US2061752A - Railway switch operating apparatus - Google Patents

Description

H. L. BONE Nov. 24, 1936.

RAILWAY SWITCH OPERATING APPARATUS 2 Sheets-Sheet l I Filed NOV. 16', 1933 bvmvmk Herbert L .Bone

,Qm/ww HIS ATTORNEY" Nov. 24, 1936. H. L. BONE 2,061,752v

RAILWAY SWITCH OPERATING APPARATUS Filed Nov. 16, 1935 2 Sheets-Sheet 2 FigA INVENTOR HQPbQPtLBOIZQ HIS ATTORNEY Patented Nov. 24, 1936 UNITED STATES attusz PATENT @TTEQE RAILWAY SWITCH OPERATJING APPARATUS Application November 16, 1933, Serial No. 698,307

18 Claims.

My invention relates to railway switch operating apparatus, and particularly to apparatus for operating spring switches.

One object of my invention is to provide means for decreasing the pressure which the points of a spring switch exert against the wheels of a car while a car is trailing the switch, without decreasing the force which is efiective for holding the switch points in either of their extreme positions when they are moved to such extreme positions by the switch operating means, thus materially reducing the wear on the switch points and hence increasing the life of the switch.

Another object of my invention is to provide improved means for decreasing the slapping of the points of a spring switch during trailing moves over the switch.

Other objects of my invention will appear as the description proceeds.

I will describe two forms of apparatus embodying my invention, and will then point out the novel featuresthereof in claims.

In the accompanying drawings, Fig. 1 is a topplan view, partly cross-sectioned, showing a spring switch provided with one form of switch operating apparatus embodying my invention. Fig. 2 is a vertical sectional view of the device D forming part of the apparatus illustrated in Fig. 1 and embodying my invention. Fig. 3 is a sectional view on the line III--III of Fig. 2. Fig. 4 is a top plan view, partly cross-sectioned, showing a spring switch provided with another form of switch operating apparatus embodying my invention.

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

Referring first to Fig. 1, the reference character A designates a railway switch, and the reference character B designates a device for operating the switch A. The switch A comprises, as usual, two fixed rails l and l and two movable switch points 2 and 2 the switch points being connected together adjacent their tips by-a head rod 3.

The operating device B, as here shown, comprises a switch stand l having its base t spiked or otherwise secured to the ties adjacent the switch A. A gear shaft 6 is journaled in the switch stand 4 and carries a crank 55 and a gear segment i. The gear segment 1 meshes with a pinion gear 8 keyed to a pinion shaft 9. The pinion shaft 9 extends through the side of the switch stand 4, and has attached to its outer end the usual weighted switch-throwing lever it.

The crank 5 of the switch-throwing device B is connected with the head rod 3 of switch A by means of a link it and a spring connecting rod C. The spring connecting rod C may have any suitable form, but in the well-known form here shown, this connecting rod comprises a cylindrical housing l l having a lateral extension Hi fastened to the front rod 3. The right-hand end li of the housing M has a smaller diameter than the body of the housing, while the left-hand end is threaded to receive a cap l5 having an end th similar to the end M Slidably mounted in the opening in the end M is a sleeve It provided with an annular flange l6 located within the housing it, and similarly mounted in the opening in the end l5 is a sleeve il provided with an annular flange H located within the housing It. A spring rod i2 extends through both sleeves it and ll with sufficient clearance to permit the rod to slide freely in the sleeves, and this rod carries a compression spring which engages the sleeves at the annular flanges and urges the sleeves toward the positions in which the annular flange 18 of the sleeve it engages the shoulder formed on the inside of the housing it by the end l i and the annular flange li of the sleeve ll engages the shoulder formed on the inside of the cap it by the end M The spring rod 52 is pr vided with an annular shoulder is for at times engaging the outer end of the sleeve it, and with a nut 58 for at times engaging the outer end of the sleeve 51. The spring rod 52 is also provided with a nut as for locking the nut 58 in an adjusted position. The right-hand end of the spring rod i2 is pivotally attached to the link I l.

The apparatus thus far described is wellknown and its operation will be made clear as the description proceeds.

Associated with the switch A, the switch operating device B, and the spring connecting rod C is a combined biasing and buffing device D embodying my present invention, which device I will now describe. As best seen in Figs. 2 and 3, the device D comprises, in the form here illustrated, a casing having a cylinder 2i extending therethrough. One end of the cylinder ill is closed by a cylinder head 22, and the other end is closed by a cylinder head 23. A piston rod 2i extends into the cylinder Zi through a stuffing box 23 and through a suitable hole 23 in the cylinder head 23, and is attached, at its inner end, to a reciprocable piston 25 by means of a nut 25. A spring 2'? is mounted in the cylinder Zi between the cylinder head 22 and the piston 25, and constantly biases the piston toward the right-hand end of the cylinder.

