US1879926A - Starter mechanism for internal combustion engines - Google Patents

Description

Sept."27, 1932. A, Dow 1,879,926

STARTER MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed April 13, 1932 2 Sheets-Sheet l INVENTOR.

Alexander Dow q X M4 ATTORNEY.

Sept. 27, 1932.

A. DOW 1,879,926

STARTER MECHANISM FOR INTERNAL COMBUSTION ENGINES Filed April 13, 1932 2 Sheets-Sheet 2 lllllll INVENTOR.

Alexander Dow BY ORNEY.

Patented Sept. 27, 1932 ALEXANDER DOW,'OF NEW YORK, N. Y.,

Assrenon TO nowfrAr-nnrs acume- CORPORATION, A. CORPORATION OF DELAWARE STARTER MEcnAnIsM roe INTERNAL oolvinn's'rion nivomns Application filed. April 13,

This invention relates to starter mechanisms for internal combustion engines intended more particularlyfor the starting or cranking of internal combustion engines,

5 such as are used on motor vehicles, and this invention is specifically directed to that portion of the starter mechanism through which power is transmitted from the starter to the fly wheel of the vehicle.

Under prior practice, there are two well defined forms of engine starter mechanisms. In one form, a toothed pinion operated from the starting motor is adapted to be engaged with and disengaged from a toothed ring 15 mounted on, or teeth formed in, the fly wheel of the engine. A typical illustration of this type of mechanism is shown in patent to Joseph Bijur, No. 1,664,847, issued April 3,

. 1928, Engine starting apparatus. The

other form of engine starter mechanism is gear-less in that the rotation of the fly wheel is accomplished without the necessity of interposed teeth, gears or pinions. This type is exemplified by my issued Patent No.

1,777 ,403, dated October 7, 1930, Power transmission mechanism. In both of these types of starters, a power driving element is engaged with the fly wheel during the starting period and power is transmitted through such engagement to crank the engine.

Experience has shown that the operating connections between the driving member associated with the starting motor and the driven member associated with the fly wheel has been the seat of considerable difliculty,

because in carrying out the starting operation, the engagement between the driven member and the driving member has generally been brought about by acceleration of the starting motor. In the gear type of drive, rapid acceleration of the starting motor moves the pinion into engagement with the teeth on the fly wheel with the result that this pinion, operating at a fairly high speed, is suddenly brought into mesh with stationary teeth on the fly wheel. This causes great shock and wear, and in many cases the force of the impact necessary to overcome the in-' eitia ofthe fly wheel, crank shaft and pistons of the engine is sufii'ciently great tojcause" 1932. Serial No. 605,015.

stripping of the teeth. In thegearless type of starter mechanism, the tendency is to pro-' duce undue wear at particular points on the driven member of the fly wheel and while this isnot serious for an appreciable period, such wear may require adjustment of the parts to compensate for such wear during the long life of a vehicle.

A notable feature of all prior starter mech anisms is thatthe strain or wear on the teeth or the wear on the fly Wheel ring is invariably limited to definite spacedapart portions of these parts. .The reason for this is that, when I an internal combustion engine of four cyl-' inders stops after operation, the fly wheel always comes to "rest at either one of two positions which are directly opposite one another. This is due to the compression within the cylinders. These two opposite positions, are, in reality, not points but areas or zones of about three inches in length. Hence when either of the two types of driving elements described, geared or gear-less, start the fly wheel in rotation, the extreme torque necessary to overcome the inertia of the fly wheel falls upon two surfaces of limited area and this causes excessivewear at these two zones; When the fly wheel is once started, a less torque is needed to keep it in rotation. In asix cylinder engine, there are three positions spaced about the fly wheel at intervals of 120 degrees. The zones of wear similarly increase as the number of cylinders increases.

With the foregoing considerations in mind, the object of the present invention is to provide between the driving member of the starter motor and the fiy wheel, an operative connection which will not only eliminate great strains and consequent breakage incident to the overcoming of the inertia of the parts specified, but which will also distribute the wear equally on all points of the driven mem- I ber, thus obviating the necessity of adjustment at any time.

In practically carrying out thisinvention, 95 I obviate the disadvantages to which I have referred by so associating the starter mocha nism with the fly wheel that when the stationary fly wheel ring is gripped by the start I or mechanism, the operative connections between the starter mechanism and the fly wheel will be susceptible to a yielding or slipping action within limits sufficiently small as not to interfere with proper starting, but suf ficiently great to eliminate shock. In other words, instead of gripping the fly wheel and immediately imparting a rotating force rigidly thereto, the operating connections cushion the transmission of force to the fly wheel and Overcome its inertia without shock.

