US3059500A - Pawl and ratchet device - Google Patents

Pawl and ratchet device Download PDF

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Publication number
US3059500A
US3059500A US55015A US5501560A US3059500A US 3059500 A US3059500 A US 3059500A US 55015 A US55015 A US 55015A US 5501560 A US5501560 A US 5501560A US 3059500 A US3059500 A US 3059500A
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United States
Prior art keywords
pawl
blade
section
ratchet
wheel
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Expired - Lifetime
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US55015A
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Schneiter Ali
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Ebauches SA
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Ebauches SA
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    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B11/00—Click devices; Stop clicks; Clutches
    • G04B11/02—Devices allowing the motion of a rotatable part in only one direction
    • G04B11/04—Pawl constructions therefor, e.g. pawl secured to an oscillating member actuating a ratchet
    • G—PHYSICS
    • G04—HOROLOGY
    • G04B—MECHANICALLY-DRIVEN CLOCKS OR WATCHES; MECHANICAL PARTS OF CLOCKS OR WATCHES IN GENERAL; TIME PIECES USING THE POSITION OF THE SUN, MOON OR STARS
    • G04B11/00—Click devices; Stop clicks; Clutches
    • G04B11/02—Devices allowing the motion of a rotatable part in only one direction
    • G04B11/022—Devices allowing the motion of a rotatable part in only one direction with a ratchet which makes contact with the rotating member by means of teeth
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/15—Intermittent grip type mechanical movement
    • Y10T74/1526—Oscillation or reciprocation to intermittent unidirectional motion
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/21—Elements
    • Y10T74/2133—Pawls and ratchets

Definitions

  • PAWL AND RATCHET DEVICE Filed Sept. 9, 1960 Ayenls United States Patent 3,059,500
  • PAWL AND RATCHET DEVICE Ali Schneiter, Neuchatel, Switzerland, asignor to Ebauches S.A., Neuchatel, Switzerland, a firm Filed Sept. 9, 1960, Ser. No. 55,015 Claims priority, application Switzerland Sept. 12, 1961 6 Claims. (Cl. 74-575)
  • the present invention relates to pawl and ratchet devices notably fOI' retaining a leverescapement wheel.
  • Pawl and ratchet devices of the type utilising a resilient blade for a pawl are well known.
  • the blade engages the 'teeth of a ratchet Wheel and is adapted for preventing recoil of the wheel.
  • the blade In the design of the blade it is necessary to construct the same so that it is of saidcient rigidity to resist buckling when the recoil force of the wheel is applied thereto, while the blade must also be of suiiicient flexibility in order not to exert an excessive pressure on the teeth of the ratchet wheel to prevent norrmal rotation thereof.
  • the blades were either excessively flexible or rigid, depending on the use to which the blade was put.
  • a particular object of the invention is to provide a pawl and ratchet gear rod, which is able to resist without buckling substantial recoil forces of the wheel while exerting on the wheel pressure which is substantially unrelated to the strength of the rod necessary for resisting buckling.
  • the pawl and ratchet device is characterised by a bent rod or blade forming a pawl, and is supported at one of its ends and co-operates at its other end with a ratchet, the rod or blade also bearing, adjacent the bend thereof, against an abutment, the arrangement being such that the resilience of the pawl is furnished by the resistance to torsion of the section of the rod or blade which extends between the point of attachment and the bend.
  • the resilience is independent of the resistance of the pawl to buckling, which resistance is inter alia a function of the length of the section of the rod or blade which extends between the bend and the end co-operating with the ratchet.
  • FIGURE 1 is a plan view of a wheel and a lever of an escapement, the wheel being retained 'by the pawl and ratchet device according to the invention
  • FIGURE 2 is an elevational view of the structure in FIG. 1 shown in section.
  • Lever 1 has pallets 2 which co-operate with an escape wheel 3 having on its lower face teeth 3a extending therefrom.
  • a section 4a of a resilient blade is adapted to cooperate with the teeth in a manner to be explained more fully hereinafter.
  • the resilient blade has a second section 4b which is fixed at its end to an eye bolt 5, which is in turn mounted on a bridge 6 of the frame of the apparatus on which the device is mounted.
  • the two sections 4a and 4b of the resilient blade are in skewed relation with respect to one another, for which purpose the blade has been twisted at 40.
  • the sections extend perpendicularly to one another by virtue of a right angle bed at 4d.
  • An eccentric 7 bears against the section 4b of the blade, adjacent bend 4d.
  • the pawl consisting of the resilient blade is operating by virtue of torsion of Patented Oct. 23, 1962 section 4b.
  • the force with which the pawl acts on the ratchet 3a is mainly a function of the length of the section 4b since the angle of twist at the end of section 4b adjacent bend 4d is substantially proportional to the length of section 4b.
  • the retaining force of the pawl i.e. its resistance to buckling, is determined mainly by the length of the section 4a of the blade.
  • the section 4a of the resilient blade is slightly displaced, by a slight bending of section 41), whereby it is possible to very accurately adjust the angular position of the wheel 3 when the same is stationary and in contact with the retaining paw-l.
  • the pawl and ratchet gear which has many applications, will be particularly suitable for retaining escape wheels of lever escapements, these wheels often tending to recoil, since they are not urged to turn in a particular direction, as are ordinary escape wheels.
  • a pawl for use with a ratchet wheel comprising an elongated blade including first and second ends, said blade including a bend dividing said blade into a first straight section which includes sa-id first end and a second straight section which includes said second end, means for rigidly supporting said first end, an abutment in contact with the first section adjacent said bend, and a twist in said second section adjacent said bend for urging said second end into operative contact with said ratchet wheel whereby the resilience of said pawl is provided by said first section and the buckling resistance of said pawl is provided by said second section.
  • Apparatus comprising: an escape wheel including a face and teeth extending from said face; means for pivotally mounting said escape wheel in a given plane; and a pawl including an elongated blade including first and second ends and sides, said blade having a bend dividing said blade into a first straight section which includes said first end and a second straight section which includes said second end; means for rigidly supporting said first end so that said first section is disposed in a plane parallel to and displaced from said given plane; an abutment in contact with the first section of said blade remote from said second end; and a twist in said second section whereby said second end is urged against the teeth of said escape wheel.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Scissors And Nippers (AREA)