The cylinder wall is provided in its left-hand end with a leak groove 2| which permits fluid to flow past the piston 25 under certain conditions which will be made clear hereinafter.

Located in the casing 2i above the cylinder 2| is a reservoir Zi which is constantly connected with the cylinder 2i on the right-hand side of the piston 25 by means of a port 28. The reservoir is also connected with the cylinder 2| on the left-hand side of the piston 25 by means of a port 29, a regulating valve 30, and a port 3!. The regulating valve 30 may be of any suitable type, but as here shown this valve is similar in all respects to that described in Letters Patent of the United States No. 1,830,803, granted to W. C. McWhirter, on Nov. 10, 1931, for Railway switch operating apparatus. It is believed, therefore, that for purposes of the present disclosure, it is sufficient to state that the regulating valve 30 comprises a rotatable valve member 30 provided with a plurality of restricted orifices 30 of difierent sizes which extend through the side of the valve member in radial spaced relation, and any one of which may be brought into registration with the port 29 by turning the valve member 30 to the proper position.

The reservoir Zl is further connected, by means or" two coaxial ports 32 and 33 with a fluid chamber 22 formed in the cylinder head 22, and the fluid chamber 22*, in turn, is at times connected with the cylinder 2| on the left-hand side of the piston 25 by means of a poppet valve 34. As here shown, the poppet valve 34 comprises a valve member 34 formed on one end of a valve stem 34", and cooperating with a valve seat 35 provided in a valve body 36 which is secure-d to the cylinder head 22, within an opening 31, by means of bolts 38. The right-hand end of the valve stem 34 is fluted and extends into a port 3E3 formed in the valve body 36, while the left-hand end of the valve stem slides in a guide bearing 39 formed in an apertured member 40 which is screwed into the left-hand end of the valve body 35. A spring 4| surrounds the valve stem 341 between the valve body and a washer 42 which abuts against a pin 43 carried by the valve stem, and constantly biases the valve to a closed position.

The poppet valve 34 is controlled by a cam 44 secured to a vertical shaft 45 which is journaled at its lower end in a bearing 46 provided in the lower part of the cylinder head 22. The upper end of the shaft 45 extends out of the cylinder head 22 through a bearing 4'! and a packing gland 48, and is attached to an operating arm 49 (see Fig. 1). The cam 44 is provided with two cam lobes 44 and 44 as shown in Fig. 3, these lobes being so proportioned that when either lobe is in engagement with the valve stem 34 of the valve 34, the valve 34 will be held in an open position.

The reservoir 21 cylinder 2N and fluid chamber 22 are all intended to be filled with a suitable fluid, such as oil, and in order to permit the insertion of fluid into these parts, the reservoir wall is provided with a hole 50 which is normally closed by a screw plug i.

Referring now again to Fig. 1, the biasing and buffing device D is pivoted at its rear end on a pivot pin 52 mounted in a supporting stand 53, and the piston rod 24 of the bufiing device is connected by means of a pin 54 to the long arm 54* of a bell crank lever 55. The bell crank lever 55 is fulcrumed on a pin 56 mounted in a crank stand 51, and the short arm 55 thereof is connected by means of a pin 58, a link 59, and a pin 60 with the head rod 3 of the switch A. The operating lever 49 of the device D is operatively connected with the spring rod l2 of the spring connecting rod by means of a link 6|.

