US2235031A - Railway switch operating apparatus - Google Patents

Description

March 18, 1941. K. J. J. McsowAN RAILWAY SWITCH OPERATING API'ARATUS Filed July 24, 1946 2 Sheets-Sheet 1 II 4m W w J j H 0 on c o I m 7 A h LM 0 occooo U C v m M @L in INVENTOR H15 ATTORNEY Patented Mar. 18, 1941 PATENT OFFICE RAILWAY SWITCH OPERATING APPARATUS Kenneth J. J. McGowan, Pittsburgh, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application July 24, 1940, Serial No. 347,269

4 Claims.

My invention relates to railway switch operating apparatus, and particularly to manually con.- trolled switch operating apparatus for spring switches.

More particularly, my present invention relates to railway switch operating apparatus of the type described and claimed in Letters Patent of the United States No. ,9 ranted to Herbert L. Bone on October 16, 1934. {In the said Bone apparatus, a switch is arranged to be moved between two spring biased extreme positions through the medium of a manually operated switch throwing mechanism including a reciprooable rack bar or motion plate, and to be looked a in one extreme position by means of a locking plunger biased to a locking position. The looking plunger is operatively connected with the rack bar in such manner that movement of the rack bar, in the direction to move the switch away from said one extreme position, will cause the locking plunger to be moved to its unlocking position prior to any movement of the switch points. The locking plunger is also operatively connected with linkage which, when the switch occupies its locked position and a train starts to trail the switch, is mechanically actuated by a train in a manner to move the locking plunger to its unlocking position before sufiicient force is exerted on the switch points by the train to overcome the force of the spring means which biases the switch points to said one extreme position.

One object of my present invention is to ima prove the construction of the locking mechanism and the means for operatively connecting it with the rack bar and the lock releasing linkage in apparatus of the type described in the said Bone patent.

Another object of my invention is to provide apparatus for looking a spring switch in one extreme position for facing point moves over the switch and for automatically unlocking the switch when a train trails the switch, which apparatus may be used in connection with the switch throwing mechanism described and claimed in Letters Patent of the United States No. 2,184,870, granted to- Herbert L. Bone and myself on December 26, 1939, 'for Railway switch operating mechanisms.

A further object of my invention is the provision in apparatus of the type described of improved means for biasing the locking plunger to its locking position, which improved means requires less spac-e, is cheaper to construct, and

exerts a stronger biasing force than the corresponding biasing means shown and described in the said Bone Patent No. 1,976,827.

According to my invention, a lock bar extends lengthwise of the switch throwing apparatus and cooperates at one end with a lock rod secured to the switch points to lock the switch in its one extreme position. The other end of the lock bar is pinned to a piston slidably mounted in a spring cage comprising part of a. biasing device for biasing the lock bar to its locking position. The spring cage, in turn, is slidably mounted in a cylindrical housing secured to one end of the apparatus casing and is operatively connected. at its inner end to the rack bar of the switch throwing mechanism by means of two spaced arms connected at their free ends by a depending web which extends into a transverse slot provided in the upper face of the rack bar. The piston of the biasing device is provided with a tubular extension having an annular inturned shoulder at one end, and this extension slidably receives the head of a plunger bolt comprising parts of the lock releasing linkage, to operatively connect the locking plunger with the lock releasing linkage.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

I shall describe one form of apparatus em- 3 bodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. l is a top plan view showing a spring switch A controlled 3 by a switch operating mechanism B constructed in accordance with my invention. Fig. 2 is an enlarged top plan View of the switch operating mechanism B shown in Fig. 1, with the main cover removed and a part of the casing broken away to better illustrate the construction of the various operating parts of the mechanism. Fig. 3 is a longitudinal sectional view of the mechanism shown in Fig. 2.

Similar reference characters refer to similar parts in all three views.

