GB2091211A

GB2091211A - Lifting gear for e.g. a fork-lift truck

Info

Publication number: GB2091211A
Application number: GB8201172A
Authority: GB
Original assignee: INST ELEKTROKARI MOTOKARI
Current assignee: INST ELEKTROKARI MOTOKARI
Priority date: 1981-01-15
Filing date: 1982-01-15
Publication date: 1982-07-28
Also published as: CS237987B1; GB2091211B; JPS57175699A; IT1147578B; HU185084B; DD230226A3; IT8247551A0; BG34656A1; DE3200287A1; SE8200071L; NL8200131A; FR2497785B3; FR2497785A1

Abstract

Lifting gear, for example for a fork-lift truck, comprises upper and lower telescoping mast assemblies (4, 3) which are displaceable relatively to each other by hydraulic lifting means to raise and lower a lifting carriage through the intermediary of a pulley/ chain mechanism (23, 2). Each mast assembly comprises two upwardly extending members (5 or 12) which are interconnected, by members (13), or (7) and (8), at the ends away from the other mast assembly. This leaves the central part of the mast assembly unobstructed, providing good visibility to an operator. Visibility is also enhanced by forming the members (5) of the lower assembly (3) with cylindrical portions (10), (Figure 6) which accommodate the lifting means. <IMAGE>

Description

SPECIFICTION Lifting gear This invention relates to lifting gear, particuiarly, although not exclusively lifting gear for battery and engine powered fork lift trucks, loaders, tractors and other types of mechanical handling equipment.

Known lifting gear for a fork lift truck comprises an outer mast and an inner mast. A lifting carriage is movably supported on the inner mast by elongate flexible elements such as chains passing over rollers carried by the inner mast. One end of each chain is fastened to the carriage and the other to the outer mast. Two hydraulic lifting units are connected with mast sections and are mounted by the mast columns. The outer and inner masts both comprise closed frame structures.

A major disadvantage of this known design is that the field of vision of the truck driver is reduced by the breadth of the section columns from which the masts are made, by the hydraulic lifting assemblies and by the presence of cross beams which interconnect the vertical parts of the masts. The large number of components such as hydraulic cylinders, columns and cross beams makes upright arrangement and fitting of the components to each other more complex and increases structure weight.

According to the present invention there is provided lifting gear comprising a mast made up of two mast assemblies which are displaceable relatively to each other by hydraulic lifting means to change the height of the mast, one of the mast assemblies comprising two upwardly extending members which are interconnected at their lower regions, at least one of the members providing a housing accommodating part of the lifting means, the other mast assembly comprising two upwardly extending members which are interconnected at their upper regions and are provided at their upper regions with pulleys over which extend elongate flexible eiements, one end of each elongate flexible element being fastened to the said one mast assembly and the other being fastened to a lifting carriage of the lifting gear.

An embodiment of a fork lift truck having lifting gear in accordance with the present invention has the following advantages over the prior art construction discussed above: - increased truck driver field of vision through the lifting gear as a result of the combining of the members of the said one mast assembly with the hydraulic lifting means; - fewer mast components and - lowered lifting gear mass.

For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a rear perspective view of lifting gear for a fork lift truck; Figure 2 is a sectional view taken on the line ll-ll of Figure 1, Figure 3 is a fragmentary perspective front view of the lifting gear shown in Figure 1; Figure 4 is a sectional view taken on the line IV-IV of Figure 3; Figure 5 is a diagrammatic rear view of the lifting gear of Figures 1 to 4; Figure 6 is a cross-section of a component of the lifting gear of Figures 1 to 5; and Figure 7 is an alternative cross-section for the component of Figure 6.

The lifting gear shown in Figures 1 to 5 comprises a lifting carriage 1, chains 2, an outer mast assembly 3 and an inner mast assembly 4.

The outer mast assembly 3 comprises two upright guide members 5, which provide housings 24 of hydraulic lifting assemblies, and transverse crossmembers 7 and 8 interconnecting the lower parts of the guide members 5. The cross-section of each guide member comprises a cylindrical part 10 connected to a channel-shaped part 11 (Figure 6).

