BACKGROUND OF THE INVENTION

The invention relates to a rolling scaffold, in particular a rolling scaffold to be used in interior areas, in particular for the finishing work, including plastering and painting.

In the finishing work a rolling scaffold is often used on which a workman can stand in order to perform his work at higher levels, such as a ceiling, in a stable manner. The rolling scaffold comprises a (main)frame, usually having two upright ladder-like end frames and ledgers extending in between them, as well as an elongated platform supported on the end frames and adjustable as to height. The frame usually is supported by a set of four swivel casters, disposed at the corners, and each provided with a foot- activated brake.

When carrying out the job the location of work will often be moved. The workman will then have to put his tools stably away, climb down the scaffold, release the swivel casters, move the scaffold to the desired location, secure the swivel casters again and climb up the scaffold. This requires a lot of time and effort that cannot be put into the actual job. This procedure also has to be followed when the scaffold's position needs to be slightly corrected or altered. Climbing up and down the scaffold is physically taxing to the workman and also exposes him to the risk of falling. In case of jerking motions during moving the rolling scaffold, there is furthermore the risk of tools falling down from the roiling scaffold, possibly hitting the workman or breaking on the floor. SUMMARY OF THE INVENTION

It is an object of the invention to provide a rolling scaffold assembly, in particular intended to be used for finishing interior areas, which scaffold can be moved without a workman having to leave the platform

It is an object of the invention to provide a rolling scaffold assembly, in particular intended to be used for finishing interior areas, which scaffold can be moved in a reliable and/or controlled manner.

It is an object of the invention to provide a rolling scaffold assembly, in particular intended to be used for finishing interior areas, which scaffold is safe to use.

It is an object of the invention to provide a rolling scaffold assembly, in particular intended to be used for finishing interior areas, which scaffold is versatile. For achieving at least one of these objects the invention, according to one aspect, provides a rolling scaffold assembly comprising a rolling scaffold having a platform, a platform-carrying frame and a set of supporting wheels for supporting the frame in a rolling manner, further comprising a remote controllable drive apparatus, a manually operable, preferably wirelessly operable, preferably hand-held, remote control device for it, wherein the drive apparatus is formed by a caterpillar vehicle having a vehicle frame carrying an arrangement of self-braking electromotors and a battery for its power supply, and having two adjacently positioned caterpillar tracks carrying the vehicle frame, which tracks can be driven independent of each other by the related electromotors.

In that way the workman can remain on the platform for moving the rolling scaffold. The workman does not need to spend time and energy on climbing up and down the rolling scaffold. He will not need to put the tools away with particular care. The caterpillar tracks provide a proper grip, practically non-skid, on the floor surface even if debris, such as grit and mortar lie scattered on it. Due to the drive apparatus being self-braking, safety against undesired movement of the rolling scaffold is guaranteed and blocking (and thus unblocking as well) the supporting wheels is not required. If the remote control device can be hand-held, the workman is free to choose a position of overview on the platform during activating the caterpillar vehicle.

The finishing work usually takes several days. The rolling scaffold is usually left behind for the next workday. In order to prevent unauthorised people from taking away the drive apparatus, the frame and the drive apparatus according to a further embodiment are provided with first and second coupling means, respectively, for coupling the frame and the drive apparatus, wherein the first and second coupling means can selectively be brought in and out of coupling with each other. The drive apparatus can then be detached and stowed away by the workman or be taken along in a company van or be stowed away in a locked place until the next workday. The first coupling means can be attached to a part in the lower section of the frame, such as one or more longitudinal tubes of the frame. Said longitudinal tubes may for instance extend in between the known upright end frames mentioned in the preamble.

In a simple embodiment the first and second coupling means form an insertion coupling, in particular a pin and hole coupling, more in particular a pin and bush coupling. In order to be coupled both coupling means or coupling members can simply be inserted into each other.

