US2142942A - Engine starter drive - Google Patents

Description

Jan. 3, 1939. C, s JANES L 2,142,942

ENGINE STARTER DRIVE Filed Deo. 9, 195e 2 sheets-sheet 1- HWENTORv Mmes/S: l BY/Cmm/ S; Janes ATTORNEY. y

Jam 3, 1939. C. s JANES ENGINE STARTER DRIVE 2 Sheets-Sheet 2 Filed Dec. 9, 1936 INVENTOR. Y

BYv/Ccn/on// c/an/es 7L ATTORNEY.

Patented Jan. 3, 1939 UNITED STATES PATENT OF FICE ENGINE STARTER DRIVE-y Application December 9, 1936, Serial No. 115,014

13; Claims.

The present invention relates to an engine starter drive of the type which automatically engages and rotates a member of the engine to be started upon energization of the source of power, and more particularly means for insuring such engagement under all conditions of operation.

In that type of starter drive employing a pinion moved longitudinally into mesh with, an engine gear by actuating means such as a screw shaft driven from the starting motor, it frequently happens that the teeth ofthe pinion do not come opposite the tooth spaces of the engine gear so that the teeth of the pinion and gear abut, and it is necesasry to index the pinion slightly to secure proper registry for meshing. The time interval necessary to allow this indexing of the pinion to take place is usually provided by permitting the pinion-actuating element to move back against a spring until the friction in the screw threads builds upsufficiently to index the pinion, whereupon the spring expands and snaps the pinion into mesh.

It is an object of the present invention to provide a novel starterdrive of the type described in which means are provided for indexing the pinion independently of friction in the actuating device, and Without the necessity of imparting longitudinal movement thereto.

It is another object to provide such a device in which the indexing of the pinion is brought about by the continued movement of the actuating mechanism therefor after the meshing movement of the pinion has been interrupted by the tooth abutment.

It is a further object to provide such a device in Which the indexing device is readily susceptible to variations in configuration to vary its action in accordance with special requirements.

It is another object to provide such a device in which the pinion is mounted directly on the armature shaft of the' starting motor so that the pinion may be of small diameter.

It is another object to provide such a device which is of unitary construction so that it can be conveniently merchandised and handled.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawings in which:

Fig. l is a side elevation partly in section of a Apreferred embodiment of the invention showing the parts in normal or idle position;

Fig. 2 is a similar view showing the parts in driving position;

Fig. 3 is a similar View showing the parts in thepositions assumed in casey of tooth abutment between the pinion and engine gear;

Fig. 4 is a cross-section taken substantially on Referring first to Fig. 1 of the drawings, there is illustrated a power shaft I which may be the extended armature shaft of the starting motor, not shown. A hollow sleeve 2 is xedly mounted on the shaft I by any suitable means such as indicated at 3, and a screw shaft is freely journalled on the sleeve 2 and is yieldably connected for rotation therewith by a yielding driving connection indicated generally by the numeral 5 and including a torsion spring 6 having flattened convolutions. A control member in the form of a nut 'I is threaded on the screw shaft, its longitudinal movement being limited by a thrust ring 8 which bears against. a stop nut 9 threaded on the sleeve 2.

A pinion II is freely journalled on the shaft I and is movable thereon into and out of engagement. with a member such as a flywheel. gear l2 of an engine toy be started. Means for actuating the pinion II from the control member l are provided including abarrel I3 splined on the nut 'I as indicated at I4, and a pair of cooperating camniembers I5 andY I6, the member I5 constituting a transmission member splined in the barrel yas indicated at Il, and the member it beingrigidly anchored tol-the pinion as shown at |81 and being in effect a part thereof. The cam member I6 is retained in the barrel by means of a thrust ringy I9 locked in the barrel. The control member I is similarly retained by means of a lock. ring 2l, and the longitudinal travelof the control member I- in the barrel islimited by a thrust ring 22.

Longitudinal motion of the control member. 'I in a direction to mesh the pinion II. is transmitted from the control member to. the cam member I5 by means ofV thrust bars 23. located inthe splines of the barrel and rigidly connected to the control. member I as by being Welded thereto. 'Ille length of these thrustV bars isso related to the height of the inclined cam sur- Means are provided for normally maintaining v the cam members in extended relation in the form of a spring 26 which may, as shown, be a torsion spring, and means are provided for normally maintaining the barrel in its idle position as shown in Fig. 1 in the form of an anti-drift spring 2'I located between the control member 'I and the thrust ring 8.