Referring first to Fig. 1, the reference character A designates a railway switch comprising, as usual, two fixed rails l and la and twp movable rails 2 and 2a. The fixed rails l and lo arel; laid on tie plates 3 and are secured to crossties 4 in the usual manner. The movable rails 2 and 2a are fastened together by a front rod 5, a head rod 6, a bridle rod '1 and a tie rod 8, and

may be moved into a normal or a reverse posi- 55 tion by means of a switch operating mechanism B which is connected with the head rod 6 through the medium of an operating rod 9 and a spring connecting rod C. When the switch occupies its normal position in which position it is shown in Fig. l, the movable rail 2 engages the fixed rail I, and the movable rail 2a is spaced a slight distance from the fixed rail I. When the switch is reversed, however, the movable rail 2a then engages the fixed rail Ia, and the movable rail 2 is spaced from the fixed rail The spring connecting rod C may be of any suitable type, but in the well-known form here illustrated, this connecting rod is similar in all respects to the spring connecting rod C shown and described in the Bone Patent No. 1,976,827 referred to hereinbefore. For purposes of the present disclosure, it is sufficient to point out that this connecting rod comprises a cylindrical housing Ii) which is secured to the head rod 6, and which slidably receives a spring rod M. The spring rod i4 is attached at one end to the operating rod 9, and is biased, by suitable spring means enclosed in the housing In, to an intermediate position relative to the housing in such manner that movement of the spring rod in either direction from this intermediate position will cause the spring means to become compressed and exert a yieldable force on the housing which tends to cause it, and hence the switch points, to follow the movement of the spring rod.

The head rod 6 is also connected by means of an adjustable link If with the piston rod I6 of a bufling device D. This bufiing device may also be i of any suitable type, but, as here shown, this buffing device is similar in all respects to the bufling device shown and described in Letters Patent of the United States No. 1,869,604, granted to William C. McWhirter on August 2, 1932, for Buliing devices for railway switches and the like. It is believed, therefore, that for purposes of the present disclosure the following brief description of the bufling device D will suflice. This buffing device includes, in addition to the piston rod l6, a cam shaft extending into the case of the device and controlling a valve mechanism not shown. Attached to the outer end of the cam shaft i1 is a crank 18 which is connected by ;a link IS with the spring rod l4 of the spring connecting rod C. If, when the movable rails 2 and 2a of the switch A are in their normal positions, as shown in Fig. 1, they are moved to their reverse positions by the mechanism B, the

piston rod IE will be moved into the device and the cam shaft will be rotated in a clockwise direction as viewed from the left in Fig. l. The construction of the device is such that, under these conditions, the piston rod IE will be permitted to move with substantially no resistance, and the bufiing device will therefore exert practically no retarding action on the movable rails. Conversely, if the movable rails are moved from their reverse positions to their normal positions by the mechanism B, the piston rod ||5 will be moved outwardly and the cam shaft i! will be rotated in a counterclockwise direction, as viewed from the left in Fig. 1, but due to the construction of the device, no retarding action will again take place. If, however, when the movable rails are in either extreme position, a train trails the switch, the cam shaft I! will remain stationary, and under these conditions, the action of the device is such that the movement of the movable rails away from the positions which they previously occupied will be unresisted by the buffing device, but that, when the movable rails are being restored to the positions which they previously occupied by the spring means of the spring connecting rod C, the buffing device will act to retard this latter movement.

The switch operating mechanism B is mounted on one end of a tie strap 20 which is secured to the ties adjacent the outer side of the rail and as best seen in Figs. 2 and 3, this mechanism in the form here shown comprises a suitable casing 2| which encloses the operating parts of the mechanism and which is closed at its upper end by a removable cover 22. in place at its right-hand end by means of a U- bolt 23 which overlies fingers 22a cast on the cover, and at its left-hand end by an adjustable hasp 24. This structure for securing the cover in place is described and claimed in the copending application for Letters Patent of the United States, Serial No. 287,116, filed by Herbert L. Bone and myself on July 28, 1939, for Cover securing means for casings.

Located within the casing I0 is a rack bar or motion plate 25 which is guided to slide longitudinally in a direction parallel to the track by means of guide rollers 26 and 21 secured to the underside of the rack bar adjacent its opposite ends and cooperating with a guideway 28 provided in the bottom wall of the casing. The rack bar 25 has rack teeth 29 formed on its upper surface on one side of the center line. These rack teeth mesh with a segment gear 30 mounted on a square shaft 3|, which shaft, in turn, is mounted at its ends in bearing sleeves 32 and 33 journaled in bosses 34 and 35 formed in the side walls of the casing Ill. Secured to the outer end of the shaft 3| by means of a through bolt 3'1 is a hand lever 38 which serves as a means for reciprocating the rack bar between its two extreme positions.

