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Showing papers on "Reducer published in 1983"


Journal ArticleDOI
TL;DR: In this article, a procedure to calculate the forces on various elements of the speed reducer as well as the theoretical efficiency is presented, and the effects of design parameters on forces and contact stresses are studied.

88 citations


Patent
01 Nov 1983
TL;DR: In this article, a wheel hub of the kind comprising within a hollow body closed by a cover, a reducer having a pinion-carrier, and a brake with a brake disc capable of being subjected to an axial clamping force which is counter-supported by the cover.
Abstract: The invention is applicable to a wheel hub of the kind comprising within a hollow body closed by a cover, a reducer having a pinion-carrier, and a brake with a brake disc capable of being subjected to an axial clamping force which is counter-supported by the cover. According to the invention, the pinion-carrier forms a part which is separate both from the hollow body and from the cover and which bears axially on an abutment itself locked axially on the hollow body, thereby itself closing the hollow body transversely immediately before the cover. The result is that in order to unclamp the brake manually, it is simply necessary to act on the cover. The invention is applicable, in particular, to industrial vehicles, agricultural machines, public works machines and load-handling machines.

18 citations


Patent
02 Nov 1983
TL;DR: In this paper, a modification to a wheel hub of the kind comprising hollow body housing a wheel speed reducer having a pinion carrier which is locked for rotation with the hollow body is described.
Abstract: The invention provides a modification to a wheel hub of the kind comprising hollow body housing a wheel speed reducer having a pinion carrier which is locked for rotation with the hollow body. According to the invention, splined mounting means is provided between the pinion carrier and the hollow body for locking the pinion carrier in rotation with the hollow body. Mounting means of this kind require only a small radial space, and the radial bulk of the assembly can therefore be reduced with this arrangement. The invention is particularly applicable to the hubs of driving wheels for industrial vehicles, agricultural machines, public works machines and load-handling machines.

11 citations


Patent
16 Sep 1983
TL;DR: In this paper, a solenoid-operated detent for engaging a gear of the gate drive motor shaft speed reducer and locking the associated gate, and a key-operated cam for disengaging the detent from the gear.
Abstract: Operators for sliding gates including a solenoid-operated detent for engaging a gear of the gate drive motor shaft speed reducer and locking the associated gate, and a key-operated cam for disengaging the detent from the gear.

11 citations


Patent
24 Jan 1983
TL;DR: In this article, a volumetric analyzer for crude oil sampling is described. But this analyzer is not suitable for use in a crude oil sample collection system, and it is not shown how it can be used in a conventional oil sampling system.
Abstract: For use in a crude oil sampling system which delivers samples in pumped pulse fashion, a volumetric analyzer accumulating the sample is disclosed. In the preferred and illustrated embodiment, the device incorporates a valve which is selectively closed to direct the pumped pulsed sample into the apparatus. It includes a cylinder head attached to a cylinder. In the cylinder, there is a reducer sleeve. The reducer sleeve encloses a piston of selected size. The piston is forced upwardly by sample introduced beneath it. The piston connects with a push rod which in turn extends from the apparatus and which supports a piston follower having a marker cooperative with a scale to indicate the volumetric accumulation below the piston. The piston and reducer sleeve calibrate the apparatus to selected maximum capacities.

9 citations


Patent
02 Feb 1983
TL;DR: In this paper, a boron derivative of a mixture of alkoxylated alcohols and hydroxysulfides was used as a friction reducer for reducing the consumption of fuel.
Abstract: The invention provides a compound effective as a friction reducer in lubricants and fuels, thus reducing the consumption of fuel. The compound is a boron derivative of a mixture of alkoxylated alcohols and hydroxysulfides.