In explaining the operation of the apparatus as a whole, I will assume that the parts are all in their normal positions in which they are illustrated in the drawings, and that it is desired to move the switch points from their normal positions to their reverse positions. To do this, the hand-throw lever of the switch operating device B is rotated from the position shown through an angle of 180 in a clockwise direction, thereby rotating gear segment 1 and crank 5 in a clockwise direction, and hence moving link II and spring rod I2 toward the right. The motion of the spring rod I2 toward the right causes a force to be exerted on the switch points 2 and 2 through the medium of nuts l9 and I8, sleeve I1, spring 20, sleeve l 6, the end 14 of housing I4, housing l4, and spring rod 3, which force moves the switch points to their reverse positions. During the movement of the switch points to their reverse positions, bell crank lever 55 is rotated in a clockwise direction, and device D, due to its connection with the bell crank lever, is rotated in a counterclockwise direction. The lever 55 and device D are so arranged, and the parts are so proportioned that the rotation of these parts which takes place under these conditions will cause piston 25 of device D to move inwardly in the cylinder 2| in opposition to the bias of spring 21, while the switch points are being moved to their mid stroke positions, and then outwardly during the balance of the stroke of the switch points in such manner that when the switch points reach their full reverse positions, the piston 25 will be restored to its normal position in which it is shown in Fig. 2. It will be apparent, therefore, that during the first half of the movement of the switch points to their reverse positions the spring 21 of device D will exert a force on the switch points which opposes their motion, but that, during the second half of the movement of the switch points to their re verse positions, the spring 21 will then exert a force on the switch points which aids their motion. It will also be apparent that due to the manner in which the bell crank lever 55 and device D are arranged, these parts function like a toggle, with the result that the force which is exerted on the switch points by the spring 21 opposing their movement to their reverse positions will decrease as the switch points approach their mid stroke positions, while the force which is exerted on the switch points by the spring 21 aiding their movement to their reverse positions will increase as the points move away from their mid stroke positions. It will further be apparent that in order to avoid excessive deflection of the spring 20 of the spring connecting rod C, this spring should be made sufiiciently stiff to exert a somewhat greater force on the points at the beginning of their movement to their reverse positions than is exerted on the points by the spring 21. During the counter-clockwise rotation of the device D, the camshaft 45, due to its connection with the spring rod 12, is simultaneously rotated in a clockwise direction, thus causing cam 44 to be rotated in a clockwise direction. The construction of cam 44 is such that cam lobe 44 will remain in engagement with valve stem 34 of valve 34 and will hold this valve open at least until piston has moved inwardly in cylinder 2 i past the righthand end of leak groove 2H, and that cam lobe 44 will move into engagement with the valve 34 and reopen this valve before the piston 25 has again been moved outwardly past the right-hand end of the leak groove. It will be apparent, therefore, that during the movement of the switch points to their reverse positions, fluid in cylinder 2| is free to flow from one end of the cylinder to the other through valve 34, fluid chamber 22 ports 33 and 32, reservoir 2| and port 28 as long as piston 25 occupies any position to the right of the right-hand end of leak groove 2 l and that when the piston 25 has been moved to a position in which it is just past the right-hand side of the leak groove, fluid is then free to flow from one end of the cylinder 2i to the other end through leak groove 2 It follows that under the conditions just described, the device D exerts practically no resistance to the movement of the switch points other than that due to the spring 21.

After the switch points have been moved to their reverse positions by the device B in the manner just described, they may be restored to their normal positions by restoring the switch-throwing lever I0 to the position in which it is shown in the drawings. The operation of the apparatus under these conditions is just the reverse of that which takes place when the switch points are moved from their normal positions to their reverse positions, and will be readily understood from the foregoing and from an inspection of the drawings without further description.

I will now assume that the parts are in their normal positions as shown in the drawings, and that a vehicle trails the switch. Under these conditions, as the wheels of the vehicle roll along the fixed rail I and movable switchpoint 2 the switch points 2 and 2 will be forced toward their reverse positions by the wheels, and since spring rod l2 of spring connecting rod C is now held stationary by virtue of its connection with the switch operating device B, spring 20 will become compressed and will exert an increased force on the switch points tending to restore them to their normal positions. The movement of the switch points toward their reverse positions under these conditions will also cause bell crank lever 55 to be rotated in a clockwise direction and device D to be rotated in a counter-clockwise direction in the same manner as when the switch points are moved from their normal positions to their reverse positions by the switch operating device B, with the result that while the switch points are being moved to their mid stroke positions, the spring 21 will exert a force on the points which aids that exerted on the points by the spring 20 of the spring connecting rod C in tending to restore the points to their normal positions, but that, as soon as the switch points have been moved past their mid stroke positions, the spring 21 will then exert a force on the points which opposes that exerted on the points by the spring 20 and which tends to move the points toward their reverse positions. The stiffness of the spring 20 is such, and the parts are so proportioned that the force which is exerted on the switch points by the spring 20 under these conditions will always be greater than that exerted on the points by the spring 21, but that the result-' ant force which is exerted on the points under these conditions tending to restore the points to their normal positions will decrease as the points are moved away from their normal positions by an amount which is substantially proportional to the displacement of the points. During the move ment of the switch points toward their reverse positions, camshaft 45 is held stationary due to its connection with spring rod [2, and cam 44 is therefore likewise held stationary. As a result, valve 34 is held open by lobe 44 of cam 44 until the switch points have been moved to their mid stroke positions, whereupon this valve is permitted to close under the bias of the spring 4|. Spring 4| is made relatively light so that very little force is required to open this valve, and it follows that the fluid in the buffing device D does not offer any resistance to the movement of the points toward their reverse positions under these conditions. As soon, however, as the switch points start to return to their initial positions, due to the bias of spring 29, spring ii closes valve 34, thus preventing the fluid in cylinder 2V on the left-hand side of piston 25 from flowing past this valve, and since piston 25 then occupies a position to the right of leak groove 2 I and is moving toward the left in. cylinder 2%, the return movement of the switch points is limited to the rate at which the fluid in cylinder 25 on the left-hand side of piston 25 can flow through regulating valve 30, until after piston 25 has been moved past the right-hand end of leak groove N at which time, the switch points will have been moved nearly to their mid stroke positions. The rate at which fluid can flow through regulating valve may be varied in the manner previously described, and this rate will usually be adjusted to such a value that the switch points are prevented from moving to their mid stroke positions under the action of the spring 20 until a time interval has elapsed which is larger than the time interval required for adjacent trucks of a vehicle to pass the switch points whenthe vehicle is moving at the usual trailing speeds. After the switch points have been restored to their mid stroke positions by spring 20, valve 34 is reopened by cam 4t, and no further retardation of the points by the device D takes place. Furthermore, as soon as the points have been moved past their mid stroke positions by the spring 20, spring 21 exerts a force on the points which aids that exerted on the points by the spring 20, and it will be apparent, therefore, that the remainder of the movement of the switch points to their normal positions is relatively rapid. When the switch points have been restored to their full normal positions, all parts are then restored to their normal positions in which they are shown in the drawings.

