US3379385A - Machine for tensioning and winding wire onto pipe - Google Patents

Description

mmw MZ Aprxl 23, 1968 P. O'SWEILER MACHINE FOR TENSIONING AND WNDING WIRE ONTO PIPE Filed Sept. E,

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Unied States Patent O 3,379,385 MACHINE FOR TENSIONING AND WINDiNG WIRE GNT() PIPE Paul L. Osweiler, Dayton, Ghio, assignor to Price Brothers Company, Dayton, Ohio, a corporation of Michigan Filed Sept. 3, 1965, Ser. No. 484,936 3 Claims. (Cl. 242-11) ABSTRACT F THE DHSCLGSURE A machine for prestressing cable and winding it onto a concrete pipe by vertically supporting it on a shaft coaxial with a capstan and three element gear differential. A first motor reciprocates a wire distributing guide and rotates the pipe, shaft and planetary gears of said differential while a second motor rotates the sun gear of the differential at a speed regulated by a cable guide responsive to the tension and thus elongation of the cable. The cable is unwound from a supply, wrapped for several turns about the wire tensioning capstan connected to the ring gear of the differential, led over the tension responsive guide, then over the distribution guide to be connected to the pipe so that speed of rotation of the pipe is regulated to maintain constant tension in the cable.

This invention relates to means for winding tensioned strand over large pipe and particularly for working with heavy steel strand over large size pipe for prestressing. Pipes of steel or concrete or both having diameters as large as 12 feet and even more are reinforced by winding tensioned steel strand as a helix over such pipe. While the strand diameter and helix pitch may have a variety of values, depending upon the pipe design, a pipe length may have as much as 4 miles of strand and the strand size may be as great as about 3yrs-inch in diameter or transverse dimension. The strand tension during winding may be about 75% of ultimate and the pull on the strand may be in the order of about 15,00%` pounds.

Concomitantly with the creation of strand tension is strand elongation. With the steels used in this art and the tensions employed, strand elongation of about 1% results. Thus, strand elongation of between about 100 and 200 feet for a complete pipe length may be expected.

In addition to the above, the economics of pipe manufacture requires high speed handling of strand, as much as about i560 feet per minute, initiation of winding at either pipe end, temporary cessation of a winding operation without loss of tension, rapid adjustments to accommodate different pipe sizes, different strand sizes and tensions, different strand pitches and to do all these with minimum labor. Collateral to the above what may be termed operating economics, is the fixed investment factor of land or horizontal space required for conventional application of tensioned strand to pipe. Conventional tensioning means for taking up as much as 200 feet of added strand generally requires substantial horizontal space, the take-up in a vertical direction being too costly as a rule. Furthermore, such conventional tensioning and winding procedure and means are inherently inefficient and time-consuming.

The invention hereinafter set forth provides a means and method based upon a novel concept and makes it possible to operate efficiently at high speed and within a physical space which, in comparison to present apparatus and technique, is relatively small. The present invention utilizes a differential gear mechanism for strand elongation take-up. Substantially untensioned strand is fed to ICC a capstan, about which a number of strand turns is made for strand holding. From the capstan, the strand is guided to be wound under tension about the surface of a pipe to be reinforced. Strand tension is created by the operation of differential mechanism governing the relative speeds of rotation of capstan and pipe. Strand elongation take-up in such a system involves angularity instead of length as a variable parameter.

A differential gear mechanism basically involves three components; a sun gear, a ring gear and a planetary gear assembly (one or more gears and the arms or the like for supporting purposes). Positive power may be fed to one component, positive or negative (as braking) may be fed to another component and the third component can provide power. The power in each case involves angular velocity ratios (due to the meshing action of gears) and as a result makes it possible to obtain an overall differential operation which fulfills the needs of strand tensioning and winding as hereinbefore set forth. In the new system, positive power is supplied to two differential components and the selection of particular differential components for driving capstan and pipe respectively results in a system having decided advantages.

