GB2282363A - Lifting and lowering device - Google Patents

Abstract

A lifting and lowering device e.g. for beer barrels comprises an upright pillar (2), a load-supporting carriage drivable up and down the pillar (2) under the control of an operator, power means to displace the carnage; at least one haulage rope connected between the power means and the carriage to displace the carriage; a series of spaced apart abutments (4) extending longitudinally of the pillar (2); and a pawl device (11) which is displaceable between an active position (Figure 2) in which an abutment (4) is engaged to prevent carriage movement along the pillar and an inactive position (Figure 3) in which no abutment (4) is engaged to permit carriage movement along the pillar (2), the pawl device (11) being mounted on, and movable with, the carriage, and subjected firstly to the influence of a biassing means (18) to bias the pawl device (11) permanently to its active position and secondly subjected to a greater influence resulting from adequate tension in ropes (3) via adjustable stop (22). <IMAGE>

Description

LIFTING AND LOWERING DEVICE This invention relates to a lifting and lowering device of the general kind known from EP 0382573, which device is adapted to be located in the cellar of a public house etc., and comprises a vertical guide pillar on which is slidably mounted a load-supporting carriage, with the upper end of the pillar terminating at ground/pavement level, and with the carriage displaceable along the pillar by wire ropes connected between the carriage and either an hydraulic ram, having an associated power pack or, an electric motor, under the control of an operator.

The advantages of such a device are widely appreciated, but the creation of slack rope, for whatever reason (typically an obstruction beneath a lowering carriage), can lead to malfunction or even present a hazard to a person, usually the operator, within the cellar.

The object of the present invention is to provide an improved lifting and lowering device over EP 0382573 in which a slack rope condition is automatically countered.

According to the present invention there is provided a lifting and lowering device comprising: (i) a pillar adapted, in use, to be installed in an upright manner; (ii) a load-supporting carriage adapted to be driven up and down the pillar under the control of an operator with the pillar constituting a guide track; (iii) power means to displace the carriage; (iv) at least one haulage rope connected between the power means and the carriage to displace the carriage; (v) a series of spaced apart abutments extending longitudinally of the pillar; and (vi) a pawl device which is displaceable between an active position in which an abutment is engaged to prevent carriage movement along the pillar and an inactive position in which no abutment is engaged to permit carriage movement along the pillar, the pawl device being mounted on, and movable with, the carriage, and subjected firstly to the influence of a biassing means to bias the pawl device permanently to its active position and secondly subjected to a greater influence resulting from rope tension whereby, whilever rope tension exceeds the biassing means, the pawl device is restrained in its inactive position and when the influence of the biassing means exceeds the restraining influence resulting from a slack rope condition occurring and attendant loss of rope tension, the pawl device is displaced automatically to its active position.

Thus, the pawl device, when tripped to its active position as a result of a slack rope condition occurring, positively engages a selected abutment and thereby positively latches the carriage to the pillar at whatever position the carriage finds itself along the pillar when the slack rope condition occurs.

Preferably, a pair of mutually spaced wire ropes are provided, with returning pulleys at the upper end of the pillar. Although the abutments could be constituted by a series of apertures, or of pins or pegs, preferably the abutments are constituted by a series of teeth, preferably profiled into a strip, which conveniently is welded vertically to the pillar, with each tooth preferably providing a horizontal abutment surface engageable by the pawl device.

The means to bias the pawl device to its active position preferably comprises a resilient device such as a coil compression spring, a pack of Belville washers, a leaf or strip spring, or a rubber block, could be provided.

The pawl device is preferably pivotable between active and inactive positions, although it could be linearly displaceable. In the former case the pawl device is preferably constituted by a bell-crank lever, with the lower limb engageable with the nearest tooth and specifically with the underside of the lower limb seatable on the horizontal surface of that tooth, and with the upper limb subjected to the influence of both the biassing means and rope tension.

It follows that with a bell-crank pawl device, the device is pivotally supported for displacement between its active and non-active position.

One embodiment of device will now be described in greater detail by way of example with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a perspective view of the upper end of a pillar of a lifting and lowering device of the general type described in EP 0382573.

Figures 2 and 3 are side elevations of a portion of the pillar of Figure 1, showing the pawl device in its engaged and non-engaged positions respectively with the teeth; and Figure 3 is a perspective view of a portion of the device that is attachable to, and hence displaceable with, the carriage.

In Figure 1 is shown the upper end 1 of a column 2 of rectangular hollow section steel, which column forms part of a lifting and lowering device of the basic type known from EP 0328573. Thus, the column 2 houses a hydraulic ram (not shown), portions of a pair of wire ropes 3 (Figure 4), and return pullies (not shown), whilst a carriage (not shown) suitable for lifting and lowering beer barrels for example, is slidable up and down the column 2 by an operator activating the ram etc. in a known manner.