Description

O 3, 1 2 A. SCHNEITER 3,059,500
PAWL AND RATCHET DEVICE Filed Sept. 9, 1960 Ayenls United States Patent 3,059,500 PAWL AND RATCHET DEVICE Ali Schneiter, Neuchatel, Switzerland, asignor to Ebauches S.A., Neuchatel, Switzerland, a firm Filed Sept. 9, 1960, Ser. No. 55,015 Claims priority, application Switzerland Sept. 12, 1959 6 Claims. (Cl. 74-575) The present invention relates to pawl and ratchet devices notably fOI' retaining a leverescapement wheel.
Pawl and ratchet devices of the type utilising a resilient blade for a pawl are well known. The blade engages the 'teeth of a ratchet Wheel and is adapted for preventing recoil of the wheel. In the design of the blade it is necessary to construct the same so that it is of saidcient rigidity to resist buckling when the recoil force of the wheel is applied thereto, while the blade must also be of suiiicient flexibility in order not to exert an excessive pressure on the teeth of the ratchet wheel to prevent norrmal rotation thereof. Heretofore, the blades were either excessively flexible or rigid, depending on the use to which the blade was put.
It is an object of the present invention to obviate the above disadvantage by providing a pawl and ratchet gear in which the buckling strength and the flexibility of the blade are substantially independent of one another, so that the blade can be made suitably rigid while exhibiting desired flexibility. A particular object of the invention is to provide a pawl and ratchet gear rod, which is able to resist without buckling substantial recoil forces of the wheel while exerting on the wheel pressure which is substantially unrelated to the strength of the rod necessary for resisting buckling.
The pawl and ratchet device is characterised by a bent rod or blade forming a pawl, and is supported at one of its ends and co-operates at its other end with a ratchet, the rod or blade also bearing, adjacent the bend thereof, against an abutment, the arrangement being such that the resilience of the pawl is furnished by the resistance to torsion of the section of the rod or blade which extends between the point of attachment and the bend. The resilience is independent of the resistance of the pawl to buckling, which resistance is inter alia a function of the length of the section of the rod or blade which extends between the bend and the end co-operating with the ratchet.
A preferred embodiment of the subject of the invent-ion is illustrated by way of example in the accompanying drawings.
FIGURE 1 is a plan view of a wheel and a lever of an escapement, the wheel being retained 'by the pawl and ratchet device according to the invention, and
FIGURE 2 is an elevational view of the structure in FIG. 1 shown in section.
Lever 1 has pallets 2 which co-operate with an escape wheel 3 having on its lower face teeth 3a extending therefrom. A section 4a of a resilient blade is adapted to cooperate with the teeth in a manner to be explained more fully hereinafter. The resilient blade has a second section 4b which is fixed at its end to an eye bolt 5, which is in turn mounted on a bridge 6 of the frame of the apparatus on which the device is mounted. The two sections 4a and 4b of the resilient blade are in skewed relation with respect to one another, for which purpose the blade has been twisted at 40. In addition the sections extend perpendicularly to one another by virtue of a right angle bed at 4d. An eccentric 7 bears against the section 4b of the blade, adjacent bend 4d.
Because of the above arrangement, the pawl consisting of the resilient blade is operating by virtue of torsion of Patented Oct. 23, 1962 section 4b. The force with which the pawl acts on the ratchet 3a is mainly a function of the length of the section 4b since the angle of twist at the end of section 4b adjacent bend 4d is substantially proportional to the length of section 4b. On the other hand, the retaining force of the pawl i.e. its resistance to buckling, is determined mainly by the length of the section 4a of the blade. Thus, by choosing suitable relative lengths of sections 4a and 4b, it is possible to establish, in accordance with requirements, the ratio between the retaining force of the pawl and ratchet gear and the pressure with which the pawl acts on the ratchet.
By turning the eccentric 7, the section 4a of the resilient blade is slightly displaced, by a slight bending of section 41), whereby it is possible to very accurately adjust the angular position of the wheel 3 when the same is stationary and in contact with the retaining paw-l.
The pawl and ratchet gear, which has many applications, will be particularly suitable for retaining escape wheels of lever escapements, these wheels often tending to recoil, since they are not urged to turn in a particular direction, as are ordinary escape wheels.
While only one embodiment of the invention has been shown and described in detail, it will be apparent to those skilled in the art that modifications such as different crosssections for the blade are possible which do not depart from the spirit of the invention as defined in the appended claims.
What I claim is:
l. A pawl for use with a ratchet wheel comprising an elongated blade including first and second ends, said blade including a bend dividing said blade into a first straight section which includes sa-id first end and a second straight section which includes said second end, means for rigidly supporting said first end, an abutment in contact with the first section adjacent said bend, and a twist in said second section adjacent said bend for urging said second end into operative contact with said ratchet wheel whereby the resilience of said pawl is provided by said first section and the buckling resistance of said pawl is provided by said second section.
2. The pawl of claim 1 wherein said abutment is positioned on the side of said first sec-tion remote from said second end.
3. Apparatus comprising: an escape wheel including a face and teeth extending from said face; means for pivotally mounting said escape wheel in a given plane; and a pawl including an elongated blade including first and second ends and sides, said blade having a bend dividing said blade into a first straight section which includes said first end and a second straight section which includes said second end; means for rigidly supporting said first end so that said first section is disposed in a plane parallel to and displaced from said given plane; an abutment in contact with the first section of said blade remote from said second end; and a twist in said second section whereby said second end is urged against the teeth of said escape wheel.
4. A pawl as claimed in claim 1, in which the position of the said abutment is adjustable.
5. A pawl as claimed in claim 1, in which the said abutment includes an eccentric.
6. A pawl as claimed in claim 1, in which said bend is about .Ensign et al. Aug. 7, 1956 Rodgers et a1. July 14, 1959
US55015A 1959-09-12 1960-09-09 Pawl and ratchet device Expired - Lifetime US3059500A (en)

