GB2030542A

GB2030542A - Sideways shifter for lift truck forks

Info

Publication number: GB2030542A
Application number: GB7910309A
Authority: GB
Original assignee: Costruzioni Meccaniche Bolzoni SpA
Current assignee: Costruzioni Meccaniche Bolzoni SpA
Priority date: 1978-09-29
Filing date: 1979-03-23
Publication date: 1980-04-10
Also published as: ES480005A1; DE7907954U1; GB2030542B; IT7822923V0; FR2437374A3; FR2437374B3

Abstract

This invention relates to a shifter for lift trucks. The shifter comprises an elongated guide 10 for coupling to the upper edge of a fork support plate 11 of the lift truck. A mobile plate 16 is mounted on said guide through self- lubricating sliding bearings 13 with cylindrical friction surfaces. Said mobile plate lowerly comprises self-lubricating flat shoes 17, which rest against the lift truck plate 11. A control jack 23 is interposed between the mobile plate 16 and an arm 2 extending from the guide 10. <IMAGE>

Description

SPECIFICATION Sideways shifter for lift truck forks It is known to mount the forks or equivalent pickup members on the plate of lift trucks by way of devices which enable the forks to be shifted sideways so as to facilitate the pickup and depositing of the loads.

These devices must satisfy many requirements for their characteristics to be acceptable. In this respect, they must be of small thickness as they necessarily increase, by their own thickness, the amount by which the load projects so increasing the overturning moment on the truck. In this respect therefore, even a reduction in the thickness of the device by a few centimetres can constitute considerable technical progress, if other characteristics are equal.

In the same way, it is obviously desirable for the device to possess the necessary strength for minimum weight, this latter always negatively influencing the useful truck load and making the assembly and removal of the device more laborious. To obtain a iightweight shifter which at the same time is sufficiently strong, various configuration arrangements are necessary with the object of improving utilisation of the material and of the individual parts of the device in supporting the forces concerned.

Another not indifferent problem is to ensure good sliding between the moving parts such that it is not subject to alteration with time or because of adverse environmental conditions under which the device may be required to operate.

The object of the present invention is to provide a shifter which possesses many improved characteristics over those of similar conventional devices.

To this end, the invention provides a shifter for lift trucks, comprising an elongate guide for coupling to the upper edge of a fork support plate of a lift truck, and on which are mounted self-lubricating sliding bearings with cylindrical friction surfaces, and on which rests a channel support of corresponding profile, with which the mobile plate is rigid, said mobile plate lowerly comprising self-lubricating flat shoes which rest at their front against the lift truck plate, an arm extending from the guide and having pivoted thereto the end of a control jack which is pivoted at its other end to the mobile plate.

The objects and characteristics of the invention will be more apparent from the description given hereinafter by way of example of one embodiment illustrated in the accompanying drawings in which: Figure 1 is a front view of the device, Figure 2 is a side view, Figure 3 is a partial section on the line Ill-Ill of Figure 1.

The shifter according to the invention comprises a guide 10 which is coupled to the upper edge of a conventional fork support plate 11 of a lift truck. It has a lower profile arranged to displace said upper edge of the plate, and comprises a central tooth 12 which seats in a corresponding cavity in the plate 11, so that it cannot translate.

At its top, the guide 10 is of rounded shape, and slide shoes 13 rest thereon, they being constrained to the guide bytheirtooth 14 seating in corresponding cavities.

A curved section 15 to which the mobile piate 16 is welded, rests on these shoes. The plate 16 is formed from two bars 26 and 27 connected together by cross members 25. Two slide shoes 17 are provided below the plate 16, i.e. on the bar 27, and rest against the front of the plate 11 of the lift truck, they being supported by blocks 18, on the extension of which are bolted hooks 19 which grip the lower edge of the plate 11 with some slack.

The mobile plate 16 has an external profile analogous to the plate 11, so that a conventional fitting partly shown at 20 can be hooked over it, this fitting being of the type that can be received directly by the plate 11. Stops 28 are provided for defining the lateral position of the fitting.

To the guide 10 there is fixed an appendix 21, to which a jack 23 is pivoted at 22, the other end of the jack being pivoted at 24 to a cross member 25 of the plate 16.

