US2269004A - Holding and releasing mechanism for railroad hand brakes - Google Patents

Description

' Ja 6, 1942- I H. D. BREEN 2,269,004

HOLDING AND RELEASING MECHANISM FOR RAILROAD HAND BRAKES vFiiecl April 1, 1940 3, Sheets-Shes: 1

Jan. 6, 1942. H. 'D. BREEN 2,269,004

HOLDING AND RELEASING MECHANISM FOR RAILROAD HAND BRAKES Filed April 1, 1940 3 Sheets-Sheet 2 Jan. 6, 1942. H.'D. BREEN 2,269,004 HOLDING AND RELEASING [MECHANISM FOR RAILROAD HARD BRAKES Filed April 1, 1940 3 Sheets-Sheet 3 Patented Jan. 6, 1942 u u STAT YHOLDINGAND RELEAsINGMnoHANIsM-Foit RAILROAD HAND BRQKES Henry D; Breen, Chicago, Ill., assigiionto Union l Asbestos &-Rubber (lompamnflhica'go, 111,, a

corporation cf Il-li nois 1 "AppIicat'ionApril 1; "1940, serial No. 327,184

' '13 claim 4.01. 188 -811) This invention relates to improvements in holding and releasing mechanism' forf hahd brakes.- The object of the invention is to provide an improved and simplified holding mechanism for hand brakes.

Hand brakes for railroad cars are subjectedto numerous conditions of service which impose and releasing rigorous requirements upon. the type of struc ture which is employed to operate the brakes;

The operating mechanism for the brakes usually is mounted upon the exterior of the end of each railroad car. The operating mechanism must be accessible and accQrdingIyQcanbe onlypartially housed. The parts thereforeare exposed .to all. varieties of weather conditions and theconstant presence of dust, cinders and soot in ,theair Severe stresses are imposed by the operation of the braking through which the train moves.

mechanism and theshocks. of travel, and many other factors are encountered which impose special requirements of construction which must nevertheless render the brakeat all timesavailable to service and positive of operation! In the operation of hand brakes on railroad cars it is frequently necessary to apply the brakes suddenly by a quick rotation of thesh'and wheel by which the brakes are brought into braking position, and it is desirable .tha'tduring operation the hand wheel be automatically held againstre-j verse movements. When the brakes arereleased' it is also desirable thatthe holding mechanism by which the brake'andhandwheel isheld'in braking position, be "completely and quickly re-- leased. It is also desirable-and frequently neces*-- sary that either of these operations beaccomplished by the use of a single hand bythe brakeman, who may require the use of hisfoth'er hand to retain his hold to the hand-holds by which ihe maintains an elevated position upon ;the endiof the car. It is thereforenecessary thatthe brake holding and releasingmechanis'm be capable of v being readily set into either holding or releasing position by one hand which may then be immediately devoted to the operation of the brake hand wheel by which the brakes are set and released.

It is the object of this invention to provide a holding and releasing mechanism which 'will meet these requirements of a serviceablebrake and which possesses other advantages in con-j.

struction and operation. v

A further object of the invention is to provide a holding and releasing mechanism for; hand brakes which is simplein construction, sturdy;

has 'few'm'oving parts, and is not capable of get ting out of adjustment. 7

A further object of the invention is provide a holding :and releasing mechanism for: hand brakes in which all moving; parts swing upon" simple pivots, and there are nosl'idingmove ments'or other movements in whichexposedlsurfaces of the'moving .parts areropen to them:- oumula'tion of dirt and other. foreign matter which may'interfere withthe'operationof Ithe mechanism. i

A further object of the invention is to provide a holding and releasing mechanism for hand brakes which has only two manual controls-,ithe

hand wheel by which the brake is operated, and

a simple hand lever-for settingthe 'mechanism intoeither holding or releasing position. I

A further object of theinventi'on' is to provide a mecha'nismofthis characterinwhich operation of the trip lever for setting themechanism into either holding or releasin'g position will-positi-vely operate the mechanism Ibut nevertheless operation of the hand wheel and movement of vide a holdin and releasing mechanism for hand the mechanism will 'not be-transniitted'lnto forciblemovement of the-hand lever on. the exterior of the mechanism housing except for J slight 0S-' cillation thereof. I i. Aiu'rther object of the invention isto-probrakes inwhich the holding pawl, by which the ratchet is locked in. holding position,is not forcibly disengaged bythe" operator,; but is permitted to disengage itself upon manipulation-of the hand wheel and without the application of force to the pawl mechanism; i

