EP3450389A1 - Method for increasing the working envelope in lifting platforms - Google Patents

Abstract

Method for increasing the working range of aerial work platforms (1), in particular mobile aerial work platforms, wherein the aerial work platform (1) has a kinematics structure with a plurality of independently movable kinematic elements, wherein the kinematic elements are movable into different mounting positions and for the Aufstellposition each a work area is determined and a kinematics movements of the kinematic elements are permitted by a safety control as a function of the respective working area, at least one kinematic element being locked in its current kinematic position or the speed of at least one kinematic element being limited to a predetermined maximum speed value starting from its current kinematics position and then is automatically switched from the safety control to a work area, which the dynamic load d it does not take into account, or only to a lesser extent, at least one locked or limited in its maximum speed kinematic element.

Description

The invention relates to a method for increasing the working range in aerial work platforms, in particular mobile aerial work platforms, the aerial work platform having a kinematics structure with a plurality of independently movable kinematic elements, wherein the kinematic elements are movable into different mounting positions and for the respective installation positions each a work area is determined and a safety control in response to the respective work area only for the respective working area permissible kinematics movements of the kinematic elements are released.

For aerial work platforms, in particular for mobile aerial work platforms, a suitable safety control must be used to ensure that the stability and strength limits are not exceeded during the operation of the aerial work platform. The amount of all allowed aerial work platform positions is called a workspace. Various methods can be used to determine the work area and to monitor it. The normatively required boundary conditions are mathematically transformed into permitted and forbidden movements.

The current working area of an aerial work platform is dependent on its installation configuration, in particular the position of the support device. This setup configuration identifies the components that remain unchanged during an aerial work platform deployment. There are aerial work platforms which provide a reduced working area during the erection process. In this case, the release of a work area on the position of one or more kinematic elements of the aerial work platform, wherein the departure of this position is prevented.

When determining the working area, according to the standard, the dead weight, payload, wind power and a dynamic load must be taken into account. The dynamic load takes into account all loads on the moving parts of an aerial work platform.

In known aerial work platforms, each aerial work platform has one or more work areas which are assigned to a specific set-up configuration. In this case, the switching between the work areas in dependence on the position of the lifting device or manually. For aerial work platforms that do not permit one or more directions of movement in certain areas, the working area is adjusted in advance and can not be controlled during an aerial work platform use. The workspaces of known aerial work platforms are thus limited.

Out DE 38 07 966 A1 and DE 10 2012 106 222 A1 are known aerial work platforms with several kinematic elements. From DIN EN 280, April 2016, Mobile aerial work platforms - Calculation - Stability - Construction - Safety - Tests; Pages 18 - 24 identify the stability requirements for aerial work platforms.

The object of the invention is to increase the working range of aerial work platforms, without affecting the stability.

This object is achieved according to the invention by at least one kinematic element being locked in its current kinematic position or limiting the speed of at least one kinematic element from its current kinematics position to a predetermined maximum speed value and then automatically switched to a workspace by the safety control is, which takes into account the dynamic load of the at least one locked or limited in its maximum speed kinematic element not or only to a reduced extent.

To increase the working range thus one (or possibly more) kinematic element is locked in its current position electrically, hydraulically or mechanically or in another way or it is the speed of at least one kinematic element limited to a predetermined maximum speed value (eg very slow crawl speed) and then switched to a workspace that does not or only to a lesser extent takes into account the dynamic loading of the at least one locked or limited in its maximum speed kinematic element. At standstill and locking of a kinematic element, depending on the position of this kinematic element, its dynamic load can not even be taken into account or only to a lesser extent if dynamic transmission effects of the still moving kinematic elements can arise on the locked kinematic element. By limiting the maximum speed of a kinematic element, on the other hand, the dynamic load of the kinematic element is usually not neglected, but taken into account to a lesser extent. The position of the respective relevant kinematic element is completely arbitrary. By disregarding or discounting the dynamic load of this kinematic element, the workspace is automatically re-determined based on the current position of the particular kinematic element concerned, either by appropriate calculation or by selecting from factory stored data for all possible positions of the kinematic elements of the aerial work platform. By this locking or speed limit of at least one kinematic element is thus another, namely enlarged work area available. The freed-up reserve can be used as additional reach of the aerial work platform.

In a first preferred embodiment it is provided that the at least one kinematic element is manually locked by the operator or the speed of the at least one kinematic element is manually limited by the operator to the maximum speed value. The operator can thus decide for himself in any position of the kinematic elements that he wants to leave a certain kinematic element in the current position or move it at a low speed for a certain time. This kinematic element is electrically, hydraulically or mechanically locked or limited in its speed by the intervention of the operator, and subsequently an (enlarged) working range is determined and released.

Alternatively, it can also be provided that the position of at least one kinematic element of a sensor connected to the safety control is monitored and is detected upon detection of a standstill of the at least one kinematic element over a predetermined period of time, this at least one kinematic element of the safety control automatically in its current kinematic position. Thus, if at least one kinematic element is not actuated by the operator of the aerial work platform for a predetermined period of time, this is detected by a sensor and forwarded to the safety controller, which then automatically locks the respective kinematic element in the current position and releases a larger working area.

