US681351A - Driving and braking gear. - Google Patents

Description

No. 68!,35I. Patented Aug. 27, I90l. G. F. STUBGESS.

DRIVING AND BRAKING GEAR.

(Application filed Nov. 19, 1900.) (No Model.)

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Nrrnn STATES IATENT FFICE.

GEORGE F. STURGESS, OF LEICESTER, ENGLAND, ASSIGNOR OF THREE- FOURTI-IS TO ALFRED EDWIN HITCHCOCK, JOHN PARSONS, AND CHARLES EDWARD HARE, OF SAME PLACE.

DRIVING AND BRAKING GEAR.

SPECIFICATION forming part of Letters Patent No. 681,351, dated August 27, 1901.

Application filed November 19, 1900. Serial lid 37,060. (N model.)

To (0% whom, it may concern:

Be it known that I, GEORGE FREDERICK STURGEss, engineer, a subject of the Queen of England, residing at The Inglenook,Leicester, in the county of Leicester, England, have invented certain new and useful Improvements in Driving and Braking Gear, ofwhich the following is a specification.

This invention relates to the construction of mechanism for transmitting power rotatively through the medium of a friction-coil engaging with a revolving drum.

One object of the invention is, primarily, to construct a driving and braking gear which shall be capable of being brought into action quickly without shock to the moving parts and which is operated by the circular movement of one of the parts. with respect to another of the parts-for instance, by the rotative movement of the driving-drum being varied 0r reversed with respect to the memher it is driving, so that the brake may be applied at any moment without danger to the mechanism, caused by the momentum in the driven or overrunning parts.

A further important object of the invention is the combination,with the braking-gear, of means for enabling the driving member to become also the brake-operating member. Other objects to be obtained are that the frictional coil-grip shall automatically free itself when the parts come to rest or the motive power is stopped and that the friction-coil shall be tensionless-that is, shall not exert any frictional grip on the moving parts when not required. The driving and braking gear thus generally referred to embodies a coilclutch adapted to apply frictional driving and braking power to the friction-drum of a driven wheel, pulley, orshaft which is mounted to have independent rotation in respect to the coil-clutch and in which a part of the coil is forced into engagement with the flange of the drum by what may be termed a primary pressure, whereupon the drum sets up a complementary or winding action which progressively winds the curls of the coil, thereby acquiring an accumulated or augmented power. This accumulative increasdriving-coil engages or strikes the relatively stationary drum for the purpose of rotating it, but it is more apparent when the overrunning drum, having the propulsive force or inertia of its velocity, strikes the stationary coil for the purpose of braking its move ment.

Anotherobject of this invention is to render the augmentativeaction entirely shockless by first applying the primary pressure or tric tion directly against the recoil or spring nature of the coil-clutch, thereby obtaining a yielding and sensitive attachment or engagement for the coil that prevents jamming under average conditions, and where great velocity, and consequently abnormal aumentative brake force, is generated in the coil by the employment of a friction-support for the stopped coil that will yield to the excess brakepressure, and thereby prevent jamming in any case, a coil-clutch is provided for universal application for power transmission.

The invention consists, primarily, of direct acting and freeing clutches and a coacting operator for the coil-clutch adapted to bring the curls of the coil into engagement with the drum in a circular direction common to the rotary movement, whereby when employed for driving as well as braking the drum the one movement serves for the introduction of the coil to its driving and braking act-ions, therefore combining the features of a coilclutch and a brake-clutch, all as will hereinafter he more fully described, and definitely pointed out in the claims.

In the drawings, Figure l is a section ofa driving and braking gear, in one form or embodiment of my invention represented as applicable as a cycle driving or braking gear, with the hub, axle, and other unnecessary features of the cycle construction omitted. Fig. 2 is a front view of the driving and braking gear, with the brake disk or plate 8, the plate 7, and the cone 6 removed therefrom to better show the interior arrangement of the operating member or sprocket-wheel. Fig. 3 is a detached sectional view of the driven drum. Fig. 4c is a section of the gear with some of the parts omitted to more clearly show the construction of theinterior web or flange of the operating member or sprocket-wheel. Figs. 5 and 6 are sections, respectively, of the gear, with some of the parts omitted or broken away to more clearly show the two positions of the cross-link and clutch-roller during the driving or braking action, respectively. Figs. 7 and 10 are detached views of the eccentricclutch and its connection with the coil-clutch to be described. Fig. 8 is a detached crosssectioual view of the coil-clutch and the crosslink, showing the connections thereof; and Fig. 9 is a side elevation of the coil-clutch and the cross-link.

