US2515624A - Railway switch throw rod connection - Google Patents

Description

July 18, 1950 H. D. ABERNETHY RAILWAY SWITCH THROW ROD CONNECTION 2 Sheets-Sheet 1 Filed April 19, 1945 July 18, 1950 H. D. ABERNETHY RAILWAY SWITCH THROW ROD commqnou 2 Sheets-Sheet 2 Filed April 19, 1945 Patented July 18, 1950 RAILWAY SWITCH THR OW ROD CONNECTION Harry I). Abernathy, Lakewood, Ohio, ass ignor to General Railway Signal company, Rochester,

Application April 19, 1945, Serial No. 589,153

2 Claims.

This invention relates to the power operation of railroad track switches, and more particularly pertains to a yieldable switch throw rod connection.

In the usual power-driven switch machine for railroad track switches, of the type such as shown in the Patent No. 1,466,903 dated September 4, 1923, the throw rod operating the track switch from one extreme position to the other is actuated by cam action of a power-driven gear. This type of action produces tremendous forces on the throw bar particularly at the extremes of its movement, so that any slight displacement of the stock rails prematurely limiting the movement of the switch points may cause damage in the switch machine organization.

Also, the power operation of a track switch for railroads must be accompanied by a suitable lock rod mechanism and point detector organization, both of which must be adjusted to the desired limits so that any variation in the position of the switch points beyond such limits will prevent the closure of contacts and the unsafe clearance of signals to allow the passage of trafiic. However, it will be appreciated that such limits must allow for a reasonable variation on each side of a fixed position because of changes in temperature, ballast conditions, vibration, and the like.

In view of the above considerations, it is .proposed to provide a switch operating organization including a throw rod connectionwhich provides for the proper adjustment of the switch point operation between its extreme positions even though the switch machine is constructed for a standard amount of movement. At the same time, it is further proposed to provide this switch throw rod connection with a yieldable organization permitting only a limited pressure to be applied to the switch points within the limits of the allowable variation in the adjustment of the lock rods and the point detector mechanism.

A further object of this invention is to provide a switch throw rod connection which is readily adjustable, which is efficient and inexpensive to construct, and which provides the necessary freedom of movement of the throw rod connection under the various conditions ordinarily found in practice, together with means for reducing the amount of dirt, dust and moisture which would ordinarily gather upon the moving parts of such a yieldable throw rod connection.

Other objects, purposes and characteristic features of the present invention will be in part inpart pointed out as the description of the invention progresses.

In describing the invention in detail, reference will be made to the accompanying drawings, in which like reference characters designate corresponding parts throughout the several views, and in which:

Fig. 1 illustrates in a diagrammatic manner a railroad track switch and its associated power operating organization "constructed and arranged in accordance with the present invention;

Fig. 2 illustrates in detail a longitudinal view of the throw rod connection with certain parts in cross-section and constituting one form for use in the present invention;

Fig. 3 showsa cross-sectional view of the throw rod connection taken on lines 3-3 of Fig. 2; and

Fig. 4 shows a cross-sectional view of the throw rod connection taken on lines 44 of Fig. 2.

For the purposes of the present disclosure, the switch operating organization has been shown as including a power-operated switch machine such as that shown and described for example in the patent to W. K. I-Iowe Patent No. 1,466,903 dated September 4, 1923, which is adapted to have associatedtherewith a point detector mechanism such as disclosed in the patent to C. S. Bushnell Patent No. 1,517,236 dated November 25,1924; but it should'be understood that the invention may be used in connection with any suitable specific construction of switch machine and point detector organization by making the appropriate changes in the mechanical details involved.

Referring to Fig. 1 of the present disclosure, the stock rails of a railroad track switch Ts have been designated I, and the associated movable switch points have been designated 2; and for the purposes of the disclosure these movable switch points are shown in the turn-out position as their normal locked positions, but it should be understood that the switch points could 'be located in their main track position for the normal position, since the normal position assumed is merelyfor convenience in the illustration. Regardless of the particular normal position assumed, the switch points 2 of the track switch TS can be unlocked and operated to their reverse locked positions by the power-driven switch operating organization in a manner presently to be described.

