US3691791A - Slip-clutch - Google Patents

Slip-clutch Download PDF

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Publication number
US3691791A
US3691791A US70036A US3691791DA US3691791A US 3691791 A US3691791 A US 3691791A US 70036 A US70036 A US 70036A US 3691791D A US3691791D A US 3691791DA US 3691791 A US3691791 A US 3691791A
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US
United States
Prior art keywords
rope
clutch
spring
drum
slip
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US70036A
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English (en)
Inventor
Tetsuji Yoshii
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP45007928A external-priority patent/JPS5031807B1/ja
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Application granted granted Critical
Publication of US3691791A publication Critical patent/US3691791A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D7/00—Slip couplings, e.g. slipping on overload, for absorbing shock
    • F16D7/02—Slip couplings, e.g. slipping on overload, for absorbing shock of the friction type
    • F16D7/021—Slip couplings, e.g. slipping on overload, for absorbing shock of the friction type with radially applied torque-limiting friction surfaces

Definitions

  • the present invention relates to a slip-clutch used as a frictional torque transmission in a tope take up mechanism of a tape recording and reproducing apparatus and the like.
  • a conventional frictional torque transmission of this kind employs a pair of rotatable member or tape urged against each other by spring means for the transmission of torque from one of the discs to the other.
  • the coefficient of friction between the frictionally sliding surfaces of the opposite driving and driven members tends to increase with the variation in the surface condition due to wear of the surfaces, stain and blot on the surfaces and with the rise of the temperature at the surfaces.
  • the increase in the friction coefficient amounts to two to three times as compared with that in normal or initial operation.
  • the torque transmitted by the conventional clutch therefore, varies in proportion to the variation in the friction coefficient in prolonged operation of the device.
  • the conventional friction clutch has an additional disadvantage that the frictionally sliding surfaces have therebetween a coefficient of friction which is largely varied with the difference in the direction in which the friction members are rotated. This variation gives rise to various troubles during practical operation of the clutch for prolonged period of time.
  • a slip-clutch including a torque-transmission means comprising a cylindrical body and a length of frictional slider extending around the outer surface of said cylindrical body in frictional sliding engagement therewith, said slider being mounted on a support in such a manner that the leading end of said slider as viewed in the rotation of said cylindrical body in one direction is connected to said support through a spring means while the trailing end is directly secured to said support.
  • a bi-directional slip-clutch including a torque-transmission means comprising a cylindrical drum member and a length of a rope having spiral turns extending around said drum in frictional sliding engagement therewith, spring means for resiliently connecting the opposite free ends of said rope to a support therefor, the leading end of said rope as viewed in the rotation of said drum in one direction causing the corresponding portion of said spring means to be operative, and stop means on said support for being abutted upon by the portion of said spring means cooperating with the trailing end of said rope as viewed in the rotation of said drum in the same direction to thereby cause the last said spring portion to be inoperative, the change-over of the direction of rotation of said drum serving to automatically render one of said spring portions operative and render the other spring portion inoperative.
  • each of the cylindrical body and drum is a part of a pulley which receives the input force of the clutch while the support for each of the frictional slider and the rope is drivingly connected to the output shaft of the clutch.
  • the frictional slider of the clutch according to the first aspect of the invention may preferably be made of a material having a remarkably small stiffness and large taff and wear-resistant properties, such as rope of fibrous material, thread and belt.
  • the rope of the clutch according to the second aspect of the present invention may preferably have similar properties.
  • the spring means in the clutch according to the second aspect of the invention may preferably be a twisted spring because a spring of this type can have its free ends or arms each of which is positioned substantially in the same radial plane as the corresponding free end of the rope extending from the spirally wound turns around the cylindrical drum.
  • the torque-transmission characteristic of the slipclutch depends solely upon the coefficient of friction between the sliding surfaces of the cylindrical body or drumand the frictional slider or rope and upon the angle over which the slider or the rope extends around the outer surface of the cylindrical body or drum.
  • the coefficient of friction and the angle in question can easily be determined to be of appropriate values so as to obtain a desired torque-transmission characteristic of the clutch.
  • the characteristic concerned is made stable and is not influenced with any kind of variation in friction coefficient between the sliding surfaces of the driving and driven members.
  • the maximum torque transmitted by the clutch according to the present invention is determined by the resiliency of the spring means used to connect the slider or rope to the support therefor.
  • FIG. 1 is an axial sectional side view of conventional slip-clutch mounted in a tape windingup mechanism of a tape recording and reproducing apparatus;
