AU694128B2

AU694128B2 - Self-levelling platform assembly

Info

Publication number: AU694128B2
Application number: AU72988/94A
Authority: AU
Inventors: Adrian Van Der Kamp
Original assignee: BARKLY WELDERS Pty Ltd
Current assignee: BARKLY WELDERS Pty Ltd
Priority date: 1994-09-14
Filing date: 1994-09-14
Publication date: 1998-07-16
Anticipated expiration: 2014-09-14
Also published as: AU7298894A

Description

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AUSTRALIA

PATENTS ACT 1990 n' n M D T. WR T P P r C' T T A T T O N S P E C I F C A T 1 0 FOR A STANDARD PATENT

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ORIGINAL

Name of Applicant: Actual Inventor: Address for Service: BARKLY WELDERS PTY LTD, A.C.N. 010 358 531 Adrian VAN DER KAMP SHELSTON WATERS 55 Clarence Street SYDNEY NSW 2000 r aaoa r o~o~ll o Invention Title: "SELF-LEVELLING PLATFORM ASSEMBLY" 4)J The following statement is a full description of this invention, including the best method of performing it known to us:- 1 2 The present invention relates to elevated work platforms of the type adapted to be mounted on booms.

It is well known to mount a platform on the end of a crane boom to facilitate positioning of the platform at a remote and usually an elevated position. It will be appreciated that as the crane boom changes its angle of inclination, the platform itself must be angularly displaced relative to the boom in order to maintain a level orientation. This requirement gives rise to the 10 necessity of having some form of levelling means *connecting the platform to the boom.

Traditionally, an hydraulic actuator has been mounted between the platform and boom arm, with the hydraulics being manually controlled by the operator in

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15 order to vary the angle of inclination of the platform relative to the boom. With such arrangements, the operator, who is usually located either on the platform or at ground level, is required to manipulate controls to maintain the platform in a level orientation. This task tends to slow down the correct positioning of the boom and in certain situations, such as fire fighting applications, this time factor may be critical.

Moreover, not only does the manually controlled levelling procedure slow down the deployment of the platform, it may also reduce the accuracy of the deployment and result in the platform not being precisely level. This also has adverse effects in terms of safety, particularly where the platform is manned.

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.3- In an attempt to ameliorate these problems, parallelogram type linkage arrangements have been configured to effect self-levelling of a platform connected to a boom of fixed length However, such linkages are unsuitable for use with telescoping booms as the variable length of the boom cannot be accommodated by the predetermined action of these linkages. Moreover, such linkages cannot accommodate variations in platform inclination resulting from external factors such as booms support being mounted on sloping grounds, or deflecting under load.

0 00 It is an object of the invention to overcome or ameliorate at least some of these 000000deficiencies of the prior art.

Accordingly, the invention provides a self-levelling platform assembly adapted for mounting to the remote end of a boom supported for rotation about a first generally #0 0 horizontal axis, said assembly comprising: a platform mounted to a chassis for rotation about a second axis generally parallel to and spaced apart from said first axis, said chassis being adapted to be mounted to the boom; drive means disposed intermediate the platform and the chassis to effect rotation of the platform relative to the chassis about said second axis; level sensing means to provide a control signal indicative of the angle of inclination of the platform; and control means to control the drive means in response to said control signal such that the platform tends to be maintained at a predetermined angle of inclination throughout a range o f rotational movement of the boom about the first axis.

t7t E0ON £69900 *SN31bMf NOIS-13HS 90:83T -4- Preferably, the drive means includes an hydraulic actuator although other forms of actuators although other forms of actuators may be equally applicable. The hydraulic actuator may be driven by an hydraulic accumulator which is in turn charged by an electrically driven hydraulic pumnp. Alternatively or additionally, the hydraulic actuator may be driven by an hydraulic accumulator which is in turn charged by an electrically driven hydraulic pump. In either case, the hydraulic pump is conveniently driven by batteries thus making the assembly operatable independently of an exterinal power supply.

Unless the context clearly requires otherwise, throughout the description and the claims, the words 'comprise', 'comprising', and the like are to be construed in an inclusive as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:-- Fsligure I is perspective view of a self-levelling platform assembly according to the invention; Figure 2 is a reverse angle perspective view of the platform of Figure 1;

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Figure 3 is a detailed perspective view of the connection between the self-levelling platform assembly and the boom; Figure 4 shows a pair of reverse angle perspective views of the connection component which, in use, is fixed to the boom; Figure 5 is a perspective view of the chassis of the self-levelling platform assembly; Figure 6 is a perspective view of the hydraulic oo 10 actuator and counterbalance valve; 0...Figure 7 is a pair of reverse angle perspective views showing the platform's self-levelling base and support for the slewing bearing; Figure 8 is a perspective view of the platform support spider; Figure 9 shows the platform support spider of Figure 8 as viewed from below; Figure 10 is perspective view of the first layer of hydraulic components contained within the hydraulic pannier; Figure 11 is a perspective view of layer two (folded out) and layer three of the hydraulics within the hydraulic pannier; and Figure 12 is a perspective view of the electrical pannier.

