Improvements in or relating to domestic through-floor, vertical lifts for use by persons with limited mobility

Abstract

 A domestic, through-floor, vertical lift (10) is adapted for use by persons with limited mobility, the lift (10) being of a type serving only two floors and comprising a car (12) adapted and arranged to ascend and descend vertically between the two floors. The car (12) is lightweight and comprises a chassis (16) engaging rails (14) at the back of the car (12) only. Side panels (18) and a floor panel (20) are assembled to each other and to the chassis (16) by interlocking flanges and are held togther by pre-loaded struts (36, 38, 68) in end-to-end compression.
To brake the car (12) from runaway descent, a cord (138) extends up from the car (12) to a low speed governor (144) with a winder (142) which stops unwinding the cord (138) when the descent speed is too fast. The resultant pull on the cord 138 causes it to pull two toothed brake segments (114) into the "on" position, so that their teeth (120) bite into the guide rails (14) to stop the car.
With a mains supply failure to the primary motor 184, a battery-driven secondary motor (192) is arranged to be connected by a clutch (202) to take over from the primary motor (184) and the primary motor brake (210) is released.

Description

Field of the invention

[0001] This invention relates to domestic, through-floor, vertical lifts (in certain countries known as "elevators") adapted for use by persons with limited mobility, the lifts being of a type serving only two floors and comprising a car adapted and arranged to ascend and descend vertically between the two floors.

[0002] British Standard ("B.S.") 5900 and the equivalent International Standard ("I.S.O.") allow for such lifts to be truly vertical or up to 15° away from truly vertical and the term "vertical" herein is to be construed accordingly where the context so admits.

[0003] A person of limited mobility may or may not be wheelchair-bound. For example, a person suffering from emphysema may not be wheelchair-bound but may still require a domestic through-floor lift, more particularly, one with a seat instead of space for a wheelchair.

Summary of Prior Art

[0004] There are known domestic, through-floor, vertical lifts adapted for use by persons with limited mobility, the lifts being of a type serving only two floors and comprising a car adapted and arranged to ascend and descend vertically between the two floors.

[0005] Such lifts have to have a sufficiently small, and sufficiently lightweight, structure, to be accommodated in ordinary domestic homes. Many domestic homes are not strong enough and/or do not have space enough to accommodate either a wheelchair-carrying, stair-climbing lift or a fully-shafted type, passenger-specification, lift.

[0006] The total weight of a loaded lift car comprises the weight of the car itself, plus the total weight of the load being carried, which may be the weight of the person using the lift plus the weight of a wheelchair if carried. From the standpoint of engineering, it is obviously the total weight of the loaded car that matters. If the design of the car itself can be safely altered so as to achieve a reduction in weight, without a significant reduction in the strength of the car, then the weight of the load carried may be correspondingly increased.

[0007] Wheelchairs, especially electric wheelchairs, are often heavy. Moreover, some persons with limited mobility themselves sometimes tend to be heavy, even overweight, as a direct result of their limited mobility and/or their clinical condition.

Summary of the invention

[0008] One object of the invention is to provide a domestic, through-floor, vertical lift, adapted for use by a person with limited mobility, the lift being of a type serving only two floors and comprising a car adapted and arranged to ascend and descend vertically between the two floors, wherein the car itself is of an especially lightweight, and yet robust, design.

[0009] According to a first aspect of the invention, there is provided a domestic, through-floor, vertical lift adapted for use by a person with limited mobility, the lift serving only two floors and comprising a car adapted and arranged to ascend and descend vertically between the two floors, and fixed vertical guide rails located at the rear of the car only and extending between the two floors, the guide rails being engaged by a chassis of the car to guide the car during the ascent and descent of the car, the chassis supporting side panels and a floor panel of the car, the side panels and floor panel extending forwardly of the chassis and forwardly of the guide rails, flanges of the side panels being engaged with flanges of the floor panel for connecting the side panels to the floor panel and vice versa, flanges of the side panels and of the floor panel being engaged with the chassis for connecting the side panels and the floor panel to the chassis, the car comprising struts which extend, at the two sides of the car, between the front and the back of the car and which are preloaded in end-to-end compression and which are arranged so as to place the side panels in tension between the ends of the struts, the preloaded struts serving to hold the side panels and/or the floor panel in place, relative to the chassis, and serving to maintain each side panel and the floor panel interlocked together with each other and with the chassis.

[0010] According to a second aspect of the invention, there is provided a domestic, through-floor, vertical lift adapted for use by a person with limited mobility, the lift serving only two floors and comprising a car adapted and arranged to ascend and descend vertically between the two floors, and fixed vertical guide rails located at the rear of the car only and extending between the two floors, the guide rails being engaged by a chassis of the car to guide the car during the ascent and descent of the car;
   the car comprising speed-sensing means adapted to detect an excessive descent speed of the car, braking means operable by said speed-sensing means, in the event of an excessive descent speed of the car, to positively engage the guide rails for braking the car, said braking means being mounted to a member which is so connected to the chassis, through a kinetic energy-absorption device, that transmission of the braking effect from the member to the chassis results in substantial absorption of kinetic energy by said kinetic energy-absorption device, and hence cushions the chassis against excessive shock being caused to the chassis by the braking.

