US2907215A

US2907215A - Engine cranking apparatus

Info

Publication number: US2907215A
Application number: US744574A
Authority: US
Inventors: William M Hallidy
Original assignee: LEECE NEVILLE CO
Current assignee: LEECE NEVILLE CO
Priority date: 1958-06-25
Filing date: 1958-06-25
Publication date: 1959-10-06
Anticipated expiration: 1976-10-06

Description

Oct. 6, 1959 Filed June 25, 1958 w. M. HALLlDY ENGINE CRANKING APPARATUS 3 Sheets-Sheet 1 INVENTOR.

WILLIAM M. HALLIDY ATTORNEYS i/ m f w Oct. 6, 1959 w. M. HALLIDY ENGINE CRANKING APPARATUS Filed June 25, 1958 3 Sheets-Sheet 2 FIG 4 I r LWL F G] H6. 8 INVENITOR.

WILLIAM M. HALLIDY I ATTORNEYS 1959 w. M. HALLIDY 2,907,215

ENGINE CRANKING APPARATUS Filed June 25, 1958 3 Sheets$heet 3 INVENTOR. W/u/AM M. HALL/DY Arrow/E United States Patent ENGINE CRANKIN G APPARATUS William M. Hallidy, Lakewood, Ohio, assignor to The Leece-Neville Company, Cleveland, Ohio, a corporation of Ohio Application June 25, 1958, Serial No. 744,574

14' Claims. (Cl. 74-6) This invention relates to starting apparatus for internal combustion engines and, more particularly, to a cranking device of the kind having a rotatable and axially shiftable drive pinion releasably engageable with a ring gear of the engine.

This application is a continuation-in-part of my earlier application Serial No. 496,017 filed March 22, 1955.

In engine cranking devices of this kind, the axial move-- ment of the pinion into mesh with the ring gear is often prevented by the occurrence of an abutting engagement between the ends of the pinion teeth and the ends of the teeth of the ring gear. To alleviate this difficulty, cooperating chamfers have been provided on the pinion teeth and ring gear teeth at the adjacent ends of the pinion and ring gear.

In two well-known forms of cranking devices of this kind, two different arrangements of such chamfers have been used in which the two different chamfers of the ring gear have been located on different sides of the teeth thereof. The ring gears of internal combustion engines are, therefore, usually provided by the engine manufacturer with one or the other of these chamfers, depending upon which of the two well-known forms of cranking devices is expected to be used with the engine.

This situation presents a problem for manufacturers of cranking devices because in cranking devices of the previously-known construction produced for use with aring gear having one of such chamfers thereon, those cranking devices will not be usable with ring gears having the other of such chamfers thereon. The manufacturer of cranking devices is thus faced with a need for producing and stocking different forms of such devices in order to be able to fulfill the cranking requirements of different engines.

The present invention meets this situation by providing an engine cranking device of a constructional design which is usable with ring gears having either of the two conventional chamfers, or with a ring gear having no chamfer at all, and which cranking device is capable of automatically clearing a tooth-abutting condition without resorting to the use of a heavy meshing spring or a'powerful solenoid as have been needed in previous forms of cranking devices.

Another object is to provide an engine cranking device of the kind having a rotatable and axially shiftable drive pinion engageable with a ring gear and in which a shift sleeve is effective through axial and helical spline connections to cause an initial rotation of the pinion to facilitate the meshing thereof with the ring gear.

A further object is to'provide such an engine cranking device in which the shift sleeve is movable axially on the shaft of a cranking motor and is effective between the motor shaft and the pinion, such that the axial and helical spline connections cause rotative and axial movements of the pinion in response to the axial movement of the shift sleeve.

Still another object is to provide an engine cranking device of the kind above referred. to in which the axial movement of the pinion is transmitted thereto through taken substantially as indicated by the line a spring means which is adapted to be stressed during the axial movement of the shift sleeve, such that in the occurrence of an abutting engagement between the teeth of the pinion and ring gear and upon the clearing of such abutting engagement by the rotative movement imparted to the pinion, the spring means will actuate the pinion to complete the meshing thereof with the ring gear.

Yet another object is to provide an engine cranking device of the character mentioned above in which the pinion is carried by a drive sleeve or unit and the shift sleeve is disposed between such drive sleeve and the motor shaft, and in which axially-spaced thrust shoulders on the drive sleeve and shift sleeve come into abutting engagement in response to a predetermined extent of axial movement of the latter.