9 citations


Patent
28 Sep 1983

7 citations



Patent
05 Mar 1983
TL;DR: In this article, a bypass pipe is used to charge a reheater before a turbine draft to shorten a time which starts from a boiler ignition and ends to turbine draft and to reduce a life consumption rate due to the thermal stress of the turbine.
Abstract: PURPOSE:To shorten a time which starts from a boiler ignition and ends to a turbine draft and to reduce a life consumption rate due to the thermal stress of the turbine, by a method wherein, by the aid of a bypass pipe, steam is charged to a reheater before a turbine draft. CONSTITUTION:An inlet side of a super heater 5 is connected to a first low-temperature reheat pipe 9 with a low-temperature superhigh-pressure turbine bypass valve 23, and a main steam pipe 6 to a first high-temperature reheat pipe 11 with a high-temperature superhigh-pressure turbine. The first low-temperature reheat pipe 9 is connected to a second low-temperature reheat pipe 14 with a low-temperature high-pressure turbine bypass valve 27, and the first high-temperature reheat pipe 11 to a second high-temperature reheat pipe 16 with a high- temperature high-pressure turbine bypass valve 29. Additionally, the second high- temperature reheat pipe 16 is connected to a condenser 19 with a low-pressure turbine bypass valve 31 and a temperature reducer 32. As noted above, a turbine can be cooled by supplying steam to a first reheat 10 and a second reheater 15, and this permits shortening of a time which starts from a boiler ignition and ends to a turbine draft.

4 citations


Patent
11 Mar 1983
TL;DR: In this article, a charge-coupled device camera with a smear reducer circuit includes a memory (6) for storing a smear signal derived from the pick-up signal, and a level selector circuit (10) for eliminating a noise component contained in the smear signal.
Abstract: A charge-coupled device camera with a smear reducer circuit includes a charge-coupled device (20) for generating a pick-up signal, a memory (6) for storing a smear signal derived from the pick-up signal, and a level selector circuit (10) for eliminating a noise component contained in a smear signal of less than a predetermined level derived from the memory (6). The output of the level selector circuit (10) is subtracted from the pick-up signal thereby to obtain a pick-up signal with the smear reduced and the noise component suppressed.

4 citations


Patent
23 Feb 1983
TL;DR: In this paper, a two-stage speed reducer of the type making use of cycloidal cams was proposed for motion control applications where the elimination of backlash is important, and a first annular bearing surface was provided on one stage having V-shaped cross section with the apex of the V directed outwardly.
Abstract: A two-stage speed reducer of the type making use of cycloidal cams particularly for motion control applications where the elimination of backlash is important. The two stages include sections that are rotatable with respect to each other and any axial or radial movement between the two stages would be a source of backlash. A first annular bearing surface is provided on one stage having V-shaped cross section with the apex of the V directed outwardly. The other stage carries a second similar V-shaped bearing surface in face-to-face relationship with the first bearing surface. Anti-friction means, such as a layer of teflon, is interposed between the two bearing surfaces. Means are provided to apply a preload to the bearing surfaces while limiting the minimum clearance between the surfaces. The resulting bearing is resistant to axial, radial and bending loads and eliminates an important source of backlash enabling the speed reducer to be used for precision motion control applications.

Patent
18 May 1983
TL;DR: In this paper, a circuit element comprising two pressed metal sheets which are welded at 14 so that they define cavities containing different components of the circuit such as a four-way cock, a silencer, a pressure reducer, a valve, a dehydrating cartridge, etc.
Abstract: The invention relates to heat pump circuit elements. It relates to a circuit element comprising two pressed metal sheets which are welded at 14 so that they define cavities containing different components of the circuit such as a four-way cock, a silencer, a pressure reducer, a valve, a dehydrating cartridge, etc. Those elements which must be fixed in a sealed manner are fixed by the welding of a filler material, once the two pressed members have been seam- or spot-welded together. Application to the manufacture of heat pumps

Patent
04 Oct 1983
TL;DR: In this article, a continuous casting equipment and a pipe weld-manufacturing equipment are directly coupled to reduce energy consumption, the cost of equipment and the man-hour, and to improve the efficiency and yield.
Abstract: PURPOSE:To reduce energy consumption, the cost of equipment and the man-hour, and to improve the efficiency and yield, by directly coupling a continuous casting equipment for manufacturing a thin slab and a pipe weld-manufacturing equipment CONSTITUTION:A continuous casting equipment CC and a pipe weld-manufacturing equipment WT are directly coupled Molten steel is cast to a slab S by a rotary caster 4, is soaked, a flaw on the surface is removed, and after that, it reaches a reduction stand 8, in which it is formed to band steel H having a thickness which is suitable for manufacturing a pipe The band steel H is transferred to the equipment WT, a lug part is cut off, width is prescribed, a shape is made proper, a groove is formed, and after that, it is worked to a tubular open pipe by an electric resistance pipe weld-manufacturing machine 12, its edge part is welded and made to press-contact, and after that, a generated beam is removed As for a formed base pipe Pm, the metallic structure is homogenized by an annealer 13, the outside diameter is reduced to a prescribed size by a pipe stretch reducer 14, and it is worked to a product steel pipe P and is cut to prescribed length by a cutting machine 15 In this regard, it is also possible to install the equipment CC, WT consecutively through a hot rolling plate manufacturing equipment

