US2316122A - Engine starting mechanism - Google Patents

Description

Ap 6, 1943. R. M. NARDONE ENGINE STARTING MECHANISM Filed Nov. 14, v1941 2 Sheets-Sheet l I N VEN TOR! April 6, 1943- R. M. NARDONE ENGINE STARTING MECHANISM 2 Sheets-Sheet 2 Filed Nov. 14, 1941 IN VEN TOR. M/VmwA/f:

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ffii/Ex Patented Apr. 6, 1943 2,316,122 ENGINE STARTING MECHANISM Romeo M. Nardone, Westwood, N. J., assignor to Bendix Aviation Corporation, South Bend, Ind.,

a corporation of Delaware Application November 14, 1941, Serial No. 419,203

(Cl. 12312'9)l 6 Claims.

This invention relates to engine starting mechanism and more particularly to a starting mechanism of the inertia type, in which there is a period of energy storage in an inertia element (flywheel, for example) prior to movement of the engine-engaging, or cranking element, to cranking engagement with the member of the engine to which initial rotary movement is to be imparted.

vObjects of the present invention are to make advantageous use of all the energy of the flywheel all the way down to zero iiywheel speed; and to minimize the shock of engagement. The latter I propose to bring about by engaging the starter and engine jaws at zero rotary speed, thereafter increasing the rotative speed of the starter jaw. In this connection a feature of the invention, as claimed herein, is the provision of means wherebyalthough the engine-engaging jaw is at all times mechanically connected to the flywheel of the startersaid jaw nevertheless remains stationary while the flywheel is being accelerated to its normal speed, which (in the tests thus far made) is 32,000 R. P. M. Hence when engagement occurs the jaw is at zero speed.

Another object is to crank the engine at speeds over and above that which would normally obtain with a fixed gear ratio between iiywheel and engine-engaging jaw, the cranking speed being characterized by a tendency to increase during at least the initial stage of the run-down period of the flywheel, rather than to decelerate therewith, as has been the tendency heretofore.

A further object is to make possible directcranking, when desired, independently of any flywheel rotation.

Still another object is to produce a direct cranking action by use of energy from a prime mover additional to the flywheel, said prime mover being operative, rst to accelerate the ilywheel, and subsequently-upon reversal in its direction of rotation-being instrumental in establishing connection between the starter and engine, and also in helping the flywheel to speed up the engine and continue to transfer energy thereto even after the flywheel has come to a complete stop, and so long as is necessary to insure effective starting.

Starting devices embodying the principles above described, and adapted to achieve the foregoing objectives, are illustrated in my copending applications No. 296,681, led September 26, 1939, and1 No. 397,794, filed June 12, 1941, in which applications certain features of the invention are claimed. Other-that is, divisible-features comi torque transmitting that the planetary spider mon to the two disclosures, as well as the specic features which distinguish the present disclosure from the disclosure of the copending cases just referred to, are claimed herein.

In the drawings:

Figs. 1 and 2 together constitute illustration of the preferred form of the invention;

Fig. 3 is a transverse view along line 3 3 of Fig. 1;

Fig. 4 is a transverse View along line 4-4 of Fig. 1; and

Figs. 5 and 6 together illustrate a modification.

In my applications No. 293,681 and No. 397,794, filed September 26, 1939, and June 12, 1941, respectively, I have shown a starting mechanism embodying the concepts above described, and including an electric motor, flywheel, gear tra-in and engine engaging element, all integrated into a single self-contained unit adapted to be attached directly to the engine crankcase. Such a single self-contained unit is preferable, but in some installations there is insufiicient room to permit the mounting of a complete starter (comprising the electric motor, flywheel, gear train, clutch, etc.) directly to the engine crank case. In such installations, it is desirable to separate the motor from the gear box, mounting the gear assembly directly on the engine and the electric motor at some more convenient position, somewhat removed from the gear box.

Figs. 1 and 2 show an arrangement wherein the gear assembly (including a suitable reduction gear train, clutch, screw-shaft and jaw) is connected to the actuating motor by means of a flexible shaft I I rotatable in a ilexi- Motor I3 is similar to the motor No. 397,794, above referred to, and includes a 4 to l step-up gear train to drive flywheel I6. Flywheel I 4 is first brought up to speed by energizing the motor I3 in one direction of rotation, during which period ilexible shaft II remains stationary due to the fact or cage (shown at 31 in Figs. 1 and 4), is locked by means of the overrunning clutch` elements II and liI, which prevent its rotation. When the motor I3 is reversed, shaft II begins to revolve and the flywheel energy is discharged through the shaft into the gear train 2l, 22 (Fig. 2). The speed of the shaft II will, of course, depend upon the speed of the flywheel I4, reduced by the gear ratio between the said iiywheel and shaft, plus the speed of the motor, which latter depends upon the torque at the point of engagement with the engine, namely, at the element 8| (Fig. 2). The element 8l beble casing I2. 2I of my application gins to move forward into engine engaging position as soon as shaft II starts rotating. When the engine starts, the member 8| is automatically demeshed, and the motor may be dre-energized.