It is also an object of this invention to provide an engine cranking device of the kind above referred to in which the pinion is connected with the drive sleeve through speed-responsive or overrunning clutch means which is automatically disengageable and automatically re-engageable.

It is likewise, an object of this invention to provide an engine cranking device of the kind above indicated in which the pinion is connected with the drive sleeve through torque-responsive clutch means which is automatically disengageable and automatically re-engageable.

Still another object is to provide an engine cranking device of the character referred to above in which the connection between the shift sleeve and the armature shaft of the drive motor is a straight-spline connection and the connection between the shift sleeve and the drive sleeve or pinion is a helical-spline connection, preferably a helical-spline connection having a left-hand inclination or pitch.

As an additional object, this invention provides a shift sleeve for use in an engine cranking device of the kind having a rotatable and axially shiftable pinion, and which shift sleeve has axial spline elements on one side thereof and helical spline elements on the other side thereof.

The invention can be further briefly summarized as consisting in certain novel combinations and arrangements of parts hereinafter described and the claims hereof.

In the accompanying sheets of drawings forming a part of this specification:

Fig. 1 is a partial plan view with portions in section illustrating the cranking motor drive device of this invention and showing the same being used as a starting means for an internal combustion engine;

Fig. 2 is a partial axial sectional view further illustrating the construction of the engine cranking device shown in Fig. 1, the view being taken approximately as indicated by section line 22 of Fig. 3; i

Fig. 3 is a transverse section taken through the device on section line 3-3 of Fig. 2;

Fig. 4 is a partial axial sectional view similar to Fig. 2 but showing a modified form of the cranking devicej Fig. 5 is a partial axial section similar to that of Fig. 4- but showing another modified device;

Fig. 6 is a fragmentary transverse section somewhatv diagrammatic in form and taken substantially as indicated by sectionline 6-6 .of Fig. 1 to further illustrate the cooperation of the drive pinion with the ring gear;

Fig. 7 is a partial viewof the pinion and ring gear 77 of Fig. 6

and showing one form of tooth chamfer; 1

Fig. 8 is a partial view of the ring gear and pinion similar to that of Fig. 7 but showing another form of tooth chamfer; and

particularly set out in form of the cranking Fig. 9 is a partial axial section similar to those of Figs. 4 and 5 but showing a further modification of the cranking device.

As representing one practical embodiment of the invention, Figs. 1, 2 and 3 show the novel cranking device as being carried by a mounting bracket 11 for mounting on an internal combustion engine in adjacent relation to a so-called ring gear 12, such as a cranking gear carried by the flywheel 13 of the engine. The cranking device 10 comprises, in general, an electric driving motor 14 having an armature shaft 15, a rotatable and axially shiftable drive pinion 16 releasably engageahle with the ring gear 12, and means flexibly connecting the pinion with the armature shaft for actuation by the latter.

The driving motor 14 may be a conventional form of starter motor having a frame 17 which is suitably connected with the bracket 11 for mounting the motor thereon. The motor 14 is here shown as having an armature 18 rotatable in the frame 17 and carried by the armature shaft 15. The frame of the motor 14 includes an end plate 19 through which the armature shaft extends and which has a central bearingportion 20 for this shaft.

The armature shaft 15 includes a relatively reduced shaft portion 22 at its outer end which is rotatably supported in an outboard bearing 23 of the mounting bracket 11. A stop collar 24 is mounted on the shaft portion 22 for a purpose to beexplained hereinafter and is positioned adjacent the outboard bearing 23 by the snap ring 25. The pinion 16 is mounted on the. shaft portion 22 so as to be rotatable and axially shiftable thereon. The pinion is here shown as being mounted on the shaft portion 22 by means of the bushing 26.

Adjacent the junction of the shaft portion 22 with the full-size portion 15 of the armature shaft 15, the armature shaft is provided with a helical spline 28 formed by a group ofhelically extending spline teeth 28 The normal rotation of the armature shaft 15 produced by energization of the motor 14 is in the direction indicated by the arrow 29. Since the helical spline 28 is connected with, or formed on, the armature shaft 15, it is, likewise, rotatable by the motor 14 in the direction of the arrow 29. The helical spline '28 is here shown as having a right-hand pitch.

The pinion 16 is flexibly connected with the armature shaft 15 through a coupling means comprising a drive sleeve 31 connected with the pinion, and a shift sleeve 32 located between the drive sleeve 31 and the armature shaft 15. The pinion 16 is here shown as being an integral part of the drive sleeve 31, although it can be connected therewith through clutch means, as shown in Figs. 4 and 5 and described hereinafter.

