US2163829A - Engine starter - Google Patents

Description

June 27, 1939.- T N 2,163,829

ENGINE STARTER Original Filed May 4, 1928 INVEIVTO v I I, I

' ATTOR/VE Patented June 27 1239 I i L UNITED STATES: PATENT OFFICE Roland Chilton, Keyport, N. 1., assignor, by mesne assignments, to Bendix Aviation Corporation, South Bend, Ind., a corporation of- Delaware Application May 4, 1928, Serial No. 215,188 Renewed January 26, 1938 22 Claims., (01. 123-119) This invention relates to engine starters and It will be appreciated that the momentum efmore particularly to the inertia type of starter i .fect of the starter flywheel, referred to the crankwherein the momentum of a rotating mass is shaft of the engine, increases with the square of utilized to effect, or to assist in the starting of, the gear ratio, which ratio is relatively high in an internal combustion engine. Inertia starters inertia starters. Thus in a typical case a five 5 of the prior art include an automatic' means pound flywheel on the starter is equivalent to a whereby the starter mechanism is disengaged five thousandpound flywheel of one foot radius from the engine as soon as the latter begins to attached to the crankshaft. With such a flyfunction under its own power and such devices wheel, the idling of the engine will be very greatly o usually effect such disengagemeht', even though improved and by the provisions of this invention the engine stalls after the first firing strokes. the starter flywheel is utilized in this way. l

One object of this invention is to provide a Taking as n ill r t on e a e f a tw lv starter having means whereby such disengage- 'cylinder engine, an inertia starter will normally ment may be delayed until the engine has run be cap of Producing bo te tur of the i long enough to avoid danger of stalling. crankshaft or in other words, the engine would 16 Another object of the invention is to provide ave to m -fl sixty consecutive times before an inertia type of starter wherein the engine may it stalls when the starter flywheel is maintained be so engaged thatfthe starter flywheel may act in rivin n e ion w th he n in acc rdin as an auxiliary engine flywheel to carryfthe ento the Provisions of this invehtiohso gine over the mis-fires that are apt to occur at stalli g of an engine occurs (without mis- .20 slow speeds and to smooth out the running of firing) whenever the speed falls low enough for the engine when idling and to permit a reduction e kinetic e g o the moving P s to be in the safe idling speed. N insumcient tocarry the engine over a compres- A further object of the invention is to provide $1011 ean inertia type of starter, which may be ener- This minimum Speed in the case of.aircraft' 35 gized from the engine while the engine is still engines, w h av r lativ y sl ht flyw l runni g and so ;be in readiness for a re-start effects, is relatively high, a d the augmentat should the engine stall or should it be desired to of the fly hee -e ects of the en ine parts. hr shut the engine off for a short period. I the utilization of the starter flywheel as an engine This invention is intended to be particularly flywheel while idling, W be expressed by millto useful in connection with engines, such as used tiplicatioh of thousands- I on'aircraft, which are characterized by the omis- W en a en ine isidl ns there is an intersion of the usual flywheel and, which therefore, change of n rgy tw n t e engine nd ts fivdepend on the relatively slight flywheel effect of. wheel member which take turns in driving ea the engine parts and propeller. As a result the. other during each cycle. Conventional inertia 35 minimum safeidling speed of such engines is Starters are provided with slipping clutches to undesirably high and the slow speed running is limit the shock of engagement to the predeterapt to be erratic, and stalling of the engine is apt mined torque at Which e clutch 1 y in to occur without warning as the result of relai i e where the starter remains in tively few misflres. gagement with the idling engine, a reversal of 4 In manoeuvering hydro-airplanes on the water, orque of the magnitude to which the starter for example, as for tying up to a dock, it is, found c c e p ef b y set m s t e e de u d e that the minimum safe idling speed produc a pounding on the gears. For this reason in the undesirably high manoeuvering speed wherefore. efened Showing there 15 incormra'ted a Over it is the common practice for the pilot to switch inning clutch of relatively low torque capac' .ofi his engine when he judges that his distance whereby e overrun torque is only a frac-- Y is appropriate for a gentle contact. This often tion.v of the maximum torque developed whe results in a failure to'm'ake proper contact with the starter drives the engine. In this way, a

' the dock whereby planes are often damaged or moderate acceleration is appli to the Starter;

commence to drift. Accordingly, one of the main and the engine is permitted to Speed up and 69 objects of this invention is to so lower and smooth over-run the starter. In the absence of this .out the idling .of the engine that manoeuvers of provision, the engine would be relatively slow this kind can be carried out with certainty and in getting up to speed, because of the restrainwithout apprehension that the engine may stall ing influence of the very great inertia effects of at a critical moment. the flywheel due to the larger gear ratio. with so the relatively low limit placed on the torque supplied from the engine to the starter by this special clutch arrangement the engine is free impermanently in connection with the engine beyond idling speeds, and accordingly there is included in this invention automatic means whereby the starter is disconnected from the engine whenever the flywheel reaches the maximum desired speed, the connection being automatically re-established whenever the flywheeLspeed falls down to a pre-set minimum.

