US1901996A - Starting device for internal combustion engines - Google Patents

Description

STARTING DEVICE FOR INTERNAL COMBUSTION ENGINES Filed Jan. 24, 1929 Q '2 Sheets-Sheet 1 w y x i\\ i ii ii 11 5 1: 40

N7 I 20 K1 m 51% March 21, 1933. A, T L I 1,901,996

STARTING DEVICE FOR INTERNAL COMBUSTION ENGINES Filed Jan. 24, 1929 2 Sheets-Sheet 2 5 1 J a f 2 7 ai T ,3 22 F V 1 /W A Patented Mar. 21, 1933 UNITED STATES GEORGE A. TAYLOR, OF HYDE PARK, MASSACHUSETTS STARTING DEVICE FOR INTERNAL COMBUSTION ENGINES Application filed January 24, 1929. Serial No. 334,656.

This invention relates to starting devices for internal combustion engines and with regard to certain more specific features thereof to automatically engageable and disengage able transmission mechanism governed by the action of an electric motor and by the action of the engine.

Heretofore transmission devices have been used involving a threaded armature shaft extension, or a threaded sleeve on such an extension, for causing axial movement of the pinion into engagement with a ring gear on the fly wheel of an engine. Usually in such devices a spring has been included directly in the drive for the purpose of relieving the shock of backfiring, neutralizing the action of the irregular movement of the engine as the cylinders pass over compression points and minimizing the deleterious effects of endbut-ting of the pinion teeth with the teeth of the ring gear. To some extent this arrangementof a spring in the driving connection has served its purpose along the directions indicated but not in a highly satisfactory manner and always with the objection that the springs become distorted and broken, rendering the device inoperative. Another objection has been in the decided shock of impact in such prior devices when the pinion is automatically engaged w1th the fly wheel gear. 'These objections have been recognized for many years and many attempts have been made to devise engine starter transmissions which would avoid some or allof these ob ectionable features.

The present invention has for one of its objects to provide an extremely compact and durable starter drive transmission which shall be highly efficient in operation; one in which the shock of engaging impact is re-. duced to a minimum; one 1n which the torque is transmitted in the starting operation through any of the springs involved.

The invention has for another of its objects to provide a device of the character above described which shall be extremely,

simple insofar as the number and size of parts employed are concerned and which shall be constructed at very low cost. 7 V V The invention accordingly consists in the various features of construction, combina tions of elements and arrangements of parts exemplified by the description hereinafter set forth the scope of the application of which is indicated in the appended claims.

In the drawings, i

igure 1 is a general assembly plan view showing the starter drive attached in operative position to an internal combustion engine; j

Figure 2 is a longitudinal sectional view of be improved star er drive in normally disengaged position.

Figure 3 is a view similar to Figure 2 showmg the parts in the positions assumed when the transnnsslon 1s complete.

Figure 4 is a View similar to Figure 3 showing the action of the parts occuring under the periodicincreased speed on the engine fly wheel as the engine passes over compression points or this figure may be, taken to indicate the preliminary action of the parts in disengagement of the transmission.

Figure 5 is a view in longitudial section of a modified form of invention showing the application of a multiple disk clutch in place of the cone clutch shown in Figures 2, 3 and 4. V

Figure 6 is a view in longitudinal section of another modified form of the invention showing the application of a separate.

threaded sleeve tothe armature shaft exten- 1 sion of the electric motor instead of cutting the threads directly on this extension as in Figures 2 to 5 inclusive.

Figure 7 is an end view of the starter shown in Figures 2, 3 and 4:.

Figure 8 is a sectional View taken on the line 88 of Figure 2.

