US1197744A - Gearing. - Google Patents

Description

W. O. KENNINGTON.

GEARING.

,APPLLCATIQN FILED FEB. 6, 1915.-

1,197,744. Patented Sept. 12, 1916.

UNITED STATES PATENT OFFICE.

wI'LLrAM o. KENN'INGTON, or ANDERSON, INDIANA, ASSIGNOR, BY MESNE ASSIGN- MEN TS, T0 ECLIPSE MACHINE COMPANY, OF

or 1\TEW YORK.

ELMIRA, NEW YORK, A CORPORATION GEARING.

Specification of Letters Patent. Patented Sept. 12, 1916.

Application filed February 6, 1915. Serial N 0. 6,559.

To all whom it may concern Be it known that I, W'ILLIAM O. IQEN:

NINGTON, a subject of the King of England, and a resident-of Anderson, in the county of Madison and State of Indiana, have invented a new and useful Improvement in Gearing, of which the following is a specification.

My invention relates to gearing wherein a gear is caused to slide into or out of mesh with another gear by traveling along a screw threaded or similar shaft.

The particular purpose of my invention is to prevent the gear on the threaded shaft from rebounding into engagement with the other gear after it has been thrown out of mesh therewith, and a further purpose is to reduce the blows on the ends of the teeth at the time of meshing. I thus reduce the wear and destruction of the teeth. 1

I have made the invention with reference to the gearing connecting electric starting motors to internal combustion engines but attached parts, shown partly in section, and

turned in the opposite direction to Fig. 1. Fig. 3 is a view of the right hand end of Fig. 2, but with the shaft also shown. Fig. 4 is a section of the pinion alone along the line 44: of Fig. 2. Figs.'5 and 6 show modified forms of my invention, being sections through the weight, normal to the axis of the shaft 20, (corresponding to a section along theline 55 of Fig. 2 looking toward the left).

Referring to' Fig. 1, there is an internal combustion engine, having cylinders 1, crank case 2, crankshaft 3 and flywheel 4, similar to those ordinarily used. The flywheel. 4: has teeth on its periphery, so that it can act as a gear. There is a bracket 6, integral with the crankcase 2, to which is secured the electric starting motor 7. There isa storage battery 8 and starting switch 9, said motor, battery and switch being connected in series by the wires 10, 11 and 12.

- This extension is screw'threaded, with one,

two or more threads, as may be desired. There is a small gear, or pinion 21 on the shaft 20, and this (see Fig. 2) is internally threaded, so that rotation of the pinion relative to its shaft causes the pinion to travel longitudinally along the shaft. Referring again to Fig. 1, the relations of the shafts 3 and 20 are such that when the pinion 21 has moved to the right its teeth mesh with those with the flywheel. The teeth of both gears are preferably chamfered on the ends which engage each' other when meshing starts. There is, preferably, a spiral compression spring 22, having its right hand end secured to the shaft 20, but its left hand end free to stop the'motion of the pinion. lVhen the pinion 21 abuts this spring, saidpinion is in mesh with the gear 1. There is a pin 24 projecting radially from the left end of the shaft 20, against which can abut a shoulder, hereinafter described, of the pinion 21, and when this occurs, the pinion is far enough to the left for its teethto be entirely free of those of the gear 4.

There is a weight retainer 25, shownin detail in Figs. 2 and 3, on one end of the pinion. This is rigidly secured to the pin ion, in the form shown this being done by a very tight fit between the weight retainer and the pinion. Surrounding said weight retainer is an annular weight 30. The

weight may rotate on the weight retainer, but there must be a certain amount of friction between these parts as will appear later. There is an annular groove 31 in said weight, adapted to be filled with grease or other suitable material which will cause this free of those of the gear 4.

