US2512450A - Operating lever mechanism for rotary hand brakes - Google Patents

Description

June 20, 1950 K. WILLIAMS 7 2,512,450

OPERATING LEVER MECHANISM FOR ROTARY HAND BRAKES Filed on. s, 1947 Patented June 20, 1950 A. i;

PATENT oFFice f ROTARYIHAND BRAKES V .v 3 This invention relates to improvementsin hand brakes of the swinging lever-operatedtype es;- pecially adapted foruse on; railway cars. One object of the invention istoprovideac: tuating means-for the rotary, chainwinding drum of a hand brake mechanism, comprising ing operating lever, a ratchet wheel'rotatablewith the drum, anda sliding pawlengageablewith the ratchet wheel for operatively connecting; the lever to the ratchet wheel to rotate the drum in chain- Winding direction, wherein the lever in being swung in chain-winding direction pulls the pawl into engagement with the ratchet wheel,. an d swinging movement of the same in a reverse direction forces the pawl out of engagement, A further object of the invention is'to provide a hand brake mechanism comprising a chainwinding drum and meansfor transmitting'rotary motion to the drum to wind the chain thereon, including a drivi s aft, a r tche w el, ie to the shaft, -a swinging-link -J 'ournaled n the shaft, an operating lever swingingly connected to said link, a pawl engageable with said ratchet wheel for locking the lever to the wheel to rotate the latter and the chain-winding drum, and an eccentric connection betweenthe lever and pawl for effecting movement of the pawl into and cut of engagement with the ratchet wheel as said lever is swung in reverse directions. I r A stilliurther object of the invention is to provide a mechanism as set forth in the preceding paragraph, wherein swinging movement'of the lever is about a horizontal axis, thereby providing for automatic disengagement of the pawl from the ratchet Wheel when the lever is droppedto pendent position and maintaining thepawl dis; engaged while the lever is insaid pendent posi;

tion. I o

Other objects of the invention will more clearly appear from the description and claimshereinafter following. h V

In the accompanying drawingforming a part of this specification, Figure l-is "a side eleva'tional view of a hand brake mechanism, illustrating my improvements in connection therewith, said view showing the brake mounted on the end wall of a railway car. Figure 2 is a vertical sectional view, corresponding substantially to the line 2--2 of Figure 1. Figure 3 is an elevational view of the operating lever mechanism and cooperating ratchet wheel illustratedinFigure- 1, showing in dotted lines the positions the parts assumeatthe initiatio of the upstroke; of-the lever,.-and in i l l hst sitihn s med at h ..;e. a; 9 said upstroke. Figure 4 is an elevational view of the locking pawl of my improved mechanism, looking from the left in Figure 1. Z My-improved handbrake actuating means; as illustrated in the drawing, is shown as applied to a hand brake of the power-multiplying type,

enclosed in a housing; Ill mounted on the vertical end wall I l off-1a railwaycar. The handbrake illustrated-is of the rotary drum type, compris ing a, drum [Lonwhichthe-brakeflghainflriot shown) is wound. The drum is fixed to the usual -horizontal,shaft l3 suitably jqurnaled in the. hou n :W s.-- The: sh t-U Be r le wheell4 @whichis-fixed thereto-and is driven b y amnion-i5 fixed to ascend shaft is mounted in the housingbelow .the shaft, l3 and having its opposite ends; journaled the housing walls The shaft l5 also carries the usual ratchet-wheel ll, with which a, sliding-spring-pressed locking. dog [8 cooperates to hold the ratchetl wheel against rotation in chain-unwinding fd The wheel l1, isarranged within housi Ii],- being f xed-to the shaft Hi adjacent to'th'pinio'n IS, 'A trip lever 19, of well-known iorm, is ployed for actuating theilocking dog-totl rowfthe same into andcut of engagement with the ratchet ee -WI In carrying -eo ut my invention, I provide, means for rotating the shaft it which is geared to the chaingewinding drum l2, 'co mprising broadly a lever A,a link B swingingly supportingthe lever A-on the shaft IS, a ratchet Wheel 'C fixed to the shaft- I6, and a -sliding locking pawl D carried-by the link B and operatively connected to'the lever to 1 be .actuated thereby; and look} the sam'eflo' t e ra h wheel 0- v; 7i mounted on s artan -Th ta he wh l. 1-, Q t vsimi l w h e thhded ei fi r the housing [0, As shown, the ;wheel"Chas a central hub. member 29 projecting from O posite sides thereof and throughwhich the shaft extends, The wheel C isfigged to the shaft any suitable manner, the hub member; being prefer-,- ably .providedvwith an axialsopeninguof sql tre os eh io izahd t .mrt mcf t shaft l5 hwh hth Whe l i mo n Dehehi ki h square cross. section to f lt said opening};

The link B comprisesa pair of laterally sp ced arms Zl-Zl joined by a transverse web 22 near t ew e d th f-amih hmier;. hq e e arms 2l-2. are Tslightly;;.enla rged to prev e round head"portions23"2 3. l-TThelarms 2] are d s shdfa -hh oi 'it s'id 'f if C, the head ;-portio'ris 2 35-23 Ithereof being name I the projecting portions" 'of' the of the ratchet'wheel, each head.,being with a suitable bearing opening z i'for p pose The lin k B is held insposition on the wheel C by a nut 3 2 th'rea ded on the ntimat portion 33 of thefshaft,lt, with an interposed na ihrhhe thi h P r .9 a; htr d d at sa ink as gure .15: Zlhiasirrumlihe u de rtiqhzs mprises aterall extending short arms on the head'portions'23-23 short arm 26 at its upper end. The pivoted upper end portion of the lever A is embraced between the lower ends of the arms 2l2l oi the; link 5 and is supported by a pivot pin 21 extendin through suitable openings in the lever and arms of the link.

