Patent Application
20120043431
Not Applicable
Not Applicable
Not Applicable
1. Field of the Invention
The invention pertains to vertically positioning railway switch points by utilizing the motion of two interacting comb structures.
2. Prior Art
For over 150 years switch points have moved by sliding in a horizontal plane. Throughout this long period innovation hopes have been focused on moving the switch points in a vertical plane. The virtues of vertically moving switch points include avoidance of blockage of the movement by snow, ice and debris. However, none of these vertical motion patents have resulted in a practical design that has been implemented. The designs were too weak to withstand the weights and forces experienced during typical railway operation.
In the United States, for example, weights per individual axle exceed 32 metric tons. In addition, tractive effort and braking create longitudinal forces of up to one third of the vertical force.
The advent of high speed rail operations has, strained turnout design even further, with the need to work with small acute angles and high radius switch points. The prior art could neither allow high speeds nor absorb and control such high forces.
There have been many efforts in the prior art to provide switches and similar components having elements moving in a vertical plane rather than in the traditional horizontal plane.
For example, U.S. Pat. No. 1,574,027 for RAILWAY SWITCH, issued Feb. 23, 1926 to Frank M. Freeberg, discloses a switch apparatus having upstanding cross ribs and downwardly projecting lugs under the switch point, such point being moved both horizontally and vertically to rest on the upstanding cross ribs. The patent requires horizontal as well as vertical motion of the point, thereby ensuring that it is not firmly prevented from moving horizontally while under the pressure of traction and braking forces. This makes the design inherently unstable in the longitudinal axis.
U.S. Pat. No. 1,790,548 for RAILROAD SWITCH, ISSUED Jan. 27, 1931 to Albin P. Lofstrand discloses a switch apparatus wherein a lever with a central pivot point and disposed normally to the rails alternately raises and lowers an element at an opposite rail. Rotary motion is employed in the supporting member.
None of the patents and published patent applications, taken singly, or in any combination, are seen to teach or suggest the novel dual comb apparatus of the proposed system.
A switch point is moved in conjunction with two comb shaped structures contained in a largely sealed unit.
The upper comb and attached switch point are moved in a vertical plane. The upper comb has downward facing teeth.
The lower comb moves in a horizontal plane and has upward facing teeth. The lower comb alternatively supports the raised upper comb and switch point or allows the upper comb and switch point to be lowered.
When raised, the switch point engages in wheel contact. When lowered, the switch point avoids wheel contact.
It is, therefore, an object of the embodiment to provide a rugged and dependable switch apparatus that can withstand high forces. It is a further object of the embodiment to provide a switch design capable of extending the upper limits of train speed through diverging turnouts. It is a still further object of the embodiment to provide a switch point in a largely sealed unit that can both exclude debris and facilitate installation.
Base plate 32 rests on the ties. Containment walls 36 and end plates 38 (not shown) encase the system making it a sealed unit except for the top working surfaces. Containment walls 36 are supported by braces 34.
Containment walls 36 act as running rails when their height is set at top of rail elevation. Some containment walls 36 have less elevation so as to allow the flange to pass overhead without contacting switch point 20. Switch point 20 rests on upper comb 22.
Upper comb 22 has teeth that project downward. Lower comb 24 has teeth that project upward. The two combs can be placed one over the other (tooth upon tooth), or alternatively, lower comb 24 can horizontally shift position so that upper comb teeth 23 and lower comb teeth 25 have alternating positions. Upper comb 22 can then descend so that the teeth of the two combs intermesh.
Upper comb 22 and switch point 20 move only in a vertical direction. No horizontal motion is desired or allowed.
Lower comb 24 moves only in a horizontal plane. No vertical motion is allowed. Lower comb 24 movement distance is sufficient to allow upper comb teeth 23 and lower comb teeth 25 to interleave.
The cross sectional contact area of the teeth is greater than the web area of ordinary rail, thereby insuring ample weight distribution without compressive destruction of the teeth.
Located on the sides of upper comb 22 are thrust blocks 26 that fit into thrust block channels 30 on containment walls 36. These insure that upper comb 22 will only move in a vertical plane. Tractive effort and braking effort forces will not be able to shift upper comb 22 out of its fixed longitudinal position.