The gear selected for the present embodiment of my invention shows a construction more particularly adapted for use on cycles, &c., although it will be evident that it may be used wherever the driving, free-running, and braking actions peculiar to the present construction are desirable.

In the drawings the operating member of the gear which controls the action thereof either to drive, to brake, or permit free running is represented as the sprocket-wheel a of a cycle or the like, provided on its inner side with the rib or flange 64. Located within the operating member or sprocket-wheel a and to one side of the rib or flange a. is the drum I), provided on its inner edge with a series of teeth or serrations b and having a chamber 5 for the receptionof the coil-clutch member 0 and a screw-threaded interior portion (6 by which to connect the drum to the hub of the wheel or other part to be operated, and which is not herein shown in order to more clearly display the construction of the gear. A lock-nut (1, having a shoulder d2 to engage the rib or flange a of the operating member or sprocket a and to screw upon the hub of the wheel or other part to be operated, serves to maintain the sprocket-wheel a, the drum, and coil-clutch in their proper assembled relation.

Mounted on the exterior of the fixed cone 6, which is itself internally screw-threaded to engage a fixed part, such as the fixed shaft, (not shown,) is a fixed plate 7, and between the fixed cone 6 and fixed plate 7 is the brake disk or plate 8, normally held stationary with said parts, packing 9 and 10 being interposed between the plate 8, the cone 6, and plate 7, as shown, whereby while under normal conditions the plate 8 is fixed or stationary it esieti may yet move under normal conditions, extreme force tending to turn it, the said plate 8 being also provided with a series of teeth or serrations 8 for a purpose that will hereinafter appear.

As hereinbefore noted, the operating member or sprocket-wheel a is provided with an internal rib or flange a. Said rib or flange is interrupted or has a portion cut out, as more clearly shown in Figs. 2 and 4, such cut portion extending, as shown in Fig. 2, from the edge t to the incline n. Parts of the rib or flange at the cut-away portion are, however, continued around the rib or flange forming the inner and outer ribs in and 1, respectively, so disposed that they extend along opposite sides of the flange a and provide a passage 0 between their opposed ends, Figs. 4:, 5, and 6, and a supporting-shelf Z and m on the sides of said ribs or flanges Z and m for the support and guidance of a roller .2 and clutch plate p, as will more fully appear.

Loosely contained within the chamber b of the drum b is the coil-clutch o, normally out of frictional engagement with the frictionrim 5 of said drum. Pivotally connected to the terminals of the coil-clutch by the pins or studs 4" and q is the cross-link 19, having an upturned end w and projecting onto the cutaway portion of the rib or flange a of the operatin g member or sprocket a, as more clearly appears in Figs. 1, 8, and 9, and interposed between the upturned end to of the cross-link p and the terminal or end of the coil-clutch at q is the clutch-roller z, of sufficient diameter to project beyond the supporting-shelves Z or m to engage the notches or serrations b in the drum or those b in the brake-disk or stationary plate 8, according to the conditions of operation, as will appear.

It should be noted carefully that the clutchroller ,2 always remains between the upturned end w of the cross-link and the end (1 of the coil-clutch, that the roller is wider than the coil, and consequently overhangs, and that when driving forward or when braking the outstanding side of this rolleris firmly gripped and held in the first casebetween the serrated edge of b and the rib Z (see Fig. 5) and in the second case between the serrated edge of the brake disk or plate 8 and the rim m, as in Fig. 6. As the parts I) and a both revolve during the forward drive, it Will be seen that the coil-clutch also revolves at that time; but when the clutch-rolleris gripped between the rib m and the brake disk or plate 8, as the latter is stationary, it will be seen that the coil also is held stationary. Bearing in mind, then, that the clutch-roller z is for the purpose of stopping the end q of the coil-clutch while the end '2" is left free to be moved by the cross-linkp, it will be understood on reference to Fig. 8 that pressure on the incline s of the cross-link 19 will cause the frictional engagement of the coil 0 with the-drum b by pressing out or expanding the end 0 and that IIO pressure on the incline w in the opposite direction will also have precisely the same effect. I

Returning to Fig. 2, it will be seen that the part of the cross-link clutch between the inclines t and n projects into the opening in the flange a of the sprocket-wheel and has a certain amount of longitudinal play therein; also, that the clutch-roller z entirely fills the space between the cross-link and the rim of the sprocket-wheel.