The shift sleeve 32 and the drive sleeve 31 are both disposed in a surrounding coaxial relation to the armature shaft 15. The shift sleeve 32 is provided on the inside thereof with a helical spline 33 formed by a group of internal helical spline teeth 33 which have a meshing engagement, or screw thread cooperation, with the helicalspline teeth 28 of the armature shaft 15. The shift sleeve 32 is provided on the outside thereof with an axial spline 34 formed by a group of straight or axially extending spline teeth 34*.

The drive sleeve 31 has an axial socket 36 therein into which the adjacent end of the shift sleeve 32 telescopically extends. The telescoping end of the shift sleeve 32 has an end face forming an annular thrust shoulder 37 which co-operates with an annular thrust shoulder 38 formed by the inner end wall of the socket 36, but is rsigrmally spaced therefrom by the intervening axial space The drive sleeve 31 is provided on the inside thereof w th a straight or axial spline 40 formed by a group of axially extending internal spline teeth 40. This internal axial spline 40 of the drive sleeve 31 is in meshed engagement with the external axial spline, 34, of the shift 4. sleeve 32. The co-operating external and internal

axial splines

34 and 40 are slidable on each other duringrelative axial movement between the

sleeves

31 and 32.

Axial movement can be imparted to the shift sleeve 32 by means of a shift collar 43 which is secured to, or formed on, this sleeve. In this instance, the shift collar 43 is in the form of a ring mounted on the shift sleeve 32 by means of the snap ring 44 and having an external annular groove 45.

The axial movement applied to the shift sleeve 32 through the collar 43 is produced by an actuating lever 46 swingably mounted on a pivot shaft 47 of the mounting bracket 11 and having a forked inner end 48 engaged in the groove 45 of the shift collar. The outer end of the lever 46 is provided with a handle element, or the like, 4? for the application of actuating force to this lever.

Axial movement imparted to the shift sleeve 32 is transmitted to the drive sleeve 31 through a compression spring 5t) located in surrounding relation to the shift sleeve and disposed between the shift collar 43 and the adjacent end of the drive sleeve. Complete separation of the drive sleeve 31 from the shift sleeve 32 under the expansive action of the spring 50 is prevented by a snap ring 51 which is mounted on the shift sleeve adjacent the thrust shoulder 37 thereof and which is engageable with the inner ends of the internal spline teeth 43 of the drive sleeve, as shown in Fig. 2.

From the construction of the cranking device 10 as thus far described, it will be seen that when axial movement toward the right is imparted to the shift sleeve 32 by the shift collar 43, axial movement in the same direction will be transmitted to the pinion 16 through the compression spring 50 thereby moving the pinion axially toward the ring gear 12. if the teeth of the pinion move immediately into mesh with the teeth of the ring gear,

the pinion will thereuponassume an engaged position corresponding with its broken-line showing 16 in Fig. 1. To explain in greater detail the action which takes place duringlsuch a direct meshing of the pinion 16 with the ring gear 12, it is pointed out that by the time the pinion has moved part-way into mesh with the ring gear, the sides of the pinion teeth will be pressed against the sides of the ring gear teeth. This pressure between the sides of the pinion and ring gear teeth will resist further axial meshing movement of the pinion but such resistance will be overcome and the pinion will be shifted axially into full mesh with the ring gear by the shoulder 37 coming into engagement with the shoulder 38.

During this movement of the pinion 16 axially into mesh with the ring gear 12, the latter is relatively stationary and initially resists the rotation of the pinion. Since the partially meshed pinion is thus held against rotation by the ring gear, the continuing axial movement of the shift sleeve 32 will cause the helical spline 33 of the latter to react against the spline teeth 28 of the armature shaft 15 and rotate the armature shaft in a backward direction, that is, in a direction opposite to that indicated by the arrow 29. This backward rotation of the armature shaft 15' can readily take place at this time inasmuch as the motor 17 has not yet been energized.

As the pinion 16 reaches its position 16 of full engagement with the ring gear 12, it abuts against the stop collar 24. During the above-described axial movement of the pinion 16, the lever 46 is being swung toward its broken-line position 46 The lever 46 carries a thrust screw 53 which engages and actuates a plunger 54 of a starting switch 55 controlling the energization of the starter motor 14. The final portion of the swinging movement of the lever 46, which results in the above-tie scribed full-mesh engagment of the pinion 16 with the ring gear 12, causes the switch plunger-54 to be actuated to thereby close the starting switch 55 and energize the motor.

