US2696121A - Engine starting apparatus - Google Patents

Description

ENGINE STARTING APPARATUS I5 Sheets-Sheet 1 Filed Dec. l5, 1951 Dec. 7, 1954 Filed Dec. 15, 1951 P. L. SCHNEIDER ETAL yENGINE: STARTING APPARATUS 2SI Sheets-Sheet 2 Dec. 7, 1954 P. l.. SCHNEIDER ETAL 2,696,121

ENGINE STARTING APPARATUS Filed Dec. l5, 1951 s sheetsfshest 3 United States Patent O ENGHNE STARTING APPARATUS Paul L. Schneider and William H. Taylor, Anderson, Ind., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application December 15, 1951, Serial No. 261,894 13 Ciatms. (Cl. 747) This invention relates to engine starter devices of the type in which rotation of the starting motor shaft elects the meshing of a motor driven pinion with the engine fly-wheel gear and in which the pinion is automatically demeshed from the ily-wheel gear when the engine becomes self-operative, but in which means are provided to prevent disengagement of the pinion in case of a false start. Such means eliminates the necessity, in case there is a false start, of opening the starter switch and waiting for the starting motor to come to rest before closing the switch to repeat the starting operation; A starting device of this type is disclosed in the reissue patent to Schneider et al. Re. 23,359 and the present invention constitutes an improvement on the device disclosed therein.

In the device disclosed in the above mentioned patent, the driving pinion is held in engagement with the ilywheel gear of the engine by means of a detent which is released by action of centrifugal force, the effect of which is responsive to speed of rotation.

lt is the primary object of the present invention to provide means for holding the pinion in engagement with the fly-wheel gear which is positive in its action, so that the pinion is positively latched in its operative position and its release is in no sense responsive to speed, which is also so constructed that the release of the pinion can be effected without appreciable delay when the engine becomes self-operative and at lower motor speed than that necessary to effect release of the detent in the device disclosed in said reissue patent.

This object is accomplished by the provision of a latching device which is actuated by the movement of a member which is moved, when the starting motor circuit is closed and the pinion engaged with the ily-wheel gear, to a position to latch the pinion in gear engaging position and when the starting rnotor circuit is opened is moved to a position to release said pinion.

Further objects and advantages rof the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

Fig. l is a longitudinal sectional view, partly in elevation, of a starting motor equipped with a drive constructed in accordance with the present invention.

Fig. 2 is a view similar to Fig. 1,-but showing the latch means in latching position.

Fig. 3 is a fragmentary section showing a modiiied form of the starter drive shown in Fig. l.

Fig. 4 is a section similar to Fig. 3, but showing the latch means in operative position.

Fig'. 5 is an enlarged detail section of the latching device shown in Fig. l.

Fig. 6 is a detail section on the line 6-6 of Fig. 5.

Fig. 7 is a section similar to Fig. 6, but showing the latch means in latching position.

Fig. 8 is an enlarged fragmentary section on the' line 88 of Fig. 3.

Fig. 9 is a fragmentary section similar to Fig'. 8, but showing the latch means in latching position.

Fig. l is an elevation of the starter drive and showing in section a thrust absorbing device which may be provided if desired.

Fig. ll is a rfragmentary detail plan view of the starting motor shaft seen from the direction of the arrows in Fig. 10. n Y

Asbest shown ini Figs. lr and 2, the motor tield frame ICC 20 has a plate 22 secured in any suitable Way at one end, the main starter control switch which will be described later being supported by said plate. Secured to the other end of the field frame is a housing 24 which encloses the starter pinion 26 with its operating and controlling mechanism which controls movement of the pinion into and out of engagement with an engine gear indicated at 28 and rotation of the pinion. The pinion is rotated by the motor shaft 30 which is a hollow sleeve rotatably supported in suitable bearings 32 and 34, on the housing 24, and plate 22 respectively. The pinion 26 is both slidaole and rotatable on the motor shaft and the operatingmechanism effective to engage the pinion with the flywheel gear and drive the pinion will now be described.

