US3099427A

US3099427A - Railway switch point bearings

Info

Publication number: US3099427A
Application number: US713871A
Authority: US
Inventors: Ned C L Brown
Original assignee: General Signal Corp
Current assignee: SPX Corp
Priority date: 1958-02-07
Filing date: 1958-02-07
Publication date: 1963-07-30
Anticipated expiration: 1980-07-30

Description

July 30, 1963 N. c. L. BROWN 3,099,427

7 RAILWAY SWITCH POINT BEARINGS Filed Feb. 7, 1958 5 Sheets-Sheet 1 INVENTOR.

N.C.L .BROWN HIS ATTORNEY July 30, 1963 N. c. L. BROWN RAILWAY SWITCH POINT BEARINGS 3 Sheets-Sheet 2 Filed Feb. 7, 1958 I-luuu INVENTOR. N C. L B ROWN )LMMJ HIS ATTORNEY July 30, 1963 N. c. L. BROWN 3,099,427

RAILWAY SWITCH POINT BEARINGS 5 Sheets-Sheet 3 FIGS. 8 l

Filed Feb. 7, 1958 IIIIIIIIJ 'IA III;

INVENTOR.

7 42 N.C.L.BROWN I BY i lmw Hl ATTORNEY United States Patent 3,tl99,427 RAILWAY SWiTCl-ll PGlNT BEARINGS Ned C. L. Brown, Scottsville, N.Y., assignor to General Signal Corporation, a corporation of New York Filed Feb. 7, 1958, Ser. No. 713,871 9 Claims. (til. 246-435) This invention relates to railway switch point operation, and more particularly relates to a structure for reduoing friction during the movement of the switch points from one switch position to another.

Modern day railroading which requires higher speed movement of trains on single track lines having various passing sidings calls for switching movements which must be made quickly and positively as many of these passing train movements are made with both trains in motion. Also, as a general rule, such switches are made longer to reduce as much as possible the curvature encountered by the train in passing over the switch. Furthermore, due to heavier rolling stock, the tendency has been to use heavier rails. Such type of switches naturally results in more bulk and weight to be moved by the switch operating mechansm.

In standard railway switch construct-ion, the switch points each comprise a modified single rail which is suitably fastened at its heel end to a stock rail by means of a heel block which acts as a pivotal point to permit movement of the leading end of the switch point to an open or closed position. The amount of movement is determined by the throw of the switch operating mechanism and is usually approximately five inches at the leading end to allow adequate wheel flange clearance at the open switch point. ese switch points are spaced apart and tied together by means of a series of spaced switch rods extending between the switch point rails so that they move in unison. When one switch point is closed and bearing against its associated main or stock rail, the other switch point is open and spaced its maximum distance from the other main or stock rail.

The main rails are secured to and rest upon tie plates secured to the ties which are part of the railway roadbed; whereas, the switch point rails for the most part merely rest on the tie plates and are slidably movable thereon. The leading ends of the switch point rails have their base portion partially cut away on a taper so that in a close-d position they rest on the base portion of their associated main rail rather than on the tie plates. This construction provides a tendency for the switch point rail in its closing motion to lift free from the tie plates and permit a close snug contact with its associated main rail. The switch rods, which tie the switch points together, are constructed long enough to extend under the main rails at both ends with a suitable clearance therebetween so that any undue tendency of the switch points to lift is arrested at the limit of the clearance provided.

It can thus be understood that the entire weight of the switch point rails and their associated fittings bear on the tie plates and partially on the base of a main rail at all times and considerable sliding friction is present during the movement of the track switch from one position to the other. Greasing or oiling the bearing surfaces may alleviate this condition to some extent, but the accumulation of dirt, sand and other foreign substances which mixes with the lubricating agent can actually increase the amount of friction. Also, as all parts of the track switch are at rest when the switch movement is started, there is considerable static friction present which must be overcome by the starting effort.

Another factor which tends to produce additional sliding friction and work against the operating force is the fact that the distribution of the weight of the switch points to the various tie plates may become very uneven due to poor tamping of the ballast supporting the ties. This may bring about a situation wherein a particular tie plate is supporting more than its share of the Weight. If such a situation existed particularly near the longitudinal center of the switch point rail, the friction might be so great that an attempt to throw the switch points from from one position to another might actually result in a distortion or bending of the rail between the point of extreme friction and the leading end of the rail. Otherfrictional resistance is also inevitably present at the heel block ends of the switch point rails,v because at this point the switch point rails are usually fastened to the stationary rails and there is a possibility that the switch point rails are actually forced down against their supporting tie plates.