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3670493A (en) * 1970-03-27 1972-06-20 Timex Corp Indexing mechanism for electric/electronic timepieces
US3685279A (en) * 1971-07-15 1972-08-22 Ivnghans Gmbh Fa Geb Continuous switching device for the gear mechanism of an electric wrist watch
US3783608A (en) * 1971-02-17 1974-01-08 Suwa Seikosha Kk Indexing device for a step motor in an electronic timepiece
US4762971A (en) * 1984-04-23 1988-08-09 Mitsubishi Denki Kabushiki Kaisha Spring-type operating mechanism for a circuit interrupter
US5180262A (en) * 1991-05-28 1993-01-19 Westerdale Norman R Adjustable chain vehicle tie-down apparatus
US5676354A (en) * 1995-07-14 1997-10-14 Fuji Photo Film Co., Ltd. Sheet film pack
US6019198A (en) * 1997-12-09 2000-02-01 Preo New Products Corp. Mechanically driven ratchet assembly
USD819896S1 (en) * 2017-08-21 2018-06-05 Avian Cafe Corporation Aves cafe
USD836851S1 (en) 2017-12-18 2018-12-25 Avian Corporation Aves cafe

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2757545A (en) * 1953-08-04 1956-08-07 Elgin Nat Watch Co Power take-off device, particularly for timepieces
US2895026A (en) * 1957-04-26 1959-07-14 Gen Motors Corp Switch operating means

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2757545A (en) * 1953-08-04 1956-08-07 Elgin Nat Watch Co Power take-off device, particularly for timepieces
US2895026A (en) * 1957-04-26 1959-07-14 Gen Motors Corp Switch operating means

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3670493A (en) * 1970-03-27 1972-06-20 Timex Corp Indexing mechanism for electric/electronic timepieces
US3783608A (en) * 1971-02-17 1974-01-08 Suwa Seikosha Kk Indexing device for a step motor in an electronic timepiece
US3685279A (en) * 1971-07-15 1972-08-22 Ivnghans Gmbh Fa Geb Continuous switching device for the gear mechanism of an electric wrist watch
US4762971A (en) * 1984-04-23 1988-08-09 Mitsubishi Denki Kabushiki Kaisha Spring-type operating mechanism for a circuit interrupter
US5180262A (en) * 1991-05-28 1993-01-19 Westerdale Norman R Adjustable chain vehicle tie-down apparatus
US5676354A (en) * 1995-07-14 1997-10-14 Fuji Photo Film Co., Ltd. Sheet film pack
US6019198A (en) * 1997-12-09 2000-02-01 Preo New Products Corp. Mechanically driven ratchet assembly
USD819896S1 (en) * 2017-08-21 2018-06-05 Avian Cafe Corporation Aves cafe
USD836851S1 (en) 2017-12-18 2018-12-25 Avian Corporation Aves cafe

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