[0011] Preferably said member is a first, lower, one of two members, one above the other, at the rear of the car, the second member forming a fixed part of the chassis, said kinetic energy-absorption device being in the form of a compressible or crushable member arranged so as to be compressed or crushed between the two members when the braking is effected.

[0012] Such a lift, whilst being relatively inexpensive and simple in construction, avoids excessive physical shock both to the person using the lift and also to the lift itself.

[0013] According to a third aspect of the invention, there is provided an electric motor drive system for a through-floor lift, comprising:-

a mains-powered primary motor having an output shaft drivingly connected to a winch for a car;

a battery-powered secondary d.c. motor drivingly connected through a clutch to said shaft, for lowering the car via the winch in the event of mains power failure to the primary motor;

mains power-failure-sensing means for at least enabling engagement of the clutch, to connect the secondary motor to said shaft, in the event of mains power failure;

and means responsive to mal-operation or non-operation of the secondary motor, in the event of such mains power failure, to disengage the clutch and to cause operation of a brake to brake said shaft, or to brake the winch or the car.

[0014] The above-mentioned means responsive to mal-operation or non-operation of the secondary motor, in the event of such mains power failure, preferably senses the voltage or current of the secondary motor.

[0015] Preferably, the brake is of a type, and is so arranged, that it is applied, for braking the primary motor, when de-energised, and is released, for not braking the primary motor, when energised; and said mains power-failure-sensing means is adapted and arranged to at least enable release of the brake in the event of mains power failure.

[0016] Further features and advantages of the invention will become apparent from the description, which follows, of a preferred embodiment of all three aspects of the invention, reference being made to the drawings.

Description of the drawings

[0017] 

FIG. 1 is a perspective view of part of a through-floor lift forming a preferred embodiment of the invention, showing the car, two guide rails, two lifting cables and a speed-sensor cable;

FIG. 2 is a front elevational view, omitting the door of the car and omitting an inside "skin" of a chassis at the rear of the car;

FIG. 3 is a view on arrow "III" of FIG. 2, omitting an inside skin of one side of the car;

FIG. 4 is an enlarged, fragmentary, elevational view of part of an upper rear corner of the car, showing a side panel interlocked with, and supported upon, the top of a main support member of the car, namely, one of two upright (vertical) beams which form parts of the chassis;

FIG. 5 corresponds to FIG. 4, but omits the side panel;

FIG. 6 is a section on line VI-VI of FIG. 4;

FIG. 7 is a section on line VII-VII of FIG. 2;

FIGS. 8, 9 and 10 are respectively a plan view, a sectional side view and a front end view of a floor panel assembly of the car;

FIG. 11 is a fragmentary sectional view of the connection between the floor panel assembly and either one of two vertical beams of the chassis of the car, at the back or rear of the car;

FIG. 12 is a fragmentary sectional view of the connection between the floor panel assembly and one of the side panels;

FIG. 13 is an exploded perspective view of one of two sloping, prestressed struts at the two respective sides of the car;

FIG. 14 is a fragmentary rear elevational view of parts of the chassis and guide rails, illustrating part of an emergency braking mechanism and a shock absorber mechanism;

FIG. 14A is an enlarged fragmentary view of part of FIG. 14;

FIG. 15 is a section on a (stepped) line XV-XV of FIG. 14;

FIG. 15A is an enlarged fragmentary view of part of FIG. 15;

FIG. 16 is a fragmentary view of the bottom of the car, from inside the door in open position, showing mechanisms for opening and closing the door and for lowering and raising a ramp;

FIG. 17 is an underneath plan view (that is, looking up at the underside from underneath) corresponding to FIG. 16, showing the door of the car in two positions, viz. open in full lines and closed in chain-dot lines;

FIG. 18 is a fragmentary elevational view showing how the hinge, or pivot, of the door is connected to the door;

FIGS. 19 and 20 are respectively a front view and a plan view of lifting and lowering gear, not shown in the other views, at or near the top of the lift; and

FIG. 21 is a block diagram of control circuitry of the lift.

Detailed description of Preferred Embodiment

General Arrangement

[0018] Referring to the drawings and more particularly, to begin with, FIGS. 1-7 of the drawings, the illustrated lift 10 forming the preferred embodiment of the invention comprises a car 12 and a pair of fixed upright guide rails 14a, 14b at the rear of the car 12. It is convenient to mention here that each guide rail 14a, 14b is of a hollow rectangular, preferably square, section, forming a duct for electric cabling (not shown) extending between the top and the bottom of the lift.

Construction of Lift Car 12

[0019] The car 12 comprises:- a chassis 16 at the rear of the car 12; two side panels 18a, 18b mounted to the chassis 16 and extending forwardly of the chassis 16 at the two respective sides of the car 12; and a floor panel assembly 20 mounted to the chassis 16 and to the two side panels 18a, 18b at the base of the car 12.

