GB2104860A

GB2104860A - Load supporting unit

Info

Publication number: GB2104860A
Application number: GB08126506A
Authority: GB
Inventors: Sven Runo Vilhelm Gebelius
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-09-01
Filing date: 1981-09-01
Publication date: 1983-03-16
Also published as: GB2104860B

Abstract

A device for a pallet to facilitate movement over a supporting surface has a piston (2), arranged to move in a direction towards the supporting surface, and having a recess (4) open in a direction towards the supporting surface with a spherical supporting member (5) located in said recess (4) and movable in relation to the piston (2) to a position extending out from the piston (2). A channel (8) communicates between the recess (4) and the other end of the piston and an inlet (3) connected to a gas source under pressure supplies gas to the other end of the piston (2) to move the piston (2) and/or the supporting member (5) to a position in which the support member (5) contacts the supporting surface. In this position the gas is arranged to flow past the support member (5) while maintaining an increased pressure in the recess (4), thus lifting the load carrying unit from the supporting surface. <IMAGE>

Description

SPECIFICATION Device for load supporting unit This invention relates to a device for a load supporting unit, e.g. pallets used to support goods during transport and storage. The term "load supporting unit" also includes other types of devices, e.g. units used to support articles during manufacture, which articles are to be moved between various assembly, control or test stations when manufactured. Also other types of load carrying units are included, intended to facilitate transport of a supported load.

With regard to pallets and similar types of load carrying units, a transport operation, e.g. from a storage area to another location or to a transport vehicle, is carried out by means of a suitable lifting device, such as a fork lift truck, manually movable hydraulically operable lifting devices, or similar. Especially for short transport distances, manually movable lifting devices are used, e.g. for transport operations on vehicles or for short transports within a warehouse or similar. As a result, suitable devices must usually be carried on each vehicle, and corresponding devices must also be available in required number within the premises where transport is to be carried out.

With regard to load supporting units used for mass production same must either be arranged on a suitable conveyor, such as a conveyor belt or a roller conveyor, or the units may also be moved between the manufacturing stations by means of an air cushion, i.e. compressed air is supplied to each unit and directed towards the floor surface by means of nozzles, whereby the air jets directed towards the floor surface accomplish a lifting effect, intended to facilitate transport of the unit from one station to another.

An object of this invention is to provide a device, which can be used for various types of load carrying units, and which facilitates movement of a unit without need for any transport devices. The device is particularly suitable for short distance transport, e.g. within premises, on vehicles when loading/unloading, or similar applications. The movement is achieved by application of a small manual force. The device according to the invention uses compressed air, from a small container located in the load carrying unit, but as air consumption during a transport movement is considerably lower than previously known devices of the air cushion type, a small volume only of air is needed for iong distances, or repeated short distances.

According to this invention there is provided a device for a load carrying unit to facilitate movement of the load carrying unit over a support surface by application of force in the required direction of travel, the device comprising a piston movable in a cylinder towards the support surface, the piston having a recess open towards the support surface and surrounding a spherical support member, an inlet being arranged to communicate with a pressure gas source and arranged to supply gas to an end of the piston opposite the end housing the support member which member is arranged to be movable in the recess, a channel communicating between the recess and the end of the piston adjacent the inlet, the spherical support member being arranged to move to a position extending partly outside the end surface of the piston, supply of gas to the inlet member being arranged to cause movement of the piston and/or the support member to provide contact between the support member and the supporting surface, the gas flowing past the support member in said position, whereby the gas flow cushions the supporting member from contact with a surrounding wall portion of the recess.

A number of embodiments according to the present invention are more fully described below as examples and with reference being made to the accompanying drawings, wherein: Figure 1 shows a cross-sectional view of a first embodiment of a device according to the invention and in a first position, Figure 2 shows a cross-sectional view corresponding to Figure 1, with the device in a second position, Figure 3 shows a cross-sectional view of a modified embodiment of the device according to the present invention, and Figure 4 shows a perspective view of a load carrying unit, having a number of devices according to the invention.

With reference to the embodiment shown in Figures 1 and 2, this comprises a cylindrical housing 1, in which a piston member 2 is arranged to be slidable a limited distance. The housing 1 includes an inlet coupling 3, communicating with a compressed air source.

From the end surface of the piston member 2 opposite the inlet 3, is a part spherical cavity 4 extending into the piston 2 and surrounding a spherical support member 5. A flat abutment member 6 is attached to the end surface of the piston 2 and the aperture in the abutment member 6 has a diameter smaller than the diameter of the spherical member 5, which thus is held in a position substantially completely surrounded by the recess 4. From the end surface of the piston member 2 directed toward the inlet 3, a boring 7 extends in a direction towards the recess 4 and leads to a channel 8, having conically flared end portions, which serve as valve seats for a longitudinally extending poppet valve 9, extending through the channel 8.