A further object of the invention is to provide a holding and releasing mechanism" for hand brakes which-is susceptible of construction in many forms. without modification of the principle of the invention, and which lends itself to terials ofmanuiacture.

construction from the ordinary and familiar ma- In.addition11to the objects hereinaboyie nuemerated, additional objects, advanta es: and can porating this invention taken on the line 2-2 of Fig. 1 looking in the direction of the arrows;

Fig. 3 is a vertical sectional view of a fragment of the housing enclosing the mechanism of this invention, taken on the line 33 of Fig. 2, showing the mechanism in elevation with the parts in holding position;

Fig. 4 is a View similar to that shown in Fig. 3, with the respective parts shown in holding position, but with the ratchet turned slightly forward and the pawl riding upon the high point of the ratchet teeth as the hand wheel is being turned and the brake being applied;

Fig. 5 is a similar view in vertical section of the mechanism of this invention with the parts in the respective positions occupied when the operating hand lever has been swung into releasing position; i

Fig. 6 is a perspective view of the operating shaft and operating cams of the hand lever by which the holding and releasing mechanism is set into either holding or releasing position by the brakeman;

The embodiments of Figures 9 to 13 operate in. substantially the same manner as that of Figures 1 to 8 as described above. The only difference is that the springs I33 replace the weight 33 and tend to move the pawl to its release position shown in each of Figures 9, 11 and 12 when the lever 50 is swung to the right as shown in dotted lines in these figures. I

Fig. '7 is a perspective view of the counterweighted pawl element of this invention;

Fig, 8 is a perspective View of the pivoted pawl carriage;

Fig. 9 is a fragmentary sectional view of the holding and releasing mechanism in modified form, in which a spring is employed in place of the counter-weight on the pawl element;

Fig. 10 is a fragmentary top plan view of the end'of the pawl carriage in which the spring operated pawl of Fig. 9 is pivotally mounted, the view being taken on line |0-l'0 of Fig. 9;

Fig. 11 is a View similar to that in Fig. 9 of another:modified form of the holding and releasing mechanism of this invention with a springoperated pawl;

Fig. 12 is a view similar to that shown in Fig. 9 of a third modified form of spring-operated pawl;

. Fig. 13 is a vertical sectional view through the pawl and pawl carriage of the modified form of this invention shown in Fig. 12, taken on the line l3l3 of Fig. 12,

Similar reference characters designate corresponding parts throughout the several figures of the drawings.

The construction of the mechanism Referring to the structures shown in Figs. 1-8, inclusive, showing a preferred form of an embodiment of this invention, Fig. 1 shows a fragment of the end of a box car indicated by the reference numeral 20. Secured by the bolts 2| to the end of the box car and near the top thereof is the housing 22 containing the holding and releasing mechanism for, the hand brake. In addition to the holding and releasing mechanism of this invention, this housing contains a suitable sheave indicated by the numeral 23, upon which is wound afiexible brake chain 24. This chain is secured to the end of a rod 25 which runs to the bottom of the car and is there suitably linked to the conventional brake-operating mechanism which is standard equipment on freight cars, and which forms no part of this invention.

The sheave 23 is driven. by a large gear indicated by the numeral 26, which is in turn driven by the pinion 21 secured to the shaft 29 which is operated by the hand wheel 28. Thus by operation' of the hand wheel 28 the sheave may be turned and the brake chain 24 wound thereon. The use of the small pinion 21 enmeshed with the large gear 26 enables the brakeman to apply to the chain 24 the power necessary to operate the brakes merely by application of manual force to the hand wheel 28.

The handwheel shaft assembly The handwheel shaft assembly A, best shown in Fig. 2, is driven by the handwheel 28, mounted upon the end of the shaft 29, and through rotation of the pinion 21 imparts the power necessary to rotate the brake chain sheave 23. The ratchet 30, which forms part of this assembly A, is also keyed to the shaft 29 and to the pinion 2'! to provide control of the shaft against reverse movement. The shaft 29 is rotatably supported by a gudgeon in the rear wall of the housing 22, and runs through the front wall of the housing where it is suitably journaled, to project a substantial distance beyond. The entire assembly rotates as a single unit, its movement corresponding to the movement of the handwheel 28.

The pawl element The pawl element B, shown in perspective in Fig. 7, is made in the form of a counterweighted unit, pivoting upon the central bearing 32, by which the pawl element rocks upon the pivot 3| (see Fig. 3). The counterweight 33 is suspended upon one arm of the element. The other arm projects in the opposite direction to provide the pawl tooth 34 near the bearing 32, and the pawl control finger 35 extending a short distance beyond and above the pawl tooth. The pawl tooth 34 is designed to form a detent for the ratchet 30.

