US2128939A - Starting apparatus for internal combustion engines - Google Patents

Description

R. HAMMER sept. s, l192.8.

2,128,939 STARTING APPARATUS FOR INTERNAL COMBUSTION ENGINES v Filed oct. 2s. 1954 A2 sheets-meet 1` Sept. 6, 1938.y R. HAMMER 2,128,939

STARTING APPARATUS FOR INTERNAL COMBUSTION ENGINES y Filed oct; 2:5, v1934 l 2 sheets-sheet 2 Patented Sept. 6, 1938 UNITED STATES STARTING APPARATUS FOR INTERNAL COMBUSTIGN ENGINES Richard Hammer, Winnenden, Germany, assigner to Robert Bosch Gesellschaft mit beschrankter lHaftung, Stuttgart, Germany Application october 23, 1934, serial No. 149,627 In Germany November 4, 1933 18 Claims.

The present invention relates to starting apparatus for internal combustion engines, in which the pinion is connected to the driving shaft by means of a friction clutch acting automatically through an axially movable pressure member and can be displaced longitudinally together with the driving shaft or relatively to it without substantial rotation relative thereto for engagement.v

The known starters of this kind have the dis- D advantage that the toothed rim of the fiywheel and the pinion are damaged or at least greatly worn if the teeth of the pinion, on engagement, impact with the teeth of the iiywheel, because when the teeth encounter each other the whole 5 torque of the starter is transmitted to the pinion. In order to overcome this drawback, it has already been proposed in electric starters to pro vide an auxiliary field, which during the engagement of the pinion can only deliver a small torque, in addition to which, after the engagement of the pinion, the main field which exerts `the full torque is put into circuit in dependence on the movement of the pinion. It has also been proposed to reverse the direction of rotation of the armature on the engagement of the pinion bythe auxiliary field. These apparatus have the Vdisadvantage that troublesome appliances are necessary to change over the field windings in dependence upon the position of the pinion.

.0 In order to overcome all these disadvantages,

according to the invention the pinion is connected to the starter shaft by a clutch for small torque for the engagement, and by a clutch for the full torque for starting up the motor.

:5 Four examples of construction according to the invention are shown in thel accompanying drawings, in which:

Figure 1 is a diagrammatic illustration of a starter.

L0 Figure 2 is a second form of the 'invention in longitudinal "section Figure 3 a section on the line 3-3 of Fig. 2. Figure 4 a. longitudinal section of a third method of carrying out the invention.

L5 Figure 5 a section on the line 5 5 of Fig. 4.

In Figure 1, a is the armature of an electric motor, and b the armature shaft which is borne at c and d. On the armature shaft a sleeve e is arranged so as to be rotatable and axially i0 displaceable. The end of the sleeve facing the bearing d is formed as a pinion f while the other end is provided with claws or clutch teeth g. The bore of the sleeve is enlarged at this latter end to receive a friction spring h, which 55 at one end is fastened to the shaft of the armature and bears on the inside of the sleeve. i is a locking pinwhich is inserted in a radial hole of the sleeve and can engage in an annular groove It in the armature shaft. m is a spring which tends to draw the pin outwards.

Externally the pin bears on a fixed stop 1L connected, for instance, to the casing of the starter, and having two steps o and p, which are so arranged that in the position of rest of the starter the pin engages in the groove k of the armature'shaft and in the contracted position is drawn out of the groove. On the armature shaft a friction clutch plate q is keyed. This has claws r which can engage vwith the claws g of the sleeve. s is a compression spring, which is arranged between the clutch plate q and the sleeve e, and t is the return springof the armature.

The mode of action is as followsz When the starter is switched on for starting` the motor, the rotating armature is attracted by the poles of the starter and thereby also the sleeve -e displaced by the spring s and rotated by the slip spring h. If the pinion engages without impact, the pin i is-drawn out of the groove k as soon as it comes below the step p of the stop n.' On further displacement, the pinion sleeve abuts against the projection u of the bearing d. Since the armature can now move still further, the claws r on the clutch q comeinto engagement with the claws g of the sleeve. I'he armature shaft and the sleeve are now coupled together by the clutch q. l

When the engine overtakes the starter, the armature is drawn back in known manner by the spring t and the sleeve pushed back by the driving pin v.