  • FIG. 2 is a similar sectional view of an embodiment of the slip-clutch according to the present invention which is mounted in a similar tape winding-up mechanism of a tape recording and reproducing apparatus;
  • FIG. 3 is a cross-section taken along line IlI--III in FIG. 2 and illustrating a cylindrical driving body, a frictionally driven slider and a support therefor;
  • FIG. 4 is a view similar to FIG. 3 but illustrates a modification to the clutch shown in FIGS. 2 and 3;
  • FIG. 5 is an axial sectional side view of another embodiment of the slip-clutch according to the present invention which is mounted in a tape winding-up mechanism of a different tape recording and reproducing apparatus;
  • FIG. 6 is a side view of the clutch of the instant embodiment with a part removed;
  • FIG. 7 is a cross-section taken along line VII-Vll in FIG. 5 and illustrating the relative position of a cylindrical drum, a rope, a spring, a support for the rope and a pair of stops on the support when the latter is rotated in one direction;
  • FIG. 8 is a view similar to FIG. 7 but illustrates the relative position of the elements when the support is rotated in the other direction; 1 1
  • FIG. 9 is a view similar to FIGS. 7 and 8 but illustrates a modification to the clutch shown in FIGS. 5 to 8;
  • FIG. 10 is a graphical representation illustrating the stability of the torque-transmission characteristic of the clutch of the invention with respect to the variation in the coefficient of friction between two cooperating friction members of the' clutch and a comparable characteristic of a prior art clutch with respect to similar variation in the friction coefficient.
  • the conventional clutch is illustrated as being mounted in a tape winding-up mechanism of a tape recording and reproducing apparatus having a reel supporting and driving wheel I mounted on a shaft 2 for free rotation.
  • a tire of rubber 3 is secured to the peripheral surface of the wheel 1.
  • the wheel 1 is so disposed as to be driven by a wheel or roll 4 which is in frictional rolling contact with the tire 3.
  • the roll 4 is rigidly mounted on one end of a shaft 5 which is rotatably supported by a bearing 6 which also serves to support a slip-clutch which is described hereafter.
  • the clutch includes a pulley 7 mounted for free rotation on a hub 10 of a disc 9 which in turn is rigidly secured to the other end of the shaft 5.
  • a disc of felt 8 is disposed between the disc 9 and the pulley 7 and is secured to the disc 9 for rotation therewith.
  • a spring retainer or washer 11 is mounted for free rotation on the shaft 5 adjacent the end of the bearing 6 remote from the roll 4.
  • a coil spring 12 is mounted around the shaft 5 and extends between the washer 11 and the pulley 7 so that the spring 12 resiliently urges the pulley 7 against the felt disc 8 with a substantially constant pressure force.
  • the pulley 7 is driven by means of a belt 13.
  • FIGS. 2 to 5 of the drawings illustrate an embodiment of the present invention.
  • the slip-clutch according to the instant embodiment of the invention includes a pulley 14 having a cylindrical outer surface 15.
  • the pulley 14 is mounted for free rotation on a shaft 5 for driving a reel supporting and driving wheel 1 in the same manner as that in the conventional device.
  • a frictional slider 16 is mounted on a support 17 in such a manner that a part of the slider 16 extends around a part of the cylindrical outer surface 15 of the pulley 14 in frictional sliding engagement with the surface 15 as will be best seen in FIG. 3.
  • the pulley 14 is rotated in clockwise direction, as indicated by the arrow draw within the circle of the outer surface 15 in FIG. 3.
  • the leading end of the frictional slider 16 as viewed in the rotation of the pulley 14 is connected to a spring 20 which in turn is secured to the support 17 as at 21.
  • the trailing end of the slider 16 is directly secured to the support 17 as at 19.
  • the support 17 has thereon a hub 18 which is rigidly secured to the shaft 5.
  • the frictional slider 16 is preferably made of a material having a remarkably small stiffness and good tensile and wear-resistant properties, such as rope of fibrous material, thread and belt.
  • FIG. 4 illustrates a modification to the slip-clutch shown in FIGS. 2 and 3.
  • a frictional slider 16 has spiral turns wound around the outer surface 15 of the pulley 14 so that the slider extends around the surface 15 over an angle of more than 360.
  • the instant embodiment is directed to a bi-directional slip-clutch which is used as a torque transmission in a tape winding-up mechanism for a tape recording and reproducing apparatus.
  • the tape winding-up mechanism includes a pair of laterally spaced reel supporting and driving wheels 31 and 32 having tires 33 and 34 mounted on the peripheral surfaces of the wheels, respectively.
  • a pulley or roll 35 is mounted on one end of a shaft 36 and is positioned to extend between the wheels 31 and 32
  • the shaft 36 rotatably extends through a bearing 37 mounted on a support 38 which is movably mounted so that the roll 35 can be selectively moved into frictional rolling contact with one of the tires 33 and 34 of the reel driving wheels 31 and 32 so as to drive the selected wheel for the take-up of the tape.
  • the slip-clutch of the instant embodiment of the invention is mounted on the other end of the shaft 36 and comprises a pulley 39 mounted for free rotation on the shaft 36.
  • the pulley 39 receives the input force of the clutch from a belt 40 which is in driving engagement with the pulley.
  • the latter has a hub or cylindrical drum 41 on the side of the pulley 39 remote from the bearing 37.
  • a length of rope 42 is spirally wound around the drum portion 41 and extends therearound in frictional sliding engagement therewith.