With the above frictional problems in mind, the present invention proposes a means whereby the movable switch point rails are supported on needle or roller hear-- ing structures which in turn are each supported on an arched leaf spring which rests on a tie of the railroad roadbed. This arrangement resiliently positions theswitch point rails slightly above the tie plates on the tiesof the railroad roadbed under normal conditions so that when a switch movement is made the switch point rails are carried by the needle or roller bearing structures rather than sliding on the tie plates.

In some installations where long track switches are used it is proposed to mount two supporting needle bearing structures under each switch point rail, one a few feet back from its leading end preferably near the number two switch rod and another about midway along its length preferably near the number four switch rod. In other installations where shorter track switches are used, it will only require one supporting needle bearing structure under each switch point rail, preferably located near the leading end of the switch.

Each supporting needle bearing structure comprises in general a moisture proof housing for the needle bearings which comprises a lower base portion which retains the needle bearings and provides a bearing surface on which they roll, and an upper cap or cover portion which encloses the needle bearings and bears thereon. The base portion is suitably fastened to a tie plate on a tie of the railroad roadbed with an arched leaf spring interposed therebetween in a manner whereby the leaf spring is permitted to flex and the base portion is permitted vertical movement. The cap portion resting on the needle bearings is subject to horizontal movement and provides a bearing surface for the switch point rail.

The switch point rail has a bracket member attached thereto, this bracket member having an outwardly extending supporting lug formed integral therewith. This supporting l-ugis provided with an inverted cup shaped bearing surface which is formed to receive a ball like bearing surface formed on the topof the cover of the needle bearing structure.

This structure provides a means whereby each switch point rail is supported throughout the greater part of its:- length on needle bearing structures which in turn aresupported on arched leaf springs. The upward bias of the leaf springs is suflicient to support the weight of the switch points and maintain a clearance between the base of the switch point rails and the tie plates. Thus, during a switch movement, the weight of the switch points is carried by the needle bearing structures and sliding friction is limited to the extent of that produced by the needle bearing structures and the heel end of the switch which of necessity must bear on the tie plates. Also, when a train is passing over the switch, its weight will force the closed switch rail downward against the bias of the leaf spring so that the switch point rail may again hear on the tie plates. Therefore, the needle hearing structures never have to carry the weight of the train and merely serve to facilitate switch movements.

As previously mentioned, the switch rods extend under the main rails and have a slight clearance therebetween, the purpose of which is to hold the switch point rails down within the clearance limitations and yet prevent any excess lifting thereof. However, track switches equipped with a means for resiliently supporting the switch point rails above the tie plates as proposed hereinbefore, would also cause the switch rods to be lifted so that they would rub on the underside of the main stock rails during a switch movement. Also, poor adjustments or poor ballast tamping may bring about a situation wherein the switch rods would bear against the underside of the main stock rails. The present invention proposes a means whereby such friction caused thereby during a switch movement may also be eliminated.

This proposed means for limiting upward movement, and yet preventing switch rod friction comprises another needle bearing structure, one of which is placed on each end of the number two and number four switch rods and adjacent to the switch point rail needle bearing supports previously mentioned. These needle bearing limit structures are positioned directly under the main stock rails and are attached thereto by means which permits vertical movement thereof. Their structure is such that the needle bearings are situated between the top surface of the switch rod and the bottom surface of an upper bearing plate. When the switch rods are in their extreme upward positions, such as when the switch points are resiliently suspended as previously explained, the tops of the upper bearing plates bear against the bottom of the main stock rails and the switch rods bear against the needle bearings. 'I hus, switch movement may be accomplished with the switch rods moving horizontally over the needle bearings rat-her than rubbing against the bottom of the main rails.

In a second formof the present invention, it is proposed to utilize the switch rods to resiliently support the switch point rails on needle bearing structures to facilitate switch movements. In this form of the invention, the switch rods, which are normally attached to the switch point rails by means of switch lugs, are themselves supported at each end on needle bearing structures. In efiect, the switch rods of this proposed structure normally support the switch point rails rather than having the switch point rails support the switch rods.

The supporting needle bearing structures each comprise a housing having a bearing plate base portion which contains the needle bearings. The end of the switch rod passes through the housing and is positioned so that its flat bottom surface bears on the needle bearings. These needle bearing structures are each supported by a bridge member which is located between and fastened to two adjacent ties of the railroad roadbed. The bridge member is provided with a raised arcuate bearing surface which is received by a depressed arcuate bearing surface formed on the underside of the base portion of the needle hearing structure, thus providing a rocker type bearing support for the needle bearing structures.