The advantage of this invention may be conveniently obtained by providing the fly wheel with a starter ring which is adapted to be driven by the starter mechanism during any particular starting operation. This ring instead of being rigid with the fly wheel or formed integral, therewith as are the teeth of prior practice, ismounted on the fly wheel so as to be capable of slight slippage, so that when starting power is transmitted to the ring, the ring will respond to this power immediately and through friction occasioned by resulting slippage will cushionably impart rotation to the flywheel. In the gear type of starter, the ring will be a geared ring, i.'e., will have teeth cut therein, whereas in the gearless type of starter, the ring will have smooth faces adapted to be gripped and driven as will beunderstood.

Features of theinvention, other than those adverted to, will be apparent from the hereinafter detailed description and claims, when read in conjunction with the accompanying drawings.

The accompanying drawings illustrate one practical embodiment of the invention, but the construction therein shown is to be understood as illustrative, only, and not as defining the limits of. the invention.

F igure'l is a face view of an engine fly wheel embodying this invention.

Figure 2 is a side elevation of said wheel.

Figure 3. is a fragmentary side elevation of the fly wheel with a portion'thereof in section and showing the starter mechanism associated therewith.

- F igure4 is a fragmentary section of the fly wheel with the ring removed.

Figure 5 shows. a cross section of. a ring of modified form.

Figures 6 and 7 are perspective views of different elements of thisconstruction.

Referring to the drawings, 1 designates the fly wheel of an engine and 2 indicates any well known conventional form of starting motor. For the purpose of illustration, I have chosen to show in these drawings starting mechanism'of the character described in my prior patent hereinbefore referred to, and having to do more particularly with the gearless type of'starter. In this form the gripping members 3 and 4 are adapted to be op-' erated upon by followers 5 acting against cam ferentially rabbeted to provide an annular seat 8 terminating at its innerend in an abutment 9. The ring 7 is of such size and shape that it may be slipped into the rabbeted portion 8 to seat with a close sliding fit therewith and to bear against the abutment 9. At appropriately spaced distances about the forward face of the fly wheel, the skirt of such fly wheel is radially slotted, as shown at 10, there being six such slots indicated for example in Figure 1 to provide for siX clamp ing members, although, in practice, any appropriatenumber of clamping members may be employed without departing from the in vention. a

The clamping members may be of anysuitable form capable of carrying out the purposes for which they are intended, but for illustration, I have shown these clamping members as comprising bowed clamps 11 preferably made of sheet metal and central ly perforated at 12. The clamps have a length equal to the width of the slots 10, while the width of the clamps is sufficient to permit one lateral edge to bear against the ring 7, while the other lateral edge bears against the base of the corresponding slot 10, as clearly shown in Figure 3. At the base of each slot is a tapped hole 13 and a screw 14 extends through the central hole in each clamp and threads into the tapped hole 13. In order to preclude loosening of the screws due to vibration, which is always found in an engine and associated parts, a locking plate 15 is associated with each clamp. The locking plate has a length equal to the width of'slots 10, and is centrally perforated as at 16 to receive the screw 14. Said plate is further provided with a plurality of locking fingers 17.

In assembling the parts, each screw 14 is first passed through one of the plates 15, and then passed through one of the clamps 11 and thereupon screwed into one of the tapped- In pra'ctice,the parts are assembled in the manner described and the several-screws14 are tightened sufficiently to clamp the ring 7' firmly in position. During this clampingoperation, however, the bowed cross section of the clamps causes these clamps to be placed under some transverse tension which serves in return to clamp the ring 7 fairly tightly between the clamps and the abutment 9 between which parts it is frictionally held in place against relative rotation with respect to the fiy wheel. It will be noted, however, that because of the elastic tension which holds the ring in place, the ring is susceptible when subjected to sudden tangential strains for slight rotary slippage or sliding movement, with respect to the fly wheel. For example, if it is assumed that the motor associated with the fly wheel is to be started from a condition of rest, the first operation in starting is to energize the starting motor 2, and through the acceleration of such motor, the gripping members 3 and 1 which constitute the power driving elements of this construction will be caused to grip the ring 7, for the purpose of driving the same. Bearing in mind that at the time of the gripping operation, the starting motor 2 is rotating at a relatively high velocity, it will be apparent that when the ring 7 is gripped as stated, the natural and desired result is immediate rotation of the fly wheel for cranking purposes.

