US1905836A - Engine starter - Google Patents

Description

April 25, 1933. J. w. Frrz GERALD ENGINE STARTER Original Filed lay 19. 1928 www Patented pr. 25,

UNITED STATES PATENT OFFICE JOHN W. FITZ GERALD, 0F MILVAUKEE, WISCONSIN, ASSIGNOR T0 BRIGGS & STRATTON CORPORATION, OF MILWAUKEE, WISCONSIN, A CORPORATION 0F DELAWARE ENGINE STARTER Original application filed May 19, 1928, Serial No. 279,174. Divided and this application filed July 15,

1931. Serial This invention relates to starters for automobile engines, marine engines, airplane engines and the like, and is a division of Letters PatentNo. 1,804,757.

It is an object of this invention to provide an improved starter of simplified construction to reduce production costs and, at the same time, provide a more eflicientand practical structure.

The starters now in common use arek substantially as illustrated in the British patent to Galloway, et al., No. 6,824 of 1884, wherein a pinion gear is adapted to be thrown into mesh with a ring gear preferably xed to the engine fly wheel when the starting motor is operated and adapted to be disengaged therefrom upon the speed of the engine iy wheel becoming greater than that of the starter motor. This structure is not complete and hence not practical in that should the teeth of the gears fail to be in register when they engage, breakage results and in Letters Patent No. 1,116,137 O, issued Vincent Bendix, November 10, 1914, a yieldable drive connection for the starter gear shaft permits the necessary give7 should the teeth of the gears fail to mesh.

The latter structure is open to mechanical objections, as the spring crystallizes from constant use and when broken the entire starter is Vinoperative and this invention has as another object the provision of a starter for engines wherein the starter shaft is in substantially one piece and has means for permitting the desired give in the event the gears fail to properly mesh instantly upon the starter gear engaging the engine gear.

A more speciiic object of this invention resides in the provision of an improved starter for engines wherein the drive unit is yieldable axially under stress in the event the teeth of the starter gear fail to align with the teeth of the engine gear instantly upon their engagement.

lVith the above and other objects in View which will appear as the description proceeds, my invention resides in the. novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the append- No. 550,863. f

ed claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

In the accompanying drawing, I have illustrated several complete examples of the physical embodiment of my invention constructed according to the best modes I have so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a view, partly in side elevation and partly in section, of an electric starting motor embodying one form of my invention; and

Figure 2 is a view similar to Figure 1 illustrating a slightly modified form of my invention.

Referring now more particularly to the accompanying drawing, in which like nulmerals designate like parts throughout the several views, 5 designates an electric motor of suitable design and construction including a rotor 6 having its shaft 7 journaled in bearings 8 at opposite ends of the motor housing 9. One end of shaft 7 projects beyond the housing and is provided with an enlargement 10 which is fast thereto' and may be integral therewith if desired and is provided with external helical threads 11 on` which a 'pinion 12 is threaded.

In that form of my invention illustrated in Figure 1, whichis the out-board type of starter, the shaft 7 is preferably provided with a bearing support 13 positioned at the side of the 'engine ring gear liopposite to the starter motor. The ring gear 14 is preferably carried by the fiy wheel 15 of the engine, not shown, and as the rotor 6 is rotated by the closing of the motor circuit, not shown, the helical threads 11 cause the pinion 12 to be advanced axially and engage the gear' 14 of the motor, its engagement with thegear 141 being limited by a shoulder or collar 16 and its movement inwardly being restricted by a shoulder or a stop 17.

In the event the teeth of the pinion and ring gear fail to mesh as they engage, it is necessary that either the rotation or axial movement of the starter gear bek momentarily arrested until the teeth register. It is in this particular, that the structure illustrated in the British patent to Galloway fails, and this invention provides means for permitting the starter pinion to yield axially by mounting the entire motor unit so as to yield axially. Obviously various diierent means for mounting the motor housing may be employed and the drawing illustrates but tivo preferable. arrangements.

ln Figure l, the motor housing O is provided with a base lcl Ywhich re. s on a mounting bracket l5) of approximae y right-angular construction, having a horizontal motor supporting Wall Q0 and an upright end Wall 2l. This bracket may be supported from the engine structure not shovvn in any suitable manner. The motor supporting Wall 20 thereof is provided with a plurality ot elongated openingor slots .22 through which attaching bolts Q25 carried by the motor base 18 pass to secure the motor to the mounting bracket.

The motor is thus slidable on Jdie bracket for the length el" the slots 2, but is yieldahly urged to one iimit oi movement by an expansive spring -leon'ined betr-:een the upright Wall and tue adjacent end ol the motor, the spring 24- being maintained in position by a lug 26 extended from the end wall 2l, and by havingl its opposite end received in a poclret QT iormed in the end wall 25 ot the motor.

lf the teeth oi the gears fail to register during] operation, the entire motor unit moves axially against the action oi the spring 24 until the. teeth oit the pinion i2 and the ring gear l align. when the spring Zi will move the unit to the right with reference to the drawing and the gear l2 will continue its advance toits fully meshed position.