If tooth impacts on tooth, only the Weak friction clutch formed by the spring h is operative. A coupling of the sleeve e with the clutch plate q is hindered by the locking pin z', which in this position of the sleeve still engages in the groove k of the armature shaft and thus locks the armature shaft relative to the sleeve. As soon as the pinion has run itself into the spaces between the teeth of the flywheel, the sleeve lis unlocked, whereupon the further starting operation proceeds in the above described manner. The clutch for the full torque is thus cut in quite automatically.

A second method of carrying out the invenarmature shaft of an electric motor 2. On the armature shaft a sleeve 3 is arranged so as to be rotatable. The end of the sleeve situated at the Y tion is shown in Figures 2 and 3. Here, I is the end of the armature shaft is formed as a pinion I. whilst at the other end ofthe sleeve a thread 5 is provided, on which a nut 6 can screw. 'I'his nut forms a part of afriction clutch 1, which is to couple the armature shaft I with the sleeve.

3. The counter-part to the nut Ii is a shell I, keyed on to the armature shaft. Between the nut andv this shell, friction discs 9 and I3 are arranged in the usual manner, which engage lnl grooves II and I2 inthenut and the shell. I3 is a pressure plate for the friction discs, which plate I3 can bear against an abutment I4, and I5 is a flange of the nutl 6 serving as pressure mem-- ber of the clutch. One of the discs connected with the shell, namely the disc Illa, has lugs I6 engaging in the grooves of the shell which are extended beyond the edge of the shell. On the casing I'I of the starter is provided an annular disc I8, which forms a stop for the lugs I6 of the disc IIIa and lies on the side of the lugs facing the pressure plate I3. In the ange I5 of the nut 6, small compression springs I9 are insertedwhich gently press those discswhich 4lie between the flange and the annular disc against the latter. In the position of rest of the starter the distance a of the pressure plate I3 from thev friction discs is greater than the distance 'of the pinion l from the toothed rim v2II of the flywheel of the internal combustion engine.

The mode of action of this apparatus is as follows:

To start the internal combustion engine, the electric motor 2 is switched on'. The armature of the motor is in known manner attracted into the field of the motor, and thereby the pinion on the armature shaft moved towards the toothed rim of the engine. By this displacement of the armature the whole clutch I is likewise moved. 'Ihe small springs I9 of the nut 6 press the friction discs steadily in the direction of the pressure i plate I3 or annular disc I8, so that thus thev discs do not follow the motion of the armature but the pressure plate I3 approaches nearer and nearer to the friction discs. When the pinion has f tance p;'fthe pinion is held fast.

travelled the distance it begins to engage with the toothed rim 20. Since the distance is smaller than the spacing a of the pressure plate from the friction discs, these cannot come into operation until Athe pinion has already to a certain extent engaged in the toothed rim of the iiywheel, i. e., the friction plates 3, I0 can only all come into action when the pinion teeth are already in mesh with the flywheel teeth. the pinion is fully engaged, the'presure plate I3 has moved forward the friction discs so far that the disc I0a no longer bears on the annular disc I3 and therefore all the discs can be compressedV between the nut flange I5 and the pressure plate If however, pinion tooth impacts on flywheel tooth, which may occur after travelling the dis- The nut 5 is driven by the discs lying between the flange I5 and the annular disc IB and screws itself towards the discs. As in this position the pressure plate I3 does not yet bear on the friction plates, only the discs situated between the nut iiange I5 and the annular disc I3 are pressed together. Since the torque transmitted by a friction disc clutch is substantially proportional to the friction surfaces of the discs, the torque transmitted by the few discsin the example illustrated two discs- When change from low torque to high torque takes piaci automatically.

In the third example of construction, shown in Figures 4 and 5, in which the same references are adopted for the same parts as in Figures 2 and 3, the friction disc 25, which is preferably shaped like a pot, and bears on the flange disc I5 of the nutA i, is pressed by .a spring 26 against the ange I5 of the pressure nut 6. 'I'he spring 26 bears against an abutment 21, which is provided on the coupling shell 8. 'I'he spring 26 is so chosen that its pressure is overcome by the attraction force of the armature, when the nut 6 bears against the bearing 28. In this case the pressure plate I3 is moved forward so far towards the friction discs, that it presses these against the flange of the nut 6, whereby all the said discs become operative, i. e., the full torque of the armature is transmitted.