When the drive is forward, by means of the sprocket-wheel the roller is gripped between the serrated edge of b and the rib Z, as shown in Figs. 4 and 5, and the edge if of the opening, Fig. 2, presses on the incline s of the cross-link and causes the coil to expand to frictionally engage the surrounding drum 5, attached to the hub, and consequently to rotate the hub. Should the pressure on the incline s be very heavy, the drive becomes a positive one, as will be obvious. It now the sprocket-wheel is stopped without back pressure being exerted,the hub runs on, and being attached to the drum 2) the serrated edge of the latter carries the clutch-roller forward until it reaches the inclined passage 0, Where it runs out of gear with the serrated edge of b and either remains in the passage 0 if the drum is running at a greater velocity than the operator or sprocket-wheel or runs to the outer side of the rib m and into one of the recesses 8 in the fixed brake disk or plate 8, as shown in Fig. 6, as when the driving sprocket-wheel is stopped Without turning backward. Free wheeling may take place now whether the sprocket-wheel is rotating forward slowly or stopped. When the sprocket-wheel is forced backward while the roller=clutch is held stationary by the disk or plate 8, the incline n of the sprocket-wheel comes into contact with the incline w on the cross-link p and the end of the coil 0 is opened into engagement with the overrunning drum-surface. It should be noted that the drum is rotatingin a direction which opposes the recoil action of the end of the coil. Consequently the friction of the first curl has a self-augmenting frictional action on the remaining curls so long as a circular pressure is applied to the end r directlyagainst the recoil action.

From the construction of the gear and the disposition of parts,as hereinbefore described, and shown in the drawings, it will be evident that for permitting the drum to have free rotary movement after having been driven by the operator or sprocket-wheel Ct the latter is stopped or rotated in the same direction as the movement of the drum, but at a less velocity, and under these conditions the roller-clutch .2 will be carried into the opening 0 between the engagement with the drum 6, although held stationary with the sprocket a, or, if the latter is rotating slower than the drum 1), being carried with it. For forward drivingthat is, for imparting driving power to the drum bthe operating member or sprocket-wheel a is rotated at a speed to overtake the drum b, and this action first causes the clutch-roller z to take position, as shown in Fig. 5, between the flanges b and land secure thereby a purchase to cause the coil to expand by engagement of the inclined edge 8 of the crosslinkp with the inclined edget of the flange a, formed on the interior of the sprocketwheel a. Such action of the parts gives the initial pressure to expand the coil, which thereafter has its other coils further expanded by the augmentative frictional action of the drum b thereon, until the coil friction overcomes the resistance of and drives the drum. The frictional engagement and driving action of the coil and drum relieve thepositive roller-clutch of the greater part of the weight of driving, although the clutch-roller z itself forms a positive drive in case of need, such as by breakage of the coil -clutch or failure of a worn coil to carry the full weight of driving.

For braking the forward free movement of the drum b the stoppage and then back movement of the operating member or sprocket-wheel a first causes the roller-clutch z to move through the passageo onto the opposite side of the flange m into engagement with the serrations or teeth 8 on the brake disk or plate 8, as shown in Fig. 6, and then to cause the primary pressure for expanding the coil-clutch by means of the cross-link p by engagement of the inclined end w of the cross-link with the incline n, as indicated in Fig. 6, whereupon the augmentative winding action due to the frictional engagement between the drum 1) and the first curl of the coil ensues, as hereinbefore indicated. Should the necessary brake force be excessive, in order to stop the rotation or slacken the rotation of the parts of the drum b, as in coasting on steep grades, the sudden engagement of the coil-drum might cause a shock sufficient to break the machine or upset the rider. Under such conditions the brake disk or plate 8 yields to the excessive brake-pressure and moves between the fixed plate 7 and fixed cone 6 until the frictional resistance has reduced the speed, and consequently the brakepressure, to normal, whereupon the disk 8 stops and the moderate brake-pressure between the coil and the'drum bis resumed, thereby avoiding all shock. The drum 1) is provided in one of the walls of the chamber b with a circular recess 12 into which may be fitted what I will term a strip or eccentric brake f, and the first curl of the coil-' clutch is also provided with a recess f eccentrio to the circle of the coil to correspond to the eccentricity of the strip-clutch f. The

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ends of the strip-clutch f approach each other on either side of the end of the crosslink 19 and abut against the same, from which it will be seen, by reason of the inclined or curved contour of the edges of the cross-link 29, that when the latter is turned to expand the curl of the coil it will act to move the strip-clutch and to turn it more or less, according to the degree of movement given the cross-link, so that the eccentricity of the strip-clutch will assist the cross-link in expanding the first curl of the coil to produce the initial pressure and cause frictional engagement with the drum 1?. When inactive and therefore inert, the coil-clutch confines the cross-link p and strip-clutch f to their initial and free positions, due to the contractile force of the coils.