The movable points 2 are inter-connected by the usual front rods 3 and 4. The =front rod 3 is connected by a plate 5 to the throw rod concbvious from the accompanying drawings, and 5:5 nector TRC, which is in turn connected through the throw rod TR to the throw bar TB of the switch machine. The throw bar TB is operated to its opposite positions by the main gear l8 which carries a driving pin 23 with a roller I! for engaging a U-shaped opening in the throw bar. This main gear I8 is operated through a suitable gearing organization which is power driven in both directions by a suitable motor M. This gear organization between the motor M and the main gear l8 includes a friction clutch K which is designed to allow operation of the motor M when the track switch TS becomes stalled in a mid position or near the end of its operation, in this way preventing damage to the motor and gearing organization. This friction clutch K also provides for an over-run protection for the motor at the end of an operation when the switch machine has locked the track switch, but the power is accidentally removed late from the motor by the control contacts. I

The free ends of the movable points 2 are connected by the front rod 4' which has a lock rod LR extendin to the locking bar 66. Associated with this look bar 66 is another look bar 61 which is adjustably attached to the bar 56 by a, suitable adjustable nut connection. While the switch points 2 are in normal positions as shown, the bars 66 and 6! are prevented from movement by the lock dog 55, but when the lock plunger LP is operated to the right during the unlocking operation performed by the roller 26 located on drive pin 23 on the main gear l8,

'the lock dog 56 is moved to the right allowing free movement of the lock bars 66 and 6?. When the switch points 2 have been moved to the new position by the throw bar TB through its throw rod TR and throw rod connector TRC, the lock dog 58 is again moved to the left to engage the bars 66 and 61 in their reverse positions, it being understood that there is a suitable slot for the dog 56 for the normal and reverse positions of the switch points, and that these slots are properly aligned by adjustment of the bar 66 with respect to the lock rod LR, and by the adjustment of the bar 61 with respect to the bar 66. This adjustment is so made with respect to the switch points 2 that the points may assume a position on either side of the proper position to only a limited extent such as one-sixteenth of an inch for example. If the movable points 2 are out of their normal or reverse positions more than this limited range, then the lock plunger LP cannot be moved to the left to its proper locking position because the lock bar 66 or B1 is out of alignment with the lock dog 56.

It should be noted that the throw bar TB cannot be moved from either extreme position until the lock plunger LP has been moved to the right because the lock dog acts to lock the throw bar TB when it is either a normal or a reverse position. The cam bars 59 on each side of the lock plunger LP act to center the contact shifting means CS by action through roller 93. The contact shifter CS is movedto its extreme positions by the action of the lock dog 56 on the lock plunger LP coming into contact with either the plunger 91 or 9-7 when plunger LP is being moved to the left. The contact shifter CS acts to move the contact block 19 to a mid position when the switch is unlocked and to a corresponding extreme position when the switch is again locked, but the contact block 6| associated with the pole changer is actuated from one extreme position to the other only at the end of the switch operation by reason of the arms 86 and 86a coming into contact with the arm 90 at the end of the corresponding operation of the switch machine. The contact block Si is also operated by the pole changercoils 63 and 64. These contacts associated with blocks 6! and 19 act to control the operation of the motor M by any suitable switch control circuit, one of which has been shown and described in connection with the switch machine disclosed in the above mentioned Patent No. 1,466,903, it being sufiicient to know for the purposes of this disclosure that these contacts act to deenergize the motor M at the completion of each operation, and by suitable circuits and auxiliary controls, may effect the reversal of the switch operation either in mid stroke or from either extreme position.

Extending from the lower movable point 2 is a point detector attachment rod 1 which is in turn connected to the detector rod DR to the detector bar ID. This detector bar [0 is adjustably connected to the detector rod DR and has associated therewith the detector bar ll adjustable thereto for the particular stroke of the switch points involved. The operation of the point detector mechanism through rod DR operates the movable contact block 53 as described in detail in the above mentioned Patent No. 1,517,236; but it is believed sufficient for an understanding of the present disclosure to know that this contact block 53 assumes as extreme position only when the movable switch points are in a corresponding normal or reverse extreme position, and assume an intermediate position Whenever the switch points are out of their extreme positions more than a limited amount, such as one-sixteenth of an inch for example, and also whenever the switch points 2 are unlocked by the lock plunger LP. As shown, the detector bars [2 and I3 are also associated with the point detector mechanism; and these additional bars may be used by connectin them to the other movable point 2, or may be omitted as desired. In some cases such a point detector contact mechanism is employed with a double-slip switch, or the like, and in such a case these additional bars I2 and I3 would be connected to the other portion of the double-slip switch.

