Thompson, Walter (42 Burnaby Boulevard, Toronto, Ontario M4R 1B4, CA)
| 1. | A flyer bow machine for twisting or twinning wires or cables having a rotatable bow section along which a wire or cable travels longitudinally during the twisting or twinning operation, and further comprising a carrier strip extending along a longitudinal surface of said bow against which the wire or cable travels, and a carrier strip drive mechanism which moves said carrier strip in the direction that said wire or cable travels. |
| 2. | A flyer bow machine as claimed in Claim 1 wherein said carrier strip travels at a speed which is within 5% of the speed that said wire or cable is traveling. |
| 3. | A flyer bow machine as claimed in Claim 1 wherein said carrier strip travels at a speed which is within 1 % of the speed that said wire or cable is traveling. |
| 4. | A flyer bow machine as claimed in Claim 1 wherein said carrier strip travels at a speed which is within 0. 1 % of the speed that said wire or cable is traveling. |
| 5. | A flyer bow machine as claimed in Claim 1 wherein said bow has an inside surface and an outside surface, and said carrier strip and said wire or cable travel in the same direction along the inside surface of said bow. |
| 6. | A flyer bow machine as claimed in Claim 5 wherein said carrier strip travels in an opposite direction along the outside surface of said bow relative to its direction of travel along the inside surfaced said bow. |
| 7. | A flyer bow machine as claimed in Claim 1 wherein said carrier strip passes through a pulley positioned adjacent to each end of the bow so as to move said carrier strip from one side of the bow to the other. |
| 8. | A flyer bow machine as claimed in Claim 7 wherein at least one of said pulleys is a drive pulley connected to a motorized propulsion means, which acts to propel said carrier strip. |
| 9. | A flyer bow machine as claimed in Claim 8 wherein said motorized propulsion means comprises an electric motor connected to said driye pulley. |
| 10. | A flyer bow machine as claimed in Claim 9 wherein said electric motor is inter connected to said drive pulley through a differential gear box. |
| 11. | A flyer bow machine comprising a flyer bow having opposing ends, an inside surface and an outside surface, a carrier strip which travels in one direction on the inside surface of said bow, and in the opposite direction on the outside surface of said bow, pulleys positioned adjacent the ends of said bow. for moving said carrier strip from one surface of said bow to the other, and drive means for propelling at least one of said pulleys, and thus propelling said carrier strip. |
| 12. | A flyer bow machine as claimed in Claim 11 additionally comprising a tensioner for maintaining an essentially constant tension on said carrier strip. |
Field of the Invention [0002] The present invention relates to the field of machines for the production of stranded wire or cable, and in particular. relates to such machines which utilize a flyer bow.
Background of the Invention [0003] Double twist, single twist, skip and other wire or cable manufacturing machines are commonly used to prepare various types of wire and cables (which can include coated or uncoated wires, cables, fibre optic cables and the like). The resultant wires and cables are of the type that include a plurality of twisted wires which are manufactured in either one stage or in two or more stages.
[0004] In the case where cables are manufactured in two stages, the twisted wires are first prepared by twisting the wires together by means of so-called twinning or pairing machines.
Twisted wires are then made up into communications cables by means of for example, stationary take-ups, rotating take-ups (also called drum twisting machines) or other types of rotating equipment.
[0005] One form of equipment conventionally used for twisting two, three or four wires is the double twist machine. The resulting twisted elements are called pairs, triads or quads.
[0006] This equipment includes a bobbin cradle around which is arranged a rotatable frame or flyer bow (also simply referred to as a"bow") which is driven to turn around the cradle.
Wires to be twisted may be supplied from bobbins (or reels) on the bobbin cradle inside the twinning cage, twisted as they are fed to the rotating flyer bow, and then taken up on a take-up reel outside the twinning cage. As the wire travels along the flyer bow, it typically travels on the inside of the bow in a guide path, so that the"bow wire"is kept from flying off of the bow.
Centrifugal forces from the rotating bow act to force the wire against the inside edge of the bow.
[0007] The aforementioned arrangement is referred to as an"inside-out"machine. The wires to be twisted, however, may also be supplied from outside the twisting cage and taken up on a bobbin arranged within the bobbin cradle. The latter configuration is sometimes referred to as an"outside-in"machine.
[0008] Outside-in machines are generally preferred in individual twisting machines since the wire may be supplied from storage facilities of simple construction and greater capacity. In this case, the bobbin cradle within the twisting cage is also required to hold only a single bobbin.
The outside-in machine is also readily adaptable to use with a greater number of wires.
[0009] In a typical double twist machine, the wire or cable is twisted once as it enters the flyer bow, and twisted again as it exits the flyer bow. The twisted elements so manufactured are directed to any type of take-up (e. g. , stationary or rotating take-ups, single or double twist machines, capstan or extrusion lines) for laying up twisted wires to form a communication cable.