A sleeve 36 having a relatively steep external helical thread 38 has a projecting llange 40 surrounded by a ring 42. A screw 44 is screwed into the flange and the end thereof extends into a hole in shaft 30 to hold the sleeve xed relative to said shaft. An outer sleeve 46 having an internal helical thread 48 which engages the external thread 38 is mounted on sleeve 36 and rotary movement of one of these sleeves relative to the other iects movement of the pinion 26 axially of the sleeve The sleeves are normally held in substantially the posiltion shown in Fig. l by a spring 56 which surrounds the sleeve 36 between the sleeve 46 and flange 40. One end of this spring is iixedly connected to the sleeve 46 and the other end to the flange 40 in any suitable way, for example, as shown in the above mentioned Reissue Patent 23,359. The spring acts both as a tension and torsion spring which assists in returning sleeve 46 from the Fig. 2 to Fig. 1 position and holds the sleeve in such position when the starting motor is not in operation. A stop member 52, which projects from the sleeve 46 can engage the ring 42 when the sleeve 46 is moved to the inoperative position.

The pinion is integral with an extending sleeve 54 which surrounds sleeve 30 and extends to the right of the pinion as seen in Fig. l and a split ring 56 is snapped into a groove adjacent the right end of the sleeve for a purpose which is explained later. A sleeve 58 having an internal diameter somewhat greater than the outer diameter of sleeve 54 surrounds such sleeve and has an inwardly projecting flange 60 which engages' sleeve 54 to the left of the ring 56. Sleeve 58 engages the sleeve 46 at its rightl end and at its left end engages splines 62 which are integral with and project inwardly from a ring 64, such splines extending into the spaces between the teeth of the pinion 26. The ring 64 and the sleeve 58 are permanently secured together in; any suitable Way. The right end of the sleeve 58 fits around a longitudinally projecting flange 66 which extends from the left end of the sleeve 46. As apparent in Fig. l, the left end of sleeve 46 at 70 is of less diameter than the right end of such sleeve and the outer diameter of the sleeve 58 is the same as that of the surface 70.

The normal location of the pinion 26 relative to the sleeve 58 isl determined by a spring 72 which lies between the right ends of the pinion teeth and the flange 6l) which projects inwardly from sleeve 58 and is urged by the spring to a position against the split ring 56.

The sleeve 46 and the sleeve 58 are coupled for rotational movement by a torque transmitting spring dil, which surrounds the sleeve 58 and the surface 7i) between a shoulder 82 formed on sleeve 46 at the right end of the surface 7i) and the` right endv of ring 64. The spring is retained in position by a cylindrical cover S4 having an inwardly projecting flange engaging the left end of the ring 64, and being bent inwardly at the other end to engage a groove S6 in the outer surface of sleeve 46. When the pinion 26 is moved into engagement with the flywheel gear, as later described, the turns of spring Si) tightly grip the surface 76 and sleeve 58 to apply the driving torque .to the pinion.

left until fully engaged with the y-wheel, in which position the pinion engages a washer 88 supported on shaft 30 and serving as a stop to limit the movement of the pinion to the left. When movement of the pinion to the left stops, the transmission of torque to the pinion builds up until sufficient to crank the engine and the latter is then rotated by the starting motor until it starts and operates under its own power. Since torque is transmitted through the spring 80, there is some slight delay in the application of full torque which, to some extent cushions the shock of torque transmission to the pinion.

ln the event that the end faces of the pinion teeth abut the end faces of the engine gear teeth before meshing, movement of the pinion to the left is momentarily stopped, but the sleeves 46 and 58 continue movement to the left and compress the spring 72 thus preventing the rapid increase in pressure which would be applied by the pinion teeth to the engine gear teeth if this spring '72 was not provided. This results in rotation of the pinion relative to the gear through the torque which is transmitted by spring 80 when tooth abutment stops axial movement of the pinion. Slight rotation of the pinion brings it to meshing position and the spring 72, which is compressed, then snaps the pinion into partial engagement of the gear and it is moved completely into engagement by the action of threads 38 and 48, until axial movement is stopped after engagement with washer 88.