A roller 40 is secured to the underside of the .motion plate 25 adjacent one side thereof at a point equally spaced from the rollers 26 and 21, and this latter roller cooperates with cam faces 4| and 42 formed on an escapement crank 43 (see Fig. 2). The escapement crank 43 is formed integrally with the upper end of a switch actuating shaft 44, the shank of which is provided with two bearing surfaces 45 and 46 separated by an enlarged portion 41. The bearing surfaces 45 and 46 are journaled in vertically aligned bearings 48 and 49 formed respectively in the bottom wall of the casing 2|, and in a depending stirrup 50 which is provided on the underside of the casing, and adjustably secured to the enlarged portion 4'! of the shaft is a switch operating arm 50a. which is pivotally attached to the free end of the operating rod 9.

The portion of the switch operating mechanism thus far described is identical with that shown and described in United States Letters Patent No. 2,184,870 referred to hereinbefore.

A look bar 5| extends longitudinally of the casing 2| directly above the motion plate 25, and cooperates at its left-hand end, as viewed in Figs. 2 and 3, with a lock rod L which is slidably mounted in a transverse guideway 2 la formed in the casing 2|. The lock rod L, in the form here shown, is of standard construction, and is adjustably secured at one end to the front rod 5 of the switch A. Formed in the lock rod is a notch 48 so disposed that it will align with the lock bar 5| when and only when the switch A oc- The cover 22 is held cupies the extreme position. inwhich it is shown in Fig. 1.

The right-hand end of the lock bar as viewed in Fig. 3, extends with considerable clearance through an opening 52 formed in an. end plate 55 comprising part of a spring cage 54, and is pinned to a piston 55 reciprocably mounted within the spring cage. The spring cage is slidably mounted in a cylindrical housing 52 secured to one end of the casing Z l, and comprises, in addition to the end plate 53, a tube 55 which is partly closed at one end by the end plate, and a tube 51 of smaller diameter than the tube 55 screwed into the tube 55 at the end opposite to the end plate. The tube 57 is partly closed at its outer end by an end plate 55 brazed or otherwise secured to the tube, and this end plate is flattened on two sides for the reception of a suitable tool to facilitate screwing the tube 5! into the tube 55. A screw 59 is threaded into a tapped radial hole in the end plate 58, and has its head disposed in a slot 50 formed in the end of the tube iii to lock the two tubes inthe proper relative longitudinal positions. The spring cage houses a compressed coil spring 6!, one end of which abuts against the piston 55 and the other end of which abuts against the end plate 58. This spring is relatively stiff requiring considerable force to compress it, and the function of the inner tube 5? and associated end plate 55 is to provide a convenient means for compressing this spring during assembly of the parts. It will be apparent that the spring 6! serves to constantly bias the piston toward the position in which it engages the end plate 53. The spring 5.! is centered at the end which engages the piston by a tubular extension 63 formed on the piston, and the function of which will be made clear presently.

Formed on the end plate 55 of the spring cage 541 on opposite sides of the lock bar 5! are two spaced arms 55, the free ends of which are connected together by a depending web 55 disposed underneath the lock bar. This web extends into a transverse slot 6'! provided in the upper face of the rack bar 125, and serves as a means for operatively connecting the spring cage, and hence the lock bar 5!, with the rack bar for a purpose which will be made clear presently.

The parts are so proportioned that when the rack bar 25 is in its left-hand extreme position, as shown in Figs. 2 and 3, the biasing spring 6! will tend to drive the look bar 5! to an extreme position which is beyond the desired locking position. The locking device is prevented from moving beyond the desired locking position under these conditions, however, by linkage which connects the lock bar with the tie rod 8.