If tooth impactsv on tooth, only the friction between the flange I5 and the friction disc 25 is effective for the transmission of the torque from the armature to the pinion.

The starting apparatus according to the invention renders it possible to go to the full torque of the starter motor, before the pinion is engaged, without having to fear that in the engagement the pinion and the toothed rim of the flywheel will be damaged.

I declare that what I claim is:

1. Starting apparatus for internal combustion engines comprising a driving shaft, a pinion, driving means connected with said driving shaft and rotating the same before and after said pinion is in mesh with a toothed member of the engine, friction clutch means, in constant engagement, adapted to transmit only a'low torque from said shaft to the pinion, friction clutch means adapted to transmit the full torque of the driving means to the pinion and means for always automatically bringing4 said second-mentioned clutch means vinto operation after the pinion is in mesh with the toothed member of the engine but preventing said second mentioned clutch means from coming into operation until the pinion is in mesh with said member.

2. Starting apparatus for internal combustion engines comprising a driving shaft, a pinion adapted to mesh with a toothed member of the engine to be started, driving means connected with said driving shaft and rotating the same before and after said pinion is in mesh with said toothed member, friction clutch means, in constant engagement between said driving shaft and said pinion and means permitting operation of aportion only of said clutch means to transmit a low torque only during meshing of the pinion with said toothed member and for bringing into operation the remainder of said clutch means only after meshing of the pinion.

3. Starting apparatus for internal combustion engines comprising a driving shaft, a pinion adapted to mesh with a toothed member of the engine to be started, driving means connected with said driving shaft and rotating the same before and after said pinion is in mesh with said toothed member, friction clutch means including friction discs, a portion of which are in constant engagement, between said driving shaft and said pinion and means permitting operation of a. portion only of said friction discs 1to transmit a low torque only during meshing of the .pinion with said toothed member and for bringing into operation the remainder of the friction discs only after meshing of the pinion.

4. Starting apparatus for internal combustion engines comprising a driving shaft, a pinion, driving means connected with. said driving shaft, friction clutch means includingtriction discs between said driving shaft and pinion adapted to transmit the whole torque of the driving means to the pinion, pressure members at opposite ends of said friction discs and a fixed stop intermediate of said pressure members and means cooperto the pinion, pressure members'at opposite endsv of said friction discs and a fixed stop intermediate of said pressure members and means cooperating therewith and with said pressure members adapted to bring into 'operation only those friction discs located between itself and one of said pressure members during engagement of the pinion. Y

6. Starting apparatus for internal combustion i engines comprising a driving shaft, a pinion,

driving means connected with said driving shaft,

friction clutch means between said driving shaft and pinion including 'friction discs, a Adriving clutch member and a driven clutch member, one of said discs connected with the driving clutch 'member having a projection extending externally 1 of the drivingclutch member and a-xed stop adapted.l for engagement with said friction disc having said projection and means cooperating I therewith to causev this disc alone to come into operation during engagement of the pinion.

'7. Starting apparatus for internal combustion engines comprising a driving shaft, a pinion, driving means connected with said driving shaft, friction clutch means including friction discs between said driving shaft and pinion adapted to transmit the whole torque of the driving means to the pinion, pressure members at opposite ends of said friction discs, a fixed stop intermediate of said pressure members adapted to bring into operation only those friction discs located between itself and one of said pressure members during engagement of the pinion and springs between said pressure member and said discs for maintaining said discs in engagement with the stopv during engagement of the pinion.

8. Starting apparatus for internal combustion .engines comprising a driving shaft, a pinion,

driving means connected with saig driving shaft, friction clutch means between saiordriving shaft and said pinion including friction members associated with the driving shaft and the pinion respectively and means including opposed pressure members associated with the driving shaft and pinion respectively and a spring. abutting at one end against one of said pressure members and abutting at the other end against one of the friction members associated with the driving y shaft to press the same towards the other pressure member.

