US2341718A - Switch machine for railway spring switches - Google Patents

Description

Feb. 15, 1944. w. K. HQWE I 2,341,713

SWITCH MACHIYI-JE FOR RA LWAY SPRING sw ITcHEs Filed Nov. 20, 1940 iNVENTOR I leaf L2,

ATTORNEY Patented Feb. 15, 1944 SWITCH MACHINE FOR RAILWAY SPRING SWITCHES Winthrop K. Howe, Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Application November 20, 1940, ,Serial No. 366,399

Claims.

This invention relates in general to switch machines for railway switches, and has more particular reference to machines for spring switches which are lockable in normal position and-can be hand operated to either normal or reverse position, and are trailableby-cars to either position.

The machine forming the subject matter of the present invention, which can be operateclby hand to either position, is, when operated from normal to reverse position, first unlocked, and then thrown, and when operated from reverse to normal, first thrown and then locked.

The throw-rod for the track switch includes a spring bufier, which biases the switch to the .position at which it is set, and permits trailing of the switch by compression of the spring of the butter. The back-slap tendency of the switch, under the influence of the compressed spring, .between the passages ofsuccessive car wheels,.is prevented by a buffer or dash-pot mechanism in the spring buffer.

When the switch is trailed from normal it is of course necessary to first unlock it before the switch pointscan be ,moved, and this is accomplished by means .of a track treadle operated by the trailing car somewhat prior to itsreaching the switch points.

The various parts areso arrangedthat theunlocking treadle, which is .biased to its normal position by resilient means, is prevtned from slapping back .to its normal position between passages of successive car wheels,.by .the samedashpot mechanism that is employed .for preventing the back slap of thespringswitch.

Since .a portion of the movement of a .usual hand switch stand handle is used for switch unlocking, a gain-stroke device is employed to mu1- tiply. movement on hand throwing the switch so that the usual arc of movement of the hand switchstand handle is suflicient to not only 11nlock the switch but to move it to extreme position.

The machine of this invention can be employed for switches facing either right or left hand, by partlyrotating the machine, .and then reversing certain of the operatingparts, as will appear below.

One form of .the invention .is shown in the accompanying .drawing, which is wholly diagrammaticin form, issolely ,for the purpose of illustration,;and.is not employed in .any way whatsoeverin 'a limiting sense. In the drawing- Fig. 1 is .a wholly schematic view of one .form of this invention.

Fig. 2 is 1a detailed1view toan enlarged scale,

of a spring buffer constituting part of this invention.

Referring now to the drawing, and first to Fig. 1, there is here shown astretch of main track constituted by track rails I, with a track switch 'I'Sleacling from .the main track to a passing sidmg.

A track treadle Tr is positioned. adjacent one of the rails of the track switch so as to be operated by the wheels of a car passing from the siding and onto the main track, just prior to the wheels reaching the switch points. This treadle is shown in a wholly diagrammatic manner, as constituted by a bar 2 pivoted to support legs 3, and depressable by a car wheel on the adjacent switch rail, so as to ,movean operating lever d downwardly as viewed in the drawing. The lever 4 on moving downwardly compresses a spring 5 normally biasing the'treadle to its raised normal position, to thereby operate a crank 6 pivoted at '6 and exert .a pull to theleft on an unlocking rod 1 which .pivotally carries ,a pinion 8.

The track switch is connected to a usual lock rod LR-which has a notch 9 for receiving a lock plunger Ill. The lock plunger it is connected to a rack ll, slidable in a support l2, and meshing with the pinion 8. A rack 13, slidable in a support l4, also meshes with pinion 8, on the side opposite to rack ll, and carries a pin 15 engaged in a slot [6 in one endof a leverll, pivoted at its other end as at 1.8 to. a fixed pivot in the machine.

Lever ll, intermediate its ends, carries an operating pin l9, received in'a cam slot in an operated member OM. Thisslot has an inclined portion 20 which ;can be considered an unlocking portion, and a vertical portion 2| whichis a lost motion portion.

The operating member OM carries a second cam slot having a lost motion switch locking vertical portion 22, and a curved generally horizontal portion 23, which can be considered a switch operating portion.

In this second slot is a pin'2 l carried at one end by one end of an operating plate 25, pivoted at its other end to a fixed pivot pin 26. This plate 25 carries two pins 21 and 28, which are received respectively in an intermediate hole in a second operating plate 29 which is pivoted. on thepin 26 and inan edge groove 30 therein, there being an opposed edge groove 3| in the plate, the

. function of which will appear below.

