WO2005032868A1

WO2005032868A1 - A method and a device for adjusting the position og a windowpane between two end positions

Info

Publication number: WO2005032868A1
Application number: PCT/SE2004/001416
Authority: WO
Inventors: Scherzad Isa; Deniz Cinkitas; Ulf Cedergren; Steven Eriksson; Anders Olsson
Original assignee: Scania Cv Ab (Publ)
Priority date: 2003-10-08
Filing date: 2004-10-04
Publication date: 2005-04-14
Also published as: SE526607C2; DE112004001844T5; SE0302656L; SE0302656D0

Abstract

The invention relates to a method and a device for adjusting the position of an object (2) which, by means of a driving arrangement (3), is movable between two end positions, which driving arrangement (3) is operated by means of a manually operable manoeuvring arrangement (12). Closure of first or second contact means (13a, 13b) forming part of the manoeuvring arrangement causes the object to move towards the respective first or second end position, and rotation in a first or second direction of rotation of a manoeuvring means (14) supported for rotation in the manoeuvring arrangement causes said object to move towards the respective first or second end position in a manner related to the rotary motion of the manoeuvring means. The invention also relates to a manoeuvring arrangement (12) suitable for use with the method according to the invention and the device according to the invention.

Description

Applicant: SCANIA CV AB

Method and device for adjusting the position of an object, and manoeuyring arrangement

FIELD OF THE INVENTION, AND STATE OF THE ART

The present invention relates to a method according to the preamble of claim 1 and a device according to the preamble of claim 4 for adjusting the position of an object which, by means of a driving arrangement, is movable between two end positions. The invention also relates to a manoeuvring arrangement according to the preamble of claim 8.

The method and the device according to the invention, as also the manoeuvring arrangement according to the invention, are particularly intended to be used for adjusting the position of a windowpane in a vehicle, e.g. in a truck or passenger car, which windowpane can by means of an electric motor be raised and lowered between upper and lower end positions. Conventional devices for adjusting the position of a windowpane in a vehicle usually comprise a manoeuvring arrangement in the form of a set of push-buttons or a toggle switch which, either directly or via a control unit, controls the energy supply to the motor which moves the windowpane, so that the motor rotates in a desired direction for upward or downward movement of the windowpane. By means of the manoeuvring arrangement, a person in the vehicle, which person is hereinafter called the user, can manoeuvre the vehicle window to a desired position. As, for example, described in US 5 598 918 A, another known practice is to have an adjusting device of the type here concerned which comprises two different modes of manoeuvring, whereby a first manoeuvring mode entails pressing a button which results in the windowpane moving all the way to a desired end position even if the user releases the push-button or toggle switch, and a second manoeuvring mode entailing pressing a button which results in the windowpane moving in a desired direction so long as the user holds the push-button or toggle switch in a certain position. The first type of manoeuvring mode is hereinafter called "automatic manoeuvring" and the second type of manoeuvring mode is hereinafter called "manual manoeuvring". Automatic manoeuvring uses a brief pressure on the pushbutton or toggle switch to move the windowpane to a fully open or fully closed position, whereas manual manoeuvring makes it possible to position the windowpane at a desired position between the two end positions. A disadvantage of the solution according to US 5 598 918 A, in which the same toggle switch is used for both manual manoeuvring and automatic manoeuvring, is that there is risk of the user unintentionally moving the toggle switch to a wrong position so that automatic manoeuvring takes place instead of intended manual manoeuvring, thereby, in a manner possibly dangerous in traffic, distracting a vehicle driver who handles the adjusting device concerned while the vehicle is in motion. Automatic manoeuvring also requires the user to release the toggle switch at precisely the right time if the windowpane is to come to a halt at a desired position. It may easily happen that the windowpane comes to a halt too soon or too late, thereby often requiring a number of repeat pressures to manoeuvre the windowpane to precisely the desired position.

OBJECT OF THE INVENTION

The object of the present invention is to provide a solution which enables reliable and user-friendly adjustment of the position of an object, e.g. a windowpane in a vehicle, which can, by means of a driving arrangement, be moved between two end positions.

SUMMARY OF THE INVENTION

According to the invention, said object is achieved by means of a method exhibiting the features indicated in claim 1 and a device exhibiting the features indicated in claim 4.