Figure 9is a sectional View taken on the line 99 of Figure 5,

Figure 10 is a view of the large spring employed in the starter shown in Figure 6 which may be taken as generally typical of the large springs employed in the mechanisms shown in Figures 2 to 5 inclusive.

tension and has a bearing thereon as indicated at 25. This sleeve has a forward bore 26 and a rearward bore 27. A light coiled spring 28 surrounds the armature shaft extension 21 and has its forward end bearing against the stop washer 22 and its rearward end bearing against a shoulder 29 at the end of the bore 26. Arranged within the bore 27 of the sleeve 24 is a heavy compression spring 30 surrounding the threaded portion of the armature shaft extension and arranged between a shoulder 31, at the inner end of the bore, and an exterior cone clutch member 32 splined as at 33 on the sleeve 2%. By reason of the spline, the exterior cone clutch member 32 is adapted for relative axial movement with the sleeve 24, but is locked rotatively therewith. This clutch member has a conical friction clutch surface 34 adapted to engage with a friction clutch surface 35 of an internal cone clutch member 36 interiorly threaded as at 37 and engaged with the threads 23 cut on the armature shaft exten- "sion. A stop collar 40 is secured to the end of the armature shaft extension and has a forwardly extending-stop pin 41 against which the inner clutch member 36 is adapted to strike in its outward movement, thereby preventing the end of sand clutch member from jamming against the forward face of the stop collar. A pinion 42 is formed on the forward end of the sleeve. 7

In the normal disengaged position of the parts, the compression spring 30 is under no appreciable tension. The light spring 28 pressing against the sleeve 24 and reacting against the stop wash r 22 is under slight tension normally and urges the sleeve rearwardly creating a definite frictional engagement of the two parts of the cone clutch, so

that upon energization of the motor, the armature shaft rotates within the sleeve and its associated clutch, and the threads 23 cause a forward or axial movement of the assembled parts. No appreciable compression of the spring 30 takes place until axial movement of the assembly is resisted as by end-' butting of the teeth of the pinion with the of the pinion and fly wheel gear, the compression of the spring 30" is slight but sufficient to increase the degree of frictional enga ement between the 'clutch members, therel y causing the sleeve to rotate with the dri mg shaft. Slight rotation will be enough to carry the teeth into proper'meshing position, whereupon the spring 30 im mediately expands to its normal position and the axial movement of the sleeve is carried on until the end of the sleeve abuts the stop washer 22. Figure lmight be taken as illustrative of this last condition and it will be apparent that the spring 30 is .again compressed increasing the degree of friction between the clutch members from minimum to maximum. The axial movement of the clutch members is continued until the forward en d of the inner clutch'member 36 abuts a shoulder 36 on the driving shaft at which time rotative movement is transmitted from the driving shaft through the clutch to overcome the resistance of the engine under all ordinary conditions. To this end I use a relatively heavy spring as shown in Figure 10 of the drawings of approximately T g diameter spring steel wire.

As the engine varies in rotative speed going over compression points, a condition known as bobbing takes place in many starters of present day designs and sometimes results in complete demeshing and remeshing of the pinion with the ring gear. The present invention avoids any possible demeshing by reason of the fact that the clutch device assumes the reaction to the engine speed variations. No visible axial movement of the pinion or sleeve takes place in the present construction, but the engine variations are reflected in a visible axial reciprocation of the clutch. It will be obvious that when the fly wheel rotates faster than the speed im,

clutch member 32 is caused to follow closely. by the expansion of the spring 3O. As the engine again slows up as by approaching anotner compression point, the clutch member 36 1s agaln advanced carrying with it the outer clutch member 32 and recompressing the spring 30. All this takes place without any visible movement of the sleeve away from the stop washer 22;

If during the starting operation the engine backfires, the inner and outer clutch members slip and to this end the spring 30 is designed to allow such slippage. However, inasmuch as the spring 30 is not directly or positively connected to any of the parts and is not in a true sense in the drivingchain, there is no possibility of distortion of, or in jury to, the spring by reason of such backfiring.

