GB2053706A - Concrete mixer - Google Patents

Abstract

A horizontally disposed mixing bowl (1) contains a rotor (3) which is mounted by a shaft (4) in a bearing (5). The rotor (3) is driven by two motors (6) through respective couplings (7) and speed-reducing transmission units (8A, 8B) of which one, (8A), is coupled directly to the rotor (3) and the other (8B), to the shaft (4). The units (8A, 8B) are connected to the frame (2) by torsion bars (9) to prevent bending of the shaft (4). <IMAGE>

Description

SPECIFICATION Concrete mixer The present utility model relates to a concrete mixer of the type comprising a horizontal mixing bowl within which a rotor acts, and more specifically to the power transmission assemblies for rotating the rotor.

Concrete mixers of the above-indicated type are well known, which differ from each other by virtue of the arrangement and the number of the power sources and the associated transmission means for rotating the rotor.

The arrangements which have normally been adopted hitherto can be classified as two basic types. The first in which a single power source, of substantial size, provides for entrainment of the rotor and is connected directly to the rotary shaft thereof. In the second type, two power sources which are disposed laterally of the mixing bowl are connected to the shaft of the rotor by means of a series of grears.

Both these arrangements suffer from disadvantages insofar as, taking into account the high forces involved, a single power source gives rise to substantial problems in regard to the amount of space occupied, by virtue of its large dimensions, while the series of gears which are required to provide for the connection of two power sources gives rise to high costs, bearing in mind the fact that the gears are intended for a specific use and thus cannot be commercially obtained from those which are mass produced.

However, the need has been felt to provide an arrangement in respect of the power sources and the associated transmission means, such as to combine the advantages which derive from using two power sources of more reduced dimensions, with the advantages of direct connection which characterises the arrangements which are provided with a single power source.

The present utility model fully meets this need, by providing a concrete mixer comprising a mixing bowl and a rotor acting therein, characterised in that said rotor is actuated for rotary movement by two motor-transmission-reducing units connected to the rotor on the opposite ends of the axis thereof. In particular, one of the units is connected directly to the rotor at one side while the other acts at the other side on the free projecting end of the shaft of the rotor.

Another characteristic of the present utility model is that the two motor-transmission-reducing units are identical units which are mass produced.

The innovation will now be described in greater detail with reference to the accompanying drawing which shows an embodiment which is preferred at the present time, purely by way of example.

The drawing shows a diagrammatic front view in partial cross-section of the mixer according to the present model.

The mixer comprises a mixing bowl 1 which is supported by a frame 2 and within which there acts a rotor 3 which is capable of mixing the concrete mixture, in known manner.

The rotor 3 comprises a rotary shaft 4 which projects downwardly from the centre thereof and which rotates in a carrier 5 therefor, provided in the frame 2.

According to the present model, the rotor 3 is actuated for rotary movement by two motortransmission-reducing units, each comprising an electric motor 6 which is connected by way of a coupling means 7 to a transmission-reducing group 8A and 8B. The transmission-reducing group 8A which is disposed above the rotor 3 is connected directly thereto. The transmission-reducing group 8B however, which is disposed below the rotor and thus underneath the mixing bowl is connected to the free end of the shaft 4 of the rotor.

There are then provided two torsion bars 9 which are connected on the one hand to the reducing units 8A and 8B and on the other hand to the frame 2.

The mode of operation of the apparatus, the remainder of which is already known, is entirely evident from the accompanying drawing. In fact, the two motor-transmission-reducing groups 6, 7 and 8 which are disposed opposite each other provide for entraining the rotor 3 in rotation, which thus causes mixing of the constituents of the concrete which are introduced into the bowl 1 by means of the loading orifice 10. The couple occurring on the coupling means 7, which would be applied as a bending moment to the shaft 4 of the rotor 3, is however applied to the frame 2 by way of the two torsion bars 9.

The above-described arrangement can be embodied using motor-transmission-reducing units of standardised dimensions which are thus mass produced, with a substantial reduction in costs, while precisely by virtue of their compact dimensions, the problems relating to installation of such units are drastically reduced.

It will be apparent that equal utility can be achieved when making modifications in the abovedescribed arrangement, for example by disposing the two motors 6 on opposite sides with respect to a vertical plane passing through the axis of the rotor.

1. A concrete mixer comprising a mixing bowl and a rotor acting therein, characterised in that said rotor is actuated for rotary movement by means of two motor-transmission-reducing units which are connected to the rotor on the oppositely disposed ends of the axis thereof.

