Patent GB-190103415-A (GB)
Title: Means or Apparatus for Facilitating the Ascent of Stairs and Inclined Ways.
Inventor: BRENNAN LOUIS
Filed: 1901-02-16
Granted: 1902-05-16
Abstract: 3415. Brennan, L. Feb. 16. Moving handles for facilitating ascent of stairs and inclines.-In connection with stairs, inclines, &c., handles or their equivalent are provided which are caused to travel upwards, when required, and thereby assist people up the stairs &c. Approximately parallel with each flight of stairs, or wit h a corresponding length of the incline &c., is a cylinder 4 in which moves an airtight piston 5 connected to a band 7 which runs round guidepulleys 9, 9a at the ends of the cylinder and has its ends connected to a slide to which the handle 1 (which is shown broken off) is hinged. The air supply to the upper end of the cylinder 4 is controlled by a pair of valves 26, 18, 26 being the exhaust and 18 the admission valve ; a similar pair of valves 26x, 18x, acting in the opposite direction, control the supply of air to the lower end of the cylinder 4. The four valves are of equal area, and the arrangement is such that the pressure admitted by the admission valve tends to open the exhaust valve, and the load closing the exhaust valve tends to open the admission valve. The valves are operated by a yoke 44 engaging the exhaust valve stems. When the yoke is in mid-position, both exhaust valves are open and both admission valves closed, a movement of the yoke to the right admits air to the lower end of the cylinder 4, to cause the descent of the handle, and a movement to the left admits air to the upper end of the cylinder 4 to cause the ascent of the handle. These movements are obtained by varying the tension of the band 7 as described below, the pulley 9 being for this purpose mounted in a sliding frame 34 the movement of which to the right under the pull of the band is resisted by springs 43, 37, and by air pressure on a piston 36 which is always exposed to the pressure in the upper end of the cylinder 4. The compound valve 26, 18, 26<x>, 18<x> thus acts as a reducing-valve which automatically adjusts the downward pressure on the piston 5, so as normally to balance the downward pull on the handle, when the latter is turned up into its horizontal position of use. Waste of compressed air is prevented by an automatic stop valve placed in the passage leading to the valves 18, 18x. This valve is opened by the reduction of pressure on one side of it due to the opening of a relief valve 105 whenever the yoke 44 moves from its mid-position. One end of the band 7 is connected by a yoke 53 to a lever 50, and the other end to the middle of a lever 51, both levers being pivoted to the handle slide. The handle is pivoted by ball bearings 55 to its slide, and, as it is being turned up, a cam 69 raises a bolt 63, which actuates the lever 51 and tightens the band 7. The only result of this, however, is, as described above, exactly to balance the downward pull on the handle, so that no motion takes place. On now pressing on a thumb-push, connected to the rod 58, the lever 51 is actuated further to tighten the band 7, and, since this increase in the band tension is not accompanied by a corresponding pall on the handle, the handle moves upwards at a speed proportional to the pressure on the thumb-push. On the release of the handle, it drops to its vertical position, and the band is slackened enough to allow the valve 18<x> to open and cause the handle to descend. The handle is stopped at the bottom of its run by an incline 62, which engages a lever 61 connected with the lever 50, so tightening the band enough to bring the yoke 44 to mid position. Similar inclines, normally held out of action by springs, are placed at intervals along the guide. When the bolt 63 is raised as described above, a pawl 84 carried by it engages a rack 83, descent of the handle in the event of accident to the band &c. being thus guarded against. The rack comprises teeth arranged alternately on opposite sides of an inverted V-groove, and the pawl is tapered and self-centering. The slot, through which the handle projects from the guide, is protected by a stationary band 99, which is bent upwards, as shown, where it passes through the handle slide. Means are provided for cushioning the piston 5 and handle slide at the ends of their strokes, and for taking the pull of the band 7 off the cam 69 &c. when the handle is turned up. In a modification, the handle is capable of a limited longitudinal play on its slide, and, when pulled downwardly in its turned-up position, causes a grip to close on an endless chain or cable. On then pressing the thumb-push, the lever 51 tightens a band connected with it, and so starts a motor which sets the chain &c. in motion. On releasing the handle, the grip is disengaged by a spring, and means are provided for releasing the grip when the handle nears the end of its travel. The chain &c. may run continuously, in which case the starting-device may be omitted. The Provisional Specification describes a somewhat modified apparatus, in which the upper and lower admission and exhaust valves are at opposite ends of the cylinder 4, and are actuated by a separate band.