The solution according to the invention entails closure of a first contact means which forms part of the manoeuvring arrangement, resulting in the object, when stationary at a distance from a first of said end positions, being caused to move towards the first end position, and rotation in a first direction of rotation of a manoeuvring means supported for rotation in the manoeuvring arrangement, causing said object to move towards the first end position in a manner related to the rotary motion of the manoeuvring means, entails closure of a second contact means forming part of the manoeuvring arrangement, resulting in the object, when stationary at a distance from the second end position, being caused to move towards the second end position, and entails rotation of the manoeuvring means in a second direction of rotation, causing said object to move towards the second end position in a manner related to the rotary motion of the manoeuvring means. Contact means can therefore be used for the abovementioned type of automatic manoeuvring, i.e. for applying a single brief pressure to cause the object to move to a desired end position, while at the same time the manoeuvring means supported for rotation can be used for the abovementioned type of manual manoeuvring, i.e. for positioning the object at a desired position between the two end positions. The fact that automatic and manual manoeuvring are effected by different types of manoeuvring movements, pressure and rolling respectively, reduces the risk of the user unintentionally using a manoeuvring mode other than that intended at the time. The fact that rotation of the manoeuvring means causes the object to move in a manner related to the rotary motion of the manoeuvring means results in the object coming to a halt when the rotation of the manoeuvring means ceases, thereby making it very easy for the user to adjust the position of the object with good accuracy during manual manoeuvring.

According to an embodiment of the invention, when the object is moving towards one of the end positions after closure of the first or second contact means, rotation of the manoeuvring means in the first or second direction of rotation causes the object to move towards the first or second end position respectively in a manner related to the rotary motion of the manoeuvring means. It thus becomes easy to change over from automatic manoeuvring to manual manoeuvring during ongoing movement of the object.

Further embodiments of the method according to the invention and the device according to the invention are indicated by the dependent claims and the description set out below.

The invention also relates to a novel type of manoeuvring arrangement suitable for use with the method according to the invention and the device according to the invention. This manoeuvring arrangement exhibits the features indicated in claim 8. With the manoeuvring arrangement according to the invention, the manoeuvring means supported for rotation is accessible to the user in the region between the pressure surfaces of the toggle switch, thereby making it possible to design a space-saving manoeuvring arrangement with both toggle switch function and rolling function. The manoeuvring arrangement according to the invention also makes it possible for the user to change over quickly and easily between operating the toggle switch and operating the rotatable manoeuvring means.

According to an embodiment of the invention, the manoeuvring arrangement comprises a pulse emitter which has a spindle end, and said manoeuvring means is mounted on, for joint rotation with, said spindle end in such a way that the centreline of the spindle end constitutes the axis of rotation of the manoeuvring means. The result is a simple and appropriate way of fastening the manoeuvring means for rotation while at the same time enabling easy and effective detection of its rotary movements.

Further embodiments of the manoeuvring arrangement according to the invention are indicated by the dependent claims and the description set out below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described below in more detail by means of examples of embodiments with reference to the attached drawings, in which :

Fig. 1 depicts a schematic illustration of a device according to an embodiment of the present invention,

Fig. 2 depicts a schematic perspective view of a manoeuvring arrangement according to an embodiment of the present invention,

Fig. 3 depicts the manoeuvring arrangement according to Fig. 2 as seen in side view, Fig. 4 depicts the manoeuvring arrangement according to Fig. 2 as seen in plan view from above,

Figs. 5-7 depict flowcharts illustrating the method according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Fig. 1 illustrates a device 1 according to the present invention for adjusting the position of an object 2 which, by means of a driving arrangement 3, is movable between two end positions. In the embodiment illustrated, the device is designed for adjusting the position of an object in the form of a windowpane 2 (represented by a broken line in Fig. 1 ) of a vehicle, e.g. a windowpane arranged in a door 4 of a truck or a passenger car. The device according to the invention may also be designed for adjusting the position of other types of objects which, by means of a driving arrangement, are movable between two end positions. The windowpane 2 illustrated is movable between an upper first end position in which the window is fully closed and a lower second end position in which the window is fully or at least partly open.