The mechanism is preferably, though not necessarily, arranged so that the pinion 1s in engagement when at the inner end of ts motion, that is, when it is in the position nearest the motor, as shown herein. This construction is advantageous in that the leverage 'efi'ect tending to bend'the shaftor otherwise strain the mechanism during the use thereof is less than if the pinion were operative when at the outer end of its longitudinal motion. V

The above describedform of the invention operates as follows: Referring to Fig. 1, when the starting device is not in use, the position of the pinion '21 is far to the left, so that the teeth of said pinion and the flywheel 4 are entirely free of each other, this being the normal or inoperative position. To start the engine, the switch 9 is closed, whereby the storage battery 8 starts the electric motor 7, and the shaft 20 is thus rotated. "The pinion 21, however, turns but slowly, instead of acquiring the speed of the shaft. This is due to the inertia of the pinion 21, and that of the weight 30. If the friction between the pinion and the weight is great enough to cause the weight to rotate with the pinion, this weight merely adds its inertia to that of the pinion, but if the pinion turns faster than this weight, the frictional resistance between the weight and the pinion still tends to retard the rotation "of the pinion. Thus, at this period in the operation of the apparatus, the weight helps to make the rotation of the pinion slow compared with that of the shaft whether or not there is any relative motion between the pinion and the weight. w

Since the pinion is rotating slower than the shaft-20, the screw and nut relation between this shaft moves the pinion to the right, and its teeth are brought into mesh with those of the gear 4:. After the pinion has moved far enough to the right to bring it fully in mesh with the gear .4, the longitudinal motion of the pinion is stopped by theabutment of the pinion 21 against the spring 22. After this occurs, the pinion 21 1s obliged to rotate at least as fast as the shaft 20. The motion of this shaft, acting than the shaft,'and,

through the pinion 21, now causes the flywheel 4: to rotate and the engine is started. By employing the spring 22 instead of a rigid stop, the longitudinal motion of the pinion is stopped gradually, and the engine is started withless shock than if the longipinion were arrested This makes the pinion travel to the left, whereby its teeth are umneshed from thoseof the flywheel.. The motion of the pinion to the left is stopped by the, abutment of the shoulder 32 against the pin 24 and the principaladvantage of this invention is in the manner in which thisstop is made. In

ordinary forms of arrangement, wherein the pinion is not provided with a weight movable relatively thereto, it often occurs that the pinion, after striking the pin, rebounds therefrom and travels far enough toward the flywheel, resulting in injury to the ends of the teeth, and my invention prevents this as follows: WVhen the engine is started, the speed of the pinion 21 is suddenly increased,

-and the inertia of the Weight together with the possibility of relative motion between the weight and the pinion may prevent this weight from acquiring as rapid rotation as that acquired at this time by the pinion. As soon as the teeth of the pinion are free from those of the flywheel, so that the speed of the pinion is no longer determined by the speed of'the flywheel, the frictional drag between the weight and the. pinion lowers the speed of rotation of the pinion. The excess of the pinion speed above the shaft speed is thereby reduced, so that when the shoulder on the .pinion abuts the pin 24, it is moving slowly ,relatvely to this pin and does not rebound;

Even if the weight should acquire the v speed of the pinion when the pinion is aocelerated by the engine, this weight is still useful in preventing rebound of the pinion, for when the shoulder -on the pinion abuts the pin 24, the moment of inertia of the I weight causes it to continue turning faster should the pinion rebound, the friction between the weight and the pinion would cause the weight to drag the pinion back against the pin .24, instead of permitting the motionof rebound to continue so far that the teeth of the pinion clash w1th those of the flywheel. Of course, after the engine is started, the motor is stopped, as usual, by opening the switch 9.

A method which has heretofore been used to-prevent the rebound of the pinion from causing clashing of the teeth has been to so arrange the parts that when the pinion has reached the left hand limit of its motion there is a considerable longitudinal distance between the teeth of the pinion and those of the flywheel, so that the rebound of the pinion will not be sufficient to cause clashing of the teeth. Compared with my invention, this possesses two disadvantages: First, it requires a longer shaft to provide for this increased clearance. This is particularly objectionable in automobiles, where the parts are crowded. Second: The pinion will frequently stop with less rebound than the maximum rebound that must be provided for in the clearance and therefore the pinion will have to travel farther before going into engagement than with my invention. Now, the farther the pinionhastotravel longitudinally, the faster the rotation it will acquire before engagement of the teeth. This rotation should be kept to as low an amount as possible, because it tends to rub together and injure the ends of the teeth at the instant that they are just engaging.