Fig. 1 also shows the addition of a hand crank attachment at the rear end of the motor I3. The purpose of this attachment is to permit operation of the starter in case of motor failure, or where it is desired to conserve battery current. This consists of a step-up gear train 30 of the compound planetary type, having a step-up ratio of approximately 84 to l between hand cranking shaft 28 and motor armature shaft 26, so as to permit the rotation of the armature shaft 26 at a speed of 7500 R. P. M. with a hand crank speed of 90 R. P. M. The high-speed shaft 25 of the gear train is drivably connected to the square end portion of armature shaft 26; the shaft 25 being square-socketed at its end. Brake drum 35 keyed to shaft 25 has a brake band 48 (Fig. 3) wrapped around its outside diameter but normally free of the drum. This brake band is hinged at point 45, which is a stationary support, while the opposite end of the band is connected to arm 58 on stud 55. Rotation of arm 58 from the full to the dash line position tightens the band around the drum and stops the latter from rotating. Arm I) is moved by means of the lever 80 (Fig. l), manually operated when desired.

For manual operation, the effort is applied at hand cranking shaft 29 which rotates armature shaft 26 at a stepped-up speed. This in turn energizes flywheel I4 (through the 4 to l ratio between armature and flywheel) to a speed of approximately 30,000 R. P. M. When it is desired to discharge flywheel energy to start the engine, lever B8 is manually shifted to tighten the brake band on the drum 35. This stops the armature of the motor I3, whereupon said armature then becomes a reactance point for the gear train. Flexible shaft II then begins to rotate, and member 8I moves axially to the engine engaging position.

When the engine starts, member 8l is demeshed and brake arm 59 may be released.

Another arrangement to permit hand cranking is shown in Figs. 5 and 6. This involves a rightangle drive (.18, 80) also a brake drum and brake band (corresponding to the elements 35 and 40 of Fig. 3), and a flexible shaft 10 leading from the step-up gear train (Fig. 6). The motor I3 is accelerated to its proper speed by manual effort at the hand cranking shaft 85 through the step-up gear train 15-10--19-8, to accelerate the flywheel, as in the embodiment of Figs. 1-4. Likewise (as in Figs. 1-4) to discharge flywheel energy, the brake band is tightened on the drum by pulling on the lever l0!) (Fig. 5)

Gear train 15 is constructed like that of Lansing Patent No. 1,979,162, as is also gear train 30 (Fig. l).

The energizing electric circuits for motor I3 are preferably the same as those shown in Fig. 2 of my cc-pending application No. 397,794, above referred to, and reversal of direction of motor rotation is brought about by selective energization of the commutator brush-engaging solenoidsnot shown herein, but corresponding to solenoids II2 and IIS of my said co-pending application. An important advantage of this method of rotation control is that it normally leaves the motor armature free of any frictional drag, as both sets of commutator brushes remain raised out of engagement with the commutator, so long as no current is flowing. Hence, in the event of manual operation, the armature is readily rotated independently of any brush restraint, the brushes being out of contact therewith.

It is to be understood that elements 26, 32, and 33 (Fig. l) are integrated with each other in any suitable manner, as are the corresponding elements 26, 32, and 33 of my co-pending application, just referred to.

Likewise, as in my co-pending application, annulus gear 33 meshes with a planetary idler pinion 34 rotatably carried on a frame, or spider," 36-31, whose hub is shown as keyed to a centrally disposed shaft 38 which is rotatable relatively to the shaft 2li-32, and terminates in a threaded socket which receives the correspondingly threaded end of a coupling element 55, to which coupling element 55 the flexible shaft I I is drivabiy secured, as shown. Surrounding shaft 38 is a sleeve 46 that is shown as keyed to the hub of flywheel I4; said sleeve 46 having teeth 41 which constitute the sun gear of the planetary system, of which planetary system the gear elements 33 and 34 are co-operating parts. These gear elements 33, 34, and 41 are identical in structure and mode of operation to the similarly designated elements 33, 34 and 41 of my co-pending application, No. 397,794, above referred to.

