US1720778A - Starting crank for internal-combustion engines - Google Patents

Description

A. BEAUBIEN July 16, 1929.

STARTING'CRANK FOR INTERNAL COMBUSTION ENGINES Filed April 18, 1928 INVENT'OR HLPHONSE BEAUB IEN RTTORNEYS Patented July 16, 1929.

UNITED STATES PATENT OFFICE.

STARTING CRANK FOR INTERNAL-COMBUSTION ENGINES.

Application filed April 18,

My invention relates to improvements in starting cranks for internal combustion engines, which are particularly adapted for use on tractors, motor boats and the like. The objects of the invention are to provide means whereby the reverse movement of the engine shaft due to back firing is not communicated to the handle of the starting crank.

The invention consists essentially of a shaft adapted to be fitted to the crank shaft of an engine, a hand crank for said shaft having a frictional grip interposed between them, whereby the rotation of the crank imparts corresponding rotation to the shaft until a predetermined resistance to rotation is encountered, as will be more fully described in the following specification, and shown in the accompanying drawings, in which Fig. 1 is a front view, partly in section, of the crank mechanism.

Fig. 2 is a section through the radiator of a tractor showing the starting crank fitted to the engine crank shaft.

Fig. 8 is a front View showing the crank and the annular rack with which it engages.

In the drawings like characters of refer-- ence indicate corresponding parts in each figure.

The numeral 1 indicates the forward end of an engine crank shaft having the usual dog clutch 2, which is adapted to be engaged by the starting crank. The numeral 3 indicates a radiator on the front of which is mounted an annular saw tooth rack 4 the purpose of which will hereinafter appear.

The numeral 5 indicates generally a start-- ing crank which is formed with a shaft 6 having at its free end a transverse pin 7 by which engagement is effected with the clutch 2 of the engine shaft 1. The shaft 6 is journalled between two plates forming a housing 8 and is fitted with an oval cam 9. Extending from v the housing 8 is a hand crank 10 and pivotally mounted therein as at 11 is a pair of opposed gripping levers 12 which are curved intermediate their length to conform to the sides 13 of the cam 9. The free ends of the levers 12 are eyed as at 14 and support a bolt 15 which is provided at one or both ends With butterfly nuts 16 for the purpose of forming abutments to one or more springs 17, which springs are so compressed as to hold the levers 12 in firm contact with the peripheral faces 1928. Serial No. 270,943.

of the cam 9. Mounted upon the underside of the housing 8 is a spring pressed pawl 18 which is adapted to engage the annular rack 4 to permit the crank 10 to rotate in a clockwise direction and to prevent its rotation in an opposite direction.

In operation the shaft 6 is engaged with the engine shaft 1 in the usual way and as the hand crank 10 is turned, the levers 12 are spread apart by partially turning about the cam 9 due to the resistance to rotation of the engine shaft substantially as shown in dotted line in Figure 1. As soon as the resistance afforded bv the springs 17 to the spreading apart of the lovers becomes greater than the resistance of the engine shaft to rotation, the cam 9 will be held stationary between the levers and the. continued rotational movement of the hand crank will be communicated through the shaft 6 to the engine shaft 1. If insufficient resistance is imposed to the rotation of the cam between the levers, the butterfly nuts 16 are tightened up upon the bolt 15 as may be required.

During the turning movement of the hand crank in a starting direction, the pawl 18 is being drawn along the teeth of the annular rack 4, but as soon as a back fire occurs the pawl engages one of the rack teeth, preventing the hand crank from being rotated in the opposite direction, simultaneously the engine shaft imparts rotation through the shaft (3 to the cam 9, causing the levers 12 to be thrown apart as the longer axis of said cam is moved to a position transverse to the levers and allowing them to move back to normal position as the shorter axis reaches a similar position relative to said levers. The lever movement thus described will continue so long as the engine is turning contrary to its normal running direction.

What I claim as my invention is:

1. A starting crank for internal combustion engines comprising a shaft adapted to be releasibly fitted to the shaft of the engine, said shaft being fitted with a cam and being journalled in a hand crank housing, a han dle to the housing and a spring tensioned means carried by the housing engaging the cam for imposing a resistance to the rotation of the shaft sufficient to overcome the resistance to rotation of the engine shaft.

2. A starting crank for internal combustion en 'ines comprising a shaft adapted to be releasably fitted to the shaft of the engine,

said shaft being fitted with a cam and being journalled in a hand crank housing, a handle to the housing and a spring tensioned lever curved to conform substantially to a portion of the cam and in engagement therewith whereby a resistance is imposed to the rotation of the shaft sutficient to overcome the resistance to rotation of the engine shaft.

Dated at Vancouver, B. O, this 5th day of April, 1928.

BEEN

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