US2103233A

US2103233A - Engine starter

Info

Publication number: US2103233A
Application number: US118535A
Authority: US
Inventors: James A Charter
Original assignee: CHARTER DRIVE Inc
Current assignee: CHARTER DRIVE Inc; Martin Marietta Corp
Priority date: 1936-12-31
Filing date: 1936-12-31
Publication date: 1937-12-28
Anticipated expiration: 1954-12-28

Description

Dec. 28, 1937.

J. A. CHARTER ENGINE STARTER Filed Dec. 51, 1936 Patented Dec. 28, 1937 UNITED STATES PATENT OFFICE ENGINE STARTER Illinois Application December 31, 1936, Serial No. 118,535

11 Claims.

The present invention relates generally to engine starters and more particularly to springs for use in starters wherein the spring forms a yieldable driving connection and operatively functions to cause movement of a pinion or driving member.

The present invention concerns the general type of engine starters wherein a coiled spring structure is coupled with a pinion adapted to be moved into and out of engagement with a driven gear of the engine or motor, the spring structure cooperating with a projecting member, sometimes referred to as a tracker, which is movable between the convolutions of the spring 1 structure, in which device the tracker, in response to rotation of the starting motor, automaticallymoves the pinion into operative position to drive the engine.

In the present type of starter the energy to drive the engine is thus transmitted from the tracker to the end of the spring and resiliently therethrough to the pinion. Normally the spring is secured in some measure to the pinion at one end thereof, the assembly being relatively free to move axially, and the other end of the spring being free except when it resides against the tracker in driving position and the pinion is in mesh with the motor gear.

It is, moreover, important that the interior diameter of the spring be of greater dimension than any interior axial support for the spring or pinion since the resilience of the spring necessitates clearance for radial contraction. Furthermore the spring connection with the pinion is primarily for the purpose of transmitting power thereto and conventionally takes a form adapted to ready replacement rather than positive and rigid support of the spring. It is thus apparent that, in a structure of the instant type, the spring is subject to vibration or rattling and general dislocation from its preferred axial position.

It is a purpose of the present invention, therefore, to provide a structure wherein the spring will be more or less positively and rigidly maintained in a preferred axial position with respect to the starter and which will be maintained against normal rattling, vibration or displacing forces.

Another object of this invention is to provide an engine starter spring structure which will enhance the wrapping clutch action adjacent the edges of the spring when employed in conjunction with a central drive shaft unit.

Numerous other objects and advantages will be apparent from a consideration of the following specification anddrawing which discloses a few devices constructed in accordance with the principles of the present invention and in which- Figure 1 is an elevational view of a starter constructed in accordance with the present inven- 5 tion, portions being shown in section;

Figure 2 is a perspective view of a starter, as shown in Figure 1;

Figure 3 is an end elevation taken from the righthand end, as viewed in Figure 1; 10

Figure 4 is an end elevation taken from the lefthand end, as viewed in Figure l; and

Figure 5 is a sectional elevation taken through an alternative preferred form of spring.

Referring now to the drawing more in detail wherein like numerals have been employed to designate numerous parts throughout the various figures, it will be seen thatin Figures 1 to 4 inclusive there is disclosed a preferredembodiment of the invention, a starter mechanism '20,

being disclosed in these figures bythe numeral It] and a rotary driving structure designated generally by the numeral !2.- The rotary driving structure comprises a driven pinion l4 and a sleeve or drum IB- formed integrally with the pinion. This structure is mounted for rotation upon a motor shaft 18 which connects with any suitable starting motor, preferably an electric starting motor (not shown) of the type employed to start gasoline engines or the like. 30"- A driving spring structure 20 comprising multiple or double strand convolution for coupling with the sleeve section-J6 through the agency of hook portions 22 diametrically positioned, is provided at free extremities of'the spring strands. These 35' drive shaft l8 mentioned above, a sleeve section 30 which is driven by the motor shaft I8 through the agency of a suitable key and key-way (not 50 shown).

