MOVABLE AND DISASSEMBLABLE BASEMENT FOR SCAFFOLDINGS

Abstract: The basement comprises one or two driving wheels (9) with fixed axis, associated to a propelling means (69) and a pair of steering wheels (7) combined to actuator means (46) able to drive the steering of said steering wheels; the basement can be easily disassembled for transportation requirements.

Description: The invention refers to a basement, for mobile and disassemblable scaffoldings, trestle bridges, telescopic bridges or the like, comprising at least a driving wheel having a fixed axis combined to a propelling means, and a pair of steering wheels combined to an actuator means able to drive the steering of said steering wheels. A scaffold with steering wheels and driving wheels mounted on a basement is described in US-A-3 422 922. This known scaffold comprises a rigid rectangular frame forming a basement, on which the driving and steering wheels are supported. Channel track elements and inclined channel braces are rigidly connected to the frame and extend upwardly to form a guide means for a platform frame which is vertically movable with respect to the basement. This known scaffold cannot be disassembled and is designed to be used as a vehicle. In order to carry out paintings, installation of cables for electrical systems and other similar works along both internal and external walls, there are used disassemblable scaffoldings which are movable on pivoting wheels, thus allowing an easy displacement thereof from one work position to the next. Suitable devices for a temporary locking allow a scaffolding to be fixed in the desired position. It is a common practice to use this kind of scaffoldings having remarkable weight and dimensions which, moreover, have to be moved very frequently during the execution of a work. For example, in setting up an electrical system, it is necessary to move very often the scaffolding in order to follow the trace along which the cables must be laid down. These frequent displacements are often hard and difficult. In order to ease construction and maintenance activities of the above mentioned type, it has been suggested (US-A-3 731 758) to provide a scaffold unit with a reversible drive motor and a motorized steering apparatus for the directional control of the scaffold by steering at least one support wheel. The drive motor as well as the steering actuator are mounted on the scaffolding itself, so that disassembling of the scaffolding for transportation purposes is a difficult and tedious operation. Moreover, this known arrangement is dangerous for the risk of easy turn over of the scaffolding. It is an object of the invention to provide a basement for scaffoldings, trestle bridges, telescopic bridges and the like, which overcomes the drawbacks of known scaffoldings. More particularly, it is an object of the present invention to provide a motorized basement which can be easily mounted even on existing scaffoldings, in order to motorize them, without hindering disassembling and transportation thereof. According to the invention, the basement comprises a front or steering part and a rear or driving part, which are removably connected through longitudinal beams, locking means being provided for an easy locking and releasing of said beams and of said front and rear parts of the basement. Furthermore, said front and rear parts are provided with connecting means for connecting the basement to the scaffolding, trestle bridge, telescopic bridge or the like. By using longitudinal beams of different lengths, it is possible to build up basements of different dimensions according to the specific applications the basement is used for. A series of longitudinal beams and a series of front and rear parts of different dimensions are sufficient to assemble basements of any dimension suitable for any type of application. According to a preferred embodiment, each of said front and rear part comprises a box-type structure within which the corresponding wheels and the driving members of said wheels are housed, the wheels partly projecting from the open bottom of the relevant box-type structure. This box like structure of the front and rear parts respectively allow a remarkable resistance even to torsional and bending stresses at very limited production costs and are, moreover, particularly suitable to carry out a connection with the longitudinal beams. The driving and steering wheels project only slightly from the relevant box-type structure so that, if during use a wheel comes across a pit or a depression, the scaffolding will not turn over as the basement will rest on the ground with its box-like structure. In practice, the box-type structure has an inverted U-shaped cross-section within which the wheels and driving mechanisms are housed. Further advantageous features of the basement according to the invention are set out in the appended claims. The invention also refers to a scaffolding provided with a basement as above