This is typically done in one operation.
[0010] The wire twisting machines can be arranged horizontally or vertically, depending on the preferred plant layout. Examples of such machines, utilizing a flyer bow are described in US Patent No. 5,966, 917, and in US Patent No. 5,400, 579. As such, these types of machines are well known in the wire and cable production art, and will hereinafter be referred to as"flyer bow machines". Accordingly, use of this term is meant to cover any machine for wire or cable production which involves the use of a flyer bow.
[0011] In order to maximize production on these flyer bow machines, the feed rate of the feed wire or cable can reach speeds in excess of 250 m/min. As a consequence of increasing the line speed, the rotational speed of the flyer bow must also be increased in order to maintain a consistent lay in the wire or cable produced. As such, the rotational speed of the flyer bow must be increased by a corresponding amount, and may reach speeds of up to 3000 rpm or more.
However, the various wire or cable production machines utilizing flyer bows are production limited by, inter alia, the maximum rotational speed of the flyer bow.
[0012] The maximum rotational speed of the bow is limited by factors such as, the centrifugal force acting on the wire as it travels along the bow wire path, Coriolis forces, and the frictional forces from the surface of the bow. These forces all act to increase the tension on the wires beings produced. All wires, whether electrical or mechanical, have a maximum allowable tension that can be sustained for a given time period before various types of damage is created.
As such, the maximum production speed of the production machinery is limited by the need to avoid or minimize unacceptable levels of this damage.
[0013] Machine designers have made attempts to limit centrifugal force. Coriolis force, and the friction coefficient of the bow, all with limited success. The present application seeks to address this issue and provide for higher production speeds and/or higher quality wire or cables by reducing or minimizing the effect of the tension on the wire or cable as it is being twisted or twinned.
[0014] To overcome the difficulties of the prior art machines, it would be advantageous to provide a flyer bow wire production machine wherein the tension exerted on the wire being produced was reduced, when compared to conventional machines, and thus allow for wires or cable to be produced having improved quality and/or, to produce wires or cable with acceptable quality at greater production speeds.
Summary of the Invention [0015] Accordingly, it is a principal advantage of the present invention to provide a flyer bow wire machine which reduces the frictional forces resulting from the centrifugal forces and/or the Coriolis forces which act on the wire as it travels along the bow wire path.
[0016] It is a further advantage of the present invention to provide a flyer bow wire machine which maintains or reduces the tension on the wire being produced as it travels along the bow wire path, and more generally, as it passes through the flyer bow wire machine.
[0017] The advantages set out hereinabove, as well as other objects and goals inherent thereto, are at least partially or fully attained by using a flyer bow machine having a traveling carrier strip that moves longitudinally along the bow wire path, at a speed which preferably closely matches the speed of the wire traveling along the bow wire path.
[0018] Accordingly, in one aspect, the present invention provides a flyer bow machine for twisting or twinning wires or cables having a rotatable bow section along which a wire or cable travels longitudinally during the twisting or twinning operation. and further comprising a carrier strip along a longitudinal surface of said bow against which the wire or cable travels, and a carrier strip drive mechanism which moves said drive strip in the direction that said wire or cable travels.
[0019] In a further aspect, the present invention also provides a flyer bow having an inside surface and an outside surface, a carrier strip which travels in one direction on the inside surface of said bow, and in the opposite direction on the outside surface of said bow, pulleys located at or near the ends of said bow for moving said carrier strip from one surface of said bow to the other, and drive means for propelling at least one of said pulleys, and thus propelling said carrier strip.
[0020] In a still further aspect. the present invention also provides for the use of the flyer bow machine, or the flyer bow, in the production of wire or cable.
[0021] In the present application, the term"flyer bow machine"refers to any of the known wire or cable production machines which utilize a flyer bow. The present application is primarily directed to the production of wire or cable, which can include coated or uncoated strands of wire or cable, which can include, for example, optical fibre cable. The wire or cable can be produced from any suitable ferrous or non-ferrous metal, including for example, copper, steel or aluminum, but might also be prepared from any other material suitable for use as a wire or cable, or component thereof, such as plastics, fibre optics and the like.
[0022] However, the skilled artisan will be aware that flyer bow machines for wire and cable production are used in a wide variety of applications, and to produce a wide variety of wire and cable products. Accordingly, while the present application is hereinafter described with particular reference to the wire industry, the skilled artisan would be aware that the present application is equally applicable in numerous other applications.
[0023] The primary feature of the present invention is the use of a traveling carrier strip on the flyer bow which moves longitudinally along the bow wire path. Preferably, the carrier strip moves at a speed which closely matches the wire speed of the wire moving along the bow wire path, and as such, the carrier strip speed is within 5% of the speed of the wire speed. More preferably, the carrier strip speed is within 1% of the speed of the wire speed, and most preferably is within 0.1 % of the speed of the wire speed.