The housing 24 of each guide member 5 envelops a lifting member 6 of the respective hydraulic lifting assembly. The cross-member 7 is hollow and is used to convey fluid under pressure from a pipe 9 to the hydraulic lifting assemblies.

The inner mast assembly 4 comprises two members 12 which are interconnected attheirtop ends by a cross-member 13. The inner mast assembly 4 is connected to the lifting members 6 by brackets 20.

The guide members 5 of the outer mast assembly 3 support attheirtop end regions rollers 14 acting on the members 12 in the directions indicated by arrows C, and rollers 15 for lateral guidance, acting on the members 12 in the directions indicated by arrows Aa and Ab. Guide brackets 16 act on the members 12 in the directions indicated by arrows Ba and Bb.

The members 12 of the inner mast assembly 4 support at their lower end regions rollers 17 acting on the guide members 5 in direction C, rollers 18 for lateral guidance acting on the guide members 5 in directions Ba and Bb, and guide brackets 19 acting on the guide members 5 in directions Aa and Ab.

Each chain 2 is connected at one end to the lifting carriage 1 by mountings 21 and at the other end to the outer mast assembly by mountings 22, passing over pulleys 23 supported on pins fixed to the inner mast 4.

The field of vision for the truck driver through the lifting gear is indicated by the shaded area B in Figure 5. This area is limited in height by the upper cross-member 13 and the lower cross-member 7.

The field of vision B is limited in breadth by the columns comprising the members 5 and 12.

The lifting gearfunctions as follows; fluid under pressure is supplied through the pipe 9 and crossmember 7 to the housings 24 of the hydraulic lifting assemblies. This raises the lifting members 6 and thus the inner mast assembly 4. The movement of the inner mast 4 also lifts the fork carriage 1 by means of the chains 2 passing over the pullleys 23.

1. Lifting gear comprising a mast made up of two mast assemblies which are displaceable relatively to each other by hydraulic lifting means to change the