Preferably the first and second coupling means are adapted for coupling and uncoupling with each other in vertical direction. In case of the said pin and hole/bush coupling this can be done by inserting a pin in a hole, in particular a bush, in vertical direction and removing it therefrom in opposite direction. Due to the vertical insertion direction the coupling can be realised without locking. A workman does not have to bend under the scaffold to couple or uncouple. Preferably the pin is snugly accommodated in the bush resulting in the pin being oriented by the bush. The pin may be straight circle cylindrical, the bush being formed to match.

In one embodiment the pin or the bush, or the bush or the pin, is hinged to the rolling scaffold frame or vehicle frame. Preferably, however, the pin and/or the bush (or alternatively the bush and/or the pin) are angle-rigidly attached to the frame of the rolling scaffold and the vehicle frame, respectively. For enhancing the drive apparatus to follow the floor surface in case it has irregularities in there, such as pits and bulges, the first and second coupling means in the coupled condition can still be moved relative to each other in the vertical sense. Contact with the floor is enhanced if a spring is active between the first and second coupling means for exerting a downward pressure on the second coupling means.

The spring can be accommodated in the said bush, and can be guided by it. In one embodiment the bush is part of the first coupling means, in which case the opening is oriented downward and no dirt can end up in the bush which might otherwise hamper the spring action.

In one embodiment the first and second coupling means can be coupled without locking the coupling. For instance the coupling can easily be effected by simply inserting or sliding in the pin into the hole or the bush. In the coupled condition the pin can be slidable in pin direction relative to the hole or bush.

The first and second coupling means can form a rotation coupling for mutual relative rotation about a vertical centre line of rotation. In that way the pin can be rotatable in the hole, in particular bush.

Generally for enhancing the manoeuvrability of the rolling scaffold, by operating the remote control device, the drive apparatus can be rotated relative to the frame about a vertical centre line of rotation. In one embodiment said centre line passes through the centre of the assembly of both caterpillar tracks as seen from above. In case of said rotation coupling both vertical centre lines of rotation coincide. The drive apparatus in the said rotation (relative to the frame) can have a circumscribed circle, which circle considered in top view of the frame is situated within the contours of the frame, preferably within the contours of the platform, so that the workman can keep the dimensions of the rolling scaffold he knows as starting point and the drive apparatus is largely protected by the rolling scaffold.

In one embodiment the frame of the rolling scaffold, as is usual, is elongated in top view, having two longitudinal halves on both sides of a centre (Z), wherein according to the invention at least more than half the drive apparatus, at least with the said rotation coupling or centre line of rotation, can be situated within a longitudinal half of the rolling scaffold in said top view. This enhances the manoeuvrability of the rolling scaffold. In particular the drive apparatus can be situated entirely within said longitudinal half, in the top view.

The rolling scaffold frame may have a vertical longitudinal centre plane, wherein the vertical centre line of rotation preferably is situated in the longitudinal centre plane.

The controllability of the movement of the rolling scaffold is further enhanced if the platform defines a standing/walking surface for the workman, wherein a part of the standing/walking surface that is situated above, preferably straight above the drive apparatus, differs from the rest of the standing/walking surface and forms a window. The workman is then able to monitor the movement of the drive apparatus from a safe position on the standing/walking surface, so without having to lean over the railing. It is particularly advantageous in this embodiment if at the upper side the drive apparatus is provided with an indication of a main direction, front/rear side of the drive apparatus, which indication can be seen from above, and the manually operable remote control device is provided with operating means such as, keys, buttons and the like of which at least one is provided with an indication of a main driving direction, that means forward or rearward, wherein "forward" is preferred. The workman is able to see immediately in which direction the drive apparatus will move when he operates the button in question.

