A METHOD FOR SWITCHING RAILWAY SWITCHES AND A RAILWAY SWITCH FOR CARRYING OUT THE METHOD

Abstract: In a railway switch there are used actuator means (8, 12, 14; 9, 13, 15) co-acting with drive means (16; 17) to move the points (4; 5) alternatively in a vertical direction between an active position in which the tread surface (4b; 5b) of respective points lie on the same level as the tread (2b; 3b) on the head of an adjacent rail, and a lowered inactive position out of the path of a flange (6a; 7a) of a flanged wheel (6; 7) running on the tread of the stock rail (2; 3). The means for actuating the points (4; 5) includes arms (8; 9) which, while using the intrinsic resilience of the points, can be swung about horizontal axes (10; 11) located on the sleepers (1) centrally thereon. The points (4; 5) and the stock rails (2, 3) have provided thereon mutually co-acting and mutually engaging guide surfaces (2e; 4e; 3e; 5e) which guide the points in their pivotal movement between their active and inactive positions. A spacer block (18; 19) inserted between respective stock rails (2; 3) and points (4; 5), the width of which spacer block increases from the tip of the point to the root thereof. The spacer block has provided thereon a guide surface (18e; 19e) for co-action with a corresponding surface (4e; 5e) on the point (4; 5). Protection is also sought for a method of switching the points in a railway switch of this kind.

Description: A method for switching railway switches and a railway switch for carrying out the method Field of Invention The present invention relates to a method for switching railway switches comprising sleeper-carried stock rails and points which are preferably actuated by separate actuators and are alternatively movable in a substan- tialla vertical direction between an active or operative position in which the tread surface, or upper surface, of respective point, or tongue, is located on the same level as the tread surface, or upper surface, of an adjacent rail head, and a lowered, inactive or inopera¬ tive position in which the point is out of reach of the flange of a railway wheel on the tread surface of the stock rail. The invention also relates to a switch, and more speci¬ fically to a switch of the kind described in the pre- amble of claim 7. Background Prior Art Various kinds of switches are known to the art in which the tongues or points of the switch move vertically when the switch is switched from one crossing to another. An example of one such construction is described and illustrated in SE-A-642,698 (Tailland) . This construc¬ tion, however, is in its entirety much too exposed to the elements for use in winter, and requires such pene- trative exploration into the sleepers as to jeopardize the load-bearing capacity of the switch. Another serious drawback with this known switch construction is that the wheel flanges are intended to be guided in tracks embodied in the rails, which is most unsuitable in the case of high—speed switches. Aϋ-B-62861/80 (Daimler-Benz) describes a similar switch which incorporates a track-like groove and therewith has the same drawbacks. US-A-1 ,790,548 (Lofstrand) describes a switch construc- tion in which the points, upon pivotal movement, are either brought into plane-vertical abutment with the stock rails, which experience has shown to be imprac¬ ticable, especially in the case of high-speed switches in view of the ensuing risk of derailment, or into inclined abutment and more robust point tips. This has the drawback that when the points, or tongues, occupy their lowered position they are out of abutment with the stock rails, thereby enabling dirt, ice and snow to enter between the points and stock rails to prevent satisfactory switching of the points. US-A-792,646 (Byron) describes a similar construction in which there is also the risk that dirt will penetrate in a manner to render switching of the points difficult, and with which there is a serious danger of parts of the switch freezing together in winter. A further examp ' le of such switches encumbered with corresponding drawbacks and shortcomings is described in US-A-1 ,112,965 (Andersson) , DE-B-1 ,158,538 (Krug & Co) and NO-B-127,715 (Elektro-Thermi ) . Object of the Invention One object of the present invention is to provide a method for switching railway points, and a railway switch, which substantially eliminates problems result¬ ing from the ingress of sand, dirt, snow and ice, and also the risk that movable parts of the switch will freeze together during winter months. Another object is to provide a method and a switch of the aforesaid kind which eliminate substantially the need to remove snow from the point or tongue arrange¬ ments. Still a further object is to provide a switch which a) can be manufactured at low costs, b) requires the minimum modification to present day railway switch constructions, and c)' the novel and modified parts of which are constructed for simple manufacture, afford long and reliable service in use, and can be assembled for quick and simple care and maintenance. Summary of the Invention These and other objects are achieved with a method according to the present