US1824150A - Brake for railroad switch machines - Google Patents

Description

Sept. 22, 1931. w. K. HOWE BRAKE FOR RAILROAD SWITCH MACHINES Filed Oct. 14, 1929 2 Sheets-Sheet 1 INVENTOR 1 Y 1a 7b? W. K. HOWE Sept. 22, 1931.

Filed Oct. 14, 1929 2 Sheets-Sheet 2 Y E N m T T A Patented Sept. 22, 1931 UNITED" STATES- PATENT OFFICE;

WIN'IHROP K. HOWE, 01E ROCHESTER; NEW YORK; ASSIGNOR T GENERAL RAILWAY SIGNAL'GOMPANY, 0F ROCHES'IER, ZN'EW' YORK BRAKE FOR RAILROAD .SW'ITGH .MACHINES Application filed October 14, 1929. Serial No. 399,549.

This-invention relates to devices used for the control of railroad track'switches, and more particularly pertains to a mechanical brake to be used with switch machines oper- 6 ating such switches.

'It is found in practice to be an essential factor of safety, that no movement of a track switch should be allowed except under authorized control. In some cases however, the 10 switch points are operated to the desired extreme position with the switch machine failing to lock the track switch, due to the opening of an over-load device. the failure of parts, or the like, which condition results 16 in the display of a stop indication by the governing signal. But the tower operator, or other official, desiring to facilitate the movement of traffic, orders the train to proceed'under flag, that is, send a flagman ahead 20 of the train which then proceeds over the apparently locked switch points.

Such a caseas pointed out above, is not so dangerous with the so called trailing point moves of trains, while the facing point moves produce a very undesirable hazard, in that the passage of the train produces a vibration and weaving of the track-rails which may open the switch points enough to engage a thin car wheel flangecausing a split train;

One object of the present invention is to provide means whereby such a contingency,

as pointed out above, shall be provided for by the use of a mechanical brake, which brake is eifective to prevent movement of the switch points at all times when the track switch is unlocked and its controlling switch machine motor is not supplied with authorized control power.

Other objects, purposes and characteristic 10 features will be in part obvious from the ac companying drawings and in part pointed out-as the description of the invention progresses. g g

In describing the invention in detail, ref- 4 erence will be made to the accompanying drawings, in which like reference characters indicate corresponding parts in the several views, and in which:

- Fig. 1 is a diagrammatic representation of 5 a motor of a switch machine and the switch machine controlling mechanisms for a track switch with the brake of the present invention shown interposed between the'switch machine motor and the mechanisms which are controlled thereby;

Fig. 2 is an end view of a mechanical brake shown as one specific embodiment of the present invention with parts shown in section astaken on the line 22 of Fig. 3

' Fig! 8 is a cross section of the mechanical brake of the'present invention taken on the line 3 -3 of Fig. 2.

WVit'h reference to Fig. l of the drawings, there is shown in a diagrammatic manner a track switch TS controlled by any suitable SWltCl11X1LCl1lI1,-SI10l1 as set-forth in my Paten-t 'No.- 1,466,903, dated September, 1923, with the brake B, as'the specific embodiment of thepresent inventiom'interposed between the motor 'M and the various mechanisms of the switch-machine. As the operation and construction of such a switch machine is completely disclosed in my above referred to patent, it is deemedunnecessary to describe the operationand construction of the switch machine, otherthan is necessary to explain the operation of the present invention.

The motor Mmay be controlled in any well knownmanner, for example, .as set forth in my Patent No.- l,550,611,: dated August 18, 1925, and is shown as controlled-over the normal and reverse control wires N and'R-in conjunction -with.a common wire 0 (see Fig. 1). The torque produced by the motor M during operation, is transmitted through the brake i B to the pinion 1 which meshes with a bevel gear 2. This bevel gear 2 is connected with a friction clutch. K, which in turn 'is con nected to the pinion 3, which pinion meshes with a gear 4. The gear 4 drives a pinion 5, whichin turn operates the main drive gear 6 'of the switchmachine. i a The initial movement of the main drive gear 6 in either a reverseor a normal direction, that is,:in a direction to control the track switch TS to a normal or to a reverse position respectively, controls the lock plunger LP through a considerable distance before a lock dog LD" disengages a throw-bar TB and before theilockvdog LD disengages the lock rods LE and LR, at which time the main drive gear 6 operates the throw-bar TB to an opposite extreme position. The movement of the throw-bar TB operates the track switch TS from an extreme normal position to an extreme reverse position, which movement also operates the lock rods LE and LE to reverse positions. With the throw bar TB and the lock rods LE and LE in reverse positions, the main drive gear 6 continues rotation, which moves the lock plunger LP to such a position that the lock dog Ll) again engages the throw bar TB and the lock dog LD again engages the lock rods LE and LE From the above description, it is obvious that the motor M can only operate the track switch TS at such times that the track switch is unlocked, and conversely, any force applied to the track switch can only tend to operate the switch machine mechanism at such times that the track switch is unlocked. Thus, the provision of the brake B which permits the motor M to operate the track switch TS and which prevents the track switch from operating the motor. accomplishes the desired result in that the track switch is prevented from movement at all times during which power is not ap lied to the switch machine motor.