The new system includes introduction into the path of power flow of locking means to prevent potential energy stored in strand tension, during stoppage of winding, from backing up through the system and relieving the tension. Additionally, pitch control means are disposed in a power flow path to the pipe rotating means to maintain a desired ratio of pipe rotation and strand feed along the pipe.

An advantage of the system having two power inputs to the differential mechanism is that quick changes to accommodate differential pipe diameters, lengths, strand tensions rnay `be made. Furthermore, accurate tension control is obtainable in the new system utilizing a differential gear mechanism, apart from the number of power inputs. Thus, the new system has means responsive to tension of strand between the capstan and pipe for controlling differential action. Such a control is continuous and monitors the system to prevent substantial tension variations.

In the system illustrated here, the pipe being wound is coupled to the planetary gear assembly and the two have a main power input. A second and smaller power input is provided to the sun gear. The ring gear is coupled to the capstan. This coupling pattern makes possible a compact physical arrangement wherein the pipe and capstan can be yco-axial, turn in the same direction and strand feed and control are simplified. The internal forces oppose each other and reduce the overall power requirements.

The Imain power input to the pipe and planetary gear assembly takes care of power requirements for starting and winding generally. This main power input also functions to some degree to ten-sion the strand, much of the power input under running conditions being used for that. The ring gear, which is coupled to the capstan, receives power therefrom as the result of the strand drivin-g the capstan. The second power input to the sun gear is controlled by strand tension responsive means and provides `an over-riding force for strand tension control. This effect is obtained by controlling the relative peripheral speeds of strand leaving the capstan and going on to the pipe.

The second power input to the sun gear is through a one way power drive which permits power flow toward the sun -gear 4but prevents reverse power flow away from the sun gear. Thus, strand tension relief is prevented during stoppage of winding.

The physical larrangement of differential gear mechanism and associated capstan and pipe support is such that all parts rotate with or around a shaft which can be vertical and heavy enough to be stable `and well secured. The relative sizes of the two power input sources may vary widely. In general, the main power input to the pipe turntable and planetary gear assembly should be great enough, in comparison to the smaller power input to the sun gear, so that the action of the latter should have no substantial effect on the main power input insofar as pipe winding speed is concerned. Theoretically, the dierential coupling between the two power inputs may cause some instability due to feed back. In practice, the frictional resistance in the entire system, including the power sources land capstan drive, substantially eliminates instability due to coupling between power sources through the ditferential mechanism.

In order that the invention may be understood reference will now be vmade to the drawing illustrating a system embodying the invention.

Base has vertically disposed shaft 11 extending upwardly therefrom Iand rotatable therein. In practice the base will be a massive structure containing suitable bearings and heavy enough to support the various parts. Shaft 11 is of steel and may be solid or in the form of a heavy pipe. For ease of `assembly and transport to a location, shaft 11 may consist of a number of separate lengths suitably coupled together. It will therefore ybe understood that shaft 11 includes any extensions which may normally be required in a large structure of the general type disclosed herein.

Disposed about the lower portion of shaft 11 and rotatable with respect thereto is capstan 12 which may be dimensioned and shaped for handling the size strand used. In practice, capstan 12 may be one of two or three superposed capstans of various sizes rigidly secured together and having different diameters and faces for handling various pipe sizes. Capstan 12 accommodates a plurality of turns 14 of steel strand 15. Strand 15 comes from a suitable supply source having one or more reels and provided with suit-able means for imparting a llow initial tension to the strand to prevent reel unwinding and snarling. It is understood that strand portion 16 leaving capstan 12 will be under `desired tension for winding upon a pipe.

Capstan 12 is secured to `housing 20 extending upwardly from the capstan. Housing 2) has secured thereto ring igear 2]. at the upper interior portion. Meshing with the teeth of ring gear 21 are planetary `gears 23 rotatably supported in frame 24 which, in turn, is secured to rotate with shaft 11. Frame 24 lrnay have .as many planetary gears 23 as are necessary to carry the load.