As here shown, this linkage includes a plunger bolt W provided with a round head I! which is slidably mounted in the previously described tubular extension 55 formed on the piston 55, and which. at times engages an annular inturned shoulder 53a formed on the right-hand end of the extension. The shank of the plunger bolt extends with clearance through an opening 53a provided in the end plate 58 of the spring cage 54, and through a bushing I? provided in the outer end of the housing 62, and is adjustably connected at its outer end by means of a turnbuckle it (see Fig. l) with one end of a link M, the opposite end of which link is pivotally connected With the long arm a of a bell crank lever 15. The bell crank lever 75 is pivotally supported in a crank stand it, and has. its short arm l5bpivfit otally connected with one end of an operating rod Ti. The other end of the operating rod 1'! is connected with the previously described tie rod 5 by means of a standard switch basket 18. The tie rod 3 may be located at any suitable location, but will preferably be located approximately half- Way between the heel and the point of the switch. The base 19 of the crank stand 16 is secured both to a gauge plate ill] and to the tie strap upon which the mechanism B is mounted, and it will be apparent, therefore, that any loss of adjustment between the parts due to creepage of the ties is prevented. The plunger bolt it, turnbuckle !3, link M, bell crank lever operating rod Tl, spring basket 18 and tie rod 8 all constitute means for effecting the unlocking of the switch during a trailing move, as will be made clear presently.

The lock bar 5!, adjacent the end which cooperates with the lock rod L, is slidably supported in a bracket 8!, which bracket also serves as a means for supporting a suitable circuit controller not shown. The contacts of this circuit controller are controlled jointly by the lock bar 5! and by a point detector rod 1?, and this circuit controller may, for example, be similar to that described and claimed in the previously referred to Letters Patent of the United States No. 2,134,870. The point detector rod P is slidably mounted in the casing 2!, and is attached by means of alink 82 and a bolt member 55 with the movable rail 2 of the switch A in the usual and well-known manner.

The operation, as a whole, of the apparatus is as follows: When the hand throw lever is rotated to its normal extreme position in which'it is shown in the drawings, the rack bar 25 is moved to its extreme left-hand or normal position in which it is shown in Figs. 2 and 3, and under these conditions the escape-merit crank 13 is held in its clockwise extreme position as viewed. in Fig. 2 by engagement of the roller 55 with the cam surface 4! of the escapement crank. When the crank 43 occupies this extreme position, a force is exerted on the movable rails 2 and Zia of the switch through the medium of the spring connecting rod C, which force yieldably holds the movable rails in their normal extreme positions in which they are shown in Fig, 1. When the movable rails are in their normal positions, the notch 48 in the lock rod L aligns with the lock bar 5!, and the lock bar is therefore moved. by the biasing spring 55 to its locking position in which the lock bar enters the notch it, thus securely locking the switch points in their normal positions.

When it is desired to reverse the switch, the hand-thrown lever 38 is rotated from the extreme position in which is is shown in Fig, 1 to its opposite extreme position. This movement of the lever causes the rack bar 125 to move from its extreme left-hand position, as viewed in Figs. 2 and 3, to its extreme right-hand position. This movement of the rack bar, in turn, is transmitted through the slot til, web 55, arms 85 and end plate 53 to the spring cage 55 which causes end plate 53 to move into engagement with the piston 55 as soon as the rack bar has moved a short distance. As a result, as the rack bar continues to move, the lock bar 5! is moved with the rack bar, thus withdrawing it from engagement with the notch t8 in the lock rod L, and hence unlocking the movable rails 2 and The parts are so proportioned that While the lock bar is being withdrawn from engagement with the notch 48 in the lock rod, the roller 40 on the rack bar will continue to engage the escapement crank 43 at the cam face 4| which during this movement is parallel to the direction of movement of the rack bar, and as long as this portion of the cam face is engaging the roller, the crank 43 will remain stationary. It follows, therefore, that during that portion of the movement of the rack bar which is necessary to unlock the movable rails of the switch, no force is exerted on these rails tending to reverse them. As soon, however, as this first part of the movement of the motion plate has been completed, the roller 40 then moves into engagement with the cam face 42 of the escapement crank which causes the crank to be rotated in a counterclockwise direction, as viewed in Fig. 2, and as a result the rails are then moved to their reverse positions. As previously pointed out, when the rails are being moved to their reverse positions by the mechanism B, the piston rod l5 of the buffing device B is moved into the device, and the cam shaft I! is rotated in a clockwise direction, as viewed from the left in Fig. 1, but due to the construction of this device, the device oifers substantially no resistance to the movement of the rails under these conditions. It should be noted that as long as the movable rails remain stationary, the plunger bolt 10 remains fixed, so that during the first part of the movement of the motion plate, the shoulder 63a will move out of engagement with the head H of the plunger bolt. As soon as the movable rails have started to move, however, the resultant movement of the tie rod 8 acting through the switch basket 78, operating rod 'i'l, bell crank lever 15 and link 14 causes the plunger bolt to move in the same direction as the rack bar is moving, although the time of motion and rate of motion of the plunger bolt will bear no direct relation to the movement of the rack bar. During the final movement of the rack bar, the roller ll! moves along the straight portion of the cam surface 42 to such a position that any tendency of the switch actuating shaft to rotate in a direction to permit the switch points to move away from their reverse positions is effectively blocked by the roller. It will be seen, therefore, that when the switch points occupy their reverse extreme positions, they are effectively held in these positions due to the coaction between the roller and the escapement crank, and it will also be seen that any force which may be exerted on the switch tending to restore it to its normal position will cause a transverse force to be exerted on the rack bar rather than a longitudinal force, thus avoiding any tendency to reverse the handthrow lever due to any force which may be exerted on the switch.