When the switch occupies its reverse position 7 and a vehicle trails through the switch, the apparatus functions in a manner similar to that just described, and it is thought, therefore, that the operation of the apparatus under these conditions will be readily understood from the foregoing and from an inspection of the drawings without describing it in detail.

It should be particularly pointed out that with the apparatus constructed in the manner just described, the spring 20 of the spring connecting rod C and spring 21 of the device D will preferably be so constructed and the parts will be so proportioned that the total force which is exerted on the switch points by these two springs when the switch points are moved to either their normal or their reverse positions by the switch operating device B will be equal to that customarily provided under similar conditions in spring switches as they have heretofore been constructed, and that, with the parts constructed and proportioned in this manner, the force which is exerted on the points tending to restore them to their original extreme position when they have been moved away from such position by a trailing train will be only a fraction of that exerted on the points in the prior types of spring switches. For example, in the priortypes of spring switches the force which is exerted on the switch points by the spring of the spring connecting rod tending to hold the points in either extreme position when they have been moved to such extreme position by the switch operating device is usually 1000 pounds, and when a train trails the switch this force usually increases to 2000 pounds. With apparatus embodying my invention, however, assuming that when the switch points are moved to either extreme position by the device D, a force of 600 pounds is exerted on the switch points by the spring of the spring connecting rod and a force of 400 pounds by the spring 2? of the device D, and. that the force which is exerted on the points by the spring 20 of the spring connecting rod when a train trails the switch increases to 900 pounds, then the force which is normally exerted on the points will be the same as in the prior types of spring switches, but the force which is exerted on the points while a train is trailing the switch will be 900 minus 400, or 500 pounds, which latter force is only one fourth of that which is exerted on the points under like conditions with the prior types of spring switches. It follows that with apparatus embodying my invention, the wear on the switch points will be much less than in the prior types of spring switches.

It should also be pointed out that in the prior types of spring switches in which buffing devices are provided, there is a certain amount of kickback of the switch points before the buffing action becomes effective. This kick-back is due to the reversal of motion of the parts, and occurs partly in the buffing device itself and partly in the connections between the buffing device and the switch points. With apparatus embodying my invention, this kick-back has not been completely eliminated, but it has been considerably reduced for two reasons. In the first place, the ratio between the movement of the piston in the buiiing device and the movement of the head rod 3 can be made larger than unity, say two to one, so that a given amount of kick-back in the buffer will only result in one-half this amount of kick-back of the head rod 3. In the second place, the relation of the bufiing device and the bell crank lever 55 is such that the lost motion in the pivot pins which supports these parts as well as in the other pin connections is taken up in the proper direction to eliminate all kickback when the direction of motion of the head rod 3 is reversed, as it is each time a pair of wheels of a trailing vehicle moves past the switch points.

