US3730162A

US3730162A - Recoil starter

Info

Publication number: US3730162A
Application number: US00120979A
Authority: US
Inventors: K Murase
Original assignee: Starting Industrial Co Ltd
Current assignee: Starting Industrial Co Ltd
Priority date: 1971-03-04
Filing date: 1971-03-04
Publication date: 1973-05-01
Anticipated expiration: 1990-05-01

Abstract

A recoil starter wherein the driving ratchet is maintained in a retracted inoperative position during the operation of the engine.

Description

' [22] Filed:

United States Patent 1 Murase [73] Assignee: Starting Industrial Co., Ltd., Tokyo,

Japan Mar. 4, 1971 [21] Appl. No.: 120,979

52 us. c1 ..123/1ss BA 51 1.11.121 .....F02n 3/02 [58] Field of Search 123/185 A, 185 B, 123/185 BA, 185 R, 179 SE; 192/42, 71

[56] References Cited UNITED sTATEs PATENTS 2,692,589 10/1954 Watkins .,...l23/l85 BA 2,709,994 6/1955 Chandler 123/185 BA 1111 3,730,162 51 May 1,1973

FOREIGN PATENTS 0 APPLICATIONS 816,257 7/1959 Great Britain ..123/185 BA Primary Examiner-A1 Lawrence Smith Attorney-William .1. Daniel [5 7] ABSTRACT operation of the engine.

3 Claims, 4 Drawing Figures RECOIL STARTER This invention relates to recoil starters.

Conventional recoil starters used for agricultural machines, domestic lawnmower-s, snow plows and other gasoline engine powered lawn and garden equipment are so complicated in the design that they are likely to have structural defects, their production cost is high and the starting ratchet often becomes engaged during operation because of vibration.

On the other hand, if the starting ratchet includes a cam surface which is engaged when the engine is operating and overdriving the ratchet drive in order to hold the ratchet retracted, then the continuous engagement of the cam surface reduces its useful life considerably.

The present invention has the object of providing a recoil starter of simple design wherein the ratchet does not accidentally move into its operating position during the operation of the engine.

In the drawings:

FIG. 1 is a sectioned side view of a recoil starter according to the present invention;

FIG. 2 is a sectioned view on line II II in FIG. 1 of the recoil starter showing the ratchet connection in inoperative position.

FIG. 3 is a similar section view as in FIG. 2 but showing the ratchet connection in operative driving position;

FIG. 4 is a sectioned view on line IV IV in FIG. 2 of a twisted coil spring part.

In FIG. 1, a recoil starter l is formed of a coupling wheel 2 directly connected with the engine to be started, a frictionally-restrained, disc-shaped control arm or friction disc 3, a ratchet plate 4 processed, for

example, with a resin, a starting pulley 5, a recoil spring 6 and a housing 7. The wheel 2 is formed with a peripheral skirt or apron 8 extending in the axial direction, the apron being cutaway or interrupted at equal intervals to provide four notches 9. A hole 10 is made in the central part of the friction disc 3 and a hole 13 is made also in the central boss 11 of the housing 7. A bolt 14 is inserted through these

holes

10 and 13 to rotatably fasten the friction plate to the housing. A spring encircles bolt 14 in a recess 12 to bias the disc 3 against the head of bolt 14. While disc 3 is thus able to rotate about the bolt, it is frictionally engaged between spring 15 and the bolt head to resist such rotation.

The starting pulley 5 is journaled on the central boss 11 of housing 7 which serves as a stub shaft for rotatably supporting the pulley. The periphery of pulley 5 is formed with the usual V-groove in which is wound the pull cord 20, the outer end of cord extended outside housing 7 for easy access during starting. Recoil spring 6 is a spiral spring having its ends affixed to the starting pulley and housing respectively. When the pulley is rotated as cord 20 is pulled, spring 6 is tensioned to reversely rotate pulley 5 and rewind cord 20 when the cord is released.

In order to temporarily connect pulley 5 to engine coupling wheel 2, the ratchet plate 4 is mounted on the end face of pulley 5 opposite recoil spring 6 for limited pivotal movement around a post P provided on that face. Post P is spaced radially from the pulley axis and is thus eccentrically located relative to the pulley axis. Ratchet plate 4 has a generally semi-circular socket 18 for pivotally encircling post P and socket 18 opens into a central aperture 17 in the plate to receive the hub of friction disc 3. Aperture 17 is enlarged laterally at 17', i.e., in a direction generally perpendicularly of a radius passing through the. pulley axis and the axis of post P, in order to allow the limited pivotal movement of the ratchet plate.

At one point on the periphery of ratchet plate 4 is a ratchet tooth 19 having a leading shoulder edge for positive engagement with an edge of one of the notches 9 to drive coupling wheel 2 and an inclined trailing edge. When plate 4 is pivoted about post P in a clockwise direction, tooth 19 is moved to projected driving position in engagement with an edge of a notch 9. Pivotal movement of plate 4 in the opposite counterclockwise direction withdraws tooth 19 to a retracted non-driving position.

A torsion spring 22 is arranged in a central bore in post P with one of its ends 23 engaged in a seat formed in the ratchet plate as at 26 (see FIG. 4) while the other end is affixed to the pulley face. Spring 22 is tensioned to bias ratchet plate 4 to retract tooth 19 to its non-engaged inoperative position, as indicated by arrow B in FIG. 2.

