US2380145A - Railway switch operating apparatus - Google Patents

Description

July 10, 1945. BONE 2,380,145

RAILWAY SWITCH OPERATING APPARATUS Filed Feb. 12, 1944 17 "ii *3, 19 -Y-'"r l B A x INVENTOR Afevaere I. 59129. a m

H11 ATTORNEY Patented July 10, 1945 RAILWAY SWITCH OPERATING APPARATUS Herbert L. Bone, Forest Hills, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application February 12, 1944, Serial No. 522,098

. 7 Claims.

My invention relates to railway switch operating apparatus, and particularly to switch operating apparatus for switches of the so-called spring return type in which the switch points set in a given position relative to the main rails of the track are adapted to yield laterally against the action of spring return means in the passage of a trailing train and to be retarded in the return movement to the normal set position under the action of, the Spring return means by dash-pot or buffer mechanism.

More particularly, my present invention relates to railway switch operating apparatus in which the spring return means and buffer mechanism are combined into a unitary structure similar to that described and claimed in Letters Pat- -ent of the United States No. 2,191,246, granted to O. W. Andersen on February 20, 1940, for Railway switch piston and cylinder device.

In switch operating apparatus of the typedescribed, there is a sudden reversal in the direction of loading on the biasing and buffing device following the passage of each wheel or truck on a car trailing the switch, and this sudden reversal causes a sudden shock to be transmitted through reversal in the direction of .the loading on the biasing and bufilng device is prevented from reaching the working parts of the switch operating mechanism.

According to my present invention, I accomplish the above outlined object by employing between the crank of the switch operating mechanism and the biasing and buffing device a modified form of screw jaw having an adjustable stop that cooperate with the casing of the switch operating mechanism or its equivalent so that the shock of the sudden reversal of the parts will be absorbed by the casing rather than by the working parts of the mechanism. The provision on the screw jaw of the stop also reduces wear on the switch points because of the resulting reduction in the amount of motion which can take place when the loading on the buffing device becomes reversed.

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

I shall describe one form of railway switch operating apparatus embodying my invention,

and shall then point out the novelfeature thereof in claims.

In the accompanying drawing, Fig. 1 is a top plan view showing a spring switch controlled by a switch operating mechanism constructed in accordance with my invention. Figs. 2 and 3 are enlarged top plan and end views, respectively, of aportion of the .mechanism shown in Fig. 1.

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 two movable rails or switch points 2 and 2a.. The fixed rail I and la are 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 position by means of a switch operating mechanism B which is connected with the head rod 6 through the medium of a screw jaw 9 and a combined biasing and buffing device D. When the switch occupies its normal position in which position it is shown in Fig. 1, the movable rail 2 engages the fixed rail I, and the movable rail 2a is spaced a slight distance from the fixed rail la. When the switch is reversed, however, the movable rail 2a then engages the fixed rail la, and the movable rail 2 is spaced from the fixed rail I.

The combined biasing and buiiing device D is similar in all respects to that described in Letters Patent of the United States No. 2,191,246 referred to hereinbefore, and it is believed, therefore, that for purposes of the presentdisclosure it is suflicient to point out that this device comprises a cylindrical housing I 0 which is secured at one end to the head rod 6 and the other end of which slidably receives an operating rod 1 l. The operating rod l l is adjustably secured at its free end to the screw jaw 9, and is biased by suitable spring means enclosed within the housing II], to an intermediate position relative to the housing in such manner that movement of the operating rod in either direction from its 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 movements of the operating rod. The operating rod is also connected within the housing I0 with double acting bufiing means which becomes efiective upon movement of the operating rod by the spring means to limit the rate of movement of the operating rod to a predetermined controlled rate which is sufliciently slow to prevent slapping of the switch points between the passage of successive wheels or trucks of a car or train trailing the switch. The switch operating mechanism B may be of any suitable type, but as here shown this mechanism is similar to that described and claimed in Letters Patent of the United States No.