The motor 3,4. thereupon rotates the pinion. 16 in the the lever 46, this lever is returned direction of the arrow 29 while the pinion is being held in mesh with the ring gear 12 by the cooperation of the shoulder 37 with the shoulder 38. The cranking torque thus applied to the ring gear 12 by the pinion 16 will be in accordance with the direction of rotation indicated in Fig. 7 by the

arrows

56 and 57 of the pinion and ring gear, the rotation indicated by the arrow 57 for the ring gear being its given or normal direction of rotation.

Upon release of the actuating force being applied to to its full-line position of Fig. l by the action of a torsion spring 52 disposed around the pivot shaft 47. The torsion spring has one end thereof suitably anchored on the housing 11 and its other end 52 engaging the arm of the shifter fork 48. This is accompanied by an axial return movement of the shift sleeve 32 and the collar 43 toward the left along the armature shaft 15 by the compression spring 50. This return axial movement of the shift sleeve 32 causes the snap ring 51 to engage the inner ends of the axial spline teeth 40 of the drive sleeve 31 to thereby pull the pinion 16 away from the ring gear '12. The swinging of the lever 46 toward its full-line position also releases the switch plunger 54, whereupon the starting switch 55 causes deenergization of the starter motor 14.

When the axial movement of the drive pinion 16 toward the ring gear 12 by the above-described actuation of the lever 46 results in a condition of abutting engage ment of the ends of thepinion teeth 62 with the ends of the ring gear teeth 59, the axial movement of the pinion is temporarily stopped. Thereupon, the succeeding axial movement of the shift sleeve 32 occurring while the starter motor 14 is deenergized and the armature shaft 15 is initially stationary, results in rotation of the shift sleeve 32 about the armature shaft in a direction opposite to that represented by the arrow 29.

This rotation of the shift sleeve 32 is caused by the helical spline connection 28 and imparts a clearing rotation to the pinion 16 in the same direction through the axial spline connection 40. This direction of clearing rotation for the pinion 16 is indicated by the broken-line arrow 58 of Fig. 7 and causes the abutting engagement of the pinion teeth with the ring gear teeth to be cleared, whereupon the pinion is shifted quickly into full-mesh engagement with the ring gear by the action of the compression spring 50. By the time that the pinion reaches its full-mesh position, the major portion of the space between the

shoulders

37' and 38 will have been taken up and, during the delivery of cranking torque to the gear 12, the pinion will be prevented from disengagement from the gear by the cooperation of these shoulders.

Fig. 7 shows the teeth 59 of the ring gear 12 as having a chamfer 60 thereon at the ends thereof nearest the pinion. The chamfer 60 is formed on the ring gear teeth 59 on the trailing side thereof with respect to the given or normal rotational direction indicated for the ring gear by the arrow 57. A similar chamfer 61 is provided on the pinion teeth 62 but is located on the leading side of the pinion teeth with respect to the direction of the driving rotation of the pinion, as indicated by the arrow 56. The chamfer 60 of the ring gear 12 represents a conventional form of chamfer known in the art as a Dyer form of ring gear chamfer.

From Fig. 7, it will be seen that the clearing rotation imparted to the pinion 16 by the action of the helical spline connection 28 will be in the direction of the broken-line arrow 58 and, as soon as the pinion has been.

rotated sufliciently to clear the abutting condition, the pinion teeth will be moved into mesh with the ring gear teeth and this movement will be facilitated by the

chamfers

60 and 61. In thus clearing'a tooth-abutting condition, the maximum amount of clearing rotation needed to be imparted to the pinion will be the width of one tooth inasmuch as when this amount of clearing rotation has taken place, the chamfer 61 will then slide down the chamfer 60 causing the pinion teeth 6 to be directed into meshed engagement with the ring gear teeth.

Fig. 4 of the drawings shows an engine cranking device 65 which is similar to the cranking device 10 and functions'in a similar manner. The cranking device 65, however, employs a drive unit 66 for connecting the pinion 16 with the drive sleeve31 and which drive unit embodies both a speed-responsive clutch means and a torque-responsive clutch means.

