GB2158032A

GB2158032A - An improved hoist

Info

Publication number: GB2158032A
Application number: GB08509329A
Authority: GB
Inventors: Peter Charles Guilfoyle; David Minshall; Gary Mark Buckley
Original assignee: British Nuclear Fuels PLC
Current assignee: Sellafield Ltd
Priority date: 1984-04-27
Filing date: 1985-04-11
Publication date: 1985-11-06
Also published as: IT8567390A0; IT8553315V0; GB8410886D0; IT8567390A1; IT1183803B; FR2560179A1; JPS60252592A; DE3515224A1; GB8509329D0; BE902296A

Abstract

A hoist for use in restricted headroom including a cylinder (7) having spiral grooves in its outer surface to receive ropes. The grooves cooperate with fixed complementary profiled members (9) to provide a screw connection whereby on rotation the cylinder is axially displaced for winding and unwinding of the ropes. The ropes follow the grooves in the cylinder and coil about the cylinder without overlap. <IMAGE>

Description

SPECIFICATION An improved hoist The present invention concerns a hoist and in particular a hoist capable of operation in a confined space having restricted headroom.

In the nuclear industry, the transport of irradiated nuclear fuel involves loading the fuel into a container and locating the container in a transport flask. The flask can have a removable closure member at one end and can be provided with a hoist at its opposite end such that, with the flask vertical, the container can be lifted into and lowered out of the flask by means of the hoist. As such operations frequently occur in locations having restricted headroom it is desirable to make the hoist as compact as possible and to avoid overlap of the hoist cable or cables during winding and unwinding operations.

According to the present invention a hoist comprises a hollow cylinder axially displaceable along and rotatable with a drive shaft, the cylinder having a spiral groove in its outer surface to receive a cable which groove cooperates with a complementary fixed member to form a screw connection with the cylinder whereby rotation of the cylinder by the shaft causes axial displacement of the cylinder along the shaft to effect winding and unwinding operations with the cable remaining in a same axial position relative to the cylinder.

As a result the cable remains in the same position relative to the cylinder and the axial displacement of the cylinder causes the cable to follow the spiral groove in the cylinder during winding and unwinding.

The invention will be described further, by way of example, with reference to the accompanying drawings; in which: Figure 1 is a schematic part sectional view of a portion of a hoist, Figure 2 is a section on A-A in Figure 1.

A hoist comprises a hollow cylinder 1 mounted on a shaft 2 which is journalled for rotation in bearing assemblies 3 mounted on a support member 4. The support member 4 can be an end closure for a transport flask to receive nuclear fuel.

The shaft 2 is connected through appropriate cou plings to a drive motor likewise mounted on the support member 4. In Figure 1, two steel ropes or cables 5 and 6 are wound about the cylinder 1, the ends of the ropes extending from the cylinder and being guided through openings in the support member 4 to a load within the flask, On rotating the cylinder 1 the load can be lifted and lowered into and out of the flask through a removable closure at the opposite end of the flask.

The cylinder 1 is formed with two spiral grooves 7 and 8 to receive the respective ropes 5 and 6.

The spiral grooves cooperate with guide rollers 9 and 10 respectively journalled on annular support brackets 11 and 12 fixedly mounted on the support member 4. For example, each bracket can support equiangularly spaced apart rollers disposed about the cylinder and engaging the spiral groove.

As seen from Figure 2, the shaft 2 is square section and the cylinder 5 is mounted on the shaft by means of linear bearing assemblies 13. The bearing assemblies 13 are arranged in pairs with each pair supported in a housing 14 fixedly secured to the cylinder 1 and each bearing assembly engaging a respective side of the square shaft 2. The cylinder is thereby coupled for rotation with the shaft and is axially displaceable along the shaft.

In Figure 1, the cylinder is shown at an end position with the ropes wound about the cylinder and located in the spiral grooves. Actuation of the drive motor to rotate the shaft 2 causes the cylinder to rotate and in so doing the cylinder is displaced axially along the shaft of 2 as a result of the bearing assemblies 13 and the screw connections formed between the spiral grooves and the guide rollers 9 and 12. Thus, in Figure 1, as the cylinder moves to the right the ropes 5 and 6 unwind from about the cylinder. Counter rotation of the shaft 2 will effect axial displacement of the cylinder in the opposite direction to wind the ropes about the cylinder 1.

During winding and unwinding, the ropes 5 and 6 follow the grooves in the cylinder and coil about the cylinder without overlap. The position of each steel rope leaving the cylinder remains constant throughout both winding and unwinding operations.

Although in the illustrated embodiment two sets of guide rollers are used to effect axial displacement the same effect can be achieved by using only one set of guide rollers, such as the rollers 9.