The starting motor then cranks the engine until the latter becomes self-operative and tends to drive the pinion faster than it can be driven by the starting motor. When this occurs, the pinion is automatically demeshed, due to the action of the threads 3S and 48, and the demeshing movement of the pinion is aided by the action of spring S which has been additionally stressed both with respect to tension and torsion by the movement of the pinion to its driving position.

The mechanism previously described is very similar to that described in the Reissure Patent 23,359, differing therefrom only in certain specific details.

As shown in the drawings, the starting motor is energized by the closing of a main starter switch positioned in a cylindrical housing 90 which is secured by screws 92 to the plate 22. The switch includes fixed contacts 94 and 96, integral with binding posts 98 and 100 respectively, which are adapted to be connected to a suitable source of current such as a storage battery. The switch also includes a movable contact 102 carried by a block of insulating material 104 movably supported on a rod or stern 166 extending to the left in Fig. l, from an armature 108 of an electromagnet having a winding 110 adapted to be energized by the closing of a suitable switch (not shown). The control circuit of the electromagnet forms no part of the present invention and is not shown in order to simplify the disclosure. Any suitable control circuit and control switch for the aforesaid magnet can be employed.

The rod 106 has secured to its left end in any suitable way, a washer 112 and a spring 114 surrounds the rod between the washer and the block of insulating material 104. When the magnet is not energized a spring 116 holds the switch open as shown in Fig. l, but when the magnet is energized, the armature is moved to the right compressing springs 114 and 116 and closing the switch as indicated in Fig. 2. The spring 114 is stronger than spring 116 and exerts a pressure holding the switch closed when the magnet is energized. When the magnet is de-energized, upon opening of the control switch, the parts just described are returned to the Fig. l position.

In case of a false start, meaning one in which the engine fires a few times and then ceases to fire and stops, it is desirable that the pinion shall not be demeshed from the iii/wheel gear, but shall remain in its gear driving position. This will avoid the necessity of eifecting the opening of the starter switch and waiting for the starting motor shaft to become stationary before again closing the starter circuit to repeat the starting operation. 1f the pinion is held in engagement with the liywheel gear and a false start occurs, the starting motor circuit can simply be held closed and the starting motor will continue to rotate the pinion which will again drive the engine after the false start until the engine starts again and continues to operate under its own power. As already stated, in the device of the reissue patent above referred to, the pinion was held in engagement with the flywheel gear after a false start by a detent releasable by centrifugal action. According to the present invention, the applicants have provided a positively acting latch, the release of which is controlled by the de-energization of the starting motor and which has certain features of advantage over the earlier construction.

This latching means comprises two members and 122 which are received in openings on opposite sides of the shaft 30. When the parts are in the Fig. l position, these members engage the inner surface of the sleeve 54, but when the pinion is moved into its driving position, as shown in Fig. 2, the latch members are moved in opposite directions transversely to the axis of the shaft 30 to a position where they engage the right end of the sleeve 54 and when in such position the sleeve 54 cannot be moved to the right and the pinion cannot be demeshed.

To effect movement of the latch members in this manner, such members are received in a slot 126 in a member 128 integral with and extending to the left from the cylindrical head 130 of a short rod 132, the head 130 fitting within the hollow shaft 30 and being slidable therein. A pin 134 is supported in the member 128 and engages slots 136 and 138 in the members 120 and 122 respectively. These slots are arranged at opposite angles with respect to the axis of the shaft 30 as shown in Fig. 5, so that if the pin 134 is moved to the right, the members 120 and 122 are moved outwardly in opposite directions to the latching position which is shown in Fig. 7, and remain in such position until the pin 134 is moved to the left. When this takes place, the latching members are moved inwardly in opposite directions so that when the pin 134 reaches its original position, the latching members are restored to the position shown in Figs. 5 and 6.