The manoeuvrability is also enhanced if the set of supporting wheels comprises a number of swivel casters and at least one rigid caster. In case the set of supporting wheels comprises only one rigid caster this forms a single point of rotation for the rolling scaffold, thus enabling the workman to control the displacement even better. The rigid caster preferably is situated in the other longitudinal half than the one in which more than half the drive apparatus or the vertical centre line of rotation is situated. The manoeuvrability is further enhanced if, in the aforementioned case of the drive apparatus being placed in the said longitudinal half, the supporting wheels in said longitudinal half are swivel casters.

The choice for the manner of movement is enhanced if the set of supporting wheels comprises one or more casters which if so desired can swivel or be secured against swivelling, preferably in a chosen orientation.

According to a further aspect the invention provides a caterpillar vehicle apparently suitable and intended for a rolling scaffold according to the invention. Preferably at the upper side of the vehicle frame the caterpillar vehicle is provided with a pin or hole, in particular bush, as second coupling means.

According to a further aspect the invention provides a rolling scaffold assembly comprising a rolling scaffold having a platform, a platform- carrying frame and a set of supporting wheels for supporting the frame in a rolling manner, further comprising a remote controllable drive apparatus, and a manually operable, preferably hand-held, remote control device for it, wherein the drive apparatus is formed by a mobile vehicle including a vehicle frame, wherein the frame of the rolling scaffold and the drive apparatus are provided with first and second coupling means, respectively, for coupling the rolling scaffold frame and the drive apparatus, wherein the first and second coupling means form an insertion coupling and can selectively be brought into and out of insertion coupling with each other in a vertical motion.

Further embodiments thereof are described in the attached claims 28-46, the contents of which should be considered inserted herein.

According to a further aspect the invention provides a rolling scaffold provided with wheels at the corners, wherein at three of the four corners swivel casters have been arranged, and at one corner a rigid caster has been arranged.

According to a further aspect the invention provides a method for using a rolling scaffold assembly according to the invention.

In one embodiment wherein use is made of said first and second coupling means with vertical insertion coupling, the first and second coupling means are not locked relative to each other against release, so that a vertical mutual movement is possible and irregularities in the floor surface can be followed.

In one embodiment coupling and uncoupling takes place by lifting the rolling scaffold, preferably at one longitudinal end thereof. In the said case of drive apparatus situated out of the longitudinal centre of the rolling scaffold this will preferably be the longitudinal end that is situated closest to the coupling between rolling scaffold frame and drive apparatus.

According to a further aspect the invention provides a method for moving a rolling scaffold, wherein a caterpillar vehicle is coupled to the rolling scaffold frame in a manner so as to be rotatable about a vertical centre line of rotation, such that, considered in a longitudinal direction of the rolling scaffold, the centre line of rotation is situated off-centre relative to the centre of the rolling scaffold, wherein a wheel of the rolling scaffold on the side of the centre opposite to the side of the vertical centre line of rotation is used as rigid caster and the caterpillar vehicle is activated for swinging the rolling scaffold about a point of rotation at the location of the rigid caster.

The aspects and measures described in this description and the claims of the application and/or shown in the drawings of this application may where possible also be used individually. Said individual aspects may be the subject of divisional patent applications relating thereto. This particularly applies to the measures and aspects that are described per se in the sub claims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be elucidated on the basis of a number of exemplary embodiments shown in the attached drawings, in which: Figure 1 is an inclined side view of an exemplary embodiment of a rolling scaffold according to the invention;

Figure 2 is a detail in side view of the coupling between a drive apparatus and the frame of the rolling scaffold of figure 1 ;

Figure 3 is a top view of a part of the rolling scaffold of figure 1 ;

Figure 4 is a top view of a remote control for the drive apparatus; and Figures 5A-C show a side view according to figure 2, a top view and an inclined side view of the lower section of a second exemplary embodiment of a rolling scaffold according to the invention, respectively.

