US2407158A

US2407158A - Engine starter drive

Info

Publication number: US2407158A
Application number: US586199A
Authority: US
Inventors: Burr W Jones
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1945-04-02
Filing date: 1945-04-02
Publication date: 1946-09-03
Anticipated expiration: 1963-09-03

Description

sept.3,194s. BWJQNES l 2,407,158

ENGINE STARTER DRIVE Filed April 2, 1945 dat@ kvm I N VEN TOR. Bywyv/U @Zones A TOBNEY Patented sept. 3, 194s UNITED STATES PATENT oEFlCE;

Burr W. Jones, Elmira, N. Y., assig'nor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application April 2, 1945, Serial N0. 586,199

I aclantis. (o1. vi-n l This invention relates to engine starters of the i class in which a starting motor is automatically coupled to an engine member for cranking the engine. 1

It is an object of the present invention to provide a novel starter for internal combustion engines which is dimensionally small without sacricing sturdiness and long life.

- It is a further object to provide a simple, compact starter of clean design,`the parts` of which can be manufactured by low-cost machining opyielding member therebetween, thus aiding in reducing the overall diameter to the minimum.

It is a further object of such a device to provide unitary means for assisting in the disengagement of the starter pinion and preventing the pinion from drifting against the engine member While in the inoperative position.

A further object is to provide such a device comprising traversing means having a thread of comparatively large diameter and low helix angle to facilitate the traversal oi the pinion member.

A further object of such a device is lto provide a starter pinion of small size and driving and supporting means for the pinion wherein bending moments are reduced to a minimum.

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

Fig. 1 is a side elevation of the device partly in vertical section, the parts being shown in inoperative position;

Fig. 2 is a view similar to Fig. 1 showing the parts in operative position; and

Fig. 3 is an expanded view in perspective of the pinion and the actuating means therefor.

In Fig. 1 of the drawing, there is illustrated a power shaft I, journalled in a bearing 2 in the frame 3 of a starting motor. A traversing and power transmitting member in the form of a sleeve 4, interiorly threaded as shown at 5, is

xedly mounted on the end of the power shaft by means of a bushing 6 xed in the end of thesleeve, and a pin I passing diametrically through the sleeve, bushing and shaft. The pin is retained by any suitable means such as a ring 8 surrounding the sleeve and crimped in place as indicated at 9. An anti-frictionv thrust bearing I0 is preferably interposed between the bushing Ii and the motor frame 3. A thimble II having a smooth cylindrical interior surface I2 is threaded Within the sleeve 4 for longitudinal movement therein toward and away from the bushing 6.

A cranking member in the form of a pinion I3 is mounted coaxially with the sleeve 4 for traversal into and out of engagement with an engine member suchas a flywheel gear I4. The end of the pinion is reduced in diameter so as to t slidably within the thimble II, and a yielding driving connection between the thimble and Dinion is provided in the form of a cylindrical block I5 of elastically deformable material such as rubber, fitting loosely within said thimble in abutting relation tothe pinion. It it is deemed desirable, the rubber block I5 may be bonded to the adjacent surface of the pinion IB. The mounting means for the pinion comprises an extension thereof in the form of a stub shaft I'I fixed integrally therein in any suitable manner, as by brazing or Welding, and slidably journalled in a bearing I8 provided in an outboard housing I9 rigidly mounted on the motor frame 3. A spring 20 is seated in a cylindrical recess 2l of the stub shaft I'I bearing at its other end on a fixed closure disc 22 to assist in demeshing the pinion and maintaining the pinion in demeshed position. .A disc 23 of non-metallic material, preferably fiber, is set into the bushing 6 of sleeve 4 for the purpose of preventing. noise when the pinion member and .its associated parts are thrown back to idle position,V The longitudinal movement of the pinion into engagement with the .engine gear is limited by an anti-friction thrust bearing 24 seated against the housing I9 and slidably receiving the stub shaft I1.

In the operation of this device, rotation of the power shaft I and the sleeve 4 by the starting motor causes thimble II, by virtue of its inertia, to be threaded to the left in Fig. 1, which motion is transmitted through the `rubber block I5 to the pinion I3, causing it to move into mesh with engine member until stopped by the thrust bearing 24. Further movement of the thimble causes the elastic block I5 to be placed under compression and thereby expands it radially into frietional Contact with the inner surface I2 of the thimble. When the rotation of the thimble is thus arrested, it is compelled to rotate with the sleeve 4, which rotation is transmitted through the rubber block I5 to the pinion member I 3. Inasmuch as the stub shaft I'I is solidly anixed to 3 the pinion and the pinion is forcibly pressed against the thrust bearing 24 when power is applied to crank the engine, it is obvious that the pinion will be very rigidly supported in its bearing i8. During the traversal of the pinion into full mesh with engine gear Ill, the combination antidrift and demeshing spring 20 is compressed and is held in the compressed position until the engine starts. When the engine res, the acceleration of the engine gear causes the pinion and: its associated parts tooverrun the sleeve 4, where;

by the thimble l I is threaded back to idle position with the assistance of the spring 20 which demeshes the pinion and holds it in demeshed position.