It can also be provided that the speed of at least one kinematic element is monitored by a sensor connected to the safety control and upon detection of a falling below the maximum speed value of the at least one kinematic element over a predetermined period, the speed of this at least one kinematic element of the safety control automatically to the maximum Speed value is limited. This automatically releases a larger workspace from the safety controller as well.

In a preferred embodiment it is provided that the position of all kinematic elements is monitored. All kinematic elements which are stationary in the given period of time are then automatically locked and all kinematic elements moving at a correspondingly low speed in the given period of time are correspondingly limited in their maximum speed, so that an even larger working range is available for the remaining kinematic elements.

Furthermore, it is preferably provided that predetermined kinematics situations with at least one locked or limited in its speed to the maximum speed value kinematic element as different driving modes in a memory of the safety controller and the operator of the respective desired driving mode is selectable, which automatically by the safety control on the associated Workspaces is switched. By a selection of such driving modes, the operation can be simplified because the operator does not actively himself at least one kinematic element lock by manual intervention or limit its speed, but can select from a manageable number of predetermined driving modes.

Fig. 1

eine Hubarbeitsbühne,

Fig. 2

die bei der Hubarbeitsbühne auftretenden dynamischen Kräfte bei freier Rotation um einen Drehpunkt A,

Fig. 3

das durch die dynamischen Kräfte nach Fig. 2 erzeugte Kippmoment,

Fig. 4

die durch eine Rotation nur um einen Drehpunkt B erzeugten Kräfte und in

Fig. 5

das durch die dynamischen Kräfte nach Fig. 4 erzeugte Kippmoment.

The invention is explained in more detail below by way of example with reference to the drawing. This shows in each case in a schematic representation in

Fig. 1

an aerial work platform,

Fig. 2

the dynamic forces occurring at the working platform with free rotation about a pivot point A,

Fig. 3

that by the dynamic forces Fig. 2 generated tilting moment,

Fig. 4

the forces generated by a rotation only about a pivot point B and in

Fig. 5

that by the dynamic forces Fig. 4 generated tilting moment.

A highly simplified, preferably self-propelled aerial work platform 1 comprises a chassis 2 which is free-standing by a support means 3 (for example a plurality of telescopic supports), i. not standing on the wheels, not shown, is placed on an inclined bottom surface 4.

The aerial work platform 1 has a kinematics structure with a plurality of independently movable kinematics elements, namely a lower, preferably telescopic lifting device 5, which is pivotable in a first pivot point A about a horizontal axis. In addition, usually the lower lifting device 5 is also pivotable about a vertical axis relative to the chassis 2, which is not shown in the figures. The lower lifting device 5 passes through a further pivot point B in an upper, preferably telescopic lifting device 6, at the free end of a work basket 7 is arranged.

As can be seen, the kinematics structure of the aerial work platform 1 has a multiplicity of Degrees of freedom. Thus, the lower lifting device 5 can be changed by their telescopic length. In addition, it can be pivoted about a vertical axis relative to the chassis 2 and about the pivot point A about a horizontal axis. The upper lifting device 6 can be changed in length due to their telescopability. Furthermore, it can be pivoted about the pivot point B about a horizontal axis relative to the lower lifting device 5.

Other degrees of freedom are possible, but not shown in the figures for clarity. Thus, for example, the work basket 7 about a horizontal axis relative to the upper lifting device 6 can be pivoted.

In the Fig. 2 and 3 a situation of the kinematic structure is shown, in which the rotation about the pivot points A and B is allowed, ie the corresponding movements are not locked. In this case, the in Fig. 2 shown dynamic forces F1a in the center of gravity of the lower lifting device 5, F2a in the center of gravity of the upper lifting device 6 and F3a in the center of gravity of the working basket 7. This results in the Fig. 3 shown individual tilting moments in conjunction with the respective lever arms L1a, L2a, L3a.

The total tilting moment M_Kipp_a then results as follows: $$\mathrm{M\_Kipp\_a}=\mathrm{F}\mathrm{1}\mathrm{a}\times \mathrm{L}\mathrm{1}\mathrm{a}+\mathrm{F}\mathrm{2}\mathrm{a}\times \mathrm{L}\mathrm{2}\mathrm{a}+\mathrm{F}\mathrm{3}\mathrm{a}\times \mathrm{L}\mathrm{3}\mathrm{a}\mathrm{,}$$

Is now the operator of the aerial work platform 1 (or automatically), the lower lifting device 5, for example, in the in Fig. 4 Locked position shown, so that no rotation around the pivot point A is possible, only the in Fig. 4 shown dynamic forces by a rotation about the pivot point B, namely F2b and F3b. In contrast, the dynamic force F1b is 0.