invention, which is mainly characterized in that the switch points are carried by actuators in the form of arms which are caused to swing about horizontal axes located between the points while utilizing the elasticity of the points; and in that this swinging or pivotal movement is guided by mutually engaging surfaces and mutually co-acting guide surfaces having a concave and a convex arcuate shape, respectively, and located between respective stock rails and points. The points and stock rails of the inventive switch are arranged to engage one another in such close relation¬ ship as to prevent the compaction of snow and ice there¬ between when switching from one crossing to another, in the absence of electric heating devices. This enables the various drawbacks encountered hitherto with known switching methods to be avoided. In practice, the arms are preferably caused to pivot about axes which are located centrally on respective sleepers between the points, or tongues, and which are preferably mutually coincidental. In this case, the mutually engaging guide surfaces, which fit against one another, are of an arcuate configuration with the centre of the arc lying between the points, from the tips thereof to the location on the point construction at which the distance between the point and the stock rail permits a wheel flange to pass freely. As a point is swung, the extent to which the point moves will decrease progressively from this location down to the root of the point from about 50 mm to 0. As a result of this forced guidance of the points, from the point tip to said location, the points will execute a uniform rotational movement about their respective longitudinal axes when moved from their active to their inactive positions. This movement will thus decrease progressively down to zero, from the aforesaid location to the root or base of the point." The tips of respective points are made as wide as possible, in order to ensure that they have sufficient mechanical strength and resistance to wear. To this end, the pivot journals of respective arms are placed at low locations on the sleepers concerned. According to one preferred embodiment of the invention, the pivotal movement of respective points between an inactive and an active position is steered by a spacer block arranged between the stock rail and the point, the width of which block increases from the tip of the point to its root. Further, there may be support shoes on a number of sleeper blocks from the spot of free passage of wheel-flanges up to the tongue or point root against the central rail. The level of the tread on the point in the lowered position of the point is preferably constant from the tip up to the spot for free passage of wheel flanges, but is then successively raised up to the root of the point, the point being held laterally by the widest end of the spacer block out of the path of a wheel flange on the stock rail before the tread surface of the point falls to the level of the lowest part of the flanged wheel. In practice it is also preferred that support devices, supported by the sleepers and preferably carried on rollers or ball-runners, are moved in under the points when said points are swung up to their respective active positions. In this regard, the same actuator means, connected to a drive means, may simultaneously move a plurality of support shoes forming part of a shoe-unit out of an active position and a corresponding number of opposing support shoes in respective shoe-units into an active position. According to another aspect, the invention also relates to a railway switch, the main characteristic features of which are disclosed in the following apparatus claims. An embodiment of the invention will now be described in more detail with reference to the accompanying schematic drawings. Brief Description of the Drawings Figure 1 is a plan view of a part of a switch constructed in accordance with the invention; Figure 2 is a side view-of the switch taken on the line II-II in Figure 1 ; Figures 3-8 are vertical sections through the switch taken on the lines III-III, IV-IV, etc. up to and including VIII-VIII in Figure 1 ; Figure 9 is an enlarged view of part of the switch illustrated in Figure 1 , with the point being shown in its rest position in full lines and in its active position in chain lines. Description of a Preferred Embodiment The illustrated switch includes sleepers or cross-ties 1 which carry respectively in a known manner stock rails 2 and 3 and points, or tongues, 4 and 5. The stock rails 2 comprise a rail head 2a which presents a tread surface 2b, a web 2c, and a rail foot 2d. The right-hand rail consists of corresponding parts 3a-3d. Auxiliary actuating devices in the form of arms 8 and 9 which, in the. illustrated embodiment, can be swung about axes 10; 11 coincidental with respective sleepers 10, are provided for vertical movement of respective points between an active position in which the tread surface 4b, 5b of respective points lie in the same horizontal plane as the tread surface of an adjacent rail head 2b, 3b, and a lowered rest position in which the tread surface of the point is out of reach of a flange 6a of