The locking pawl D is in the form-015a short bar having a tooth 28 at its upper end engageable with the teeth of the ratchet wheel C. The pawl D is guided for sliding movement in the stirrup 25 of the link-B and is slotted lengthwise between its ends, as indicated at 29, to provide clearance for the ratchet wheel, the slot Hextending entirely through the pawl and having its upperend terminating at the-tooth28. The lower end portion of the pawl is reduced in width, as shown in'Figure 4, said portion of reduced width being transversely enlarged-to provide a head 30. This head of the pawl is pivotally connected to the forked arm 26 of the lever A, being engaged within the fork of said arm and connected thereto by a pin 3| extending through suitable openings in the head 30 of the pawl and the fork of the lever.

In the operation of my improved mechanism, in applying the brakes the operating lever A is oscillated, thereby effecting intermittent rotation of the ratchet wheel 0 and rotation of the drum 12 to wind the chain thereon. In swinging the lever A clockwise, as shown in full lines in Figure 3, there is also pivotal movement of the lever on the link B, thereby swinging the arm Ilii clockwise, as shown in dotted linesin Figure 3, and pulling'the tooth 28 of the pawl D into gripping engagement with the teeth of the wheel C, the pawl being directed in this movement by the guide stirrup 25 of the link B. Thus as the lever A is swung from the position shown in Figure 1 clockwise toward the full line position shown in Figure 3, rotationis imparted to the shaft IS and the drum l2. During the return or counter-clockwise stroke of the lever, the lever first pivots on the link B, thus withdrawing the tooth 28 of the pawl D from engagement with the teeth of the ratchet wheel Cto permit the return of the lever to the position shown in Figure 1 while the wheel C remains stationary, 'held in that position by locking engagement of the dog I8 with the ratchet wheel I'll Oscillating swinging movement of the lever A is continued until the brakes have been applied to the desired extent. v

As will evident, the leve-r A is in the pendent-position shownin Figure 1,] it holds the tooth 28 of thepawl D disengaged from the teeth of the ratchet wheel C, thereby permitting free rotation of the latter and quick release of the brakes when' the locking dog [8 is disengaged in the usual manner from the ratchet wheel" I! by thetrip leverlS.

I claim: g l

'1. In a hand brake-mechanism, the combination with a rotary chainewinding member or the like, of means for transmitting rotary motion to said member to wind the chain thereon including a rotatable ratchet wheel, a swinging supporting member mounted for rotation about the axis of rotation of said ratchet wheel and extending radially therefrom, a pawlengageable I with said ratchet wheel on the side away from said supporting member and extending generally tangentially of said ratchet wheel and parallel to' said; supporting member; an :'operating bell crank lever swingingly connected to and constituting an extension of said supporting member and pivotally mounting said pawl for moving it into and out, of engagement with said ratchet wheel and rotating the same by force applied to the side opposite the side where it is engaged by said pawl, and guide means extending from said swinging supporting member and holding said pawl for movement tangentially of said ratchet wheel;

2. In a hand brake mechanism, the combination with a rotary chain-winding member or the like, of means for transmitting rotary motion to said member to wind the chain thereon including a" rotatable ratchet wheel, a swinging supporting member mounted for rotation about the axis of rotation ofsaid ratchet wheel and extending radially therefrom, a pawl engageable with said ratchet wheel on the side away from said supporting member and extending: generally tangentially of said ratchet wheel and parallel to said supporting member, an operation bell crank lever swingingly connected to and constituting an extension ofsaid supporting member and pivotally mounting said pawl for moving it into and out of engagement with said ratchet wheel and rotating the same by force applied to the sideopposite the side where it is engaged by said pawl, andguide means in the form of a stirrup extending from said swinging supporting member and slidably holding said pawl in operative relation to-said ratchet wheel.

In a hand brake mechanism, the combination with a rotary chain-winding member or the like, of means for transmitting rotary motion to said member to wind the chain thereon including a rotatable ratchet wheel, a swinging supporting member mounted for rotation about the axis of rotation of said ratchet wheel and extending radially therefrom, a pawl engageable with said ratchet wheel on the side away from said supporting member and extending generally tangentially of said ratchet wheel and parallel to saidsupporting member, said pawl-being slotted longitudinallyand the'teeth of said ratchet wheel extending into the slot, and an operating bell crank lever swingingly connected to and constituting an extension of said supporting member in operative engagement with said pawl for moving'the sameinto and out ofengagement with said ratchet wheel and rotating the same by force applied to the side opposite the side where it is engaged by said pawl.

' KEITH WILLIAMS.

REFERENGES siren Thefollowing references are of record in th file of this patent:

Ul lII-ED' STATES PATENTS Number Name Date 82,295 Day Sept. 22. 1868 204,299- Cross 4.; May 28, 1878 219,740; Kirkwood" Sept. 16, 1879 1,112,998-- Granlund Oct. 6, 1914 l aorta-ion PATENTS,

Number Gountry' Date 1 267.19% -GreatBritain Mar. 3, 1921

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