The location of the bridge members on the railroad ties is such that the switch rods are positioned to support the switch point rails a slight distance above the ballast of the railroad roadbed under normal conditions. Thus, during a switch movement, the switch rods and the major portion of the switch point rails are carried on the needle bearings and sliding friction between the switch point rails and their supports is at a minimum. However, during the presence of a train on the closed switch point rail, the added weight of the train will depress the switch point rail and cause the switch rods to flex and give to the extent that the switch point rail will bear on the stock or main rail and the associated tie plates. This flexing or arching of the switch rods permits the weight of the train to be borne by the rails themselves rather than by the needle bearing structures. Furthermore, as the needle bearing structures at each end of the switch rod are mounted on rocker type bearing surfaces, they merely rotate to change their plane to correspond to that of the end portions of the switch rods.

The switch rods in this second form of the invention are also provided with additional needle bearing limit structures located under the main stock rails in a manner similar to those provided in the first form of the invention. As previously mentioned, these additional needle bearing structures provide a hold down means for the switch structure yet eliminate all sliding friction between the switch rods and the underside of the main stock rails.

Other objects, purposes and characteristic features of the present invention will be in part apparent from the accompanying drawings and in part pointed out as the detail description of the invention progresses.

In describing the invention in detail, reference will be made to the accompanying drawings which show various views, some with parts in the background eliminated for clearness, and in which the different parts are referred to by distinctive reference characters and like parts by like reference characters, and in which:

FIG. 1 is a top plan view of a conventional switch layout and shows the needle bearing supporting structures of the present invention applied thereto;

FIG. 2 is an end sectional view taken substantially on the line 2-2 of FIG. 1 and shows a typical switch rod mounted to the switch point rails with the switch operating rod attached thereto, all reference to the needle hearing supporting structures of the present invention being omitted for clearn'ess;

FIG. 3 is an end sectional view taken substantially on the line 33 of FIG. 1 and shows the needle bearing supporting structures of the present invention as applied to the switch point rails;

FIG. 4 is an enlarged sectional view of the closed switch point portion of FIG. 3 and shown more in detail and section as taken on the line 44 of FIG. 6;

FIG. 5 is a view similar to FIG. 4 except that it shows the switch point rail in a forced down seated position due to the presence of a car wheel thereon;

FIG. 6 is an enlarged side elevation view of the needle bearing support and switch apparatus shown in FIGS. 1, 3, and 4 and is shown partly in section as indicated by the line 66 of FIG. 1;

FIG. 7 is an end section view taken substantially on the line 77 of FIG. 1 and shows one of the standard switch tie rods with the additional non-friction hold down needle bearing structures of the present invention applied thereto;

FIG. 8 is an enlarged sectional View of the closed switch point portion of FIG. 7 and shown more in detail and section as taken on the line 88 of FIG. 9; FIG. 9 is a side elevation view of the apparatus shown in FIGS. 1 and 8 and is shown partly in section as indicated by the line 99 of FIG. 1;

FIG. $10 is an end section view similar to FIG. 7 and shows the modified form of the present invention wherein the standard switch tie rod is provided with needle bearing structures and supporting means therefor for supporting the switch point rails in a suspended position;

FIG. 11 is an enlarged sectional view of the closed switch point portion of FIG. 10 and shown more in detail and section as taken on the line 11I1 of FIG. 12;

FIG. 12 is a side elevation view of the apparatus shown in FIG. 11 and is shown partly in section as indicated by the line 12-42 of FIG. 11; and

FIG. 13 is a top plan view of the apparatus shown in FIGS. 11 and 12 and is shown partly broken away and partly in section 1213 indicated by the line 13-13 of FIG. 11.

Referring now to the drawings, and more particularly to FIGS. 1 and 2, in order to illustrate the present invention applied thereto, there has been shown (partially omitted by broken lines) a typical long switch layout as would normally be used for high speed trains, such as one approximately thirty feet long. The switch layout in general comprises the two main stock rails l and 2 which rest upon tie plates 3 mounted on ties 4 forming the track roadbed. The

rails

1 and 2 are secured to the ties by means of the usual spikes and rail braces. Located between the two main stock rails '1 and 2 are the two movable

switch point rails

5 and 6 which are hingedly connected to the two stationary switch rails 7 and 8 by means of heel blocks 9. This type of connection is standard practice and no attempt will be made herein to show or describe the details. As shown in FIG. 1, the

switch point rails

5 and 6 are movable back and forth on their supporting structures to the extent of the switch point adjustment applied to their leading ends. The amount of this movement must be suflicient to permit clearance for the wheel flanges and correspond to the throw of the switch throwing device (not shown). Suitable tie bars 10 extending the length of the switch are fastened to the ends of the ties 4 to maintain proper spacing between them.