9. Starting apparatus for internal combustion engines comprising a driving shaft, a pinion, driving means connected with said driving shaft,

friction clutch means between said driving shaft and said pinion including friction members associated with the driving shaft and the pinion respectively and means including opposed pres,- sure members associated with the driving shaft and pinion lrespectively and a spring abutting at one end against one of said pressure members and abutting at the other end against one of the and abutting at the other end against one of the friction members associated with the driving shaft to press the same directly against the other pressure member which is associated with the pinion.

11. Starting apparatus for internal combustion engines comprising a` driving shaft, a pinion, driving means connected with said driving shaft and rotating the same before and after said pinion is in mesh withatoothed member of the engine, friction clutch means between said driving shaft and said pinion including friction discs associated with the driving shaft and thel pinion respectively, resilient means for pressing` certain of said friction discs togetherv to transmit a low torque from the driving shaft to the pinion during engagement of the pinion and means including a pressure member for causing engagement of all of said discs to transmit a-high torque after such engagement of the pinion and operable to always prevent engagement of all of said discs until the pinion is in mesh with said toothed member.

12. Starting apparatus -for internal combustion engines comprising a vdriving shaft, means for driving said shaft, a pinion, a multiple-disc clutch between said driving shaft and pinion, and means including an automatically acting pressure member and an abutment cooperating therewith operable to permit engagement of only a portion of the clutch discs during engagement of the pinion and to permit engagement of all of the clutch discs after engagement of said pinion.

13. Starting apparatusfor internal combustion engines comprising a driving shaft; a pinion, driving means connected with said driving shaft, friction clutch means including a portion subv stantially in engagement between said driving -secured against rotation on said sleeve and adapt- .ed to engage a member of the engine to be started,

a control member mounted on .said sleeve for longitudinal movement thereof and rotary movement therewith, and friction clutch means be- -tween said shaft and said control member comprising a high-torque friction clutch and a lowtorque friction clutch, said control member controlling the operation of said high-torque clutch,

and means cooperating with said control member means for imparting longitudinal and rotaryf movement to said shaft, a. driving member rotatably mounted on said shaftand longitudinally movabletherewith adapted to engage a member .of the engine to be started, a control member mounted on said driving member for longitudinal movement thereof and rotary movement therewith, a high-torque friction clutch and a lowtorque friction clutch between said. shaft and saidcontrol member, said control member controlling the operation of said high-torque clutch, and

`means cooperating with said control member for preventingoperation of Saidhigh-torque clutch until after engagementof said driving member with said engine.

16. Starting apparatus for internal combustion engines comprising a rotatable shaft mounted for longitudinal and rotary movements, driving means for imparting longitudinal and rotaryA movement to said shaft, a sleeve rotatably mounted on said shaft and longitudinally movyable therewith, a pinion secured against rotation on said sleeve and adapted to mesh with a member of the engine to be started, a nut threaded upon said sleeve for longitudinal movement thereof and rotary movement therewith, a hightorque friction clutch and a low torque friction 7 clutch between said shaft and said nut, said nut controlling the operation of said high-torque clutch, and means cooperating with said nut for preventing operation of said high-torque clutch until said pinion is in mesh with said engine member.

17. Starting apparatus for internal combustion engines comprising a rotatable shaft mounted for longitudinal and rotary movements. driving v between said shaft and control member and tension controlled by the latter, a second friction clutch of less #folique-transmitting capacity than sai(I main clutch alsol interposed between said shaft and said control member, and means cooperating with said control member for preventing operation of said.main clutch until after engagement of said driving member with said engine.

18. Starting apparatus for internal combustion engines comprising a rotatable shaft mounted for longitudinal and rotary movements, driving means for imparting longitudinal and rotary movement to said shaft, a driving member rotatably mounted on said shaft and longitudinally movable therewith adapted to engage a member of the engine to be started, a control member `mounted on said driving member for longitudinal only of said clutch means into operation to transmit a low `torque during engagement of said driving member with said engine and for bringing into operation the remainder of said clutch means after engagement of said driving member with the engine. v

RICHARD HAMMER.

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