DE3318087A1 - Elevating platform - Google Patents

Description

Menges & Prahl

Professional representatives before the European Patent Office

Erhardtstrasse 12, D-8000 Munich 5

Patent attorneys Menges & Prahl, Erhardtstr. 12, D-8000 Munich 5 Graduate engineer Rolf Menges

Dipl.-Chem. Dr. Horst Prahl

Telephone (089) 26 3847 Telex 529581 BIPATd Telegram BIPAT Munich

YourSign / Yourref.

OurSign / Ourref. S.

Date 05/18/1983

Simon Engineering Dudley Limited Dudley, West Midlands, England

Lifting platform

The invention relates to a work or lifting platform, usually, but not exclusively, on located in a vehicle and used to move equipment or personnel to elevated positions above the To bring to the ground. Devices of this type usually have a swivel base on which an articulated boom system is attached, which consists of two or more than two arms, the end to end rotatable with each other are connected, and from hydraulic actuating cylinders, by means of which the boom around horizontal axes are pivotable relative to each other and to the swivel base.

Regulations governing the manufacture and use of such equipment require that facilities be provided are that prevent the boom can be maneuvered in positions in which the stability of the vehicle is impaired to a dangerous extent, so that the vehicle can tip over in extreme cases. To that too many systems have already been proposed.

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the, for example, complicated systems of attacks, which, when the booms approach a potentially unstable condition, cause control valves to be actuated, to prevent further movement. Such systems are not secure enough, are expensive to maintain and can- ■■ -.- ■■ - ' cause damage when the equipment is in use.

In another system, a compensator mechanism is provided, which causes the second boom to be automatically raised relative to the first boom when the first boom is raised, allowing the booms to fully extend vertically but preventing them can be extended completely horizontally. In this way the center of gravity of the boom system stays within the limits of the device carrying it, which in the case of one; Appropriate to a group of the vehicle Ground-contacting supports that extend downward from the vehicle platform and come into contact with the ground are.

The object of the invention is to create a lifting platform with a compensator mechanism to increase the stability natural way to maintain, while the construction of the boom the operator has easy access to the lift granted and the use of lighter and thus less expensive components allowed as well as the Reduced the length of the boom in the transport or retracted state.

Accordingly, the invention provides a lifting platform with a swivel base on which an articulated boom system is attached, which consists of two or more than two cantilevers that are rotatably connected to one another end to end, and with hydraulic actuating cylinders for swiveling the extension

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casual about horizontal axes relative to each other and to the Swivel base, which is characterized in that a first or lowermost boom consists of a parallel granular linkage consists / wherein one end is rotatably connected to the swivel base, while the other end is a support device, the one maintains a constant position regardless of the elevation angle of the lowest boom, and that a second boom is rotatably connected to the support device, wherein a hydraulic actuating cylinder for the second boom is connected between these and the support device.

An embodiment of the invention is described in more detail below with reference to the drawing.

The single figure of the drawing shows schematically a lifting platform according to the invention.

In the exemplary embodiment described here, the lifting platform is via a swivel base 10 on the deck or chassis 11 attached to a vehicle designated as a whole by 12. The vehicle has two supports 13 for support on the ground, which are lowered when the lift is to be raised.

The lifting platform has a first boom, which is designated as a whole by 14, and consists of two elongated, parallel ones Parts 15 and 16 are made at mutually spaced locations on an upper part 17 of the swivel base 10 are rotatably articulated and at their free ends carry a support bracket 18 or bearing plate (bracket) on which the parts 15 and 16 are also rotatable are hinged. Semit form part 17, parts 15 and and the support bracket 18 a parallelograin linkage. A hydraulic one Actuating cylinder 19, which extends between the part 17 and the boom 14, can be extended, in order to thereby move the boom 14 relative to the swivel base 10

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to raise.

A second support bracket 20, which is fixed with respect to the support bracket 18, supports one end of a second or upper one Boom 21 which is pivoted to the support bracket 20 rotatably. A hydraulic actuator cylinder 22 extends between the boom 21 and the support device consisting of the support brackets 18 and 20 and is extendable to the to raise the second boom relative to the support bracket 20.

At the free end of the boom 21, a work basket or a work platform 23 is rotatably attached. One device (not shown) is provided to keep the basket 23 horizontal in all positions of the boom assembly keep.

In the equipment shown, the lower boom 14 is horizontal and the upper boom 21 with its free one The end is inclined downwards so that the basket 23 is in a position in which it is easily accessible to the operator is, i.e. it is in a transport position. The boom system can be moved from the transport position to various raised positions, some of which are shown as examples.