The

switch point rails

5 and 6 are spaced apart and tied together by means of a series of switch rods comrnonly known as the No. 1, 2, 3 and 4 rods and have been designated on the drawings as 11, 12, 13 and 14. The purpose of these switch rods which are spaced throughout the front half length of the

switch point rails

5 and 6 is to maintain the switch points in a properly spaced relationship to each other and hold them rigidly upright. These switch

rods

11, 12, 13 and 14- also extend underneath the

main stock rails

1 and 2 with a slight clearance therebetween and normally :act to prevent any undue lifting of the

switch point rails

5 and 6.

The No. 1 rod or switch rod 11 is of special construction and is also used for receiving the switch operating rod 15 which serves as the connection between the switch points and the switch operating mechanism (not shown). This switch rod 11 is mounted near the leading ends of the switch points in a vertical position for strength and rigidity purposes, and is adjustably attached to the

switch point rails

5 and 6 by means of adjustable brackets havingextra long vertical bearings 16 as shown in FIG. 2. As is well known in railway switch construction, the leading ends of the

switch point rails

5 and 6 are of necessity very thin in width, and this special construction is necessary to maintain them in their upright positions so that bending, tilting and so called rolling is prevented. For a detailed showing and description of this special construction reference may be made to the E. C. Larry US. Patent No. 2,584,719 dated February 5, 1952 The track switch is also provided with a front rod 17 at its very tips for added rigidity for the

switch point rails

5 and 6. This front rod 17 is constructed similar to the switch rod 11 and may be connected by a rod '18 to a suitable point detector (not shown) for indicating the fact that the switch points are in their extreme operated positions. The

switch rods

12, 13 land 14 are usually mounted in a horizontal position as their main function is to space and hold the

switch point rails

5 and 6 in a related position. is connected to a locking device (not shown) which locks the switch in its last operated position.

Suitable spacing blocks or clips 19' are mounted on the web section of the

switch point rails

5 and 6 by means of bolts or the like and are located at spaced intervals between the switch point rails and their associated

stock rails

1 and 2 throughout the heel end half of the switch assembly. These spacing blocks are of selected widths so that they fill the space between the webs of the switch point rail and the stock rail with the switch point in a closed position, this space getting greater as the heel end of the switch is approached. It can be seen that the In some instances, the switch rod 12 individual closed switch point rail no longer contacts its associated stock rail throughout the heel end half of the switch. The spacing blocks 19 are provided so that the switch point rail may still bear against its associated stock rail and thus prevent spreading and possible deformation of the switch point rail caused by the train passing therethrough.

'Reference is now made to the needle bearing supports of the present invention as proposed for alleviating friction between the base of the switch point rails and the tie plates during a switch movement. For a long switch such as shown on FIG. 1 of the drawing, it is contemplated that such a support be mounted under each

switch point rail

5 and 6 near the leading end of the switch and also near the midway lengthwise section of the'switch. With reference to FIG. 1, two such supports designated S1 are shown mounted on a tie '4 adjacent and to the rear of the switch rod 12, and two other such supports designated S2 are shown similarly mounted adjacent and to the rear of the switch rod 14.

With particular reference to the mounting of the two needle bearing supports S1 illustrated in FIG. 3, the tie 4 is notched or cut away as shown at 21 to provide a clearance under the switch point rails so that the needle bearing supports may be mounted on the tie. Chair supports '22 which are also mounted on the tie 4 by means of bolts 23 provide :a support for the

main stock rails

1 and 2 at the same level as the other ties and also maintains the spacing between the rails and the tie constant. The usual rail braces 24 are employed to hold the rails .1 and 2 in position on the chair supports. The cut away portions 21 of the tie 4 are provided with steel tie plates 25 which provide a stable supporting surface for the chairs 22 and the needle bearing supports S1.

With reference now to the enlarged detail views FIGS. 4 to 6 inc., each needle bearing support comprises a base plate 26 and a top plate 27 between which lie the needle bearings 28. The base plate 26 rests on an arched leaf spring 29, and both are mounted on the tie plate 25 by means of bolts 30. These bolts 30 are suitably anchored in the tie plate 25 such as by welding or the like, and have their shanks extending upward through holes in the leaf spring 29 and the base plate 26. The leaf spring 29 is provided with elongated holes 31 to permit horizontal movement, whereas the base plate 26 is provided with enlarged holes 32 to permit vertical movement on the bolts 30. The bolts 30 are provided with threadsand nuts 33 to adjustably secure the base plate at the proper; height as will be explained hereinafter.