The pivoted pawl carriage The pawl element B is designed to be pivotally supported within the pivoted pawl carriage C which is shown in Fig. 8. This carriage is built in the form of a hollow frame, composed of the side walls 36 and 31, joined by the top cross member 38 and the bottom cross member 39. The cross member 39 is formed with the boss 69 along its length to give added strength to the member. The carriage is pivotally supported within the housing 22by the gudgeons 4|. The side walls 36 and 31 are perforated to form bearings 42 at the end most remote from the gudgeons 4| to receive the pivot 3|, by which the pawl element B is supported within the carriage C.

The carriage side wall 36 bears the spur 43 directly above the gudgeons M. The purpose of this spur will be explained hereafter.

As best shown in Figs. 3, 4 and 5, the pawl carriage C is pivotally mounted within the housing 22 overthe handwheel shaft assembly A and in such relation thereto that when the pawl element B is mounted within the carriage, the pawl tooth 34 lies directly over the axis of the shaft 29.

The operating hand lever shaft The operating hand lever shaft D is shown in perspective in Fig. 6. This shaft, like the handwheel shaft 28, is supported in the back wall of the housing 22 by the gudgeon 45, and projects shaft. The rocker 41, shown in Fig. 1 and inv phantom in Figs. 3, 4 and 5, is' mounted outside of the housing 22. Its two ends are formed into the fingers or stops 48 and 49, between which the operating handlever or trip lever 50 moves. swingably upon the hand lever shaft D. The

trip lever 50 thus has a limited range of free movement between the rocker-stops 48 and 4-9, beyond which it moves the rocker 4i! and imparts movement to the shaft. This free movement is over a short range above theaxis of the shaft D, so that any movement beyond the free range is aided by the weight of thehand lever 50,

and when swung into its extreme positions, the weight of the hand lever thus insures that sub-- stantial leverage will be exerted upon the shaft D solely by the weight of the lever itself. For

this purpose the hand lever 50 is given substantial length and weight.

It is to be noted that the hand lever shaft D is shorter than the hand wheel shaft 29,'so that the rocker 41 andthe hand'lever -50 aremounted and move between the handwheel 28 and the housing 22, and are thus protected by the handwheel against accidental contact with any body that might tend to move them.

The shaft D is formed with the cam '51 and the trip finger 52, intermediate its length. When the shaft D is in position within the housing 22 the cam 5| rides over the control finger 35 upon the pawl element Band the trip finger 52 swings in an arc which is intersected by the spur 43 on the pawl carriage C. The operation of these parts will be explained in detail in the description of the operation of this mechanism.

Within the housing 22 and preferably made integral with the rear wall thereof is the boss or stop 53, upon which the pawl carriage C rests in its lowermost position. Upon the upper side wall of the housing is the stop 54 which obstructs movement of the pawl counterweight 33' beyond the range necessary for operation of the mechanism, and thus prevents any violent movement of the parts from swinging the pawlcarriage C out of operative position. On the other side wall-of the housing the stop '44 similarly limits the range of movement :of the trip finger 5 shaft D upon which it is- 52 and the hand lever mounted.

Alternative forms of structure of the boss I55, and the pawl element terminates beyond the pivot I31 in the finger I56. ,Between the .boss I55 and the finger 15.6 is a compressed coil spring I33, which forces the pawl tooth 1 34 upward whenever the pawl control .finger 13 5 is free of the projection of the cam 5i.

In the formshown in Fig. 11, the pawl element terminates in the ear I51, and another ear I58 is formed on the side wall of the housing 22. These ears are connected by a spiral spring I33 which forces the pawl tooth l34'upward.

The form shown in :Figs- 12 and 13, varies slightly from the form shown in Figs; 9 and 10 in the locationof the finger I59 uponthe pawl element and the; boss [60.11pm the pawl car.- riage. between which the coil spring l33fis mounted to lift. thepawl tooth I34. In each of the forms the housing is provided with :stops I53 and I54 to limit the range of movement of the pawl carriage.