In order to restore the movable rails to their normal positions after they have been reversed as above described, the hand-throw lever 38 is restored to the position in which it is shown in Fig. 1. The subsequent movements of the parts under these conditions are just the reverse of those described above, and it is believed, therefore, that the operation of the apparatus under these conditions will be readily understood from an inspection of the drawings without further description.

I shall now assume that the parts are in their normal positions, as shown in the drawings, and that a train trails the switch. As the leading wheels of the train r011 along the fixed rail I and the movable rail 2a, the movable rails 2 and 2a are forced over laterally, but before a sufficient force is developed to overcome the opposing force of the spring connecting rod C and cause the point of the movable rail 2 to move out of engagement with fixed rail l, the movable rails being somewhat resilient become bent, so that with the usual standard split switch, the tie rod 8 is moved upwardly, as viewed in Fig, 1, three quarters of an inch or more. This movement of the tie rod 8 acting through the switch basket 18, operating rod Tl, bell crank lever 75, link 14, turnbuckle T3 and plunger bolt Ill moves the piston 55 of the spring cage 54, and hence the lock bar 5|, in opposition to the bias of the spring 8| a suflicient amount to withdraw the lock bar 5| completely out of engagement with the notch 48 in the lock rod L, thus unlocking the switch. As a result, when the leading wheels have reached the positions in which a suflicient force is developed to cause the point of the movable rail 2 to move out of engagement with the fixed rail I, the switch points will be unlocked, and the points will therefore be forced open by the wheels in exactly the same manner as would be the case if no point lock were provided, and the buning device D will perform its usual function of preventing the movable rails from snapping back after the passage of each wheel through them. When the train which is trailing the switch has completely passed the switch, the movable rails will slowly return to their normal positions under the bias of the spring connecting rod, and against the retarding force of the buffing device D. Dur ing this return movement of the movable rails there will be no deflection of these rails, and the lock bar El will be moved into engagement with the side of the lock rod L before the movable rails have reached their full normal positions in which the lock rod. is in the proper position for the notch 48 therein to receive the locking plunger. The spring 6! will therefore become compressed, and will urge the lock bar 5| into engagement with the side of the lock rod, until the notch 48 moves into alignment with the lock bar, at which time the energy stored in the compressed spring 6i will force the lock bar into place in the notch 48, thus restoring the switch to its normal locked condition. If the notch 48 in the lock rod should not come into alignment with the lock bar, a suitable indication of this fact will be given by means of the circuit controller referred to hereinbefore.

During a facing point move, there is no lateral thrust on the movable rails corresponding to, or commensurate with, that which occurs during a trailing movement, and what lateral thrust there is will be in the direction to permit the spring 6| to force the locking plunger further into the notch 48 in the lock rod L.