The jack 23 is disposed in such a manner that its line of action coincides substantially with the resultant of the sliding forces on the shoes 13 and 17, so that no jamming couples arise during the sideways sliding of the shifter.

It has proved advantageous to use a jack 23 of the monobloc head type, to give the maximum useful bore for the maximum outerdiamensions.

The shifter according to the invention has many advantages, and these are summarised hereinafter.

The bent configuration of the upper edge 15 of the shifting slide is both highly effective as a support and a shifter guide, and also constitutes a protection for the support for the shoes 13 because of its enclosing structure. For this purpose, it is advantageous if its length is such as to coverthe shoes over the entire required transverse stroke.

The shoes 17, which have scraper edges, prevent any infiltration of dust, sand or abrasive particles which could damage the friction surfaces and in particular increase the sliding resistance of the shifter.

The general configuration of the shifter is such that it is of minimum overall size, and in particular projects to a surprisingly low degree above the line of the lift truck plate, and has a thickness and total weight which are very small in comparison with similar conventional devices.

It should also be noted that with the shifter configuration proposed by the invention, it is very simple to fit the shifter to a lift truck plate.

To do this, it is necessary only to hook the shifter over the upper edge of the plate and then screw down the lower hooks 19 to fix the shifter on to the lift truck in a stable and reliable manner. Bores, threads or welds of any kind are not required.

In accordance with the objects of the invention, all this provides a light shifter having a small degree of projection, which does not limit the visibility of the operator, is easy to assemble and remove, and is highly reliable.

1. Ashifterfor lift trucks, comprising an elon

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Sideways shifter for lift truck forks It is known to mount the forks or equivalent pickup members on the plate of lift trucks by way of devices which enable the forks to be shifted sideways so as to facilitate the pickup and depositing of the loads. These devices must satisfy many requirements for their characteristics to be acceptable. In this respect, they must be of small thickness as they necessarily increase, by their own thickness, the amount by which the load projects so increasing the overturning moment on the truck. In this respect therefore, even a reduction in the thickness of the device by a few centimetres can constitute considerable technical progress, if other characteristics are equal. In the same way, it is obviously desirable for the device to possess the necessary strength for minimum weight, this latter always negatively influencing the useful truck load and making the assembly and removal of the device more laborious. To obtain a iightweight shifter which at the same time is sufficiently strong, various configuration arrangements are necessary with the object of improving utilisation of the material and of the individual parts of the device in supporting the forces concerned. Another not indifferent problem is to ensure good sliding between the moving parts such that it is not subject to alteration with time or because of adverse environmental conditions under which the device may be required to operate. The object of the present invention is to provide a shifter which possesses many improved characteristics over those of similar conventional devices. To this end, the invention provides a shifter for lift trucks, comprising an elongate guide for coupling to the upper edge of a fork support plate of a lift truck, and on which are mounted self-lubricating sliding bearings with cylindrical friction surfaces, and on which rests a channel support of corresponding profile, with which the mobile plate is rigid, said mobile plate lowerly comprising self-lubricating flat shoes which rest at their front against the lift truck plate, an arm extending from the guide and having pivoted thereto the end of a control jack which is pivoted at its other end to the mobile plate. The objects and characteristics of the invention will be more apparent from the description given hereinafter by way of example of one embodiment illustrated in the accompanying drawings in which: Figure 1 is a front view of the device, Figure 2 is a side view, Figure 3 is a partial section on the line Ill-Ill of Figure 1. The shifter according to the invention comprises a guide 10 which is coupled to the upper edge of a conventional fork support plate 11 of a lift truck. It has a lower profile arranged to displace said upper edge of the plate, and comprises a central tooth 12 which seats in a corresponding cavity in the plate 11, so that it cannot translate. At its top, the guide 10 is of rounded shape, and slide shoes 13 rest thereon, they being constrained to the guide bytheirtooth 14 seating in corresponding cavities. A curved section 15 to which the mobile piate 16 is welded, rests on these shoes. The plate 16 is formed from two bars 26 and 27 connected together by cross members 25. Two slide shoes 17 are provided below the plate 16, i.e. on the bar 27, and rest against the front of the plate 11 of the lift truck, they being supported by blocks 18, on the extension of which are bolted hooks 19 which grip the lower edge of the plate 11 with some slack. The mobile plate 16 has an external profile analogous to the plate 11, so that a conventional fitting partly shown at 20 can be hooked over it, this fitting being of the type that can be received directly by the plate 11. Stops 28 are provided for defining the lateral position of the fitting. To the guide 10 there is fixed an appendix 21, to which a jack 23 is pivoted at 22, the other end of the jack being pivoted at 24 to a cross member 25 of the plate 16. The jack 23 is disposed in such a manner that its line of action coincides substantially with the resultant of the sliding forces on the shoes 13 and 17, so that no jamming couples arise during the sideways sliding of the shifter. It has proved advantageous to use a jack 23 of the monobloc head type, to give the maximum useful bore for the maximum outerdiamensions. The shifter according to the invention has many advantages, and these are summarised hereinafter. The bent configuration of the upper edge 15 of the shifting slide is both highly effective as a support and a shifter guide, and also constitutes a protection for the support for the shoes 13 because of its enclosing structure. For this purpose, it is advantageous if its length is such as to coverthe shoes over the entire required transverse stroke. The shoes 17, which have scraper edges, prevent any infiltration of dust, sand or abrasive particles which could damage the friction surfaces and in particular increase the sliding resistance of the shifter. The general configuration of the shifter is such that it is of minimum overall size, and in particular projects to a surprisingly low degree above the line of the lift truck plate, and has a thickness and total weight which are very small in comparison with similar conventional devices. It should also be noted that with the shifter configuration proposed by the invention, it is very simple to fit the shifter to a lift truck plate. To do this, it is necessary only to hook the shifter over the upper edge of the plate and then screw down the lower hooks 19 to fix the shifter on to the lift truck in a stable and reliable manner. Bores, threads or welds of any kind are not required. In accordance with the objects of the invention, all this provides a light shifter having a small degree of projection, which does not limit the visibility of the operator, is easy to assemble and remove, and is highly reliable. CLAIMS