$$\mathrm{F}\mathrm{2}\mathrm{a}=\mathrm{F}\mathrm{2}\mathrm{b}$$

$$\mathrm{F}\mathrm{3}\mathrm{a}=\mathrm{F}\mathrm{3}\mathrm{b}$$

$$\mathrm{L}\mathrm{2}\mathrm{a}>\mathrm{L}\mathrm{2}\mathrm{b}$$

$$\mathrm{L}\mathrm{3}\mathrm{a}>\mathrm{L}\mathrm{3}\mathrm{b}\mathrm{.}$$

From these dynamic forces results in a tilting moment corresponding to the lever arms L2b and L3b, as in Fig. 5 is shown. The total tilting moment M_Kipp_b is given by $$\begin{array}{cc}\hfill \mathrm{M\_Kipp\_b}& =\mathrm{F}\mathrm{1}\mathrm{b}\times \mathrm{L}\mathrm{1}\mathrm{b}+\mathrm{F}\mathrm{2}\mathrm{b}\times \mathrm{L}\mathrm{2}\mathrm{b}+\mathrm{F}\mathrm{3}\mathrm{b}\times \mathrm{L}\mathrm{3}\mathrm{b}\hfill \\ \hfill & =\mathrm{F}\mathrm{2}\mathrm{b}\times \mathrm{L}\mathrm{2}\mathrm{b}+\mathrm{F}\mathrm{3}\mathrm{b}\times \mathrm{L}\mathrm{3}\mathrm{b}\hfill \\ \hfill & <\mathrm{M\_Kipp\_a}.\mathrm{because}\hfill \\ \hfill \mathrm{F}\mathrm{1}\mathrm{a}>\mathrm{F}\mathrm{1}\mathrm{b}& \left(\mathrm{F}\mathrm{1}\mathrm{b}=\mathrm{0}\right)\hfill \end{array}$$

$$\mathrm{F}\mathrm{2}\mathrm{a}=\mathrm{F}\mathrm{2}\mathrm{b}$$

$$\mathrm{F}\mathrm{3}\mathrm{a}=\mathrm{F}\mathrm{3}\mathrm{b}$$

$$\mathrm{L}\mathrm{2}\mathrm{a}>\mathrm{L}\mathrm{2}\mathrm{b}$$

$$\mathrm{L}\mathrm{3}\mathrm{a}>\mathrm{L}\mathrm{3}\mathrm{b}\mathrm{,}$$

With a locking of the rotation about the pivot point A, the tilting moment M_Kipp_b occurring due to the dynamic forces is thus smaller than the maximum tilting moment M_Kipp_a when the pivot point A is not locked, so that a larger working range is available if a rotation about the pivot point A is available is locked, which on the one hand can be done by the fact that the operator causes a mechanical, electrical or hydraulic locking of the rotary joint A or the safety control of the working platform 1 performs a lock automatically, eg if it is determined by a sensor that the lower lifting device 5 has not been pivoted about the pivot point A for a predetermined period of time.

In addition to a complete locking of a kinematic element of the kinematic structure, the working range can also be increased by limiting the speed of a selected kinematic element to a maximum speed value (eg, crawl speed). Even such a lower speed of movement opens up the possibility of correspondingly lower consideration of the dynamic loading of the relevant kinematic element in determining the current working area and thereby increasing the working area.

LIST OF REFERENCE NUMBERS

1

platform

2

chassis

3

support means

4

inclined floor surface

5

lower lifting device

6

upper lifting device

7

work basket

A

pivot point

B

pivot point

Claims (6)

Method for increasing the working range of aerial work platforms (1), in particular mobile aerial work platforms, wherein the aerial work platform (1) has a kinematics structure with a plurality of independently movable kinematic elements, wherein the kinematic elements are movable into different mounting positions and for the Aufstellposition each a work area is determined and released by a safety controller in dependence on the respective work area only for the respective work area permissible kinematics movements of the kinematic elements,
characterized,
that at least one kinematic element is locked in its current kinematic position or the speed of at least one kinematic element is limited to a predetermined maximum speed value starting from its current kinematic position and then automatically switched by the safety control to a work area which controls the dynamic load of the at least one locked or in his maximum speed limited kinematic element is not or only to a lesser extent taken into account. Method according to claim 1,
characterized,
that the at least one kinematic element is manually locked by the operator or the speed of the at least one kinematic element is manually limited by the operator to the maximum speed value. Method according to claim 1 or 2,
characterized,
in that the position of at least one kinematic element is monitored by a sensor connected to the safety control, and when a at least one kinematic element is detected for a predetermined period of time, this at least one kinematic element is automatically locked by the safety control in its current kinematics position. Method according to claim 1 or 2,
characterized,
in that the speed of at least one kinematic element is monitored by a sensor connected to the safety control and the speed of this at least one kinematic element is automatically limited to the maximum speed value by the safety control when the maximum speed value of the at least one kinematic element is undershot over a predetermined period of time. Method according to claim 3 or 4,
characterized,
that the position of all kinematic elements is monitored. Method according to claim 1,
characterized,
that predetermined kinematics situations with at least one locked or limited in its speed to the maximum speed value kinematics as different driving modes in a memory of the safety controller and the operator of the respective desired driving mode is selectable, which is automatically switched by the safety controller to the associated work areas.

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