described. The drawing shows schematically a non limiting embodiment of the invention. Fig.1 shows schematically the lower portion of a scaffolding with a basement according to the invention; Fig.2 shows a partial plan view of the steering part of the basement according to the invention; Figs.3 and 4 are section views taken on lines III-III and IV-IV of Fig.2; Fig.5 shows a partial plan view of the driving part of the basement according to the invention; and Figs. 6 and 7 show section views taken on lines VI-VI and VII-VII of Fig. 5. The basement is shown in combination with a trestle bridge, but it will be appreciated that it may be applied to telescopic bridges or to other self-propelling means as well. According to what is shown in the attached drawing, and with initial reference to Fig. 1, a mobile scaffolding 1 comprises a tubular disassemblable structure 3 of a type known per se, having in particular four uprights 3A connected to a basement generally indicated by 5, provided with four wheels 7, 9. The wheels 7, 9 are borne by two parts of the basement 5: a front or steering part, indicated by 11, and a rear or driving part, indicated by 13. The wheels 7 borne by the steering part 11 of basement 5 are pivoting wheels, that is they are movable about vertical axes thus having a steering capability, and they are combined to means able to control the steering, as described later in greater detail; while the rear wheels 9 have fixed axes and are mechanically driven to allow the scaffolding to move forward, as described in the following. Parts 11 and 13 of basement 5 are connected to each other by tubular beams 15 whose ends are received in corresponding supports 17, 19 (see in particular Figs. 2 and 4) carried by parts 11, 13 and blocked by srew members 21 provided with grips 23 to facilitate the manoeuvre thereof. The basement 5 may be easily disassembled by loosening the screw members 21 and withdrawing the beams 15 from the respective housings 17, 19. On each part 11, 13 tubular seats 25 are solidly applied (for example by welding) inside which the lower ends of the uprights 3A of structure 3 of scaffolding 1 are fitted. Possible locking members, not shown, may be provided to link the structure 3 to the basement 3. Figs. 2 to 4 show in detail the front or steering part 11 of the basement 5. As shown in these figures, part 11 comprises a box-type structure 30 with inverted U-shaped cross-section carrying the housings 17, 19 for receiving the ends of the tubular beams 15, in correspondence of which housings the screw-operated clamping means 21 are disposed. The two pivoting wheels 7 are applied to the tubular structure 30, each wheel being supported by a corresponding bracket 32, borne by a plate 33 anchored to the box-type structure 30 by screws 34 (Fig. 4), which bracket 32 rotates about a vertical axis A-A. In order to drive and control the rotation of the pivoting wheels 7 about the relevant axes A-A, a fork 36 is combined to each of said two pivoting wheels 7, which engages the respective pivoting wheel in correspondence of the rotation axis thereof. The two forks 36 (one only being shown in the drawing, the other being exactly alike) are hinged through an articulation 40 to relevant arms or connecting rods 38, which are in turn hinged, at the opposite end with respect to fork 36, to a crank 44 through an articulation 42 similar to articulation 40. The crank 44 rotates about a vertical axis B by an electrical motor 46, through a joint 48 and a reduction gear 50. The electrical motor 46, powered by a battery 52 carried by the same basement (Fig. 1), drives into rotation the crank 44 according to double arrow f44 in clockwise or anti-clockwise direction according to the command given by the operator, so as to allow the basement and the whole scaffolding to steer in one direction or the other as required. The control of the motor is made through a console 54 (Fig. 1) carried by the structure 3 of the scaffolding 1, at a level suitable for an easy access by an operator standing on the ground or by an operator standing on the scaffolding, a sufficiently long cable being provided to displace the console from one position to another. On said console lever or bottom means or similar are provided for controlling the rotation of the electrical motor 46. Moreover, an indicator of the charge level of the battery 52 and an indicator of the position of the steering wheels may also be provided. To indicate the position of the steering wheels there may be provided analog and digital transducer means of known type which detect the position of crank 44. For example, and in a particularly simple embodiment, said position transducer means may comprise a potentiometer able to detect the angular position of the crank 44. Figs. 5 to 7 illustrate a possible embodiment of the rear part 13 of basement 5, which carries the propelling means for causing the advancement of the self-propelling scaffolding. As shown in these