The embodiment described is attached to a load carrying unit, e.g. as indicated in Figure 4, which shows a pallet 10, as a complete unit having fixed facing towards the floor surface supporting members 11, 1 1'. In each of the supporting members 11, 11' is a device of the type described with reference to Figures 1 and 2 and arranged, with an inlet 3 attached to a pipe system 12 connected to a compressed air container 13, arranged with a flow restricting valve 14. Each device is attached to the supporting members 11, 11' in such a way, that the spherical ball-shaped supporting member 5 is directed towards the floor on which the load carrying unit 10 is arranged.

When the valve member 14 is not operated, that is when compressed air is not supplied to the inlets 3 each device takes up a first position as shown in Figure 1, i.e. the load carrying unit 10 is resting in a conventional way on the floor through the free end surface of the support members 11, 11'.

When it is desired to move the load carrying unit 10, the valve member 14 is operated, whereby compressed air is supplied to each unit from the compressed air container 1 3 via the pipe system 12, connected with the inlets 3 of each device. As a result, the compressed air flows through the boring 7 via channel 8 into the recess 4, whereby under the load carrying unit 10. When this movement takes place, two alternative results may be accomplished.

If the supporting surface comprises of a completely flat floor surface, located immediately under the end surface of the support member 11, 11' surrounding a device, the spherical ballshaped member 5 takes up contact with the supporting surface in a position mainly corresponding to the first position shown in Figure 1, and the supplied compressed air flows past the spherical member 5 in the small surrounding air passage, formed in connection with the member 6.The air pressure acting on the upper portion of the spherical ball-shaped supporting member 5 thus causes a lifting movement for the load carrying unit 10, whereby the member 5, due to the surrounding flowing air, does not take up mechanical contact with surrounding parts, i.e. said supporting member 5 is arranged in a mainly non-frictional condition in relation to surrounding parts. The load carrying unit 10 can thus be moved by application of an extremely small manual force.

An alternative result can also be achieved, when the valve 14 is operated and during a transport movement where the floor surface has smaller irregularities. When the first sliding movement in relation to the piston 1 of the supporting member 5 does not cause the supporting member 5 to take up contact with the floor surface the sliding movement is effected until the portion of the valve 9 adjacent the inlet 3 makes contact with the valve seat in the channel 8, whereby air is no longer supplied to the recess 4, but only to the boring 7 and adjacent end portion of the piston member 2. As a result, the piston member 2 is moved in direction towards the floor surface to a position in which the spherical ball-shaped supporting member 5 makes contact with the supporting surface.Since the spherical member 5 at the moment of contact is not under the influence of any lifting force, caused by compressed air supplied to the recess 4, a continued sliding movement of the piston 2 causes the spherical member to contact the valve member 9, which is moved from sealing contact against the valve seat adjacent to the inlet 3, whereby compressed air is supplied to the recess 4 through the channel 8. As a result, a lifting position is achieved, in which the spherical ballshaped supporting member takes up a mainly non-frictional condition as described before.

During a transport movement, said piston member 2 thus takes up various relative positions in relation to the surround housing 1, in order to adjust to irregularities in the supporting surface.

However, a further position may also exist, apart from the position in which the piston member 2 facilitates transport movement in that the spherical member 5 makes contact with a supporting surface. This condition can also result when the load carrying unit 10 for example is to be moved over a supporting surface having a deep hole or groove, in which case it is advantageous to prevent air leakage from the device. As shown in Figure 2, such a leakage is prevented partly because of the valve member 9 making contact against the valve seat in the channel 8 directed towards the inlet 3, partly due to the fact that the spherical ball-shaped supporting member 5 makes contact against the member 6. Here air leakage is completely eliminated from a device when, for any reason, it does not contact a supporting surface.

If a spherical member 5 during a transport movement for any reason should be made subject to a sudden force, e.g. when passing a door sill or similar, the member 5 can obviously be rapidly moved in a direction towards the bottom portion of the recess 4, and such a movement is only for a short period of time, causing the surrounding air passage to be enlarged with excessive air leakage. However, this leakage is reduced due to the fact that the valve 9 can also make sealing contact against the valve seat in the channel 8 and directed towards the semi-spherical recess 4, whereby air supply to said recess is intermittently interrupted, which also causes a reduced air consumption.

In the above described embodiment, the recess 4, which surrounds the spherical supporting member, has been described es semi-spherical. In view of the fact that such a design from manufacturing point of view is often costly and not preferred, Figure 3 shows an example of a modified embodiment. This embodiment has basically correspondingly arranged parts to the above described embodiment, but the recess 4 is arranged as a cylindrical recess, and the abutment member 6 is thicker, having the internal edge portion of the centrally located aperture arranged with a radius adapted to the spherical supporting member 5. According to this embodiment, an air passage is provided when compressed air is supplied which surrounds the spherical supporting member 5 by the cylindrical wall surface of the recess 4, and also between the spherical supporting member 5 and the centrally located apertures in the abutment member 6. The operation of this embodiment is as disclosed with reference to previous embodiments.

