Abstract:
In an arrangement comprising a motor/pump unit and a sound-deadening cover, the sound-deadening cover absorbs the airborne noise emitted by the motor/pump unit. On the other hand, the sound-deadening cover acts like the diaphragm of a loudspeaker for the structureborne noise emanating from the motor/pump unit. In order to absorb the structureborne noise as well, the sound-deadening cover is constructed as a sound-deadening hood, and is placed over the motor/pump unit in the operating condition, without touching it. During transportation, the sound-deadening hood and the motor/pump unit are supported on one another. The arrangement is used to absorb sound from units comprising a pump and a motor driving the latter.

Description:
FIELD AND BACKGROUND OF THE INVENTION 
     The invention relates to an arrangement for absorbing the sound emanating from a motor/pump unit, having a sound-deadening cover for the motor/pump unit. 
     An arrangement of this kind is known from U.S. Pat. No. 5,354,182. The motor/pump unit is surrounded by a sound-deadening cover. The motor/pump unit and the sound-deadening cover are held against one another. Angle pieces are screwed to the housing of the motor, being used to fix the motor/pump unit to an underlying support structure. Although an arrangement of this kind absorbs the airborne noise emitted by the motor/pump unit, the structureborne noise emanating from the motor/pump unit is transmitted to the cover and radiated to the outside. The cover, which deadens the airborne noise, acts like the diaphragm of a loudspeaker. This means that the larger the surface of the cover, the more sound is radiated. 
     The object on which the invention is based is to provide an arrangement of the type stated at the outset that not only absorbs airborne noise but also absorbs structureborne noise. 
     SUMMARY OF THE INVENTION 
     By the invention since the motor/pump unit and the sound-deadening hood do not touch one another in the operating condition, the structureborne noise of the motor/pump unit is not transmitted to the sound-deadening hood. On the other hand, however, since the motor/pump unit and the sound-deadening hood are supported on one another during transportation, they can be transported jointly in a simple manner. 
     Advantageous developments of the invention are provided. The catches for the joint transportation of the motor/pump unit and the sound-deadening hood are advantageously constructed in such a way that the motor/pump unit is held against the sound-deadening hood or that the sound-deadening hood is held against the motor/pump unit during transportation. If the catches are constructed in such a way that they engage in one another in a self-centering manner during the raising operation, the motor/pump unit and the sound-deadening hood cannot slip relative to one another during transportation. It is advantageous to provide one catch with a frustoconical outer surface and the other catch with a corresponding frustoconical inner surface. As an additional safeguard against vibration, a screwed joint is provided, which is passed through the catches. If the screwed joint is provided with transportation lugs at the head end, points of engagement for lifting gear are obtained in a simple manner. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is explained in greater detail below together with its further details by means of an exemplary embodiment illustrated in the drawings, in which: 
     FIG. 1 shows a first arrangement for absorbing the sound emanating from a motor/pump unit in schematic representation, 
     FIG. 2 shows a second arrangement for absorbing the sound emanating from a motor/pump unit in schematic representation, 
     FIG. 3 shows a detailed illustration of the arrangement shown in FIG.  2  and 
     FIG. 4 shows a detail of the arrangement illustrated in FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Identical components are provided with identical reference numerals. 
     FIG. 1 shows a first arrangement according to the invention for absorbing the sound emanating from a motor/pump unit  1  in schematic representation. Two pumps  3  and  4  are held mechanically on an electric motor  2 . The pumps  3  and  4  are driven by the electric motor  2 . The electric motor  2  is held on a base plate  5 . The base plate  5  is held on an underlying support structure  8 , which is illustrated only schematically, by means of elastic fastening means, which are here illustrated as springs  6  and  7 . The underlying support structure  8  can, for example, be a floor in a building, in which the motor/pump unit has been set up, or the frame of a machine into which the motor/pump unit is integrated. A sound-deadening hood  9  is placed over the motor/pump unit  1 , surrounding the motor/pump unit  1  without touching it. The sound-deadening hood  9  absorbs the airborne noise of the motor/pump unit  1 . An encircling interlayer  10  in the form of a strip is arranged between the sound-deadening hood  9  and the underlying support structure  8 . The interlayer  10  is composed of a flexible material, e.g. rubber or foam. It is used to provide sound absorption between the underlying support structure  8  and the interlayer  10 . Angular catches  11  and  12  are connected to the sound-deadening hood  9 . Further angular catches  13  and  14  are held on the housing of the pump  4  and on the housing of the electric motor  2 . The catches  11  to  14  are provided with guides, which engage in one another in a self-centering manner as the sound-deadening hood  9  is raised. The catches  11  and  12  are additionally provided with transportation lugs  15  and  16 . In the operating condition of the arrangement according to the invention, which is illustrated in FIG. 1, the motor/pump unit  1  and the sound-deadening hood  9  are each supported independently on the underlying support structure  8 . Here, the sound-deadening hood  9  is placed over the motor/pump unit  1  without touching it. If the motor/pump unit  1  and the sound-deadening hood  9  are to be transported, the sound-deadening hood  9  is first of all raised by the transportation lugs  15  and  16  until catches  11  and  13  and catches  12  and  14  engage. During this process, the self-centering construction of the guide surfaces of the catches  11  to  14  ensures a defined position of the motor/pump unit  1  relative to the sound-deadening hood  9 . If the arrangement is lowered again, the motor/pump unit  1  comes to rest on the underlying support structure  8  first. As the sound-deadening hood  9  is lowered further, catches  11  and  13  and  12  and  14  disengage and the sound-deadening hood  9  then likewise comes to rest on the underlying support structure  8 . 