As shown in Fig. l, the sleeve 4 encloses the member substantially enclosing said block and movable parts oi' the drive sor as to preventU foreign matter such as dust, dirt and grease from` n fouling the Working parts. l1 for mounting the pinion I3 is solid with the pinion, no interior bearing is necessary which permits an absolute minimum root diameter of the pinion teeth. This feature improves the leverage of the starting motor on the engine.

It will be seen that there is here provided a sturdy and simple engine starter drive which is compact and easily assembled, small in size and sure in its operation. Although but one embodiment of the invention has been shown and described in detail, it will be understood that other embodiments are possible and the parts may be rearranged or altered in proportion without departing from the spirit of the invention as disclosed in the appended claims.

What is claimed is:

l. In an engine starter drive, a power shaft, a sleeve extension fixed thereon, a thimble threaded in the sleeve, a block of elastically deformable material in the thimble, a pinion normally housed within the sleeve and engaging said block, a bearing in which the pinion is slidably journalled for, movement by said thimble out of said sleeve into mesh with a gear of an engine to be started, and means for limiting the yprojection of the pinion from the sleeve.

2. An engine starter drive as set forth in claim 1 in which the compression of the block, due to the screw-jack action of the sleeve and thimble, expands the block into frictional engagement with the interior of the thimble, and. further including yielding means for returning the pinion to idleA position within the sleeve when the pinion overruns the power shaft.

3. In an engine starter, a power shaft, a pinion adapted to be driven thereby mounted for movement away from the shaft to engage and crank a member of an engine to be started, and means for actuating the pinion from the shaft including a pair of threaded sleeves. one of which is connected to rotate with the shaft and encloses said pinion when in idle position, and torquecushioning means for said pinion in the form of a yielding driving connection between the other of said threaded sleeves and thev pinion.

4. An engine starter drive for internal combustion engines including a cranking member adapted to engage and crank a member of an engine to be started, a motor shaft, means actuated thereby including a pair-of interthreaded members for causing engagement of Isaid crank- Since the stub shaftf having means cooperating with the housing member for traversing the pinion into engagement with the engine member.

6. In an engine starter, a bearing, a cranking *member having an extended bearing portion slidably journalled therein and adapted to engage and crank an engine member, a power shaft, means for actuating the cranking member from the power shaft including an elastically deformable member adjacent said cranking member, an exteriorly threaded thimble enclosing said elastic member, and a housing member xed to the power shaft vand having a threaded engagement of low helix angle with said thimble for traversal of said cranking member toward said bearing upon acceleration of the power shaft.

7. An engine starter drive comprising a pinion member journalled by an extended portion thereof in an outboard bearing t0 mesh and demesh with a member of the engine to be started, said pinion extension having a recess, a spring having one end seated in said recess and maintained under initial compression, tending to demesh the pinion, a motor shaft and a housing sleeve xedly mounted thereon, means including a thimble within the sleeve having an inclined connection therewith, and cushioning means in the thimble adapted to engage and transmit the longitudinal movement of the thimble to the pinion to mesh the .pinion upon acceleration of the motor shaft.

8. .An engine starter drive including an inboard andan outboard bearing, a power shaft journalled in said inboard bearing, a hollow sleeve open at one end and provided with threads of low helix angle on its interior surface, said sleeve being xed t0 said power shaft, a pinion member journalled in said outboard bearing having an axial recess, a closure of the outboard bearing, and a helical spring seated at one end in said recess and bearing at its other end against the closure, a block of elastic material attached to said pinion member, and a thimble in frictional engagement with said block, threaded within said hollow sleeve.

9. An engine starter drive characterized by an inboard and an outboard bearing, said bearings being. adapted to carry axial and radial thrust, a power shaft journalled in said inboard bearing, a pinion member slidably journalled in said outboard bearing and means actuated by the power shaft including concentric sleeves having an inclined connection therebetween and an elastic block forinitially thrusting said pinion against Said outboard bearing and subsequently compressing said elastic block to apply driving torque to the pinion.

BURR W. JONES.