Patent
12 Jul 1983
TL;DR: In this paper, the 2-roll type caliber rolls of a stretch reducer in continuous rolling mills for seamless pipes having plural caliber roll stands exchangable with 3-roll-type caliber rolls are exchanged.
Abstract: PURPOSE:To prevent the generation of flaws on the surfaces of formed pipe materials by making the 2-roll type caliber rolls of a stretch reducer in continuous rolling mills for seamless pipes having plural caliber roll stands exchangable with 3-roll type caliber rolls. CONSTITUTION:In a stretch reducer 26 for seamless steel pipes for reducing a hollow reducer blank pipe 22 continously after rolling a heated solid billet to said reducer blank pipe with a piercer and a mandrel mill, the housing of 3-roll type caliber rolls 26b and the housing of 2-roll type caliber rolls 26a are made exchangeable, and the 2-roll caliber rolls 26a are incorporated into the final stand 26n and the stand 26n-1 in the fore stage of said stand. The 3-roll type caliber rolls 26b are incorporated into stands 26-1-26n-2 on the upper stream side than the same. Roll gaps are variable, and seamless pipes having no flaws on the surface are produced without spoiling quick changing functions.

Patent
16 Aug 1983
TL;DR: In this article, the authors proposed a method to obtain a titled pipe which is free from deformation and crushing by external pressure and assures >=52% electric conductivity by forming a thermosetting Al alloy tape which is attached longitudinally on an optical cable into a pipe shape and reducing the diameter of the pipe then treating the same under heating.
Abstract: PURPOSE:To obtain a titled pipe which is free from deformation and crushing by external pressure and assures >=52% electric conductivity by forming a thermosetting Al alloy tape which is attached longitudinally on an optical cable into a pipe shape and reducing the diameter of the pipe then treating the same under heating. CONSTITUTION:A thermosetting Al alloy tape 11 let off from a reel 12 is fed through a slitter 13 to a forming unit 14, and is attached longitudinally on an optical cable 16. Both side edges of the tape 11 are rounded with a forming die 14 to form the tape into a cylindrical shape, the butt parts whereof are welded continuously with an electric welding device 17 to form a pipe 18 contg. the cable 16. The pipe 18 is detected of flaws with a magnetic inspection device 25, and is then fed to a reducer 19 for diameter by means of an endless track 26 so that the pipe is reduced successively in diameter by a die 20 which regulates the outside diameter of the pipe 18 and a floating plug 27 which regulates the bore of the pipe 18. The pipe 18 is hardened in a heat treatment device 31, whereafter the pipe is inspected of flaws with the device 25 and is taken up on a reel 32.


Patent
30 Jun 1983
TL;DR: In this paper, a stretch reducer for seamless pipes is used to adjust the outside diameter of the seamless steel pipe obtained by stretch reducing with a stretch reduction with a 3-roll type by using sizers, and the gaps of the grooved rolls of said sizers are controlled so as to eliminate the difference between the Dc and a target outside diameter.
Abstract: PURPOSE:To control the finish outside diameter of a finish rolled pipe and to prevent surely the out-of-tolerance in the outside diameter of products by adjusting finely the outside diameter of the seamless steel pipe obtained by stretch reducing with a stretch reducer of 3-roll type by using sizers. CONSTITUTION:In a stretch reducer for seamless pipes which stretch-reduces a base pipe with a 3-roll type hot stretch reducer 26 arter heating the same in a reheating furnace 24, adjusts finely the outside diameter thereof with plural units of sizers 31 consisting of grooved rolls of 2 roll type which re synchronized with rolling speeds and are adjustable of rolling reduction, and allows the pipe to cool with a cooling head 30, the hot outside diameter Do and temp. To of the finish rolled pipe right after the outlet side of said sizers 31 are detected, and in a control device 36, a cold finish outside diameter Dc is determined from these detected values, and the gaps of the grooved rolls of said sizers 31 are controlled so as to eliminate the difference DELTAD1 between the Dc and a target outside diameter DT.