Referring to Figure 1, the invention provides a self-levelling platform assembly 1 adapted to be mounted by connection component 2 to the remote end of a crane -6boom (not shown). The crane boom is mounted at the other end for rotation about a first generally horizontal axis. Connection component 2 is connected to chassis 3 by hook member 4 (best illustrated in Figure In use, nook member 4 is hooked to connection component 2 and is securely fixed by means of a retaining pin (not shown).

Chassis 3 includes ground engaging feet 5, 6 and 7, platform mounting bracket 8 and drive mounting bracket 9 (best illustrated in Figure 10 Referring to Figure 2, platform 10 includes platform floor 11, walls 12 and control panel 13.

Platform floor 11 is supported on spider arm assembly 14 which, referring to Figures 9 and 7, is in turn supported on self-levelling base 15. The mating faces of spider arm assembly 14 and self-levelling base 15 allow limited rotation of one with respect to the other about a substantially vertical axis. This rotation is herein referred to as slewing.

Referring now to Figures 5 and 7, self-levelling base 15 is adapted to be mounted to platform mounting bracket 8 at bush 16 via a pin (not shown) and to piston 17 of drive means 18 (refer to Figure 6) at bracket 19 via another pin (also not shown).

As illustrated in Figure 6, drive means 18 comprises an hydraulic piston/cylinder unit supplied with hydraulic fluid via counter-balance valve Counter-balance valve 20 locks the piston in the cylinder and requires hydraulic pressure in order to unlock. This 7 prevents piston movement in the case of electrical or hydraulic failure.

Referring to Figure 2, panniers 21 and 22 are provided to house level sensing means 23, control means 24 and the various anrcillary electrical and hydraulic components necessary to actuate drive means 18 (refer to Figures 10, 11 and 12).

When the platform is non-level, level sensing means 23 sends a signal to control means 24 via electrical relays 36, which activates drive means 18 in the appropriate direction to return the platform to a level orientation. In the case of raising or lowering of the boom, the control circuitry cycles many times per second to provide an effective continuous system response, thereby avoiding sudden and potentially destabilising changes in platform orientation. Hydraulic oil for this function is supplied from the charged accumulator 26, and additionally from the hydraulic pump 28 if the accumulator pressure is low.

Accumulator 26 is fitted with a high and low pressure sensor 30 which switches pump 28 on when the pressure drops below a pre-set level, and off when the accumulator is sufficiently charged. Accumulator 26 functions to provide an hydraulic pressure reserve in the event of pump failure, and to insulate the hydraulic pump from continual on/off switching as the level sensor fluctuates during ascent or descent. During peak flow, the combined flow of the pump and accumulator may be i i i~ 8 required to meet system demands.

The counter balance valve 38 functions as a safety device which locks the drive means 18 in the case of electrical or hydraulic failure. Thus, a minimum hydraulic pressure is required to unlock the valve. As a further safety feature, as shown in Figure 12, there is provided an emergency siren 32, which is activated from the control panel 13.

As discussed previously, all electrical power for the self-levelling platform assembly is provided by o batteries 34 located in the electrical pE.nnier 21.

t 00:. Electrical relays 36 are also located within electrical pannier 21 to convert the low power signal, from level sensing means 23, to a signal capable of activating the 15 control means 24.

The slewing of spider arm assembly 14 with respect to self-levelling base 15 is also hydraulically driven.

4 In particular, the pinion of a hydraulic motor engages a ring gear to facilitate slewing.

20 With conventional platforms power must be supplied along the considerable distance of the boom arm.

Moreover, these prior art platforms can only be used in 2 conjunction with a crane which is specifically adapted for the purpose by having power supply lines extending along the length of the boom. Such cranes are often referred to as dedicated cranes. In contrast, the present invention overcomes the impracticality of providing electrical or hydraulic power to the distal end 9 of a crane and is capable of simple, quick and completely safe connection and disconnection from a crane. This is achieved by modifying the distal end of the crane to carry the appropriate connection component such that the levelling platform can be connected and used throughout the full elevation and declination range of the crane, whilst not compromising the usual lift functions.

