US1923908A - Engine starter - Google Patents

Description

Aug. 22, 1933. c. P, BROCKWAY 1,923,908

ENGINE STARTER Original Filed Oct. 10, 1921 Z SheetS-Sheet 1 INVENTOR.

ATTORNEY Aug. 22, 1933.

C. P. BROCKWAY ENG I NE STARTER 2 Sheet S-Sheet 2 Original Filed Oct. 10. 1921 56' INVENTOR.

60// P fimcflway ATTORNEY Patented Aug. 22, 1933 rrso s'rA'rs PATENT FFICE ENGINE STARTER Carl P. Brockway, Ridgewood, N. J., assignor to Industrial Research Corporation, Toledo, Ohio, a Corporation of Delaware Original application OctoberlO, 1921, Serial No. 506,662. Divided and this application April 24, 193%). Serial No. 447,111

Claims.

as the internal combustion engine and is a divi- 5 sion of my application for Magnetic and spring yield drive mechanism, Serial Number 506,662, filed on October 10, 1921.

The specific embodiment of the invention herein disclosed takes the form of an electric motor having an extended shaft lying adjacent to the engine fiy-wheel and carrying a drive pinion which is movable axially on the shaft into and out of engagement with the fly-wheel. To take up the meshing shock, a buffer spring is employed,

l5 co-operating in certain movements with the motor armature, which latter member is mounted so as to have a small axial movement in its bearings against the .pull of the field magnetism.

An important object of the invention is to utilize the strong electromagnetic force present in a motor as asource of yield in case the gear teeth engage end to end, with a resultant danger of breakage. It is further'an object to utilize the armature yield in connection with a threaded shaft, carrying a buffer spring or other shock absorbing device, thus eliminating the employment of a sleeve intermediate the shaft and pinion. An object also contemplated is the provision of combined electromagnetic and metallic spring yield in connection with the driving operation,

the two yields balancing each other and obtaining a very uniform and desirable action.

It is further contemplated in connection with the invention, to combine the specific yielding features with the wiring system and units commonly employed so as to organize a new and useful combination of mutually cooperating elements for starting an engine, such as would be applicable, not only to a system employing separate dynamo electric machines for starting and charging, but, also to a single unit system where one machine starts the engine and generates battery current.

The invention, also, is directed toward novel means for maintaining the drive pinion normally out of engagement with the engine gear.

Various additional objects, including such as relate to economies of manufacture and details of construction, will appear as progress is made in the description of the illustrative embodiment herein disclosed, in which Figure I is a sectional elevation of one form of the invention;

Figure II is a sectional elevation of a modified form, including an air cushion;

Figure III is a sectional elevation of still an I other modification;

Figure IV illustrates the wiring circuits and electrical units in connection with the device of Figure I;

Figure V shows a system. applicable toa single unit dynamo electric machine; and

Figure VI is a section taken on lines VI-VI of Figure V.

Referring to Figures I and IV of the drawings, there is shown in section an electric motor 10 having an extended shaft 11, which'shaft carries a pinion 12in proximityto, and adapted to engage with an engine flywheel 13, or other engine gear secured to the crank-shaft 14 of the engine 15.

The motor casing 16 is formed in two parts by the cylindrical members 17 and 18, of equal diameter and with co-engaging and overlapping adjacent edges 19, the outer ends of the cylinders being closed and including .the central bearings 20 and 21, designed to hold the motor shaft 11, through bushings 22. The shaft 11 is slidable to a small degree in its bearings 20 and 21, being limited on the one end by the annular collar 23 and on the other by the larger collar 24, which latter collar serves also as a stop for the shock absorbing spring 25, as will hereinafter be more fully described.

Within the casing the shaft supports the armature 26 with its laminated core 27 positioned adjacent the core 28 of the field 29. The brushes 30 supported by holders 31 fixed to the casing head 17 are narrower in width than the armature commutator 32, so as to permit axial movement of the armature without the possibility of the brushes slipping oif the commutator, either in whole or in part.

Attention is brought to the equivalency in width between the contiguous cores of armature and field and also to the parallelism of the adjacent ends oi" these units, this conformation intensifying the tendency of the armature core to center in a closely defined axial position when subjected to the field magnetic forces.

Beyond the stop ring 2 1, the motor shaft extends to a point near the engine wheel. The shaft towardthe end carries a thread 33 with which the pinion 12 has engagement, and is thereby movable both axially along the shaft and. rotatably thereabout. On the one end the axial movement of the pinion 12 is limited by the spring 25; on the other end the collar 34 stops the pinion.

The pinion 12 is formed to include gear teeth 35, a combined inertia element and stop for engaging the fly-wheel teeth 36, and a tubular member 37, designed with a variable internal diameter which is maximum at the ends and constricted intermediate the ends at a point nearest the inner end. The function of the last mentioned member 37 is to serve as a guide for a movable pin 38, set in the stop 34, and yieldable against a coil spring 39.