Plate 29 atitsend opposite its fixed pivot 26, carries -a;pin -32 receivable in a horizontal slot 33 in the machine throw-rod TR. This throw-rod, at its other end, is connected to a rod 34 entering the spring buffer SB while the casing connection portion 44 on the casing of the spring buffer is connected to the track switch points by a rod 35.

A detector rod DR for the track switch is shown as connecting the track switch with the switch machine which latter is indicated by the rectangle SM. This detector rod, however, is not involved in the present invention.

The switch machine has a usual hand-throw rod HT which carries the operating member OM referred to above, and is connected at its lower end to a usual hand switch stand HS. .Asviewed in Fig. 1, this connection includes a reciprocating operating rod 31, which is slotted to receive a cam 38 on a rotatable member 39 which can be rotated substantially 180 by the handthrow operating handle 46. The handle 46 can be moved from its shown position to a position opposite thereto, and any usual latch or lock means can be employed for holding the handle in its thrown position. This handle is also furnished with a usual weight 4| for biasing it to its thrown position. Furthermore, the slope of the cam 38 is such that a backward drive from the switch to the handle is prevented.

As stated above, the drawing is wholly schematic and no attempt has been made to show any actual construction, or actual sizes or proportions. Before describing the operation of the machine, as described above, it might be best to consider the details of construction of the spring bufier SB.

Referring to Fig. 2, the spring buffer is shown as having a casing 43 with two ends 44 and 45 bolted thereto, the end 44 being connected by rod 35 to the track switch and the end 45 having an opening for slidably receiving the rod 34 to which the throw-rod of the machine is connected. Rod 34, slidable in the casing, is packed liquid tight by packing 46. An opening 41 is provided for filling the casing with oil, or other suitable liquid, and is normally closed by a plug 48.

Within the casing is a partition 49 dividing the casing into a reservoir 50, and a piston chamber connected to the reservoir by an opening Kil The piston chamber contains, at one end, a piston 53, and at the other end a piston 54 with a spring 55 trapped between the two pistons and comprised so as to force them away from each other. The pistons are tied together by heads 56 and 51 on the rod 34 whereby each piston can be moved inwardly on the rod 34 toward the other piston and against the spring tension but cannot be moved outwardly away from each other.

The piston 53 is furnished with a check valve 58 urged by a spring 59 to close ports 60 in the piston, the spring 59 being trapped between the valve 58 and a head 6| fixed to the piston. Valve 58 has a bleed passage 62 therein for a purpose to be described below.

The other piston 54 is equipped identically with the one just described with reference to its valve 63, spring 64, holding head 65, and bleed port 66.

The partition 49 at each end has an inner longitudinal groove 6'! and 68 to form a relatively large bi-pass around the piston. This groove extends only a-short distance inwardly from each closed, the only communication past the piston is through its bleed port.

As shown in Fig. 1, rod 35, connecting the buffer with the track switch carries a stop lug 69 against which a treadle holding rod 10, pivoted at H to a fixed point, and connected at T2 to a rod 73 normally bears, as shown.

The machine, as described above, permits operation of the spring switch by hand to either extreme position in which the spring buifer resiliently holding the switch against movement away from its thrown position so permitting trailing thereof. In the event the switch be trailed from its normal to its reverse position, the spring buffer is brought into operation and returns the switch points to their original position after the train has passed, and during the passage of successive wheels exerts a dashpot or retarding effect to prevent the switch points from slapping against the rails. In this case, the first wheel of the car first passes over the treadle to unlock the track switch, and the spring 5 which returns the treadle to normal position is prevented from slapping the treadle against the car wheels as successive wheels pass over it, by the same spring buffer that prevents slapping of the switch points between successive car wheel passages.

Consider now the operation of the machine in some detail. An east bound train passing from the siding and onto the main track depresses the treadle just before it reaches the switch points to thereby compress spring 5 and move rod 1 to the left, as viewed in the drawing. Since rack I3 is held stationary by the hand operated switch stand, pinion 8 rolls on rack 13 and moves rack I l to the left at twice the speed of rod 1 to draw lock bolt l0 out of engagement with lock rod LR to thereby unlock the switch.

Immediately thereafter, the car wheels force the switch points to their reverse position. In doing this, rod 35, connected to the casing of the spring buffer SB, is moved in a direction toward the track to thereby compress the buffer spring while the pressure of fluid between the pistons opens check valve 58 and allows the fluid to freely pass beyond the check valve and fill the space opened up between head 44 and the outer face of the piston. Thus the switch is quickly. moved against the pressure of spring 55 while the fluid can freely pass from one side of the piston to the other.