Moreover, unlike parallelogram links, the present invention is not adversely affected by the variable length of a telescoping crane boom. As such, the Sinvention is particularly useful in its ability to rapidly convert a conventional non-dedicated crane from o e 9 o its usual crane duty to include the additional capability of providing a working platform.

15 The embodiment described has been provided with a slewing capability. Whilst not essential, this slewing function allows the crane to stand off from a wall or the like at an oblique angle, while allowing the platform itself to fit squarely against the wall. A simpler and cheaper unit is also contemplated, featuring a smaller, rounded platform without the slewing capability.

Prior art work platforms require a dedicated vehicle in addition to the boom and platform assemblies.

The units are therefore very expensive and are often under utilised. The invention eliminates the requirement for a dedicated vehicle and provides versatility to an existing hydraulic crane. This second capability increases the utilisation of the crane, providing 10 improved operating economics.

To contain manufacturing costs, dedicated elevating work platforms tend to be spidery and typically feature a disconcerting swaying motion at extreme extension. In contrast, using a crane as the lifting mechanism provides a very solid and stable support for the self-levelling Work platform, a significantly stiffer, more secure and hence safer base from which to work.

Moreover, hydraulic telescoping cranes provide the capability to lift the self-levelling work platform to 2greater heights well beyond reach of the vast majority of dedicated elevating work platforms. For example, full extension heights of 50 meters or more are commonly found in cranes, but are extremely rare in dedicated elevating platforms. Thus, the invention represents a commercially significant improvement over the prior art.

Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims

1. A self-levelling platform assembly adapted for mounting to the remote end of a boom supported for rotation about a first generally horizontal axis, said assenbly comprising: a platform mounted to a chassis for rotation about a second axis generally parallel to and spaced apart from said first axis, said chassis being adapted to be mounted to the b~oomn; drive means disposed intermediate the platform and the chassis to effect rotation of 00. the platform relative to the chassis about said second axis; t0 level sensing means to provide a control signal indicative of the angle of inclination of the platform; and 00 control means to control the drive means in response to said control signal such that the platform tends to be maintained at a predetermined angle of inclination throughout a range of rotational movement of the boom about the first axis.

2. A self-levelling platform assembly as claimed in claim 1, wherein the chassis,~& adapted to be releasably mounted to an intermediate connection component which is adapted to be fixed to the remote end of the boom,

3. A self-levelling platform as defined in chtim I or 2, wherein the hydraulic pump is powered by batteries located within the platform. 2o 4. A self-levelling platform assembly as defined in any preceding claim, wherein the platform includes slowing means. A self-levelling platform as claimed in any preceding claim, wherein the drive means includes an hydraulic actuator. 906 17SO 'ON 26929BE900 S831UM NOIS13HS S0~1 t7~0ON £S9~8~900 4- S~i~Jr'1 NOiSBHS BS/S0/~0 11 II L-

12- 6. A self-levelling -latform as defined in claim 5, wherein the hydraulic actuator is pressurised via an hydraulic accumulator, said accumulator being charged by an electrically driven hydraulic pump. 7. A self-levelling platform as defined in claim 5, wherein the hydraulic actuator is Spressurised directly from an electrically driven hydraulic pump. 8. A self-levelling platform assembly as defined in any one of the preceding claims, wherein said predetermined angle of inclination of the platform is substantially 0 0 0 1 o0 o C, horizontal. 9. A self-levelling platform assembly substantially as herein described with reference to the accompanying drawings. DATED this 2nd Day of June, 1998 BARKLY WELDERS PTY LTD Attorney: JOHN B. REDFERN Fellow Institute of Patent Attorneys of Australia of BALDWIN SHELSTON WATERS 26SSBE900 S 31UM N01S13HS 90:8T 86/90/E0 £9~98~S00 S~iBP1 NOiS13-IS 90:81 86/90/~0 ABSTRACT The invention relates to a self-levelling platform assembly adapted for mounting to the remote end of a boom about a first generally horizontal axis, the assembly comprising a platform (10) mounted to the boom for rotation about a second axis generally parallel to and spaced apart from the first axis, drive means (18) disposed to effect rotation of the platform relative to the boom about the second axis, level sensing means (23) to provide a control signal indicative of the angle of inclination of the platform relative to the horizontal, and control means (24) to control the drive means in response to the control signal such that the platform is substantially maintained at a predetermined angle of inclination throughout a range of rotational movements of the boom about the first axis.