Referring now to Fig. 4, in the modified form of the apparatus here shown, the head rod 3 and switch operating device B are located somewhat farther back from the tips of the switch points than is the usual practice, and the head rod is connected, at the end opposite to the device B, with the piston rod 62 of a bufiing device E. The bufiing device E may be of any suitable type, but as here shown, this buffing device is similar in all respects to the buiiing device shown and described in Letters Patent of the United States No. 1,869,- 604, granted to William C. McWhirter, on Aug. 2, 1932, for Buffing devices for railway switches and the like. t is believed, therefore, that for purposes of the present disclosure, the following brief description of this buffing device will sufiice. This bufiing device includes in addition to the piston rod 62 a camshaft 63 extending into the case of the device and controlling a valve mechanism not shown. Attached to the outer end of the camshaft 63 is a crank 6% which is connected by a link 65 with the spring rod [2 of the spring connecting rod C. If, when the switch points 2 and 2 of the switch A are in their normal positions, as shown in Fig. 1, they are moved to their reverse positions by the switch operating device B, the piston rod 62 will be moved outwardly in the device, and the camshaft 63 will be rotated in a counter-clockwise direc tion, as viewed from the top in Fig. 1. The construction of the device E is such that, under these conditions, the piston rod 62 will be permitted to move with substantially no resistance, and the bufiing device will exert practically no retarding action on the switch points. Conversely, if the switch points are moved from their reverse positions to their normal positions by the switch operating device B, the piston rod E32 will be moved into the device, and the camshaft 83 will be rotated in a clockwise direction, as viewed from the top 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 camshaft 03 will remain stationary, and, under these conditions, the action of the device is such that the movement of the switch points away from the positions which they previously occupied will be unresisted by the buffing device, but that, when the switch points are being restored to the positions which they previously occupied, by the spring 20 of the spring connecting rod C, the bufiing device will act to retard this latter movement.

The reference character U designates a biasing device comprising a cylinder 66 containing a rcciprocable piston 67 attached to one end of a piston rod 68, the piston being biased to a forward position in the cylinder 66 by means of a spring 69 interposed between the piston rod and the rear end of the cylinder. The biasing device is pivotally supported at its rear end on a fulcrum pin 10 mounted in a suitable stand it secured to the ties which support the switch, and the piston rod 68 of the biasing device is connected at its free end with the long arm '12 of a bell crank lever 72. The bell crank lever "E2, in turn, is pivotally supported in a crank stand l3 and has its short arm i2 operatively connected by means of a link M with a front rod '65 which connects the tips of the switch points in the usual manner.

The operation of the apparatus as a whole is as follows. The parts are so proportioned that when the switch occupies any position between its mid stroke position and its normal position, the spring 69 of the biasing device U will act through the bell crank lever l2, link M and front rod 75 to exert a force on the switch points which urges them to their normal positions, but that, when the switch points occupy any positions between their mid stroke positions and their reverse positions, the spring 69 of the biasing device U will then act through the bell crank lever '52, link Hi and front rod 75 to exert a force on the switch points which urges the switch points toward their reverse positions. It will be apparent, therefore, that when the switch points are moved to either their normal or reverse extreme positions, they will be biased to such extreme positions by both the spring 20 of the spring connecting rod C and also by the spring 69 of the biasing device U. It will also be apparent that when the switch operating device B is operated to move the switch points from either extreme position to the other extreme position, the spring 69 of the biasing device U will exert a force on the points which opposes their motion until the points have been moved to their mid stroke positions, after which the spring 69 will then exert a force on the points which aids their motion. It will further be apparent that in order to avoid excessive deflection of the spring 20 of the spring connecting rod C during movement of the switch points from either of their extreme positions to their other extreme positions, the parts will have to be so proportioned that the force exerted on the points by the spring 20 at the beginning of their movement will be somewhat greater than the opposing force which is exerted on the points by the spring 69 of the biasing device U. It will be understood, of course, that during movement of the switch points from either of their extreme positions to their other extreme positions, the buffing device E will function in the manner previously pointed out.

When the switch occupies its normal position and a train trails the switch, the spring 20 of the spring connecting rod C will become compressed and will exert a force on the switch points tending to restore them to their original positions in the manner previously described in connection with Fig. 1, and the buffing device E will perform its usual function of preventing the switch points from snapping back after the passage of each pair of wheels. Furthermore, during the movement of the switch points away from their normal positions, bell crank lever 12 will be rotated in a clockwise direction thus causing the biasing device U to be rotated in a counter-clockwise direction, and as a result, during that portion of the movement of the switch points away from their normal positions in which the switch points are between their normal positons and their mid stroke positions, the biasing device U will exert a force on the switch points which aids that exerted on the switch points by the spring 20 of the spring connecting rod C in urging the switch points to their normal positions, but that as soon as the switch points have been moved past their mid. stroke positions, the biasing device U will then exert a force on the switch points which opposes that exerted on the points by the spring 20 of the spring connecting rod 0 and which aids the motion of the points away from their normal positions. The parts are so proportioned that the force which is exerted on the switch points by the spring connecting rod C tending to restore the points to their normal positions while a train is trailing the switch will always exceed that exerted on the points by the biasing device U tending to move them away from their normal positions, and that, the resultant force which is exerted on the points tending to restore them to their normal positions while a train is trailing the switch will be less than that which was initially exerted on the points tending to retain them in their normal positions, by an amount which is substantially proportional to, and which increases with, the displacement of the points from their normal positions. When the train has completely passed the switch, the