The drive unit 66 comprises an annular housing member 67 having

coaxial recesses

68 and 69 extending thereinto from opposite ends thereof. The pinion 16 does not have a fixed connection with the housing 67 but carries an annularly grooved collar 70 which extends into the recess 68 and is retained therein by a snap ring 71. Likewise, the drive sleeve 31 does not have a fixed connection with the housing '67 but carries a collar 72 which extends into the recess 69. The connection between the housing 67 and the pinion 16, as provided by thesnap The adjacent ends of the

collars

70 and 72 are spaced apart in the recess 68 and are separated by a clutch ring 73 disposed therebetween. The collar 70 and the clutch ring 73 have co-operating

clutch teeth

74 and 75 thereon of a ratchet-like form and which are normally maintained in driving engagement by a compression spring 76 disposed around the shaft portion 22. The clutch ring 73 is axially shiftable on the shaft portion 22 in opposition to the spring 76 for automatically releasing the driving connection between the

teeth

74 and 75. V

The clutch connection providing by the

teeth

74 and 75 constitutes an overrunning or speed-responsive clutch which is automatically releasable and permits the pinion 16 to be driven by the ring gear 12 under certain conditions, without causing such rotation of the pinion to be transmitted to the armature shaft 15. When the abnormal The'adjacent ends of the collar 72 and the clutch ring 7 73 have cooperating sets of

clutchteeth

78 and 79 thereon which are normally maintained in driving engagement by a spring means, such as a group of spring washers 81) disposed in the recess 69 and effective between the collar 72 and a thrust shoulder formed by an internal snap ring 81. The cooperating

clutch teeth

78 and 79 constitute a torque-responsive overload release which interrupts the drive connection to the pinion 16 and permits the armature shaft 15 to rotate relative to the pinion when an abnormal condition exists, such as a condition in which the .ring gear 12 is locked against rotation. When the abnormal condition preventing rotation of the ring gear 12 is removed, the spring means automatically causes engagement of the

clutch teeth

78 and 79 to re-establish the drive connection between the armature shaft and the pinion 16.

The formation of the

clutch teeth

78 and 79 is such that a space 82 is provided of sufiicient axial width to permit shifting of the clutch ring 73 toward the left to allow the clutch teeth 74 to ratchet over the clutch teeth 75 when the above-described abnormal condition occurs to cause rotation of the pinion 16 by the ring gear 12.

Fig. 5 of the drawings shows an engine cranking device 85 which is similar to the cranking device 65 of Fig. 4, but which is of a constructional design for use with another conventional form of ringgear chamfer. The parts of the cranking device 85 which correspond with parts of the cranking device 65 are designated by the same reference characters.

The drive pinion 16 of the cranking device 85 cooperates with the ring gear 12 but these gear members are provided, respectively, withchamfers 86 and 87 which are shown in Fig. 8 and which represent another conventional form of chant-fer known the art as a Bendix chamfer. The given or normal direction of rotation for the ring gear 12 during the cranking operation again is indicated by the arrow 57, and the direction of driving rotation of the pinion is indicated by the full-line arrow 56. The rotary movement of the pinion 16 for clearing a tooth-abutting condition occurring. between the pinion and ring gear is indicated by the broken-line directiondarrow 88.

The cranking device 85 dilfers from the cranking device 65 in that the helical spline connection 28 is located between the drive sleeve 31 and the shift sleeve 32, and the axial or straight spline connection 40 is located between the drive sleeve 32 and the armature shaft 15. This location for the helical and axial splines on the outside and inside respectively, of the shift sleeve 32 is the reverse of the location of these splines on the shift sleeve of the cranking device 65, although the helical spline elements 28 of the cranking device 35 have the same directional inclination or pitch as the helical spline elements 28 of the cranking evice 65, namely a righthand inclination or pitch. 7

The operation of the cranking device 85 is substantially identical with that described above for the cranking devices 1t and 55, with the exception that the rotary movement which is imparted to the pinion 16 by the helical spline connection .25 upon the occurrence of a tooth-abutting engagement between the pinion and ring gear, is in the opposite direction from the clearing rotation imparted to the pinion in the cranking devices and 65, that is to say, is a clearing rotation in the direction of the broken-line arrow 88 which is in the same direction as the normal cranking rotation of the pinion.

The cranking device provided by this invention can accordingly be rendered suitable for proper functioning with a ring gear having either of the two conventional forms of chamfer by merely using in the cranking device a helical spline connection 28 which will produce a clearing rotational movement of the pinion 16 corresponding with that which will cooperate in the desired manner with the chamfer carried by the ring gear.

