Hoist mechanism

Abstract

 A hoist includes a support structure (14) adapted to be positioned over a load (L). A carriage (30) is mounted on the support structure (14) for reciprocal movement between retracted and advanced positions respectively overlying the load (L) in its lowered and raised positions. A rotatable guide (38a, 38b, 38c) is mounted on the carriage (30). A flexible elongated tension element (40a, 40b, 40c) is attached at one end to the support structure (14) and passes over the rotatable guide (38a, 38b, 38c) to depend downwardly therefrom. The other end of the tension element (40a, 40b, 40c) is detachably connected to the load (LI, and as the carriage (30) is reciprocated between its retracted and advanced positions, the load (L) is raised and lowered along a path inclined with respect to the horizontal.

Description

[0001] This invention relates generally to hoist mechanisms and is concerned in particular with a hoist for raising and lowering loads along paths which are inclined with respect to the horizontal.

[0002] There are many industrial applications requiring loads to be raised and lowered along inclined paths. This is particularly true of rod and tube rolling mills where rolling stands, work rolls, drives and motors often are inclined at angles of 45° with respect to the horizontal. Conventionally, such components are raised and lowered along inclined rails, tracks or the like. However, such rails or tracks are cumbersome, and they reduce access to the components being serviced and handled.

[0003] The present invention avoids the drawbacks of the prior art by eliminating any need for inclined rails, tracks or the like when raising and lowering loads along inclined paths.

[0004] In a preferred embodiment of the invention, this is accomplished by the use of a hoist mechanism in which a flexible tension line is fixed at one end and passes over a pulley for connection to a load positioned beneath the pulley, the pulley being movable along a fixed generally horizontal path toward and away from the fi::ed end of the line such that the length of line between the pulley and the load is progressively lengthened and shortened respectively and the load is thereby conveyed in respective directions along a path inclined to the horizontal.

[0005] Preferably, the path along which the load is raised and lowered is generally at 45° to the horizontal.

[0006] Advantageously, three tension lines are provided, each with its own pulley and with the centre of gravity of the load being located within a triangle defined by the downwardly extending portions of the tension lines.

[0007] A more detailed description of one particular example of the invention will now be provided with reference to the accompanying drawings, wherein:

Figure 1 is a plan view of a hoist embodying the present invention;

Figure 2 is a sectional view taken along line 2-2 of Figure 1;

Figure 3 is an enlarged sectional view taken along line 3-3 of Figure 1; and

Figure 4 is a plan view in section taken along line 4-4 of Figure 2.

[0008] Referring to the drawings, a hoist mechanism is shown overlying a load "L" to be handled, in this case a roll cartridge inserted at a 45° angle with respect to the horizontal into a roll housing 10 of a rolling mill 12. This type of mill is employed, for example, in the single strand rolling of rods and other like products.

[0009] The apparatus includes a support structure 14 having side channels 16 rigidly interconnected by end braces 18a, 18b and by an intermediate brace 18c. The support structure has legs 20 with wheels 22 arranged to run along rails 24, thereby permitting the support structure to be movably positioned over the load L. The lower flanges of the side channels 16 have guide tracks 26 arranged thereon. The tracks 26 define a horizontal path of travel indicated diagramatically by the line 28 in Figure 2.

[0010] A carriage has front and rear axles 32, 34 with wheels 36 on their ends arranged to run along the guide tracks 26. The rear axle carries a pair of freely rotatable guides, in this case sheaves 38a, 38b, and the front axle likewise carries a single sheave 38c. Flexible elongate tension elements, for example wire ropes 40a, 40b, and 40c are connected at one end to the intermediate brace 18c of the support structure. The ropes 40a, 40b and 40c extend respectively over the sheaves 38a, 38b and 38c and depend downwardly thereform. The lower ends of the ropes have hooks 42 connected thereto by means of adjustable turnbuckle assemblies 44.

[0011] The hooks 42 engage a lifting attachment 46 having a depending leg 48 arranged to be detachably connected by any convenient means, such as for example bolts, pins or the like, to the load L. The arrangement of the sheaves 38a, 3b and 38c is such that, as can best be seen in Figure 4, the depending portions of the ropes 40a, 40b , 40c are located at the corners of a reference triangle within which is located the centre of gravity 50 of the load L.

