US 3147581 A
Description (OCR text may contain errors)
J. GODDVERIDGE 3,147,581
TWISTING FRAME ASSEMBLY Sept. 8, 1964 Filed May 6, 1965 Inven xror jean oc cjemidge Byflww, MM WM 14% fort ways United States Patent "cc 3,147,581 TWHSTING FRAME ASSEMBLY Jean Godderidge, 11 Blvd. Henri Barbusse, Honilles, France Filed May 6, 1963, Ser. No. 278,098 Claims priority, application France May 10, 1962 8 Claims. (Cl. 57-5863) This invention relates to apparatus for twisting ropelike elements, of the type used e.g. in the manufacture of double-twisted cables. Conventional twisting apparatus of this type generally comprises a twisting frame rotatable about an axis, and means for guiding the ropelike element to be twisted first from a point positioned on the axis of rotation radially outward of the frame, in a direction parallel to said axis across the frame, then radially inward of the frame back to said axis, and finally axially inward towards" a take-up means, such as a drum, rotatable about an axis transverse to the axis of frame rotation. When the frame is rotated about its axis and the take-up drum is simultaneously rotated about its transverse axis, the rope-like element, e.g. the strands of a cable, has twist imparted thereto, and the twisted element is taken up as a coil on the take-up drum.
Conventional twisting frames of this kind are open to the drawback that vibrations tend to be set up during high-speed rotation of the frame due to centrifugal forces acting on the relatively large revolving masses, coupled with the elasticity of the frame members. This has heretofore limited the twisting velocities that could be effectively attained, and hence the output rate of the finished twisted product. Objects of this invention are to reduce this tendency to vibrations and the objectionable effects of centrifugal force, and topermit a substantial increase in twisting velocity and production output.
According to an important aspect of the invention, there is provided a twisting frame comprising a pair of separate, generally symmetrical frame sections mounted in axiallyspaced relation for rotation about a common axis, take-up means, e.g. a drum, positioned between said frame sections and rotatable about a transverse axis, means for guiding a rope-like element to be twisted, from a point positioned on said axis outwardly of one of the frame sections, axially inward through said one frame section, radially outward to a point of said one frame section radially displaced from said axis, then axially across the intervening space between said frame sections to a correspondingly radially-displaced point of the other section, radially inward through said other section to a point on said axis, and then axially to said take-up means, means for rotating both frame sections in substantial synchronism to twist said rope-like element, and means for simultaneously rotating said take-up means to take up said element in its twisted condition.
As will be more apparent from the detailed description of an embodiment of the invention given hereinafter, the arrangement of the twisting frame in two structurally separate sections, separately though substantially synchro- 3,147,581 Patented Sept. 8, 1964 assembly can be safely rotated at speeds greatly exceeding those currently considered safe.
The accompanying drawing, given by way of illustration but not of limitation, is a side view, partly in axial section, of a twisting frame assembly according to an exemplary embodiment of the invention, with certain parts devoid of any direct bearing on the invention, including especially the drive means of the various devices rotated about transverse axes, being omitted for clarity.
The twister frame illustrated comprises a pair of aligned tubular shafts 1a and 1b mounted for rotation in bearings 2a and 2b respectively, which are supported from stationary frame means, not shown. The shafts 1a and 1b are driven in synchronous rotation from a common drive shaft 6, by way of identical belt drives including the pulleys 3a and 3b secured on the outer ends of shafts 1a and 1b, belts 4a and 4b and drive pulleys 5a and 5b secured on drive shaft 6. Shaft 6 is rotated from any suitable power source not shown. Secured transversely to the shafts 1a and 1b so as to define a common plane therewith are recessed crossmembers 7a and 7b respectively. Each cross-member has a pair of tubular arms secured to its outer ends and projecting therefrom towards the other cross member, the four arms being aligned in pairs. Thus cross member 7a carries the tubular arms 8a and 9a, and cross member 71) carries the respectively aligned arms 8b and 9b. It is obvious from the drawing that the ballooning of the rope or cable is inhibited to a considerable extent by the fact that the distance between the free ends of arms 8a and 8b is much smaller than the total distance between cross members 7a and 7b, the former distance being shown to be clearly less than onethird the latter distance. It can already be noted at this point that only one pair of aligned tubular arms i.e. 8a and 8b are effectively used while the other pair, 9a and 9b, are provided primarily for balancing purposes.