Thus the cranking devices ill and 65 of Figs. 2' and 4 having a right-handhelical spline on the inside of the shift sleeve 32, are usable with a ring gear 12 carrying a Dyer chamfer (represented in Fig. 7), provided that a pinion having the tooth chamfer 61 is employed and the driving torque of the cranking motor 17 is in the direction indicated by the arrow 29. These same cranking devices 1%) and 65 would be usable with a ring gear carrying a Bendix chamfer (represented in Fig. 8) by employing a pinion having the tooth chamfer 87 thereon, and by using either a shift sleeve 32. having a left-hand internal helical spline or a cranking motor which delivers torque in a rotational direction opposite to that indicated by the arrow 29. This latter form of cranking motor is frequently used with marine engines.

The modified cranking device 85, shown in Fig. 5 and having the right-hand helical spline connection 28 between the drive and shift

sleeves

31 and 32, and an axial or straight spline connection 40 between the armature shaft and the shift sleeve 32, is usable with a ring gear 12 carrying a Bendix chamfer 86, provided that a pinion 16 having a Bendix chamfer 87 is employed and the driving torque of the cranking motor 14 is in the direction of the arrow 29. In the operation of the device 85, the clearing rotation of the abutting pinion teeth will be in the same direction as the gear 12, as is indlcated by the broken line arrow 88 of Fig. 8.

Fig. 9 shows another modified cranking devvice 85" which is similar to the cranking device 85 of Fig. 5 in that it has a helical spline connection 28 between its drive and shift

sleeves

31 and 32 and an axial or straight spline connection 49 between the armature shaft 15 and the shift sleeve 32. In this modified cranking device 85*, the

a helical spline connection 28 has a left-hand inclination or pitch. The cranking device is usable with a ring gear 12 having a Dyer form of chamfer 60, provided that a pinion 15 having a Dyer charnfer 61 is employed and the driving torque of the cranking motor 14 is in the direction of the arrow 29. In the operation of the device 85 the clearing rotation of the abutting pinion teeth will be in a direction opposite to that of the gear 12, as is indi cated by the broken line arrow 58 of Fig. 7.

From the accompanying drawings and the foregoing detailed description, it will now be readily understood that this invention provides engine cranking apparatus embodying a novel drive means for the pinion which renders the cranking apparatus applicable to ring gears having eitherv of two conventional forms of tooth chamfers, or applicable to a ring gear having no chamfer at all. It will now be seen further that this novel cranking device embodies a shift sleeve having axial and helical spline elements on opposite sides thereof, such that the shift sleeve will transmit rotary driving movement to the pinion and will also impart a rotational clearing movement to the pinion for automatically clearing a tooth-abutting engagement with the ring gear whenever such an abutting condition occurs. Additionally, it will be seen that the shift sleeve co-operates with the pinion for maintaining the latter in mesh with the ring gear during the that the invention is not to be regarded as being limited correspondingly in scope, but includes all changes and modifications coming within the terms of the claims hereof.

Having described my invention, I claim:

1. In cranking apparatus for an engine having a ring gear; a drive motor having a shaft extending adjacent said gear; a drive sleeve surrounding said-shaft; a pinion rotatable and axially slidable on said shaft; a housing carried by said drive sleeve; connecting means between said housing and pinion providing for relativerotation therebetween and for the application of axial movement and thrust to the pinion; a shift sleeve between said drive sleeve and shaft; said drive sleeve, said shift sleeve and said shaft comprising a group of three coaxial members; coacting elements defining an axial spline connection between a first pair of said members; coacting elements defining a helical spline connection between a second pair of. said members; a shift collar connected with said shift sleeve for imparting axial movement to the latter; a compression spring surrounding said shift sleeve and effective between said collar and said drive sleeve for imparting axial movement to the latter for advancing said pinion into engagement with said gear; said axial spline connection being effective to transmit cranking rotation to said pinion; said helical spline connection being efiective to cause a tooth-clearing meshing rotation of said pinion in response to the axial movement of said shift sleeve by said collar; and automatically disengageable and automatically re-engageable clutch means in said housing and having a normally engaged condition connecting said drive sleeve with said pinion. v

2. In a cranking apparatus for an engine having a cranking gear; a drive motor having a shaft extending adjacent said gear; a drive sleeve surrounding said shaft; a pinion rotatable and axially slidable on said shaft; a housing carried by said drive sleeve; connectingv means between said housing and pinion providing for relative rotation therebetween and for the the application of axial second pair of said members; a shift collar connected with said shift sleeve for imparting axial movement to the latter; a compression spring surrounding said shift sleeve and effective between'said collar and said drive sleeve for imparting axial movement to the latter for advancing said pinion into engagement with said gear; said axial spline connection being effective to transmit cranking rotation to said pinion; said helical spline connection being effective to cause a tooth-clearing meshing rotation of said pinion in response to the axial movement of said shift sleeve by said collar; and automatically disengageable and automatically re-engageable speed responsive clutch means'in said housing and having a normallyengaged condition connecting said drive sleeve with said pinion; said speed responsive clutch means being effective to drivingly disengage said pinion from said drive sleeve when the speed of said pinion exceeds the speed of the cranking rotation of said shaft. I