Patent
16 Mar 1983
TL;DR: In this article, a coupled part is formed by coupling preceding and succeeding base pipes while running both pipes in the axial direction thereof between a reheating furnace and a stretch reducer, where the tension during rolling is maintained always in the state in which the pipes are rolled in all stands.
Abstract: PURPOSE:To prevent the thickening phenomena at the preceding and succeeding ends of pipes by coupling preceding and succeeding base pipes while running both pipes in the axial direction thereof between a reheating furnace and a stretch reducer. CONSTITUTION:In the stage of reducing the metallic base materials heated in a reheating furnace with a stretch reducer, first a cylinder 33 which is threaded on inside and outside surfaces is put on the preceding end of a successing SR base pipe 1'. The part thereof is compressed by a compressing machine to the diameter smaller than the inside diameter of a preceding base pipe 1''. The preceding end part of the pipe 1' compressed by the cylinder 33 put thereon is inserted into the succeeding end part of the pipe 1'', whereby a coupled part is formed. The coupled part is compressed with a compressing machine to the diameter smaller than the outside diameter of the SR product. It is effective to cool the coupled part forcibly by water cooling or the like. Thus the tension during rolling is maintained always in the state in which the pipes are rolled in all stands and the thickening phenomena are prevented.

Patent
30 Jun 1983
TL;DR: In this paper, a reducer blank pipe is drawn to a prescribed outside diameter and wall thickness with a stretch reducer, and a floating plug is inserted into the pipe to apply rolling reduction forcibly to the wall thickness of the pipe material.
Abstract: PURPOSE:To produce a finished pipe having wall thickness distributions which are uniform longitudinally and circumferentially, by providing a finishing stand which uses a floating plug to stretch reducers for the pipe to be produced with respective rolling stages of piercing, stretching and drawing CONSTITUTION:A reducer blank pipe 22 which is obtained by working a round bar 10 with a piercer 14, a stretch rolling mill 18 using a mandrel 20, etc is heated in a reheating furnace 24 and is drawn to a prescribed outside diameter and wall thickness with a stretch reducer 26, whereby a finished pipe 28 is obtained A finishing stand 26 A is provided at the final stand of the reducer 26 or near the same and a floating plug 30 is inserted into the pipe 22 to apply rolling reduction forcibly to the wall thickness of the pipe material, whereby the finished pipe 28 having wall thickness distributions which are uniform in longitudinal and circumferential directions is obtained Further, the length of the crops at both ends of the pipe 28 is decreased considerably, whereby the yield of the material is improved

Patent
15 Jul 1983
TL;DR: In this paper, the wall thickness distribution in the longitudinal direction of a seamless pipe uniform by controlling a piercer was obtained by obtaining the target wall-thickness distribution of a pipe obtained after piercing.
Abstract: PURPOSE:To make easily and surely the wall thickness distribution in the longitudinal direction of a seamless pipe uniform by controlling a piercer, by obtaining the target wall thickness distribution in the longitudinal direction of a pipe obtained after piercing, required to make the wall thickness distribution of a roll-finished pipe at the exit side of a stretch reducer uniform CONSTITUTION:As a blank material, a round steel bar 10 is continuously heated in a rotary hearth type heating furnace 12, and after piercing it by a piercing mill 14, the pierced blank pipe is stretched by a mandrel mill 20 and is successively drawn by a stretch reducer 26 after being reheated in a reheating furnace 24 In such a method of the wall thickness controlling of a seamless pipe, the wall thickness distribution of a roll-finished pipe 28 at the exit side of the reducer 26 is previously estimated to obtain the target wall thickness distribution in the longitudinal direction of the hollow rough blank pipe 16 obtained after piercing, required to make said estimated wall thickness distribution uniform Then, the piercing conditions of piercer 14 is controlled so as to obtain said target wall thickness distribution