[0020] The chassis 16 is guided on the pair of fixed upright guide rails 14a, 14b by means of two pairs of shoes 19a, 19b and 19c, 19d which slidingly engage the backs and the insides of the guide rails 14a, 14b, one pair 19a, 19b being at or near the top of the chassis 16, the other pair of shoes 19c, 19d being just above a pair of rollers 21a, 21b, with horizontal transverse shafts, also serving to guide the chassis 16 by running up and down the fronts of the guide rails 14a, 14b near the bottom of the chassis 16.

[0021] The chassis 16 comprises two vertical posts 22a, 22b at the two sides respectively of the car 12 and forming main support members firstly of the chassis 16 itself and secondly of the car 12. The posts 22a, 22b extend the full height of the chassis 16 and thus the full height of the car 12. Each post 22 is of channel section and has a double, inturned, flange 24a, 24b along the outer edge of each side portion 26a, 26b of the post 22. Each flange 24 is a double, inturned, flange in the sense that it comprises two portions 28a, 28b at right angles to one another, that is, forming an L-section, the inner portion 28b being itself at right angles to the adjoining portion 28c of the main body of the post 22, so that the three portions 28a, 28b and 28c of the post 22 form a right-angled U-section.

[0022] A short slot 30 (FIG. 5) is cut into the top of each post 22.

[0023] Each side panel 18 has a double, inturned, flange 32 which extends around the whole perimeter of said side panel 18, imparting rigidity to the side panel 18. A relatively long, vertically-extending portion 32a (FIG. 6) of flange 32 is wrapped around and hence interlocked with the double, inturned flange 24b of the post 22. A short horizontally-extending upper portion 32b (FIG. 4) of flange 32 extends through the slot 30 (FIG. 5) in post 22. A relatively long portion 32c of flange 32 extends at a slope from the front end of flange portion 32b (at the back of side panel 18) down to the top of a relatively short vertical portion 32d of flange 32 at the front of panel 18. Finally, a relatively long horizontal portion 32e of flange 32 extends between the bottom ends of the front and rear vertical flange portions 32d and 32a of flange 32. Each of flange portions 32a-32e, of course, extends along and is substantially coextensive with, corresponding edges of panel 18.

[0024] At the front of the car 12 there are two front vertical posts 34a, 34b, one on either side of the car 12. Two horizontal beams 36a, 36b, one on either side of the car 12, extend rearwardly from the tops of the two front vertical posts 34a, 34b towards the vertical posts 22a, 22b at the rear of the car 12, and are joined thereto via two screw-adjustment devices 38a, 38b respectively. The two screw-adjustment devices 38a, 38b respectively are adjusted so as to push the two horizontal beams 36a, 36b each away from the posts 22a, 22b respectively, thus putting the two horizontal beams 36a, 36b each into end-to-end compression, to act as pre-stressed struts. The combination of each beam 36a, 36b with its respective screw-adjustment device 38a, 38b forms a strut of adjustable length.

[0025] Referring now to FIGS. 8-12, a floor panel assembly 20 of the car 12 comprises a flat panel 42 having two cutouts 44a, 44b at the front thereof to accommodate the two front vertical posts 34a, 34b respectively. A channel-sectioned, transverse, downwardly-facing, flange 46 is welded to the underside of the rear edge of the panel 42, and engages an upwardly-turned double flange 48 welded to the posts 22a, 22b of the chassis 16 as shown in FIG. 11, to support the floor panel assembly 20 from the chassis 12. Referring to FIG. 12, two longitudinally-extending, downwardly facing, flanges 50a, 50b are welded to the undersides of the two longitudinal edges of panel 42, and engage the bottom horizontal portions 32e of flanges 32 of the two respective side panels 18a, 18b. A relatively thick, transversely extending, front edge stiffening rib 52 is welded to the underside of the front edge of the panel 42, whilst a series of rather thinner transversely extending stiffening ribs 54a-54h, spaced apart from each other and from the flange 46 and the rib 50, are also welded to the underside of the front edge of the panel 42 in between the said flange 46 and rib 52.

[0026] Two upstanding brackets 56a, 56b, one on either side, are welded to the front edge of the panel 42, for the floor panel assembly 20 to be jointed to the two front vertical posts 34a, 34b respectively, as shown in FIG. 3.

[0027] Finally, the floor panel assembly comprises two pairs of pulleys 58a-58d on brackets 60a-60d, for guiding two ropes 62a, 62b connecting a so-called "floating skirt" 64, underneath the car 12, to two spring-loaded "lost-motion" devices 66a, 66b of known type, at the sides of the car 12. The function of the floating skirt 64 is the known one of closing an aperture, not shown, in the ceiling, not shown, when the car rises through the aperture in the ceiling to "call" at the floor above, also not shown. (The lift, being designed as a domestic lift for a person of limited mobility, is only designed to serve a ground-level floor and one floor above ground-level.) The floating skirt is of known type and will not be further described.