In order to reciprocate the pin 134, as described, the short rod 132 is fitted within a hollow rod 140, which extends through most of the length of shaft 30 and rod 132 has a groove 142 into which the wall of rod 140 is crimped as shown in Fig. 5, in order to secure the rod 132 to rod 140. It will be understood, however, that the element 132 could be secured to the rod 140 in any other suitable way.

At its opposite end, the hollow rod 140 is secured in the same way as above described, to a short rod 144, to a reduced extension at the end of which a cupshaped washer 146 is secured by riveting or in any suitable manner. and the rod 144 is slidably supported in an opening formed in the closed end 148 of a cupshaped member 150, fitted tightly within shaft 30 and having a flange 152 engaging the end of the shaft. Positioned within the member is a spring 154, which lies between the end of member 150 and the washer 146. This spring normally tends to move the rod 144, hollow rod 140, and connected parts, including the member 136 and pin 134, to the right, but is normally prevented from doing so except when the winding 110 is energized because the force exerted by spring 116 is greater than that exerted by spring 154 and the stem 106, which engages the end of rod 144, holds such rod and the parts connected thereto in the Fig. l position, when the starter switch is open. When the winding 110 is energized and the starter switch is closed, however, the stem 106 is moved to the Fig. 2 position and spring 154 moves rod 144 and connected parts, including the pin 134, to the Fig. 2 position, moving the latch members 120 and 122 outwardly, as previously described, to a position at the right of sleeve 54, which has been moved to the left as the pinion is moved to its operative position and these members hold the pinion in its operative position until the control circuit is opened, the winding is de-energized and the main starter switch is opened. When this takes place, the stem 106 is moved to the left by spring 116, moving the pin 134 to the left and withdrawing the latching members to the inactive Fig. l position, releasing the pinion so it can return to its inoperative position.

It will be understood that although the spring 154 tends to move rod 140 to the right and the latch members to operative position as soon as the stem 106 moves to the right, movement of the rod 140 and the latch members cannot take place until the pinion is in gear engaging position because the latch members engage the inner surface of the pinion 54 and cannot move to latching position until such sleeve is in the Fig. 2 position.

If the control circuit and the main starter switch are not opened immediately upon the engine becoming selfoperative, the engine will rotate faster than the starting gesamt motor and the clutch device will slip, `permitting the pinion to rotate faster than the shaft 30 and the `sleeve 38 which is secured thereto. t

In the form of the invention shown in Figs. 3 and 4, the construction is exactly the same yas that shownin Figs. l and 2, except for a different construction of. the latch members 120 and 122', which correspond to latch members 120 and 122 and the operating .means therefor. In this form of the device, the latch members are positively moved to their inoperative position, but are moved to operative or latching position by centrifugal force, which is dependent upon the speed of rotation of the starting motor shaft during cranking of the engine. To effect operation of the latching members in this manner, the member 120 has a slot 160 and member 122 a slot 162 which are parallel to the axis of the shaft 30 and are best shown in Figs. 8 and 9. At the right end, these slots 160 and 162 are tapered as indicated at 164 in Figs. 3 and 4 and extending into the slots is a blade 166 of less width than that of the slots. This blade projects from an operating head 1767 secured to a rod 132 of exactlyr the same construction as rod V132 of the device show-n iu Figs. l and 2 and operated in exactly the same way. This operating head has a tapered surface 168 adapted to engage the surface 164 to effect movement of latch members 120 and 122 to the inoperative or unlatching position. As rod 140, which supports the operating head 167 is moved to the left when the starter'switch is opened, as has been previously set forth, the camming action between the surface 16S andthe surfaces 164 effects movement of the latch members 120 and 122' in a direction opposite to their direction of movement by centrifugal force so that at the completion of movement of rod 140 to the left, the latch members are restored to their original position and out of engagement with the end of the sleeve on which the pinion is supported. As soon as the latch members are thus rendered ineffective, the rotation of the pinion by the engine gear .at higher speed than the rotation of the starting motor shaft will effect withdrawal of the pinion from the engine gear automatically.