2. A mixer as set forth in 1 wherein one of the motor-transmission-reducing units is connected directly to the rotor while the other is connected to the shaft for supporting and rotating the rotor.

3. A mixer as set forth in 1 wherein the motortransmission-reducing units are identical massproduced units.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Concrete mixer The present utility model relates to a concrete mixer of the type comprising a horizontal mixing bowl within which a rotor acts, and more specifically to the power transmission assemblies for rotating the rotor. Concrete mixers of the above-indicated type are well known, which differ from each other by virtue of the arrangement and the number of the power sources and the associated transmission means for rotating the rotor. The arrangements which have normally been adopted hitherto can be classified as two basic types. The first in which a single power source, of substantial size, provides for entrainment of the rotor and is connected directly to the rotary shaft thereof. In the second type, two power sources which are disposed laterally of the mixing bowl are connected to the shaft of the rotor by means of a series of grears. Both these arrangements suffer from disadvantages insofar as, taking into account the high forces involved, a single power source gives rise to substantial problems in regard to the amount of space occupied, by virtue of its large dimensions, while the series of gears which are required to provide for the connection of two power sources gives rise to high costs, bearing in mind the fact that the gears are intended for a specific use and thus cannot be commercially obtained from those which are mass produced. However, the need has been felt to provide an arrangement in respect of the power sources and the associated transmission means, such as to combine the advantages which derive from using two power sources of more reduced dimensions, with the advantages of direct connection which characterises the arrangements which are provided with a single power source. The present utility model fully meets this need, by providing a concrete mixer comprising a mixing bowl and a rotor acting therein, characterised in that said rotor is actuated for rotary movement by two motor-transmission-reducing units connected to the rotor on the opposite ends of the axis thereof. In particular, one of the units is connected directly to the rotor at one side while the other acts at the other side on the free projecting end of the shaft of the rotor. Another characteristic of the present utility model is that the two motor-transmission-reducing units are identical units which are mass produced. The innovation will now be described in greater detail with reference to the accompanying drawing which shows an embodiment which is preferred at the present time, purely by way of example. The drawing shows a diagrammatic front view in partial cross-section of the mixer according to the present model. The mixer comprises a mixing bowl 1 which is supported by a frame 2 and within which there acts a rotor 3 which is capable of mixing the concrete mixture, in known manner. The rotor 3 comprises a rotary shaft 4 which projects downwardly from the centre thereof and which rotates in a carrier 5 therefor, provided in the frame 2. According to the present model, the rotor 3 is actuated for rotary movement by two motortransmission-reducing units, each comprising an electric motor 6 which is connected by way of a coupling means 7 to a transmission-reducing group 8A and 8B. The transmission-reducing group 8A which is disposed above the rotor 3 is connected directly thereto. The transmission-reducing group 8B however, which is disposed below the rotor and thus underneath the mixing bowl is connected to the free end of the shaft 4 of the rotor. There are then provided two torsion bars 9 which are connected on the one hand to the reducing units 8A and 8B and on the other hand to the frame 2. The mode of operation of the apparatus, the remainder of which is already known, is entirely evident from the accompanying drawing. In fact, the two motor-transmission-reducing groups 6, 7 and 8 which are disposed opposite each other provide for entraining the rotor 3 in rotation, which thus causes mixing of the constituents of the concrete which are introduced into the bowl 1 by means of the loading orifice 10. The couple occurring on the coupling means 7, which would be applied as a bending moment to the shaft 4 of the rotor 3, is however applied to the frame 2 by way of the two torsion bars 9. The above-described arrangement can be embodied using motor-transmission-reducing units of standardised dimensions which are thus mass produced, with a substantial reduction in costs, while precisely by virtue of their compact dimensions, the problems relating to installation of such units are drastically reduced. It will be apparent that equal utility can be achieved when making modifications in the abovedescribed arrangement, for example by disposing the two motors 6 on opposite sides with respect to a vertical plane passing through the axis of the rotor. CLAIMS

1. A concrete mixer comprising a mixing bowl and a rotor acting therein, characterised in that said rotor is actuated for rotary movement by means of two motor-transmission-reducing units which are connected to the rotor on the oppositely disposed ends of the axis thereof.

2. A mixer as set forth in 1 wherein one of the motor-transmission-reducing units is connected directly to the rotor while the other is connected to the shaft for supporting and rotating the rotor.

3. A mixer as set forth in 1 wherein the motortransmission-reducing units are identical massproduced units.