WO2003078294A1

WO2003078294A1 - Hoist

Info

Publication number: WO2003078294A1
Application number: PCT/GB2003/000988
Authority: WO
Inventors: Neal Peter Desorgher
Original assignee: Huntleigh Technology Plc
Priority date: 2002-03-13
Filing date: 2003-03-07
Publication date: 2003-09-25
Also published as: AU2003217006A1; DE60309137T2; EP1483192A1; DE60309137D1; TW200305539A; GB2386593B; GB2386593A; GB0205899D0; GB0305178D0; ATE342864T1; EP1483192B1

Abstract

A retainer has a sleeve (3) urged to a locking position covering a hook opening, by a spring. In use, to attach an accessory, for example, a spreader bar (2) to the hoist (1) lifting arm (1) the hook (4) of the retainer sleeve is slid over a pivot pin (9) of the hoist lifting arm (1) and locking sleeve (3) is urged by spring (7) to a locking position preventing the escape of the pivot pin (9) from the hook (4). To unlock the spreader bar (2) from the hoist lifting arm (1), the retainer sleeve (3) is pushed downwards to disengage the hook (4) from the pivot pin (9). The retainer can be used to enable easy use and dismantling of hoist accessories without removing any components or requiring tools.

Description

Hoist

The present invention relates to hoists, in particular to the attachment of accessories to the suspension point of a lifting arm connected to a hoist column.

It is known to attach accessories to the suspension points of the lifting arm of a mobile hoist by the provision of pivot pins through holes in the suspension point and the accessory, and securing the pivot pins by a removable retainer at one or both ends, for example keyrings or the like. The accessories may also be attached to these suspension points by means of less removable retainers, for example capscrews and/or ' e' rings both requiring tools for their attachment and detachment from the pivot pins .

However, removable retainers such as keyrings are generally awkward to handle and can damage the operator's nails during their removal. Also, the keyrings once removed are frequently misplaced resulting in the hoist being inoperable until replacements are found. Where fixed retainers are used, the accessory cannot be removed once used without the aid of tools, so that changing accessories quickly is not possible. If the retainers and pivot pin are removed to allow the fitting of a different accessory, there is no guarantee that they will be refitted to the manufacturers original specification or that a retainer such as an ^Λe'-ring would not be damaged in a manner that reduces it's performance. The aim of the invention is to provide a safe, quick releasable fastening for attaching a hoist accessory to a hoist. The accessories, for example, a spreader bar, weigh scale or stretcher attachment can be fitted and removed quickly and easily to the lifting arm of a hoist without any tools or without removing any component parts from the accessory or hoist and ensuring that the accessory cannot be detached accidentally from the hoist.

Accordingly, the invention comprises in combination a hoist lifting arm having a pivot pin at one end and a hoist accessory including a retaining means, the retaining means releasably engaging the pivot pin on the lifting arm for pivotal movement of the accessory thereto and having locking means automatically locking the pivot pin in position upon engagement.

Preferably, the locking means is biassed to a locking position, the biassing force being spring means.

By enabling the accessory to be used without the removal of any components or the need for tools it is possible to attach or detach any accessory within seconds without confusion or difficulty.

Preferably, the locking means needs a positive action to be moved to it's unlock position.

An embodiment of the present invention is described below, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of a hoist lifting arm and spreader bar retainer according to the invention; Figure 2 is a schematic diagram of the hoist and spreader bar of Figure 1 with the retainer in locked position; and

Figure 3 is an exploded view of the retainer of Figures 1 and 2. Referring to Figures 1 and 2, a spreader bar 2 is connected to a hoist lifting arm 1 with a retainer according to the invention. The retainer comprises a hook 4 upstanding from the spreader bar 2 to engage with a pivot pin 9 of the hoist lifting arm 1. As shown in Figure 3, the retainer has a sleeve 3 urged to a locking position covering the hook opening by a spring 7. To attach an accessory to the hoist lifting arm 1, in this case the spreader bar 2, the hook 4 is slid over the pivot pin 9 locking sleeve 3 is urged by spring 7 to a locking position preventing the escape of the pivot pin 9 from the hook 4. To unlock the spreader bar 2 from the lifting arm 1, the retainer sleeve 3 is pushed downwards to disengage the hook 4 f om the pivot pin 9. The retainer sleeve 3 is designed in a manner where it will not release if only one side is depressed. This causes the bore through the fabrication to lock onto the spacer 6 as shown in Figure 3. Both sides of the retainer sleeve 3 must be depressed for the mechanism to work reducing the chance of a spreader bar or similar accessory becoming inadvertently detached.

The spreader bar 2 can be used and then removed without the removal of any components or the need for tools, allowing the attachment of any accessory within seconds without confusion or difficulty. Where the hoist is repeatedly moved from one site to another in a car or other small vehicle, the invention reduces moving and handling risks by enabling the dismantling of the hoist lifting arm and accessories easily to reduce the overall weight of parts being lifted when loading/unloading the vehicle .

Figure 3 is an exploded drawing of the retainer according to the invention. The hook 4 has a greased pivot pin 5 located in a hole allowing it to rotate freely. The retainer sleeve 3 is placed over the pivot pin and pushed up to the hook 4. The spacer 6 is slid over the pivot pin 5 and inside the bore of the retainer sleeve 3. The spacer 6 maintains a constant gap between the underside of the hook 4 and the top of the spreader bar 2. The pivot pin 5 is then placed through a hole in the centre of the spreader bar 2 and a collar and spiral pin 8 hold it into position. The force of the spring 7 will ensure that the retainer sleeve 3 always returns to it's locked position.

Instead of the spreader bar 2 any other hoist accessory for example, a weigh scale, or stretcher attachment or similar can be releasably attached with the pivot pin and retainer combination of the invention.

Claims

1. A lifting arm of a hoist having a pivot pin at the lifting end in combination with a hoist accessory including a retaining means, the retaining means releasably engaging the pivot pin for pivotal movement thereto, and locking means automatically locking the pivot pin in position upon engagement.

2. A lifting arm as claimed in claim 1 wherein the locking means is biased to a locking position.

3. A lifting arm as claimed in claims 1 or 2 wherein the locking means requires positive action to return to it's unlocked position.