figures, the rear or driving part 13 comprise a box-type structure 60 equal or similar to the box-type structure 30 carrying the housings 17, 19 for the tubular beams 15. The box-type structure 60 is provided at its ends with closing plates 61 solidly engaged to said box-type structure 60. The plates 61 carry supports 63 for the ends of a shaft 65 on which the driving wheels 9 are fitted. The shaft 65 is driven into rotation by a geared motor 67 comprising an electrical motor 69, said geared motor being supported by a bracket 71 achored to the box-type structure 60. The electrical motor 69 is powered by battery 52 and is put into operation by lever, button or similar means disposed on console 54. Moreover, the motor 69 can be driven into rotation in both directions to allow the movement of the scaffolding in forward or backward direction. Instead of two driving wheels 9, there may be provided, in the rear part of basement 5, a single driving wheel connected to a geared motor and a wheel idly mounted in the box-type structure coaxially to the driving wheel. The basement 5 is provided with means of known type and schematically indicated by 73 of Fig. 1 for securing the scaffolding on the ground. The motor 69 is also able to act as safety means against accidental movements of the basement and thus of the scaffolding. In fact, the velocity ratio between said motor and the driving wheels is very high, in the order of 1:70, so that the transmission is in practice irreversible. Moreover, it is also possible to provide a self-braking motor. Also the reduction ratio of geared motor 46 is extremely high so that the transmission is irreversible and, moreover, also in this case a self-braking motor may be provided. The basement according to the invention is extremely practical in that it allows the scaffolding associated thereto to be easily moved without exerting any appreciable efforts, and in that it is further provided with safety devices as required for its use. This being particularly useful in case of works which call for frequent displacements of even heavy scaffoldings. The basement according to the invention can be easily disassembled thus allowing a ready transfer thereof. To this end, it is sufficient, after having disengaged the scaffolding from the basement, to loosen the screw members 21 and withdraw the tubular beam 15 from their seats. The drawing shows only an exemple of the invention, which may vary in the forms and dispositions.

Claims: 1. A basement for mobile and disassemblable scaffoldings, trestle bridges, telescopic bridges or the like, comprising at least a driving wheel (9) having a fixed axis (65) combined to a propelling means (67, 69), and a pair of steering wheels (7) combined to an actuator means (46, 50) able to drive the steering of said steering wheels (7), characterized in that it comprises a front or steering part (11) and a rear or driving part (13), which are removably connected through longitudinal beams (15), locking means (21, 23) being provided for an easy locking and releasing of said beams (15) and of said front (11) and rear (13) parts of the basement, and that said front and rear parts are provided with connecting means (25) for connecting the basement to the scaffolding, trestle bridge, telescopic bridge or the like. 2. Basement according to claim 1, characterized in that each of said front and rear part (11, 13) comprises a box-type structure (30, 60) within which the corresponding wheels (7, 9) and the driving members of said wheels are housed, the wheels partly projecting from the open bottom of the relevant box-type structure. 3. Basement according to claim 2, characterized in that said box-type structure has an inverted U-shaped cross-section, from which the wheels project by a fraction of their own radius. 4. Basement according to one or more preceding claims, characterized in that said propelling means (67, 69) is a d.c. geared motor. 5. Basement according to one or more preceding claims, characterized in that said actuator means (46, 50) for driving the steering wheels comprise a d.c. electrical motor (46). 6. Basement according to one or more preceding claims, characterized in that said steering wheels (7) are wheels pivoting about a vertical axis (A-A) and that to each of said wheels (7) a fork (36) is associated, which is connected to an articulated system (38, 44) for the transmission of the movement from said actuator means (46, 50) to said steering wheels (7). 7. Basement according to one or more preceding claims, characterized in that to said actuator means (46, 50) for driving the steering wheels there are combined position transducer means for detecting the position of the steering wheels. 8. Mobile and disassemblable scaffolding, characterized in that it comprises a basement according to one or more preceding claims.

Inventors: VENTURINI, FABRIZIO
Applicants: VENTURINI, FABRIZIO
Application year: 1989
Main classification: E04G1
IPC codes: E04G1