7 When the engine commences to operate under its own power, the rotation of the ring gear 51 is much faster than the rotation of the pinion 42 under the influence of the electric motor with the result that the inner clutch member is moved axially rearward under the influence of the threads 23. This is efiected by reason of the continued frictional engagement of the clutch parts due to the is substituted for the cone clutch shown in Figures 2, 3 and 4. The alternate plates or disks in the outer clutch member are indicated at 60 splined to thesleeve as shown in Figure 9 of the drawings and the inner plates or disks 61 are shown as splined to a nut or inner clutch member 62 which has a threaded engagement with the armature shaft extension in the same manner as the inner clutch member 36 of the preferred form of the invention. 1

In the modification shown in Figure 6 of the drawings, instead of cutting'the threads directly on the armature shaft extension, an intermediate sleeve 65 having threads 66 formed thereon is arranged over an armature shaft extension 67. The sleeve is secured both rotatively and axially to the shaft by a screw 68, which also secures the end collar 69 to the end ofthe armature shaft. In this modification, the sleeve 24 is extended forwardly as at 70 to engage with a light spring 71 surrounding the inner end of the armature shaft. The stop washer in this modified form is shown at 72 hearing against a conical shoulder 7 3 on the shaft and cooperating with the bearing 74 of the sleeve instead of with the end of the sleeveas in the previous forms. The main purpose of the structure of this modified form is to adapt the invention to a standard type of armature shaft, the principles of structure and operation being substantially the same as in the other forms.

. It will be noted that the transmission of power in each instance is from the electric motor to the engine through a friction clutch while the actual engagement of the starter drive with the engine is by means of a gear butting of the teethoccurs. By reason of this construction, the shockof engaging impact is very greatly reduced. Full meshing of the pinion and ring gear must take place before the spring 30 can be sufficiently compressed to apply thenecessary friction on the clutch parts to overcome the resistances- 01f the engine. This compression is, of course,

gradual and progressive and the force of ro tative impact is app'liedso gradually as to reduce the shock to what is believed to be an absolute minimum in any electric motor starter which automatically engages with an engine gear upon the energization of the motor. 5

in prior starting devices damage to the teeth of en ine ring gears and starter pinions results, more frequently perhaps, upon'disengagement, than fromjamming or butting in the engaging operation. This is due to the control by the motor during the disengaging operation and at the instant of separation oneset of teeth brushes the other with a defi nite force and definite opposition. It is to be particularly noted in the present case that the heavy spring becomes relaxed before the actual disengagement of the pinion teeth with those of the ring gear, leaving only the light springeffective on the friction clutch, which permits relative slippage of the clutch parts at the instant of disengagement. This neutralizes the motor torque or reducesits opposition so as to prevent any damageto the teeth of either part in the disengaging operation It has been foundfin the practice of the present invention that it is unnecessary to specially shape or point the teeth of the'pinion although such special shaping or pointing may be adopted if desired.

What I claim 1s:- 1. A starting device for'an internal comfact that the pinion is under definite torque bustion engine, comprising in combination, H

means adapted to move axially into and out of engagement with an engine part, an electric motor having means. adapted upon energization'of the motor to move the first-said when the motor is originally energized, a 1

heavy coil spring adapted to prevent slip durmg engagement and application of the normal load but designed to permit slip upon backfire of the engine, said heavy resilient means becoming ineffective on the slip connection after the engine starts and before the V tively heavy compression spring arranged normally substantially lax between the member and a portion of the clutch, said heavy spring eing adapted to compress at the end of the meshing operation to substantially increase the degree of frictional engagement of the cone clutch parts.

3. A starting device for an internal combustion engine, having in combination, a driving shaft, aninner friction clutch member on said driving shaft means for moving said member axially upon rotation of said drivin the sleeve between a shoulder thereof and 7 ing shaft, a sleeve surrounding said sliaft,an

outer friction clutch member axially movable in said sleeve but locked therewith rotatively, a pinion carried on said sleeve. a spring withthe outer friction clutch member, another spring between the sleeve and a shoulder on said driving shaft.

4:. A starting device for an internal combustion engine,-having in combination, electric motor means with threaded shaft rotated therefrom, a friction clutch member threaded on said shaft. a sleeve surrounding said shaft, a second friction clutch member in said sleeve, a spring between the shaft and the sleeve hearing at one end against the sleeve and the other end against the second said clutch member, a pinion on said sleeve, and yieldable means normally holding the clutch membersin' light frictional engagement.

