operating said clamping means, means in said counter member for engagement with. said workpiece to prevent rotation of said workpiece in said counter member, feeding means movably mounted in said frame for intermittently advancing said workpiece in said counter member and torque head, means associated with said torque head and with said feeding means for actuating said clamping means and said feeding means in a predetermined timed relationship, and yieldable means associated with said torque head for yieldingly maintaining said torque head in its clamping position.

2. A machine as in claim 1, in which said feeding means is disposed between said torque head and said counter member.

3. A machine as in claim 1, including discharge means mounted in said frame for ejecting said workpiece therefrom, an actuating member for said discharge means mounted on said counter member and adapted to be operated when the workpiece leaves said counter member, and means interconnecting said discharge means and said actuating member to cause ejection of said workpiece.

4. A machine as in claim 1, including straightening means associated with said feeding means for straightening said workpiece prior to its entry into said counter member.

5. In a machine for twisting cold-formed rods, particularly iron reinforcing rods for concrete, a frame, a torque head, means operatively connected with said torque head for rotating said torque head, a counter member non-rotatably mounted in said frame coaxially with said torque head, clamping means in said torque head for clamping a workpiece thereto, means associated with said torque head for operating said clamping means, means in said counter member for engagement with said workpiece to prevent rotation of said workpiece in said counter member, feeding means movably mounted in said frame for intermittently advancing said workpiece in said counter member and torque head, means associated with said feeding means for adjusting the stroke of said feeding means, means associated with said torque head and with said feeding means for actuating said clamping means and said feeding means in a predetermined timed relationship, and yieldable means associated with said torque head for yieldingly maintaining said torque head in its clamping position.

6. In a machine for twisting cold-formed rods, particularly iron reinforcing rods for concrete, a frame, a torque head, means operatively connected with said torque head for rotating said torque head, a counter member non-rotatably mounted in said frame coaxialiy with said torque head, clamping means in said torque head for clamping a workpiece thereto, means in said counter member for engagement with said workpiece to prevent rotation of said workpiece in said counter member, feed ing means movably mounted in said frame for intermittently advancing said workpiece in said counter member and torque head, means associated with said feeding means for adjusting the stroke of said feeding means, gripping means in said feeding means for clamping said feeding means to said workpiece during the advancing stroke of said feeding means, means associated with said feeding means for releasing said gripping means during the return stroke of said feeding means, means associated with said torque head and with said feeding means for actuating said clamping means and said feeding means in a predetermined timed relationship, and yieldable means associated with said torque head for yieldingly maintaining said torque head in its clamping position 7. In a machine for twisting cold-formed rods, particularly iron reinforcing rods for concrete, a frame, a torque head, means operatively connected with said torque head for intermittently rotating and reciprocating said torque head, a counter member non-rotatably mounted in said frame coaxially with said torque head, connecting means interconnecting said torque head and said counter member for reciprocating said counter member together with said torque head, clamping means in said torque head for clamping a workpiece thereto, means in said counter member for engagement with said workpiece to prevent rotation of said workpiece in said counter member, feeding means movably mounted in said frame for intermittently advancing said workpiece in said counter member and said torque head, means associated with said torque head and with said feeding means for actuating said clamping means and said feeding means in a predetermined timed relationship, and yieldable means associated with said connecting means for yieldingly maintaining said torque head in its clamping position.

8. In a machine for twisting cold-formed rods, particularly iron reinforcing rods for concrete, a frame, a torque head, means operatively connected with said torque head for intermittently rotating and reciprocating said torque head, a counter member non-rotatably mounted in said frame coaxially with said torque head, connecting means interconnecting said torque head and said counter member for reciprocating said counter member together with said torque head, clamping means in said torque head for clamping a workpiece thereto, means in said counter member for engagement with said workpiece to prevent rotation of said workpiece in said counter member, feeding means movably mounted in said frame for intermittently advancing said workpiece in said counter member and torque head, means associated with said feeding means for adjusting the stroke of said feeding means, means associated with said torque head and with said feeding means for actuating said clamping means and said feeding means in a predetermined timed relationship, and yieldable means associated with said connecting means for yieldingly maintaining said torque head in its clamping position.

9. In a machine for twisting cold-formed rods, particularly iron reinforcing rods for concrete, a frame, a torque head, a cylinder secured to said torque head coaxially therewith, a pair of endless chains arranged to be wound on said cylinder in a single layer, a series of pulleys over which said chains are mounted, driving means operatively connected with at least one of said pulleys so that rotation of said pulley causes rotation and axial advancement of said cylinder and torque head, release means for releasing said chains from engagement with said cylinder, actuating means connected with said cylinder for actuating said release means, a counter member non-rotatably mounted in said frame coaxially with said torque head, connecting means interconnecting said torque head and said counter member for reciprocating said counter member together with said torque head, clamping means in said torque head for clamping a workpiece thereto, means in said counter member for engagement with said workpiece to prevent rotation of said workpiece in said counter member, feeding means movably mounted in said frame for intermittently advancing said workpiece in said counter member and said torque head, means associated with said torque head and with said feeding means for actuating said clamping means and said feeding means in a predetermined timed relationship, and yieldable means associated with said connecting means for yieldingly maintaining said torque head in its clamping position.

10. A machine as in claim 9, including spring means associated with said cylinder to cause axial return movement of said cylinder and torque head upon actuation of said release means.

References Cited in the file of this patent UNITED STATES PATENTS 527,428 Kirchenbauer Oct. 16, 1894 1,500,936 Hoovens July 8, 1924 1,522,083 Stensrud Ian. 6, 1925 1,723,098 Ungerer Aug. 6, 1929 2,141,661 ONeil Dec. 27, 1938 2,216,758 Schmidt Oct. 8, 1940 2,487,972 Katz Nov. 15, 1949 FOREIGN PATENTS 453,445 Great Britain Sept. 11, 1936 463,939 Great Britain Apr. 8, 19-37

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