[0024] In operation, the carrier strip moves preferably along the inner surface of the flyer bow in the same direction, and at the same speed, as the wire. The wire is"pressed"against the carrier strip by the centrifugal force of the rotating bow. However, by providing a moving carrier strip, the frictional force of the wire pressing against the bow, is reduced and/or eliminated. With the elimination or reduction of this frictional force, the tension on the wire as it passes through the flyer bow machine is reduced. As such, the line speed and/or the rotational speed of the bow can be increased in order to prepare wires of improved quality, and/or produce wires of equal quality at increased speeds.
[0025] The flyer bow can be constructed of the materials known in the prior art.
Typically, the flyer bow is made of a fibreglass material, or of a carbon fibre material. However, depending on the rotational speed, and the wire line speed, suitable materials of construction for the bow would be well known to the skilled artisan. Normally, there are two bows on a given flyer bow machine, and although a wire typically only travels on one bow, flyer bow machines are known where a wire is fed along each bow. The bows are preferably balanced so that rotational vibrations caused by the bow are minimized.
[0026] The endless carrier strip is preferably a loop of an appropriate material which travels in an overall circular pattern. This might include an arrangement wherein the carrier strip travels up the inside of one bow, and returns on the inside of the opposite bow. Alternatively, the carrier strip might travel up and return on one side of the bow. However, preferably, the carrier strip travels longitudinally up the inside of the bow, passes through a pulley, and returns, traveling in the opposite direction, on the outside of the bow. A second pulley would then return the carrier strip from the outside to the inside of the bow. Normally, the wires passing along the bow (the"bow wires") would contact the carrier strip on the inner surface of the bow.
[0027] At least one of the pulleys is preferably linked to a carrier strip drive means in order to move the carrier strip at a selected speed.
[0028] The carrier strip can be flat or some other acceptable shape. For example, a concave shape will position the wire in the centre of the carrier strip, and aid in reducing any damage resulting from the Coriolis force. The carrier strip is preferably an"endless"belt and can be made of any material which provides acceptable strength properties for the intended application. The carrier strip can be made of fabric or plastic, but more preferably is made from a ferrous or non-ferrous material, and most preferably is made of a high tensile, metal alloy, such as steel, which would have good strength properties, while resisting stretching at the intended speeds.
[0029] The carrier strip is preferably held in position within a carrier strip channel on the inside surface of the bow, together with the bow wire, by a wire guide. The return path of the carrier strip, on the outside surface of the bow, can be established using several strips which support and maintain the carrier strip in position on the outside of the bow.
[0030] In a preferred embodiment, the carrier strip is driven by a precision variable speed motor and control, and preferably includes a differential gear box. As such, the speed of the carrier strip can be closely controlled and matched to the speed of the bow wire. The differential gear box is preferably connected to a flyer shaft by timing belts and pulleys such that the flyer bow rotation has no effect on the speed of the carrier strip. The flyer shaft is preferably concentric with a carrier strip drive shaft, and is supported by ball bearings, and in turn, drives a set of spur gears and the like, to ultimately drive the carrier strip drive pulley.
[0031] Preferably, a spring tensioning device would also be provided in order to maintain a desired amount of tension on the carrier strip.
Brief Description of the Drawings [0032] Embodiments of this invention will now be described by way of example only in association with the accompanying drawings in which: [0033] Figure 1 is a plan view of a flyer bow machine according to the prior art; [0034] Figure 2 is a plan view of the flyer bow machine of the present invention; [0035] Figure 3 is a plan view of a flyer bow section of the device of Figure 2; and [0036] Figure 4 is a partial, perspective view of a portion of the flyer bow of Figure 3.
Detailed Description of the Preferred Embodiments [0037] The novel features which are believed to be characteristic of the present invention, as to its structure, organization, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following drawings in which a presently preferred embodiment of the invention will now be illustrated by way of example only. In the drawings, like reference numerals depict like elements.
[0038] It is expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention.
[0039] The operation and design of a prior art flyer bow machine is well described in detail in a variety of documents including, for example, US Patent No. 5400549. In general, however, a prior art flyer bow machine 10 is shown in Figure 1. In this example, the flyer bow machine has a support frame 11, and is an inside-out machine have two shrouds 12 and 14 each containing a reel of a coated, single strand wire, located within a main body section 20. The reels within shrouds 12 and 14 are rotated by electric motor 16 at a speed such that wires'W"are fed from the reels at essentially the same speed as the production line speed.
