GB2183212A

GB2183212A - Apparatus for handling loads

Info

Publication number: GB2183212A
Application number: GB08528893A
Authority: GB
Inventors: G H Williams
Original assignee: HANDLING CONSULTANTS Ltd
Current assignee: HANDLING CONSULTANTS Ltd
Priority date: 1985-11-23
Filing date: 1985-11-23
Publication date: 1987-06-03
Also published as: GB2183212B; GB8528893D0

Abstract

Lifting apparatus employing ropes has an axially movable winding drum to maintain a fixed rope path. As the rope is wound onto the winding drum the drum is axially moved to wind the rope in a progressive and orderly manner. The winding drum assembly is mounted on a sub frame which is driven relative to a fixed main frame. By this means the rope path may be substantially fixed. The means driving the sub frame may be driven directly by the winding drum. <IMAGE>

Description

SPECIFICATION Improvements to equipment for handling loads This invention relates to equipment used for handling loads, particularly, although not exclusively, unit loads that are handled by overhead cranes.

Usually the ropes from which the load is suspended are attached to, or pass over, rope anchors, pulleys or sheaves and winding drums. In the case of anchors and pulleys, or sheaves, the path of the rope, or ropes, remain substantially fixed, at least in one plane, during the action of lifting. However, this is not the case with winding drums, where, as the rope is wound in it must progress along the drum to form an orderly layer, or layers. If the rope passes directly from the drum to the load handling system the path of the rope will be displaced as the drum winds off, or winds on, the rope.

If the load is hanging freely then all, or a proportion, of this displacement will be communicated to the load. In a typical crane application this will result in a lift path for the load that is not truly vertical. In certain cases a truly vertical lift must be maintained.

In other application the rope passes from a winding drum over a fixed sheave or pulley. In order to prevent undue rope wear the angle between the plane of the rope (between the pulley and drum), and the plane of the pulley must not exceed certain values. In particular applications there may not be sufficient space to enable the pulley to be set at the desired distance from the drum in order to limit the said angle in relation to the required size and proportion of the winding drum.

In addition, there are limitations regarding the angle between the plane of the rope adjacent to the drum, and the plane at right angles to the axis of the winding drum.

This invention particularly relates to applications where a constant, or near constant, rope path is required, in relation to adjacent items, during winding onto, or winding off from, a drum.

According to the present invention, there is provided a powered winding drum assembly, a sub frame to support winding drum assembly a main frame with means to slidably attach the sub frame, means to cause displacement between the sub frame and the main frame.

In a preferred arrangement the means to cause displacement, between the sub frame and the main frame is coupled directly to the powered winding drum.

By the above arrangement the powered winding drum is caused to move in a direction substantially parallel to the axis of the winding drum and at a rate and direction so as to counter the progression of the rope along the winding drum.

One specific embodiment will be described, by way of example only, with reference to the accompanying drawings.

Figure 1 shows a side view of the equipment.

Figure 2 shows a sectional view cut on plane A-A.

Figure 3 shows a plan vew at the beginning of a lifting operation.

Figure 4 shows a plan view at the end of the lifting operation.

As shown in Fig. 1 the equipment comprises a powered winding drum assembly 1 which is mounted onto a sub frame 2. The sub frame is slidably attached to a main frame 3 by sliding means 4. The main frame 3 may be fixed to a supporting structure (not shown) or form part of an overhead crane (not shown). In the latter case main frame 3 would form part of the cross travel carriage.

The main frame 3 supports a pulley 5, mounted on a shaft 6 fixed to the main frame.

A rope 7 is wound onto the drum 1, passed over the pulley 5, and then down to the load attaching means 8.

A shaft extension 9 forms part of the winding drum assembly and rotates with the winding drum. Attached to the shaft extension 9 is a sprocketed wheel 10 which engages a chain 11. This chain engages a further sprocketed wheel 12 which is attached to a shaft 13.

Shaft 13 is rotatably mounted, but restricted from endwise movement by a bearing assembly 14. The bearing assembly is fixed to an extension 15 of the sub frame 2.

Over part of the length of shaft 13 is formed a screw thread 16 which cooperates with a nut 1 7 fixed to an extension 18 of the main frame 3.