In order to prevent rebounding of the barrel with its assembled parts when the drive is demeshed, the threads of the shaft 4 are preferably terminated adjacent the idle position of the control nut 'I whereby the control nut is permitted to run olf the ends of the threads and rotate idly until its momentum is dissipated. Means for insuring reengagement of the threads on the control nut I and screw shaft 4 is provided in the form of a reentry spring 28 located between the thrust ring 8 and the cam member I5.

In the operation of the engine, starting with the parts in the positions illustrated in Fig. 1, rotation of the power shaft I is transmitted through sleeve 2, yielding driving connection 5 to the screw shaft 4, and since the control nut 1 is prevented from immediately rotating by reason of its inertia and the inertia of the barrel and connected parts, the nut threads itself along the screw shaft until it engages the thrust ring 8. This longitudinal motion of the control nut 'I is transmitted to the cam member I5 by means of the thrust bars 23 which are freely slidable in the bottoms of the spline grooves in the barrel, passing outside the thrust ring 22. This longitudinal movement is transmitted to the pinion II by virtue of the action of the spring 26 which maintains the cam members I5 and I6 in extended relation, and the barrel I3 is accordingly moved longitudinally by the pinion. When the thrust ring 22 in the barrel engages the thrust ring 8 on the sleeve 2, further longitudinal motion of the barrel is prevented and the meshing position of the pinion II is thus defined. Further longitudinal movement of the control nut I causes the cam member I5 to be forced into full engagement with the cam member I6 until the control nut 1 engages the thrust ring 8. Further rotation of the screw shaft 4 causes it to move back against a thrust washer 29 interposed between the parts of the yielding driving connection, whereupon the parts are clamped together for rotation in unison and cranking of the engine as illustrated in Fig. 2.

When the engine starts, the overrunning action of the pinion II due to the rapid acceleration of the engine gear I2 causes the barrel and its associated parts to overrun the screw shaft 4 whereby the control nut 'I is threaded back to its idle position, withdrawing the pinion II from mesh, and thereafter rotating idly on the unthreaded portion of the screw shaft until its momentum is dissipated.

If during the meshing movement of the pinion its teeth should abut against the teeth of the flywheel gear, longitudinal movement of the pinion is arrested, and the continued forward movement of the control member 'I causes the cam member I5 to move forward against the action of the spring 2S and index the pinion by reason of the cooperation of the inclined surfaces 24 and 25 on the cam members. As soon as the pinion has been rotated sufficiently by the action of the cam members to cause its teeth to register with the tooth spaces of the flywheel gear, the spring 25 expands and moves the pinion I I into initial mesh with the engine gear, whereupon the meshing action is completed and cranking takes place in the usual manner. It will be understood that the contour of the cam members I5 and I6, and in particular the slope of the cam surfaces 24 and 25 may be so designed as to cause the indexing of the pinion to take place as a result of a comparatively light pressure between the pinion and flywheel teeth. Moreover, since the longitudinal movement of the barrel and control member is not stopped by such abutment, it is clear that the impact of the teeth of the pinion against the teeth of the flywheel will be comparatively light.

Although but one embodiment of the invention .has been shown and described in detail, it will be understood that other embodiments are possible and various changes may be made in the design and arrangement of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In an engine starter drive, a power shaft, a pinion slidably mounted thereon for movement into and out of mesh With a member of an engine to be started, a nut, means including a screwthreaded connection for connecting the nut to said shaft, and means including a barrel member connecting the nut for longitudinal and rotary movement with the pinion, said last mentioned means including an inclined connection operative to index the pinion with respect to the barrel when the meshing movement of the pinion is interrupted.

2. In an engine starter drive, a power shaft, a pinion having a rotatable and slidable bearing thereon for movement into and out of mesh with a member of an engine to be started, a nut, means including a screw-threaded connection for connecting the nut to saidshaft, and means transmitting rotation and longitudinal movement from the nut to the pinion including a barrel member and a cam connection operative to index the pinion when its meshing movement is interrupted.

3. In an engine starter drive, a power shaft, a pinion slidably mounted thereon for movement into and out of mesh with a member of an engine to be started, a nut, means including a screwthreaded connection for connecting the nut to said shaft, means including a barrel member for transmitting rotation from the nut to the pinion,

and means including a pusher element for transmitting longitudinal movement from the nut to the pinion, said last means including a cam connection operative to index the pinion with respect to the barrel when the longitudinal meshing movement of the pinion is obstructed.

el. In an engine starter drive, a power shaft, an actuating member connected thereto for longitudinal movement thereof and rotary movement thereof and therewith, a pinion journalled on the shaft and slidable thereon to engage and drive a member of the engine to be started, a transmission member having a longitudinally yielding cam connection with said pinion, means transmitting longitudinal movement of the actuating member through the transmission member to the pinion, and means limiting the longitudinal movement of the pinion, said last means including means to connect the actuating member and transmission member for rotation in unison.