[0028] The car 12 comprises two further pre-loaded struts, namely, two sloping struts 68a, 68b at the two sides respectively of the car 12, just inside of the respective side panels 18a, 18b. Strut 68a is shown in FIG. 3. Each strut 68 is of adjustable length. The rear, bottom end of each strut 68a, 68b is connected, via a respective bracket 70a, 70b at the rear bottom corner of the car 12 on the respective side, to the respective side panel 18 and to the floor panel assembly 20. The front, top end of each strut 68a, 68b is connected, via a respective bracket 72a, 72b to the flange portion 32c along the sloping front edge of panel 18a, 18b. Referring to FIG. 13, each strut 68 is in two end-to-end connected sections 74a, 74b which engage each other through sloping surfaces 76a, 76b and are adjustably tightened by means of a nut-and-bolt 78 (FIG. 3) to pre-load the strut 68 in end-to-end compression, so that the strut 68 puts the associated panel 18 in tension between the brackets 70 and 72, that is, across the strut 68.

[0029] The combined effect of the pre-loading in end-to-end compression of the struts 36a/38a and 36b/38b and the struts 68a, 68b ensures that the side panels 18a, 18b and the floor panel assembly 20 remain interlocked rigidly together with each other and with the chassis 16.

[0030] It is possible, during assembly of the car 12, to adjust laterally the positions of the two side panels 18a, 18b. Referring to FIG. 7, which shows in plan view the rear end of the horizontal beam 36b and its screw-adjustment device 38b, connecting the rear end of the horizontal beam 36b to the vertical post 22b, a respective one of two gussets 80a, 80b, one at each side of car 12, has a canted side panel 82b which is welded at its front edge 84b as shown to the horizontal beam 36b. A rear flange 86b of gusset 80b is bolted adjustably to post 22b by a lock nut-and-bolt device 88b. [There is a similar assembly, not shown, on the other side of the car, which assembly would carry the suffix "a" for the corresponding parts thereof.] The device 88b comprises:- a bolt 88bl with a bolt head 88b2 engaging the flange 86b as shown in FIG. 7; a locknut 88b3 engaging the opposite side of flange 86b from the bolt head 88b2; and a second locknut 88b4 engaging the post 22b. The post 22b has a backing plate 22b1 attached as shown, to create the necessary thickness of material for the hole therein that the bolt 88b1 extends through to be tapped, that is, screw-threaded, for screw-threaded engagement by the bolt 88b1. It should be clear from FIG. 7, how adjustment of bolt 88b1, followed by tightening of locknuts 88b3 and 88b4, enables adjustment of the spacing between flange 86b and post 22b, so that the side panel 18b can be laterally adjusted inwardly or outwardly as indicated by the arcuate, double-headed arrow in FIG. 7.

Emergency Brake

[0031] Referring to FIGS. 2, 14, 14A, 15 and 15A, especially FIGS. 14, 14A, 15 and 15A, the lift is provided with an emergency brake, which is actuated automatically should the car 12 start to descend too quickly.. More particularly, the chassis 16 comprises a plurality of cross-beams, including in particular two hollow, rectangular-section, cross-beams 100, 102, one above the other, each fixed, in relation to the chassis 16, in that each beam 100, 102 is bolted or welded at its opposite ends to the two vertical posts 22a, 22b at the two opposite sides of the chassis 16. The upper pair of shoes 19a, 19b are bolted to the top cross-beam 100.

[0032] There is a third, channel-section, cross-beam 104, which is not a fixed part of chassis 16, suspended below the two beams 100, 102 as will now be explained. More particularly, a pair of vertical studs 106a, 106b are suspended from the upper fixed cross-beam 100 by virtue of two nuts 108a, 108b at the top of the studs resting upon the cross-beam 100, the studs 106a, 106b extending through respective pairs of vertical through-holes in the three cross-beams 100, 102, 104. Two nuts 110a, 110b on the bottom ends of studs 106a, 106b support the underside of the bottom cross-beam 104, which could slide up the two studs 106a, 106b, but for the provision of a block 112 of a known, kinetic energy absorption material, in the form of compressible or crushable, honeycombed, aluminium, placed in between the two cross-beams 102, 104 and spacing them apart.

[0033] Two toothed sector plates 114a, 114b are pivoted on shafts 116a, 116b respectively to the bottom cross-beam 104. Respective torsion springs 118a, 118b (only spring 118a being shown) on shafts 116a, 116b bias the toothed sector plates 114a, 114b respectively counter-clockwise and clockwise as seen in FIG. 14 - that is, opposite to the direction of the arrows shown on the two toothed sector plates 114a, 114b, to keep their teeth 120a, 120b away from the two guide rails 14a, 14b. Two pulleys 122a, 122b are respectively rotatably mounted, on two shafts 124a, 124b, to a plate or bracket 126. The plate or bracket 126 is not fixed to either the chassis 16 or to the bottom cross-beam 104, but can move relative thereto. A downwardly-depending stem 128 is fixed to the plate or bracket 126 and projects slidably through a block 130 bolted or welded to the bottom cross-beam 104.

[0034] A spring detent 131 (FIG. 14A) within the block 130 normally engages the stem 128 to hold the stem 128, and hence the plate or bracket 126, in the position shown in FIGS. 2, 14 and 15. The spring detent 131 comprises two grub screws 131-1, two helical springs 131-2 and two balls 131-3 housed in two passages in block 130, on either side of stem 128. In a manner well-known, each grub screw 131-1 supports a respective spring 131-2, which urges a respective ball 131-3 against the stem 128 and, normally, into a recess (not visible) in the stem 128. If the pull on the cord 138 is strong enough, the two balls 131-3 pop out of the two recesses in the stem 128, so that the beam 104 is then free to move downwardly relative to the stem 128.