With reference to Fig. 3. a rake drum ED is provided as integral with the motor frame 7. and is also suitabl ioined with a portion ot the switch machine frame 8. A motor shaft passes through. and is iournalled in the motor frame 7. This motor shaft 9 furnishes a bearing for the p n on 1 which meshes with the gear Two brake shoes 10 and 11 are secured to thepinion l b the pins 12 in such a m nner-tha two sp ings 13 and 1 evpapd he liralr hoe 10 and 11 until br ke l n n s 15 and 16 come into contact ith he lralrinq surface oi he h alze drum B11 The piv t o nts furn sh d h the ins ar in su h posi on that the .s-nrino' 13 tends t h s or for he brake shoe 11 a ainst the b ake drum BI). While th shrine- 14 tend to bias o for e hra e sho l0 a' ain t t e brake drum B ee Fin, ll. with su h an arrangement. toroue is applied o the in on 1.it cannot rotate due o the braking effect of th brake shoes 0 and 11. 7

To' accompl sh the compression of the springs 13 and Hand to allow the toroue applied to the shaft 9 tohetransmitted to the pinion 1, a drive member 17 is keyed to the shaft 9 by akev member 24 and is further secured by a pin 25 (see Fig. 3) .i This drive member 17 has'arms 17 and 17 which serve as'pivot points for links 18 and 19, attached to their respective arm supports by means of pins 20 and These links 18 and 19 are pivotally attached to the brake shoes 10 and 11 respectively at intermediate points between t-he pivot points 12 and the points at which the springs 13 and 14 apply expanding pressure to their respective brake shoes (see Fig. 2

When torque is applied to the shaft 9 by the motor M in either direction, forces are transmitted through the links 18 and 19 which are divided into component forces, so that certain compressing components tend to compress the springs 13 and 14:, and certain other rotational components tend to rotate the brake shoes 10 and 11 in a direction depending upon the direction of the torque provided by the motor M. It is further seen. when the compressing component forces are of sufiicient value to compress the springs 13 and 14, that the braking efi'ect is eliminated and the pinion 1 is caused to rotate with the brake shoes 10 and 11 in a direction in accordance therewith, thus controlling the track switch TS to a corresponding position.

The component forces causing the compression of the brake shoes 10 and 11 against the bias of the springs 13 and 14. continues to compress these brake shoes so that they come into contact with the arms 17 and 17 of the drive member 17. Such a position is maintained by the brake shoes 10 and 11 during the operation of the motor M, with the brake shoes expanding and assuming a braking position against the brake drum BD as soon as the motor ceases to receive power to drive the load.

Thus, when the track switch TS is unlocked, it is prevented from movement if the governing motor is not supplied with power, due to the brake of the present invention which is normally biased to a braking condition. However. it the governing motor is energized suiiicient to normally operate theswitch machine. the brake is first released and then continuously held in a released condition as long as an active driving torque is supplied to the switch machine. v

It is obvious that the mechanical brake of the present invention may be used with other types of switch machines than the specific type shown. Also, other applications of such a brake could be made, such as use with a car retarder mechanism or the like, or in other such cases where there is a driven element and a driving element.

Having described one specific embodiment of a mechanical brake constructed according to the present invention. it is to be understood that many alterations, modifications andv adaptations may be applied to the present invention to meet the requirements of practice without departing from the spirit or scope of the invention as set forth in the appended claims.

Having described my invention, I now claim 1. For use with a railroad track switch and a power driven switch machine, a mechanical brake including, a fixed brake drum, two brake shoes Within said fixed brake drum biased to engage said brake drum, means disengaging said brake shoes from said brake drum upon application of power to said switch machine including, a power driven shaft of said switch machine, a plurality of arms upon said power driven shaft, and means movably connecting said arms to said brake shoes, whereby rotation of said shaft in either direction in respect to said brake shoes disengages said brake shoes from said brake drum, and means operably causing said brake shoes to rotate with said shaft after said braking effect has been eliminated, including stops provided by said brake shoes and engaging said arms on said power driven shaft.

2. For use with a track switch for railroads and a power driven switch machine, a

mechanical brake including, a fixed brake drum, a pinion drive member, two brake shoes pivotally attached to said pinion drive member, two coil springs biasing said brake shoes to engage said fixed brake drum, a power driven. shaft, two drive arms on said power driven shaft, two links with each of said links pivotally attached respectively to one of said drive arms and pivotally attached to one of said brake shoes respectively, whereby said power driven shaft can operate said pinion drive member, and Whereby said pinion drive member cannot operate said power driven shaft.

3. For use with a track switch for railroads and a power driven switch machine, a mechanical brake including, a fixed brake drum, a pinion drive member, two brake shoes within said fixed brake drum having opposite extreme ends pivotally attached to said pinion drive member, two coil springs each of which bias one of said brake shoes to engage said brake drum, a power driven shaft, two drive arms extending for a prede tel-mined distance toward said brake shoes from said power driven shaft, two links each of which is pivotally attached to the one of said brake shoes opposite said drive arm, whereby said power driven shaft can compress said springs until said brake shoes come into contact with said drive arms, and whereby torque on said power driven shaft will operate said pinion drive member with a certain minimum value of load reaction present upon said pinion drive member, and whereby said pinion drive member cannot operate said power driven shaft.

In testimony whereof I affix my signature.

WINTHROP K. HOWE.

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