DETAILED DESCRIPTION OF THE DRAWINGS

The rolling scaffold 1 in figure 1 comprises an in top view elongated frame 2 with upright end frames 3a, b with corner uprights 4 and transverse tubes 5. On the frame 2 a platform is supported, placed on transverse tubes 5, at a height desired for the job. Towards the longitudinal ends the space above the platform 6 is shielded by the end frames 3a, b and safe from falling towards both sides by longitudinal tube 7 and two fence members 8 attached to the uprights 4 and hinged to each other in order to form a so- called foldable scaffold. The ladder-shaped end frames 3a, b can be used by the workman to climb up and down the scaffold. The frame 2 has a longitudinal centre plane M that runs right through the centre of end frames 3a,b. The depicted rolling scaffold 1 can for instance be 0.9 m wide and 2 m long and have a height of 2.4 m. Below the platform 6, in the lower section of the frame 2, end frames 3a, b are furthermore connected to each other by a longitudinal tube 9. From a point situated in a longitudinal half 2a of the frame, the longitudinal tube 9, at approximately ¼ of the length of the longitudinal tube 9, is connected to the nearest end frame 3a by two shores 10. The junction 1 of shores 10 and longitudinal tube 9 is thus fixed. Z indicates the centre between both end frames 3a, b, the notional transition between longitudinal half 2a and longitudinal half 2b.

The frame 2 is supported on a floor 100 by means of three swivel casters 12 and one rigid caster 13. The rigid caster 13 is situated below the end frame 3b that is situated farthest from the junction 1. In one embodiment the swivel casters are equipped to be placed in a chosen one of two conditions, namely a free swivelling condition and a condition blocked against swivelling, in which case the caster temporarily is a rigid caster, albeit placed in a desired orientation The platform 6 provides a substantially closed surface. It can be formed by a solid board 6a, or by a board provided with holes for dirt/drainage, as is common for scaffold boards. In said longitudinal half 2a, however, a walkable window 14 has been left free, over the junction 1 1 , which window may be formed by a grid or transparent plate, for instance of Lexan plate.

The rolling scaffold assembly further comprises a drive apparatus in the form of a caterpillar vehicle 20 with vehicle frame 21 and two caterpillar tracks 22, preferably so-called non-marking caterpillar tracks, which drive apparatus is positioned below the platform 6, coupled to the longitudinal tube 9. For that purpose an attachment plate 15, see figure 2, is welded to the bottom side of the junction 1 1 , on which attachment plate a downwardly extending first, vertically extending coupling means, a straight circle cylindrical coupling bush 16, is attached fixedly and angle-rigidly. Angle- rigidly means that the orientation of the coupling bush relative to the plate 15 and thus relative to the longitudinal tube, in this case 90 degrees, is preserved under the forces that arise. Between the plate 15 and the coupling bush 16 reinforcements 15a have been arranged. In the coupling bush 16 a spring 18 is accommodated, which spring is attached with its upper end to the plate 15 and with its lower end supports against a small plate 19a forming a unity with a bush 19 that can be slid up and down within the coupling bush 16, for guiding/confining the lower end of the spring 18. The small plate 19a is stopped from falling out of the coupling bush 16 by circumferential shoulder edge 16a. At the upper side of the frame 21 of the caterpillar vehicle 20 a second, vertically extending coupling means, a straight circle cylindrical coupling pin 17, is attached fixedly and angle- rigidly. Angle-rigidly means that the orientation of the coupling pin relative to the upper side of the frame 21 , in this case 90 degrees, is preserved under the forces that arise. In figure 2 the coupling pin 17, together with coupling bush 16 forming a insertion coupling or slide coupling that can be detached or uncoupled, is snugly and in a guided manner accommodated in the lower portion 16b of the coupling bush 16, such that the coupling pin 17 is rotatable about a vertical centre line of rotation Y within the coupling bush 16, wherein the upper end of the coupling pin 17 slides over the bottom surface of the small plate 19a, and the coupling pin 17 can be moved up and down within the bush 16, guided/oriented by the bush portion 16b. In use, the coupling pin 17 always extends with its upper end above the shoulder 16a, so that -via small plate 19a- a pressure force is constantly exerted by spring 18 on the coupling pin 17 and thus on the caterpillar vehicle 20. This enhances the contact of the caterpillar tracks 22 with the floor surface in case of an irregular floor surface, having elevations or recesses/pits, when the caterpillar tracks need to make contact with the ascending/descending surfaces in the floor. The coupling pin 17 can be slid out of the coupling bush 16 by the workman in order to remove the caterpillar vehicle 20 from the rolling scaffold 1.