[0040] At each side of main body section 20 are bows 22 and 24, which are connected by brackets 26 to a central axle 28, which in turn is connected to an electric motor (not shown) through pulley 29 used to rotate bows 22 and 24 about main body section 20. A strand of wire is fed from each reel within shrouds 12 and 14 and passes around single pulleys 30, to double pulley 32. The two wires, in side-by-side configuration are then fed through the center of body section 20 to a first bow pulley 34, and then on to bow 22. Bows 22 and 24 rotate around main body section 20, so that a first twist is applied to the wires. The"bow wires"then travel along the inside of bow 22, and pass through various wire guides 36. At the end of bow 22, the wires are fed to a second bow pulley 38, and then exit bow flyer machine 10. As the bow wires exit bow 22, a second twist is provided, and thus a double twist is provided.
[0041] The wires are then fed through a capstan (not shown), which capstan is responsible for pulling the wires through the bow flyer machine. After the capstan, the twisted or twinned wires are then collected on a take-up reel (not shown).
[0042] In operation, the line speed of the wire feed and the rotation rate of the bows can be adjusted to provide the appropriate production rate for the wire tension encountered, while providing the desired lay distance. In some embodiments, the rotation rate can be 2250 RPM or higher providing a twist rate of double that amount, and a line speed of 250 m/min, or higher.
[0043] In Figure 2, a flyer bow machine 100 according to the present invention is shown.
In this embodiment, machine 100 is set at an angle, but is basically similar to machine 10 shown in Figure 1. Machine 100 also includes a flyer bow assembly, which is shown in greater detail in Figure 3.
[0044] In this embodiment, bow 120 includes a first pulley 122, a driven pulley 124, a spring tensioner 126, a pulley motor 135, and a drive mechanism 130 for rotating the driven pulley 124, which consists of a differential gear box 136, and a series of gears and the like.
[0045] In operation, pulley motor 135 is a precision variable speed motor and control which is connected to differential gear box 136 using a belt and pulleys 145. The output of differential gear box 136 is transferred to flyer shaft 139 through a second series of belts and pulleys 146. The flyer shaft is concentric with a carrier strip drive shaft 138, and supported in ball bearings which in turn, drives a set of spur gears 140, and then a set of bevel gears 141 onto the driven pulley 124. Carrier strip 110 extends along the inside of bow 120, and passes around driven pulley 124. Carrier strip 110 then extends along the outside of bow 120, and passes around pulley 122 to return to the inside of bow 120. Spring tensioner 126 maintains a suitable level of tension on carrier strip 110. Carrier strip 110 is moved around bow 120 as a result of the rotation of driven pulley 124 at a rate of speed substantially matched to the speed of the wire moving along the inside of bow 120.
[0046] Driven pulley 124 also acts as the flyer bow wire exit pulley so that the wire W will exit the bow at this pulley.
[0047] It should be noted that the line speed of the carrier strip control system can be a "master", which means that the wire or cable linear speed is the same as the carrier strip. An auxiliary capstan can control the cable speed and the carrier strip control would be electronically speed matched to the capstan. In this configuration the carrier strip can be either faster than the wire or cable speed which will reduce the tension, or slower than the wire or cable speed which will increase the cable tension. As such, it can be seen that various control means are provided for controlling the tension in the wire or cable, and thus produce a desired effect in tension control.
[0048] Figure 4 shows a partial, perspective view of a portion of the flyer bow of Figure 3. Bow 120 is made of fibreglass, and has an inner surface on which the carrier strip 110 travels.
Carrier strip 110 is contained within a carrier strip channel 113 formed using carrier strip guide 112, on the inner surface of bow 120. Carrier strip 110 passes in the opposite direction on the outside of bow 120, and is held in position by wire guide strips 114. For reference, two wire strands W are shown against carrier strip 110 on the inside of bow 120.
[0049] Thus, it is apparent that there has been provided, in accordance with the present 20 invention, a flyer bow machine which fully satisfies the goals, objects, and advantages set forth hereinbefore. Therefore, having described specific embodiments of the present invention, it will be understood that alternatives, modifications and variations thereof may be suggested to those skilled in the art, and that it is intended that the present specification embrace all such alternatives, modifications and variations as fall within the scope of the appended claims.
[0050] Additionally, for clarity and unless otherwise stated, the word"comprise"and variations of the word such as"comprising"and"comprises", when used in the description and claims of the present specification, is not intended to exclude other additives, components, integers or steps.
[0051] Moreover, the words"substantially"or"essentially", when used with an adjective or adverb is intended to enhance the scope of the particular characteristic; e. g. , substantially planar is intended to mean planar, nearly planar and/or exhibiting characteristics associated with a planar element.
[0052] Further, use of the terms"he","him", or"his", is not intended to be specifically <BR> directed to persons of the masculine gender. and could easily be read as"she", "her", or"hers", respectively.
[0053] Also, while this discussion has addressed prior art known to the inventor, it is not a 10 admission that all art discussed is citable against the present application.