The needle bearings 28 are contained in a. recessed bearing race 34 formed in the top surface of the base plate 26. The top plate 27 bears on the needle bearings 28 and is mounted in a manner to provide for horizontal. movement thereon. Suitable gasket packing material 35, is provided between the base plate 26 and the top plate 27 to seal the lubricant within the bearing race 34 and keep the moisture out.

The switch point rail 5, which has been chosen for the purpose of illustration, is supported on its associated; needle bearing support S1 by means of a bracket plate 36. This bracket plate 36 is secured to the web of the switch point rail 5 by means of the bolts 37. Suitable shim or reinforcement plates 38 are inserted on both sides of the rail Web to strengthen the switch point, .and' in this case serve to facilitate proper alignment of bracket: plate 36. A cup shaped. lug or socket bracket 39' is' formed integral with the bracket plate 36 and extends at substantially a right angle thereto. The underside of the lug 39 is provided with an inverted rounded socket to receive a rounded head 40 which is formed on the top sur face of the top plate 27, thus providing a ball like bearing which permits rotary motion between the switch point rail 5 and its associated needle bearing support S1.

It can now be seen that the switch point rail 5 is resiliently supported above the roadbed by the leaf spring 7 29 through the medium of the bracket plate 36 and the needle bearing support 51, and that the switch point rail is carried by the needle bearings 28 during a switch movement from one position to another. As previously mentioned, the bias of the arched leaf spring 29' is normally a little more than is required to carry the weight of the switch point rail .and its associated parts. In assembly, the nuts 33 are tightened down against the base plate 26 until the desired clearance is obtained between the bottom of the switch point rail and its associated roadbed structure consisting of the tie plates and the foot of the main stock rail. This procedure also places the leaf spring 22 under compression and the pressure created thereby stabilizes the horizontal position of the base plate 26. The nuts 33 may be locked in position on the bolts 30" by cotter pins or the like to maintain the adjusted position.

The needle bearing supports S2 located under the

switch point rails

5 and 6 at or near the middle lengthwise portion of the switch are constructed similar to the supports S1 described above. However, the clearance provided between the bottom of the switch point rails and the associated tie plates would probably be less and the nuts 33 would have to be tightened down accordingly to further compress the leaf spring 29 and lower the position of the base plate 26.

With the major portions of the

switch point rails

5 and 6 supported on needle bearing structures as described, normal movements of the switch points may be accomplished with the weight of the switch points and their associated parts being carried on the needle bearings 28, thus reducing actual contacting friction to a minimum. However, it is not intended that the needle bearings should carry the weight of a train. Thus, when a train is present and passing over the switch as indicated by the car wheel CW in FIG. 5, the weight of the train merely forces the closed switch point rail 5 downward against the bias of the arched leaf spring 29 until the switch point rail bears on the foot of the main stock rail 1 and partially on the tie plate 3. (See FIG. 2.) In this position, the weight of the train is borne by the rails in the usual manner during its passage through the switch. The bias of the leaf spring 29 will again raise the switch point rail 5 above the tie plates after passage of the train, so that the switch is restored for normal operation.

Referring now to the needle bearing structures of the present invention as proposed for alleviating friction between the base of the main stock rails and the top of the switch rods during a switch movement, as previously men- \tioned, it is contemplated that such needle bearing structures be mounted on both of the

switch rods

12 and 14. As shown in FIGS. 1 and 7, these needle bearing structures designated S3 are mounted on the

switch rods

12 and 14 at positions directly under the

main stock rails

1 and 2 and at locations adjacent to the needle bearing supports S1 and S2 previously described.

With particular reference now to the enlarged detail views FIGS. 6, 7, 8 and 9 which illustrate the apparatus in conection with the switch rod 12, each needle bearing structure S3 comprises a housing having a rectangular opening in each end through which the switch rod 12 may pass. This housing consists of a channel shaped top plate 45 and a flat bottom plate 46 which are suitably fastened together as by bolts 47. The top plate 45 1s provided with a recessed bearing race 48 in its bottom surface to retain the needle bearings 49. Thus, the needle bearings 49 are positioned between the top plate t5 and the switch rod 12.

As shown in FIG. 8, the complete needle bearing structure S3 is maintained in position under the main stock rail 1 by an anchoring means which permits vertical movement but not horizontal movement. This anchoring means consists of an upwardly extending lug 56 formed integral with the top plate 45 which extends through an opening 51 in an angle bracket 52. The angle bracket 52 is securely fastened to the web of the main rail 1 by means of bolt 53. The top plate 45 is also provided with a rounded boss 54 which serves as a contact point between the bottom of the main rail 1 and the needle bearing structure S3. Suitable gasket packing material 55 is provided between the top plate 45 and the switch rod 12 to seal the lubricant within the bearing race 48 and keep the moisture out.