When the switch is released from the pressure of a pair of car wheels, the spring of the buifer tends to return it, and likewise, the spring 5 tends to return the treadle. However, when the treadle was depressed, arm 16 moved towardthe track and away from stop lug 69, and when the switch was trailed, the stoplug 69 was moved up against arm 10 in its treadle depressed position. Accordingly, the spring bufier acts to prevent not only the switch points from slapping against the rails, but also the treadle from moving back to its normal position and slappingagainst the wheels. This buffing actionv is producedhy the, liquid which has passed beyond the valve 58, and which on attempting to return to the central part of the spring chamber is largelyprevented from I doing so by the check valve since the piston has passed beyond the side port 67 and has a tight fit in the chamber. The bleed port allows so little liquid flow that practically no return'movement of the switch or treadle is permitted.

Upon the train clearing the switch the switch points return to normal position by slowmov'ement at first, due to fluid passing through the bleed port 62, and after the piston has passed opposite the large port 61 and the fluid can pass more freely by a relatively fast movement to the normal position. At the same time, the treadle is allowed to return to normal position, due to lug 69 moving out of the way of arm 10 and the switch is locked up by means of pinion 8 operating rack II and with it look bolt l0.

With the track switch in its reverse position, it is unlocked, and a train, on trailing it to normal position, moves the spring bufier casing away from the track rails to open check valve 63, compress spring 55, .and produce a bllfi'ing action at this valve.(63) end, in the same manner as described above.

"Thus, the spring bufier not only resiliently holds the track switch against movement away from its thrown position, but, uponbeing trailed, it prevents not only the switch, but also the treadle, respectively, from slapping against the rails and car wheels, as the wheels pass.

The treadle is shown in a purely conventional manner as a depressable treadle inclined in the direction of the travel of the car; This treadle, however, can be of any other usual type so long as the passage of a car causes the movement of arm 1 and pinion 8. The treadle is positioned with respect to the switch points so that it is in depressed position due to a wheel operating it at the time forward car wheels are in positionto'move the switch points. I

Considering now the operation of thetrack switch by the hand switch stand, letgus assume that it is desired to move the switch by hand to its reverse position. Lever 48 of the switch stand is moved to its reverse position, thereby causing cam 38 to move hand throw rod HT and with it operating member OM forward toward the track.

During the first part of the movement of member OM pin 19 is moved to the right due to the inclined portion 26 of the cam slot, thereby swinging lever i1 clockwise so as ,to move rack l3 to the right, and through the pinion 8 move rack H to the left so as to unlock the track switch. After the switch is unlocked, pin I9 is held against further sidewise movement by means of the vertical portion H of the cam slot.

By the time unlocking has taken place, pin 24 has passed through the vertical slot portion 22 and is received in the horizontal slot portion 23. Continued movement of the handthrow rod turns plate 25 clockwise on its pivot :pin 26 to thereby turn plate 29 clockwise through the connecting pins 21 and 28. This turning of the plate 29 causes pin 32 to move the switch-throw rod TR in a direction toward the track switch to thereby throw the track switch to its reverse position and at the same time through lug 69 and rod 1'0 to depress the treadle. The treadle spring 5 is relatively weak and requires perhaps 50 pounds pressure to operate it and hence no very large extra load is imposed on the hand switch stand operation.

n moving the switch from its reverse to its normalposition, the hand switch stand lever 46 is returned to its shown position, and the operations, as above described, take place in reverse order, That is, the switch is first thrown, and then is locked up.

During the hand operation of the switch, the spring buiier moves as. a unit, and the buffer spring 55, which is a very strong spring is not compressed.

is received in the other side groove 3!.

In the usual hand switch stand, a movement of the hand lever through 180 completely throws the switch from one extreme position to the other. When the first portion of the lever movement is employed in unlocking the switch, the remaining portion of the movement is insufficient to cause the complete movement of the switch points unless there be a multiplying effeet, or gain-stroke mechanism, as constituted by the pivoted operating plates 25 and 29.

In case it is desired to use the machine in connection with a left hand track switch as one at the other end of the passing siding, it is so constituted that this can readily be done. All that is necessary is to rotate the machine 180 to bring the lower end of the machine in position to face the track switch. Then the hand-throw rod must be turned endfor end in the machine and "turned over so that the bottom of operating member OM is on top. Furthermore, the operating plate 25 must be shifted with respect to the operating plate 29 so that pin 28 is received in the hole in the center of plate 29, and pin 2'! With these simple changes, the machine can be readily connected to the track switch and the hand switch stand, the. treadle and the bufier, and will operate in the manner described above.