[0035] Two cords 132a, 132b are clamped to the block 130 at 134a, 134b as shown and extend upwardly therefrom as shown in FIG. 14 to pulleys 122a, 122b respectively, around the pulleys 122a, 122b respectively and out to the two toothed sector plates 114a, 114b, to which they are connected at 136a, 136b respectively.

[0036] A cord or rope 138 is connected by a clevis 140 to the plate or bracket 126, and extends upwardly therefrom around idler pulleys 139, 141 (FIGS. 18 and 19) to a winding drum 142 (FIGS. 18 and 19) of a clockwork-spring-powered winder 144, the shaft of which is connected directly to an "overspeed governor" 146.

[0037] In operation, the winder 144 automatically, due to its clockwork spring, winds in the cord or rope 138 as the car 12 ascends. Provided the speed of descent of the lift-car 12 is slower than a certain predetermined maximum value, the winder 144 simply unwinds the cord or rope 138 as the car 12 descends. [How the car 12 is made to ascend and descend is described hereinafter.]

[0038] However, should the car 12 descend too quickly, the governor 146 "locks up", preventing the winder 144 from further unwinding the cord or rope 138, which thereupon exerts a pull upon the plate or bracket 126, disengaging the above-mentioned spring detent from the stem 128.

[0039] Further slight descent (for example a descent of, very approximately, less than fifty millimetres) of the chassis 16, together with all three cross-beams 100, 102 and 104, causes the block 130 on cross-beam 104 to pull on the cords 132a, 132b, which are clamped to block 130 at 134a, 134b, see above. The cords 132a, 132b then pull on their connections 136a, 136b to toothed sector plates 114a, 114b, turning them in the directions of the arrows to bring their teeth bitingly into engagement with the guide rails 14a, 14b respectively, abruptly halting further descent of the cross-beam 104.

[0040] The chassis 12 (including cross-beam 102) continues at first to descend, resulting in the block 112 of honeycombed aluminium being progressively compressed or crushed between the, still descending, cross-beam 102 and the now stationary cross-beam 104, thereby absorbing a considerable amount of kinetic energy and progressively slowing the chassis 16, and hence the car 12, down until the block 112 can be crushed or compressed no further and the car 12 is brought progressively to a halt.

Door and Ramp

[0041] The car 12 comprises a door 150 (omitted in FIG. 2) hinged on a vertical pivot 152 to the front of the left-hand front vertical post 34a (FIGS. 1 and 16 to 18).

[0042] A telescopic electrical actuator 154 is provided as shown, which extends and retracts itself under its own power, to open and close the door 150 respectively. The actuator 154 is pivotally connected at one end of the actuator 154 to a pivot 156 on the door 150, the pivot 156 being spaced a substantial distance from the pivot 152 of the door 150 itself. The actuator 154 is pivotally connected at its other end by a pivot 158 to one end of an angled bracket 160. The other end of the bracket 160 is pivoted by a pivot 162 to the back of the door post 34a. As shown, the pivot 158 is located between the pivots 152 and 156 and is located on an imaginary line interconnecting the pivots 152 and 156. By virtue of the shape of the bracket 160, which is angled as seen in FIG. 17, the pivot 162 is offset from the above-mentioned imaginary line interconnecting the pivots 152 and 156.

[0043] The pivot 158 - by means of which the actuator 154 is pivotally connected to the angled bracket 160 - is constrained by being connected by a slide assembly 157 (FIG. 18) to the underside of the door 150. More particularly, the pivot 158, which is a pin pivot, is secured to a "Nylon" slide 159 which slides linearly within an aluminium guideway 161 which is fixed to the bottom edge of door 150 as shown. The direction in which the pivot 158 is constrained to slide, relative to the door 150, is along the door 150. Without this constraint, the linkage formed by the door 150, the actuator 154 and the bracket 160 would not function properly, but would be very liable to collapse. A cover 163 is provided, over the slide assembly 157.

[0044] Three manually operable switches (not shown) - one within car 12 and the other two at the two floors - are provided for opening and closing the door 150, protected by conventional interlocks preventing opening of the door 150 when the car 12 is not stationary at one floor or the other, and preventing movement of the car 12 when the door 150 is open. Such interlocks are normal and well-known. Extension of the actuator 154 opens the door 150, as shown in FIG. 17 in full lines, whilst retraction of the actuator 154 closes the door 150 as shown in chain-dot lines.

[0045] A ramp 171 is pivoted at 173 to the front edge of the floor panel assembly 20, and is connected by a cord 164 to the door 150 in such a way that the opening of the door from its closed position to a partly open position allows the ramp 171 to pivot down to the floor (not shown) at an inclination of about 1-in-8, to enable a wheelchair-bound person of limited mobility to wheel their chair into the car 12. Conversely, when the door 150 closes, the cord 164 pulls the ramp 171 up again after the door 150 passes the above-mentioned partly open position.

[0046] There is no movement of the ramp 171 during movement of the door 150 between its said partly open position and its fully open position, but the cord 164 merely goes slack.