The location of the coupling 16/17 and thus the location of the vertical centre line of rotation Y is spaced apart from the centre Z, in longitudinal half 2a, in the vertical longitudinal centre plane M. The vertical centre line Y passes through the centre S of the two caterpillar tracks 22, in top view. In an alternative embodiment, not shown, the vertical centre line Y is spaced apart from S, so that atop the vehicle frame room is created for a removable battery.

The two caterpillar tracks 22 supporting the frame 21 of the caterpillar vehicle 20 are each independently driven by their own, self-braking, reversible electromotor (for instance with a power of 850 kg each), not shown, accommodated in the frame 21. A rechargeable, optionally detachable battery (for instance 12V) is provided for the power supply of the motors. The electromotors may be adapted for operating at two speeds, namely a low manoeuvring speed of the caterpillar tracks of 2 km/h and a high movement speed of 9 km/h. At starting from a standstill they operate at a so-called soft start, so that the acceleration is not an abrupt one. The frame 21 furthermore carries a receiver 23 having a control unit 24, with which the operation of the motors for the caterpillar tracks 22 can be controlled. At the upper side of the frame 21 arrows A have been disposed, indicating a main direction parallel to the caterpillar tracks 22, in this case forward. The caterpillar tracks can in general be so-called non-marking tyres, leaving no black marks on the floor which is advantageous in case the floor has already been finished.

The rolling scaffold assembly furthermore comprises a remote control 30 having a transmitter 31 by which means the control unit 24 can be operated in a wireless manner. During the job, the remote control 30 can be hung from a tube of the rolling scaffold 1 , for instance tube 7. The remote control 30 (see figure 4) has an emergency stop button 32 and buttons 33-36 for, respectively, activating both caterpillar tracks 22, in the forward direction or the rearward direction, and for activating both caterpillar tracks 22 simultaneously, in one type of mutually opposing directions and in an opposite type of opposing directions, respectively. In case of said multiple speeds a selector button is provided for that as well, jointly for both electromotors/caterpillar tracks. An indicator for the rechargeable battery of the caterpillar vehicle is furthermore present. If the caterpillar vehicle is provided with a so-called kill-switch the remote control can be provided with a button to overrule it and without having to climb down the scaffold reactivating the caterpillar vehicle again. As caterpillar vehicle 20, in principle a caterpillar vehicle of the type described in WO 2008/000257, with a few alterations, can for instance be started from. Its caterpillar tracks, known from the CamperTrolley corresponding with said patent application, can be suitable for use as caterpillar tracks in a caterpillar vehicle according to the invention. The caterpillar vehicle 20 may for instance have a length and width of 0.4 m and a height (without pin) of 0.2 m, and be easy to take along and stow away. In operation the workman P standing on the platform 6 is in the process of for instance plastering an upper section of a wall. To continue plastering, the platform 6 needs to be moved. The workman P takes the remote control 30 and operates the button(s) required for the desired drive direction. This may be forward, rearward, turning anticlockwise or turning clockwise, in a desired sequence. Through the window 14 the workman P can see the orientation of the arrows A on the top of the vehicle frame 21 and therefore know what the consequences of operating the buttons on the remote control 30 will be. When pressing button 33 the vehicle 20 will drive forward in direction A.