a flanged wheel 6 running on the tread or track surface of the stock rail. The arms 8 are connected to a drive device 16, in the form of an hydraulic piston-cylinder device, via linkages 12, 14 " . The arms 9 are also connected to a corresponding hydraulic piston-cylinder device 17, via linkages 15, 13. The point or tongue 4 is carried by the arm 8 at a location thereon spaced from the place at which the arm is connected to the linkage 12, whereas the point or tongue 5 is carried by the arm 9 at the outer end thereof. The coincident axes 10; 11 of the arms 8, 9 are compa¬ ratively low on the associated sleepers 1. Movement of the points 4, 5 between their inactive position and their active position is effected with the aid of the elasticity of the points. Bending and turning operations take place at the spot of free passage of the wheel flanges, cf. Fig. 5. The tongue is then forced to be rotated, elevated and lowered non-uniformly between the fixed point root (Fig. 8) and said spot; uniformly, however, up to the tip 4a of the point or tongue (Fig. 3) . As will be seen from Figure 9, movement-of the left- hand point 4 is steered by mutually engaging guide surfaces, namely one guide surface 2e on the rail 2 and one guide surface 4e on the point 4. The rail 3 and the point 5 present corresponding guide surf-ces 3e and 5e, respectively. The guide surfaces 2e and 4e engage one another in such close mutual contact as to prevent particles of dirt, e.g. sand, or snow from penetrating therebetween and therewith impair the function of the switch. In the sectional views of Figures 3, 4 and 9, the guide surface 2e is located on a thickened part of the web 2c of rail 2. In the sectional view of Figure 5, the thickened rail portion has the form of a separate spacer block 18 which incorporates a guide surface 18e for co-action with the guide surface 4e on the point 4. As will be seen from the Figures 3-4, the point 4 has a convex arcuate guide surface 4e which co-acts with a concave arcuate guide surface 2e or 18e on the stock rail 2 and the spacer block 18, respectively. These guide surfaces have mutually the same radius. Figures 6 and 7 show that the tread or track surface of the point 4 in its downwardly lowered position present a rising level and from rotation successively re-assumed horizontal position from Fig. 5 to the root of the point seen in Fig. 8. At the said rail distance or length the point has an arcuate guide surface 2e, 4e (Fig. 6) between the point and a support shoe 29, 31. At the location - illustrated in Figure 5 - at which the thickness of the spacer block 18 corresponds to, or is slightly larger than the width of the wheel flange 6a, the .level of the tread surface 4b on the tip of the point 4 is still beneath the wheel flange 6a and out of contact therewith. Mounted on the sleepers 1 are mounting pads 20, 21, for the stock rails 2, 3, while separate support plates 22, 23 carrying shoes 24, 25 are mounted on the support pads 20, 21, said support plates 22, 23 being provided with rollers or ball-runners. The support shoes 24, 25 are joined to form a shoe-unit which is manipulated by drive means 30 in the form of hydraulic piston-cylinder devices, through an auxiliary device 28. When activa¬ ting the drive and auxiliary devices, the shoe-units are moved in one and the same plane between an active position, in which they lie beneath a point in the active position of said point and an inactive position in which they lie on one side of the point in the inactive position of said point. In this respect, one shoe 24 is moved to an active position at the same time as an opposing shoe 25 is moved to an inactive position, and vice versa. The switch also incorporates sealing and protecting plates arranged between the points 4, 5. These plates include parts 32, 33 which are located between the rails 2, 3 and which can swing together with the points 4, 5, and stationary protective parts 34 which lie outwardly of the point drive means. The plate parts 32, 33 cover the whole area between respective points from the tip to the root of each point. The construction of the switch will now be described with reference to a simple left-hand switch with a cross-over angle of approximately 1:9, i.e. the track curve in the switch deviates to the left from the straight track, commencing from the tips of the points. The right-hand 'Stock rail 3 is straight with its point or tongue 5 curved to the left, whereas the left-hand stock rail 2 is curved to the left and has a straight point or tongue. When a railway vehicle approaches the curve in the switch, a light signal placed on the upline side of the switch signals that the vehicle is "in the curve". This means that the light signal has received a clearance signal, or proceed signal, from two point control contacts 26, 27, which in turn signifies that the left-hand point 4 is in its inactive or rest position and that the right-hand point 5 is in its active position; that the hydraulic piston-cylinder devices 30 have inserted the support shoes 25 beneath the right-hand point 5; and that the shoes 24 for the left-hand point 4 have been inserted beneath the pro¬ tective hoods 32a