1. Ashifterfor lift trucks, comprising an elon gated guide for coupling to the upper edge of a fork support plate of a lift truck, and on which are mounted self-lubricating sliding bearings with cylindrical friction surfaces, and on which rests a channel support of corresponding profile, with which the mobile plate is rigid, said mobile plate lowerly comprising self-lubricating flat shoes which rest at their front against the lift truck plate, an arm extending from the guide and having pivoted thereto the end of a control jack which is pivoted at its other end to the mobile plate.

2. A shifter as claimed in claim 1, wherein said elongated guide upperly comprises notches which receive complementary surfaces of the sliding bearings.

3. A shifter as claimed in claim 1, characterised in that the channel support extends laterally beyond the bearings, on which it rests over a distance not less than half the sideways stroke of the shifter, so that the bearings do not become uncovered during the stroke of the shifter.

4. A shifter as claimed in claim 1, wherein the lower flat shoes are of the scraping edge type to prevent any foreign material becoming wedged between the friction surfaces.

5. A shifter as claimed in claim 1, characterised in that the shifter plate is constituted by two horizontal bars of small height, joined together by vertical cross members.

6. A shifter as claimed in claim 1, wherein the jack is of the monobloc head type so as to provide a high ratio between the useful bore and the outer dimensions.

7. A shifter as claimed in claim 1,wherein hooks are removably mounted on the shifter plate for slackly hooking to the lower edge of the lift truck plate.

8. A shifter as claimed in claim 7, and mounted on the lift truck plate by simply hooking the upper guide on to the upper edge of said plate, and is kept in this position by the hooks which slackly grip the lower edge of said plate.

9. A shifter as claimed in claim 1, wherein the line of action of the jack substantially coincides with the line of action of the resultant of the friction forces on the sliding surfaces of the shifter plate.

10. A shifter as claimed in one or more of the preceding claims, substantially as heretofore described and illustrated on the accompanying drawings.

11. A device for laterally shifting a load-carrying part of a lift truck comprising an elongate guide for mounting on the upper edge of a fork support plate of a lift truck, self-lubricating slide bearings mounted on the guide and having arcuate-section upper bearing surfaces, a laterally movable upright plate through which in use the load is applied to the truck, a channel-shaped support secured to the movable plate and resting on the slide bearings, and selflubricating flat shoes on the lower part of the movable plate for resting against the fork support plate of the truck, the guide and the movable plate being interconnected through a control jack.

12. A fork lift truck incorporating a device according to any preceding claim.