US2204573A - Electrically operated engine starter - Google Patents

Description

June 1940- c. E. CLOUSTON 2,204,573

ELECTRICALLY OPERATED ENGINE STARTER Filed June 2, 1938 2 Sheets-Sheet 1 I/VVENTOA HIS JTTOR/VE) June 18, 1940. Q CLOUSTQN 2,204,573

ELECTRICALLY OPERATED ENGINE STARTER Filed June 2, 1938 2 Sheets-Sheet 2 mm E E Q a q mm W q a mm \A a on 4/ A 1 mm 8 a Q M Q Okcg rkai on/ haunt d 1..., 1940 V 2,204,573

UNITED STATES PATENT OFFICE Charles Edward (Houston, Osterley, England, as-

signor to Sperry Gyroscope Company, Inc New York, N. Y., a corporation of New York Application inne 2, 1938, Serial No. 211.425

In Great Britain June a, 1931 6 Claims. .(Cl. 290-48) The present invention relates to electrically there is mounted a clutch device 10 which operated engine starters for internal combustion lut h s shaft 6! to th sle v As sh wn, engines and the like wherein an engine-en a ing one plate II of this clutch is fixed on the shaft member of an electric starteris normally dlsenand anoth p ate 12 is s da along said gaged from a cooperating member on the engine h ft d i urged towards plate 7| b a Spring 5 starter-shaft, but is brought into engagement II which abuts at its farther end against a collar therewith at the time of starting. 14 which is pinned to shaft 62. Between plates According to the present invention an elec- "II nd 12 h re is interposed the base of a D- c lly perated engine starter comprises a sinshaped member I5 which serves as an intermedigle electric motor which is effective bothto bring ate clutch plate, and is screwed to a disc 69 10 the starter and engine into operative engagement secured to sleeve 41. Plates II, II, are shown and to crank the engine after engagement, and as faced with friction fabric, but clutch 10 may means enabling the starter clutch member to equally well be of the type using steel and phosfollow-up the engine clutch member should the p o -b Plates running in Due to the 15 engine overrun the motor duringcranking. action of spring I3, a constant pressure is ap- 15 Two embodiments of the invention will now pl d betw n u h plates I nd Causing be described by way of example with reference them to grip plate 15, and also to be centralized to the accompanying drawings, in which: on it; sleeve 41 and shaft 62 move together ax- Fig. 1 is a vertical longitudinalsectional view ially, but are capable of relative rotation when of one form of the engine-starter according'to the clutch III slips. 20 the invention; and Spring 35 abuts against a collar 33 pinned to Fig. 2 is a vertical longitudinal sectional view shaft 62. The whole assembly of j clutch of a modified form of the engine starter accordratchet clutch disc or body portion 25, shaft Y ing to the invention. 42, sleeve 4] and armature 45 is normally held Referring now to Fig. 1 of the drawings, the back by spring 32 so that the jaw clutch I is 25 electric motor 45 is arranged so as normally to out'of engagement with the engine jaw clutch I. have its armature rearwardiy offset from its field When current is supplied to the starter motor winding so that energisation of the motor. re- 45, its armature is at once pulled axially forsults in forward axial movement of its armature, wards into a central position relative to its field which movement is employed for eflecting enmagnets, and jaw clutch I engages with the 30 gagement of jaw clutches I. I'. Motor 45 has engine jaw clutch I'. its armature 46 provided with a hollow armature When the engine jaw clutch I' is engaged, the shaft 41 journalled at its rear end in a bearing resistance which it offers to turning, prevents 53' and splined at its forward end upon a sleeve motor 45 from driving jaw clutch I through 48 which, in turn, is splined to a tubular shaft sleeve 41, clutch-"I0 and shaft 62, since clutch in 35 49 that is journalled in anti-friction bearings 54 is arranged to slip at quite moderate loads. and SI. The starter, however, drives engine jaw clutch Tubular shaft 49 transmits the torqueof the I, through the reduction gearing which turns motor armature 46 to reduction-gearing of the 'sleeve 22', clutch disc 25 and ratchet toothing type disclosed in the prior patent to Hollis Walter 25, this drive being at a low speed. Should the No. 2,152,005, dated March 28, 1939, the final engine start up, the load on jaw clutch I will drive of which is ou ht out n Sleeve w c at once be removed, clutch disc 25 will be overis splined p y Portion 25 0 t e Sta te run, and clutch III cease to slip, so that there law clutch. This portion 25 is con ecte y will'be a direct high-speed driving connection atchet toot 26 t0 the ead P t 01 from armature 46 through shaft 41, clutch Ill, 45 the clutch, the head I and body 25 of the clutch shaft '2 t jaw clutch I, The jaw clutch I is being held together y sp then driven at high speed to keep in engagement The h llow r ure h f 41 on which the with the engine, slip simultaneously occurring at armature 46 of motor 45 is mounted, is continued the ratchet toothing 28. through the bearing 53', and has secured thereto It may be remarked that during the initial 50 a disc or collar 69. axial movement which brings jaw clutch I into The starter jaw clutch I is secured to the lam engagement with the engine jaw clutch I, there gitudinal shaft 62 which extends right through may also be rotation of the shaft 62 and jaw the motor and projects beyond the end of the clutch I. However the shock of engagement of 5 sleeve 41. On the projecting end of shaft 4! rotating jaw clutch I with engine jaw clutch I' 55 is very slight, since the inertia of jaw clutch I and shaft 02 is small. The slipping clutch II entirely insulates clutch I from the inertia eIIect of starter armature 46. Actually, very little rotation does actually take place in the circumstances mentioned, since the axial movement is so rapid.