In Fig. 5 the friction between the pinion or rather the weight retainer and the weight 30 is augmented by a fiat spring 140, secured by screws 141 to the weight retainer,

here.designated 131, said Weight retainer.

being suitably recessed to accommodate this spring. The tendency of" the spring 149 to straighten itself increases the friction existing between the weight 30, and the weight retainer 131.

Fig. 6 shows a form of the invention wherein the weight, here designated 230, and not provided with an annular groove can rotate faster than the pinion 21, but not slower. The weight and the weight retainer are mechanically connected by what may be termed a ratchet like connection, since it permits the same character of relative motion as. does a ratchet. There is a recess in the inner periphery of the weight, in which is a cylindrical roller 240. There is a plunger 241, fitting in a hole in the weight 230 and forced against the roller 240 by a spiral spring 242. The shape of the notch in the weight 230 is such that when the weight is rotated, relatively to the pinion 21, in the direction indicated by the arrow, the roller does not cause binding be"- tween the weight and the weight retainer 31, but when an attempt is made to turn the weight in the opposite direction, the roller moves toward the narrow portion of the notch and grips the weight retainer 31, so as to prevent rotation. This mechanism is well known and understood, and is here shown as an example of the various forms of ratchet like connection that may be employed. In this form of my invention, the weight cannot rotate slower than the pinion, although it may rotate faster, due to the the weight assisted in limiting rotation, and

therefore produced quick meshing, even though there was no motion of the weight relative to the pinion, and it was also shown that even if the weight should acquire the speed of the pinion, when the pinion is accelerated by the operation of the engine under its own power, that the weight would continue to rotate after the shoulder on the pinion abuts the pin 24, andthat this continuance of rotation would assist in preventing or limiting the rebound of the pinion from the pin. This is What occurs in the last mentioned form of the invention.

In the foregoing I have described the i more important use of my invention, but I do not limit it to the specific application shown, since it may be applied to many other types of mechanism besides starting motors for internal combustion engines. Neither do I limit my invention to the specific constructions shown, since, it may be constructed in a variety of ways without departing from the spirit of the invention. For example, the motion wherein translation occurs simultaneously with rotation and which I term a substantially helical motion, may be produced by other means than the cooperating internal and external screw threads shown. Furth rmore, I do not limit myself to gears having their shafts or axes parallel.

I claim as my invention:

1. In a starter for engines, the combination-with a threaded shaft, a threaded pinion thereon, and a gear to be started by the pinion, of a weight carried by the pinion and rotatablerelatively thereto.

2. In a starter for engines, the combina tion with a threaded shaft, a threaded pinion thereon, .and a gear to be started by the pinion, of an annular weight carried by the pinion and rotatable relatively thereto.

3. In a starter for engines, the combination with a threaded shaft, a threaded pinion thereon, and a gear to be started by the pinion, of an annular weight carried by the pinion and rotatable relatively thereto, and

friction means between said weight and pinion.

4. In .a starter for engines, the combination with a threaded shaft, a threaded pinion thereon, and a gear to be started by the pinion, of an annular weight rotatable on said pinion, and a spring friction device arranged between said weight and pinion.

5. In a starter for engines, the combination with a threaded shaft, a threaded pinion thereon, and a gear to be started by the pinion, of an eccentricweight rigid with the pinion, and an annular weight mounted on 5 and rotatable relatively to the pinion.

6. In a starter for engines, the combination with a threaded shaft, a, threaded pinion thereon, and a gear to be started by the pinion, of a. weight carried by the pinion and rotatable relatively thereto, and a 10 spring abutment for cushioning the intermeshing of said pinion and gear.

WILLIAM O. KENNINGTON.

Witnesses:

Z. MI SMITH, F. P- MCDERMOTT, Jr.

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