US1330985A - Engine-starter - Google Patents

Description

W. L. McGRATH.

ENGINE STARTER.

APPLICATION FILED MAR.27.1919.

Patented Feb. 17, 1920.

WILLIAM L. McGRATH, OF ELMIRA, NEW

COMPANY, OF ELMIRA, NEW YOR YORK, ASSIGNOR TOECLIPSE MACHINE K, A CORPORATION OF NEW YORK.

ENGINE-STARTER.

Specification of Letters Patent.

Patented Feb. 17, 1920.

3 Application filed March 27, 1919. Serial No. 285,569.

To all whom it may concern:

Be it known that I, WILLIAM L. MCGRATH, a citizen of the United States, residing at Elmira, Chemung county, New York, have invented certain new and useful Improvements in Engine-Starters, of which the following is a specification.

My lnvention relates to a starter for an engine such as an internal combustion engine and pertains to the drive or transmission thereof for automatically connecting the starting motor or other power with the member of the engine to be started and for transmitting the power thereto. The object of my invention is to provide a novel, eiiicient .and reliable construction of drive embodying certain novel features with regard to both construction and resulting mode of operation.

My drive is of the -general type known. as the Eclipse-Bendix type of drive which is characterized by the employment of a rotatable member such as a screw shaft driven by a motor or other power and by a driving member mounted on such shaft for longitudinal movement thereof and rotary move ment therewith, which driving member is adapted to either directly or indirectly engage the engine member. In the present instance this driving member is the pinion itself and is itself the part which directly engages the engine member.

The object of my invention is to produce a drive of this general type in which the driving member is capable. of a longitudinal movement on the rotatable member or shaft independent of the longitudinal movement which is enforced by the rotation of the shaft for advancing the pinion into mesh wit-h the engine'member. This independent longitudinal movement is a movement in direction op osite that of the said enforced longitudin movement and takes place in the event that the pinion teeth should strike the fly wheel teeth when such teeth are not in proper register, with the result that the proper cushioning action is provided with a minimum weight of parts moving for that purpose, that is to say, according to this construction, only the light pinion moves and not the entire structure including also the screw shaft and associated parts. Speaking in general terms, this result is accomplished by having the screw threads of the shaft and pinion so construct the drive is of the Before describing the present embodi-.

ment in detail it will be understood that the drive'may beeither direct-driven, as shown, or indirect-driven and also that the driving member may be the pinion itself, as shown, or may be merely the driving or control member of a. separate pinion which itself directly engages the engine member, the broad idea of my invention remaining the same in each case.

As shown the starting motor indicated at A has an extended armature shaft 1 on which is mounted a rotatable shaft 2 which is here in the form of a screw shaft and which is connected to the armature or driving shaft 1 preferably by the coiled driving spring 3. This spring is connected at opposite ends to a driving head or collar 4 on the shaft 1 and to the driving head 5 of the screw shaft, through the medium of the studs or bolts 6 and 7 respectively.

The driving member which is here in the form of a pinion 8 is screw-threaded upon the screw-threaded portion of the shaft 2 and is adapted to be advanced automatically into mesh with the teeth of the fly wheel 9 whenever the screw shaft is rotated and until it contacts the stop nut 10 whereupon such pinion partakes of the rotation of its shaft and rotates and starts the engine. The pinion is automatically demeshed in the well known manner when the engine starts on its own power.

Now referring to the novel construction of the shaft and pinion which constitutes the subject matter of this invention, the screw threads 2 are made very coarse, that is with an extremely wide groove or separation between the threads as clearly shown in Fig. 1.

. pinion are made of much narrower section than the grooves of the shaft, according to the illustrated construction, the threads 8 being only about one-half of the width of the grooves of the screw shaft.