As already indicated, centrifugal force moves the latch members to operative position, that is, from the Fig. 8 to the Fig. 9 position. Obviously, in Fig. 8 the position of members 120 and 122' relative to the blade 166 is such that centrifugal force moves member 120 downwardly and member 122 upwardly to the latching position indicated in Fig. 9.

As already set forth, there is some slight delay in the application of full torque to the pinion through the spring clutch, which will, to a degree, Ycushion the shock of torque transmission when the pinion is engaged. -However, if desired, an additional means for `cushioning the shock may be added to .either of the starting Vdevices which have been described, such Lcushioning means being shown in Figs. l0 and ll. To effect this cushioning of torque transmission as described, the inner end of the screw 44 which is screwed into the sleeve 40 extends into a slot 170 in the motor shaft 30 of greater length than the end of the screw so that sleeve 40 has some slight axial movement relative to such shaft. A shoulder 172 is formed on shaft and positioned adjacent the shoulder is a washer 174 while a washer 176 surrounds shaft 30 adjacent the end of sleeve 40. Between these washers is a cushioning device comprising a pair of oppositely bowed Belleville washers 178 separated by a preloading spring 180 in the form of a disk having spring fingers formed thereon which can be bent to vary the degree of preloading. Upon sudden application of torque, the construction described can yield permitting a slight movement of the sleeve to the right cushioning the shock of torque application.

Although a magnetic starter switch is disclosed herein, it will 'be understood that the latch means and its operating mechanism could be used in a device having a manually operated starter switch if desired.

While the embodiments of the present invention as herein disclosed, constitute preferred forms, it is to be understood that other forms might be adopted.

What is claimed is as follows:

l. Starting apparatus for internal combustion engines comprising an electric starting motor having a rotating driving shaft, a driving pinion supported on and rotated by said motor shaft and adapted to rotate an engine gear to effect ,starting of the engine, means operative tation of the pinion to drive vsaid gear, a .switch forcennecting the motor with a current ksource when closed, latch members movable to positively lock said pinion `in engagement with the engine gear during operation yof the starting motor, resilient means for moving said latch members to operative position when axial movement of said pinion is completed, means operative to prevent operation of said resilient means when the motor switch is open and means operable upon closing of rsaid switch to render said last named means ineffective so as to permit operation of said resilient means.

2. Starting apparatus for internal combustion engines comprising an electric starting motor having a rotating driving shaft, a driving pinion supported on and rotated by said motor shaft and adapted to rotate an engine gear to effect starting of the engine, means operative upon energization of the starting motor for automatically moving the pinion axially on said shaft to effect engagement of the pinion with the engine and for effecting rotation of the pinion to drive said gear, a switch for con'- necting the motor with a y'current source when closed, latch members movable to positively lock said pinion in engagement with the engine gear during operation of the starting motor, a spring for moving said latch members to operative position when axial movement of the pinion is completed, spring means `operable to prevent operation of said iirst spring when said motor switch is open, and means operable upon closing of said motor switch to render said second spring ineffective in order to permit operation of said spring.

3. Starting apparatus for internal combustion engines.

comprising an electric starting motor having a rotating driving shaft, a sleeve rotatably and axially movable on said shaft and having a driving pinion secured thereto and adapted to rotate an engine gear to start the engine, means operable upon energization of the starting motor for eecting axial lmovement of vthe sleeve to engage said pinion with the engine gear and for causing said sleeve to rotate with the motor shaft, a switch for controlling operation of the motor and means for :operating said switch, latch members movable into engagement with the end of said sleeve when the axial movement thereof is completed to hold the pinion in gear engaging position, and lmeans operable in response to the .operation of said switch operating means to disengage the latch members from said `sleeve to permit return of the sleeve and pinion to normal position.

