GB2146599A - Girder trolley - Google Patents

Abstract

A girder trolley includes a carrier member 4 and a suspension member 24 that are movable axially relative to each other, a pair of support members 10, 11 pivotable on the carrier member, and means e.g. links 21, 22, pivotally connecting the support members to the suspension member, whereby movement of the suspension member relative to the carrier member in a direction away from the support members causes movement of the support members towards each other. The support members may be furnished with rigidly attached arms 8, 9 and with rollers 14, 15 that engage with the web and lower flanges of an I-section beam 2. The trolley may serve as an anchor for a safety line attached to a person working on a steel structure. Alternatively, one of the support members is fixed relative to carrier member. <IMAGE>

Description

SPECIFICATION Girder trolleys This invention relates to girder trolleys.

The problem exists during the erection and inspection of structural steel work that those who have to work on the structure need to be provided with a safety line against the risk of falling.

The use of a safety line is frequently inhibited by the difficulty of moving the line as the person to whom it is attached moves. The present invention provides an arrangement by means of which a line attached to a person working on a steel structure may be attached easily and securely to the structure and be moved easily as the person moves.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 illustrates a perspective view of a girder trolley attached to a girder and Figure 2 shows an end view of the arrangement shown in Figure 1 with a part of the arrangement shown in chain-dotted lines in the open position.

Referring to the drawings, there is shown the lower part 2 of an i girder. Clamped on the part 2 of the girder is a trolley 3 which includes a tubular carrier member 4 having at its upper end a bracket 5.

The bracket 5 provides pivot points 6 and 7 for respective arms 8 and 9. To the end of each of the arms 8 and 9 there is rigidly connected a support member 10 and 11 respectively, by means of respective brackets 12 and 13. At the other ends of each of the support members 10 and 11 there are arranged a pair of roller bearings 14 at right angles to the longitudinal axes of the members 10 and 11.

Beneath the support members 10 and 11 there is arranged a respective roller bearing 15 having its axis parallel to that of the longitudinal axis of the respective support member.

The arms 8 and 9 each carry a respective bracket 17 and 18. The bracket 17 provides a pivot point 19 and the bracket 18 provides a pivot point 20.

Respective levers 21 and 22 are pivotally connected at the points 19 and 20 to the brackets 17 and 18 and at their other ends the levers 21 and 22 are pivotally connected at 23 to a tubular suspension member 24 which carries an attachment ring 25. The tubular suspension member 24 is movable longitudinally in the tubular carrier member 4 and may be fixed relative thereto by a pin 26 passed through holes in the members 4 and 24. The pin 26 is secured in position by a split pin 27.

Reference is now made particularly to the arrangement in the chain-dotted position shown in Figure 2.

In order to reach this position, the pin 26 is removed and the tubular suspension member 24 is moved so that the attachment ring 25 approaches the tubular carrier member 4 and the pivot point 23 is raised until the levers 21 and 22 are substantially horizontal. In this position the arms 8 and 9 are pivoted outwardly about the pivot points 6 and 7 so that the roller bearings 14 and 15 clear the edges of the lower part 2 of the girder. This action enables the trolley 3 to be removed from or positioned upon the lower part 2 of the girder.

In making use of the trolley 3, the pin 26 shown in the drawings is removed and the tubular suspension member 24 is moved upwards into the tubular carrier member 4, with the resilt that the pivot point 23 is moved towards the bearings 14 and 15 and the arms 8 and 9 are pivoted away from one another.

This movement results in the movement of the bearings 14 and 15 to the chain-dotted positions shown in Figure 2 and enables the support members 10 and 11 to be moved past and positioned above the horizontally extending foot of the girder part 2.

The support members 10 and 11 are maintained at this level relative to the girder and the suspension member 24 is then moved downwards relative to the tubular carrier member 4, resulting in the movement of the arms 8 and 9 into the solid-line position shown in Figures 1 and 2 and in the support members 10 and 11 closing towards one another, so that the bearings 14 and 15 abut the vertical and horizontal surfaces of the girder part 2 respectively. The trolley 3 thus becomes hooked on to the girder and the trolley assembly is locked in this position by the insertion of the locking pin 26 through both the tubular carrier member 4 and the tubular suspension member 24.A safety line (not shown) is connected between the attachment ring 25 and a person who is to be safeguarded against the risk of falling and it will be understood that, as the person moves, the trolley 3 is able to move easily along the girder part 2 on the bearings 14 and 15 so that the person is secured easily while given considerable freedom of movement.

It will be understood that although the invention has been described, by way of example, with reference to a particular embodiment, it is possible to make variations and modifications which fall within the scope of the invention.

Thus, although in the particular embodiment a pair of hinged arms 8 and 9 and support members 10 and 11 have been shown, it would be possible to connect one of the arms and its respective support member rigidly to the main carrier member 4 and to have only the other of the arms pivotally connected to the main carrier member 4. Other means of locking the assembly than the use of the pin 26 may be employed. It is also possible to provide stops on the suspension member 24 arranged in such a way that the relative movement between the members 4 and 24 is limited. It will be noted that, in the embodiment described, a force exerted downwardly from the ring 25 always causes the assembly to move the support members towards one another and to secure the trolley upon the girder more firmly, even should the pin 26 shear. The relative positions of the pivot points 7,20 and 23 are such that a downwardly exerted force on the ring 25 always results in a clamping action on the girder. It will be noted that, even when the suspension member 24 is moved upwardly within the tubular carrier member 4, the position in which the levers 21 and 22 are horizontal provides the maximum opening between the support members 10 and 11 and that, in this position, the bearings 14 and 15 only just clear the girder part 2. Further movement of the member 24 upwards would result in the members 10 and 11 being brought together. The particular embodiment employs square section tubular members, but other shapes and sections may be used, and the trolley may be made in any suitable material giving the necessary strength including alloys.

Claims (7)

1. A girder trolley including a carrier member, a suspension member, the carrier member and the suspension member being movable relative to one another, a pair of support members, the support members being connected to the carrier member, and one of the support members being pivotable about the carrier member, and means pivotally connecting the said one of the support members to the suspension member, whereby movement of the suspension member relative to the carrier member in a direction away from the support members causes relative movement between the support members towards one another.

2. A girder trolley as claimed in claim 1 in which the other of the support members is pivotable about the carrier member and means is provided to connect pivotally the other of the support members to the suspension member.

3. A girder trolley as claimed in claim 2 in which the means connecting each of the support members to the suspension member is a respective arm, each arm being pivoted with respectto its support member such that when the arms are in line the opening between the support members is at a maximum.

4. A girder trolley as claimed in any one of the preceding claims in which the carrier members is tubular and the suspension member is movable within the carrier member.

5. A girder trolley is claimed in any one of the preceding claims including means to lock the carrier member and the suspension member against relative movement.

6. A girder trolley as claimed in any one of the preceding claims having roller bearings on the support members arranged to run on a girder.

7. A girder trolley as claimed in claim 1 substantially as described herein with reference to the accompanying drawings.