Planetary `gears 23 also mesh with sun gear 26 which is rotatable about shaft 11. Sun gear 26 is rotatively secured to sprocket 27 so that rotary power may be fed to the sun gear. The ring gear, planetary gears and sun gear form a differential gear assembly.

Rotatively secured to shaft 11 is main drive sprocket 30 for receiving power to rotate shaft 11. Disposed above the top of shaft 11 and rotatively coupled thereto is turntable 33 for supporting a length of pipe 34 to be wound with tensioned strand. Turntable 33 would, in practice, be supported on heavy bearings and the entire turntable and pipe would be supported by heavy stationary framework independently of shaft 11. In addition, various parts of the ditferential would be provided with suitable bearings to reduce friction and support parts properly. Suitable means for lubrication will also be provided.

Turntable 33 is provided with centering blocks 36 which may be adjusted for various pipe sizes to enage and center the inside end of pipe 34. The top of pipe 34 is supported by hold down plate 38 which may be provided with centering blocks 39 generally similar to centering blocks 36. Hold down plate 38 is supported from cantilever arm 40 which is pivotally secured at 41 to slide block 42 supported for vertical adjustment on guideways of stationary vertical structure 43. Structure 43 can be adjusted to accommodate various lengths of pipe and be locked in position.

'Block 42 is provided with means for raising top plate 3S as shown in the dotted line position. Toggle arms 45 and 46 are pivoted respectively at 48 and 49 to arm 40 and block 42. The knee of the toggle is at pivot 50 and this is connected by rod 51. to a piston in air cylinder 52. To move top plate 38 clear of the top of pipe 34, cylinder 52 is energized to break the toggle and pull toggle pivot 5) toward block 42. Any other means for removing top cover 38 from the top end of pipe 34 may be provided. The removal of top plate 38 permits the removal from or positioning on, the turntable, as the case may be, of pipe 34. In addition, top plate 38 and the remainder of the structure for controlling the position of top plate 38 provides a retaining force for the top end of pipe 34 to maintain the pipe rigidly in position during winding.

Referring now to capstan 12, strand 16 leaving the capstan is guided to tension sheave 60 Whose axle pin forms part of clevis 61, which in turn is secured to a piston rod carried by piston 62. operating in air cylinder 62A. Air cylinder 62A is securely anchored to a stationary member and has air supply pipe 63 connected to the piston rod end of cylinder 62A andis connected through automatic air pressure control 63A to a suitable source of compressed air. The air pressure in cylinder 62A will determine the position of piston 62. and can thus, within limits, control strand tension. Air pressure control 63A can be set to maintain quite accurately the air pressure in cylinder 62A. This control will take care of momentary tension drops due to strand slippage on the capstan. Pipe 63 has pressure relief valve 63B to reduce momentary strand tension rises by permitting air from cylinder 62A to exhaust to the atmosphere when pressure rises. Pressure relief valve 63B can be used to disable the tension maintaining means and permit sheave 60 to move correspondingly.

The above arrangement for tension control is useful only for transient tension control. For continuous tension control and strand take-up, clevis 61 is coupled to potentiometer wiper 64 cooperating with resistor 65. The objective of the entire strand tension maintaining means is to obtain an electrical potential (or current) which is a function of the position of the piston in the cylinder and thus a function of the strand tension.

:Potentiometer resistor 65 is connected by wires to a suitable control means in a variable speed motor drive system generally indicated by 67. The drive system includes electric motor means and vvariable ratio transmission for obtaining a desired power output. Drive system 67 is connected through one-Way drive 63. One way drive 68 is of the type which will transmit rotary power to sprocket 69 but will not permit power to flow back from sprocket 69 to the motor drive system, irrespective of the direction of rotation. An example of a one-way drive device that can be used is a so-called R L Clutch manufactured and sold by Formsprag Company of Detroit, Mich. Such one-way drives are used in automotive vehicles to prevent road shock from being transferred back to the steering wheel, cutting tool machinery to keep a cutting tool in position against work, and elsewhere. Other devices, electrical, mechanical, or hydraulic may be used for obtaining the one-way drive action.

