US2317953A

US2317953A - Engine starter gearing

Info

Publication number: US2317953A
Application number: US385716A
Authority: US
Inventors: James E Buxton
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1941-03-28
Filing date: 1941-03-28
Publication date: 1943-04-27
Anticipated expiration: 1960-04-27

Description

April 27 1943. J, E. BU XTON 2,317,953

ENGINE STARTER GEARING Filed March 28, 1941 2 Sheets-Sheet 1 witness: INVENTOR' I fi/WWMZM BY Jun Les 6. 5m

M %NEY April 27, 1943.

J. E. BUXTON 2,317,953

ENGINE STARTER GEARING Fil ed March 28, 1941 Q l I/iii l IV mm li/ 41 26a 18a 33a l F I p 56 1a a NVENTOR.

Y Ja/nes /6. 16mm how 2 Sheet-Sheet 2 Patented Apr. 27, 1943 ENGINE STARTER GEARING James E. Bux ton, Elmira Heights, N. Y2, assignor to Bendix Aviation Corporation, South Bend,

Ind., a corporation of Delaware Application March 28, 1941,, Serial No. 385,716

13 Claims.

The present invention relates to engine starter gearing and more particularly to automatically engaging gearing which is adapted to maintain the driving connection between th starting motor and the engine until the engine has be-- come reliably self-operative.

It is an object of the. present invention to provide a novelengine starter gear of the stated type incorporating a yielding driving connection, the yielding element of which comprises a body of elasticaliy deformable material which is placed under tension when; the starter is actuated.

It is another object to provide such a device in which the yielding element and its associated parts actas an, over-running clutch which permits the engine tooverrun the starting. motor when the engine starts.

It is a. further object to provide such a device in which the yielding element is placed under both tension and torsion duringv the cranking operation.

It is another object to: provide such a device in which the yielding element is provided with a portion which may be placed under compression to act as a friction. clutch to provide a supplemental. driving connection.

It is another object to provide such a device in which that portion of the yielding element which is under tension is arranged to stretch when a tooth of the pin-ion abuts against a tooth of the engine gear, and to contractand snap the pinion into initial mesh when the pinion. is indexed into proper position.

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

Fig. l isa side elevation partly in section showing a preferred embodiment of the present invention;

Fig. 2 is an end View from the right in Fig. 1;

Fig. 3 is a view similar to Fig. 1 showing the parts in driving. position;

Fig. 4 is an end. view from the left in Fig. 3;

Fig. 5 is a view similar to Fig.- 1 showing the parts in the positions assumed case of tooth abutment of the pinion and engine gear;

Fig. 6 is aside elevation partly in section of a driveaccording to the present invention showing a variation in the form and. method of attachment of the yielding driving member, the parts being shown in the positions assumed when the engine gear overrunsthe drive; and

Fig. 7 is a side elevation partly in section of a drive according to the present invention in which the yielding element is formed totransmit the major part of th cranking torque through the compression connection.

In Fig. 1- of the drawings there is illustrated a starter drive'includin a power shaft I having. a

sleeve 2 fixed thereon in any suitable manner as by'means of. a cross .pin 3'. Sleeve 2 is provided with. oppositely arranged flats 4 (-Fig. 4), and a driving barrel 5 have. a corresponding opening is fixed thereon against a flange 6 by means of a lock ring 1 which also serves to retain the cross pint.

A pinion 8 is slidably journalled on the power shaft lfor movement intoand. out of engagement with a member such as a ring. gear 9 (Fig; 3) of an engine to. be'started. Meansfor actuating the pinion from the barrel 5 are provided comprising a screw shaft H slidably journalled on the sleeve 2 and having a nut t2 threaded thereon,.which nut is rigidly connectedv with the pinion 8 by means of abarrel member I'3 fixed to'the pinion at one end' as indicated at M and. having. slots I5 in its other end for the reception of radial lugs It. on

the nut I2, the nut being retained in the barrel by a split lock ring l1.