5. A starting device for an internal combustion engine, having in combination, a motor with threaded armature shaft extension, a sleeve loosely mounted on said shaft extension. a friction clutchpart threaded on said shaft extension, another friction clutch part splined' in said sleeve, a heavy compression spring arranged normally substantially lax between a shoulder on the sleeve and the friction clutch part splined therein. and a relatively light compression spring bearing against the forward part of the sleeve and reacting against a shoulder on the shaft, and means movable with said sleeve to engage and rotate an engine part, said light spring being under partial compression when the sleeve is at the limit of its movement away from the engine part.

member on the shaft, a coiled spring-within;

the sleeve, means for advancing the pinion and the clutch members along the shaft to mesh the pinion with an engine gear, and respective stops for the pinion and one of the clutch members whereby the pinion is first;

stopped and the clutch member is later stopped after the spring has been compressed a predetermined amount.

7. A starting device for an internal coinbastion engine, comprising a driving shaft i and ashaft to be driven, a pinion on they driving shaft, a friction clutch on the driving shaft, means for advancing the pinion and the clutch until the pinion connects with the shaft to be driven, a resilient means betweeni'. the friction clutch and the pinion and means for causing a limited relativeinovenient between a clutch part and the pinion after connecting the pinion with the driven shaft whereby the resilient meansis compressed and impresses a definite friction on the'clutch sufficient to turn the driven shaft under normal conditions but insufficient to hold under engine backfire conditions.

,8. A starting device for bustion engine, comprising in combination, an electric motor with extended armature shaft, a pinion adapted to engage an engine gear, friction clutch parts between the shaft and the pinion comprising. a control member threadedly mounted on said shaft and adapted to move axially thereon when the motor is energized, a clutch unit intermediate said pinion and said control member including a normally lax compressible spring, stop means integral with said armature shaft adapted to contact directly with said control member whereby the compression of said, spring is limited by the axial movement of said control member on the shaft.

9. An engine starting device comprising an armature shaft, a pinion thereon adapted to be moved into and out of mesh with an engine gear, a friction clutch between said shaft and said pinion, a spring surrounding said shaft, means operative by said shaft after meshing of the pinion with the engine gear for compressing the spring whereby the clutch friction is increased, and stop means acting directlyupon said compressing means to limit the maximum friction obtainable in the clutch.

10. A starting device for an internal combustion engine, comprising a driving shaft, a pinion mounted for rotary and longitudinal movement relative thereto, a friction clutch interposed between said pinion and said shaft, a coiled spring surrounding-said shaft, a control member for advancing the pinion along said shaft to mesh said pinion an internal com-- with an engine gear, said control member, after meshing of said pinion with said gear, compressing said spring to develop a progressively increasing torque in said friction clutch, and respective stops for the pinion and the control member whereby the pinion is first stopped and the control member is later stopped after the spring has reached a predetermined degree of compression.

11. A starting device for an internal combustion engine, comprising a driving shaft, a pinion mounted for rotary andlongitudinal movement relative thereto, a control member operatively connected to said shaft, a friction clutch interposed between said pinion and said control member a coiled spring surrounding said shaft, said control member, upon rotation of said shaft, advancing the pinion along said shaft to mesh said pinion with an engine gear and compressing said spring to develop a progressively increasing torque in said clutch, and respective stops for the pinion and the control member whereby the pinion is first stopped and the control member is later stopped after the spring has reached a determined degree of compression.

12. An engine starter drive comprising a power member, a transmission member mounted for rotary and longitudinal movement relative to said power member and connected to be driven thereby, an engine driving member connected to be moved by said transmission member into driving engagement with a member of the engine to be started, a yielding torque transmitting drive between the transmission member and the engine driving member, means for progressively building up torque in the transmitting device, and means for limiting such building up to a predetermined value.

GEORGE A. TAY OR.

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