US1285949A - Starting mechanism for gas-engines. - Google Patents

Description

A.W.CO

STARTING MECHANISM ENGINES APPLICATION FILED 915.

1,285,949. Patented Nov. 26, 1918,

INVENTOR A/mon IM Cop/9 4 BY mw w/ TTORNEY UNITED V STATES PATENT OFFICE.

ALMON W. COPLEY, OF WILKINSBURG. PENNSYLVANIA, ASSIGNOB. TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

STARTING MECHANISM FOR GAS-ENGINES.

Application filed April 6. 1915.

To all whom it may concern:

Be it known that I. Amrox IV. Corner. a citizen of the I'nited States. and a resident of 'ilkinsburg. in the county of Allegheny and State of Pennsylvania. have invented a new and useful Improvement in Starting Mechanism for Gas-Engines. of which the following is a specification.

My invention relates to starting mechanisms for gas engines and it has particular reference to such mechanisms as embody automatic means for controlling the operative connections of starting motors to the engines of automobiles or other motor vehicles.

One object of my invention is to provide a simple and convenient arrangement whereby a starting mechanism may be applied to theengine shaft of a motor vehicle.

A further object of my invention is to provide a means for preventing the oscillations of a spring which connects two relatively rotatable members. incident to periodic variations in the load connected to one of the members.

In the construction of starting mechanisms of the same general character as that of my invention. in which a resilientconnection is employed. the devices are of such length that their application to the engines of motor vehicles is diflicult because of the small available space adjacent to the engine of the fly wheel. It has been customary to provide a shaft having relatively rotatable parts which are connected by a helical spring that is connected at its respective ends to the rotatable parts of the shaft. The shaft is provided with a screw-threaded portion upon which a pinion is adapted to reciprocate into and out of mesh with the engine fly wheel. In addition to the parts above noted. it is necessary to provide portions of the shaft for journals. The length of the resulting structure is, therefore, considerable.

It is well'known that. in the operation of cranking an engine, the torque required to rotate the engine shaft depends upon whether the engine is approaching or receding from one 'of its several points of highest compression in the engine cylinders. When the engine shaft is rapidly rotated by a starting mechanism embodying a resilient connection the periodic variations of the load upon the motor tend to induce oscilla- Specification of Letters Patent.

Patented Nov. 26, 1918.

Serial No. 19,481.

tions of the spring constituting the .resilient connection between the relatively rotatable parts. The oscillations of the spring tend to automaticallvefi'ect the disconnection of the pinion from the fly wheel of the engine.

According to the present invention. I provide a gear wheel. which is mounted upon one of the relatively rotatable parts of the shaft. with a recess which may be occupied by one of the terminal loops of the spring. This arrangement permits a material decrease in length of the mechanism and thus facilitates its application to the engine fly wheel. I provide. also. a substantially cylindrical sleeve for inclosing the helical spring which forms a part of the driving connection and which limits the expansive movement of the spring. The contractile movement of the spring is limited by the parts which it connects. these parts being surrounded by the spring.

In the accompanying drawing. Figure 1 is a side view. partially in elevation and partially in section. of a starting mechanism constructed in accordance with my invention, Fig. 2 is an end view. in section, of the recessed gear wheel and associated parts.

An engine fly wheel 1.1118 plane of which is indicated by dot and dash lines in Fig. 1, may be provided with gear teeth (not shown) for engagement with the driving means. A starting motor 2. which is here represented as an electric motor. has an armature shaft 3 which is connected. by means of a pinion a semi-cylindrical recess 12 in the hub portion of the gear wheel 5, and engages a screw or stud 13. The other end of the spring is connected to the shaft 7 by a bolt L1. The spring 10 is surrounded by a hollow cylindrical sleeve 15. the internal diameter of which is substantially equal to the external diameter of the spring when the latter is in its normal position.

The shaft 8 is provided with a screwthreaded portion 16 which coacts with corresponding internal screw threads of a pinion 17, to actuate the latter longitudinally 011 the shaft into and out of mesh with the gear teeth of the fiy wheel 1. according as the motor constitutes the driving 01' the driven member. The shaft 7 is rotatably supported, at its outer end. by a housing 18 which incloses the entire mechanism.

Xormally. the several parts are in their. respective illustrated positions. with the pinion 17 out of engagement with the fly wheel 1. To start the engine .'power may be supplied to the motor by any suitable means (not shown). The shaft T will be driven by ,the reduction-gear mechanism. the shaft 6 and the spring 10 at a comparatively high rate of speed. Because of the inertia of the pinion 17. the shaft 7 will be rotated rela tively to it. and the pinion will be actuated to the left to effect its engagement with the fly wheel 1. 'hen the pinion 17 has reached the limit of its outward movement. as determined by the length of the screw-threaded portion 16. it will rotate with the shaft '7 to crank the engine.