Barrel 5 is provided with a driving head in the form of a bell-shaped enlargement l8 slotted at. [9 for the reception of radial lugs 2| on an annular plate member 22, the plate member being retained in the driving head by a split lock ring 231 Screw shaft H is provided with a driven head in the form of a radial flange 24, and a yielding driving member in the form of a cylinder of elastically deformable material 25, isloosely mounted in the barrel 5- and provided with a-rad-ial flange 26 clamped in the driving head l8 by the plate member 22, and having at its other end an inwardly extending portion 21. providing. a friction surface 28 adapted to engage the flange 240i screw shaft H and form a friction coupling connection therewith. Pinsor projections29 may, if desired, be seated or formed in the driving head [-8 to engage recesses in the flange 26 of the yielding driving member in order to more positively connect the yielding. driving member to the driving head. The sleeve 2 is provided with a stop nut 31 fixed thereon providing an abutment for the nut l2 to define the operative position of the pinion, and an anti-drift spring 32. is arranged between the nut 12 and the stop nut Si in order to: yieldingly maintain the pinion in idle position. A spring 33- is located in. a recess 34 in the end: of the screwshaft H bearing against the stop nut 3| in order to maintain the flange 24 of the screw shaft in light frictional engagement with the inwardly extending portion. 2] of the yielding driving member 25.

Means for holding the pinion in engagement with the engine member until the pinion rotates above a predetermined speed, is provided in the form of a centrifugal latch 35 'slidably mounted in the barrel I 3 in position to engage: the 'stop nut 3i when the parts are in. cranking position as illustrated in Fig. 3. The latch 35 is yieldingly held in operative position by suitable means by virtue of such connection. 'when indexing has been accomplished, the yieldshaft by a starting motor, not illustrated,

causes the screw shaft H to be rotated by virtue of its frictional connection with the yielding driving member 25, whereby the nut 12 with its associated parts are traversed to move the pinion 8 into engagement with the engine gear 9, at which time the nut |2 engages the stop nut 3|. Further rotation of the power shaft I thereupon causes the screw shaft to thread itself back away from the stop nut 3|, thus stretching and torqueing the yielding. driving member25 until sufficient torque has been built up to rotate the engine member. It will be understood that during this operation the increase in pressure of the flange 24 of the screw shaft against the surface 28 of the yielding driving member'prevents slippage of the clutch formed by these parts. If the resistance to rotation of the engine is sufficient to stretch the yielding member 25 until the inwardly extending portion 21 thereof becomes pressed against the inner end of the driving barrel 5 a supplemental driving connection is thus formed as shown in Fig. 3 whereby additional torque is transmitted directly through the friction clutch formed between the end of the barrel 5 and the portion 21 of member 25 which is adequate to rotate the engine under all circumstances.

When the engine starts, acceleration of the engine gear 9 causes the pinion 8 to overrun the power shaft whereby the screw shaft II is threaded back until it engages the stop nut 3|, thus relieving the tension of the yielding member 25 and withdrawing the flange 24 slightly from the surface 28 of the yielding member whereby the pinion and its associated nut and :screw shaft are disconnected from the power shaft and allowed to overrun freely. This con dition continues if the engine remains self operative until the rotation of the pinion and barrel |3 attains a speed sufficient to withdraw the latch 35 from engagement with the stop nut 3|. Spring 32 in conjunction with the conveyer action of the screw shaft and nut are thereupon effective to return the pinion and its associated parts to idle position. If the engine should not immediately become self-operative upon the initial explosions thereof, the pinion is held in mesh with the engine gear and when the rotation of the power shaft catches up with the rotative speed of the engine gear, the frictional connection between the surface 28 of the yielding member 25, and flange 24 of screw shaft 7 is re-established.

Cranking is then resumed until the engine becomes reliably self-operative, whereupon the acceleration of the pinion actuates the latch 35 to permit return of the parts to idle position.