[0047] If there is a permanent obstruction on one or other floor, preventing the door 150 from opening fully, means not shown can be adjusted to limit the extent to which the door 150 opens. Provided the door 150 is allowed to open far enough, even though not open fully, the ramp 171 is still fully lowered when the door 150 "opens".

Raising and Lowering of the Car 12

[0048] Two strong ropes or hawsers 170a, 170b (FIGS. 1, 2, 14, 15, 19 and 20) are anchored (FIG. 2) at 172a, 172b respectively to opposite ends of an equalising arm 174 which is pivoted at its centre 176 to a rigid member 178 forming part of the chassis 16. The two ropes or hawsers 170a, 170b extend upwardly to two respective, co-axial, directly overhead winding drums 180a, 180b of an overhead electric winch 182 (FIGS. 19 and 20). Besides the two winding drums 180a, 180b, the winch 182 comprises:-

a mains-powered primary A.C. motor 184;

a torque-and-speed converter 186, which may be a gearbox, connected to, and driven by, the output shaft 188 of the primary motor 184 - the two winding drums 180a, 180b being mounted on an elongated transverse output shaft 190 of the torque-and-speed converter 186;

a battery-powered D.C. motor 192 for emergency use in the event of a mains power failure - the battery for secondary motor 192 not being shown in FIGS. 19 and 20;

a drive transmission 194, for transmitting drive from the D.C. motor 192 to the shaft of the A.C. primary motor 184; and

control circuitry (not shown in FIGS. 19, 20).

[0049] The drive transmission 194, for transmitting drive from the D.C. motor 192 to the shaft of the A.C. primary motor 184, comprises a toothed belt 196 running round a smaller toothed pulley 198, on the shaft of the D.C. motor 192, and a larger toothed pulley 200, on the shaft of the A.C. primary motor 184; the drive transmission 194 also comprises an electric clutch 202 for connecting the larger pulley 200 to the output shaft 188 of the primary motor 184.

[0050] The primary motor 184 incorporates a normally applied, electrically releasable, brake 210 (FIG. 21, see below). This brake 210 is released when the primary motor 184 is energised to run and is applied, to brake the primary motor 184, when the primary motor 184 is de-energised to stop, during normal operation of the lift.

[0051] The clutch 202 normally disengages the larger pulley 200 from the primary motor shaft 188 and hence disengages the secondary motor 192 from the shaft 188.

Lift Control and Operating System

[0052] The control and operating system of the lift will be described with reference to FIG. 21, which is a block diagram. Where applicable, the same references are used in FIG. 21 as in FIGS. 1-20.

[0053] Block 212 represents mains electrical supply to the lift. The supply is made, via a mains-power-failure sensing unit 214, to a primary, mains-powered, motor control unit 216, which powers and controls the primary motor 184 as illustrated.

[0054] Within the car 12, as shown diagrammatically in FIG. 3, are primary user controls 218, for use during normal, mains-powered, operation, and connected obviously to the primary motor control unit 216. The mains-power-failure sensing unit 214 is adapted to send a "disable" signal to the control unit 216, to disable the latter, in the event of mains-power-failure.

[0055] Also within the car 12, as shown diagrammatically in FIG. 3, is an emergency user control 220 to enable a person in car 12, if and when desired, to energise the secondary motor 192 to lower the car 12 safely to the lower floor, usually ground level, in the event of mains-power-failure. The mains-power-failure sensing unit 214 is adapted to send an "enable" signal to the control 220, to enable the latter, in the event of mains-power-failure.

[0056] The supply 212 powers a battery-charger 222, for keeping a rechargeable battery pack 224 fully charged except during mains-power-failure. The rechargeable battery pack 224 is arranged to power the emergency user control 220 and the secondary motor 192 to lower the car 12 safely to the lower floor as described above.

[0057] A "brake conditioner" unit 226 transforms and rectifies the mains voltage, to supply a low D.C. voltage to the primary motor brake 210 which, as described above, is a normally applied, electrically releasable, brake.

[0058] The emergency user control 220 is also connected, as illustrated in FIG. 21, to a torque sensor unit 228, which senses the voltage and/or current of the secondary motor 192. The torque sensor unit 228 is "in unit with" a safety shut-down circuit 230, which is operatively connected to the primary motor brake 210.

Normal Operation of the Lift

[0059] During normal operation of the lift, a person of limited mobility can operate external controls, not shown, that is, controls provided at each floor, to call the lift car 12 to that floor and to open the door 150.

[0060] Once inside the car 12, the person, or user, can operate a control (not shown) to close the door 150 and raise the ramp 171, after which an interlock of a standard type responds to door closure to enable the primary controls 218 for the user to direct the car 12 to the other floor, driven by the primary motor 184. Upon arrival, a standard type of interlock, not shown, enables the door control inside car 12 so that the user can operate the door control to open the door 150 and also lower the ramp 171. The usual interlocking arrangement, not shown, prevents operation of the primary controls 218 for the user to direct the car 12 to the other floor while the door 150 is open, of course.