The driving arrangement 3 comprises a reversible electric motor 5 and a mechanism 6 for converting rotary motion from the motor to linear motion of the windowpane 2. In the embodiment illustrated, said mechanism 6 comprises a ball screw 7 which is supported for rotation in the vehicle door 4 and connected to the motor's output shaft 5a via a gear 8. In this case the gear 8 comprises a first gearwheel 8a which is fastened to, for joint rotation with, the motor's output shaft 5a, and a second gearwheel 8b which is fastened to, for joint rotation with, the ball screw 7 and is in engagement with the first gearwheel 8a. Rotary motion in one direction or the other, depending on the direction of rotation of the motor's output shaft, is imparted to the ball screw 7 via the gear 8. A nut 9 with internal balls is arranged in engagement with the ball screw 7 so that the nut moves upwards or downwards along the ball screw when the ball screw is rotated in the respective direction. The windowpane 2 has its lower end 10 fastened to the nut 9 in order to accompany the nut as it moves along the ball screw. The windowpane 2 is thus movable relative to the ball screw 7 in the longitudinal direction of the ball screw, and rotation of the ball screw 7 will result in the windowpane moving between the first end position and the second end position in order to assume one of these end positions or a position between said end positions. Specialists will appreciate that the mechanism 6 may of course take many other forms than that here depicted.

The device 1 comprises a control unit 1 1 intended to be connected to, for control of, the driving arrangement 3, and a manually operable manoeuvring arrangement 12 connected to the control unit 1 1. With advantage, the manoeuvring arrangement 12 is fitted in the vehicle door 4 so as to be readily accessible to a driver or passenger in the vehicle, while the control unit 1 1 may be situated elsewhere in the vehicle. The control unit 1 1 comprises, for example, a processor arranged to receive signals from the manoeuvring arrangement 12 and convert them to control signals which cause the motor 5 to rotate in a desired direction and at a desired speed. The control unit 1 1 may also comprise relays and/or other electrical or electronic components connected between the processor and the motor 5 so that control signals originating from the processor effect the desired control of the motor 5. The control unit 1 1 is also arranged to receive signals from one or more sensors (not depicted) which indicate the position of the windowpane 2. Such a sensor may for example take the form of a pulse emitter arranged on the motor 5 and detecting the direction of rotation and speed of the motor's output shaft 5a.

The manoeuvring arrangement 12 comprises a first contact means 13 a, a second contact means 13b, a manoeuvring means 14 supported for rotation and a sensor 15 (see Figs. 2 and 4) for detecting rotary movement of the manoeuvring means. The sensor 15 is arranged to detect the direction of rotation and rotation speed of the manoeuvring means and advantageously takes the form of a pulse emitter. The contact means 13a, 13b and the sensor 15 are connected to the control unit 1 1 in order to respond to the user's manipulation of the manoeuvring arrangement 12 by giving input signals to the control unit 1 1 , which in its turn controls the motor 5 and hence the position of the windowpane on the basis of those input signals. The control unit 1 1 , the motor 5 and the manoeuvring arrangement 12 are suitably supplied with electric current from the vehicle's ordinary electricity supply system via undepicted conductors.

The control unit 1 1 is arranged to respond to closure of the first contact means 13a by causing the driving arrangement 3 to move the windowpane 2 towards a first of said end positions, e.g. the lower open position, if at the time of closure of the first contact means 13a the windowpane is stationary at a distance from the first end position. The control unit 1 1 is further arranged to respond to closure of the second contact means 13b by causing the driving arrangement 3 to move the windowpane 2 towards the second end position, e.g. the upper closed position, if at the time of closure of the second contact means 13b the windowpane 2 is stationary at a distance from the second end position. The control unit 1 1 is arranged to respond to said closure of the first or second contact means 13a, 13b by causing the driving arrangement 3 to move the windowpane 2 all the way to the first or second end position respectively if neither of the two contact means 13a, 13b closes and the manoeuvring means 14 is not rotated during the windowpane' s movement to the respective end position. This means that a single closure of the contact means 13a, 13b is sufficient for moving the windowpane 2 to a desired end position. The control unit 1 1 is preferably arranged to respond to renewed closure of the same contact means 13a, 13b or to closure of the second contact means 13b, 13a by causing the driving arrangement 3 to discontinue an ongoing movement of the windowpane 2 initiated by a previous closure of the firstnamed contact means. It is thus easy to bring the windowpane to a halt.