In actual practice, the switch rod 12 is fastened to the

switch point rails

5 and 6 by means of .a switch log 56 which is secured to the web of the switch point rail by means of the bolts 37. The lower jaw portion 58 of the switch lug 56 is pivotally connected to the switch rod 12 by means of a bolt 59. Thus, the switch rod 12 is subject to vertical and horizontal movement in accordance with the movement of the

switch point rails

5 and 6.

The switch rod 14 is mounted in a manner similar to the switch rod 12 and is also provided with needle hearing structures S3 which are mounted in a manner similar to those explained in connection with the switch rod 12.

It will now be understood that with the

switch point rails

5 and 6 supported in their normally raised positions by means of the resilient supporting means S1 and S2 previously described, the switch rods 12 .and 14 will also be in a raised position so that their associated needle bearing structures S3 will be hearing against the bottom of the

main stock rails

1 and 2. However, even though the top plates 45 (see FIGS. 8 and 9) are bearing against the bottom of the

main rails

1 and 2, the switch rods themselves are bearing against their respective needle bearings 49. Thus, the upward thrust of the

switch rods

12 and 14 is against the needle bearings 49 and the top plates 45 merely act as stops or limits for the upward movement. During a switch movement, as the

switch rods

12 and 14 move horizontally over the needle bearings 4 9, fricdon would be reduced to a minimum.

As previously mentioned, when a train is present on the track switch, the closed switch point rail would be depressed, thus forcing it down to rest on the tie plates. This downward movement of the closed switch point rail would cause a downward movement of those particular ends of the

switch rods

12 and 14. Likewise, their associated needle bearing structures S3 would move downward away from the bottom of the main stock rail and their vertical motion would be guided by reason of the movement of the upwardly extending lug 50 through the opening 51 in the angle bracket 52. As the switch point rails are normally resiliently supported in their upward positions, the switch rods and all associated parts will return to a normal raised biased position after passage of the train.

in a modified form of the present invention as illustrated in FIGS. 1013 inc., the switch rods are mounted on needle bearing structures S4 which are located at each end thereof and supported on bridge members B which are fastened to the ties 4 of the railroad roadbed. The

switch point rails

5 and 6 are connected to the switch rods by means of the usual switch lugs 56 and

bolts

57 and 59. The location of the bridge members B is such that the switch rods normally support the

switch point rails

5 and 6 slightly above the tie plates 3 of the railroad roadbed. The switch rods are also provided with needle bearing structures S5 which are similar to the needle bearing structures S3 previously described for the purpose of providing a hold down means for the track switch which reduces sliding friction to a minimum. It is contemplated that only the

switch rods

12 and 14 be equipped with this supporting means as these rods are located near the leading end and center section of the track switch but it should be obvious that other switch rods, such as 13, could be similarly equipped if additional supper-ting means is found necessary.

For the purpose of illustration, the supporting means has been shown as applied to the switch rod 12 as shown in FIG. 10, and for an enlarged detailed showing reference should be made to FIGS. 11, 12, and 3 wherein the closed switch point end of the track switch has been shown in conjunction with the supporting means for the associated end of the switch rod 12. The bridge member B consists of a U shaped member having end portions 65 which rest on the tie plates 3 of two adjacent spaced ties 4 and having an offset center portion 66 which extends downward between the two adjacent ties 4-. The base of the center portion 66 of the bridge member B is provided with a bearing member 67 which is suitably fastened thereto as by welding or the like, for supporting the needle bearing structure S4. The bridge members B are secured to the ties 4 by means of lag screws 68. Suitable shims 69 may be inserted between the bridge member B and the tie plates 3 to adjust the height of the bearing member 67 which may vary due to ballast conditions.

The needle bearing structure S4 consists of a housing having rectangular openings in each end through which the switch rod 12 may pass. This housing has a channel shaped base plate 70 and a fiat top plate 71 which are bolted together by means of bolts 72. The base plate is provided with a bearing race 73 which contains needle bearings 74. These needle bearings 74 form a bearing surface for the switch rod 12 when it is passed through the housing. Suitable gasket packing material 75 is provided between the base plate 7% and the switch rod 12 to seal the lubricant within the bearing race 7 3 and keep the moisture out. The base plate 70 is also provided with a depressed arcuate shaped bearing surface 76 on its bottom side to receive the arcuate shaped raised bearing surface 77 formed on the top side of the bearing member 67, thus forming a rocker type bearing support for the needle bearing structure S4.

The needle bearing structure S is the same as the needle bearing structure S3 used in the first form of the invention and described in detail in connection with FIG. 8, and will be referred to by like reference characters. As previously mentioned, this needle bearing structure S5 is mounted on the switch rod '12 and limits its upward movement and also acts as a hold down means for the complete track switch.