  • the material from which the rope 42 is made shouldbe determined depending upon the material from which the drum 41 is made.
  • the rope 42 is preferably made from a soft fibrous material in the case where the drum 41 is made from either a plastic material or a metal.
  • a disc 43 is rigidly connected to a hub 44 which in turn is fixed to the end extremity of the shaft 36 by means of a setscrew 45.
  • the disc 43 On the surface of the disc 43 facing the pulley 39, the disc 43 has a pin 47 extending axially toward the pulley 39 in spaced relationship to the drum 41.
  • the pin 47 rotatably receives coiled turns of a spirally twisted spring 46 having opposite free ends or arms 48 and 49 each connected to one of the ends of the rope 42 extending from the spiral turns thereof, as shown in FIG. 7, so that the twisted spring 46 is rotatably or swingably mounted on the disc 43.
  • the arms 48 and 49 have substantially the same length. Stop pins 52 and 53 are also mounted on the same side of the disc 43 as the pin 47 and adjacent the end extremities of the spring arms 48 and 49, respectively, for the purpose which will become apparent later.
  • the spring employed in the slipclutch according to the present invention has as smaller spring constant as possible in that a spring having such property exhibits lesser variation in spring force as caused by the deformation of the spring.
  • a twisted spring is satisfactory to this purpose.
  • the use of a twisted spring in this invention provides an additional advantage that the axial spacing between the opposite ends or arms of a twisted spring can accommodate the axial spacing between the ends of the rope spirally wound around the drum, so that it is possible to simplify the arrangement for holding the spring.
  • each of the spring arms 48 and 49 (48a and 49a in case of FIG. 9 embodiment) is positioned to extend substantially in the same radial plane as the corresponding end of the rope 42.
  • the same magnitude of torque is transmitted by the slip-clutch which employs spring arms 48 and 49 of the same length, as shown in FIGS. 7 and 8.
  • FIG. 9 illustrates a modification to the embodiment shown in FIGS. 5 to 8.
  • the clutch employs a spring 46a having arms 48a and 490 one (48a) of which is longer than the other (49a). The difference in the length of the spring arms causes the clutch to transmit a greater magnitude of torque in one direction of rotation of the clutch than in the other direction of rotation thereof.
  • the pulleys are disposed on input side of the clutch while the frictional slider and the rope are on the output side of the clutch. It is, however, to be noted that the same result can be obtained from the reversed relationship between the cooperating components of each clutch.
  • the ends of the rope 42 are shown as being directly connected to the spring arms 48 and 49 (48a and 49a in the case of FIG. 9 embodiment). It is, however, to be understood that additional fittings or joints can of course be utilized to connect the rope ends to the spring arms.
  • FIG. 10 graphically illustrates the relationship between the two variables. It will be appreciated from FIG. 10 that, when appropriate values are selected for the angle 0 and the friction coefficient [1-, a torquetransmission characteristic which is kept stable or substantially constant throughout prolonged operation is obtainable from the slip-clutch of the present invention even if the friction coefficient p. is varied during operation. It will further be understood that the slip-clutch of the invention provides remarkably improved stability in torque-transmission characteristic particularly with respect to the increase in the friction coefficient.
  • a curve indicated by 41r represents the torquetransmission characteristic of the clutch of the invention in the case where the slider 16 or rope 42 is wound around the cylindrical outer surface 15 or drum 41 over an angle of 471-, as in the embodiments shown in Fig. 4 and Figs.
  • This curve represents a very stable or constant torque-transmission characteristic in the range rightward of a point P at which friction coefficient p. is equal to 0.3, that is, in the range wherein p. is increased and is more than 0.3.
  • a conventional disc type slip-clutch which is designed to have its coefficient of friction p. on the point P provides a torque-transmission characteristic as represented by a curve A which extends substantially linearly in proportion to the value of t.
  • the present invention provides a slip-clutch whose torque-transmission characteristic is scarcely influenced by the variation in the coefficient of friction between two cooperating driving and driven members but is kept substantially constant and stable throughout the operation for prolonged period of time.
  • a bi-directional slip-clutch including a torquetransmission means comprising a cylindrical drum member and a length of a rope having spiral turns extending around said drum in frictional sliding engagement therewith, spring means for resiliently connecting the opposite free ends of said rope to a support therefor, the leading end of said rope as viewed in the rotation of said drum in one direction causing the corresponding portion of said spring means to be operative, and stop means on said support for being abutted upon by the portion of said spring means cooperating with the trailing end of said rope as viewed in the rotation of said drum in the same direction to thereby cause the last said spring portion to be inoperative, the torquetransmission means comprising a cylindrical drum member and a length of a rope having spiral turns extending around said drum in frictional sliding engagement therewith, spring means for resiliently connecting the opposite free ends of said rope to a support therefor, the leading end of said rope as viewed in the rotation of said drum in one direction causing the corresponding portion of said spring means to be operative, and stop means on said support for being