The control unit 1 1 is further arranged to respond to rotation of the manoeuvring means 14 in a first direction of rotation Rl , e.g. anticlockwise in Fig. 1 , by causing the driving arrangement 3 to move the windowpane 2 towards said first end position in a manner related to the rotary motion of the manoeuvring means if at the time when rotation of the manoeuvring means in the first direction of rotation is initiated the windowpane 2 is stationary at a distance from the first end position. The control unit 1 1 is also arranged to respond to rotation of the manoeuvring means 14 in a second direction of rotation R2 which is opposite to the first direction of rotation by causing the driving arrangement 3 to move the windowpane 2 towards the second end position in a manner related to the rotary motion of the manoeuvring means if at the time when rotation of the manoeuvring means in the second direction of rotation is initiated the windowpane 2 is stationary at a distance from the second end position.

The control unit 1 1 is further arranged to respond to rotation of the manoeuvring means 14 in the first or second direction of rotation at a time when the windowpane 2 is moving towards one of the end positions after closure of the first or second contact means 13a, 13b by causing the driving arrangement 3 to move the windowpane 2 towards the respective first or second end position in a manner related to the rotary motion of the manoeuvring means. In this case, the control of the windowpane's movement is thus taken over by the manoeuvring means 14, i.e. an ongoing automatic manoeuvre changes over to a manual manoeuvre.

The control unit 1 1 is with advantage arranged to respond to said rotation of the manoeuvring means 14 in the first or second direction of rotation by causing the driving arrangement 3 to move the windowpane 2 towards the respective end position at a speed which depends on the rotation speed of the manoeuvring means, preferably at a speed proportional to the rotation speed of the manoeuvring means.

Figs. 5-7 depict various flowcharts illustrating the method according to the present invention. In these flowcharts, "Y" stands for yes and "N" for no. The flowchart according to Fig. 5 starts from a situation in which the object 2 which is movable by means of the driving arrangement 3 is stationary at the abovementioned second end position, the flowchart according to Fig. 6 starts from a situation in which the object 2 is stationary at the abovementioned first end position, and the flowchart according to Fig. 7 starts from a situation in which the object 2 is stationary between the first and second end positions. For the sake of simplicity, Fig. 7 illustrates only the first step upon closure of either of the contact means 13a, 13b or upon rotation of the manoeuvring means 14 in either direction. The subsequent steps may be read in the boxes in Figs. 5 and 6 which denote the corresponding movement situations of the object. Figs. 2-4 illustrate a manoeuvring arrangement 12 which is particularly suitable for use with the method according to the invention and the device according to the invention. The manoeuvring arrangement 12 comprises a housing 20. A first contact means 13a and a second contact means 13b are arranged in the housing 20. The respective contact means 13a, 13b each take the form with advantage of a circuit-breaker, preferably a microgap circuit-breaker. The manoeuvring arrangement 12 further comprises a toggle switch 21 supported for pivoting in the housing 20 via two spindle ends 22a, 22b which protrude from the toggle switch 21 centrally to one another on their respective long sides 23a, 23b of the toggle switch. The toggle switch 21 is thus pivotable relative to the housing 20 about a pivot spindle 24 which coincides with the centrelines of said spindle ends 22a, 22b. The toggle switch 21 is provided with a first pressure surface 25a on a first side of the pivot spindle 24, and a second pressure surface 25b on the opposite second side of the pivot spindle 24. The toggle switch 21 is arranged to respond to pressure on the first pressure surface 25a by pivoting in a first direction Rl about the pivot spindle 24 so as to close the first contact means 13a, and to respond to pressure on the second pressure surface 25b by pivoting in a second direction R2 about the pivot spindle so as to close the second contact means 13b. In the embodiment illustrated, the respective contact means 13a, 13b are closed by the underside 26 of the toggle switch 21 depressing a contact element 27a, 27b of the respective contact means 13a, 13b when the toggle switch pivots towards the respective contact means 13a, 13b. The respective contact elements 27a, 27b are preloaded by a spring mechanism of the respective contact means 13a, 13b to cause them to assume a folded-up position. The toggle switch 21 is arranged, in an unloaded state, to assume a substantially horizontal neutral position and may for example be arranged so that after being pressed down it resumes this neutral position by the action of the contact element 27a, 27b pressed down by the toggle switch, i.e. by means of the return force exerted by the spring mechanism which returns the contact element 27a, 27b from a depressed to a folded-up position. The toggle switch 21 may of course also be provided with a return spring 28 of its own, as illustrated in Fig. 3, for returning the toggle switch 21 to the neutral position. The manoeuvring arrangement 12 is provided with a manoeuvring means 14 which is supported for rotation in the housing 20 and which extends through a recess 29 arranged in the toggle switch 21 between said pressure surfaces 25a, 25b so that the manoeuvring means 14 is accessible to a user from the top of the toggle switch with a view to rotation of said manoeuvring means. In the embodiment illustrated, an upper portion of the manoeuvring means 14 protrudes up through a hole 29 arranged centrally in the toggle switch between said pressure surfaces 25a, 25b. The manoeuvring means 14 has with advantage the shape of a wheel and can be rotated about a rotation spindle 30 which is substantially parallel with the pivot spindle 24 of the toggle switch. In the embodiment illustrated, the rotation spindle 30 of the manoeuvring means is arranged directly below the pivot spindle 24 of the toggle switch. The manoeuvring arrangement comprises a sensor 15 for detecting rotary movement of the manoeuvring means. The sensor 15 is adapted to detecting the direction of rotation and rotation speed of the manoeuvring means and takes with advantage the form of a pulse emitter.