3. In cranking apparatus for an engine provided with a cranking gear having a given direction of operating rtation; a motor having a shaft extending adjacent said gear and operable in a given direction of cranking rotation; a rotatable pinion shiftable axially along said shaft; a drive 1 sleeve surrounding said shaft; a housing carried by said drive sleeve; connecting means between said housing and pinion and providing for relative rotation therebetween and for the application of axial movement and thrust to the pinion; a shift sleeve disposed between said drive sleeve and shaft; coacting elements defining an axial spline connection between said shift sleeve and said shaft; coacting elements defining a helical spline connection between said drive sleeve and said shift sleeve; and means for moving said sleeves and pinion axially of said axial'spline connection and shaft for advancing said pinion into engagement with said gear; said helical spline connection being effective to cause rotation of said pinion for clearing a tooth-abutting condition occurring between said pinion and gear; the directional pitch of said helical spline connection in relation to the cranking rotation of said shaft being such as to produce a clearing rotation of the tooth-abutting portion of said pinion in a direction opposite to said given direction of rotation of said gear.

4. Cranking apparatus as defined in claim 3 includes normally-engaged overrunning clutch in said housing, and wherein said pinion is also connected with said drive sleeve through said overrunning clutch such that the pinion can overrun said drive sleeve.

5. In starting apparatus for an engine provided with a cranking gear having a given direction of operating rotation and whose teeth have a chamfer on the trailing side thereof; a motor having a shaft operable in a given direction of cranking rotation; a pinion rotatable on said shaft and shiftable axially therealong for engagement with said gear; means for flexibly connecting said pinion with said shaft comprising a drive sleeve surrounding said shaft and a shift sleeve disposed between said shaft and said drive sleeve; a housing carried by said drive sleeve; connecting means between said housing and pinion and providing for relative rotation therebetween and for the application of axial movement and thrust to the pinion; coacting elements defining an axial spline connection between said shift sleeve and said shaft; coacting elements defining a helical spline connection between said drive sleeve and said shift sleeve; means for moving said shift sleeve axially along said shaft; and spring meansadapted to be loaded by the axial movement of said shift sleeve for imparting axial movement to said drive sleeve and pinion in a direction to engage said pinion with said gear; said helical spline connection being effective to cause rotation of said pinion for clearing a tooth-abutting condition occurring between said pinion and gear; the directional pitch of said helical spline connection in relation to the cranking rotation of said shaft being such as to produce a clearing rotation of the tooth-abutting portion of said pinion in a direction opposite to said given direction of rotation of said gear.

and which 6. In s'tarting apparatus for an engine provided witlr a cranking gear having a given direction of operating rotation and whose teeth have a chamfer on the trailing side thereof; a cranking motor having a shaft; a pinionrotatable on said shaft and shiftable axially therealong for engagement with said gear; said shaft having a clockwise cranking rotation as viewed from the pinion end thereof; a shift sleeve movable on said shaft; "coacting elements providing an axial spline connection between said shift sleeve and said shaft; a drive sleeve surrounding said shaft and movable relative to said shift sleeve; means connecting said drive sleeve and pinion and providing for relative rotation therebetween andfor the application of axial movement and thrust to the pinion;

coacting elements providing a helical spline connection between said shift sleeve and said drive sleeve; means for moving said shift sleeve axially of said shaft; and spring means for causing axial movement of said pinion toward said gear in response to the axial movement of said shift 7 sleeve and adapted to be stressed upon the occurrence of a tooth-abutting engagement of the ends of the pinion teethwith the ends of the gear teeth; said helical spline connection having a left-hand thread pitch and being effective to cause a clearing rotation of the tooth-abutting portion of said pinion in a direction opposite to said given direction of rotation of said gear for clearing said abutting engagement and said'spring means being effective to complete the movement of said pinion into mesh with said gear upon the clearing of said abutting engagement.