Means are provided in cross member 7a for guiding a rope or cable to be twisted, designated 12 and delivered into the recess of axial shaft 1a from the left hand end of the frame as indicated by an arrow, from the inner end of said recess in shaft 1a into the adjacent end of the tubular arm 8a. Said guiding means comprise a pair of pulleys 11a and Mia freely rotatable in the frame member 7a so as to guide the rope 12 over an S-shaped path as indicated. Correspondingly, a pair of guide pulleys 10b and 11b freely rotatable in the other cross member 7b serve to guide the rope from the far end of the guide tube 812 into the recess of the axial tube over a straight path so as to be thereafter fed back towards the centre of the frame as presently described.
Means are provided for improving the transit of the rope 12 over the gap between the spaced free ends of the guide arms 8a and 8b, said means generally designated 13a and 13b comprising as shown a pair of grooved rollers 16a and 16b freely rotatable on pins 15a and 15/) supported from the ends of brackets 14a and 14b projecting from the extremities of the guide arms.
A relatively stationary cradle 18 is supported in the central region between the two symmetrical frame sections described above, by way of being secured to the outer races of respective sturdy of antifriction bearings 17a and 17b, the inner races of which are secured around the inwardly directed ends of the axial shafts 1a and 1b. The suspended structure including cradle 18 and parts supported therefrom, presently described, is arranged so that its centre of gravity is well below the common axis of shafts 1a and 1b, so that it will not tend to be driven in rotation about said axis in the operation of the apparatus. Supported for rotation about a transverse axis by means of trunnions 22 on the centre of cradle 18 is a take-up drum 21. The cradle 18 supports near one end of it, on that side of drum 21 directed towards the output shaft 1b, a capstan or hauling device 19 of conventional type, comprising a pair of pulleys around which the rope 12 is adapted to be trained once or more times, one of the'pulleys constituting the capstan being driven in rotation through drive means not shown. .The rope 12 extending from the capstan 19 is passed in a direction parallel to the axis of the system across the drum 21 to a coiling device supported on cradle 18 at the opposite side from drum 21, whence the rope is deposited around the periphery of drum 21. The coiling device 20 is constructed so as to perform the conventional function of depositing the rope in orderly coils and in successive layers around the periphery of the drum 21. BRIEFLY, the device 20 comprises an arm 20a pivoted at one end on a longitudinal shaft 20b supported from the cradle 18, said arm being reciprocated in rocking movement about said shaft by means of a worm 20a rotatable about a transverse axis of the cradle and having a nut threaded thereon connected by way of a pinand-slot connection to the arm 20. The worm 20a may be formed with two crossed screw threads of opposite pitch so that when rotated from suitable means, not shown, it reciprocates the nut and therewith imparts a to-and-fro rocking movement to the arm 20a. A guide pulley 20d mounted for free rotation near the free upper end of arm 20a receives the rope 12 delivered to it by way of another guide pulley mounted near the base of the arm, and deposits the rope in orderly coils across the surface of drum 21 as the arm swings to and fro.
Take-up drum 21 is driven in rotation about its axis 22 through any suitable drive means, not shown, in timed relation with the rotation of the axial shafts 1a, 1b.
Balancing masses, shown at 230 and 23b, and at 24a and 24b, are provided at suitable points of the revolving frame structure described in that part thereof which does not receive the rope 12 therethrough, to ensure satisfactory dynamic balancing of the revolving assembly.
In operation, with the various parts driven in rotation as described above, the rope 12 is fed into the frame from the left hand end through shaft 1a, is passed by guide pulleys 11a and a to guide shaft Sal, at the outer end of which the rope is pressed by centrifugal force against an inner point of the periphery of roller 16a, bridges the gap between that roller and the aligned roller 16b Where it is similarly supported, enters the guide tube 8b, is passed therefrom over pulleys 10b and 11b into axial tube 1b and to the capstan 19, and then by Way of the coiler 259 to the take-up drum 21.