Operation of the mechanism Referring to the form ;of the invention shown in Figs. 1-8, the operation is as follows: With th ere'spective parts in the positions shown in Figs. land 3,; and the trip lever in, holding position, and' the brake not applied, the brake can be applied merely by rotating the ,handwheel 2.8..in clockwise direction. This rotation of the handwheel rotates the entire shaft assembly A and through the pinion 21. rotates the sheave gear. 26 and ,thesheave 23., shorteningthe brake chain24. T 1

As the han'dwheel .28 is rotated, the pawl tooth 34 successively enters the notches'between'the successive teeth on the ratchet 30 and serves as a detent to prevent reverse movement of the sheave and the handwheel shaft assembly A under the pull of the brake chain 24. ,As the handwheel is rotated vand the high tooth on the ratchet 30- forces the pawl tooth 34 out of the notch between the high tooth and the following tooth, the pawl element '3 cannot swing about th pivot 3| upon' which it is mounted within the pawl carriage C because the hand lever cam 51 obstructs any, upward movement of thepawl control finge'r 35. The entire pawl carriage C therefore swings upward upon its pivot 4|; thus permitting the ratchet tooth .to' clear the pawl tooth 34, as shown in Fig. 4. As soon. as the high ratchet tooth has cleared the pawl tooth 34, the weight of the pawlfcarriage C immediately forces the .pawl tooth intofthe next notch. 'Thus, as the handwheel is rotated in a clockwise direction, the pawl tooth '34 clears each succeeding tooth upon the ratchet 30. and effectively prevents-reverse movement of the handwheel shaft asb y Should the pawl tooth' 34. not drop into the ratchetnotch, downward pressure upon the trip lever 50 against the stop 49 upon the rocker 41 will rotate the hand lever shaft assembly D, the cam 5! will force the pawl control finger 3'5 downward, ,and'the trip finger-52 will bear against the spur 43 and swing the pawl carriage C downwardabout its pivot 4|, and thusforce the pawl tooth 34 into engagement with, the ratchet 30. f

' To release the brake, the. .trip lever 50 is swung in a clockwise direction into the. intermediate position indicated in dotted lines in Fig. 3, and rests against the stop 48 upon the rocker 47. Force could be'applied to the trip lever in this position to swing it into the final position indicated in dotted lines in Fig. 3, but because of the pressur of the high ratchet tooth upon the pawl tooth 34, no movement of the pawl would'be therebyeffected, there being no positive connection between the hand lever shaft D and the pawl element B. However, if the triplever remains in the intermediate position indicated in Fig. 3, any slight movement of the handwheel 28 in clockwise directionwill release the pressure of the ratchet tooth upon the pawl tooth .34, and the weight of the hand' lever .50

I against the stop 48 of'the rocker 41 will swing the hand lever shaft .13 in a clockwise ldirectio'n,

thus swinging the cam 5| and the :tripfmge'r 52" out of range ofthe pawl control finger 35 and the pawl carriage spur 43, and the pawl counterweight 33 will immediately lift the pawl tooth 34 clear of the ratchet, until the parts occupy the respective positions indicated in Fig. 5, when the mechanism is completely released. It will be noted that the pawl carriage C makes no movement during this operation, but rests within the housing upon the boss 53.

It is to be noted that when the trip lever 50 is left in the intermediate position indicated in Fig. 3, and the handwheel is turned slightly clockwise to release the pawl tooth 34 from the ratchet 30, the further movement of the trip lever 50 is caused entirely by its own weight, as the trip lever is free to move between the stop 48 and the stop 49, and no movement of the other parts of the mechanism forces the trip lever to move. This feature of the structure prevents any forced movement of the trip lever which might endanger the hand of the operator.

In order to restore the holding and releasing mechanism into condition to control the handwheel ratchet 30, it is merely necessary to swing the trip lever 50 counterclockwise, whereupon its weight upon the stop 49 of the rocker 41 will swing the hand lever shaft D in the same direction and force the cam 5| into contact with the pawl control finger 35, restoring the parts to the condition shown in Fig. 3, whereupon the mechanism is in condition for application of the brakes.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A holding and releasing mechanism for a hand brake comprising a ratchet, a pivoted pawl carriage above said ratchet, a pawl pivotally mounted upon said pawl carriage and normally moving with said pawl carriage, manually controlled means engaging the pawl normally to constrain it to move with said carriage and movable to a position to permit movement of said pawl independently of said carriage, and means to move said pawl out of engagement with said ratchet whenever said means is in a position such that the pawl is capable of independent movement.

2. A holding and releasing mechanism for a hand brake comprising a ratchet, a pivoted pawl carriage above said ratchet, a pawl pivotally mounted upon said pawl carriage, a counterweight upon said pawl tending to lift said pawl out of engagement with said ratchet and tending to force said pawl carriage toward said ratchet, and means to permit said pawl to pivot in said pawl carriage.