switch points will return to their normal positions due to the bias of the spring 26 in the spring connecting rod. Their motion, until the points have been moved almost to their mid positions, is retarded by the buffing device E in the usual manner, and is opposed by the biasing device U. As soon as the points have been moved past their mid positions, however, the bufiing device E no longer retards the movement of the points, and the biasing device U then exerts a force on the points which accelerates their movement. When the points reach their normal positions, all parts are then restored to their normal positions in which they are shown in the drawings.

When the switch is moved to its reverse position by the switch operating device B and a train trails the switch, the operation of the apparatus is similar to that just described except that the direction of movement of the parts is reversed. It is believed, therefore, that this operation will be understood from an inspection of the drawings without further description.

It should be particularly pointed out that with the apparatus constructed as shown in Fig. 4, when a train trails the switch, the tips of the switch points are held back from engagement with the car wheels, and since the worst wear on the points occurs at their tips, it follows that the life of the switch is materially lengthened. The reason why the tips of the points are held back under these conditions is that, as was previously pointed out, when the switch points have been forced past their mid stroke positions by a trailing train, the biasing device U exerts a force on the points tending to hold them in their trailed positions, and before any movement of the points toward their original positions can occur, this force has to be overcome. Any force which is exerted on the points tending tov overcome the force exerted on the points by the biasing device U will be due to the bias of the spring 20 of the spring connecting rod and will have to be transmitted to the tips of the points through the portion of the points between the head rod and the front rod. This portion of the points is relatively flexible and is also relatively long, so that before enough force can be developed at the points of the rails to overcome the force due to the biasing device, a considerable amount of flexing of the points will occur, and the parts are so proportioned that the buffing device will prevent the points from moving sufficiently while the train is trailing the switch to cause the necessary flexing.

Although I have herein shown and described only two forms 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. In combination, a railway switch movable between two extreme positions, a switch operating device movable between two extreme positions, means for connecting said device with said switch in such manner that said switch will be biased to one extreme position or the other according as said device is moved to its one extreme position or its other extreme position, and biasing mechanism connected with the switch and acting to constantly bias said switch toward its nearest extreme position with a force that is somewhat less than that which is exerted on the points at any time by said connecting means.

2. The combination with a railway switch and an operating device connected with the movable points of said switch through the medium of a spring connecting rod, of a biasing device, and means including a bell crank lever for connecting said biasing device with the points of said switch in such manner that when said switch is moved to either extreme position by said operating device said biasing device will exert a force on the switch points which aids that exerted on the points by said spring connecting rod in biasing the points to the extreme position which they then occupy but that when the switch points are moved a predetermined distance away from either extreme position by a trailing train said biasing device will then exert a force on the switch points which opposes that exerted on the points by the spring connecting rod.

3. The combination with a railway switch and an operating device connected with the movable points of said switch through the medium of a spring connecting rod, of a biasing device, and linkage for connecting said biasing device with the points of said switch in such manner that when said switch is moved to either extreme position by said operating device said biasing device will exert a force on the switch points which aids that exerted on the points by the spring connecting rod in biasing the points to the extreme position which they then occupy but that when the switch points are moved a predetermined distance away from either extreme position by a trailing train said biasing device will then exert a force on the switch points which opposes that exerted on the points by the spring connecting rod, the parts being so proportioned that the resultant force which is exerted on the points when they are in a trailed position will be sufficient to restore the points to their original positions after the trailing train has passed the switch but will be less than that which is nor mally exerted on the points tending to retain them in their extreme positions.

4. The combination with a railway switch and an operating device connected with the movable points of said switch through the medium of a spring connecting rod, of a biasing device pivotally supported at one end in the trackway and operatively connected at the other end with the points of said switch in such manner that when said switch is moved to either extreme position by said operating device said biasing device will exert a force on the switch points which aids that exerted on the points by the spring connecting rod in biasing the points to the extreme position which they then occupy but that when the switch points are moved away from either extreme position past their mid stroke position by a trailing train said biasing device will then exert a force on the switch points which is less than and which opposes that exerted on the points by the spring connecting rod.