In
In
For the curvilinear form, lateral teeth alignment follows a radial geometry with the sides of the teeth parallel to a radius line from the curve center.
If longitudinally aligned teeth are used in the curvilinear case, the sides of the teeth follow lines of concentric circles based on the center of such curves. This allows the sets of teeth to properly intermesh. However, such teeth are not geometrically identical when stacked. At the large radius values used in turnouts, however, such a mismatch is insignificant as regards the resulting tooth contact area and the strength of the system.
The tooth array can be arranged so that lower comb 24 moves into machinery space 50 when nested as in
In some embodiments the combs may also be sliced by a vertical plane that follows the sides of switch point 20. The portion of the comb not under the switch point is not bearing train weight and may be trimmed away.
Upper comb 22 has sideways projections termed thrust blocks 26. Matching thrust block channels 30 in containment walls 36 allow the upper comb 22 to move vertically while preventing horizontal motion. Longitudinal forces induced by acceleration or deceleration of the train are transferred from thrust block 26 into channel 30 in containment wall 36. Channel 30 extends downward into machinery space 50.
Extending downward from thrust block 26 is thrust block rod 28 that connects to hydraulic ram 46 that pushes or pulls upper comb 22 and switch point 20 up or down.
Horizontal movement of lower comb 24 is achieved with small hydraulic rams 47. If lower comb teeth 25 are laterally disposed, hydraulic ram 47 is near end plate 38 to push or pull on lower comb 24.
If lower comb teeth 25 are longitudinal or concentric, hydraulic rams 47 are placed at intervals along the length of the system as shown in
The weight of upper comb 22 and switch point 20 may be offset by counterweights 40. Counterweight 40 is periodically connected to rod 28. As rod 28 descends, counterweight 40 moves upward. Counterweight 40 can be linked to rod 28 by levers (not shown) or by flexible cable 41 guided as shown in
Pipe gallery 52 is provided near the bottom of containment walls 36 for power, communication and pneumatic or hydraulic lines.
End plates 38, not shown, enclose the ends of the containment structures. End plates 38 may have openings as needed to allow the passage of lines from pipe gallery 52.
Moving upper comb 22 changes the internal volume of the unit. This forces air in or out through filtered air vents 42 (not shown) installed in end plates 38.
Resting on base plate 32, the system is a largely sealed structure in which water seepage past upper comb 22 is the only invasive material. Small drain holes (not shown) may be provided to release this seepage.
While hydraulic rams 46, 47 have been discussed, additional external ancillary equipment such as pumps, reservoirs, valves, etc., none of which are shown, are not further described or discussed herein as they are entirely within the state of the art for such systems.
To raise switch point 20 into flange contact position, pressure is applied to vertical motion rams 46. These move rod 28 upward and with it upper comb 22 and switch point 20. This movement is followed by pressure on horizontal rams 47 which press on lower comb 24 so as to make lower comb teeth 25 align under upper comb teeth 23. This alignment supports upper comb 22 and switch point 20. As upper comb 22 rises, air is pulled into the interior spaces via filtered air vent 42 located in end plates 38.
To lower a switch point away from flange contact position, pressure is applied to horizontal rams 47. These press on lower comb 24 so as to make lower comb teeth 25 shift position, thereby allowing the nesting of lower comb teeth 25 with upper comb teeth 23. This horizontal movement is followed by downward pressure on vertical rams 46. This moves rod 28, upper comb 22 and switch point 20 downward and causes teeth 23, 25 to intermesh in a nested position. As upper comb 22 moves down, air is expelled from the interior spaces.
The apparatus of the embodiment can handle any switch angle, curvature and speed as needed. The only two major moving parts used are upper comb 22 with switch point 20 and lower comb 24. This makes the novel apparatus into a reliable, rugged, and dependable mechanism that makes the vertical movement concept viable despite the very large forces and speeds found in modern railway practice.
The virtues of such vertically moving switch elements included the traditional objectives of avoiding blockage of the switch point movement by snow, ice and debris. In addition, each switch point mechanism may be pre-assembled and delivered to an installation site as a unified package ready for installation on the crossties.
The cross sectional contact area of the teeth exceeds the normal rail web cross section, thereby ensuring the strength to withstand the large forces of modern rail operations.
Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the embodiment is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of the invention.