It can now be seen that in this form of the invention, the switch rods 12 and 14- lie in a horizontal plane and are slidably mounted between the

needle bearings

74 and 49 located near each end thereof. It can also be seen that the

switch point rails

5 and 6 are fastened to the switch rods by means of the usual switch lugs 56, but in this form of the invention the switch rods support the switch point rails rather than have the switch point rails support the switch rods. Thus, with the bridge members B properly located on the ties 4, the

switch point rails

5 and 6 are suspended a slight distance above the tie plates 3 throughout their length except for a short section near their heel ends where they are attached to the heel blocks.

With the track switch in a normal position as just described, during a switch movement the

switch point rails

5 and 6 are carried on the various switch rods 12 etc. which in turn move over their respective needle bearings 74 so that friction is reduced to a minimum. Also, with the upper sides of the switch rods bearing against their respective needle bearings 49 rather than against the bottoms of the

main stock rails

1 and 2, friction is greatly reduced at this point while still maintaining the desirable feature of providing a positive hold down means for the track switch.

Although the switch rods 12 etc. have sufiicient strength to support the track switch under normal conditions, they are constructed so as to have flexing characteristics under excessive weights. This is desirable so that when a train is present and moving through the track switch the closed switch point 5 may be depressed to again bear on the railroad roadbed tie plates 3, thus relieving the needle bearings 74 of the train weight. This depressing of the closed switch point causes the switch rods to flex throughout its length, thus reducing the load to be carried by the switch rods. This change in position is permitted without damage to the various parts because of the rocker

type bearing surfaces

76 and 77 disposed between the needle or roller bearing structures S4 and the bridge members B.

With particular reference to the needle or roller'bearing structure S3 asproposed for alleviating friction between the switch rods and the underside of the main stock rails, it should be understood that this proposed device could be used on any other type' of track switch assembly wherein the switch point rails are resiliently suspended during a switch movement.

Having shown and described two forms of a needle bearing supporting device for switch points, it should be.

understood that various other adaptations and deviations in the structure and operation could be made without departing from the spirit of the invention within the scope of the appending claims.

What I claim is:

1. in a friction reducing bearing structure for a railroad track switch mounted on ties and having its two switch point rails movable between normal and reverse positions adjacent the stationary stock rails of the track switch, a roller bearing support structure including resilient support means for each movable switch point rail for resiliently supporting its switch point rail above the ties as such rail is moved from one position to the other,

a switch rod interconnecting said two switch point rails and having its ends extending beneath said stationary stock rails, and a roller bearing limit structure mounted beneath each stock rail for receiving its respective end of said switch rod and'rfor permitting longitudinal movement of such switch rod with a minimum of friction between it and the associated stationary stock rail due to' any upward force exerted by said roller bearing structure structure is held heneatth its stock rail by means attached to that stock rail for preventing its longitudinal movement but allowing a limited amount of vertical movement.

4. In a friction reducing bearing structure for a railroad track switch mounted on ties and having its two" switch point rails movable between normal and reverse positions adjacent the stationary stock rails of the track switch, a resilient switch rod interconnecting said two switch point rails and having its ends extending beneath said stationary stock rails, a roller bearing structure mounted beneath each stock rail for receiving its respective end of said switch rod to permit movement of such switch rod with a minimum of friction between it and the underside of its respective stationary stock rail, and a roller bearing structure for each movable switch point rail mounted on each extreme end of said switch rod, and a bridge member located between two ti es adjacent each end of said switch rod for supportng said roller bearing structure in a position to normally cause its switch point rail to be resiliently supported above the ties due to the resiliency of said switch rod.

5. In a railroad track switch mounted on railroad ties and having two switch point rails movable laterally between op-posite positions adjacent the stationary stock rails, a switch rod aflixedly connected to said switch point rails, said switch rod having an upper plane surface extending beneath and spaced from the underside of one of said stock rails, a member interposed between said underside of said one stock rail and said upper plane surface of said switch rod, said member having a lower plane surface opposing said upper plane surface of the switch rod, means connecting said member to said one stock rail against lateral movement, said connecting means allowing limited vertical movement of said member toward and away from the underside of said one stock rail and limited angular movement relative to said stock rail, a plurality of bearing members interposed between and in engagement with said upper and lower plane surfaces and positioned to roll relative to both said upper and lower surfaces as said switch rod moves laterally relative to said member during movement of the switch point rails to opposite positions, and means on one of said opposing surfaces to limit the lateral movement of said bearing members.