5. The combination with a railway switch and an operating device connected with the movable points of said switch through the medium of a spring connecting rod, of a biasing device, means for connecting said biasing device with the points of said switch in such manner that when said switch is moved to either extreme position by said operating device said biasing device will exert a force on the switch points which aids that exerted on the points by the spring connecting rod in biasing the points to the extreme position which they then occupy but that when the switch points are moved a predetermined distance away from either extreme position by a trailing train said biasing device will then exert a force on the switch points which is less than and which opposes that exerted on the points by the spring connecting rod, and means for retarding movement or" the switch points when and only when they are being moved toward an extreme position after they have been moved away from such extreme position by a trailing train.

6. The combination with a railway switch comprising a movable point and an operating device connected with said point through the medium of a spring connecting rod, of means eiiective while a train is trailing the switch for exerting on said point a force which is less than and which acts in opposition to the force which is then exerted on said point by the spring in said spring connecting rod, and means for retarding movement of said point by said connecting rod when and only when the movement is independent of any movement of said operating device.

7. In combination, a railway switch comprising a pair of switch points, spring means operatively connected with the switch points for yieldably resisting movement of the points in opposite directions by a train trailing through the switch and for returning the switch points to their original positions after the train has passed through the switch, biasing means independent of said spring means for biasing the points to their nearest extreme position, whereby when the switch points are moved from an extreme position past their mid stroke position by a trailing train said biasing means exerts a force on the points which acts to decrease the total force urging the points toward their original positions, and means for retarding the return movement of the switch points in opposite directions.

8. In combination, a railway switch comprising a pair of switch points, spring means operatively connected with the switch points for yieldably resisting movement of the points in opposite directions by a train trailing through the switch and for returning the switch points to their original positions after the train has passed through the switch, biasing means operatively connected with the points for yieldably resisting movement of the points in opposite directions by a train trailing through the switch until the points have been moved past their mid stroke positions and. for subsequently aiding further movement of the points by the train, and buffing means effective for retarding the return movement of the points in opposite directions.

9. In combination, a railway switch comprising a pair of switch points connected by a head rod and movable between two extreme positions, a switch operating device movable between two extreme positions, means including a spring con necting rod for connecting said device with said head rod, a combined biasing and bufiing device, means for operatively connecting said biasing and buffing device with said head rod in such manner that the switch points are biased toward their nearest extreme positions by said biasing and buffing device, and means controlled by said switch operating device for controlling the buiiing action of said biasing and buiiing device in such manner that the bufling action of said device is effective when and only when the switch points are being moved by the spring in said spring connecting rod independently of any movement of said switch operating device.

10. In combination, a railway switch comprising a pair of switch points connected by a head rod and movable between two extreme positions, a switch operating device movable between two extreme positions, and means including a spring connecting rod for connecting said device with said head rod, the combination with the aforementioned instrumentalities of a biasing and bufiing device pivotally supported at one end in the trackway and comprising a cylinder containing fluid, a piston reciprocable in said cylinder and connected with the switch in such manner that the piston will be moved in one direction in said cylinder during movement of said switch points toward their mid stroke positions and in the opposite direction during movement of said switch points away from their mid stroke positions, a spring in said cylinder opposing move ment of said piston in said one direction, a reservoir, means for constantly connecting the end of said cylinder toward which said piston moves when it is moved in said opposite direction with said reservoir, means including a restricted orifice for connecting the other end of said cylinder with said reservoir, a Valve controlled by said operating device, and a bypass around said restricted orifice controlled by said valve.

11. In combination, a railway switch comprising a pair of switch points connected by a head rod and movable between two extreme positions, a switch operating device movable between two extreme positions, means including a spring connecting rod for connecting said device with said head rod, the combination with the aforementioned instrumentalities of a biasing and bufling device pivotally supported at one end in the trackway and comprising a cylinder containing fluid, a piston reciprocable in said cylinder and connected with the switch invsuch manner that the piston will be moved in one direction in said cylinder during movement of said switch points toward their mid stroke positions and in the opposite direction during movement of said switch points away from their mid stroke positions, a

. spring in said cylinder opposing movement of said piston in said one direction, a reservoir, means for constantly connecting the end of said cylinder toward which said piston moves when it is moved in said opposite direction with said reservoir, means including a restricted orifice for connecting the other end of said cylinder with said reservoir, a valve, a bypass around said restricted orifice controlled by said valve, a leak groove in said one end of said cylinder, and means controlled by said switch operating device for controlling said valve in such manner that said valve will be closed during movement of said piston when and only when said piston is being moved in said one direction due to movement of said switch points by said spring connecting rod independently of any movement of said switch operating device.