With reference to Fig. 2 of the accompanying drawings, it will be seen that the throw bar connection TRC is connected to the front rod 3 through a suitable plate 5. This plate is attached to the front rod and the throw bar connections TRC by bolts held in place by suitable lock washers. The throw rod connector TRC includes a cylinder member 30 which has a flattened portion at the top as seen in Fig. 3 for attachment to, the plate 5. This cylinder member 30 has a cylindrical inner chamber within which there is inserted a spring 3| and two plunger members 32 and 33. The plungers 32 and 33 are held apart by a predetermined trapped pressure produced by the internal spring, and are held in a position onthe inside of the chamber by the end nuts 34 and 35. These end nuts, as can be seen in Fig. 4 with respect to nut 34, have inner contours for receiving a wrench. Thus, each end nut may be screwed into position against the machine surfaces at 36. With both of these end nuts 34 and 35 screwed into position, the plungers 32 and 33 assume their proper positions with a limited amount of separation at the center, such as one-quarter of an inch for example. Each of these plungers 32 and 33 is hollow exfer-a wet-"sea inner cross structurewith an 'Opehing' tl ildligh Whih the throw IOd TRcan pass, as best seen in- F'ig. 2; 0n the throw red are fsuitable thrust nuts 3-! and 38 which are positioned o'n't-he throw rod at proper points to allow free movement thereo fto the extent that the standard movement 'of'the switch machine exceeds the required movement of the switch points; but when the switch points are in a particular position, such as the normal position, as now shown for example, then the thrust nut 3'8 contacts theplunger t3 to holdthe connector THC an'd"switoh TS in pbsitibli, without causin tneinner "spring 3 I to be compressed. This means that so long as the switch points 2 remain in proper adjustment with res ect to the' switch 'machine'; and the stock rails I remain in their original set positions with respect to the switch machine, that the movement "of the switch to either extreme positionthr'ough the throw 'rod TR iseffectedfby a thrust pressure well below the predetermined pressure trapped within spring 3L by the end nuts. In other words, thespri'ng is riotfurther compressedundernormal operation, since the'tr'apped pressure" in spring '3'! is suffici'ent' to operate the switch points firmly against the-stockr'ails under theusual'operating conditions. V The thrust nuts-37 and 33 are providedwith hollow portions, as well as threaded portions so that they can be readily threaded 'over the full extent of the threads onthe throw rod into proper" positions as required. These thrust nuts 31 and 38 are then locked into position by their respective lock nuts 39 and 40. I it is noted that there is considerable free movement of thethr'ust nut'swithin the hollow opening of the plungers and the positioning nuts;

This is to allow for a certain amount of lateral motion of the throw rod TR during the passage of trains and the like over the switch points; However, the throw rod TB, is held in its position by reason of contactof the thrustnuts around their peripheries with the inner surface of their respective end nuts 34 and 35, it being understood that the extent of adjustment of the lost motion connection should not be beyond the extent or theinner surfaces of the end'n'uts. At the outer ends of the enclosed cylinder are suitable "dirt barrier bushings M and 42, made of any suitable materialsuch as fiber, felt, or metal if desired, which bushings have inner openings fairly closely conforming to the outer periphery size of the thrust nuts 31 and 38; and these dirt barriers 41' and 42 are 'slidably positioned over the ends of the chamber by the lateral movement of the throw rod TR since they are rather loosely fitted beneath their respective covers 43 and 4-1 which are held in position by the stud bolts 45 (only one of which is seen) and the bent arms Atas best seen in Figs. 3 and 4. In this connection it will be noted that the enlarged portions-oi the end lock nuts 34 and 35 which permit the insertion of a socket wrench in the mam assembly of the mechanism, also acts as r a dust receiving chamber so that the dust or dirt may fall out of position with respect to the inner bearing surface upon which the thrust nutsride. With this organization, it is readily apparent that 'difierent bearing surfaces may be lubricated and yet protected from the formation of dirt and dust deposits.