2,235,031, granted to Kenneth J. J. McGowan on March 18, 1941, for Railway switch operating apparatus. For purposes of my present application it is suflicient to point out that this mechanism comprises a suitable casing l2 containing a switch actuating shaft l3 provided at its lower" end with a switch operating crank I 4 pivotally the switch actuating shaft l3 in such manner that rotation of the hand throw lever between its two extreme positions will rotate the switch actuating shaft between corresponding extreme positions. The mechanism further comprises a locking plunger which is biased to a locking position and which cooperates in its locking position with a lock rod L secured to the front rod 5 of the switch A to lock the switch in the extreme position shown. The locking plunger is operatively connected with the hand throw lever l5 through the medium of the previously mentioned motion plate in such manner that when the hand throw lever is moved in the direction to move the switch away from its normal extreme position, the locking plunger will be moved to an unlocking position in which it is disengaged from the lock rod L prior to any movement of the switch points. The locking plunger is also operatively connected with linkage I6 connected to the tie 1nd 8, which linkage when the switch occupies its locked position and a train starts to trail the switch, is mechanically actuated through the medium of the tie rod 8 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 biasing force of the device D which biases the switch points to the set position shown.

.It will be seen, therefore, that with the apparatus constructed in the manner thus far described the device D will act to bias the switch points to a set position corresponding to the extreme position to which the hand throw lever l5 of the mechanism B is moved, and that when the hand throw lever l5 occupies the extreme position shown the switch points will be securely locked in these positions by the coaction of the locking plunger with the lock rod L. When a train trails the switch, as the leading wheels of the train roll along the fixed rail I and the movable rail 2a, the movable rails 2 and 211 will be forced over laterally, but before a suflicient force is developed to overcome the opposing force exerted by the device D and cause the point of the movable rail 2 to move out of engagement with the fixed rail, the movable rails being somewhat resilient will become bent, so that, with a standard split switch sufiicient lateral movement of the rails will take place to cause the linkage IE to move the locking plunger to its unlocking position. 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 in opposition to the biasing force exerted by the device D in exactly the same manner as would be the case if no point lock were provided, and the device D will perform its further function of preventing the rails from returning to their original set positions 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 position under the bias of the spring means of the device D and against the retarding force exerted by the bufiing means of the device D. When the rails reach their full normal positions, the looking plunger will return to its locking position due to its associated biasing means, and all parts will be restored to the positions shown.

I have found that with the switch points biased to their normal positions by means of the device D in .the manner described above, each time a pair of the wheels of a car which is trailing the switch moves past the switch points, a slight amount of return movement of the switch points, usually about A, inch, takes places before the bufling action of the device D becomes effective, and as a result when the buffing action does become effective, a certain amount of momentum of the points and of the parts of the bufiing device which move with the points has been built up due in part to the action of the spring biasing means of the device, and in part to the fact that since thepoints when trailed are moved past their mid stroke positions the inherent resiliency of the points sets up a force which tends to return the points to their mid stroke positions. Consequently, when the bufling action of the device D does become effective, the'device D momentarily loses its characteristic as a fiexiblemember, and' I acts as a rigid link. As a result, the momentum of the moving parts including that portion of the device D which moves with the switch points is transmitted to the operating rod ll so that this red, instead of being in tension momentarily becomes a compression member. Unless some means are provided to prevent it, the sudden shock caused, by this momentary shift in the direction of the load on rod II is transmitted to the operating parts of the mechanism B, and since there is necessarily a certain amount of clearance between these parts, wear on all parts including the track switch itself is greatly accelerated. This is undesirable and according to my present invention, I provide means which I shall now describe whereby the shock due to the sudden reversal of. the load in the device D under the conditions described above is prevented from reachingany of the working parts of the mechanism.

Referring now also to Figs. 2 and 3, this means comprises a stop member in the form of a stop screw i1 adjustably screwed through an upstanding lug l8 provided on the screw jaw 9. The head of the screw I! is rounded to enable it to seat against a suitable stop surface 19 provided on the side of the mechanism casing, and the screw is inclined at a suitable angle to cause it to engage the casing at a point where the casing is strongest. The inclination of ,the stop screw also provides clearance between a lock washer 20 and lock nut 2| which are provided on the stop screw, and a lockwasher 22 and look nut 23 which are provided on the operating rod II.

The stop screw I1 is so adjusted that when the switch operating crank is rotated to the extreme position which it occupies when the switch points are held in their normal extreme positions by the biasing force exerted by the device D, the screw will just touch the stop surface IS on the mechanism case, and it will be seen, therefore, that any force which is exerted on the rod I I in the direction to move it toward the mechanism B will be transmitted from the rod through the screw jaw, the lug l8 and the stop screw I! to the mechanism case rather than to the working parts of the mechanism. It follows, therefore, that when a train trails the switch, the stop screw will act to effectively prevent wear on the working parts due to the momentary reversal in the force which is exerted on the rod H each time the wheel of a train which is trailing the switch moves past the switch points, whereby the life of the switch operating apparatus is greatly lengthened.