It is understood that the potentiometer control may be replaced by other tension responsive means for controlling variable motor drive 67. The one way coupling 68 is provided to maintain strand tension during work stoppage and prevent tension relief through the differential. Motor drive 67 will operate to take up excess strand length during winding and maintain a substantially constant strand tension during the take-up.

Returning now to strand 16 at sheave 60, the strand continues to guide sheave 70 which directs strand 16 vertically, parallel to but laterally offset .from the axis of pipe 34. Strand 16 goes from guide sheave 70 to payout sheave 72 from where the strand is fed to the outer surface of pipe 34. Payout sheave 72 has its axle 74 supported by arms 75 and 76 whose ends are pivotally secured at 77 and 78 respectively to form a trunnion. The trunnion axis is vertical, parallel to the axis of pipe 34 and in line with the line of vertical travel of portion 16A 0f the strand between sheave 70 and payout sheave 72.

The arrangement is such that payout sheave 72 can rotate about the trunnion axis and guide strand in a direction tangent to the outer surface of pipe cylinder 34, irrespective of the diameter of pipe cylinder 34. The trunnions for payout sheave 72 are supported by vertically movable carriage 79 which is guided for vertical travel along guideway 80 of vertical support structure 43. The vertical position of the trunnion carriage is controlled by chain 82 extending between sprockets 84 and 85 parallel to the pipe axis. The coupling between chain 82 and the trunnion carriage may be obtained in any suitable fashion by locking the two together. Chain 82 is supported to withstand the tension of strand portion 16A.

Main power source 90 consisting of an electric motor is used for driving sprocket 30 which is directly secured to shaft 11 for turning pipe 34. Motor 90 is coupled through variable speed transmission 91 to drive sprocket gear 92 which is connected to sprocket gear 30 by a suitable sprocket chain. Variable speed transmission 91 also drives sprocket gear 95 which is connected by a sprocket chain to sprocket gear 96. Sprocket gear 96 is connected through variable speed transmission 97 to one element 98 of clutch 99. Clutch 99 has selector portion 100 which may be selectively coupled to clutch element 98 or clutch element 101. Selector element 100 of clutch 99 is connected to drive bottom sprocket gear 85 which drives chain 82. Clutch element 101 is connected through gears and sprocket chain 103 to auxiliary motor 105.

The objective of the above arrangement for driving chain 82 is to obtain a desired chain speed in either direction while pipe 34 s rotating or to permit chain 82 to be driven independently of pipe 34 so that the carriage may be moved without necessarily having the pipe turntable and strand feed operating. As a rule, auxiliary motor S will be used for vertical carriage adjustment prior to strand tensioning. It is understood that auxiliary motor 105 can be controlled to drive the chain in either direction. Also variable speed transmission 91 in the power take olf from main motor drive 90 to sprocket gear 30 will permit the travel of chain 82 to be reversed, as for example when beginning to wind a pipe, so that the principal control for main drive motor will automatically operate the pitch control carriage in a desired direction and at a desired speed to obtain a desired strand pitch.

Limit switches may be provided for stopping the flow of power from main motor 90 to sprocket gear 30 when the pitch control carriage has reached a top or bottom limit position. Reversing switches may also be provided for reversing the direction of carriage travel after the carriage has reached a predetermined top or bottom strand winding position.

No attempt is made to show the relative magnitudes of main power drive motor 90, auxiliary motor 105 or variable speed differential motor drive 67. As a rule, main motor drive 90 should have a substantially greater amount of power available than variable speed motor 67. This is on the assumption that fast starting of strand winding and substantial winding speed, such as about 1500 feet of strand per minute are desired. Insofar as variable speed diflerential motor drive 67 is concerned the power required to provide suitable differential action for strand tensioning will depend in some degree upon the speed of winding. Thus in a practical machine for handling 3As-inch strand on pipe ranging up to 12 feet in diameter with a winding speed of about 1500 feet per minute, main motor drive 90 was 125 horsepower whle the motor drive for differential action 67 had a maximum rating of 50 horsepower.