[0012] An operating means which conveniently may comprise a piston cylinder unit 52 is attached at one end to the end brace 18a of the support structure and at the opposite end to the carriage 30. The unit 52 operates to reciprocate the carriage between a retracted position (shown in solid lines in Figres 1 and 2) overlying the load L in its lowered position, and an advanced position (shown by broken lines in Figures 1 and 2) overlying the load in its elevated position.

[0013] The apparatus operates in the following manner: when lifting a load L, the support structure 14 is first moved along the rails 24 to a position overlying the load. The carriage 30 is retracted, causing the depending portions of the ropes 40a, 40b and 40c to lengthen, and thereby placing the hooks 42 in the vicinity of the load. The lifting attachment 46 is then connected to the load, and the hooks in turn are connected to the lifting attachment. Thereafter, the piston cylinder unit 52 is extended, causing the carriage to move from left to right as viewed in Figure 2. As this carriage movement takes pl-ace, the depending portions of the ropes 40a, 40b and 40c are generally shortened as the ropes ride over their respective sheaves 38a, 38b, 38c. The net result is that load L is lifted along a path "P" extending at an angle of 45° to the horizontal. Once the load is clear of its housing 10, the support structure can be shifted along rails 24 to another location at which the load is deposited. The load may be lowered back into its housing along the same path P retracting the piston cylinder unit 52.

[0014] During the course of raising and lowering the load, the turnbuckle assemblies 44 may be adjusted to correct any slight angular misalignment, particularly as the load is being inserted into its housing.

[0015] The number of ropes can of course be varied to suit particular requirements, and in some cases one may suffice. Any suitable flexible element, including cables or chains, may be employed instead of wire ropes. Also, other means such as for example a horizontal screw actuator driven by an electric motor in concert with a brake may be employed to reciprocate the carriage on the support structure. In any case, however, the load may be raised and lowered without resort to cumbersome inclined tracks, thereby allowing the area around the housings 10 to remain fully accessible to maintenance personnel.

Claims

1. A hoist for raising and lowering a load along a path which is inclined with respect to the horizontal, and characterised by a support structure (14) adapted to be positioned over the load (L); a carriage (32, 34, 36) mounted on the support structure (14) for reciprocal movement therealong between retracted and advanced positions respectively overlying the load (L) in its lowered and raised positions; a rotatable guide (38a, 38b, 38c) mounted on the carriage; a flexible elongate tension element (40a, 40b, 40c) attached at one end to the support structure (14) and passing over the rotatable guide (38a, 38b, 38c) to depend downwardly therefrom, means (42, 44) for detachably connecting the other end of the tension element to the load; and operating means (52) for reciprocating the carriage between the retracted and advanced positions.

2. The apparatus of claim 1 wherein the carriage is reciprocated horizontally on the support structure.

3. The apparatus of claim 2 wherein the path along which the load is raised and lowered is arranged at a 45⁰ angle with respect to the horizontal.

4. The apparatus according to either of claims 1, 2 or 3 wherein the support structure is movably mounted on guide rails (24).

5. The apparatus of claim 1 wherein there are three of the tension elements (40a, 40b, 40c) extending over and depending downwardly from three of the rotatable guides (38a, 38b, 38c), the depending portions of the tension elements when viewed in plan being arranged at the three corners of a triangle.

6. The apparatus of claim 5 wherein the means for detachably connecting the other ends of the tension elements to the load is adapted to locate the centre of gravity of the load within the triangle.

7. The apparatus of claim 1 wherein the operating means comprises a double acting piston cylinder unit (24) having opposite ends connected respectively to the carriage and the support structure.

8. A hoist mechanism for raising a load along a path which is inclined to the horizontal, and characterised by a flexible tension line (40a, 40b, 40c) fixed at one end, the line passing around a freely rotatable guide (38a, 38b, 38c) and being detachably connected at its other end to a load (L) positioned beneath the guide, and by means (24) for advancing the guide along a first predetermined generally horizontal path extending away from the fixed end of the line such that the length of line between the guide and the load is progressively shortened and the load is thereby hoisted along a second path inclined to the horizontal.

Drawing