As the engine approachesv one of its several compression points. more power will be required to rotate the engine shaft and the spring 10 will. accordingly. be contracted by the relative rotative movements of the shafts 6 and T to cause the spring to firmly engage or grip the parts of these shafts that are surroimded by.the spring. 'hen the engine passes over the compression point, the engine shaft tends to accelerate at a rate that cannot be followed by the motor because of the speed ratio at which these parts are connected. The engine tends, therefore, to drive the motor and thus cause the spring to expand. These variations in load occurring during each revolution of the engine shaft correspond. in mmiber. to the engine cylinders.

If no restraining means were employed, the periodic variations in load would cause an oscillation of the relatively rotatable parts and the sprin These oscillations would. at certain periods, cause the spring to be expanded to an excessive degree. In the present case, however, the sleeve 15 operates to limit the increase in diameter of the spring 9 incident to its expansion, and thus prevents excessive relative angular movements of the terminal portions of the springs and the shafts 6 and T to which they are respectively connected. The sleeve thus operates to damp out the oscillation setup by variations in load. Y

Then the engine starts under its own power. the fly wheel rotates ata higher rate of speed than that at which it was driven by the motor, and the pinion is caused to overrun the screw-threaded portion 16 of the shaft 7. This relative movement causes the pinion 17 to be actuated to the right to its illustrated position, and the motor is thus disconnected from the engine. The circuit of the motor maybe broken by the operator at any time after the engine has started.

'hile I have shown and described a specific embodiment of my invention, it is understood that such modifications may be made as fall within the scope of the appended claims. without departing from the, spirit of my invention.

I claim as my invention:

1. In a starting mechanism, the combination with an engine member and a motor. of means for operatively connecting said motor to said member, said means comprising ascrew-threaded shaft, a pinioncoacting with said shaft, a spring and means for limiting the relative angular movements of the terminals of said spring in either direction.

2. In a starting mechanism, the combination with an engine member and a motor, of means for operatively connecting said motor to said member, said means comprising a screw-threaded shaft, a pinion coacting with said shaft, a helical spring and means for limiting the expansive and contractile movements of saidv spring.

3. In a starting mechanism, the combination with an engine member and a motor, of means for operatively connecting said motor ,to said member. said means comprising apair of relatively rotatable members, one of which is provided with screw-threads, a pinion coacting with said screw-threaded member, a spring for connecting said rotatable members and means, including said members, for limiting the relative angular movements of the terminals of said spring in either direction.

i. In a starting mechanism, the combination with an engine member and a motor, of means for operatively coimect-ing sai'd motor to said member, said means comprising a screw-threaded shaft. a pinion coacting with said shaft, a second shaft and a helical spring for connecting said shafts, and a cylindrical sleeve surrounding said spring.

5. In a starting mechanism,-the combination with an engine member and a motor, of means for operatively connecting said motor to said member, said means comprising a pair of relatively rotatable members, a gear wheel on one of said members having a recess. a spring for connecting said members, and means in said recess for engaging said sprin 6. In astarting mechanism. the combination with an engine member and a motor. of means for operatively connecting said motor to said member. said means comprising a pair of relatively rotatable members, a member mounted on one of Said rotatable members having a recess, a spring for connecting 7. In a starting mechanism, the combination with an engine member and a motor.

' of means for operatively connecting said motor to said member, said means compris- --mg a pair of relatlvely rotatable members, a gear wheel on one of said members having a recess, a spring for connecting said members, and a stud in said recess for engaging said spring. 1

8. In a starting mechanism for engines, the combination with a motor, of means for operatively connecting said motor to an engine, said meanscomprising two coaxial relatively rotatable shafts. one of said shafts being exteriorly threaded, a pinion having a threaded portion coacting with said threaded shaft, a spring operatively connecting said shafts and coaxial therewith whereby contraction of the spring is limited, and means whereby expansion of the spring is limited.

9. In astarting mechanism for engines, the combination with a motor, of means for operatively connecting said motor to an engine, said means comprising two coaxial relatively rotatable shafts, one of said shaft-s being exteriorly threaded, a pinion having a threaded portion coacting with said threaded shaft, a spring operat-itely connecting said.

shafts and surrounding portions thereof whereby contraction of the spring 'is limited, and means surrounding the spring whereby expansion thereof is limited.

In testimony whereof I have hereunto subscribed my name this 30th day of March,

ALBION w. COPLEY.

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