During a transport movement, when the spherical member 5 is rolling on a support surface, a side force may be imposed on the valve member 9, caused by friction between the part of the valve member 9 which is in contact with the spherical supporting member 5 and the outer surface of the member. Such a force exists, if the axis of the valve member 9 corresponds with the centre of the spherical member 5. However, this problem can be overcome in various ways, e.g. by making the contact surface of the valve member 9 curved, in order to reduce the size of the contact surface, or by covering said contact surface with a suitable friction reducing material.A preferred alternative is, to move the centre of the axis of the valve member 9 in relation to the centre of rotation of the spherical member 5, whereby a rotary movement of the supporting member 5 is transformed into a rotary movement of the valve member 9, thus the previously discussed side force is transformed into a rotary force acting on the valve member 9.

As previously mentioned, there is no air leakage in thosecases when the support member 5 does not make contact with a supporting surface, partly due to the valve member 9, partly due to the contact of the spherical supporting member 5 against the member 6. The seal between the member 5 and the member 6 can be further improved, if the portidn of the member 6 which is in contact with the spherical supporting member 5 is arranged with a layer of suitable flexible sealing material, such as rubber, synthetic plastics or the like.- It should also be mentioned, that the above double sealing is based on the fact that the valve member 9 in the closed position no longer takes up direct contact with the support member 5.

In a modification the piston member 2 can be formed as a unit comprising two members, which are joined in a position surrounding the support member 5. The abutment member can be excluded, since the cavity 4 can be arranged with such a shape, that member 6 is replaced. The piston 2 is arranged to move a restricted distance in the surrounding housing 1. In the described and shown embodiment this is accomplished by arranging the piston 2 with two different diameters, defining a first guiding and sealing portion, and a second part of a smaller diameter, and the surface between said diameters being used as a movement restricting member in connection with a co-acting abutment surface in the housing 1.

A corresponding restriction of movement can be achieved by using other known means, whereby it would be possible to arrange the piston 2 with a uniform external diameter, thus manufacturing - costs can be reduced. The housing 1 can also be an integrated part of the unit in which the device is arranged, preferably arranges as a cylinder, in which the piston 2 can move a restricted distance. For applications where a low air consumption is not of importance, the valve member 9 can be excluded whereby sealing is only achieved at the lower edge portion of the recess 6 surrounding the support member 5. It should also be mentioned, that compressed air obviously can be supplied in ways other than from a container 13, located on the load carrying unit 10. Accordingly, compressed air can be supplied to the load carrying unit 10 by means of a hose connected to an available compressed air source.

Claims

1. A device for a load carrying unit to facilitate movement of the load carrying unit over a support surface by application of force in the required direction of travel, the device comprising a piston movable in a cylinder towards the support surface, the piston having a recess open towards the support surface and surrounding a spherical support member, an inlet being arranged to communicate with a pressure gas source and arranged to supply gas to an end of the piston adjacent the inlet, the spherical support member being arranged to move to a position extending partly outside the end surface of the piston, supply of gas to the inlet member being arranged to cause movement of the piston and/or the support member to provide contact between the support member and the supporting surface, the gas flowing past the support member in said position, whereby the gas flow cushions the supporting member from contact with a surrounding wall portion of the recess.

2. A device according to Claim 1, wherein a longitudinally extending valve member is arranged in the channel and arranged to close said channel from communication with the inlet when the supporting member extends from the piston member a maximum distance.

3. A device according to Claim 1 or 2, wherein the recess in the piston member surrounding the supporting member is part spherical.

4. A device according to Claim 1 or 2, wherein the recess in the piston member surrounding the supporting member is cylindrical.

5. A device according to any preceding claim, wherein the recess at the open end has a circular cross-sectional being smaller than the diameter of the supporting member.

6. A device according to Claim 5, wherein the recess end is defined by an abutment member secured to the piston member and having a centrally located apparatus.

7. A device according to Claim 6, wherein said aperture is arranged with an edge to make contact with the supporting member, having a shape corresponding to the shape of the support member.

8. A device according to Claims 1 and 2, wherein the valve member is arranged to make sealing contact against a co-acting valve seat in the channel, when the support member is located in an inward limit position away from the open portion of the recess.

9. A device according to any preceding claim, wherein the abutment portion which restricts movement of the supporting member in a direction out from the piston is arranged with a sealing means to engage said member.

1 0. A device according to any preceding Claims 1 or 2, wherein the axis of the valve member is displaced in relation to an axis extending through the centre of the support member.

11. A device substantially as described herein and with reference to the accompanying drawings.