Railway switches and signals – Fluid-motor actuation
Patent
1998-05-21
2000-03-07
Le, Mark T.
Railway switches and signals
Fluid-motor actuation
B61L 500
Patent
active
060329068
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to point drive units for driving railway points (switches) to move.
Referring to FIG. 1, certain railway points 1 (illustrated only partially) are conventionally driven by a pneumatic cylinder 2 installed generally centrally between two of the rails 3 of the railway track. The cylinder is controlled remotely via pipes 4. An alternative arrangement, which is illustrated in FIG. 2, is to drive the points using a hydraulically self-contained unit, which requires no remote hydraulic supply. The unit shown schematically in FIG. 2 has an electrically driven hydraulic pump 5 which pressurises fluid from a local reservoir 6 to drive a hydraulic cylinder 7. The unit is too large to fit between the rails so the cylinder is coupled to the points via a linkage shown schematically at 8.
To save space and the use of vulnerable supply pipes, it is desirable to have the drive unit installed entirely in the space between the rails of the track. However, the space between the rails is limited, particularly in multi-rail railways, so any unit that is to fit between the rails must be very compact. Also, as shown in FIGS. 1 and 2, the points typically have a connecting rod 9 which lies generally parallel with and generally centrally between two of the rails. The natural approach in designing units to fit between the rails has therefore been to try to mount a cylinder in line with the connecting rod 9 as has previously been the case in systems like that shown in FIG. 1. However, it has now been appreciated that locating the cylinder in this way has prevented the other components of a unit more complex than that shown in FIG. 1 being arranged so that the unit can fit between the rails.
FR-A-2 649 060 discloses a point drive unit in which a cylinder is mounted laterally offset to one side of a central longitudinal axis of a housing including control means. An electro-hydraulic control is mounted at a location laterally adjacent the cylinder but the cylinder is still in line with the connecting rod of the points.
According to the present invention there is provided a point drive unit for driving railway points to move via a connecting means of the points comprising a connecting rod located generally centrally between and lying parallel with two of the rails of the railway track, the unit comprising: housing having a central longitudinal axis which is generally centrally located between said two of the rails and generally parallel with them in use of the unit; said longitudinal axis of the housing for driving the points, the cylinder being mounted within the housing at a location laterally offset to one side of said longitudinal axis of the housing; the cylinder for controlling the supply of fluid to the cylinder to control the movement of the piston; and the piston is laterally offset from the connecting rod.
With the cylinder laterally offset to one side of the housing the drive unit can be made more compact than before.
Preferably the control means comprises one or more of: the reservoir; either end of the cylinder; Items of the control means may be provided in a manifold.
The housing is preferably adapted to be installed between the rails by being of a such a size that it can be installed between the rails without interfering with other equipment and/or by being provided with fixing means located to allow it to be fixed securely in place between the rails. As stated above, the housing is adapted to be installed so that its central longitudinal axis (that is the axis half way between its outermost lateral walls) is generally centrally between said two of the rails and generally parallel with them, the central longitudinal axis of the cylinder then being offset laterally from the central longitudinal axis of the housing. Said two of the rails are preferably adjacent rails to each other.
Preferably the offset coupling comprises an arm for linking the connecting means to the piston so that the proximal end of the connecting means (that is the end nearest the drive unit) and the distal end of the piston
REFERENCES:
patent: 1015138 (1912-01-01), Cordero
patent: 1251218 (1917-12-01), Gonzales
patent: 1775811 (1930-09-01), Coleman
patent: 3842256 (1974-10-01), Crutsch et al.
patent: 4428552 (1984-01-01), Frank et al.
patent: 4870906 (1989-10-01), Schaffer et al.
patent: 5687935 (1997-11-01), Durchschlag et al.
Burton Colin
Jones Lee Antony
Potter William George
Le Mark T.
Westinghouse Brake and Signal Holdings Limited
LandOfFree
Point drive unit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Point drive unit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Point drive unit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-355313