GB1567271A - Lifting appliance - Google Patents

Description

(54) LIFTING APPLIANCE (71) We, MIFAGO AKnENGESELL SCHAFr, of Josef Rheinberger Strasse 6, Vaduz/Liechtenstein, a Body Corporate organised under the laws of Liechtenstein, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: This invention relates to a lifting appliance which comprises a pulley block constituted by two mutually adjustable sets of sheaves mounted in a cylinder-like housing, one set of sheaves being axially stationary and rotatably mounted in an intermediate member and the other set of sheaves being adjustably mounted for axial movement in the housing by means of a piston-like component rigidly connected by piston rods to a compressed air-actuated adjusting piston arranged in a cylinder fixed to the intermediate member on the side thereof opposite the adjustable set of sheaves.

Compressed-air-operated lifting appliances of this kind are already known and have proved successful. However, in the known constructions the component carrying the adjustable set of sheaves and the compressedair-actuated piston and also the piston rods connecting these components rigidly together are produced integrally as a casting. Thus the piston rods have to be carried laterally past the intermediate member so that it is difficult or impossible to achieve sealing between the latter and the housing of the component carrying the adjustable set of sheaves and the cylinder. Because such lifting appliances are used more particularly in wet places, such as in car-wash installations, moisture and dirt enters the interior of the lifting appliance on both sides of the intermediate member.The guideways of the moving parts are thereby subjected to a considerable degree of wear and corrode rapidly, so that service breakdowns are virtually unavoidable even after a short service life, and a heavy maintenance outlay involving substantial costs is inevitable.

The invention aims at producing a lifting appliance of the above-defined kind which not only presents the advantages of the known construction, but which furthermore is free from the disadvantages mentioned and is improved to a substantial degree.

Above all it is intended here to ensure that moisture and dirt cannot penetrate into the interior of the lifting appliance even under extreme service conditions, so that said appliance is completely closed and therefore immune to breakdowns and requires no maintenance. It is also aimed at reducing the structural outlay.

To this end, the present invention consists in a lifting appliance, comprising a pulley block constituted by two mutually adjustable sets of sheaves mounted in a cylinder-like housing, one set of sheaves being axially stationary and rotatably mounted in an intermediate member and the other set of sheaves being adjustably mounted for axial movement in the housing by means of a piston-like component rigidly connected by piston rods to a compressed-air-actuated adjusting piston arranged in a cylinder fixed to the intermediate member on the side thereof opposite the adjustable set of sheaves, characterised in that the intermediate member is constructed as an outwardly closed housing part of the lifting appliance, to which the housing accommodating the adjustable set of sheaves of the pulley block, and a cylinder accommodating the adjusting piston, are secured in a fluidtight manner and that the intermediate member is provided with one or more axially parallel bores through which the piston rods, rigidly connecting the adjusting piston to said piston-like component carrying the adjustable set of sheaves are passed.

Conveniently the intermediate member is constructed in the form of a tube section, the end faces of which each have a shoulder to accommodate the housing and the cylinder, and to provide the intermediate member on its exterior envelope surface with a contact surface preferably extending parallel to the axis of the set of sheaves mounted therein.

Furthermore, another contact surface may also be shaped on the intermediate flange opposite the contact surface in the region of the passage of the load cable.

It is further advantageous to machine into the intermediate member in order to guide the piston rods rigidly connecting the adjusting piston to the piston-like component carrying the adjustable set of sheaves, two bores located mutually diametrally opposite which are arranged offset with respect to the axis of the set of sheaves inserted therein, and to construct the piston rods passing through the intermediate member as stay-bolts which are detachably connected by their ends to the adjusting piston and to the component carrying the adjustable set of sheaves, e.g.

are screwed thereto.

A lifting appliance constructed according to the invention not only presents the advantages of the known pneumatically-operated construction of comparable type, namely virtually silent operation, no sparking, infinite adjustability of the load raising and lowering speed and low energy requirements, but it is furthermore ensured by the structural conformation that no moisture and no dirt can enter the interior of the lifting appliance. If in fact the intermediate member is preferably constructed as an outwardly closed housing part, which is adjoined fluidtightly by the further housing parts and in which the piston rods are guided, then it is possible without difficulty to construct the lifting appliance as a totally closed watertight assembly, whilst the operating noise is also damped.