In operation, as the drum 1 is revolved, the sub frame is moved relatively to the main frame 3 and the associated pulley 5, so at to maintain the rope at the same angle relative to both the drum 1 and the pulley 5. This operation is illustrated in Figs. 3 and 4.

1. Equipment for handling loads comprising a powered winding drum assembly, a sub frame to support the powered winding drum assembly, a main frame with means to slidably attach the sub frame, means to cause displacement between the sub frame and the main frame.

2. Equipment for handling loads as claimed in claim 1 wherein the means to cause displacement between the sub frame and the main frame is driven by the rotation of the winding drum.

3. Equipment for handling loads as claimed in claim 1 wherein the means to cause displacement between the sub frame and the main frame is provided by equipment separate from the winding drum equipment.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements to equipment for handling loads This invention relates to equipment used for handling loads, particularly, although not exclusively, unit loads that are handled by overhead cranes. Usually the ropes from which the load is suspended are attached to, or pass over, rope anchors, pulleys or sheaves and winding drums. In the case of anchors and pulleys, or sheaves, the path of the rope, or ropes, remain substantially fixed, at least in one plane, during the action of lifting. However, this is not the case with winding drums, where, as the rope is wound in it must progress along the drum to form an orderly layer, or layers. If the rope passes directly from the drum to the load handling system the path of the rope will be displaced as the drum winds off, or winds on, the rope. If the load is hanging freely then all, or a proportion, of this displacement will be communicated to the load. In a typical crane application this will result in a lift path for the load that is not truly vertical. In certain cases a truly vertical lift must be maintained. In other application the rope passes from a winding drum over a fixed sheave or pulley. In order to prevent undue rope wear the angle between the plane of the rope (between the pulley and drum), and the plane of the pulley must not exceed certain values. In particular applications there may not be sufficient space to enable the pulley to be set at the desired distance from the drum in order to limit the said angle in relation to the required size and proportion of the winding drum. In addition, there are limitations regarding the angle between the plane of the rope adjacent to the drum, and the plane at right angles to the axis of the winding drum. This invention particularly relates to applications where a constant, or near constant, rope path is required, in relation to adjacent items, during winding onto, or winding off from, a drum. According to the present invention, there is provided a powered winding drum assembly, a sub frame to support winding drum assembly a main frame with means to slidably attach the sub frame, means to cause displacement between the sub frame and the main frame. In a preferred arrangement the means to cause displacement, between the sub frame and the main frame is coupled directly to the powered winding drum. By the above arrangement the powered winding drum is caused to move in a direction substantially parallel to the axis of the winding drum and at a rate and direction so as to counter the progression of the rope along the winding drum. One specific embodiment will be described, by way of example only, with reference to the accompanying drawings. Figure 1 shows a side view of the equipment. Figure 2 shows a sectional view cut on plane A-A. Figure 3 shows a plan vew at the beginning of a lifting operation. Figure 4 shows a plan view at the end of the lifting operation. As shown in Fig. 1 the equipment comprises a powered winding drum assembly 1 which is mounted onto a sub frame 2. The sub frame is slidably attached to a main frame 3 by sliding means 4. The main frame 3 may be fixed to a supporting structure (not shown) or form part of an overhead crane (not shown). In the latter case main frame 3 would form part of the cross travel carriage. The main frame 3 supports a pulley 5, mounted on a shaft 6 fixed to the main frame. A rope 7 is wound onto the drum 1, passed over the pulley 5, and then down to the load attaching means 8. A shaft extension 9 forms part of the winding drum assembly and rotates with the winding drum. Attached to the shaft extension 9 is a sprocketed wheel 10 which engages a chain 11. This chain engages a further sprocketed wheel 12 which is attached to a shaft 13. Shaft 13 is rotatably mounted, but restricted from endwise movement by a bearing assembly 14. The bearing assembly is fixed to an extension 15 of the sub frame 2. Over part of the length of shaft 13 is formed a screw thread 16 which cooperates with a nut 1 7 fixed to an extension 18 of the main frame 3. In operation, as the drum 1 is revolved, the sub frame is moved relatively to the main frame 3 and the associated pulley 5, so at to maintain the rope at the same angle relative to both the drum 1 and the pulley 5. This operation is illustrated in Figs. 3 and 4. CLAIMS

4. Equipment for handling loads substantially as described herein with reference to Figs. 1 to 4.