6. In a railroad track switch mounted on ties and having switch point rails movable laterally bet-ween opposite positions adjacent the stationary stock rails, a first member connected to and movable with said switch point rails, a second member positioned below said first member, means afi'ixedly connecting said second member to one of said ties against lateral movement but allowing vertical movement relative to said ties, said first and second members having opposing substantially parallel surfaces, a plurality of bearing members interposed between and in engagement with said opposing surfaces to roll laterally relative to both said surfaces simultaneously as said first member moves laterally relative to the second member during movement of the switch point rails to opposite positions, and means interposed between said one tie and said second member and being in engagement with said second member to yieldingly urge constantly said first and second members in one direction normal to the plane or" movement of said switch point rails.

7. In a railroad track switch mounted on railroad ties and having two switch point rails movable laterally between opposite positions adjacent the stationary stock rails, a first member connected to and movable with said switch point rails, said first member having a lower plane surface disposed below one of said switch point rails, a second member interposed between said lower plane surface and one of the railroad ties, said second member having an upper plane surface and being positioned to have said upper surface opposing said lower surface in substantially parallel relationship, means connecting said second member adjacent opposite ends thereof against lateral movement, a plurality of bearing members interposed between and in engagement with said up er and lower surfaces to roll laterally relative to both said surfaces simultaneously as said first member moves laterally relative to said second member during movement of the switch point rails to opposite positions, means on one of said surfaces to limit the lateral movement of said bearing members, said connecting means allowing limited vertical movement of said second member, and spring means interposed between said second member and said one railroad tie and positioned to engage said second member intermediate said connecting means to yieldingly urge constantly said first and second members vertically in one direction.

8. The combination as claimed in claim 7 wherein said connecting means is adjustable to position at opposite ends said seond member a predetermined distance from said ties against the urging of said spring means.

9. In a friction reducing structure for a railroad track switch having its two switch point rails interconnected by switch rods and movable between two opposite positions against the stationary stock rails supported by ties, a bearing structure located beneath each of said switch point rails, a supporting means positioned below and forming part of said bearing structure afiixedly connected against lateral movement supporting each of said bearing structures above the supports of the main stock rails, spring means interposed between the stock rail support and said supporting means positioned to engage at opposite sides thereof both said supporting means and the main stock rail support to yieldingly hold said supporting means spaced from said main stock rail support, and an articulated joint connecting each switch point rail to its respective bearing structure.

References Cited in the file of this patent UNITED STATES PATENTS 1,372,935 Cmeli Mar. 29, 1921 1,599,733 Williams Sept. 14, 1926 1,758,637 Wynn-Williams May 13, 1930 1,965,806 Post et al July 10, 1934 2,185,269 Ryan Jan. 2, 1940 2,245,427 Bone June 10, 1941 2,472,364 Bone June 7, 1949 2,533,929 Gray et al Dec. 12, 1950 2,589,138 Reno Mar. 11, 1952 2,708,285 Greenspon 'et al May 17, 1955 FOREIGN PATENTS 1,546 Great Britain of 1887 209,924 Great Britain Jan. 24, 1924 325,977 Great Britain Mar. 6, 1930

Claims

1. IN A FRICTION REDUCING BEARING STRUCTURE FOR A RAILROAD TRACK SWITCH MOUNTED ON TIES AND HAVING ITS TWO SWITCH POINT RAILS MOVABLE BETWEEN NORMAL AND REVERSE POSITIONS ADJACENT THE STATIONARY STOCK RAILS OF THE TRACK SWITCH, A ROLLER BEARING SUPPORT STRUCTURE INCLUDING RESILIENT SUPPORT MEANS FOR EACH MOVABLE SWITCH POINT RAIL FOR RESILIENTLY SUPPORTING ITS SWITCH POINT RAIL ABOVE THE TIES AS SUCH RAIL IS MOVED FROM ONE POSITION TO THE OTHER, A SWITCH ROD INTERCONNECTING SAID TWO SWITCH POINT RAILS AND HAVING ITS ENDS EXTENDING BENEATH SAID STATIONARY STOCK RAILS, AND A ROLLER BEARING LIMIT STRUCTURE MOUNTED BENEATH EACH STOCK RAIL FOR RECEIVING ITS RESPECTIVE END OF SAID SWITCH ROD AND FOR PERMITTING LONGITUDINAL MOVEMENT OF SUCH SWITCH ROD WITH A MINIMUM OF FRICTION BETWEEN IT AND THE ASSOCIATED STATIONARY STOCK RAIL DUE TO ANY UPWARD FORCE EXERTED BY SAID ROLLER BEARING STRUCTURE IN RESILIENTLY SUPPORTING THE RESPECTIVE SWITCH POINT RAIL ABOVE THE TIES.