A certain degree of force is requisite to move the pinion 12 axially when the pin 38 is at either widened end of the guide tube 37, in as-much as such movement compresses the spring 39, and since the point of the tube of maximum constriction is nearest the inner end thereof as shown in Figure I, the inclination 'of the inner tube wall from the inner end to the constructed point is more abrupt than that from the outer end to this point, and more resistance is offered, therefore, to inner movement of the pinion to meshing position than movement from meshing position to the point of disengagement. Thus the pinion 12 is normally maintained in its disengaged position, unless the shaft 11 is subjected to an appreciable rotativeforce.

Referring now to Figure IV, there is a diagrammatical showing of the series field winding 29 connected by appropriate circuits lo and 41 to the storage battery 42, a starting switch 43 intervening. In parallel with the motor, there is connected to the battery a lightin circuit 44; including lamps 45 and a switch 45, and a gencrating circuit 46, including an engine operated generator 47 and automatic switch 48. An ignition circuit 49 is also connected across the motor including the switch 50, primary coil 51, interrupter contacts 52, condenser 53, secondary coil 54, and distributor 55. The details of the ignition are conventional and will not be described.

' Proceeding now to the operation of the system and gears, it is obvious that a self-sustaining automatically operated electrical arrangement has been described, wherein current from the storage battery 42 supplies energy to the motor which starts the engine, the ignition maintains the engine in operation, the engine operates the generator, which in turn charges the battery. Energization of the motor field subsequent to closure of the switch 43, results in rotation of the shaft 11 and an inward movement of the pinion 12 due to its threaded engagement with the shaft combined with its relative inertia. The force of movement of the pinion is such as to overcome the restraining action of the pin 38 and it travels axially into mesh with th engine flywheel 13.

As is apparent from Figure I, the final limit of movement'of the pinion 12 is determined by the extended portion 36, but prior to such limiting engagement the spring 25 contacts with the pinion with progressively increasing force restrains movement of the same until the engine load is yieldingly counter balanced, though at this point the rotation of the engine flywheel will already have been initiated. In this manner a non-rigid, yielding drive is obtained, without utilizing a spring directly in the line of power transmission and the variation of load from external causes or through the engine pistons going over the compression points as well as the shock due to gear engagement at starting are all properly and efliciently taken care of.

In the event that the pinion and teeth fail to mesh correctly, the continued rotation or" the shaft screws out the armature against the field magnetism until the pressure on the pinion is lization of air as a shock absorber.

suilicient to impart a small rotation when enmeshment occurs, the field returning the shaft to normal position.

The modified structure of Figure II differs over Figure I in the different means employed in holding the pinion in disengagement and in the uti- The pinion includes a toothed portion 61 which is fiat on its outer end and adapted to contact with the shaft end stop 62. The inner face of the pinion merges in a tubular member 63, which encloses the shaft and is displaced therefrom to include a spring element 6 as described below. The inner terminal of the tubular member has sliding contact with the inner surface of another tube 65, the latter being formed integral with the casing element 16. Thus it is apparent that the entire shaft extension 66 is enclosed, when the pinion is in disengaged position, by tubes 65, and the pinion 60, there being formed on the interior or" the tubes an air chamber 67. One end of this chamber'is closed by a ring 68, fixed to the shaft and movable axially within the tube 65; the other end is closed by the pinion 60 although leakage of air to a limited extent between the threaded shaft 66 and the pinion, and also between the pinion tube 63 and the tube 65, is always possible.

The coil spring 64, of fairly light and flexible construction, contacts against the ring 68and inner wall of the'pinion proper 61, thus normally maintaining the pinion at disengaged position, although yielding when a pronounced force is applied to the motor shaft.

In operation, the rotation oi the shaft 66 screws in the pinion against the spring (i l and also the air expansive force. This latter force is, at'lirst, not pronounced due to leakage, but rapidly be- 7 comes so, subsequent to gear enmeshment, largely the air cushion; moreover, such movements in thegear mechanism will be hindered through the suction action of the pinion. sleeve63.

The modification of Figure III has the end of the casing 16 drawn out into a tube carrying at the outer end the bearing 71 and bushing 72 for the *notor shaft 73, Beyond the bearing 71 the shaft is threaded to receive the pinion 74, which latter is normally maintained at the outer limit of its movement by the relatively weak. coiled spring 75, seated respectively against the bearing '71 and against the opposing wall of a pocket 76 in the pinion. A stop 77 adapted to seat in a pocket 78 formed in the outer wall of the inertia ring 9 of the pinion 74, limits outer movement of the pinion, while the inner face 80 of the inertia ring 79 contacting against the teeth 36 of the flywheel 13 limits inner movement of the pinion.

The armature of the motor, as in the other modifications is subject to a lateral. or axial.

the bushing 72, and yieldingly tends to oppose such axial movement.

The operation of this device is characterize by the combined yieldable action of spring 81 and magnetic field during the entire starting operation, whereas in the other devices, the field force is effective only when the gears fail to mesh. When the face contacts with the flywheel, the armature is drawn out slightly against the field and spring until equilibrium of forces is obtained, whereupon a flexible and yielding drive is set in action between the motor and engine to start the same. This arrangement has very marked efficiency in utilizing all available yielding forces in the motor, permitting the use of a smaller size spring 81 and overall protection therefor.