Figure 2 illustrates this invention as applied to starters of the iii-board type. In this modification the housing oi the motor 5 is of uniform cylindrical shape throughout and is slidably mounted in an outer casing or sleeve Q8 in which it is held against rotary movement by elongated keys or guides 29 formed on the inner Wall ot' the casing 28 and slidably received in suitable guide Ways in the motor housing. An expansive spring 30 coniined between the end ivall 3l of the casing 2S and the adjacent end 32 of the motor yieldably urges the motor in one direction.

The operation of this form ot the invention is substantiallyT identical Yith that shown in Figure l except that the direction of axial movement of the motor and also of the drive pinion is reversed.

From the foregoing description taken in connection With the accompanying drawing, it will be readily apparent to one skilled in the art to which an invention of the character described appertains, that by mounting the entire motor unit for axial movement to yield in the event of misa-ligament of the driving pinion with the teeth of the ring gear, the desired yielding act-ion in starters of this type is obtained in the simplest possible manner and hence, the production cost is greatly reduced. It is also readily apparent that starters constructed in accordance with this invention are etlicient in operation and embody a practical design.

'hat I claim as my invention is:

l. An engine starter, comprising the, combination with a. member operatively connected With an engine, a motor, a rotatable member, a. driving member mounted to travel longitudinally on said rotatable member into engagement with said engine member and also to rotate therewith, means mounting the motor for axial movement, and means yieldably resisting axial movementof the motor in a direction opposed to the direction of movement of the driving member to engage the engine member.

2. The combination with an electric motor including a rotor shaft and a drive member on the shaft engageable with a member to be driven, of means mounting the motor to aceoinmoda te axial movement thereof, means yield-ably resisting axial movement of the motor in one. direction, and cooperating means carried by the rotor shaft and the drive member for moving' the motor against said yielding means to preclude destruction of the driving member or the member to be driven upon improper engagement of the driving member with the member to be driven.

3. The combination with an electric motor including a rotor shaft and a driving member on the shaft engageable with a. member to be driven, of a mounting member for the motor,

means attaching said motor to the mounting member so as to accommodate limited axial movement of the motor, yieldable means resisting axial movement of the motor in one direction and normally maintaining the same in its opposite limit of movement, and cooperating means carried by the driving member and the motor shaft and operable to engage the driving member with the member to be driven and to move the motor axially against the yielding means in the event of improper engagement of the driving mem- 3er with the member to be driven to preclude destruction of the driving member and the member to be driven.

4. In an engine starter, the combination with a member to be driven operatively connected with an engine, of a motor including a rotor, a drive member carried by the rotor and engageable with the member to be driven, said drive member normally being disen` gaged from the member to be driven, screw means carried by the drive member and the motor rotor 'for advancing the drive member towards the member to be driven upon operation oi the motor, means mounting the means for the motor enabling limited axial movement of the motor and its rotor as a unit and holding the motor against rotation, and means yieldably resisting axial movement of the motor in a direction opposite to the direction of movement of the driving pinion to engage the gear member.

6. In an engine starter, the combination with a gear member associated with an engine, of a starting motor including a rotor, a driving pinion, means carried by the rotor and the driving pinion and operable upon operation of the starting motor to move the driving pinion longitudinally along the rotor into engagement with the gear member and to drive the gear member through the pinion upon complete engagement therewith, a

Vmounting member for the starting motor,

means attaching the starting motor to said mounting member so as to enable limited axial movement of the motor as a whole, and an expansive spring confined between one end of the motor and a fixed abutment yieldably resisting axial movement of the motor in a direction opposed to the direction of the movement of the driving pinion to engage the engine gear member.

7. In an engine starter, the combination with a gear member operatively connected with an engine, of a starting motor having a rotor, a driving pinion carried by the rotor, means carried by thefdriving pinion and the rotor and operable to engage the pinion with the gear member upon operation of the starting motor and to drive the gear. member upon complete engagement therewith, a mounting bracket having elongated slots whose longitudinal axes are parallel with the axis of the motor, attaching screws passing through part of the motor and received in said slots whereby the motor is mounted for limited axial movement, and an expansive spring confined between one end of the motor and part ofr said mounting bracket to yieldably oppose axial movement of the motor in a direction opposite to the movement of the driving pinion towards the gear member and to yield upon improper engagement of the drive pinion with the gear member so as to preclude injury to either the drive pinion or the gear member.

8. In an engine starter of the character described, the combination with a gear member operatively connected with an engine, of a starting motor having a rotor, a driving pinion on the rotor, means carried by the driving pinion and the rotor and operable to engage the driving pinion with the gear member upon operation of the motor and to drive the gear member through the pinion upon complete engagement thereof, a stationary supporting housing receiving the starting motor :tor axial sliding movement, means carried by said mounting housing and the starting motor to prevent rotation of the starting motor in said housing, and an expensive spring coniined between the starting motor and one wall of said supporting housing to yieldably oppose axial movement of the starting motor in one directionfand to yield upon improper engagement of the pinion with the gear member so as to preclude injury to the gear member or the pinion.

In testimony whereof I have hereunto afiixed my signature.

JOHN W. FITZ GERALD.

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