US1288708A - Starting-crank safety device for motor-vehicles. - Google Patents

Description

L. c. SHARP.

STARTING CRANK SAFETY DEVICE FOR MOTOR VEHlCLES. 7

APPLICATION FILED 1AN.'21, I911.

\ 1,288,708.. Patent-ed Dec. 24, 1918.

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LEE 0. SHARP, OF PLATTSMOUTH, NEBRASKA.

STARTINGVCRANK SAFETY DEVICE FOR MOTOR-VEHICLES.

Specification of Letters Patent.

Patented Dec. 24:, 1918.

Application filed January 27, 1917. Serial No. 145,015.

To all whom it may concern:

Be it known that I, LEE C. SHARP, a citizen of the United States, and a resident of Plattsmouth, in the county of Cass and State of Nebraska, have invented certain new and 'useful Improvements in Starting-Crank Safety Devices for Motor-Vehicles, of which the following is a specification.

My invention relates to motor vehicles propelled by internal combustion engines, and particularly to starting-cranks for such engines. It is the object of my invention to provide a simple, inexpensive and easilyinstalled safety-device for preventing reverse movement of the starting-crank due to backfiring or premature ignition of a charge when starting a motor-vehicle engine by hand. Backfiring of internal combustion engines during the starting thereof occurs very frequently and usually results from premature ignition, due to incorrect adjustment or too great advance of the ignition-timing devices, although also resulting occasionally from other causes such that the improper operation can not be prevented even by the exercise of special care on the part of the operator. When starting an engine by hand-cranking thereof, backfiring often results in serious injury to the person holding the crank, the latter being forcibly pulled from the hand and making one or more reverse revolutions during which the person may be struck thereby, and frequently bones of the hand, arm or jaw are broken, and even deaths are sometimes caused by this means. My invention pro vides a positive and reliable means for the prevention of such accidents.

In the accompanying drawings Figure 1 is a front elevation of devices embodying my invention, parts thereof being in section on the plane of the line 11 of Fig. 2, and Fig. 2 is a longitudinal vertical section of the same on the line 2-2 of Fig. 1.

The illustrated embodiment of my invention is especially designed for use on the well-known Ford motor-vehicles, and there are shown in the drawings the related parts of such a vehicle necessary to illustrate the connection of my safety device there with. Thus, there is shown in Fig. 2 the front end-portion of the engine crank-case,

said part 3 having secured thereto a bearingmember 4: which rests in a seat or pillo wblock 5, and the latter resting upon the central portion of the front cross-member 6 of the vehicle-frame, as shown in Fig. 1. The radiator 7 is disposed above the cross-member 6, being in spaced relation to the central part thereof, and said central part of the crossmember rests upon the front spring 8, being secured thereto by means of U-bolts 9 of which the upper ends pass through projecting lugs 10 on the base-portion of the pillow-block 5. The bearing-member 4 has a longitudinal bore or opening in which there is permanently secured a sleeve 11, the latter being in axial alinement with the engine crank-shaft 12. The front end-portion of the crank-shaft has the usual cross-pin 13 for engagement by the head of the startingcrank. All of the foregoing parts are of the construction and arrangement usually found in vehicles of the class mentioned. The head 14: of the starting-crank is also of the usual form and comprises a cup-shaped body, adapted to pass loosely over the end of the crank-shaft 12, and having in the end thereof helically-extending notches forming ratchet-like teeth for engagement with the pin 13.

The head 14c is carried on the rear end of a shaft 15 which fits revolubly and slidably in the bore of the sleeve ll,the head being secured to the shaft by means of a pin 16. The