By the provision of screw threads on the shaft and pinion which thus fit loosely, the pinion is permitted a longitudinal backward movement to the left of the screw shaft, which movement is not only independent of its said enforced longitudinal movement but is in an opposite direction. This longitudinal backward movement of the pinion'is a yielding oneby reason of the provision of a light spring 11 interposed between the left hand end of the pinion and an annular spring retainer 12 which is held against the shoulder 5 at the junction between the driving head 5 of the shaft and the screw-threaded portion thereof. This spring tends to hold the forward side of the pinion threads against the rearward sides of the shaft threads but readily yields when the pinion abuts the fly wheel in case of improper meshing. Thus the cushioning action between the driving member or pinion and the fly wheel is provided for with a movement of onl one light part instead. of a movement 0 practically the entire drive.

In addition, the described construction permits of a rotary movement independent of the screw shaft, which movement is advantageous inasmuch as it facilitates the meshing of the pinion and fly wheel teeth whenever such teeth abut. end to end. In this event, the pinion not only yields longitudinally, as ex lained but also rotates slightly but sufliciently to bring itself into proper register with the fly wheel teeth.

I dinally of the rotatable member, and such- I claim:-

1. An engine starter drive including a rotatable member and a driving member mounted directly thereon for longitudinal movement thereof and rotary movement therewith, said rotatable member having means which, when such latter member is rotated, moves'the driving member longitudinally of the rotatable member and such driving member being mounted thereon for longitudinal movement relative to such ro- 'tatable member and its said means and independent of such enforced movement by the rotatable member.

2. An engine starter drive includin a rotatable member and a driving mem er mounted directly thereon for longitudinal movement thereof and rotary movement therewith, said rotatable member having means which, when such latter member is rotated, moves the driving member longitudriving member having a yielding movement longitudinal of the rotatable memher and its said means and independent of its said enforced movement by the rotatable member.

3. An engine starter drive including a rotatable member having screw threads, a screw member screw-threaded thereon, the threads of the rotatable member being separateda distance considerabl in-excess of the width of the threads of t e screw member, to permit of longitudinal movement of the latter.-

An engine starter drive including a rotatable member having screw threads, a screw member screw-threaded thereon, the threads of the rotatable member being separated a distance considerably in excess of the width of the threads of the screw member, to permit of longitudinal movement of the latter, and means for yieldingly holding the threads of the two members in contact.

An engine starter drive including a rotatable member having screw threads, a screw member screw-threaded thereon, the threads of the rotatable member being separated a distance considerably in excess of the width of the threads of the screw memher, to permit of longitudinal movement of the latter, and a spring bearing against the screw .member for yieldingly holding the threads of the two members in contact.

6. An engine starter drive including a rotatable member having screw threads, a. screw member screw-threaded thereon, the threads of the rotatable member being separated a distance considerably in excess of the width of the threads of the screw'memher, to permit of longitudinal movement of the latter, and a spring interposed between a part of the rotatable member and the screw member for yieldinglv holding the threads of the two members in contact.

7. An engine starter including a rotatable screw'shaft, a pinion screw-threaded thereon, the threads of the shaft beingv separated a distance considerably in excess of the threads of the pinion, to permit of longitudina-l movement of the latter.

8. An engine starter drive includin a. rotatable member and a driving mem r mounted thereon for longitudinal movement thereof and rotary movement therewith, said rotatable member having means which, when such latter member is rotated, moves the driving member longitudinally of the rotatable member, and such driving member being mounted thereon for longitudinal movement relative thereto and independent of such enforcedmovement by the rotatable member, and also for rotary movement independent of the shaft.

9. An engine starter drive including a rotatable member having screw threads, a screw member screw threaded thereon, the threads of such membels cooperating to member on the rotatable member independent of its longitudinal movement enforced by the screw action of such rotatable member. and also to permit rotary movement of m-h screw member independent of the rotation of the rotatable member.

10. .\n engine starter drive including a screw shaft. a screw member scrmv-thremled thereon, the threads of the shaft being separated a distance considerably in excess of the width of the threads of the screw member. and the screw member having a longitudinal movement on the shaft in a direction opposite its longitudinal movement as enforced b the. shaft, and also having a rotary movement on such shaft independent of the latter.

WILLIAM L. MCGRATII.

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