3. A holding and releasing mechanism for a hand brake comprising a ratchet, a pivoted pawl carriage above said ratchet, a pawl pivotally mounted upon said pawl carriage, a counterweight upon said pawl tending to lift said pawl out of engagement with said ratchet and tending to force said pawl carriage toward said ratchet, and manually controlled means to permit said pawl to pivot in said pawl carriage.

4. A holding and releasing mechanism for a hand brake comprising a ratchet, a pawl carriage pivoted above said ratchet, a pawl pivotally mounted upon said carriage, and a manually controlled means to move said pawl about its pivot on the carriage independently of movement of the carriage to engage or disengage the ratchet, the pawl being movable with the carriage to permit movement of the ratchet in one direction.

5. A holding and releasing mechanism for a hand brake comprising a ratchet, a pawl positioned to engage said ratchet, a pivoted pawl carriage holding said pawl in engagement with said ratchet, manually controlled means to free said pawl for movement relative to and independently of said pawl carriage and out of engagement with said ratchet, and automatic means tending to move said pawl on said carriage in a direction to disengage said ratchet when said manual means has been operated to free said pawl.

6. A holding and releasing mechanism for a hand brake comprising a ratchet, a pawl carriage, a pawl pivoted upon said pawl carriage, means upon said pawl carriage tending to force said pawl out of engagement with said ratchet, and manually controlled means whereby said first means may be rendered inoperative.

7. A holding and releasing mechanism for a hand brake comprising a ratchet, a pivoted pawl carriage, a pawl pivotally mounted upon said pawl carriage, and manually controlled means selectively to confine said pawl to movement with said carriage or to free said pawl for movement independently of said carriage.

.8. A holding and releasing mechanism for a hand brake comprising a housing, a ratchet rotatably mounted within said housing, a pawl carriage pivoted within said housing, a pawl pivoted upon said pawl carriage and movable therewith, disengaging means upon said pawl to disengage said pawl from said ratchet, a trip lever shaft rotatably mounted within said housing and projecting therefrom, a trip lever mounted upon said shaft and without said housing, and a cam upon said trip lever shaft operated by said trip lever and engaging said pawl to render said disengaging means inoperative.

9. A holding and releasing mechanism for a hand brake comprising a housing, a ratchet rotatably mounted within said housing, a pawl carriage pivoted within said housing, a pawl pivoted upon said pawl carriage and movable therewith, a counterweight upon said pawl to disengage said pawl from said ratchet, a trip lever shaft rotatably mounted within said housing and projecting therefrom, a trip lever mounted upon said shaft and without said housing, and a cam upon said trip lever shaft operated by said trip lever and engaging said pawl to render said counterweight inoperative.

10. A holding and releasing mechanism for a hand brake comprising a housing, a ratchet rotatably mounted within said housing, a pawl carriage pivoted within said housing, a pawl pivoted upon said pawl carriage and movable therewith, spring means upon said pawl to disengage said pawl from said ratchet, a trip lever shaft rotatably mounted within said housing and projecting therefrom, a trip lever mounted upon said shaft and without said housing, and a cam upon said trip lever shaft operated by said trip lever and engaging said pawl to render said spring means inoperative.

11. A holding and releasing mechanism for a hand brake comprising a housing, a ratchet rotatably mounted within said housing, a pawl carriage pivoted within said housing, a pawl pivoted upon said pawl carriage and movable therewith or independently thereon, disengaging means upon said pawl to move said pawl independently of said carriage and to disengage said pawl from said ratchet, and manually controlled means to render said disengaging means inoperative.

12. A holding and releasing mechanism for a hand brake comprising a housing, a ratchet rotatably mounted within said housing, a pawl carriage pivoted within said housing, a pawl pivoted upon said pawl carriage and movable therewithor independently thereon, disengaging means upon said pawl to move said pawl independently of upon said pawl carriage and movable therewith or independently thereon, disengaging means upon said pawl to move said pawl independently of said carriage and to disengage said pawl from said ratchet, a trip lever shaft rotatably mounted within said housing, a rocker secur-ed to said shaft, a trip lever rotatably mounted upon said shaft and having a free range of movement thereon beyond which said trip lever engages said rocker and moves said shaft, and a cam upon said shaft to engage said pawl to prevent movement thereof'independently of the movement of said pawl carriage.

HENRY D. BREEN.

Images