7. Engine starting apparatus as defined in claim 6 and which includes toothed clutch means connecting said drive sleeve with said pinion; said clutch means being automatically disengageable and automatically re-engageable and comprising a normally engaged torque responsive clutch means and a normally engaged speed responsive clutch means:

8.. In cranking apparatus for an engine provided with a cranking gear having a given direction of operating rotation and whose teeth have a chamfer on the trailing side thereof; a drive motor having a shaft extending adjacent said gear and operable in a given direction of cranking rotation; a drive sleeve surrounding said shaft; a pinion rotatable on said shaft and shiftable axially therealong for engagement with said gear; means connecting said drive sleeve and pinion and providing for relative rotation therebetween and for the application of axial movement and thrust to the pinion; a shift sleeve between said drive sleeve and shaft; coacting elements defining an axial spline and said shaft; coacting elements defining a helical spline connection between said mined relative axial movement between said sleeves; and

a compression spring surrounding said shift sleeve and effective between said collar and said drive sleeve for imparting axial movement to the latter for advancing said pinion into engagement with said gear; said axial spline connection being effective to transmit cranking rotation from said shaft to said pinion through said sleeves; said helical spline connection being effective to cause a toothclearing rotation of said pinion in response to axial movement of said shift sleeve relative to said drive sleeve to facilitate the movement of said pinion into mesh with said gear; said helical spline connection having a directional pitch in relation to the cranking rotation of said shaft such that said tooth-clearing rotation of the tooth-abutting portion of said pinion is in a direction opposite to said given direction of rotation of said gear.

9. Cranking apparatus as defined in claim 1 wherein said clutch means is a torque responsive clutch means comprising automatically disengageable and automatically re-engageable co-operating clutch members effective to.

connection'between shift sleeve f effective to drivingly disengage said pinion from said drive sleeve when the speed of said pinion exceeds the speed of the cranking rotation of said shaft and the other set of said clutch teeth being etfective to drivingly disengage said pinion from said drive sleeve in response to a torque overload condition.

11. In cranking apparatus for an engine having a ring gear provided with a chamfer on one side of the teeth thereof to facilitate pinion engagement; a drive motor having a shaft extending adjacent said gear; a drive sleeve surrounding said shaft; a pinion rotatable and axially slidable on said shaft; a housing carried by said drive sleeve; connecting means between said housing and pinion and providing for relative rotation therebetween and for the application of axial movement and thrust to the pinion; a shift sleeve between said drive sleeve and shaft; said drive sleeve, said shift sleeve and said shaft comprising a group of three coaxial members; coacting elements defining an axial spline connection between said shaft and said shift sleeve; coacting elements defining a helical spline connection between said shift sleeve and said drive sleeve; a shift collar connected with said shift sleeve for imparting axial movement to the latter; a compression spring surrounding said shift sleeve and efiective between said collar and said drive sleeve for imparting axial movement to the latter for advancing said pinion into engagement with said gear; said axial spline connection being effective to transmit cranking rotation to said pinion; said helical spline connection having a directional pitch effective to cause a tooth-clearing rotative cooperation of said pinion with said chamfer in response to the axial movement of said shift sleeve by said collar; and clutch means in said housing providing an operative connection between said drive sleeve and said pinion and being in a normally-engaged condition for transmitting cranking torque to the pinion; said clutch means being subject to disengagement only upon the occurrence of a predetermined operating condition of the cranking apparatus after the pinion has been moved into mesh with said gear.

12. Cranking apparatus as defined in claim 11 wherein said clutch means is a speed responsive clutch means comprising automatically disengageable and automatically reengageable co-operating clutch members effective to drivingly disengage said pinion from said drive sleeve when the speed of said pinion exceeds the speed of the cranking rotation of said shaft.

l3. cranking apparatus as defined in claim 11 wherein said clutch means is both a speed responsive and a torque responsive clutch means comprising two sets of automatically disengageable and automatically re-engageable co-operating clutch teeth; one set of said clutch teeth being effective to drivingly disengage said pinion from said drive sleeve when the speed of said pinion exceeds the speed of the cranking rotation of said shaft and the other set of said clutch teeth being effective to drivingly disengage said pinion from said drive sleeve in response to a torque overload condition.

l4. cranking apparatus as defined in claim 11 wherein said chamfer is on the trailing side of the ring gear teeth and the operating rotation of said shaft is a clock wise rotation when the shaft is viewed from the pinion end thereof; and wherein the directional pitch of said helical spline connection is a left-hand pitch.

References (Zited in the file of this patent UNITED STATES PATENTS 1,721,241 Whitney July 16, 1929 1,892,056 Jackson Dec. 27, 1932 2,745,289 Miller May 15, 1956 2,841,988 Sabatini July 8, 1958