Patent
13 Apr 1983
TL;DR: In this paper, an end working machine is provided in front and rear of a reheating furnace for base pipes, and the tail end part 1 of a preceding base pipe is worked to a small diameter part having screw-like rugged parts.
Abstract: PURPOSE:To reduce the inadequate parts in the sectional sizes in the end parts of pipes and to improve yield, by reducing the diameter in the end parts of base pipes, reheating the same and fitting and press sticking the top and tail parts of the preceding and succeeding base pipes then subjecting the pipe to endless rolling CONSTITUTION:End working machines 14 are provided in front and rear of a reheating furnace 15 for base pipes, and the tail end part 1 of a preceding base pipe 11 is worked to a small diameter part having screw-like rugged parts The top end part 2 of a succeeding base pipe 12 is worked to a small diameter part of which the inside diameter fits into the part 1 A pressing device 16 fits the parts 1, 2 of the pipes 11, 12 worked with the machines 14 in a coupling machine 19 Pinch rolls 17 press and stick the parts 1, 2 in the machine 19 by operating cooperatively with the device 16 Prior to the press sticking, the part 1 of the pipe 11 worked to the small diameter part having the screw-like rugged parts is cooled with a cooler 18 and the coupled parts of the parts 1, 2 of the base pipes coupled by the press sticking are cooled with a cooler 20 The coupled pipe is subjected to endless rolling with a stretch reducer 21, and the coupling parts are cut away with a cutter 22

Patent
28 Apr 1983
TL;DR: In this article, a parallel linkage is arranged vertically pivotally on a stand and a size reduction device, comprising feed hopper and size reducer, is hinged to it, with the lower part of which serves as liquid pan for the liquid discharged from openings.
Abstract: Apparatus for the size reduction of empty plastic containers of any shape, in particular empty oil canisters, a parallel linkage (2) being arranged vertically pivotally on a stand (1) and having hinged to it a size reduction device, comprising feed hopper (3) and size reducer (4), the housing (9) of the size reducer (4) having on the underside an opening (10) which opens out into a collector (11) for the size-reduced material (12), and the collector (11) being held in a mobile collector holder (13), the lower part of which serves as liquid pan for the liquid discharged from openings (14) on the underside of the collector (11).

Patent
11 Oct 1983
TL;DR: In this paper, the authors proposed a method to make the wall thickness of a blank pipe uniform by controlling the tension between stands, by detecting the bulge width at the time of stretch-reducing, and controlling the peripheral speed of a roll at each stand basing on the distribution of bulge-width of the pipe in the longitudinal direction.
Abstract: PURPOSE:To make the wall thickness of a blank pipe uniform by controlling the tension between stands, by detecting the bulge-width at the time of stretch- reducing, and controlling the peripheral speed of a roll at each stand basing on the distribution of the bulge-width of the pipe in the longitudinal direction. CONSTITUTION:In a mandrel mill, the distribution of bulge-width in the longitudinal direction, detected by a bulge-width detecting device 11 at the time of elongator-rolling, is transmitted to a bulge-width recording device 12 and then is stored in a host arithmetic device 13. The device 13 calculates to obtain a roll- peripheral-speed controlling pattern in accordance with a calculating formula basing on the distribution of the bulge-width in the longitudinal direction. Then in stretch-reducing a blank pipe by a stretch reducer 14, a driving motor at each stand is controlled in accordance with the calculated controlling pattern of the peripheral speed of a roll through a drive-controlling device 15.



Patent
12 Mar 1983
TL;DR: In this paper, a dynamic vibration reducer is used to absorb the vibration of an air conditioning machine by aligning its natural vibration frequency almost to a rotary frequency or the like of the compressor.
Abstract: PURPOSE:To absorb vibration of an air conditioning machine, by setting a dynamic vibration reducer to the wall surface of an enclosed vessel of a compressor, fixing a weight to the dynamic vibration reducer through an elastic member and aligning a primary natural vibration frequency of the dynamic vibration reducer to a rotary frequency or the like of the compressor. CONSTITUTION:A weight 6a is provided to the end of an elastic member 6b of a dynamic vibration reducer 6, set to a compressor 1, and embedded to a hollow 4a in a separator plate 4. The dynamic vibration reducer 6, set to an enclosed vessel by aligning its natural vibration frequency almost to a rotary frequency or the like of the compressor 1, is vibrated in a reverse phase to vibration of the compressor 1, and reaction torque in supplied to the compressor 1 through the elastic member 6b. In a setting place of the dynamic vibration reducer 6, torque due to vibration of the compressor 1 and reaction torque fed from the dynamic vibration reducer 6 are cancelled with each other, and a node of vibration is generated, as a result, overall vibration of the compressor 1 can be reduced.