In accordance with the present invention, a plurality of teeth 4 are burnt from a steel strip 5, which is welded down the outer face 6 of the column over the operational distance of the carriage. Thus, each tooth 4 has a generally horizontal strip surface 7, and a curved lead-in surface 8.

By means of an attachment plate 9 secured to the carriage by bolts or studs passing through holes 10, a pawl device 11 is associated with the teeth 4. From surface 12 of the plate 9 remote from the column 2 extend a pair of spacedapart support lugs 13 carrying a pivot pin 14 for a pawl 15 constructed as a bell crank so having an upper limb 16 and a lower limb 17.

As indicated in Figures 2 and 3, the pawl 15 is pivotable on pivot pin 14 between a tooth engaging position (Figure 2) and a non-engaging position (Figure 3).

The pawl 15 is firstly subject to bias to the toothengaged position by a coil compression spring 18 extending between surface 12 of the attachment plate 9 and inner surface 19 of the upper limb 16.

Secondly, the pawl 15 is subject to greater bias towards the non-engaged position by the pair of wire ropes 3 which are attached to cross-bar 20 which is urged by tension in the ropes 3 in the direction of arrows 21 so that a screw adjustable stop 22 engages outer surface 23 of the upper limb 16 thereby compressing the spring 18 and maintaining the spring compressed, and hence the pawl 15 ineffective, whilever sufficient tension exists in the ropes 3.

However, if during lowering of the carriage the latter fouls an obstruction for example, and a slack rope condition results, the spring 18 instantly and automatically expands, and the lower limb 17 is pushed from the restrained and non-active Figure 3 position into engagement with the next available tooth 4 to engage a tooth surface 7, as indicated in Figure 2, thereby preventing any further lowering of significance of the carriage and locking the carriage to the column, until the problem can be rectified.

Claims (12)

1. A lifting and lowering device comprising: (i) a pillar adapted, in use, to be installed in an upright manner; (ii) a load-supporting carriage adapted to be driven up and down the pillar under the control of an operator with the pillar constituting a guide track; (iii) power means to displace the carriage; (iv) at least one haulage rope connected between the power means and the carriage to displace the carriage; (v) a series of spaced apart abutments extending longitudinally of the pillar; and (vi) a pawl device which is displaceable between an active position in which an abutment is engaged to prevent carriage movement along the pillar and an inactive position in which no abutment is engaged to permit carriage movement along the pillar, the pawl device being mounted on, and movable with, the carriage, and subjected firstly to the influence of a biassing means to bias the pawl device permanently to its active position and secondly subjected to a greater influence resulting from rope tension whereby, whilever rope tension exceeds the biassing means, the pawl device is restrained in its inactive position and when the influence of the biassing means exceeds the restraining influence resulting from a slack rope condition occurring and attendant loss of rope tension, the pawl device is displaced automatically to its active position.

2. A lifting and lowering device as claimed in Claim 1, wherein a pair of mutually spaced wire ropes are provided, with returning pulleys at the upper end of the pillar.

3. A lifting and lowering device as claimed in Claim 1 or Claim 2, wherein the abutments are constituted by a series of teeth.

4. A lifting and lowering device as claimed in Claim 3, wherein the teeth are profiled into a strip.

5. A lifting and lowering device as claimed in Claim 4, wherein the strip is welded vertically to the pillar, with each tooth providing a horizontal abutment surface engageable by the pawl device.

6. A lifting and lowering device as claimed in Claim 1 or Claim 2, wherein the abutments are constituted by a series of apertures, or of pins or pegs.

7. A lifting or lowering device as claimed in any preceding claim, wherein the means to bias the pawl device to its active position comprises a resilient device such as a coil compression spring, a pack of Belville washers, a leaf or strip spring, or a rubber block.

8. A lifting or lowering device as claimed in any preceding claim, wherein the pawl device is pivotable between active and inactive positions.

9. A lifting and lowering device as claimed in any one of Claims 1 to 7, wherein the pawl device is linearly displaceable.

10. A lifting and lowering device as claimed in Claim 8, wherein the pawl device is constituted by a bellcrank lever abutment.

11. A lifting and lowering device as claimed in Claim 10 when appended to Claim 3 and any claim appended thereto, wherein the lower limb of the bell-crank lever is engageable with the nearest tooth and specifically with the underside of the lower limb seatable on the horizontal surface of that tooth, and with the upper limb subjected to the influence of both the biassing means and rope tension.

12. A lifting and lowering device substantially as hereinbefore described with reference to the accompanying drawings.