front end-portion of the shaft 16 projects be yond the bearing therefor in the sleeve 11 and carries the hand-crank 17 of which the hub-portion 18 is secured to the shaft by a pin 19. On the rear end of the hub 18 and integral therewith is a ratchet-wheel 20 of which the end is counterbored to receive a portion of a coil spring 21 disposed around the shaft in front of the bearing-sleeve 11. Said spring 21 holds the shaft 15 normally in the position shown in Fig. 2, at which the end of the head 14: engages the rear end of the sleeve 11, but by compression of the spring the shaft may be moved rearwardly to a position at which the head will pass over the end of the crank-shaft 12 and engage the cross-pin 18 thereon. When the shaft is in the latter position, the ratchet wheel 20 is in proximity to the front end of the bearing-member 4, and most of the spring 21 lies within the counterbore of the end of the ratchet-wheel. In front of the frame cross-member 6 there is disposed-a stop-supporting bracket having laterally extending lugs 22 which rest upon the lugs 10 of the pillow-block 5, the ends of the U- bolts 9 passing through said lugs 22, and the latter being clamped against the lugs 10 by nuts 23 screwed on the threaded upper portions 'of the U-bolts. Said stop-supporting bracket has an annular central portion 24 disposed concentrically with the shaft 15, and at the lower side of said annular portion there is a tubular depending socket 25. Within the bore of the socket 25 a cylindrical pawl-stem 26 fits slidably, the upper end of said stem having at one side a fiat face 27 adapted to engage the radial portions of the teeth on the ratchet-wheel 20. A pin 28 extends horizontally through the stem 26, the ends of said pin fitting slidably in vertical slots 29 in the sides of the socket 25. The lower end of the stem 26 has a cylindrical recess therein, and in said recess is disposed the upper portion of a coil spring 30 of which the lower end rests on the bottom of the socket 25. At the upper end of the recess in the stem there is a threaded opening for receiving the end of a screw 31, which passes down through the spring and the bottom of the socket, having at its lower end a head between which and the bottom of the socket are disposed washers 32 and 33. The washer 33 is of leather or like yieldable material, and forms a cushioning stop for limiting upward movement of the screw and stem 26. The length of the stop-screw 31 is so proportioned that at the limit of upward movement of the pawlstem 26 the upper end thereof will be in approximately the relation to the ratchetwheel 20 shown in Fig. 1, in which there is a slight clearance between the end of the stem and the adjacent tangential tooth-face of the wheel. Thus, when the shaft 15 is in the forward position shown in Fig. 2, the pawl-stem cannot move up far enough to interfere with the rearward movement of the ratchet-wheel, if the latter be turned so that the pawl-stem is alined with one of the notches between the ratchet-teeth. It will be noted that the relation of the parts longitudinally of the shaft-axis is such that the wheel 20 and pawl-stem 26 are in en gaging relation to each other whenever the head 14: is in position to engage the crosspin 13 of the engine crank-shaft, and that when the shaft 15 is moved forwardly the ratchet-wheel 20 is disengaged from the pawl-stem subsequently to the disengagement of the head 14 from the cross-pin 13.

When starting the engine, the hand-crank is manipulated in the usual manner, the same being pushed rearwardly far enough to engage the crank-shaft 12 and the latter being turned thereby as required to cause the suction, compression and ignition of one or more charges in the engine cylinders. The

engagement of the pawl-stem 26 with the ratchet-wheel 20 effectively prevents movement of the starting-crank except in the normal direction of rotation of the engineshaft, and, should the engine backfire during the cranking thereof, the force of the impulse will be received by the stem 26 and the stop-support carrying the same, instead of being permitted to cause reverse movement of the crank 17. If it is desired to start the engine by making only partial turns of the starting-crank, instead of spinning or continuous turning thereof, the ma- 7 reverse movement of the crank. It may be noted that the parts are preferably so proportioned that the strength of the stop-pawl 26 is greater than that of the pins 16 and 19, sothat should the force of an impulse due to backfiring be great enough to cause breakage of any of the parts, one of said pins 16 or 19 will be sheared ofi instead of any other parts being broken. Such breakage would, of course, only occur under extremely adverse conditions, and the damage would be the minimum possible, involving merely the replacement of the sheared pin to restore the mechanism to its original condition.

Now, having described my invention, what I claim and desire to secure by Letters Patent is:

In a mechanism of the class described, the combination with an engine-shaft, a starting-shaft alined therewith, a bearing for the latter shaft in which the same is rotatable and longitudinally slidable, a toothed head on the starting-shaft adjacent to the engineshaft, means on the latter with which said toothed head is engaged by movement of the starting-shaft longitudinally toward the same, and a hand-crank carried by the start- 7 V as to be in operative relation to said stop when the toothed head is engaged with the engine-shaft, means for pressing said stop yieldably toward. the shaft-axis, and means for preventing movement of the stop toward said shaft-axis beyond the notches of the Copies of this patent may be obtained for wheel, said stop and notched wheel being engageable to prevent rotation of the starting-shaft except in the direction of normal rotation of the engine-shaft.

L. G. SHARP.

five cents each, by addressing the Commissioner of Patents, Weshinn, D. 43.

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