The control is such that (provided the starte is not overspeeded) the connection of the entire device to the engine may be established or broken at the will of the pilot, so that, when the engine is in normal operation, and until a possible need for a re-start is anticipated, the entire device will be out of action while the connection may be established at any time the pilot wishes to idle his engine or anticipates that it may. stall.

It is pointed out that in a well designed starter mechanism the flywheel will run for many minutes after it has been energized so that the device of this invention may be used for an indefinite number of re-starts after idle periods of several minutes without resource to outside energiz'ation, provided the pilot disconnects his control before stopping the engine. Should he accidentally switchoff the engine without disconnecting the starter, this condition will be at once called to his attention by the refusal of the engine to cease turning'for several .seconds warning him to disconnect the starter if he contemplates utilizing its then existing energy for a start in the next few minutes.

The initial start after prolonged stops will be made in the usual way by energizing the starter from an external power means such as a hand crank or electric motor.

Various other objects and advantages of the invention will be in part obvious from an inspection of the accompanying drawing and a careful consideration of the following particular description and claims of one form of mechanism embodying my invention.

In the drawing:

Figure 1 is a longitudinal section of an inertia type of engine starter in which my present inven-'- tion is embodied.

Figure 2 is a framentary cross section taken on the line 2-2 of Figure l as lookingin the direction indicated by the arrows.

Figure 3 is a fragmentary sectional view taken on the line 3-3 as looking in the direction indicated by the arrows, and discloses the governor weights that control the flywheel speed.

Figure 4 is a detail view of the hand cranking gears engaged with the main starter gear of Figure 1.

With reference to Figure 1, l6 designates the crankcase of an engine to be started to which the starter casing is securedas by bolts -|2, the concentric relation with the engine drive shaft I3 being assured by a pilot I4.

A mechanism common to the inertia type of starter comprises a flywheel i5 rigidly mounted aioa'sso I upon a shaft it having pinion teeth formed thereon for engagement with corresponding teeth of a first reduction gear II. This first reduction gear drives the second reduction pinion l8 through a preset slipping clutch l9 and the pinion engages the main starter gear 20 which is rigidly secured to the internally splined driving hub 2|. The-elements above set forth and described have been used in the past in conjunction with a one-way jaw clutch (not shown) which was engaged with a suitable mating clutch on the engine shaft l3 at the will of the operator when the flywheel I5 has been brought up to speed by a power means external to the engine. Such a power means usually consists of a manually operated hand crank drivably connected to the gear 26; or a high speed electric motor directly connected to the flywheel i5. Detailed information as to the construction of the foregoing may be found in my Patent Nos. 1,561,506, 1,632,539, 1,637,806, and 1,660,953. In the present invention, the preferred construction as shown in the drawing comprises in addition to the parts enumerated above, a self-contained unit 30 having an engine clutch drum 8| and a starter clutch drum 32 engaged respectively with splines on the engine drive shaft i3 and within the main gear hub 2| of the starter. Thus the engine drum ti at all times rotates with the engine, and the starter drum 32 at all times rotates with the spllned hub 2| of the main starter gear. Rigidly secured coaxially within the drum 3| is the clutch sleeve 33 and rigidly secured in the shank of'the starter drum 32 is the pilot tube 34 which rotatably engages the pilot bushing 35 within the sleeve 32. This pilot bearing serves to maintain the drums ti and 32 in true concentric alignment in spite of possible misalignment between the engine shaft i3 and the spline hub 2|, to allow for which a'small amount of play is preferably provided in the fit with the splines on the shaft i3 and in the hub 2|. The relative end location of the two drums is provided for by the central bolt 66 engaged in the disk 31, of the hub 2|, and having a nut 38 engaging a shoulder in the bushing 85. When the starter is removed from the engine the entire clutch unit 30 is withdrawn from the splines on the shaft l3 and may then be removed from the starter by unscrewing the nut 30.