on the covering plate surface.32 and therewith ensure that the right-hand wheel-flanges 7a of the vehicle follow the right-hand point 5, whereas the left-hand wheel-flange does not reach the left-hand point 4. When the vehicle is to move along the straight track, it is necessary to switch over the points. This is done in the following manner: a) The light signal is set to "stop" while the points are being switched; b) The hydraulic piston-cylinder devices 16 are activated to lift the left-hand point 4 to its active position; c) The hydraulic piston-cylinder devices 30 insert the support shoes 25 for the right-hand point 5 in beneath the protective hoods 33a, and the support shoes 24 for the left-hand point 4 in beneath said point; d) The hydraulic piston-cylinder devices 17 for the right-hand point lower the point to its inactive position; and e) The point control contacts deliver a proceed signal to the light signal, therewith changing the stop signal to a proceed signal for movement onto the straight section of track in the switch. If the weather conditions are such as to render it possible for the points 4, 5 to freeze solidly to a corresponding stock rail 2 or 3, a safety device in corresponding hydraulic piston-cylinder devices 16, 17 is brought into function when the points are to be raised or lowered. Upon activation of this safety device, two vibrators (not shown) are automatically activated, therewith to crush any ice-film which might be present, causing it to lose its grip. This obviates the need to heat the points or stock rails electrically. The illustrated and described embodiment of a switch construction according to the invention can be modified and changed in various ways within the inventive scope of the following claims. Examples of such modifications include an increase in the number of sleepers 1 , and an increase or decrease of the distance between the point root and the location on the point arrangement at which the distance between the point and the adjacent stock rail affords passage of wheel-flanges. Furthermore, the hydraulic piston-cylinder devices 16, 17 operative in moving the points can be replaced with electric motors, and the hydraulic piston-cylinder devices 30 operative in moving the support shoes can be replaced with electric linear motors. When vibrators are used, they can be placed at rail and point locations where they will produce the best effect. The need for upwardly projecting protective hoods 32a, 33a on the plate surface covering the space between the points can be avoided by suspending the shoe-units 24a, 25a beneath respective plate surfaces and providing recesses on the upper side of the sleepers for accommo¬ dating the shoes 24, 25 when respective points are in their inactive positions. Thus, the invention enables points to be switched fully automatically even when high train speeds in the track curve require-crossing angles which reach to between 1:12 and 1:15. Furthermore, the invention enables the points to be switched totally manually, by means of four "switch levers". The invention affords considerable advantages even in this regard, inter alia, since the need to remove snow, oil-laden gravel and dust, leaves and similar rubbish likely to occur on, e.g., industrial railway tracks, can be avoided. The invention also affords the possibility of constructing semi-automatic switches or turn-outs, in which case only one switch operating lever is required. When maintenance work is to be carried out on the switch, or turn-out, such as insertion of the sleepers 1 beneath the rails, the plate surface extending between the points or tongues 4, 5 and comprising readily handled metal sheets 32, 33, is removed. The protective hoods 32a, 33a, can also be made detachable if considered suitable. From the above description follows that the switch con¬ struction according to this invention incorporates switch points or tongues which are also rotatable about their longitudinal axes. The points constantly lie against a respective stock rail and move upwardly and downwardly in a vertical plane. Consequently, it is possible to retain points and stock rail constructions that were developed more than a century ago. The points are each guided for movement by at least two mutually parallel and movable arms which are attached to the points and extend at right angles thereto from the track. When switching the points, the respective points and arms together describe a circular sector against the stock rails with a length of arc of for instance about 55 mm and a radius of arc equivalent to the length of the arms, which- with a view to said arcuate surfaces are given mutually the same lengths. The points are guided and driven essentially at the location at which the distance of the points from the stock rails allows the passage of wheel flanges, the raising, lowering and lengthwise rotation of the points decreasing progressively from said location through a distance of for instance about 4f5 meters along support shoes arranged on each sleeper and adapted for tight or close abutment with the points, up to the root of the point where the stationary intermediate rail of the crossing starts.