In the embodiment illustrated, the manoeuvring arrangement 12 is provided with a sensor in the form of a pulse emitter comprising a spindle end 31 , and the manoeuvring means 14 is fitted to, for joint rotation with, said spindle end 31 in such a way that the centreline of the spindle end constitutes the axis of rotation 30 for the manoeuvring means. The pulse emitter 15 comprises in this case a body 32 in which the spindle end 31 is supported for rotation. From the body 32, the spindle end 31 extends through an aperture arranged in the housing 20 into the space inside the housing.

In the embodiment illustrated, the toggle switch 21 has a lowered portion 33 between the two pressure surfaces 25a, 25b. In this case the manoeuvring means 14 protrudes upwards in this lowered portion. The upper surface 34 of the manoeuvring means 14 is with advantage arranged substantially at the same height as the pressure surfaces 25a, 25b of the toggle switch, as viewed in the situation when the toggle switch 21 is in the neutral position, which is illustrated in Fig. 3.

The invention is of course in no way limited to the preferred embodiments described above, as a multiplicity of possibilities for modification thereof are likely to be obvious to a specialist in the field without thereby having to deviate from the basic concept of the invention as defined in the attached claims. For example, the device according to the invention may comprise a manoeuvring arrangement which takes a different form from that illustrated in Figs. 1-4.

Claims

1. A method for adjusting the position of an object (2) which, by means of a driving arrangement (3), is movable between two end positions, which driving arrangement (3) is operated by means of a manually operable manoeuvring arrangement (12), characterised - in that when the object (2) is stationary at a distance from a first of said end positions, closure of a first contact means (13a) which forms part of the manoeuvring arrangement (12) causes said object to move towards the first end position, and rotation in a first direction of rotation of a manoeuvring means (14) supported for rotation in the manoeuvring arrangement (12) causes said object to move towards the first end position in a manner related to the rotary motion of the manoeuvring means, - and that when the object (2) is stationary at a distance from the second end position, closure of a second contact means (13b) which forms part of the manoeuvring arrangement (12) causes said object to move towards the second end position, and rotation in a second direction of rotation of the manoeuvring means (14) causes said object to move towards the second end position in a manner related to the rotary motion of the manoeuvring means.

2. A method according to claim 1 , characterised in that when the object (2) is moving towards one of the end positions after closure of the first and second contact means (13a, 13b), rotation of the manoeuvring means (14) in the first or second direction of rotation causes said object to move towards the respective first or second end position in a manner related to the rotary motion of the manoeuvring means.

3. A method according to claim 1 or 2, characterised in that said rotation of the manoeuvring means (14) in the first or second direction of rotation causes the object to move towards the respective end position at a speed which depends on the rotation speed of the manoeuvring means, preferably at a speed proportional to the rotation speed of the manoeuvring means.