Referring to Fig. '1, it is desired 'tcpoiht out thatthedriving of the 'thr'owbar TB is by a cam action 'whichof ccurs'eue'v'eicps a greater thrust on the switch poirits iwhen "theswitch points are being moved nearthend of their operation. For example, some switch machines will develop 'as high as four thousand pounds of ressure on the switch points in mid stroke which-may raise to five or six thousandfpounds near-the end of the stroke. If the switch points 2 and'the stock rails I remain in their proper positions withriespect to the switch machine, the points may be moved to their opposite extreme positions with a relatively small thrust on the throw rod TR, which thrust need be just sufficient to overcome the friction developed and the' final locking up operations of the points. This normal operation may require four to five hundred pounds thrust on the switch points depending upon conditions encountered andthe size of the rails employed.

Referring to the throw rod cohnector'TR'C, the biasing spring tl is compressed between the plungers 32 and 33 to provide a trapped pressure well above thatthrust required for the normal operation of the switch points. ihis trapped pressure may be in the order of two thousand pounds for example. When such a trapped pressure is used, then the spring 31 will have such characteristics that the further compression of the spring to the extent or the one-quarter of an inch allowable movement by reason ofthe space between the plungers 32 and 33 will cause the pressure on the plungers to be increased, as for example, to twenty-four hundred pounds. It will be thus seenthat under normal operation the throw rod TR will act through the thrust nuts 31 and 38 to move the switch points 2 to their opposite positions without causing any further compression of the spring 3| due to its initial trapped pressure.

As noted above, there must of necessity be certain allowable variations in the positions of the switch points, such as for example one-sixteenth of an inch on either side of the initially set position; and in the event that there is a displacement of the stock rails to the extent of the al- Io'wed variation, it may happen in moving the switch points to an extreme position that, without the yieldable throw rod connector provided by the present invention,'the extremely high thrust above noted as developed by the switch machine in its final movement, will be produced on the switch points. Since the lockbars and detector bars are adjusted to allow such permissible deviation, then it may be that the high thrust pressures on the switch points will continue to be developed at the end of each opera- .tion of the switch points, which in the course of time would be detrimental to the structure of the switch machine including the throw rod, throw bar, and gearing mechanisms. However, the present invention provides that the variation of a sixteenth of an inch either way will becompensated for by the thrust of the throw rbd TR, being applied against the plunger 32 or 33, as the case may be, causing its movement and compression of the spring 3| instead of actually forcing the switch points and. the stock rail. Since the complete compression of the spring throughout the one-quarter inch allowable compression will under the example assumed not exceed twenty-four hundred pounds, then in spite of the cam operation of the throw bar, this amount will not be exceeded even though the switch points and stock rails have deviated from Eheir central set positions to the allowable ex- It should be noted, however, thatv should the allowable variation in position of the switch points be exceeded, or should snow, ice, coal or the like be blocking the switch points, the entire thrust of the switch machine will be exerted on the switch points by first acting to compress the spring 3! through movement of the plunger for the one-quarter inch movement, and then applying the full power to the switch machine against the switch points. This organization assures protection for the switch machine under normal variations in load and position, and yetprovides the full application of the switch machine power under emergency conditions to assure that the switch will be freed from any obstructions and operated to a full normal or reverse locked position as the case may be.

In connection with the allowable variation in the movement of the switch points, it should be pointed out that the excessive thrust of a switch machine on the switch points even through the extent of the allowable variation in the displacement of the stock rails, may result in the warping or bending of the switch points in such a way as to cause the points to be slightly opened although the lock rods, detector rods and throw rod are in their extreme positions. This contingency is obviated by the present invention, since the maximum pressure that can be applied under normal operations is that which the spring 3| will allow, and cannot exceed the complete compression pressure of such spring.

In practice, it is customary to test power operated switches periodically to see whether the switch is being operated to normal and reverse positions within the allowable range of variations with respect to the stock rails. This is usually done by placing a standard thickness obstruction between the points and the stock rails which is expected to prevent the locking operation of the switch machine. For example, if the switch points are in their normal positions, and an obstruction, such as a metal bar of one fourth inch thickness is placed against the stock rails in the reverse position followed by the operation of the switch machine to its reverse position, the switch machine should fail to lock the switch points by lock dog 56, because the obstruction is greater than the allowable variation, such as one sixteenth of an inch. It is apparent that these periodical tests would cause extreme pressures on the throw bar and switch points regardless of whether the operation of the switch machine under such test conditions is by hand or by power. The use of the present invention prevents these extreme pressures on the throw bar and switch points by reason or the yieldability of the throw rod connector TRC to an extent comparable with such standard tests, thus obviating any possible bending or misplacement of the points, or breakage with respect to the throw bar, as well as obviating undesired displacement of the stock rails due to the application of extreme pressures under such testing operations.