Experience has shown, however, if a rap idly rotating part is suddenly coupled to a stationary part having considerable inertia the overcoming of the inertia will result either in a shock or in corresponding wear on the ring. lVith the structure of this inven- 1 tion, however, this shock is not appreciable for the reason that the ring is immediately actuated and accelerated and the inertia of the fly wheel and associated parts is overcome gradually by friction due to slippage of which the'ring is susceptible as hereinbefore described. This slippage, however, is not appreciable and in aractice is but a fraction of an inch for each operation. Thus while there is under best conditions slight wear between i the gripping members and the ring, the ring is constantly shifted at each starting operation about theperiphery of the fly wheel and consequently this wear is equalized and made uniform throughout the ring, whereby it is not noticeable at any time even after long periods of use. 7 V

The slippage to which I have referred is graphically illustrated in Figure 1, wherein an arrow 18 on the fly wheel is shown adjacent a mark 19 on the ring. During the next starting operation, slight slippage which results will shift the arrow 18 to the mark 20 on the ring and during successive operations the arrow 20 will be shifted to the marks 21, 22,

' etc, so that the operation of the ring which is the result that the wear will be distributed as stated. The ring shown in Figure 3 is channeled at .23, although said channels may beomitted to produce a ring, of the cross section. shown in Fig. 5. The particular cross section of the ring is not material, so long as it will used to advantage in starting mechanisms of the gear type. In this latter type, the, ring instead of being smooth for engagement with conical gripping members as shown will be a toothed ring adapted to be engaged by a' toothed pinion as will be well understood by those skilled in the 'art., The mode ofoperation will'be' substantially the same that the toothed starting mechanism for the pinion upon engagement with the'toothed slip ring will cause the same to be slightly shifted, so

that at each successive starting operation, the pinion will initially engage with each tooth of the slip ring. Consequently, the wear will be distributed and the slip ring will cushion the starting operation in eithercase. It is notable that since the clamps llare under tension and are more or less resilient, any slight wear which may occur between the ring and the clamps and abutment will be automatically compensated for. V

It will thus be apparent that the invention is susceptible to either type of starter mechanism where a power driving element is adapted to drive a driven element through a slip ring connection as specified.

Having thus fullydescribed the invention, what I claim as new and desire to secure by Letters Patent is:

1. Means for cranking an internal combustion engine embodying a fly wheel associated with the engine to be cranked, a slip ring, means resiliently and frictionally binding the slip ring to the flywheel with such degreeof pressure as to permit slippa e of the ring with respect to the fly wheel w on rotation of the former is started to initiate rotation of the latter and to permit rotation of the fly wheel by the slip ring without appreciable relative slippage after rotation of the fly wheel has been initiated, and a power op erated starter mechanism comprising means to engage with and drive the slip ring.

2. Means for cranking an internal combustion engine embodying a fly wheel associated with the engine to be cranked and provided with an annular cross axial abutment, a slip ring coaxial with the fly wheel and engaging with said abutment, a plurality of resilient clamps engaging with the ring resiliently and frictionally binding the slip ring to the abutment with such degree of pressure as to permit slippage of the ring with respect to the fly wheel when rotation of the former is start ed to initiate rotation of the latter and to. permit rotation of'the fly wheel by the slip ring without appreciable relative slippage" after rotation of the fly wheel has been ini tiated, and a poweroperated starter mechanism comprising-means to engage with and drive the slip ring. V

3. Means for cranking an internal combustion engine embodying a fly wheel provided with a cross axial abutment, a ring seated against said abutment,a plurality of resilient clamps bearing against the fly wheel and also 7 bearing against the ring on the opposite side of the ring from said abutment, screws passing through said clamps and threaded into the fly wheel placing the clamps under sufficient resilient compression to resiliently and frictionally mount the ring on the fly Wheel to permit slippage of the ring with respect to the fly wheel when rotation of the former is started to initiaterotation of the latter and to permit rotation of the fly wheel by the slip ring without appreciable relative slippage after rotation of the fly wheel has been ini tiated, and a power operated starter mecha-' nism comprising means to engage with and drive the slip ring.

4. Means for cranking an internal combustion engine embodying a shaft associated with the engine to be cranked, a driven member arranged coaxially of said shaft, means frictionally securing said member to the shaft with suflicient pressure for limited rela- I tive rotation at the initiation of each cranking operation and for conjoint rotation thereafter, and a starter mechanism embodying means to engage with and drive said member.

In testimony whereof, I have signed the foregoing specification.

ALEXANDER DOW.

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