Patent
17 Sep 1983
TL;DR: In this article, a detachable magnetic force generating apparatus is mounted at a position contacted with the lubricant in the casing of the gear reducer of a copying machine to remove an iron powder in a lubricant and to eliminate rotational irregularity and backlash.
Abstract: PURPOSE:To remove an iron powder in a lubricant and to eliminate rotational irregularity and backlash, by mounting a detachable magnetic force generating apparatus at a position contacted with the lubricant in the casing of the gear reducer of a copying machine. CONSTITUTION:A permanent magnet 8 is integrally attached to the leading end of a hermetically closing bolt 7 for closing a discharge port of a lubricant in the casing 2 of the gear reducer 1 of a copying machine. By this mechanism, an iron powder generated by the abrasion of a speed reducing gear group 3 due to the operation of the gear reducer 1 is attracted by the permanent magnet 8 to be removed from the lubricant 10. Therefore, the abrasion of the speed reducing gear group 3 due to the iron powder and troubles such as rotational irregularity thereof or the like are prevented as well as durability thereof is also enhanced.

Patent
14 May 1983
TL;DR: In this article, a semi-anechoic room with sound absorbing wedges over the entire part, a dynamo and a test gear speed reducer were used to measure gear noises in the transient stage corresponding to rated running.
Abstract: PURPOSE:To permit prediction of gear noises in the stage of rated running with good accuracy by measuring gear noises in the transient stage corresponding to rated running CONSTITUTION:A semi-anechoic room 10 enclosed with sound absorbing wedges 11 over the entire part, a dynamo 12 as a driving machine installed in a dynamo chamber 13, a test gear speed reducer 16 of which input side 16a is connected to the extension shaft 14 of the dynamo via a gear coupling 17, a speed-increasing gear 18 connected to the output side 16b via a gear coupling 19, and a regenerative motor 20 as a brake device connected to the gear 18 via a coupling 21 are provided and the entire part is covered with a soundproofing cover 22 A test gear 16 is used in the test gear speed reducer of such testing machine and the gear noises in the transient stage corresponding to rated running are measured with a noise meter, whereby the gear noises in the state of rated running are predicted

Patent
23 Aug 1983
TL;DR: In this paper, a safety fitting with pressure reducer and backflow preventer is constructed in such a way that the valve disc is displaceable on the valve spindle against a spring up to a stop.
Abstract: A safety fitting with pressure reducer and backflow preventer is constructed in such a way that the valve disc (30) of the pressure reducer is displaceable on the valve spindle (32) against a spring (34) up to a stop (38). Consequently, the pressure-reducing valve (30, 24) at the same time acts as a backflow preventer. In an advantageous design of a safety valve, the diaphragm disc (64) has a safety-valve seat (66) which is held in contact with a safety-valve seat (68) not only by the load spring (70) of the pressure reducer but also by a second load spring (72) supported on the valve spindle (32). During a pressure rise after closing of the pressure-reducing valve, the additional load spring (72) is overcome and the safety valve (66, 68) opens.

Patent
10 Feb 1983
TL;DR: In this article, the viscous resistance of gas was exploited to obtain an excellent slackened twisted line without bending the cores by reducing the tension of optical fiber cores with a tension reducer and thrusting the cores into a core holding pipe with a core feeder.
Abstract: PURPOSE:To obtain an excellent slackened twisted line without bending the cores by reducing the tension of optical fiber cores with a tension reducer and thrusting the cores into a core holding pipe with a core feeder by making use of the viscous resistance of gas CONSTITUTION:Each optical fiber core 2 is artificially passed through the inlet 22 of a core feeder 17, the gas reflux preventing hole 23 and the gas flowing hole 24 Pressurized air is fed to the gas inlet 20 through a pressure regulating valve 31 to apply constant thrusting force to the core 2 Cores 2 from each core strand bobbin are wound around the winding cylinder 33 of a tension reducer 32 having a central shaft 34 which rotates in the arrow direction A tape 3' fed from each tape bobbin 6 is formed into a pipe 3 with a forming jig 7 Cores 2 fed from core bobbins 5 are thrust into the pipe 3 with the feeder 17 after reducing the tension with the tension reducer 32, and they are twisted together by the rotation of a main shaft 4 to obtain an excellent slackened twisted line without bending the cores