It will thus be seen that a practicable switch operating organization is provided in which a switch machine is connected to its associated switch points by a throw rod connection that is yieldable within pre-determined limits to provide protection from extreme pressures under conditions of allowable variation in the positions of the rails, and also under arbitrary test conditions.

It is to be understood that the quantities sue.

gested herein by way of example, have been given merely as illustrations of one practical embodiment, it being understood that conditions of practice may require that difierent quantities be employed, all of which is believed to be within the scope of the present invention.

Having described a switch operating organization as one specific embodiment of the present invention, it is desired to be understood that this form is selectedtofacilitate in the disclosure of the invention rather than to limit the number of forms which it may assume; and, it is to be further understood that various modifications, adaptions and alterations may be applied to the specific form shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention except as limited by the appended claims.

What I claim is:

1. In a connection between a power operated switch machine having a stroke of operation of a fixed distance and the points of a railroad track switch requiring a stroke of some lesser distance, a casing attached between the points of said switch and having a cylindrical chamber, two plungers slidably located within said chamber and being sufiiciently long to extend substantially throughout the length of the chamber except for a limited space between said plungers, each of said plungers being hollow for a portion of its length on its inner end adjacent the other plunger, two abutment nuts one at each end of said casing threaded thereto to provide the two outer limits of movement of said plungers within said cylindrical chamber, a single coil spring located between said two plungers and within their respective hollow portions for forcing them outwardly against their outer limits provided by said abutment nuts with an initial thrust somewhat less than is provided by said switch machine, a'throw rod connected to said switch machine and freely passing through the plungers, spring and abutment nuts, and two adjustable thrust members on said throw rod, one on each side of said casing and each for engaging its respective plunger for acting against the compression or said coil spring, said thrust members being so spaced apart as to allow free relative movement of the throw rod in accordance with the excess of the operating stroke of said switch machine over that required for said switch points, but engaging their respective plungers to cause operation of said switch points to a normal or reverse position in accordance with a thrust not greater than the thrust of said coil spring under usual circumstances but with the entire thrust of said switch machine being applied if said coil spring is compressed until one plunger has moved through said limited space and contacts the other plunger.

2. In a connection between a power operated switch machine having a stroke of operation of a fixed distance and the points of a railroad track switch requiring a stroke of some lesser distance, a casing attached between the points of said switch and having a cylindrical chamber, two plungers slidablylocated within said chamber and being sufliciently long to extend substantially throughout the length of the chamber except for a limited space between said plunger, each of said plungers being hollow for a portion of its length on its inner end adjacent the other plunger, two abutment nuts one at each end of said casing threaded thereto to provide the two outer limits of movement of said plungers within said cylindrical chamber, a single coil spring located between said two plungers and within their respective hollow portions for forcing them outwardly against their outer limits provided by said abutment nuts with an initial thrust somewhat less than is provided by said switch machine, a throw rod connected to said switch machine and freely passing through the plungers spring and abutment nuts, two adjustable thrust members on said throw rod, one on each side of said casing and each for engaging its respective plunger for acting against the compression of said coil spring, said thrust members being so spaced apart as to allow free relative movement of the throw rod in accordance with the excess of the operating stroke of said switch machine over that required for said switch points, but engaging their respective plungers to cause operation of said switch points to a normal or reverse position in accordance with a thrust not greater than the thrust of said coil spring under usual circumstances but with the entire thrust of said switch machine being applied if said coil spring is compressed until one plunger REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,976,828 McWhirter Oct. 16, 1934 2,007,674 Bone July 9, 1935 2,022,253 Nortz Nov. 26, 1935 2,064,891 Egen Dec. 22, 1936 2,175,593 Bone "Oct. 10, 1939 2,309,252 McGowan Jan. 26, 1943 2,341,718 Howe Feb. 15, 1944 2,401,294 Clymer et al June 4, 1946

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