The drum 32 is provided with an external driving lug 36 engaging one end of a coil 40 normally contracted upon the drum 32. An internal coil 4| is normally expanded within the drum 32 and has an out-turned end 42 engaged within akslot in the driving-lug 39. The coil 40 is arranged for expansion of its right hand end into contact with the engine drum 3| and the coil 4| isarranged for contraction of its right hand end into contact with an internal drum 45 by means of the coned extensions 46 and 41 of a control plate 48 which is movable axially by the thrust washer 49 by means of the yoke-lever 50. The internal drum 45 and the clutch drum 32 contain splines with which are respectively engaged al ternated friction clutch plates 5| and 52 held in preset frictional engagement by the dish-washer springs 53 adjustable by the nut 54 screw-threaded on the sleeve 32. The internal. drum 45 is thus drivably connected to the sleeve 33 and thence to the engine shaft H by means of a slipable clutch.

The coils 40 and 4| comprise one-way driving clutches, the hand of helix being such that the coil 40 will lock with the engine drum 3| (when rod 51, which in turn engages the lever 58 and the I aioaeaa expanded by the coned extensions 45, 41 of the control plate 48) to drive the engine from the starter, but will permit the engine to over-run the starter when the former starts to run under its own power. Similarly the helix of the coil 4| is such that it will grip the drum 45 to permit the engine to drive the starter through the slipping clutch 5| and 52, whenever the control plate 48 is moved to contract the 'end of the coil into contact with the drum 45. w

The control yoke 50 is carried by a control shaft 55 having a lever 55 to which is connected with a control handle 59 so that whenever the control handle is pulled to the right the control plate 45 is moved to the left expanding the end of the coil 40 into contact with the drum 3| and contracting the end of the coil 4| into contact withzthe dninr 45,

the partsbeing held in this position by the spring latch 50 engaging a cam 5| on the lever 58. This engagement may be broken at any time by pressing on the control handle 59 which restores the parts to the disengaged position shown.

To prevent over-speeding of the starter mechanism by the engine a centrifugal governor is incorporated, preferably in the flywheel l5. This governor comprises weights 62 radially slidable in grooves in the flywheel hub plate 53'. A pressure plate 54 having a conical rim 5.5 engages the bevel ends of the governor weights 52 under the axial pressures of the spring 65 which surrounds the clutch hub extension 61 and is adjustable by a nut 68. Surrounding this spring is a sleeve 59 integral with the pressure .plate 54 and having the thrust-button I0 engageable with the lever 58.

The flywheel of the starter may be energized independently of the engine as by a conventional hand crank (not shown) engaged with the bevel cranking gear (Fig. 4) which drives the main startergear 20 through the bevel pinion I2 and the cranking gear I3.

The operation of the device is as follows:

Assuming that the parts are in their normal engaging the engine for turning by the starter mechanism. The shock of this engagement is taken by the slipping of the preset main starter clutch I! in the usual way in inertia starters. When the engine starts it is free to over-run the starter drum 32- by virtue of the well-known oneway action of coil clutches such as shown at 40 but the hand. of the inner coil clutch 4|. is such that this locks with the inner drum which is therefore driven at engine speed as long as the.

. action of the spring 65 and, through the cone thrust plate 65, will move the thrust button '10 into contact with the lever 58 which will be operated in clockwise direction relieving the pressure of the coned extension41 of the control plate 48 drum 45 and the engine will cease to drive the starter until such time as the starter speed has decreased to the point at which re-engagement of the coil 4| occurs under the influence of the latch spring acting in opposition to the governor, the latch during the automatic action being in the engaged side of the cam 6|, 1. e. the opposite side to that shown in Fig. 1. This action will continue as long as the control'59 is. left in the pulled out position but the starter can be completely disconnected by pushing on this lever and transferring the cam 5| to the position shown with respect to the latch 50, when the engine is running tacted by the governor pressure plate 64 whenever this is moved an abnormal distance to the right.

The governor plate is restrained to unitary rota tion with the flywheel by the extension-flywheel bolts 16 and accordingly will exert a powerful brake effect upon the flywheel causing slippage of the clutch 5|, and 52 and preventing further increase in flywheel speed, even though for any reason, such as a possible disarrangement of the control connections, the coil 4| has failed to disengage the drum 45. It will be seen that when the control means is in the o crating position. the one-way action of the coil lutches gives a driving connection from the flywheel to the engine through the high torque starter clutch 19 wheneverthe engine tends to fall below starter speed, and through the low torque clutch 5| and 52 whenever the engine is over-running the starter until the governor controldisengages the coil 4|.