The spring, shown for illustrative purposes, 7 includes a continuous strand of wire of relatively flat continuous material having a generally cylindrical configuration. The loop end 32,'form- 55- 7 ing one extremity of the coil, is free from any positive securement to the sleeve 30, the two strands extending helically therefrom in parallel directions. The axial spacing of the strands forms a helical track or way 34 adapted to be engaged by a suitable tracking member for shifting the spring and the pinion longitudinally for causing rotation thereof. At a point midway of the axis of the spring the spacing of the convolutions is diminished with the result that the strands reside closely adjacent each other, as indicated at 36 in Figure 1. The free extremities of the two strands do not terminate at the same point but form the hooks 22 at diametrically opposite points. Thus, the strand, which at the hook end of the structure constitutes the inner strand, continues helically and circumferentially beyond the free extremity of the outer strand to present a second diametrically positioned hook or coupling means. The cylindrical spring coil 20 has an inside diameter greater than the diameter of the sleeve 30 with the re sult that the spring is spaced radially from the outer surface of the sleeve. It will be obvious that such clearance is practically essential in the operation of the device since it permits further coiling or expansion of the spring.

Referring particularly to Figures 3 and i, how ever, it will be noticed that the strands at both extremities are deformed inwardly to a point adjacent the sleeve. Referring to the hook end of the spring, as shown in Figure 3, the two strands are deformed relatively sharply invhrd- 1y, as shown at 38, from the normal inside radius of the coil, as indicated at 4|). The opposite extremity of the coil, namely, the loop end 32, is similarly offset radially inwardly of the interior of the coil, as indicated at 42 in Figure 4. In the instant embodiment the inward deformations of the coil occur in a relatively short arc, thereby permitting efiective resilient spring action along substantially the entire length of the convolutions. Thus, in the preferred embodiment shown in Figures 1 to 4, the entire extent of each inwardly deformed portion of the spring constitutes less than degrees: of a convolution. If substantial portions of the spring were deformed inwardly and in contact with the sleeve 36, contraction or stretching of the spring along this area would be hindered.

In use the spring occupies a position, such as that shown in Figure 1, the normal inner cylindrical face of the spring 40 being oifset from the surface of the sleeve 30 but being unsupported thereby and free to operate. The

end portions

38 and 42, however, being deformed inwardly, will contact the surface of the sleeve or reside closely adjacent thereto. The sleeve 36 is provided with a radial projection, abutment member or tracker 44 which is secured to or formed integrally therewith and positioned between the convolutions of the spring, as shown in Figure 1.

In operation the motor shaft 4!] is initially energized under the influence of the starting motor, rotating the sleeve 31] in a clockwise direction, as viewed from the right end in Figure 1, forcing the pinion axially into mesh with the flywheel gear (not shown) on the motor. The tracker having ultimately reached the loop 32, will continue to revolve, driving the spring 26, the sleeve [6 and the pinion resiliently in accordance therewith. When the motor has commenced to operate under its own power it will operate the flywheel gear, which is much larger than the pinion I4, at a peripheral speed greater than that of the pinion, thereby rotating the rotary driving structure l2 in a clockwise direction with respect to the sleeve 30. Thus, the tracker 34 moves in the way 44 to a position shown in Figure 1, retracting the pinion I4. During operation of this device, however, the spring will remain generally centered in a predetermined position with respect to the remainder of the assembly due to the inwardly projecting

portions

38 and 40 which tend to support and space it with respect to the sleeve. This function will take place at all times whether the starter is being employed to initiate operation of the motor or is merely in idle retracted position.

The alternative preferred embodiment shown in Figure 5 comprises a double stranded spring having hooks 22 thereon and a spaced track portion 34, as well as an area 36 where the strands are positioned relatively close to one another. According to this embodiment, however, the spring, instead of being wound in generally helical form to provide a substantially cylindrical appearance, is made originally with an inner configuration whereby the interior edges of the strands are situated along a curve 4G of arcuate form. The interior configuration of the spring is, therefore, generally concave while the exterior is convex, or, taken as a whole, barrelshaped. :When employed in conjunction with a starter organization, such as shown in Figure 1, the terminal portions of the spring, being formed along arcs of substantially the same radii, will reside adjacent the sleeveSll or in contact therewith, as defined heretofore. The intermediate convolutions of the spring 20, however, due to their concave positioning will be spaced from the surface of the sleeve 30 and will operate in the normal manner to resiliently transmit energy to the pinion l4, as well as to guide the tracker 44.