It will be noted that when the parts are in their normal positions, as shown in Fig. 1, the reaction of the biasing spring BI is transmitted through the rack bar and segment gear 30 .to the hand-throw lever 38, which tends to raise this lever. However, this lever is so designed that it has sufiicient weight to resist and overcome this reaction. Furthermore, if it is undesirable to provide the lever l3 with sufficient weight 'to overcome the reaction of the spring 6|, this lever may be held down by means of a conventional gravity lever latch stand, two of which stands are indicated at 9! in Fig. 1.

One advantage of switch operating apparatus embodying my invention is that the construction of all of the parts are relatively simple and are such that they can readily be assembled and disassembled in service.

Although I have herein shown and described only one form of railway switch operating apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. The combination with a spring switch and a switch operating mechanism comprising a casing containing a rack bar reciprocable between two extreme positions and operatively connected with the switch for moving the switch between its two extreme positions, of a lock bar slidably mounted in said casing above said rack bar and movable between a locking position in which it looks said switch in one extreme position and an unlocking position, a spring cage slidably mounted in said casing and operatively connected at one end with said rack bar for movement therewith and provided in one end with an opening through which said lock bar extends into said spring cage with clearance, a piston in said spring cage secured to said lock bar, and a spring in said Spring cage engaging said piston and effective when said rack bar occupies the position corresponding to said one extreme position of said switch to bias said lock bar to its locking position.

2. The combination with a spring switch and a switch operating mechanism comprising a casing containing a rack bar reciprocable between two extreme positions and operatively connected with the switch for moving the switch between its two extreme positions, of a tubular housing secured to one end of said casing, a tubular spring cage slidably mounted in said housing and containing a reciprocable piston biased toward one end of said spring cage, means for securing said spring cage to said rack bar to move therewith comprising spaced arms provided on said one end of said cage and connected together by a depending web disposed in a transverse slot provided in said motion plate, a lock bar reciprocably mounted in said casing above said rack bar and extending at one end into said cage between said arms with clearance and secured to said piston, and means cooperating with said lock bar for locking said switch when said switch occupies said one extreme position and said piston occupics the position to which it is biased by said spring.

3. The combination with a spring switch and a switch operating mechanism comprising a casing containing a rack bar reciprocable between two extreme positions and operatively connected with the switch for moving the switch between its two extreme positions, of a lock rod connected with the movable rails for movement therewith and provided with a notch, a lock bar adapted to enter the notch in said lock rod when and only when the switch occupies its normal position to lock the movable rails in this position of the switch, said lock bar being movable within said notch to an extreme position which is beyond the normal locking position, a housing secured to one end of said casing, a spring cage slidably mounted in said housing and operatively connected at one end with said rack bar to move therewith, a piston in said spring cage operatively connected with said lock bar, a spring in said spring cage engaging said piston for biasing said lock bar to said extreme position when said motion plate occupies the extreme position corresponding to said one extreme position of said switch, a tubular extension on said piston provided at its free end with an annular inturned shoulder, a plunger bolt extending into said tubular extension through clearance holes in said housing and said spring cage and provided with a head cooperating with said shoulder, and linkage adapted to be mechanically actuated by a train trailing said switch connected with said plunger bolt, said linkage being so constructed and so adjusted that when said switch occupies its normal position said linkage will act through said plunger bolt, said shoulder, said tubular extension and said piston. to prevent said locking plunger from moving beyond its normal locking position but that when a train trails the switch said linkage will act to withdraw said locking plunger from the notch in said lock rod to unlock the switch.

4. The combination with a spring switch and a switch operating mechanism comprising a casing containing a rack bar reciprocable between two extreme positions and operatively connected with the switch for moving the switch between its two extreme positions, of a lock bar slidably mounted in said casing and movable between a locking position in which it locks said switch in one extreme position and an unlocking position, a spring cage slidably mounted in said casing and operatively connected at one end with said rack bar for movement therewith, and spring means in said spring cage operatively connected with said lock bar and effective when said rack bar occupies the position corresponding to said one extreme position of said switch to bias said lock bar to its locking position.

KENNETH J. J MCGOWAN.

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