Claims: Claims 1. A method for operating a railway switch comprising sleeper-carried stock rails and switch points or tongues, said points preferably being activated by separate actuating means and being alternatively movable in a substantially vertical direction between an active position, in which the tread or upper surface of respective point is located on the same level as the tread or upper surface of an adjacent rail head, and a lowered inactive position in which it is beyond the reach of the flange of a railway wheel on the tread of the stock rail, c h a r a c t e r i z e d by swinging actuating devices in the form of arms carrying the points about horizontal axes arranged between the points while utilizing the inherent resilience of the points, and by steering said swinging movement with the aid of mutually co-acting and mutually engaging guide surfaces having a concave and a convex arcuate shape, respective¬ ly, and located between the stock rails and the points. 2. A method according to claim 1, c h a r a c t e¬ r i z e d by causing the arms to swing about the axes which are located centrally between the points on sleepers ' and which are preferably coincidental. 3. A method according to claim 1 or 2, c h a r a c¬ t e r i z e d by steering said swinging movement of the points between the inactive and active position with a spacer block which is inserted between the stock rail and the point and the width of which increases from the top of the point to the root thereof. 4. A method according to claim 3, c h a r a c t e¬ r i z e d by raising the level of the tread on the point, in the lowered position thereof, from the tip of the point to the root thereof; and by holding the point laterally out of the path of a flanged wheel on the stock rail with the aid of a spacer block, prior to the point reaching the level of the lowermost part of the wheel flange. 5. A method according to any of claims 1-4, c h a r a c t e r i z e d by inserting support units carried on the sleepers under the point in its raised active position, said support units preferably being provided with rollers or ball-runners. 6. A method according to claim 5, c h a r a c e- r i z e d by moving simultaneously a plurality of support shoes associated with the support units out of an active position and a corresponding number of opposing support shoes into an active position by means of one and the same actuating means connected to a drive means. 7. A railway switch, comprising sleeper-carried stock rails (2; 3) and points (4; 5); and further comprising actuator means (8, 12, 14; 9, 13, 15) which co-act with drive means (16; 17) for moving the points (4; 5) alternatively in a substantially vertical direction between an active position in which the tread surface (4b; 5b) of respective points (4; 5) lie on the same level as the tread (2b; 3b) on the hea (2a; 3a) of an adjacent support rail, and a lowered inactive position out of the path of a flange (6a; 7a) of a flanged wheel (6; 7) running on the tread of the stock rail (2; 3), c h a r a c t e r i z e d in that the means for actuating the points (4; 5) includes arms (8; 9) which, while using the intrinsic resilience of the points, can be swung about horizontal axis (10; 11) located on the sleepers (1) preferably centrally thereon; and in that the points (4; 5) and the stock rails (2, 3) have provided thereon mutually co-acting and mutually engaging guide surfaces (2e; 4e; 3e; 5e) having a convex, arcuate shape on the tongues and a concave arcuate shape on the support rails, respective¬ ly, said guide surfaces guiding the points in their pivotal movement between said active and said inactive position. 8. A switch according to claim 7, c h a r a c t e¬ r i z e d by a spacer block (18; 19) inserted between respective stock rails (2; 3) and points (4; 5), the width- . of which spacer block increases from the tip of the point to the root thereof; and in that the spacer block has provided thereon a guide surface (18e; 19e) for co-action.with a corresponding surface (4e; 5e) on the point (4; 5). 9. A switch according to either claim 7 or claim 8, c h a r a c t e r i z e d in that the point (4, 5) presents a convex arcuate surface (4e; 5e) for co-action with a concave arcuate guide surface (4e; 5e; 18e; 19e) provided on the stock rails (2; 3) and on the spacer blocks (18; 19), respectively, said arcuate guide surfaces having mutually the same radius of arc. 10. A switch according to claim 9, in which in the lowered position of the point (4; 5) the tread of said point has a level which rises from the tip (4a; 5a) of the point to the root thereof, c h a r a c t e r i z e d in that at the location at which the width of the spacer block (18;- 19) corresponds to the width of the flange (6a; 7a) of the wheel (6; 7) the tread (4b; 5b) of the point still lies beneath and out of contact with the flange of said wheel. 11. A switch according to any of claims 7-10, c h a r a c t e r i z e d in that a drive means (30) is arranged to move, in one and the same plane, support shoe units, which are supported by the sleepers (1) and preferably provided with rollers or ball-runners, between an active position between a respective point (4; 5) in the active position of said point, and an inactive position on one side of the point when the point occupies its inactive position, a shoe (24; 25) belonging to the shoe units being moved to its active position simultaneously as an opposing shoe (25; 24) is moved to its inactive position. 12. A switch according to any of claims 7-11, c h a r a c t e r i z e d in that there are arranged between the points (4; 5) sealing and protecting means (32; 33) in the form of plates that comprise parts which are located between the rails (2; 3) and capable of being pivoted together with the points (4; 5), and preferably stationary parts (34) which lie protectively outside the point drive-means.

Inventors: LOENNBERG TAGE, LOENNBERG, TAGE
Applicants: LOENNBERG TAGE, LOENNBERG, TAGE
Application year: 1987
Main classification: E01B7
IPC codes: E01B7