Thus the starter will be automatically energized from the running engine whenever the control is maintained in the operative position and will automatically drive the engine whenever it tends to fall below starter speed. In other words, due to the high gear reduction employed, .the very great momentum of the high speed starter flywheel is available as a powerful idling flywheel for the engine, while a restart may be made within several minutes following the switching ofi of'the engine without re-energizing the starter.

Variations may be resorted to within the scope of the invention and portions of the improvements 1 may be used without the others, whilst not departing from the spirit of the invention.

' Having thus described my invention, I claim;

1. In an engine starter, the combination with an engine having a drive shaft, of a flywheel, a gear train, a load limiting clutch in said gear train, a member driven .from the flywheel through said gear train,'means in connection with said member adaptedvto engage and drive the engine shaft when its relative speed as determined by the gear train ratio falls below that of the flywheel, a second load limiting clutch of lesser capacity than the first said clutch, a member driven from the drive shaft and provided with means to engage the gear train and to drive the flywheel through said gear train and said load limiting clutches when the relative speed of the flywheel falls below that of the drive shaft, and means manually operable adapted to make said engaging means effective or ineffective.

2. In anengine starter, the combination with an engine having a drive shaft, of a flywheel, a

gear train, engaging means driven from the flywheel through said gear train and adapted to drivably engage the engine shaft, engaging means driven from the engine shaft and adapted to drivably engage the gear train for the energization of the, flywheel, automatic means controlled by the speed of the flywheel and adapted to cause either of said engaging means to become effective or inefiective, and means manually operable to control the functioning of said automatic means. 3. In an engine starter, the combination with an engine having a drive shaft, of a flywheel, a gear train, a load limiting clutch in said gear train, a normally free engaging means connectable with said gear train and engine shaft and comprising a load limiting clutch of lesser torque capacity than the first said clutch; said engaging means adapted to drivably engage the engine shaft for driving from the flywheel when the relative speed of the shaft falls below that of the flywheel as determined by the gear ratio and to drive the flywheel from the engine shaft when the relative speed of the flywheel falls below that of the shaft, automatic governor means actuated by the speed of the flywheel and adapted to bring into eiTect saidengaging means in the manner stated, and means manually operable to control the functioning of said automatic means.

4. In an engine starter of the character employing an inertia member as a means for supplying starting energy to the engine, the combination with said inertia member of an engine member, and means for maintaining driving engagement between said engine member and said inertia member, said last named means including the latter, and means spaced from said clutch and'tending constantly to hold said one-way clutch in position to resume the cranking in the event theengine speed falls after accelerating sufliciently to overrun said clutch.

v 6. In a starter, the combination with an engine of a'l'iigh speed driving shaft, means including a geartrain and a one-way clutch for drivably connecting said shaft to said engine to start the latter, saidclutch including means tending constantl egto hold'said one-way clutch in position to resume the cranking in the event the engine speed falls after having previously accelerated sufliciently to overrun said clutch, and means including a secondone-way clutch operating to transmit the drive in the reverse direction for the purpose of re-energizing said high speed shaft sufficiently to make such resumption of cranking possible.

7. In a starter, the combination with an engine of a high speeddriving shaft, means including a gear train and a one-way clutch for drivably connecting said shaft to said engine to start the latter, and resilient means tending constantly to hold said one-way clutch in position to resume the cranking in the event the engine speed falls after having previously accelerated sufficiently to overrun said clutch, means including a second one-way clutch operating to transmit the drive in the reverse direction forthe purpose of re-energizing said high speed shaft sumciently to make such resumption of cranking possible, and means for rendering both said one-way clutch devices inoperative, said means being responsive to acceleration of said driving shaft to a predetermined maximum speed.

8. The method of controlling interchange of power between a flywheel and engine crankshaft which includes the steps of interposing a gear train therebetween in such manner as to cause its high speed end to be rotatable with the flywheel and its low speed end rotatable with said crankshaft, disconnecting the gear train from the crankshaft during initial acceleration of the flywheel, then connecting the gear train with the crankshaft to secure initial rotation of the crankshaft and subsequent receleration of the flywheel. v

9. The method of controlling interchange of power between a flywheel and engine crankshaft which includes the steps of interposing a gear train therebetween in such manner as to cause its high speed end to be rotatable with the flywheel and its low speed end rotatable with said crankshaft, disconnecting the gear train from the crankshaft during initial acceleration'of the flywheel, then connecting the gear train with the crankshaft to secure initial rotation of the crankshaft and subsequent receleration of the flywheel, and then releasing the connection between the crankshaft and flywheel when the speed of the latter rises to a predetermined magnitude.