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mechanical Operated Clutches (AREA)
  • Friction Gearing (AREA)
US70036A 1969-09-10 1970-09-08 Slip-clutch Expired - Lifetime US3691791A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP7308969 1969-09-10
JP45007928A JPS5031807B1 (enrdf_load_stackoverflow) 1970-01-27 1970-01-27

Publications (1)

Publication Number Publication Date
US3691791A true US3691791A (en) 1972-09-19

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ID=26342326

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Application Number Title Priority Date Filing Date
US70036A Expired - Lifetime US3691791A (en) 1969-09-10 1970-09-08 Slip-clutch

Country Status (5)

Country Link
US (1) US3691791A (enrdf_load_stackoverflow)
BE (1) BE755933A (enrdf_load_stackoverflow)
FR (1) FR2061162A5 (enrdf_load_stackoverflow)
GB (1) GB1319125A (enrdf_load_stackoverflow)
NL (1) NL144038B (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4106583A (en) * 1976-08-25 1978-08-15 P. N. Associates, Inc. Self-powered folding golf cart
US20050126960A1 (en) * 2001-12-19 2005-06-16 Aas Per C. Apparatus method and system for receiving and distributing coins and notes
US20050184185A1 (en) * 2004-02-19 2005-08-25 Trw Automotive Gmbh Friction coupling

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2747592A1 (de) * 1977-10-24 1979-04-26 Keiper Automobiltechnik Gmbh Verstellbarer, insbesondere in einem fahrzeug, vorzugsweise kraftwagen, anzuordnender sitz
FR2531762B1 (fr) * 1982-08-13 1986-11-07 Valeo Dispositif amortisseur de torsion, notamment friction d'embrayage pour vehicule automobile

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4106583A (en) * 1976-08-25 1978-08-15 P. N. Associates, Inc. Self-powered folding golf cart
US20050126960A1 (en) * 2001-12-19 2005-06-16 Aas Per C. Apparatus method and system for receiving and distributing coins and notes
US20050184185A1 (en) * 2004-02-19 2005-08-25 Trw Automotive Gmbh Friction coupling
US20110056789A1 (en) * 2004-02-19 2011-03-10 Trw Automotive Gmbh Friction coupling
US8561932B2 (en) 2004-02-19 2013-10-22 Trw Automotive Gmbh Friction coupling for a reversible belt tensioner

Also Published As

Publication number Publication date
DE2044716A1 (de) 1972-01-27
BE755933A (fr) 1971-02-15
DE2044716B2 (de) 1972-07-13
NL144038B (nl) 1974-11-15
FR2061162A5 (enrdf_load_stackoverflow) 1971-06-18
NL7013316A (enrdf_load_stackoverflow) 1971-03-12
GB1319125A (en) 1973-06-06

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