The above rather specific description of one form of this invention has been givensolely by way of example, and is not intended in any manner whatsoever in a limiting sense. It is to be understood that various modifications, adaptations and alterations can be applied to meet the requirements of practice, without in any manner departing from the spirit or scope of the invention except as limited by the appended claims.

What I claim is:

1. In spring track switch operating means, in combination, a track switch movable to normal and reverse positions, elastic means resisting movement due to a trailing car move of the switch from either of said-positions, means look-- ing the switch in at least one of said positions, a car-operated track device connected to the locking means, means to bias the track device to inoperative position, the device being positioned to be moved by a switch trailing car to its operative switch unlocking position, a retarding means, and means operatively connecting both the switch and the track device to the retarding means so as to retard movement of the switch from intermediate positions and movement of the track device from its operative position.

' 2. In track switch operating means, in combination, a track switch movable to normal and reverse positions, locking means to lock the switch in one of said positions, switch operating means for operating and locking, and for unlocking and operating, the switch, a spring buffer operatively interconnecting the operating means and the switch, resilient means in the buffer resisting movement of the switch from either normal or reverse position due to force acting directly on the switch, automatic car actuated lock operating trackway means adjacent the switch and normally positioned to be moved to reverse, unlockin position by a car approaching the switch to trail the switch from the track rail against which the switch is set in its locked position, resilient means biasing the automatic lock operating means to said normal locking position, bufiing means in the bufier for retarding the speed of return of the switch to either normal or reverse positions after being trailed through,

and means connecting the automatic operating means to the buifing means so that the buiTer retards the speed of return of the lock operating means to normal position from its reverse position.

3. In track switch operating means, in combination, a track switch movable to normal and reverse positions, locking means to lock the switch in one of said positions, switch operating means for operating and locking, and for unlocking and operating, the switch, a spring buffer operatively inter-connecting the operating means and the switch, resilient means in the bufier resisting movement of the switch from either normal or reverse position due to force acting directly on the switch, automatic car actuated lock operating trackway means adjacent the switch and normally positioned to be moved to reverse, unlocking position by a car approaching the switch to trail the switch from the track rail against which the switch is set in its locked position, resilient means biasing the automatic lock operating means to said nonnal locking position, buffing means in the buffer for retarding the speed of return of the switch to either normal or reverse positions after being trailed through, and means connecting the automatic lock operating means to the buffing means so that the buffer retards the speed of return of the lock operating means to normal positio from its reverse position.

4. In track switch operating means, in combination, a track switch movable to normal and reverse positions, locking means to lock the switch in one of said positions, a switch throw rod, switch operating means including the throw rod, for locking, unlocking, and operating the switch, said switch operating means including means to hold the throw rod against movement during the unlocking period, a spring bufier operatively inter-connecting the throw rod and the switch, resilient means in the buffer resisting movement of the switch from either normal or reverse position due to force acting directly on the switch, automatic car actuated lock operatq ing trackway means adjacent theswitch and normally positioned to bev moved to reverse,=unlocking position by a car so approaching the switch as to trail the switch from the track rail against which the switch isset in its locked position, re-r silient means biasing the automatic lock operating means to said normal locking position, bufiing means in the bufier for retarding the speed of return of the switch to either normal or reverse positions after being trailed through, and means connecting the automatic lock operating means to the butting means so that the bufier retards the speed of return of the lock operating means to normal position from its reverse position.-

5. In track switch operating means, in combination, a track switch movable to normal and reverse positions, locking means'including alock rod and a lock bolt for locking the switchinnormal position, a switch throw rod, switch operating means including the throw rod, for locking, unlocking, and operating the switch, a spring bufier operatively inter-connecting the throw rod and the switch, resilient means in the bufier resisting movement of the switch from either normal or reverse position due to force acting on the switch other than through the switch operating means, automatic car actuated lock operating trackway means adjacent the switch and-positioned to be moved to reverse, unlocking position by car approaching the switch so as to trail the switch from the track rail against which it is set in its locked position, resilient means biasing the lock operating means to the normal locking position, buifing means in the buffer for retarding the speed of return of the switch to either normal or reverse after being trailed through, means connecting the automatic lock operatin means to the bufiing means so as to retard the speed of return of the lock operating means to normal position from its reverse position, saidswitch operating means including means to hold the throw rod against movement during the unlocking period, and means to hold the lock bolt stationary during the switch throwing period.

WINTHROP K. HOWE.

Images