10. The method of controlling interchange. of power between a flywheel and engine crankshaft which includes the steps of interposing multiple part clutch means therebetween in such manner as to cause its high speed end to be rotatable with the flywheel and its low speed end rotatablewlth said crankshaft, disconnecting one part of said clutch means from the crankshaft during initial acceleration of the flywheel, then connecting another part of said clutch means with the crankshaft to secure initial rotation of the crankshaft and subsequent receleration of the flywheel.

11. The method of controlling interchange of power between a flywheel and engine crankshaft which includes the steps of interposing multiple part clutch means therebetween in such manner as to cause its high speed end to be rotatable with the flywheel and its low speed end rotatable with --said shaft, means including linkage operated from said shaft to drivably connect the engine and gear train whenever the engine speed tends to fall below the relative speed of the high speed shaft as determined by the gear train ratioyand resilient means engaging said linkage and adapted to automatically maintain said engagement for the driving of the high speed shaft from the engine whenever the high speed shaft speed drops below a predetermined degree.

13. In combination with an engine crankshaft and an enclosing crank-case, a starter housing mounted on said crank-case, an inertia member disposed within said starter housing, means operable from said inertia member to impart initial rotary movement to said crankshaft and means for causing said crankshaft to be re-startedafter a stop, said re-starting means including connections for temporarily transferring energy from said crankshaft directly to said inertia member and subequently returning the temporarily transferred energy to the crankshaft,

14. In an engine starter, the combination with an engine, of a high speed shaft, means including a gear train'having lowand high speed stages operated from the engine when started to drive the high speed shaft, and means adapted to sever the drive at the low speed stage whenever the high speed shaft is accelerated to a predetermined speed, said severing means comprising an element rotatable at the speedof said shaft.

15. In a starter, the combination with an en: gine, of a high speed shaft, a gear trainhaving low and high speed stages for drivably connecting the high speed shaft to the engine for rotation of the high speed shaft, means for disconnecting the low speed stage from the high speed stage and means rotatable at the speed of, said high speed shaft to operate said disconnecting means when a predetermined fixed speed .of the high speed shaft is reached.

16. In a starter for an internal combustion engine, in combination with the engine, a rotatable inertia member, an overrunning clutch interposed between said, inertia member and engine, means including a gear train operable by I the engine and through the instrumentality of said overrunning clutch for storing energy in the inertia member, and means engageable with said gear train to provide the initial storage of energy in said inertia member for subsequent use in providing initial rotation of the engine.

17. In an engine starter, the combination with an engine member and a driving member, of means including a one-way clutch for transmitting a one-to-one ratio drive from said driving member to said engine member, and means in-' ating with said clutch and tending constantly to hold said one-way clutch in position to resume the cranking in the event the engine speed falls after accelerating sufliciently to overrun said clutch.

19. The method of controlling interchange of power between a starting member and engine crankshaft which includes the steps of interposing a gear train therebetween in such manner as to cause its high speed end to be rotatable with the starting member and its low speed end rotatable with said crankshaft, disconnecting the gear train from the crankshaft during initial acceleration of the starting member, then connecting the gear train with the crankshaft to secure initial rotation of the crankshaft and subsequent receIeration of the starting member.

20. In an engine starter, the combination with unitary device comprising one portion operative with .said flexible member and another portion' operating with said rotatable element, means whereby said portions will be coupled together under normal conditions of load and whereby said portions will become operatively disengaged under abnormal conditions of load, and means for coupling said first-named portion of said unitary device to said flexible member for operation in unison therewith.

21. In an engine starter, the combination with a rotatable element and a coiled spring, of a unitary device comprising one portion operative with said coiled spring and another portion operating with said rotatable element, means whereby said portions will be coupled together under normal conditions of load and whereby said portions will become operatively disengaged under abnormal conditions of load, and means for coupling. said first-named portion of said unitary device to said flexible member, for operation in unison therewith. v

22. In a starter, the combination with an engine, of adriving shaft, means including a clutch for drivably connecting said shaft to said engine to start the latter, and means including a spring cooperating with said clutch and tending constantly to hold said clutch in position to resume the cranking in the event the engine speed falls after accelerating sufficiently to overrun said clutch.

ROLAND CHILTON.

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