If during the meshing operation a tooth of the pinion should abut against a tooth of the engine gear as illustrated in Fig. 5, the yielding member 21 will be stretched'until sufficient torque has been built up to index the pinion into proper relation to the engine gear. This may take place before the compressive connection between the end of the barrel 5 and the portion 21 has been established, or the indexing may be accomplished In either case,

.member 25' is made thinner and extends inwardly further than in the form first illustrated in order that all cranking loads except unusual or peak loads will normally be transmitted through tension and torsion of the stretched portion of the yielding member.

It will be understood that the member 25 is sufficiently flexible to permit it to be assembled on the screw shaft by flexing the opening in the :free end thereof into an oval shape and then passing the flange 24 of the screw shaft diagonally through said opening.

The remaining parts of this embodiment of the invention are the same'as previously described and are similarly numbered, and the operation of this device is the same as above set forth except that the major part of the cranking load is transmitted by tension and torsion of the cylindrical portion of the yielding member2'5'.

In Fig. '7 of the drawings a further embodiment of the invention is illustrated in which the yielding member 25a comprises a comparatively slender cylindrical portion 38 which is easily stretched for mesh-enforcing purposes, and a heavier and thicker inwardly extending block 39 which is adapted to transmit the major part of the cranking torque by the compressive connection between the flange 24 of the screw shaft and the inner end of the barrel 5a.

Fig. 7 also shows a variation in the method of attaching the end of the yielding member 25a to the driving barrel 5a. As there shown, the driving head lBa is interiorly grooved as indicated at 4|, and the terminal flange 26a of the yielding member is formed to fit such groove and to be wedged tightly in the groove by the action of a split lock ring 23a on a plate member 22a. If desired, the interior shoulder 42 formed adjacent the groove 4| may be interrupted periodically by radial grooves as indicated in dotted lines in order to form driving lugs for transmitting torque from the barrel 5a to the yielding member. I

The operation of this embodiment of the invention is the same as that previously described except that the meshing operation is more gentle by reason of the greater elasticity of the portion 38 of the yielding member 25a, and the major part of the cranking torque is transmitted by the compressive coupling between the end of the barrel 5a and the flange 24 of the screw shaft when the screw jack action of the screw shaft and nut squeezes the portion 39 of the yieldingmember between said elements.

Although certain forms of the invention have been shown and described in detail, it will be understood that other forms 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, a power shaft, a sleeve fixed thereon, a driving head rigidly connected to the sleeve, a screw shaft having a driven head slidably journalled on the sleeve, a nut threaded on the screw shaft, a pinion slidably journalled on the power shaft and rigidly connected to the nut, a stop on the sleeve defining the operative position of the pinion, and a cylinder of elastically deformable material connected at its ends to the driving and driven heads respectively and. yieldingly resisting separation of said driving and driven heads.

2. An engine starter according to claim 1 in which the cylinder of elastically deformable material is fixed to one of the heads, and frictionally connected to the other head.

3. An engine starter according to claim 1 in which the cylinder of elastically deformable ma terial is fixed to the driving head at one end and has an inwardly extending shoulder at its other end frictionally engaging the driven head by virtue of the screw jack action of the screw shaft and nut.

4. In an engine starter drive, a power shaft, a barrel member fixed at one end thereon having a driving head at its other end, a cylinder of elastically deformable material in the barrel having one end connected to be rotated by the driving head, a screw shaft rotatably mounted on the power shaft, extending within the cylinder and having a driven head connected to be rotated by the other end of the cylinder, a nut threaded on the screw shaft, and a pinion slidably journalled on the power shaft and rigidly connected to the nut.

5. In an engine starter drive, a power shaft, 2. barrel fixed thereon, a pinion adapted to en gage and drive an engine member, means for traversing the pinion into driving engagement and for rotating the pinion including a cylindrical member of elastically deformable material, means forming a tractive connection from one end of the elastically deformable material to the barrel, means forming a tractive connection from the other end of the elastically deformable material to the pinion, and means including an auxiliary yielding frictional connection provided by a portion of said yielding member for transmitting torque from the barrel to the pinion.