During high-speed rotation of the two sections of the twister frame the rope 12 is applied by centrifugal force against the radially outer areas of the inner surfaces of guide tubes 8a and 8b, and the tubes may advantageously be internally lined in that area with a removable strip of hardened and lapped steel to facilitate the sliding of the rope and reduce wear. The rollers 16a and 1612 should also be made of or lined with wear-resistant material, and moreover said rollers together with the parts supporting them should be as lightweight as possible to reduce the effects of centrifugal force. Conveniently, the small-radius, low-thickness rollers are made from ceramic material, and their inner bore is lined with rings of lowfriction wear-resistant material, e.g. Rilsan, while the pivots a and 15b around which said rings are journalled are made of hardened steel.
The tubular guide arms 8a and 8b are desirably tapered from the cross members 7a, 7b to their free ends so as to provide a contour of equal flexional resistance along 4 the length of said guide arms, reducing the mass and elasticity of the latter and the consequent effects of centrifugal force on the assembly, thereby permitting an additional increase in the maximum angular velocity that can be imparted to the frame.
In the operation of the twisting frame described, it is found that very high speeds of rotation can be used without any tendency to the generation of vibrations. This result is ascribable primarily to the construction of the twisting frame in two separate, generally symmetrical frame sections which are driven separately but synchronously in rotation so that the unitary mass to which centrifugal and other vibration-inducing forces are applied is substantially halved, while the elastic moment of the revolving parts is greatly reduced. Slight fluctuations in the relative velocities and angular positions of the two sections during operation can be readily taken up owing to the free stretch of rope 12 extending between the sections from supporting device 13a to supporting device 13b, which is able to vary somewhat in length so as to take care of misalignment between the guide shafts 8a and 8b at times when the rotation of the two frame sections is slightly off synchronism. The presence of said free stretch of rope between the frame section further makes possible a desirable increase in the over-all axial dimensions of the twisting frame, without any corresponding increase, and in fact with a reduction, of the mass of the revolving parts.
What I claim is:
1. A twisting frame comprising a pair of separate, generally symmetrical frame sections mounted for rotation about a common axis, each section including an axial recessed guide shaft coaxial with said common axis, a crossmernber secured to said guide shaft and projecting radially outward therefrom, and a recessed guide arm secured to an outer end of the cross member and projecting axially therefrom, the two frame sections being mounted so that the respective guide arms thereof are directed towards each other in substantial alignment and with their free ends spaced from one another by a distance which is less than one-half the distance between said cross-members of said frame sections, take-up means supported between said frame sections for rotation about a transverse axis, guide means arranged for guiding a ropelike element from an outer end of one of said axial guide shafts, axially through the recess therein, radially outward along the related cross-member to the related guide arm, axially through the recess therein, across the space between the free ends of the respective guide arms, axially through the recess in the other guide arm, radially inward along the other cross-member to the other axial guide shaft, axially through the recess therein and thence to said take-up means, means for rotating both frame sections in substantial synchronism to twist said rope-like element, and means for simultaneously rotating the takeup means to take up the twisted rope-like element.
2. A twisting frame according to claim 1, including lightweight roller means supported for free rotation from the free ends of said guide arms for applying forces to sadi rope-like element which oppose centrifugal force at the respective ends of its path of travel across said space.
3. A twisting frame according to claim 2, wherein said roller means are made of ceramic material.
4. A twisting frame according to claim 1, including removable strips of wear-taking material extending along radially outer longitudinal areas of the inner surfaces of the recesses in said guide arms for engagement by said rope-like element under centrifugal force.
5. A twisting frame according to claim 1, wherein said guide arms are tapered in contour to provide an equal flexional-resistance profile along their extent.
6. A twisting frame according to claim 1, including a cradle member suspended at opposite ends thereof by way of rotatable bearing means from the axially inner ends of the respective axial guide shafts and supporting said take-up means.
7. A twisting frame according to claim 6, wherein said take-up means comprise a drum mounted for rotation about a transverse axis on a midpoint of said cradle memher.
8. A twisting frame according to claim 7, wherein said take-up means further includes a capstan supported on the cradle member between said drum and the inner end of said other axial guide shaft, and a coiling device supported on the cradle member between said drum and the inner end of said one axial guide shaft, said rope-like element being adapted to be passed from the inner end of the recess of said other axial guide shaft around said capstan and then to said coiling device, thence to be deposited in coils around the periphery of said drum.
References Cited in the file of this patent UNITED STATES PATENTS