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICTION Lifting gear This invention relates to lifting gear, particuiarly, although not exclusively lifting gear for battery and engine powered fork lift trucks, loaders, tractors and other types of mechanical handling equipment. Known lifting gear for a fork lift truck comprises an outer mast and an inner mast. A lifting carriage is movably supported on the inner mast by elongate flexible elements such as chains passing over rollers carried by the inner mast. One end of each chain is fastened to the carriage and the other to the outer mast. Two hydraulic lifting units are connected with mast sections and are mounted by the mast columns. The outer and inner masts both comprise closed frame structures. A major disadvantage of this known design is that the field of vision of the truck driver is reduced by the breadth of the section columns from which the masts are made, by the hydraulic lifting assemblies and by the presence of cross beams which interconnect the vertical parts of the masts. The large number of components such as hydraulic cylinders, columns and cross beams makes upright arrangement and fitting of the components to each other more complex and increases structure weight. According to the present invention there is provided lifting gear comprising a mast made up of two mast assemblies which are displaceable relatively to each other by hydraulic lifting means to change the height of the mast, one of the mast assemblies comprising two upwardly extending members which are interconnected at their lower regions, at least one of the members providing a housing accommodating part of the lifting means, the other mast assembly comprising two upwardly extending members which are interconnected at their upper regions and are provided at their upper regions with pulleys over which extend elongate flexible eiements, one end of each elongate flexible element being fastened to the said one mast assembly and the other being fastened to a lifting carriage of the lifting gear. An embodiment of a fork lift truck having lifting gear in accordance with the present invention has the following advantages over the prior art construction discussed above: - increased truck driver field of vision through the lifting gear as a result of the combining of the members of the said one mast assembly with the hydraulic lifting means; - fewer mast components and - lowered lifting gear mass. For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a rear perspective view of lifting gear for a fork lift truck; Figure 2 is a sectional view taken on the line ll-ll of Figure 1, Figure 3 is a fragmentary perspective front view of the lifting gear shown in Figure 1; Figure 4 is a sectional view taken on the line IV-IV of Figure 3; Figure 5 is a diagrammatic rear view of the lifting gear of Figures 1 to 4; Figure 6 is a cross-section of a component of the lifting gear of Figures 1 to 5; and Figure 7 is an alternative cross-section for the component of Figure 6. The lifting gear shown in Figures 1 to 5 comprises a lifting carriage 1, chains 2, an outer mast assembly 3 and an inner mast assembly 4. The outer mast assembly 3 comprises two upright guide members 5, which provide housings 24 of hydraulic lifting assemblies, and transverse crossmembers 7 and 8 interconnecting the lower parts of the guide members 5. The cross-section of each guide member comprises a cylindrical part 10 connected to a channel-shaped part 11 (Figure 6). The housing 24 of each guide member 5 envelops a lifting member 6 of the respective hydraulic lifting assembly. The cross-member 7 is hollow and is used to convey fluid under pressure from a pipe 9 to the hydraulic lifting assemblies. The inner mast assembly 4 comprises two members 12 which are interconnected attheirtop ends by a cross-member 13. The inner mast assembly 4 is connected to the lifting members 6 by brackets 20. The guide members 5 of the outer mast assembly 3 support attheirtop end regions rollers 14 acting on the members 12 in the directions indicated by arrows C, and rollers 15 for lateral guidance, acting on the members 12 in the directions indicated by arrows Aa and Ab. Guide brackets 16 act on the members 12 in the directions indicated by arrows Ba and Bb. The members 12 of the inner mast assembly 4 support at their lower end regions rollers 17 acting on the guide members 5 in direction C, rollers 18 for lateral guidance acting on the guide members 5 in directions Ba and Bb, and guide brackets 19 acting on the guide members 5 in directions Aa and Ab. Each chain 2 is connected at one end to the lifting carriage 1 by mountings 21 and at the other end to the outer mast assembly by mountings 22, passing over pulleys 23 supported on pins fixed to the inner mast 4. The field of vision for the truck driver through the lifting gear is indicated by the shaded area B in Figure 5. This area is limited in height by the upper cross-member 13 and the lower cross-member 7. The field of vision B is limited in breadth by the columns comprising the members 5 and 12. The lifting gearfunctions as follows; fluid under pressure is supplied through the pipe 9 and crossmember 7 to the housings 24 of the hydraulic lifting assemblies. This raises the lifting members 6 and thus the inner mast assembly 4. The movement of the inner mast 4 also lifts the fork carriage 1 by means of the chains 2 passing over the pullleys 23. CLAIMS

1. Lifting gear comprising a mast made up of two mast assemblies which are displaceable relatively to each other by hydraulic lifting means to change the height of the mast, one of the mast assemblies comprising two upwardly extending members which are interconnected at their lower regions, at least one of the members providing a housing accommodating part of the lifting means, the other mast assembly comprising two upwardly extending members which are interconnected at their upper regions and are provided at their upper regions with pulleys over which extend elongate flexible elements, one end of each elongate flexible element being fastened to the said one mast assembly and the other being fastened to a lifting carriage of the lifting gear.

2. Lifting gear as claimed in claim 1, in which the members of the said one mast assembly are interconnected at their lower regions buy a cross-member which serves as a duct for supplying hydraulic fluid to the lifting means.

3. Lifting gear as claimed in claim 1 or 2, in which guide means are provided at the upper regions of the members of the said one mast assembly and at the lower regions of the members of the said other mast assembly for guiding the mast assemblies with respect to each other.

4. Lifting gear as claimed in any one of the preceding claims, in which each member of the said one mast assembly comprises a cylindrical portion, providing the housing, and a channel-shaped portion.

5. Lifting gear as claimed in claim 4, in which the cylindrical portion of each member is disposed on the side of that member away from the other member.

6. Lifting gear substantially as described herein with reference to, and as shown in, Figures 1 to 6, or Figures 1 to 6 as modified by Figure 7, of the accompanying drawings.

7. Mechanical handling equipment having lifting gear in accordance with any one of the preceding claims.