In Figure V there is illustrated a drive mechanism embodying the essential features of the invention and incorporated in a system of the single unit type, that is, where a single dynamo electric machine charges the storage battery and starts the engine. The details of the drive correspond essentially to those of Figure I. There is an extended shaft which is threaded to receive a drive pinion 91, which latter element is limited in its axial movement on the inner end by the coil spring 92, and on the outer end by the end stop 93. Means for holding the pinion in normal disengagement are as detailed in my copending application, Serial Number 478,228, and include an inertia ring 94 pivoted to the pinion, and bearing at its point of greatest distance from the pivot, a spring hook 96, adapted to hook over the end stop 93, when the rotation of the ring 94 is sufficient to tip it to a position normal to the shaft. 1 There is also a camming member 9! at the extreme end of the hook 96 which permits the hook 96 to cam itself over the stop 93 to a position of engagement therewith.

The dynamo electric machine illustrated is in this instance disclosed as a two winding, two commutator machine, although the invention may readily be applied to a machine with a single winding and commutator. One Winding is utilized for the motorizing function and the other for the generating function, the motor winding as illustrated including the commutator 98, the battery 42, switch 43 and the series field coil 99, and the generating winding includingthe battery 42, automatic switch 48 and the parallel connecting field coil 100.

The generator end of the armature shaft, beyond the commutator, is squared, and has a sliding engagement with a similarly formed extension 101 of a stub shaft 102 so that rotation only, is transmitted between the two members. From the stub shaft 102, connection to the engine crank shaft 14 is secured through the crank shaft gear 103, chain drive 104, gear'105, auxiliary shaft 106 and conventional friction ball clutch 107.

Operation of mechanism and system of Figure V is as follows. With the engine dead, energiza tion of the dynamo by closure of switch 43 causes operation of the same as a motor. Consequent rotation of the motor shaft screws in the pinion 91 from the position as shown in engagement with the flywheel and in compression of spring 92, whereupon the engine is started.

I When the engine becomes self operating, the pinion is screwed outwardly with accelerated speed sufficient to rectify the inertia wheel to normal, and the spring hook 96 thereupon rides over the stop 93 and, with the continued operation of the motor shaft, is maintained at this point. When the engine, andthe connected motor shaft, slows down, the weight wheel 94 is tipped bya spring (not shown), and the pinion released for a subsequent meshing operation.

When the engine starts up, the voltage of the machine generated by the generating windings reaches a point'at which the automatic switch 48 is operated to closure, whereupon current flows to the battery to charge the same. During the starting operation the friction clutch 107 runs free due to the relative speed of motor shaft and auxiliary shaft 106. 'The starting of the engine, however, makes the clutch active, and. a drive connection from the engine crank shaft to the dynamo is established.

Should the starting gears fail to mesh properly the armature is pulled out slightly as in the previously described modifications, the shaft sliding in the stub extension 101.

Various other modifications of the apparatus and systems described are obvious, but the specific details disclosed are illustrated rather than definitive, the invention being limited only by this scope of the appended claims.

What I claim is:'

1. In a gear mechanism, the combination of a gear; a shaft yieldably mounted adjacent the gear; a pinion slidably mounted on the shaft and movable into and out of engagement with the gear; a radially movable member secured to the end of the shaft; a spring for holding said member at the outer limit of its movement, said pinion having a cylindrical recess at its outer end and said resilient member adapted to yieldably engage the surface of said recess when the pinion is at the outer limit of its movement and disengaged from the gear.

2. In a gear mechanism, the combination of a gear; a shaft adjacent the gear; a pinion having screw-threaded engagement with the shaft, said pinion having a recess at its outer end formed circumferentially about said shaft; a tubular extension to said recess fixed to the pinion on its outer face; a member attached to the shaft and adapted to engage the surface of said recess and tubular extension; resilient means tending to hold said member in engagement with the wall of the recess and extension; and means for rotating said shaft.

3. In a gear mechanism, the combination of a gear; a shaft adjacent the gear; a pinionhaving screw-threaded engagement with the shaft, said pinion having a recess at its outer end formed circumferentially about said shaft; a tubular extension to said recess fixed to the pinion on its outer face; a spring held member attached to the shaft and adapted to engage the surface of said recess and tubular extension; resilient means tending to hold said member in engagement with the wall of the recess and extension; and means for rotating said shaft, the inclination of the wall of the recess along its axis in relation to the axis of the shaft being different from the corresponding angle of inclination of the recess extension with reference to the shaft axis.

4. In a gear mechanism, the combination of a shaft; a pinion having a tubular extension provided with a recess and having screw-threaded engagement with said shaft and movable axially thereupon; and means secured to said shaft and in slidable engagement with the recess in said pinion for yieldably maintaining said pinion at the outer limit of its movement, said means being effective throughout an extended length of movement of the pinion on the shaft.

5. In a gear mechanism, the combination of a gear; a shaft adjacent said gear; a pinion having a tubular projection and a recess adjacent thereto, said pinion being movable into and out of en- 5 gagement with said gear and mounted upon said shaft; and means carried by said shaft for yield-

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