Effect of Mains Failure

[0061] The effect of mains failure is that the sensing unit 214 disables the primary controls 218 and enables the emergency control 220, so that a user who is trapped in the car 12 can operate the control 220 as and when desired. (Means, not illustrated, are also provided for the door 150 to be opened by battery power if the car 12 is located at, or has arrived at, one or other floor. As well as enabling the emergency control 220, the sensing unit 214 must also cause operation of the clutch 202, to couple the secondary motor 192 to the shaft 188 of primary motor 184, for driving the winch to lower the car 12 to the lower floor, and must enable the primary motor brake 210 to be energised and hence released, so that the shaft 188 will turn when the secondary motor 192 is energised by operation of emergency control 220.

[0062] The above is only a general description giving an overview of the control system. Detailed design of a lift control system is a well-understood art, even though complex and requiring considerable skill.

Failure of Secondary Motor to Operate

[0063] In the event of failure of the secondary motor 192 to operate, sensed by the torque sensor unit 228 (which senses the voltage and/or current of the secondary motor 192, the torque sensor unit 228 being "in unit with" the safety shut-down circuit 230, which is operatively connected to the primary motor brake 210, as described above) the primary motor brake 210 is re-applied by being de-energised, to prevent the car 12 from a fast descent out of control.

Operation of Emergency Brake

[0064] If, in spite of all the above precautions, the car 12 starts to descend too quickly, the cord 138 is made to operate the emergency brake as described above.

Claims

1. A domestic, through-floor, vertical lift (10) adapted for use by a person with limited mobility, the lift (10) serving only two floors and comprising a car (12) adapted and arranged to ascend and descend vertically between the two floors, and fixed vertical guide rails (14a, 14b) located at the rear of the car (12) only and extending between the two floors, the guide rails (14a, 14b) being engaged by a chassis (16) of the car (12) to guide the car (12) during the ascent and descent of the car (12), the chassis (16) supporting side panels (18a, 18b) and a floor panel (20) of the car (12), the side panels (18a, 18b) and floor panel (20) extending forwardly of the chassis (16) and forwardly of the guide rails (14a, 14b), flanges (32) of the side panels (18a, 18b) being engaged with flanges (50a, 50b) of the floor panel (20) for connecting the side panels (18a, 18b) to the floor panel (20) and vice versa, flanges (32, 46, 48) of the side panels (18a, 18b) and of the floor panel (20) being engaged with the chassis (16) for connecting the side panels (18a, 18b) and the floor panel (20) to the chassis (16), the car (12) comprising struts (36, 38, 68) which extend, at the two sides of the car (12), between the front and the back of the car (12) and which are preloaded in end-to-end compression and which are arranged so as to place the side panels (18a, 18b) in tension between the ends of the struts (36, 38, 68), the preloaded struts (36, 38, 68) serving to hold the side panels (18a, 18b) and/or the floor panel (20) in place, relative to the chassis (16), and serving to maintain each side panel (18a, 18b) and the floor panel (20) interlocked together with each other and with the chassis (16).

2. A lift (10) as claimed in claim 1, wherein said preloaded struts (68) comprise two preloaded struts (68a, 68b) which slope upwardly and forwardly at the two respective sides of the car (12).

3. A lift (10) as claimed in claim 2, wherein the rear, lower, ends of the two sloping struts (68a, 68b) have connection points (70a, 70b) to the side and floor panels (18a, 18b, 20) at bottom rear corners of the car (12), at or near where the floor panel (20) and the respective side panels (18a, 18b) meet each other and the chassis (16).

4. A lift (10) as claimed in claim 3, wherein the connection points (70a, 70b) of the rear, lower, ends of the two sloping struts (68a, 68b) act to maintain the floor panel (20) in interlocking engagement with the two side panels (18a, 18b).

5. A lift (10) as claimed in any preceding claim, wherein each side panel (18a, 18b) has an upper sloping edge (32c) which slopes downwardly and forwardly, each from a relatively high point at the back end of the sloping edge (32c) to a relatively low point at the front end of the sloping edge (32c).

6. A lift (10) as claimed in claim 5, read as appended to claim 2, 3 or 4, wherein the front, upper, ends of the two sloping struts (68a, 68b) have connection points (72a, 72b) to the side panels (18a, 18b) at said upper sloping edges (32c) of the side panels (18a, 18b).

7. A lift (10) as claimed in any preceding claim, wherein said preloaded struts (36, 38) comprise two preloaded horizontal struts (36a, 36b, 38a, 38b) at the two respective sides thereof, each said horizontal strut (36a, 36b, 38a, 38b) being spaced substantially above the bottom of the car (12), and extending forwardly from the chassis (16) to the front of the associated side panel (18a, 18b).

8. A lift (10) as claimed in claim 7, wherein each said horizontal strut (36a, 36b, 38a, 38b) is adjustably connected to the chassis (16) so that the rear end of the strut (36a, 36b, 38a, 38b) can be selectively turned sideways, inwardly or outwardly, for adjusting the position of the associated side panel (18a, 18b).

9. A lift (10) as claimed in claim 8, wherein each said horizontal strut (36a, 36b, 38a, 38b) is adjustably connected to the chassis (16) by means of a gusset (80a, 80b), the gusset (80a, 80b) projecting inwardly of the strut and being connected to the chassis (16) by means of a laterally inner screw-threaded connection (88b) pulling the gusset (80a, 80b) back towards the chassis (16) and by means of a laterally outer screw-threaded connection pushing the gusset (80a, 80b) forwards away from the chassis (16).