A connection allowing limited relative rotational movement is maintained between ratchet plate 4 and friction disc3. Thus, an elongated aperture 16 is made in plate 4 generally opposite to pivot socket 18, the length b (FIG. 3) of aperture 16 being consistent with the extent of movement needed by plate 4. A pin 24 projects from the adjacent face of friction disc 3 into the opening of aperture 16 so that the frictional resistance to rotation of friction disc 3 is transmitted to ratchet plate 4. During starting, this resistance acts to resist the bodily rotational movement of the ratchet plate with starting pulley 5 as the pulley is rotated by the pull cord; hence, pin 24 causes plate 4 to pivot about post P in a clockwise direction, moving ratchet tooth 19 into operative driving position. Conversely, when the pulley rewinds, the resistance of the friction disc causes plate 4 to pivot counterclockwise, displacing tooth 19 to retracted inoperative: position.

In operating the recoil starter according to the present invention, when the cord 20 is first pulled by the operator, the pulley 5 moves in the direction indicated by the arrow A against the force of the spring 6. In such case, the ratchet 4 also rotates in the direction indicated by the arrow A. I-Iowever., dueto the pin 24 projecting into hole 16 in the ratchet plate 4, plate 4 pivots about post P the length b of the hole 16 and engages tooth 19 in one of the notches 9. When the cord 20 is further pulled, the wheel 2 now rotates with the starting pulley 5, starting the engine. When the cord is released, the ratchet tooth 19 of the ratchet plate is displaced to retracted position in the condition shown in FIG. 2.

In the above embodiment, the hole 16 is made in the ratchet plate 4. However, a notch having the same friction as the hole 16 may be made in the outside periphery of the ratchet plate or as an extension of the central hole 17 in plate 4.

As mentioned above, the recoil starter according to the present invention is always urged to its inoperative position shown in FIG. 2 after completion of the starting operation. Thus, the conventional defect that the ratchet tooth easily comes into contact with the engine coupling wheel is eliminated by the resistance applied by spring through disc 3 and pin 24 against ratchet plate 4 and the biasing force of torsion spring 22 urging the ratchet plate 4 continually to inoperative position, that is, in the direction indicated by the arrow B in FIG. 2.

What is claimed is:

l. A recoil starter for an engine comprising a supporting shaft, a pulley journaled for rotation on said shaft, a cord wound around said pulley and adapted to rotate said pulley when said cord is pulled, spring means tensioned when said pulley is rotated by said cord for rewinding the pulley and cord when the cord is released, a ratchet plate having a peripheral ratchet tooth and mounted on an end face of said pulley for limited pivotal movement about an axis disposed in eccentric relation to said shaft axis, said pivotal movement being between an operative position in which said ratchet tooth is radially projected and an inoperative position in which said ratchet tooth is retracted, spring means acting on said ratchet plate to bias the same to said inoperative position, a coupling wheel adapted to be connected to said engine for rotation therewith, said coupling wheel having a cylindrical apron extending in telescoped relation around said ratchet plate, said wheel apron having at least one notch therein for engagement by said ratchet tooth when the latter is in projected operative position, a ratchet plate control arm mounted on said shaft between said ratchet plate and said coupling wheel for independent rotation about said shaft, means frictionally engaging said control arm to resist rotation thereof, and means connecting said ratchet plate and control arm for rotation together, said connecting means permitting limited independent rotational movement of said plate and control arm corresponding to the travel of said plate between its inoperative and operative positions.

2. The recoil starter of claim 1 wherein said connecting means comprises an opening of predetermined arcuate extent on one of said plate and arm and a fixed projection in the other of said plate and arm extending into said opening.

3. The recoil starter of claim 1 wherein said ratchet plate encircles said supportingshaft and is provided with an enlarged central aperture permitting said plate to pivot between said inoperative and operative positions.

Claims

1. A recoil starter for an engine comprising a supporting shaft, a pulley journaled for rotation on said shAft, a cord wound around said pulley and adapted to rotate said pulley when said cord is pulled, spring means tensioned when said pulley is rotated by said cord for rewinding the pulley and cord when the cord is released, a ratchet plate having a peripheral ratchet tooth and mounted on an end face of said pulley for limited pivotal movement about an axis disposed in eccentric relation to said shaft axis, said pivotal movement being between an operative position in which said ratchet tooth is radially projected and an inoperative position in which said ratchet tooth is retracted, spring means acting on said ratchet plate to bias the same to said inoperative position, a coupling wheel adapted to be connected to said engine for rotation therewith, said coupling wheel having a cylindrical apron extending in telescoped relation around said ratchet plate, said wheel apron having at least one notch therein for engagement by said ratchet tooth when the latter is in projected operative position, a ratchet plate control arm mounted on said shaft between said ratchet plate and said coupling wheel for independent rotation about said shaft, means frictionally engaging said control arm to resist rotation thereof, and means connecting said ratchet plate and control arm for rotation together, said connecting means permitting limited independent rotational movement of said plate and control arm corresponding to the travel of said plate between its inoperative and operative positions.

3. The recoil starter of claim 1 wherein said ratchet plate encircles said supporting shaft and is provided with an enlarged central aperture permitting said plate to pivot between said inoperative and operative positions.