It should be noted that since the rod H is in tension at all times except for the brief interval in which the rod becomes a compression member following the passage of each pair ofwheels of a trailing train over the switch the stop means does not interfere at any time with the normal opera tion of the parts.

It should also be noted that while I have shown my invention applied to only one form of railway switch operating mechanism, it can be applied to any of the usual forms of commercial switch stands. the stop can be made to bear directly against the mechanism case, an angle or other suitable structural member can be bolted to the ties to absorb the thrust transmitted through the stop member.

One advantage of apparatus constructed in accordance with my invention is that since the stop is adjustable, it is possible to eliminate any reverse motion of the rod ll tending to cause wear not only when the layout is first installed,

but also throughout the life of the apparatus.

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:

l. The combination with a spring switch connected with a switch operating mechanism through means including an operating rod normally in tension but subjected to sud-den reversals in the force applied thereto while a train is trailing the switch which reversals at times cause the rod to be in compression, of stop means operatively associated with said operating rod and adjusted to prevent movement of said operating rod toward said switch operating mechanism beyond the extreme position to which it is normally moved by said switch operating mechanism to move the switch points to their normal set positions, said stop means being wholly independent of any of the operating parts of said switch operating mechanism.

2. The combination with a spring switch connected with a switch operating mechanism through a combined biasing and bufling device including a movable operating rod, of adjustable stop means operatively associated with said operating rod and adjusted to prevent movement of said operating rod beyond th'e extreme position to which it is normally moved by operation of said operating mechanism to move the switch points to their normal set positions to prevent the transmission to the operating parts of said mechanism of forces resulting from the return movement of the switch points toward their normal set positions while a train is trailing the switch.

3. The combination with a spring switch connected with the operating crank of a switch oper-' ating mechanism through acombined biasing If the stand is not constructed so that and bufling device including an openating rod and an adjustable screw jaw adjustably mounted on said operating rod and pivotally connected to said operating crank, of a lug formed on said screw jaw and provided with a tapped hole, and a set screw adjustably screwed through said tapped hole and adapted to engage a fixed part of said operating mechanism, said screw being adjusted to prevent movement of said operating rod toward said mechanism beyond the extreme position to which it is normally moved by said switch operating mechanism to move the switch points to their normal set positions.

4. The combination with a spring switch connected with the operating crank of a switch operating mechanism through a combined biasing and buffing device including an operating rod and an adjustable screw jaw adjustably mounted on said operating rod and pivotally connected to said operating crank, of a lug formed on said screw jaw and provided with an inclined tapped hole, a set screw adjustably screwed through said tapped hole and adapted to engage the side of said operatingmechanism, said screw being adjusted to prevent movement of said operating rod toward said mechanism beyond the extreme posi tion to which it is normally moved by said switch operating mechanism to move the switch points to their normal set positions, and means to lock said screw in its adjusted position.

5. The combination with a spring switch connected with .a switch operating mechanism through means including an operating rod subjected to sudden reversals in the force applied thereto while a train is trailing the switch, of stop means operatively associated with said operating rod and adjusted to prevent movement of said operating rod beyond the extreme position to which it is normally moved by said switch operating mechanism to move the switch points to their normal set positions, said stop means being wholly independent of any of the operating parts of said switch operating mechanism.

6. The combination with a spring switch connected with a switch operating mechanism through a device which acts to yieldably resist movement of the switch points away from a set position and to retard the return movement of the points to their set position when a train trails the switch of an adjustable stop screw attached to a portion of said device that is non-resiliently connected to the operating mechanism and adjusted to cooperate with a fixed part of said mechanism upon a reversal in the direction of the force applied to said device while a train is trailing the switch to prevent the transmission of shock through said device to the operating parts of said mechanism.

7. The combination with a spring switch connected with a switch operating mechanism through a device which acts to yieldably resist movement of the points away from a set position and to retard the return movement of the points to their set position when a train trails the switch of adjustable stop means interposed between and cooperating with a portion of said device that is HERBERT L. BONE.

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