10. A through-floor lift (10) as claimed in any preceding claim, wherein the car (12) comprises speed-sensing means (146) adapted to detect an excessive descent speed of the car (12), braking means (114a, 114b) operable by said speed-sensing means (146), in the event of an excessive descent speed of the car (12), to positively engage the guide rails (14a, 14b) for braking the car (12), said braking means (114a, 114b) being mounted to a member (104) which is so connected to the chassis (16), through a kinetic energy-absorption device (112), that transmission of the braking effect from the member (104) to the chassis (16) results in substantial absorption of kinetic energy by said kinetic energy-absorption device (112), and hence cushions the chassis (16) against excessive shock being caused to the chassis (16) by the braking.

11. A domestic, through-floor, vertical lift (10) adapted for use by a person with limited mobility, the lift (10) serving only two floors and comprising a car (12) adapted and arranged to ascend and descend vertically between the two floors, and fixed vertical guide rails (14a, 14b) located at the rear of the car (12) only and extending between the two floors, the guide rails (14a, 14b) being engaged by a chassis (16) of the car (12) to guide the car (12) during the ascent and descent of the car (12);
   the car (12) comprising speed-sensing means (146) adapted to detect an excessive descent speed of the car (12), braking means (114a, 114b) operable by said speed-sensing means (146), in the event of an excessive descent speed of the car (12), to positively engage the guide rails (14a, 14b) for braking the car (12), said braking means (114a, 114b) being mounted to a member (104) which is so connected to the chassis (16), through a kinetic energy-absorption device (112), that transmission of the braking effect from the member (104) to the chassis (16) results in substantial absorption of kinetic energy by said kinetic energy-absorption device (112), and hence cushions the chassis (16) against excessive shock being caused to the chassis (16) by the braking.

12. A lift (10) as claimed in claim 10 or 11, wherein said member (104) is a first, lower, one of two members (102, 104), one above the other, at the rear of the car (12), the second member (102) forming a fixed part of the chassis (16), said kinetic energy-absorption device (112) being in the form of a compressible or crushable member (112) arranged so as to be compressed or crushed between the two members (102, 104) when the braking is effected.

13. A lift (10) as claimed in claim 12, wherein said compressible or crushable, kinetic energy absorber, device (112) is a honeycomb-like structure of metal, such as aluminium.

14. A lift (10) as claimed in any one of claims 10 to 13, wherein said speed-sensing means (146) comprises a speed-governor (146) connected to a self-winding mechanism (144) that normally winds up and unwinds a braking means-operating cable (138) as the car (12) ascends and descends or vice versa, the arrangement being such that excessive descent speed of the car (12) causes the speed-governor (146) to lock the self-winding mechanism (144), thereby causing the braking means-operating cable (138) to operate the braking means (114a, 114b).

15. A lift (10) as claimed in claim 14, wherein the braking means-operating cable (138) is adapted to disengage spring detent means (131) in order to operate said braking means (114a, 114b).

16. A lift (10) as claimed in any preceding claim, wherein the car (12) comprises a door (150) at the front thereof.

17. A lift (10) as claimed in claim 16, wherein the door (150) is a swing door.

18. A lift (10) as claimed in claim 17, wherein said swing door (150) is connected by means (164) to a retractable or pivoted ramp (171) in such a manner that the ramp (171) is opened out as the door (150) opens and is closed up as the door (150) shuts.

19. A lift (10) as claimed in claim 18, wherein the connection of the door (150) to the ramp (171) is so adapted that the ramp (171) is fully opened out before the door (150) is fully open.

20. A lift (10) as claimed in claim 17, 18 or 19, wherein adjustable means is provided for limiting the extent to which the door (150) can be opened, in order to avoid an obstruction.

21. A lift (10) as claimed in any preceding claim, wherein the guide rails (14a, 14b) are of box-section and wherein at least one of the rails (14a, 14b) forms a duct for electric cabling of the lift (10).

22. An electric motor drive system for a through-floor lift (10), comprising:-

a mains-powered primary motor (184) having an output shaft (188) drivingly connected to a winch (182) for a car (12);

a battery-powered secondary d.c. motor (192) drivingly connected through a clutch (202) to said shaft (188), for lowering the car (12) via the winch (182) in the event of mains power failure to the primary motor (184);

mains power-failure-sensing means (214) for at least enabling engagement of the clutch (202), to connect the secondary motor (192) to said shaft (188), in the event of mains power failure;

and means (228) responsive to mal-operation or non-operation of the secondary motor (192), in the event of such mains power failure, to disengage the clutch (202) and to cause operation of a brake (210) to brake said shaft (188), or to brake the winch (182) or the car (12).

23. A motor drive system as claimed in claim 22, wherein the brake (210) is of a type, and is so arranged, that it is applied, for braking the primary motor (184), when de-energised, and is released, for not braking the primary motor (184), when energised; and wherein said mains power-failure-sensing means (214) is adapted and arranged to at least enable release of the brake (210) in the event of mains power failure.

Drawing