4. A device for adjusting the position of an object which, by means of a driving arrangement, is movable between two end positions, comprising a control unit (1 1) intended to be connected to, for control of, the driving arrangement, and a manually operable manoeuvring arrangement (12) connected to the control unit, characterised - in that the manoeuvring arrangement (12) comprises a first contact means (13a) and a second contact means (I3b), whereby the control unit (1 1) is arranged to respond to closure of the first contact means (13a) by causing the driving arrangement to move the object towards a first of said end positions if at the time when the first contact means closes the object is stationary at a distance from the first end position, and to respond to closure of the second contact means (13b) by causing the driving arrangement to move the object towards the second end position if at the time when the second contact means closes the object is stationary at a distance from the second end position, - and that the manoeuvring arrangement (12) further comprises a manoeuvring means (14) supported for rotation, whereby the control unit (1 1) is arranged to respond to rotation of the manoeuvring means (14) in a first direction of rotation by causing the driving arrangement to move the object towards the first end position in a manner related to the rotary motion of the manoeuvring means if at the time when the rotation of the manoeuvring means in the first direction of rotation is initiated the object is stationary at a distance from the first end position, and to respond to rotation of the manoeuvring means (14) in a second direction of rotation by causing the driving arrangement to move the object towards the second end position in a manner related to the rotary motion of the manoeuvring means if at the time when the rotation of the manoeuvring means in the second direction of rotation is initiated the object is stationary at a distance from the second end position.

5. A device according to claim 4, characterised in that the control unit (11) is arranged to respond to said closure of the first or second contact means (13a, 13b) by causing the driving arrangement to move the object all the way to the respective first or second end position if neither of the two contact means (13a, 13b) closes and the manoeuvring means (14) is not rotated during the movement of the object to the respective end position.

6. A device according to claim 4 or 5, characterised in that the control unit (1 1) is arranged to respond to rotation of the manoeuvring means (14) in the first or second direction of rotation, at a time when the object is moving towards one of the end positions after closure of the first or second contact means (13a, 13b), by causing the driving arrangement to move the object towards the respective first or second end position in a manner related to the rotary motion of the manoeuvring means.

7. A device according to any one of claims 4-6, characterised in that the control unit (1 1) is arranged to respond to said rotation of the manoeuvring means (14) in the first or second direction of rotation by causing the driving arrangement to move the object towards the respective end position at a speed which depends on the rotation speed of the manoeuvring means, preferably at a speed proportional to the rotation speed of the manoeuvring means.

8. A manoeuvring arrangement comprising a first contact means (13a), a second contact means (13b), and a toggle switch (21) which is pivotable about a pivot spindle (24), is provided with a first pressure surface (25a) on a first side of the pivot spindle (24) and a second pressure surface (25b) on the opposite second side of the pivot spindle (24) and is arranged to respond to pressure on the first pressure surface (25a) by pivoting in a first direction about the pivot spindle (24) so as to close the first contact means (13a), and to respond to pressure on the second pressure surface (25b) by pivoting in a second direction about the pivot spindle in order to close the second contact means (13b), characterised in that the manoeuvring arrangement (12) comprises a manoeuvring means (14) which is supported for rotation and which extends through a recess (29) arranged in the toggle switch (21) between said pressure surfaces (25a, 25b), and a sensor (15) for detecting rotary motion of the manoeuvring means.

9. A manoeuvring arrangement according to claim 8, characterised in that the manoeuvring means (14) is rotatable about a rotation spindle (30) which is substantially parallel with the pivot spindle (24) of the toggle switch.

10. A manoeuvring arrangement according to claim 8 or 9, characterised in that the manoeuvring means (14) has a shape of a wheel.

1 1. A manoeuvring arrangement according to any one of claims 8- 10, characterised in that the respective contact means (13a, 13b) each take the form of a circuit-breaker, preferably a microgap circuit-breaker.

12. A manoeuvring arrangement according to any one of claims 8-11 , characterised in that the sensor (15) is arranged to detect the direction of rotation and rotation speed of the manoeuvring means.

13. A manoeuvring arrangement according to claim 12, characterised in that the sensor (15) takes the form of a pulse emitter.

14. A manoeuvring arrangement according to claim 13, characterised in that the pulse emitter (15) has a spindle end (31) and the manoeuvring means (14) is fitted to, for joint rotation with, said spindle end (31) in such a way that the centreline of the spindle end constitutes the axis of rotation (30) for the manoeuvring means.