1. A hoist comprising a hollow cylinder axially displaceable along and rotatable with a drive shaft, the cylinder having a spiral groove in its outer surface to receive a cable which groove cooperates with a complementary fixed member forming a screw connection with the cylinder whereby rotation of the cylinder by the shaft causes axial displacement of the cylinder along the shaft to effect winding and unwinding operations with the cable remaining in a same axial position relative to the cylinder.

2. A hoist according to Claim 1 in which the screw connection comprises at least one set of guide rollers rotatably mounted on a fixed annular support bracket and engageable with the groove in the cylinder.

3. A hoist according to Claim 2 in which the guide rollers in the or each set are located at equiangularly spaced positions about the cylinder.

4. A hoist constructed, arranged and adapted to operated substantially as herein described with reference to and as illustrated in the accompanying drawings.

5. A hoist according to any preceding Claim when mounted on an end closure of a flask to receive nuclear fuel.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION An improved hoist The present invention concerns a hoist and in particular a hoist capable of operation in a confined space having restricted headroom. In the nuclear industry, the transport of irradiated nuclear fuel involves loading the fuel into a container and locating the container in a transport flask. The flask can have a removable closure member at one end and can be provided with a hoist at its opposite end such that, with the flask vertical, the container can be lifted into and lowered out of the flask by means of the hoist. As such operations frequently occur in locations having restricted headroom it is desirable to make the hoist as compact as possible and to avoid overlap of the hoist cable or cables during winding and unwinding operations. According to the present invention a hoist comprises a hollow cylinder axially displaceable along and rotatable with a drive shaft, the cylinder having a spiral groove in its outer surface to receive a cable which groove cooperates with a complementary fixed member to form a screw connection with the cylinder whereby rotation of the cylinder by the shaft causes axial displacement of the cylinder along the shaft to effect winding and unwinding operations with the cable remaining in a same axial position relative to the cylinder. As a result the cable remains in the same position relative to the cylinder and the axial displacement of the cylinder causes the cable to follow the spiral groove in the cylinder during winding and unwinding. The invention will be described further, by way of example, with reference to the accompanying drawings; in which: Figure 1 is a schematic part sectional view of a portion of a hoist, Figure 2 is a section on A-A in Figure 1. A hoist comprises a hollow cylinder 1 mounted on a shaft 2 which is journalled for rotation in bearing assemblies 3 mounted on a support member 4. The support member 4 can be an end closure for a transport flask to receive nuclear fuel. The shaft 2 is connected through appropriate cou plings to a drive motor likewise mounted on the support member 4. In Figure 1, two steel ropes or cables 5 and 6 are wound about the cylinder 1, the ends of the ropes extending from the cylinder and being guided through openings in the support member 4 to a load within the flask, On rotating the cylinder 1 the load can be lifted and lowered into and out of the flask through a removable closure at the opposite end of the flask. The cylinder 1 is formed with two spiral grooves 7 and 8 to receive the respective ropes 5 and 6. The spiral grooves cooperate with guide rollers 9 and 10 respectively journalled on annular support brackets 11 and 12 fixedly mounted on the support member 4. For example, each bracket can support equiangularly spaced apart rollers disposed about the cylinder and engaging the spiral groove. As seen from Figure 2, the shaft 2 is square section and the cylinder 5 is mounted on the shaft by means of linear bearing assemblies 13. The bearing assemblies 13 are arranged in pairs with each pair supported in a housing 14 fixedly secured to the cylinder 1 and each bearing assembly engaging a respective side of the square shaft 2. The cylinder is thereby coupled for rotation with the shaft and is axially displaceable along the shaft. In Figure 1, the cylinder is shown at an end position with the ropes wound about the cylinder and located in the spiral grooves. Actuation of the drive motor to rotate the shaft 2 causes the cylinder to rotate and in so doing the cylinder is displaced axially along the shaft of 2 as a result of the bearing assemblies 13 and the screw connections formed between the spiral grooves and the guide rollers 9 and 12. Thus, in Figure 1, as the cylinder moves to the right the ropes 5 and 6 unwind from about the cylinder. Counter rotation of the shaft 2 will effect axial displacement of the cylinder in the opposite direction to wind the ropes about the cylinder 1. During winding and unwinding, the ropes 5 and 6 follow the grooves in the cylinder and coil about the cylinder without overlap. The position of each steel rope leaving the cylinder remains constant throughout both winding and unwinding operations. Although in the illustrated embodiment two sets of guide rollers are used to effect axial displacement the same effect can be achieved by using only one set of guide rollers, such as the rollers 9. CLAIMS