It will be apparent that structures of the instant type normally are supported only at the hook end due to their axial clearance, being free to vibrate and wobble because of the spacing from the sleeve 30 and the lack of any positive connection other than that of the hook ends 22 with the slots 24. Moreover, for convenience in assembly and operation, the hook ends 22 are primarily designed to transmit energy circumferentially thereof and not to form a rigid sole support for the coil 20. As a result the coil tends in most conventional structures to be rather loosely situated. Consequently, this unit is subject to considerable rattling or clashing under the influence of displacing or vibratory forces.

According to the present invention, however, this defect is remedied and the spring relatively positively situated against transverse movement with respect to the sleeve 30. In addition, this effect results in a more unitary assembly since the spring is continually maintained in preferred operative position.

In addition the present structure tends to enhance the wrapping clutch action, that is, at the moment the starting motor begins to transmit a high degree of torque through the assembly to the flywheel gear or the like, the spring tends to contract axially. As a result, the end portions, which are adjacent or already in contact with the central sleeve, tend to further wrap down upon the sleeve and grasp the surface thereof. This wrapping action at the edge causes suificient engagement with the surface of the sleeve to transmit a large portion of the energy from the ends of the spring to the sleeve, consequently BOT distributing the forces at the end. It will be apparent that the present structure improves this known action by causing increasing clutching or wrapping action at and adjacent the points where the extremities of the spring contact the sleeve.

The length of the way 34 is suificient to permit the desired axial movement of the spring and pinion with respect to the sleeve 30 and terminates intermediate of its ends at the predetermined limit of the said track. The axially adjacent convolutions 36 of the spring, as viewed to the right in Figure 1, permit limited tensioning, becoming relatively rigid when the convolutions have been tensioned to a point wherein they closely approach each other. The axially spacedapart convolutions, as viewed to the left in Figure 1, permit resilient action beyond this point. In use, therefore, at the point where the resiliency of the convolutions is lowest, the entire spring, while remaining to some degree resilient, involves a sharply increased factor to ultimately cushion the stresses.

It is thought that the invention and numerous of its attendant advantages will be understood from the foregoing description and it is obvious that numerous changes may be made in the form,

\ construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the form herein described being a preferred embodiment for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

1. An engine starter of the type in which a pinion and a spring coupled therewith move together as a unit, said spring including a double coil of spring wire forming a series of convolutions, a portion of the convolutions at least being spaced to provide a helical way, means traversing said helical way toward one extremity of said coiled spring, providing an abutment surface adapted to be engaged for driving purposes, coupling means provided at the free extremity of each strand at the opposite end of said coiled spring for coupling with said pinion, and a drive shaft unit centrally of the spring, the convolutions being normally spaced therefrom, a portion at least of said convolutions being bent inwardly to contact said drive unit whereby to position said spring with respect to the drive unit.

2. An engine starter of the type in which a pinion and a spring coupled therewith move together as a unit, said spring including a double coil of spring wire forming a series of convolutions, a portion of the convolutions at least being spaced to provide a helical way, means traversing said helical way toward one extremity of said coiled spring, providing an abutment surface adapted to be engaged for driving purposes, coupling means provided at the free extremity of each strand at the opposite end of said coiled spring for coupling with said pinion, and a drive shaft unit centrally of the spring, the convolutions being normally spaced therefrom, portions of the spring being bent inwardly at the extremities to contact said drive shaft unit whereby to position said spring with respect to the drive shaft unit against radial displacement.