6. In an engine starter drive, a power shaft, a pinion adapted to engage and drive an engine member, and means for traversing and rotating the pinion including a screw shaft and nut, a cylindrical member of elastically deformable material and means cooperating therewith to provide connection between the power shaft and screw shaft, and an auxiliary yielding clutch connection between the power shaft and screw shaft closed by the screw jack action of the screw shaft and nut.

7. In an engine starter drive, a power shaft, a pinion adapted to engage and drive an engine member, and means for traversing and rotating the pinion including a cylindrical member of elastically deformable material and means forming a tractive connection therefrom to the pinion placing the elastic cylinder under tension when the drive is actuated, said tractive connecting means including a self-tightening overrunning clutch.

8. In an engine starter drive, a power shaft, a pinion adapted to engage and drive an engine member, and means for traversing and rotating the pinion including a cylindrical member of elastically deformable material, means connecting one end of said member to rotate with the power shaft and means forming a tractive connection from the other end of said member to the pinion, said tractive connection including a self-tightening overrunning clutch, means normally holding the clutch in initial engagement, and speedresponsive means for holding the pinion in engagement with the engine member and holding the clutch open to allow the pinion to overrun freely when the engine starts.

9. In an engine starter drive, a power shaft, a pinion slidably journalled thereon for movement into and out of engagement with a member of an engine to be started, and means for traversing and rotating the pinion from the power shaft including an elastic sleeve, transmission means tractively connected to the ends thereof, and a friction clutch closed after a predetermined amount of stretching of said sleeve to transmit torque from the power shaft to rotate the pinion.

10. In an engine starter drive, a power shaft, a pinion slidablyjournalled thereon for movement into and out of engagement with a member of an engine to be started, and means for traversing and rotating the pinion from the power shaft including a cylindrical member of elastically deformable material comprising an elastic sleeve and transmission'means tractively connected to the ends thereof, said elastic member also comprising a compressive block forming a yielding clutch member for transmitting torque from the power shaft to rotate the pinion.

11. An engine starter drive including a power shaft, a driving head rigidly connected thereto, a pinion, means including a screw shaft and nut for traversing the pinion into engagement with a member of an engine to be started and for rotating the pinion, and a cylinder of elastically deformable material having at one end a tractive connection with the screw shaft and at the other end a tractive connection with the driving head, one of said tractive connections being in the form of a friction coupling which is tightened by the screw jack action of the screw shaft and nut in stretching the cylinder.

12. An engine starter drive including a power shaft, a driving head rigidly connected thereto, a pinion, means including a screw shaft and nut for traversing the pinion into engagement with a member of an engine to be started and for rotating the pinion, and a cylinder of elastically deformable material having at one end a tractive connection with the screw shaft and at the other end a tractive connection with the driving head, one of said tractive connections being in the form of a friction coupling which is tightened by the screw jack action of the screw shaft and nut in stretching the cylinder, and further including a speed controlled detent for holding the pinion in engagement with the engine member.

13. An engine starter drive including a power shaft, a driving head rigidly connected thereto, a pinion, means including a screw shaft and nut for traversing the pinion into engagement with a member of an engine to be started and for rotating the pinion, and a cylinder of elastically deformable material having at one end a tractive connection with the screw shaft and at the other end a tractive connection with the driving head, said cylinder being provided wih means forming an auxiliary yielding fricton clutch connection between the power shaft and screw shaft.

JAMES E. BUXTON.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5,217,953 November 16, 1965 Erwin B. Bahnsen It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below. V

Column 9, lines 74 and 7S, strike out "and a sleeve bearing mounted on the roller means,"; column 10, line 8, for "mmebers" read members Signed and sealed this 20th day of September 1966.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST W. SWIDER Attesting Officer