4. `Starting vapparatus for internal combustion engines comprising an electric starting motor Ihaving a rotating driving shaft, a sleeve rotatably and axially movable on said shaft and having a driving pinion secured thereto and adapted to rotate an engine gear to start the engine., means operable upon energization of the starting motor for leffecting axial movement of the sleeve to engage said pinion with the engine gear and for causing said sleeve to rotate with the motor shaft, a switch for controlling operation of the motor and means for operating said switch, a pair of latch members fixed with respect to movement axially of the motor shaft but movable transversely thereof, means operable after the sleeve is moved to bring the pinion into engagement with the engine gear to move said latch members transversely of the shaft to a position where they engage the end of said sleeve and hold the pinion in its gear engaging position, means operable to disengage said members from the end of the sleeve to permit disengagement of the pinion from the engine gear, said means for operating the latch members being controlled by operation of the means for opening and closing ofthe starter switch.

5. Starting apparatus for internal combustion engines comprising an electric starting motor, a driving pinion adapted to rotate an engine gear to effect starting of the engine, said motor having a single hollow shaft operable to rotate said shaft and supporting the motor armature and said pinion, means for moving the pinion axially on said shaft to eifect engagement of the pinion with said engine gear, latching means for holding the pinion in engagement with said gear during operation of the starting motor, a switch for controlling opera- 'tion of Ithe starting motor, a rod positioned within the hollow shaft and movable axially with respect thereto to effect operation of said latching means, and means operable by movement of the rod upon closing of the switch to positively move the latching means to operative position and operable by movement of the rod upon opening of the switch to positively retract the latch means to ineffective position.

6. Starting apparatus for internal combustion engines comprising an electric starting motor having a hollow operating shaft, a driving pinion supported on and rotated by said hollow shaft and adapted to rotate an engine gear to effect starting of the engine, means operable upon energization of the starting motor for moving the pinion axially on said shaft to effect engagement of the pinion with said engine gear, latching means for holding the pinion in engagement with said gear during operation of the starting motor, a switch for controlling operation of the starting motor, a rod positioned within the hollow shaft and movable axially with respect thereto to effect operation of said latching means, and means operable in response to closing of said switch for moving said rod to a position to effect movement of said latching means to position to engage one end of said pinion when the pinion is moved into engagement with the engine gear.

7. Starting apparatus for internal combustion engines comprising an electric starting motor having a hollow operating shaft, a driving pinion supported on and rotated by said hollow shaft and adapted to rotate an engine gear to effect starting of the engine, means for moving the pinion axially on said shaft to effect engagement of the pinion with said engine gear, latch means movable upon engagement of the pinion With the engine gear to a position to hold the pinion in engagement with said gear during operation of the starting motor, a switch for controlling operation of the starting motor, a rod positioned within the hollow shaft and movable axially with respect thereto to operate said latching means and means operable upon opening of said switch to move the rod to a position to effect positive retraction of the latch from an operative position to an inoperative position in order to permit disengagement of the pinion from the fly-wheel gear.

8. Starting apparatus for internal combustion engines comprising an electric starting motor having a hollow operating shaft, a driving pinion supported on and rotated by said hollow shaft and adapted to rotate an engine gear to effect starting of the engine, means for moving the pinion axially on said shaft to effect engagement of the pinion with said engine gear, latching means for holding the pinion in engagement with said gear during operation of the starting motor, a switch for controlling operation of the starting motor, a rod positioned within the hollow shaft and movable axially with respect thereto to effect operation of said latching means, means operable upon closing of said switch to move said rod to a position to effect movement of the latch means into engagement with one end of said pinion and means operable upon opening of said switch to move said rod to a position to positive disengagement of the latch means in order to permit disengagement of the pinion from the engine gear.

9. Starting apparatus for internal combustion engines comprising an electric starting motor having a hollow operating shaft, a driving pinion supported on and rotated by said hollow shaft and adapted to rotate an engine gear to effect starting of the engine, means for moving the pinion axially on said shaft to effect engagement of the pinion with said engine gear, latching means for holding the pinion in engagement with said gear during operation of the starting motor, said latching means comprising a plurality of members movable diametrically with reference to said pinion into position to engage one end thereof a switch for controlling operation of the starting motor, a rod positioned within the hollow shaft and movable axially with respect thereto to effect movement of the said members to operative and inoperative positions, an electromagnet for operating said switch and means operable upon both energization and deenergization of said magnet for moving said rod to effect operation of the latching means.