It is undestood that the above figures represent maximum power ratings connected through suitable speed reduction means to accommodate different size strand on different size capstans for different size pipe. The direction of power feeds to the pipe and sun gear are arranged so that the pipe and capstan both turn in the same direction. When starting to wind a pipe the following procedure may be adopted. Assuming that the leading end of the strand is suitably anchored to the pipe, and before the main power drive for turning the pipe comes on to turn pipe 34, automatic air control 63A can be turned on to move sheave 60 and create tension in the strand. Then the drive for turning pipe 34 for strand winding can be started. When a pipe has been wound and the trailing strand end has -been anchored to the pipe, the main and differential power sources are disconnected from the loads (pipe 34 and sun gear 26) or arranged in a non-driving condition. Then the air pressure in cylinder 62A may be relieved to eliminate strand tension, after which the steel strand may be severed from the traling strand end on the pipe.

What is claimed is:

1. In a mechanism for winding tensioned steel strand in helical form about a cylindrical pipe of concrete or the like, a shaft, means for supporting said pipe coaxially with said shaft and coupled thereto for rotation therewith, a sun gear disposed over said shaft in coaxial relation therewith and rotatable with respect thereto, a spider frame over said shaft and coaxial therewith and coupled to rotate with said shaft, a plurality of planetary pinions supported on said spider frame for rotation about axes parallel to and laterally offset from the shaft axis, each planetary pinion meshing with said sun gear, a yring gear coaxial with said shaft disposed around and meshing with said planetary pinions to provide a planetary spur gear type of differential, a capstan secured to said ring gear, said capstan and ring gear being rotatable as a unit about said shaft, said capstan normally having plurality of strand turns therebout for developing strand tension during winding, a first idler for guiding tensioned strand to said pipe surface, means for mounting said first idler to be movable along a straight path parallel to but laterally offset from the pipe axis for providing winding pitch, means acting on strand extending between capstan and first idler to create predetermined strand tension, a lirst motor, means coupling said rst motor to said shaft at a region laterally offset from said differential to drive said shaft for pipe rotation to pull strand thereon, means for deriving power from said Afirst motor for moving said first idler mounting means, a second motor, means including a toothed member about said shaft coaxial therewith rigidly secured to said sun gear and laterally offset therefrom for coupling said second motor to drive said sun gear for rotating the same to take up added strand length due to tension and means responsive to said strand tension creating means for controlling the speed of said second motor to maintain said predetermined strand tension in connection with strand length take-up, said construction having the torques incident to differential operation contained within the differential gears and shaft with pipe and capstan rotating in the same direction for minimizing differential activity and having minimum number of gears, whose tooth dimensions may be easily proportioned to obtain proper loading without load distribution and gear teeth engagement problems, said construction being mechanically simple and readily susceptible for heavy duty high speed winding.

2. The mechanism according to claim 1 wherein a one way drive is disposed n the coupling between the second motor and the toothed member 0n the sun gear whereby when winding is interrupted, said strand tension reacts on the differential to keep the capstan and pipe from moving to reduce strand tension.

3. The mechanism according to claim 2 wherein the shaft is vertical with the pipe adjacent the top end of said shaft, the dilerential and capstan are below said pipe, and wherein the power couplings to said shaft and to said sun gear toothed member include sprocket chains extending laterally from the shaft axis, said arrangement permitting tensioned strand from the capstan tension strand 5 to the pipe and tensioned sprocket chains to extend transversely of the shaft in desired directions, the bottom shaft portion being available for good bearing support, said entire construction permitting minimium shaft length and not requiring precision vertical positioning of the dierm ential gear components for tooth engagement.

References Cited UNITED STATES PATENTS Bronander 74-675 Neugebauer 74-675 X Heinz 242--' 75.5

Kennison 242--11 Dutro et al 242-755 X Szulc 242-11 BILLY S. TAYLOR, Primary Examiner.

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