The caterpillar vehicle 20 is able to rotate relative to the coupling bush 16 about line Y, with a circumscribed circle B indicated in figure 3, which circle is situated within the contour of the frame 2, even within the contour of the platform 6. In the aforementioned alternative embodiment of some distance between centre line Y and centre S the vehicle can be designed such that the circumscribed circle is also situated within those contours.

The rolling scaffold 1 can furthermore rotate as a whole in the horizontal plane about a point of rotation formed by rigid caster 13, see rotation curve C, figure 3 (note that the swivel casters 12 are not shown).

Thus the workman P is able to move the rolling scaffold 1 in a controlled manner with overview and remaining on the platform 6, shielded all round, to a next work location and manoeuvre at that location -at a lower speed- . After the caterpillar vehicle has stopped the self-braking property of the motors combined with the caterpillar tracks' high grip on the floor ensures sufficiently reliable resistance against displacement of the rolling scaffold 1 and thus stability. In the condition shown in figure 1 the rigid caster 13 contributes to the resistance against transverse displacement. The workman P need not climb down the rolling scaffold to put a brake on the wheels.

At the end of the workday the workman P climbs down the rolling scaffold , lifts the rolling scaffold 1 at the end frame 3a of longitudinal half 2a over a little distance in order to allow the coupling pin 17 to come out of the coupling bush 16 and moves the rolling scaffold 1 slightly in transverse direction to take the coupling pin 17 out of the vertical line with coupling bush 16. This requires little effort. After putting the rolling scaffold down again, the workman can then pick up the caterpillar vehicle 20 and take it along in a company van, so that the caterpillar vehicle cannot be stolen from work, or place the caterpillar vehicle in a locked cabinet. The next day he simply reconnects the caterpillar vehicle 20 before climbing up the rolling scaffold 1 again and resume working. The caterpillar vehicle 20 is then placed below the rolling scaffold 1 , close to the coupling bush 16, subsequently the workman lifts the rolling scaffold at the end frame 3a of the longitudinal half 2a to such an extent that the lower edge of the coupling bush 16 arrives just above the upper side of the coupling pin 17, the workman then moves the rolling scaffold 1 to such an extent that the coupling bush 16 is above the coupling pin 17 and finally he lowers the rolling scaffold again wherein the coupling bush 16 slides over the coupling pin 17 and the coupling is effected. The off-centre location of the coupling relative to the centre Z facilitates the uncoupling and coupling. The workman P does not need to bend down below the scaffold for coupling/uncoupling. When not being used the battery can be recharged, for instance by connecting it to the battery of a company van.

The rolling scaffold 1 is easily adapted by attaching longitudinal tube 9, shores 10 and coupling bush 16 thereto. Other existing rolling scaffolds can also easily be adapted to enable the coupling to caterpillar vehicle.

In an alternative, simple embodiment the coupling bush 16 is fixedly attached to two transverse tubes 10 by two small plates 1 1 , see figures 5A- C, which tubes 10 for instance have been attached to two longitudinal tubes 9a, b by two clamping sleeves 10a, b that can be screwed on, which longitudinal tubes have for instance been attached to the end frames 3a, b by quick snap couplings. The assembly of longitudinal tubes 9a, b and transverse tubes 10, 10 including the coupling bush 16 attached thereon can easily be made. The insertion coupling 16, 17 substantially corresponds with the insertion coupling of figure 2. The caterpillar tracks are schematically shown here, it will be understood that they have been provided with a profile, like in figure 2. The rolling scaffold with which the caterpillar vehicle according to the invention can be coupled, can also be larger than the relatively small rolling scaffold 2 depicted. The invention can for instance also be applied to larger rolling scaffolds, having heights in excess of 2.5 m, for instance having a width of 1.2 m and a length of 3 m.

The above description is included to illustrate the operation of preferred embodiments of the invention and not to limit the scope of the invention. Starting from the above explanation many variations that fall within the spirit and scope of the present invention will be evident to an expert.