10. Starting apparatus for internal combustion kengines comprising an electric starting motor having a hollow operating shaft, a driving pinion supported on and rotated by said hollow shaft and adapted to rotate an engine gear to effect starting of the engine, means for automatically moving the pinion axially on said shaft to effect engagement of the pinion with the engine gear when the starting motor is energized and for automatically disengaging the pinion from the engine gear when the engine becomes self-operative, latch means for holding the pinion in engagement with the engine gear, said latch means comprising a plurality of members movable in a direction normal to the axis of said pinion, a switch for controlling operation of the starting motor, a rod positioned within the hollow shaft and movable axially i, with respect thereto upon opening and closing of said switch, said rod being effective to move said members into engagement with one end of said pinion upon closing of said switch, and effective to move said members out of engagement therewith upon opening of said switch.

ll, Starting apparatus for internal combustion engines comprising an electric starting motor having a rotating driving shaft, a driving pinion supported on and rotated by said motor shaft and adapted to rotate an engine gear to effect starting of the engine, means for moving said pinion axially on said shaft to effect engagement of the pinion with said engine gear, latch means for holding the pinion in engagement with said engine gear during operation of the starting motor, said latch means comprising members movable by centrifugal force into latching position when the pinion has been moved into engagement with the engine gear, a switch for controlling the operation of the starting motor, and means operable in response to the opening of said switch to positively move the latch members to unlatching position, in order to permit disengagement of the pinion from the engine gear when said switch is opened.

l2. Starting apparatus for internal combustion engines comprising an electric starting motor having a rotating driving shaft, a driving pinion supported on and rotated by said motor shaft and adapted to rotate an engine gear to effect starting of the engine, means for moving said pinion axially on said shaft to effect engagement of the pinion with said engine gear, latch means for holding the pinion in engagement with said engine gear during operation of the starting motor, said latch means comprising members movable by centrifugal force into latching position when the pinion has been moved into engagement with the engine gear, a switch for controlling the operation of the starting motor, means normally holding the latchl members in inoperative position and movable upon closing of said switch to a position to permit movement of said members to latching position, and means operable .in response to the opening of said switch to move said last named means to a position to effect withdrawal of the latch members from the latching position, in order to permit disengagement of the pinion from the engine gear when the control switch is opened.

13. Starting apparatus for internal combustion engines comprising an electric starting motor having a hollow operating shaft, a driving pinion supported on and rotated by said hollow shaft and adapted to rotate an engine gear to eiect starting of the engine, means for automatically moving the pinion axially on said shaft to effect engagement of the pinion with the engine gear when the starting motor is energized and for automatically disengaging the pinion from the engine gear when the engine becomes self-operative, latch means for holding the pinion in engagement with the engine gear, said latch means comprising a plurality of members movable in a direction normal to the axis of said pinion, a switch for controlling operation of the starting motor, a rod positioned within the hollow shaft and movable axially with respect thereto upon opening and closing of said switch, means operable upon closing of the switch to move said rod in a direction to effect movement of said members into engagement with one end of said pinion to prevent disengagement thereof from the engine gear, and means operable upon opening of the switch to move said rod in the reverse direction to effect disengagement of said members from said pinion, so as to permit disengagement of said pinion from the engine gear.

` (References Yon following page) References Cited in the le of this patent Number UNITED STATES PATENTS 450,231 Number Name Date 2,323,196 Buxton June 29, 1943 5 Nun be. 2,423,068 Hood et a1. June 24, 1947 437 28 2,446,458 Buxton Aug. 3, 1948 Name FOREIGN PATENTS Country Great Britain Date Dec. 12, 1938

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