The hereinabove described stationary element 4I constitutes, in effect, the inner race of an overrunning clutch, not only in respect to the rollers I1 which engage spider 31 (see Fig. 4) but also in respect to the rollers I8 which engage an outer race 58 constituting an integral part of flywheel I4. Rollers I1 function in the same manner as pawls '52 of my co-pending application No. 397,794, and rollers I8 function in the same manner as pawls 51 of my said co-pending application. To achieve such functioning, the cage 31 and the flywheel member 58 are provided with conventional means-corresponding in their action to the bent springs 23 of Patent No. 1,997,370 granted to H. J. Le Vesconte on April 9, 1935-to cause the rollers I1 and I8, respectively, to grip the respective adjacent flat sides of the stationary member 4I (see Fig. 4) when urged in one rotational direction, while permitting free rolling action when the rollers are urged in the opposite rotational direction. Thus rotation of cage 31 will be possible in one direction only, and the same will be true of flywheel I4. Hence the operation is as follows: During flywheel acceleration, planetary spider 36-31 is held stationary (by rollers I'.' and inner race 4I) and therefore the elements driven therefrom-and this includes parts 38, 55, II, 2l, 23, 61, 83, 88, and 3Ido not rotate; but after proper flywheel speed is achieved, the reactance action-produced by (a) reversal of motor rotation (when the electrical source of energy is employed), or (b) application of brake 40 (when hand energization is employed)-causes spider 36-31 to rotate (the rollers I1 over-running) and spider 31 in turn causes shaft 38 and all parts driven thereby to rotate, which rotation includes the starter barrel 61 and clutch 83. This rotation of starter barrel 61 and clutch 83 results in immediate screw action upon screw-shaft 88, whereupon engine-engaging jaw 8l moves forward into engine-engaging position. Engagementis therefore at zero speed and zero torque; hence there is no concurrent slippage at clutch 83.

As the resultant transfer of energy to the engine causes flywheel I4 to decelerate to zero speed, rollers I8 take effect and prevent rotation of the flywheel in the reverse direction, even though elements 26, 32, 33, 34, 36-31, 38, H, 2l, 23, 88, and 8| continue to rotate, under the urge of the continued energization of motor I3, (assuming the electrical method of operation to be employed). Of course, when the manual method of operation is employed, there is no contin-ued rotation after dissipation of all energy previously stored in the flywheel, hence no tendency of the flywheel to reverse rotation after deceleration to zero speed.

What is claimed is:

1. In an engine starter, the combination of a rotatable inertia member, means for driving the inertia member including a driving gear, a driven gear and an intermediate gear, said intermediate gear being rotatably mounted in a rotatable frame, means including a flexible torque-transmitting shaft for connecting said rotatable frame to the engine in a manner to crank the same, means for preventing' rotation of the frame in one direction, and means acting upon said driving gear for reducing the speed of the driving gear whereby the reaction force on the frame is reversed and the frame is rotated in a direction to crank the engine.

2. In an engine starter, the combination of a rotatable inertia member, means for driving the inertia member including a driving gear, a driven gear and an intermediate gear, said intermediate gear being rotatably mounted in a rotatable frame, means including a flexible torque-transmitting shaft for connecting said rotatable frame to the engine in a manner to crank the same, means for preventing rotation of the frame in one direction, and means acting upon said driving gear for rst decelerating and thereafter reversing the direction of rotation of the driving gear whereby the reaction force on the frame is reversed and the frame is rotated in a direction to crank the engine.

3. In an engine starter, the combination of a rotatable inertia member, means for driving the inertia member including a driving gear, a driven gear and an intermediate gear, said intermediate gear being rotatably mounted in a rotatable frame, means including a flexible torque-transmitting shaft for connecting said rotatable frame I to the engine 1n a manner to crank the same, means for preventing rotation of the frame in one direction, means acting upon said driving gear for first decelerating and thereafter reversing the direction of rotation of the driving gear whereby the reaction force on the frame is reversed and the frame ls rotated in a direction to crank the engine, said last-named means also tending to concurrently decelerate the inertia member and thereafter tending to reverse the direction of rotation thereof, and means distinct from, and acting separately from, said lastnamed means to prevent such reverse rotation of the inertia member.

4. In an engine starter, the combination of an inertia member, means for rotating the inertia member including a gear train having one element thereof drivably connected to said inertia member, a rotatable frame supporting a second element of said gear train, means including a flexible torque-transmitting shaft for connecting said rotatable frame to the engine to be started for transmission of initial rotary movement to the latter, and means4 for holding said frame stationary during the rotation of the inertia member for storage of energy therein.

5. In an inertia starter, an engine engaging element, a rotatable inertia element, manual means for accelerating said inertia element independently of said engine engaging element, means for retarding rotation of said manual means and means responsive to operation of said retarding means for causing transmission of torque from said inertia element to said engine engaging element, said last-named means including screw-action means for moving said engine-engaging element to engine-engaging position, said screw-action means further operating to de-mesh said engine-engaging element when the engine starts.

6. In an inertia starter, an engine engaging element, a rotatable inertia element, manual means for accelerating said inertia element independently of said engine engaging element, means for retarding rotation of said manual means and means responsive to operation of said retarding means for causing transmission of torque from said inertia element to said engine engaging element, said retarding means including a brake and manual means for applying said brake, and said torque transmitting means including screw-action means for moving said engine-engaging element to engine-engaging position, said screw-action means further operating to de-mesh said engine-engaging element when the engine starts.

ROMEO M. NARDONE.

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