Service breakdowns caused by the penetration of foreign substances are thus eliminated, and the lifting appliance is maintenance-free, because the lubricating media which are applied to the moving parts assembly remain in the appliance and are not washed out. The structural and assembly outlay is also reduced by virtue of the conformation of the intermediate member and of the piston rods. Since no oil drop formation occurs, the lifting appliance according to the invention may be used advantageously virtually everywhere, including more particularly in - medicine and in the foodstuffs and chemical industries.

In order that the invention may be more readily understood, reference is made to the accompanying, drawings which illustrate diagrammatically and by way of example one embodiment thereof, and in which: Fig. 1 is an axial section of the lifting appliance: and Fig. 2 is a section on the line 11-Il of Fig. 1.

The lifting appliance, illustrated in Fig. 1 and designated 1, for raising or lowering a load 3 suspended from a load cable 2 includes a pulley block 11 over which the cable 2 is passed constisting of two sets of sheaves 12 and 13 each constituted by a plurality of individual sheaves 32, and a compressed-air-actuated piston 19 which is rigidly connected~by two piston rods 21 to a member 16 slidably mounted in the housing 15 and carrying the set of sheaves 13 which set is accordingly axially adjustable in the housing. The other set of sheaves 12 is mounted in an intermediate member 14 provided with a rectangular cavity 40 to receive it. The housing 15 is attached to one side of the member 14 and a cylinder 18 for the piston 19 is attached to the other side of the member 14. The housing 15 is closed by a cover 17.

In order to enable the housing 15 and the cylinder 18 to be fixed in fluid-tight manner to the intermediate member 14 in a simple manner, the latter is provided on each of its end faces 23 and 24 with a shoulder 25 or 26, on to which the housing 15 and the cylinder 18 are respectively slid and welded in position. Furthermore, since the two holes 22 located mutually diametrally opposite are machined in the intermediate member 14 to guide the piston rods 21, so that the piston rods 21 pass through the same and not laterally past it, the intermediate member 14 thus constitutes an outwardly closed housing part and the lifting appliance 1 is a completely fluid-tight, closed assembly.The individual parts of the lifting appliance 1 are secured firmly together by means of externally located tie rods 38 which are braced against the cover 17 and against a cover 20 closing the cylinder 18.

In order to suspend the lifting appliance 1, e.g. from a running rail not shown, a surface 27 oriented parallel to the axle 31 carrying the sheaves 32 is provided on the intermediate member 14. The axle 31 is journaled in bore 30 in the member 14 and is secured by a screwthreaded pin 44.

The surface 27 has screwthreaded bores 29 machined in it for screwing on support angles or the like. Opposite to the surface 27 a further surface 28 is provided on the member 14 in which further surface a sleeve 34 is located in a bore 33, through which sleeve the load cable 2 is passed out of the member 14.

When compressed-air is supplied to the pressure chamber 35 of the adjusting piston 19 through a connection 36 in the cover 20, the piston is displaced to the right. Since the member 16- is connected rigidly to the piston by the piston rods 21 constituted as bolts, the set of sheaves 13 mounted rotatable therein in a cavity 45 on an axle 39 is likewise moved to the right so that the load 3 is raised. Meanwhile the interior of the housing 15 is vented through a vent 37.

The piston rods 21 are screwed- to the piston 19 and to the component 16 by means of the screwthreaded attachments 41 and 42 and by a nut 43, so that a simple production of these parts and also a simple assembly are ensured. The lowering of the load 3 is performed by venting the pressure chamber 35.

The lifting appliance 1 is thus a closed, maintenance-free assembly, into which no moisture and no dirt can penetrate and which is suitable for versatile use, particularly since an infinite regulation of the raising or lowering speed of the load can easily be achieved, and virtually no operating noise and no sparking can occur, for a small outlay of energy.