5. In an engine starter drive, a power shaft, a screw shaft mounted thereon and connected for rotation therewith, a nut threaded on the screw shaft, a pinion slidably mounted on the power shaft for movement into and out of engagement with a member of an engine to be started, a transmission member having a longitudinally yielding cam connection with the pinion, a barrel splined on the nut and transmission member, means transmitting longitudinal motion from the nut through the transmission member to the pinion, and means including said barrel for limiting longitudinal movement of the pinion.

6. In an engine starter drive, a power shaft, a screw shaft mounted thereon and yieldably connected for rotation therewith, a nut threaded on the screw shaft, a pinion slidably mounted on the power shaft for movement into and out of engagement with a member of an engine to be started, a transmission member having a cam connection with the pinion, a barrel splined on the nut and transmission member, means transmitting longitudinal motion from the nut through the transmission member to the pinion, and means in the barrel for limiting longitudinal movement of the pinion and of the nut.

7. In an engine starter drive, a power shaft, a screw shaft mounted thereon and connected for rotation therewith, a nut threaded on the screw shaft, a pinion slidably mounted on the power shaft for movement into and out of engagement with a member of an engine to be started, a transmission member having a Cam connection with the pinion, a barrel splined on the nut and transmission member, means transmitting longitudinal motion from the nut through the transmission member to the pinion, stop means for the nut, and means including abutments in the barrel cooperating with the stop means and pinion to limit the longitudinal movement of the barrel and pinion.

8. In an engine starter drive, a power shaft, a screw shaft mounted thereon and connected for rotation therewith, a nut threaded on the screw shaft, a pinion slidably mounted on the power shaft for movement into and out of engagement with a member of an engine to be started, a transmission member having a cam connection with the pinion, a barrel splined on the nut and transmission member, means transmitting longitudinal motion from the nut through the transmission member to the pinion, stop means for the nut within the barrel, and means including abutments in the barrel cooperating with the stop means and pinion to limit the longitudinal movement of the barrel and pinion, said means for transmitting longitudinal movement from the nut being arranged to clamp the transmission member against the pinion when the parts are in their limiting positions as dened by said stop member.

9. A self-contained engine starter drive unit including a sleeve adapted to be fixed on a power shaft, a screw shaft mounted thereon and connected to rotate therewith, a nut threaded on the screw shaft, stop means for said nut on the sleeve, a barrel splined on the nut, a cam member splined in the barrel, a thrust member in the barrel spacing the nut and cam member, a pinion mounted in the barrel having cam surfaces cooperating with said cam member, and abutments in the barrel retaining the nut and pinion therein and limiting the longitudinal movement of the barrel with respect to the stop means.

10. A self-contained engine starter drive unit including a sleeve adapted to be fixed on a power shaft, a screw shaft mounted thereon and yieldably connected to rotate therewith, a nut threaded on the screw shaft, stop means for said nut on the sleeve, a barrel splined on the nut extending beyond the sleeve, a cam member splined in the barrel, a thrust member in the barrel spacing the nut and cam member, a pinion mounted in the barrel so as to protrude therefrom having cam surfaces cooperating with said cam member, abutments in the barrel retaining the nut and pinion therein, and limiting the longitudinal movement of the barrel with respect to the stop means, and yielding means normally urging the cam member away from the pinion.

11. In an engine starter drive, a power shaft, a pinion freely mounted thereon for movement into and out of engagement with a member of an engine to be started, a barrel member, and means for translating and rotating the barrel and pinion in unison from said shaft including means for indexing the pinion relative to the barrel upon the continued longitudinal movement of the barrel when the longitudinal movement of the pinion is stopped.

12. In a unitary starter drive assembly, a hollow pinion having a smooth bore adapted to be journalled on a drive shaft, a mounting sleeve, a hollow screw shaft journalled thereon, yielding driving means connecting the sleeve and screw shaft, a nut threaded on the screw shaft, a transmission member having a cam connection with the pinion, means connecting the transmission member for rotation and longitudinal movement with the nut, and means including an abutment on the sleeve for limiting the longitudinal movement of the pinion.

13. In a unitary starter drive assembly, a hollow pinion having a smooth bore adapted to be journalled on a drive shaft, a, mounting Sleeve, a hollow screw shaft journalled thereon, yielding driving means connecting the sleeve and screw shaft, a nut threaded on the screw shaft, a transmission member having a cam connection with the pinion, means including a barrel member connecting the transmission member for rotation and longitudinal movement with the nut, an abutment on said sleeve, and stop means in the barrel engageable with the abutment and the pinion for limiting longitudinal movement of the pinion,

CLINTON S. JANES.

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