From the transport position, the lower boom 14 can be moved into position A when the cylinder 19 is extended the support brackets 18 and 20 maintain a constant position in space, thanks to the parallelogram structure of the boom 14. The upper boom 21 thus occupies position B. When the lower boom 14 is fully raised, the upper boom 21 can be raised further by extending the actuating cylinder 22 with the upper boom moving through position C to its fully raised position D.

In another maneuver, the cylinder 19 can remain closed while the cylinder 22 is extended to the Raise boom 21 to position E. The subsequent extension of the cylinder 19 therefore causes the boom 14 is raised to position A, whereupon the boom

21 will occupy position D.

Should both cylinders 19 and 22 be out of the transport position at the same time are extended, the basket 23 can be raised substantially in a straight line vertically.

If precautions are taken so that cylinder 22 is not completely closed in the transport position, then, even if the boom 14 is raised from its transport position, the basket 23 in its lowest Remain in position by closing the cylinder 22 further.

Since the cylinder 22 is arranged between the upper boom 21 and the support device 18, 20 of the parallelogram linkage is, the geometry of the system is such that the cylinder

22 is held under pressure and a substantially constant hydraulic pressure is required to the raise the second boom. This feature enables a lighter structure to be used for the actuating cylinders than is normally required for equipment of this type. Usually the actuating cylinder is for the upper one Arm of a pair of arms is arranged between the two arms, and in such an arrangement it is not possible to achieve a substantially constant hydraulic pressure.

The arrangement of the upper boom 21 alongside the lower boom 14 allows the basket 23 to move down into its

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To move position in which it is for the operator is easily accessible, whereby the overall length of the device in the transport position is also minimized.

A system of the type described in which the lifting of the second boom is automatic to compensate for the lifting of the lower boom, enables the booms to assume an almost vertical arrangement at maximum height, without the fear that an excessive overturning moment is generated in the state in which the booms are full are stretched out horizontally on one side or the other of the swivel base. The straight configuration at full Height allows the maximum height to be achieved with the minimum length of the boom, thereby increasing the overall length of the device in the transport position in which the Tragvorrichrung 18, 20 is arranged above the driver's cab of the vehicle is, is minimized *

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Claims (7)

Patent claims: 1. Lift with a swivel base on which an articulated boom system is attached, which consists of two or more than two booms consists, which are rotatably connected together end to end, and hydraulic actuating cylinders for pivoting the booms about horizontal axes relative to each other and to the swivel base, thereby characterized in that a first or lowermost boom (14) consists of a parallelogram linkage (15, 16, 17, 18), one end being pivoted to the swivel base (10) and the other end being a support device (18, 20) which maintains a constant position regardless of the elevation angle of the lowest boom (14), and that a second boom (21) is rotatably articulated on the support device (18, 20), a hydraulic Actuating cylinder (22) for the second boom and arranged between the latter and the support device connected to these. 2. Lifting platform according to claim 1, characterized in that the booms (14, 21) are connected to one another so that, when the lowermost boom (14) is overall horizontal, the second boom (21) is inclined downward from this can be so that the outermost end of the boom system (14, 21) at a lower height than the support device (18, 20) is. 3. Lifting platform according to claim 1 or 2, characterized by a work basket or a work platform (23) which is attached to the extreme end of the boom system (14, 21) is hinged, and by a device that the basket or keeps the platform (23) horizontal in all configurations of the boom system. 4. Lifting platform according to one of claims 1 to 3, characterized in that that the hydraulic actuating cylinder (22) is kept under pressure for the second boom (21) and that a substantially constant hydraulic pressure is required to lift the second boom. 5. Lifting platform according to one of claims 1 to 4, characterized in that that the second boom (21) is arranged next to the lower boom (14) so that the outermost end the second boom can be moved down to a height at which it is lower than the support device (18, 20) is. 6. Lifting platform according to one of claims 1 to 5, characterized in that that the support device (18, 20) has a first support bracket or bearing plate (18) with which the The parallelogram linkage of the lowest boom (14) is connected at mutually spaced points, and a second support bracket or bearing plate (20) rigidly attached to the first support bracket or bearing plate and on which the second or uppermost boom (21) is is hinged, the hydraulic actuating cylinder (22) for the second boom between this and the second support bracket or bearing plate is arranged and connected to these. 7. Lifting platform according to one of claims 1 to 6, characterized in that that the swivel base (10) on the deck or chassis (11) of a vehicle (12) in the vicinity of the rear thereof End is attached so that the boom system (14, 21) can be collapsed into a transport position in which the support device (18, 20) is arranged above the driver's cab.