Though described herein mainly in regard to the driving and braking gear of veloci-- pedes, it must be understood that this invention is applicable to any form of power transmission through a friction coil-clutch, as between a pulley and a line-shaft or on hoistger of breakage, due to the momentum of the overrunning parts. By opposing the applied pressure to the recoil action of the coil the advantage is obtained that the coil will always free itself when the applied pressure is removed.

Having now particularly described and ascertained the nature of my invention and in what manner the same is to be performed, I declare that what I claim is 1. In a coil-clutch mechanism, the combination with a driver, a friction-drum rotatable in either direction, of an inert coil arranged to frictionally engage said drum to either drive or brake the same, means to apply a yielding primary or initial pressure directly against the recoil action of the coil to obtain a shockless transmission of power, said means being operative to apply the primary pressure against the recoil action to drive the drum on movement of the driver in one direction and operative to apply said pressure to brake the drum on movement of the driver in the opposite direction.

2. In a coilclutch mechanism, the combination with the driver, a friction-drum independently rotatable in either direction, of a friction-coil, means to move or expand the coil at both ends into engagement with the friction-drum to drive the same upon the application of pressure directly against the recoil action of the coil by movement of the driver in one direction and to expand the coil at both ends into engagement with the friction-drum to brake the same by movement of the driverin the opposite direction so that the recoil action of the coil may free the coil upon stoppage of the pressure thereon by the driver.

3. In brake mechanism of the character described, the combination with a rotatable drum of the primary spring-coil brake, means connected to the spring to initially expand the coil to apply the primary spring-coil brake, and a secondary brake comprising a retarded brake-disk, a fixed support having thesaid retarded brake-disk yieldingly held therein for the purpose of reducing the shock when the brake is applied-under excessive brakepressure, substantially as herein described.

4. In adriving and braking gear, the combination of an operating member, a drum rotatable independently of said operating member, a coil-clutch interposedbetween the operating member and the drum,means carried by the operating member to initially expand the coil against its recoil action upon rotation of said member in one direction into engagement with the drum for driving said drum, and to expand the coil into engagement with the drum upon rotation of said member in the opposite direction to brake said drum.

5. In a driving and braking gear, the combination of an operating member, a drum rotatable independently of said operating member, a coil-clutch interposed between the operating member to initially expand the coil against its recoil action upon rotation of said member in one direction into engagement with the drum for driving said drum, and to expand the coil into engagement with the drum upon rotation of said member in the opposite direction to brake said drum, and a brake-disk in operative connection with the coil to assist in braking the drum upon excessive brake-pressure.

6. In. a driving and braking gear, the combination of an operating member or sprocketwheel, a drum rotatable independently thereof, a coil-clutch interposed between the operating member and drum and a crosslink pivotally connected to each end of the coil the angular movement of which link opens the spring into frictional engagement with the drum, and devices operative on movement of the driver in one direction to actuate the link and open the spring into engagement with the drum to drive the same and operative on movement of the driver in the opposite direction to actuate the link and open the spring into engagement with the drum to brake the same.

7. In a driving and braking gear, the combination of an operating member, a member rotatable independently thereof, a coil-clutch interposed between said members, a cross link connected to the ends of said coil to expand the same against its recoil action on angular movement of said cross-link, a rollerclutch in operative engagement to the crosslink, and means to move or turn said link to initially expand said coil-clutch.

8. In a driving and braking gear, the combination of an operatingmember, a member rotatable independently thereof provided With serrations or notches, a coil-clutch interposed between saidmembers, a cross -link connected to the ends of said coil to expand the same against its recoil action on angular movement of said cross-link, a roller-clutch in operative engagement to the crosslink and adapted to engage the serrations or notches, and means to move or turn said link to initially expand said coil-clutch.

9. In a driving and braking gear, an operating member, a member or drum rotatable independent of said member, a coil-clutch interposed between said members,a strip-clutch embraced by a coil of said coil-clutch, and means to expand the coil and move the stripclutch to force the coil into frictional engagement with the drum.

10. In a driving and braking gear, an operating member, a member or drum rotatable independent of said member, a coil-clutch interposed between said members, a stripclutch embraced by a coil of said coil-clutch, and a cross-link connected to the coil and engaging the strip-clutch to expand the coil and move the strip-clutch to force the coil into frictional engagement with the drum.

GEO. F. STURGESS.

Witnesses:

THOMAS Sco'rr, WALTER W. BALL.

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