3. An engine starter of the type in which a pinion and a spring coupled therewith move together as a unit on a central axially disposed drive shaft unit, said spring including a series of convolutions of spring wire, a portion of the convolutions at least being spaced to provide a helical way, means traversing said helical way toward one extremity of said coiled spring, providing an abutment surface adapted to be engaged for driving purposes, and a coupling means provided at the other extremity of said spring for coupling with said pinion for transmitting energy thereto, a portion of said convolutions of the spring being normally spaced radiallyv outwardly of said drive shaft unit, the extremities of said coil being bent inwardly to a point adjacent said drive shaft unit whereby to position said spring against rattling or lateral displacement.

4. In an engine starter in which a pinion and a spring coupled therewith move together as a unit, a central drive shaft unit, said spring being mounted loosely over said drive shaft unit and coupled adjacent one end thereof to the pinion, the other end of said spring being free from positive attachment, a portion of the convolu tions adjacent said end being offset inwardly whereby to contact said drive shaft unit and support the spring against unauthorized lateral displacement or vibration.

5. In an engine starting device, a cylindrical driven member, a pinion mounted for rotational and axial movement with respect thereto, and a spring operatively connected to said pinion at one end and encircling said cylindrical driven member but spaced radially therefrom, the other end of said spring being free, at least a portion of said spring being offset inwardly toa point adjacent said cylindrical driven member whereby to position said spring laterally.

6. In an engine starting device, a cylindrical driven member, a pinion mounted for rotational and axial movement with respect to said cylindrical driven member, a spring operatively connected to said pinion and encircling said cylindrical driven member but spaced radially therefrom, the convolutions of said spring being spaced to provide a helical track over a portion thereof, and a tracking member secured to said cylindrical driven member and engaged in said track, portions of said spring adjacent the ends being offset inwardly to positions adjacent the cylindrical driven member whereby to position said spring radially and inhibit unauthorized displacement thereof.

7. A coiled spring for forming a driving connection in an engine starter, said spring comprising a double strand of coiled spring wire, the convolutions of said double strand being axially spaced to provide a helical way whereby to accommodate and guide an abutment member, the strands being joined together at one extremity to form a central loop, the opposite ends of said strands having means thereon to transmit energy to a pinion, the extremities of said spring member being offset inwardly and radially.

8. A coiled spring for forming a driving connection in an engine starter, said spring comprising a double strand of coiled spring wire, the convolutions of said double strand being axially spaced to provide a helical way whereby to accommodate and guide an abutment member, the

strands being joined together at one extremity to form a central loop, the opposite ends of said strands having means thereon to transmit energy to a pinion, the coil beingof generally cylindrical configuration and the end portions thereof being deformed inwardly in a relatively sharp curve whereby to position said coil with respect to a central spindle or the like. i

9. A coiled spring for forming a driving connection in an enginestarter, said spring comprising a double strand of coiled spring wire, the convolutions of said double strand being axially spaced to provide a helical way whereby to acoommodate and guide an abutment member, the strands being joined together at one extremity to form a central loop, the opposite ends of said strands having means thereon to transmit energy to a pinion, the coil being of generally barrel-shaped configuration and the end portions thereof being deformed inwardly in a relatively sharp curve whereby to position said coil with respect to a central spindle or the like.

10. In an engine starting device, a drive shaft unit, an engine driving member on said unit for both longitudinal and rotary movement, said member being adapted in one shifted position to operatively engage an engine part to be driven, a coiled spring structure on said unit spaced radially therefrom and connected at one extremity with the engine driving member, said spring structure including a double strand of spring wire forming a helical way, and means rotatable with the unit and positioned between the double strand convolutions of said spring structure for controlling the longitudinal shifting of said spring structure and engine driving member, portions of said spring being offset inwardly to contact said drive shaft unit whereby to support said spring.

11. In an engine starting device, a drive shaft unit, a pinion mounted for rotational and axial movement with respect to said drive shaft unit, and a spring surrounding at least a portion of said unit providing a yieldable driving connection between said drive shaft unit and said pinion, one extremity of said spring having a coupling in the form of an open ended hook, the

- opposite extremity of said spring being free and offset inwardly to a point adjacent said drive shaft unit whereby to position the intermediate portion of said spring laterally with respect to said unit.

JAMES A. CHARTER.