12. In combination, a railway switch comprising a pair of switch points connected at their tips by a front rod and at a point some distance back from their tips by a head rod, a spring connecting rod connected with the head rod and 'selectiv-ely operable in opposite directions to close the switch after a train has trailed therethrough, a bufiing device operatively connected with the head rod for resisting the action of the spring connecting rod to close the switch, manually operable means operatively connected with the spring connecting rod for throwing the switch, and means operatively connecting said manually operable means with said buifing device whereby the operation of said manually operated means automatically reverses the direction in which the action of the spring connecting rod is resisted by the bufiing device, the combination with the aforementioned instrumentalities of a device comprising a cylinder pivotally supported at one end in the trackway, a piston rod extending into the other end of said cylinder and attached to a piston reciprocable in said cylinder, a spring in said cylinder biasing said piston toward said other end of the cylinder, and means for connecting said pistonrod with said front rod in such manner that the switch points are always biased to the nearest extreme positions by said biasing device, the parts being so proportioned that the force exerted on the switch points by said biasing device will always be somewhat less than that exerted on the points by said spring connecting rod.

13. In combination, a railway switch of the type which is adapted to be trailed, means connected with the switch points at a point some distance back from their tips for moving the switch points to their two extreme positions and for biasing the switch points to the extreme position to which they are moved, a bufiing device connected with the switch points and effective for retarding movement of said points by said means when the points have been moved away from an extreme position by a trailing train, and a biasing device connected with the tips of the points and eflective for biasing the points to their nearest extreme position, the parts being so proportioned that when the switch points are moved past their mid stroke position by a trailing train the force which is exerted on the points by said biasing device tending to move the points toward their nearest extreme position will be less than that which is exerted on the points by said means tending to restore the points to their original positions but will be sufficient to cause considerable flexing of the rails between said device and said means before any movement of the tips of the points toward their original positions will occur and that as long as the train continues to trail the switch said biasing device will prevent said means from moving the points toward their original positions far enough to flex the points sufiiciently to cause movement of the tips of the points, whereby the points are urged against the wheels of a trailing train with less force at their tips than at the point of connection of said means.

14. The combination with a switch of the type which is adapted to be trailed, of biasing means connected with said switch by connecting means and effective for constantly biasing said switch to a selected extreme position, said connecting means being so constructed and the parts being so proportioned that when a train trails the switch the biasing force due to said biasing means will decrease by an amount which depends upon the displacement of the switch from the selected extreme position, and means for retarding movement of the switch toward the selected extreme position by the biasing means when the switch has been moved away from the selected extreme position by a trailing train.

15. The combination with a switch of the type which is adapted to be trailed, of two separate biasing devices connected with the switch by separate connecting means in such manner that the one biasing device constantly biases the switch to a set extreme position and that the other biasing device constantly biases the switch to its nearest extreme position, the parts being so proportioned that the biasing force exerted by said other biasing device is always less than that exerted by said one device, whereby when a train trails the switch the resultant biasing force exerted on the switch by said two biasing devices decreases.

16. In combination, a railway switch of the type adapted to be trailed, operating means for moving the switch between its two extreme positions including biasing means for yieldably urging the switch to the extreme position to which it is moved, a resilient device located in the trackway, and linkage connecting said resilient device with said switch for applying force from said device to the switch in a direction to oppose the force of said biasing means when the switch is being trailed.

17. In combination, a railway switch of the type adapted to be trailed, a switch operating device movable between two extreme positions, resilient means for connecting said device with said switch in such manner that said switch will be biased to one position or the other according as said device is moved to its one extreme position or its other extreme position, a biasing device located in the trackway, and linkage connecting said biasing device with said switch in such manner that said switch is biased to its nearest extreme position by said biasing device.

18. In combination, a railway switch of the type adapted to be trailed, operating means for moving the switch between its two extreme positions including biasing means for yieldably urging the switch to the extreme position to which it is moved, a resilient device pivotally supported at one end in the trackway, and a bell crank lever pivotally supported in the trackway and having one arm operatively connected with said switch and the other arm operatively connected with the free end of said biasing device in such manner that said biasing device and said bell crank lever form a toggle which is effective to bias said switch to its nearest extreme position, the parts being so proportioned that the force which is exerted on said switch by said toggle at any time will be less than that which is exerted on said switch by said operating means.

HERBERT L. BONE.

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