Figure 2 shows a modified form of the invention in which spring 32 of Fig. 1 is omitted, the starter jaw clutch I being held out of engagement with jaw clutch I by a detent II pivoted on the electric motor housing at 11 and urged by a spring 18 against the inclined surface I! of the clutch housing ll, so that clutch II, and hence the armature l6 and the starter jaw clutch I, are held out of engagement until and unless motor "is supplied with current, when the magnetic pull between armature 48 and the field of motor overcomes the action oi detent "l8, and the starter jaw clutch I is carried forward into engagement with the engine jaw clutch I; detent It then exerts no force to disengage the two clutches I, I. This is advantageous since spring 32, shown in Figure i, might tend to throw jaw clutch I out oi engagement with law clutch I if the endwise magnetic pull between the motor field and its armature weakened due. to a decreasein armature current with increase in armature speed.

Figure 2 also shows a modified form of all clutch 10, in which metal plates II and II, splined on shaft 82, are gripped between'metal plates 82, 82' and t2" pressed by a spring I. Plates 82, 82 and 82" are splined in the clutch housing in which plate ll, against which spring 83 abuts, is screwed. Plate u is locked in position by a screw arranged to lock the screw threads of 84 together and thus prevent relative movement between members I. and II. A collar 85 and ball thrust 81 secure the shaft 02 to the clutch housing III and ensure that said shaft shall move axially with armature I, which is secured to clutch housing ll by a dog-clutch 8! and a screwed sleeve It, the sleeve 8! being prevented from rotating by the pin II.

The body portion 25 of the starter jaw clutch i is shown as journalled in an anti-friction bearing 9i while spring I is provided with a thrust block 92in the jaw clutch body 2!. Grease seals 98, 93 and 93" are fitted to retain lubricant in the gearing.

What I claimis:

1. An electrically operated engine starter comprising a single electric motor adapted to drive (i) a starter clutch member through a Iriction clutch capable of slipping at a predetermined load, and (ii) a driving member for said starter clutch member operated through reduction gearing, said member being formed with ratchet teeth to enable theformer to rim faster than the latter and ratchet thereover but to enable the latter to drive the former pomtively in one direction, the motor having an armature which is rapidly moved axially upon energisation o! the motor and serves to bring the starter clutch member portion into engagement with a clutch member on the engine shaft.

2.8tarteracoordingtoclaimlwhereinaxial movement 0! the armature is at all times opposed by a spring which tends to maintain the clutch member thereon out of engagement with the engine clutch member.

3. Starter according to claim 1 wherein axial movement of the armature to efiect engagement of the starterclutch member with the engine clutch member is opposed by a spring-urged detent which permits such movement when the motor is energised and resumes its opposition to movement only when the armature has been subiected to an opposite axial movement by thrust exerted between the starter and engine clutch members.

4. In an electrically operated engine starter of the jaw clutch type, a starting motor having a field, armature and shaft, a law clutch axially movable with said shaft, reduction gearing between said shaft and clutch for normal cranking, and a'direct connection from said shaft to said clutch including an overrunning device for maintaining the clutch teeth in rotational engagement during the cranking, said armature being biased to an out of line position with its field, whereby upon excitation of said motor an initial endwise thrust of said jaw clutch to efi'ect engagement I -between said hollow shaft and said first mentioned law to supply the requisite cranking torque to the engine.

6. In an electrically operated engine starter of the law clutch type, a starting motor having a field, armature and shaft, a jaw clutch axially movable with said shaft, reduction gearing between said shaft and clutch for normal cranking. a direct connection from said shaft to said clutch including an overrunning device for maintaining the clutch teeth in rotational engagement during the cranking, and a spring urged detent for normally maintaining said armature out of line position with its field, whereby, upon starting the motor, an initial endwise thrust of the Jaw clutch to eiIect engagement with the engine is efi'ected, said detent resuming Tits opposition to such movement only when the armature has been returned to its normal position by other means.

CHARLES EDWARD CLOUSTON.

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