     FIG. 2 shows a second arrangement according to the invention for absorbing the sound emanating from a motor/pump unit  1 , in schematic form. As in FIG. 1, the pumps  3  and  4  are held mechanically on the electric motor  2  and are driven by the latter. The base plate  5 , on which the electric motor  2  is held, is provided with four lugs, of which only the lugs provided with the reference numerals  20  and  21  are visible in FIG.  2 . They conceal two further lugs. The lugs are used to receive bars, by means of which the motor/pump unit  1  is raised and transported like a sedan chair, for example. Here too, the sound-deadening hood  9  is placed over the motor/pump unit  1  in such a way that it surrounds it without touching it. Catches  22  and  23  are held on the sound-deadening hood  9 . Further catches  24  and  25  are held on the housing of the pump  4  and on the housing of the electric motor  2 . The catches  22  to  25  are provided with guides, which engage in one another in a self-centering manner when the motor/pump unit  1  is raised. In the operating condition of the arrangement according to the invention, which is illustrated in FIG. 2, the motor/pump unit  1  and the sound-deadening hood  9  are each supported independently of one another on the underlying support structure  8 , without touching one another. If the motor/pump unit  1  and the sound-deadening hood  9  are to be transported, the sound-deadening hood  9  is opened on opposite sides, allowing bars to be pushed through the lugs  20  and  21 . The bars are raised until catch  22  rests on catch  24  and catch  23  rests on catch  25 . During this process, the self-centering construction of the guide surfaces of the catches  22  to  25  ensures a defined position of the motor/pump unit  1  relative to the sound-deadening hood  9 . If the arrangement is lowered again, the sound-deadening hood  9  comes to rest on the underlying support structure  8  first. As the motor/pump unit  1  is lowered further, catches  22  and  24  and  23  and  25  disengage and the motor/pump unit  1  then likewise comes to rest on the underlying support structure  8 . 
     FIG. 3 shows a detailed illustration of the arrangement in FIG. 2, especially as regards the construction of the catches  22  to  25 . In this exemplary embodiment, the base plate  5  is held on the underlying support structure via damping mounts, of which only damping mounts  26  and  27  can be seen in FIG.  3 . Damping mounts are used for the elastic fixing of components. Catches  22  and  23  are constructed as catch sleeves with frustoconical inner surfaces  22   i  and  23   i . Catches  24  and  25  are constructed as catch pins with frustoconical outer surfaces  24   a  and  25   a . If the base plate  5  is raised—as described above—catch pin  24  engages in catch sleeve  22  and catch pin  25  engages in catch sleeve  23 . In this arrangement, the frustoconical outer surfaces  24   i  and  25   i  of catch pins  24  and  25  are enclosed in a self-centering manner by the frustoconical inner surfaces  22   i  and  23   i  of catch sleeves  22  and  23 . This configuration of the catches  22  to  25  prevents the sound-deadening hood  9  from slipping sideways relative to the motor/pump unit. Catch sleeves  22  and  23  are provided with central through holes  28  and  29 . Catch pins  24  and  25  are each provided with an internal thread  30  and  31  respectively. Screws, which are passed through the through holes  28  and  29  and are screwed into the internal threads  30  and  31 , hold the motor/pump unit  1  firmly in the raised position on the sound-deadening hood  9 . When the motor/pump unit  1  has been screwed to the sound-deadening hood  9 , the bars by means of which the motor/pump unit  1  has been raised can be removed. 
     In FIG. 4, the detail X indicated in FIG. 3 is shown on an enlarged scale. FIG. 4 shows a fragmentary view of the sound-deadening hood  9 , catch sleeve  23 , catch pin  25  and a screw  32 . The screw  32  is provided with an external thread  33 . The head of the screw  32  is constructed as a transportation lug  34 . If the motor/pump unit  1  is raised, catch sleeve  23  rests on catch pin  25 . If the screw  32  is passed through the through hole  29  in catch sleeve  23  and screwed into the internal thread  31  of catch pin  25 , the motor/pump unit  1  is held firmly on the sound-deadening hood  9 . In the same way, another screw, which is not shown in FIG. 3, is passed through the through hole  28  in catch sleeve  22  and screwed into the internal thread  30  of catch pin  24 . Even when there are shocks during transportation, the motor/pump unit  1  is now held securely on the sound-deadening hood  1 . The bars that have been passed through the lugs  20  and  21  and by means of which the motor/pump unit  1  has been raised can now be removed. To transport the arrangement comprising motor/pump unit  1  and sound-deadening hood  9 , lifting gear provided for this purpose engages on the transportation lugs  34 .