WHAT WE CLAIM IS: - 1. A lifting appliance, comprising a pulley block constituted by two mutually adjustable sets of sheaves mounted in a cylinder-like housing, one set of sheaves being axially stationary and rotatably mounted in an intermediate member and the other set of sheaves being adjustably mounted for axial movement in the housing by means of a piston-like component rigidly connected by piston rods to a compressed-air-actuated adjusting piston arranged in a cylinder fixed to the intermediate member on the side thereof opposite the adjustable set of sheaves, characterised in that the intermediate member is constructed as an outwardly closed housing part of the lifting appliance, to which the housing accommodating the adjustable set of sheaves of the pulley block, and a cylinder accommodating the adjusting piston, are secured in a fluidtight manner and that the intermediate member is provided with one or more axially parallel bores through which the piston rods, rigidly connecting the adjusting piston to said piston-like component carrying the adjustable set of sheaves are passed.

2. Lifting appliance as claimed in claim 1, wherein the intermediate member is constructed in the form of a tube section, the end faces of which are each provided with a shoulder to accommodate the housing and the cylinder.

3. Lifting appliance as claimed in claim 1 or 2, wherein the intermediate member is provided on its external envelope surface with a contact surface preferably orientated parallel to the axis of the set of sheaves mounted therein.

4. Lifting appliance as claimed in claim 3, wherein a further contact surface is provided on the intermediate member opposite the first mentioned contact surface in the region of a guide passage from the load cable.

5. Lifting appliance as claimed in any of the preceding claims, wherein two holes located mutually diametrally opposite which are arranged offset with respect to the axis of the stationary set of sheaves, are machined into the intermediate member in order to guide the piston rods rigidly connecting the adjusting piston to the piston-like component carrying the adjustable set of sheaves.

6. Lifting appliance as claimed in any of the preceding claims, wherein the piston rods are constructed as stay-bolts which are detachably connected by their ends to the adjusting piston and to the piston-like component carrying the adjustable set of sheaves, e.g. are screwed thereto.

7. A lifting appliance substantially as herein described with reference to and as shown in the acocmpanying drawings.

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

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. and by a nut 43, so that a simple production of these parts and also a simple assembly are ensured. The lowering of the load 3 is performed by venting the pressure chamber 35. The lifting appliance 1 is thus a closed, maintenance-free assembly, into which no moisture and no dirt can penetrate and which is suitable for versatile use, particularly since an infinite regulation of the raising or lowering speed of the load can easily be achieved, and virtually no operating noise and no sparking can occur, for a small outlay of energy. WHAT WE CLAIM IS: -

1. A lifting appliance, comprising a pulley block constituted by two mutually adjustable sets of sheaves mounted in a cylinder-like housing, one set of sheaves being axially stationary and rotatably mounted in an intermediate member and the other set of sheaves being adjustably mounted for axial movement in the housing by means of a piston-like component rigidly connected by piston rods to a compressed-air-actuated adjusting piston arranged in a cylinder fixed to the intermediate member on the side thereof opposite the adjustable set of sheaves, characterised in that the intermediate member is constructed as an outwardly closed housing part of the lifting appliance, to which the housing accommodating the adjustable set of sheaves of the pulley block, and a cylinder accommodating the adjusting piston, are secured in a fluidtight manner and that the intermediate member is provided with one or more axially parallel bores through which the piston rods, rigidly connecting the adjusting piston to said piston-like component carrying the adjustable set of sheaves are passed.

2. Lifting appliance as claimed in claim 1, wherein the intermediate member is constructed in the form of a tube section, the end faces of which are each provided with a shoulder to accommodate the housing and the cylinder.

3. Lifting appliance as claimed in claim 1 or 2, wherein the intermediate member is provided on its external envelope surface with a contact surface preferably orientated parallel to the axis of the set of sheaves mounted therein.

4. Lifting appliance as claimed in claim 3, wherein a further contact surface is provided on the intermediate member opposite the first mentioned contact surface in the region of a guide passage from the load cable.

5. Lifting appliance as claimed in any of the preceding claims, wherein two holes located mutually diametrally opposite which are arranged offset with respect to the axis of the stationary set of sheaves, are machined into the intermediate member in order to guide the piston rods rigidly connecting the adjusting piston to the piston-like component carrying the adjustable set of sheaves.

6. Lifting appliance as claimed in any of the preceding claims, wherein the piston rods are constructed as stay-bolts which are detachably connected by their ends to the adjusting piston and to the piston-like component carrying the adjustable set of sheaves, e.g. are screwed thereto.

7. A lifting appliance substantially as herein described with reference to and as shown in the acocmpanying drawings.