Patent Publication Number: US-2004042908-A1

Title: Water pump at a portable cutting machine

Description:
TECHNICAL FIELD  
       [0001] The invention concerns a portable cutting machine, comprising a cutter unit with a rotatable cutter member in the form of a cutter disc or a saw disc, a cutter shaft for the rotation of the cutter member, a guard in the form of a protective housing for said cutter member, at least one water nozzle provided in the protective housing for the generation of one or more water jets in the space defined by the protective housing, said one or more water jets essentially laying the dust which is generated during the cutting operation and cooling the cutter member, the machine further comprising a power unit and a first power transmission between the power unit and the cutter shaft.  
       BACKGROUND OF THE INVENTION  
       [0002] A wet cutter system is known, according to which the operator carries a unit comprising a small tank and an electrical water pump in a harness on his back The unit also may stand on the ground. The system has the advantage that it can operate with a low consumption of water. However; it can not operate with petrol-powered cutting machines without access to electricity supply.  
       [0003] Combustion engine powered cutting machines has a great advantage over other types of cutting machines because they can operate without access to electricity supply.  
       BRIEF DISCLOSURE OF THE INVENTION  
       [0004] In view of the above background, the invention aims at providing an integrated portable cutting machine which combines the advantage of the portable cutting machine which is defined in the above preamble with the advantage of powering the cutting machine by means of a combustion engine. The water supply can be satisfied by conveying water to the working site in a small can or other vessel in the case the cutting machine is equipped for the supply of only a minimum of water for laying dust and for cooling the cutter member. As an alternative, water can be supplied from a possibly available water mains or from a stream, lake, well or the like, in the case a water supply of that type is available near the working site. According to said latter alternatives, the water supply to the nozzle in the protective housing may be more plentiful.  
       [0005] Further features and aspects of the invention, as well as advantages thereof, will be apparent from the appending patent claims and from the description of conceivable embodiments.  
     
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
     [0006] In the following description of some conceivable embodiments of the machine according to the invention, reference will be made to the accompanying drawings, in which  
     [0007] FIGS.  1 - 4  are side views of the machine according to some embodiments thereof  
     [0008]FIG. 5 shows how the water supply can be satisfied when a non-self-priming type of pump is employed, and  
     [0009]FIG. 6 shows a nozzle of a type which can be included in the machine. 
    
    
     DESCRIPTION OF SOME CONCEIVABLE EMBODIMENTS  
     [0010] In FIGS.  1 - 4  a cutting machine is generally designated by the reference numeral  1 . The power unit of the machine comprises a preferably petrol-powered combustion engine  2 . A cutter unit is designated  3 . Said unit comprises a rotatable cutter member  4  in the form of a cutter disc or a saw disc, which is rotated by a not shown cutter shaft, which extends through the centre of the cutter member. The cutter member is secured to the cutter shaft between inner- and outer washers of the type referred to as flange washers, which are not shown in the drawings. The cutter shaft is mounted in a pair of ball bearings in bearing housings on a tool carrier  5 , which extends forwards from a crank-case. The engine has a crank-shaft which drives a driving belt, which is designated  7  in FIG. 3, via a centrifugal clutch  6  and a rear driving wheel connected to a centrifugal clutch casing. The driving belt in turn drives a front belt pulley, which is designated  8  in FIG. 3, which belt pulley is non-rotatably connected to the cutter shaft and provided to rotate said cutter shaft and hence the cutter member  4 . The driving belt  7  is covered by a clutch casing  9  and by a front belt protection  10 .  
     [0011] The rear part of the cutter member  4  is covered by a guard in the form of a protective housing  11 . In the protective housing  11  there are provided a nozzle  12  on each side of the cutter member  4 . The nozzles  12  may be designed e.g. as will described with reference to FIG. 6. Connections to the nozzles  12 , on the outside of the housing  11 , are designated  13 . From a pump, which can be mounted at different locations in the machine according to the different embodiments which will be described in the following, a main connection conduit  14  extends. Branch conduits are designated  15  and a water supply conduit (suction conduit) to the pump is designated  16 .  
     [0012] According to the embodiment which is shown in FIG. 1, the pump is mounted on and is provided to be powered by the not shown crank-shaft of the engine  2 . The pump in this case is hidden behind the centrifugal clutch  6 .  
     [0013] In the embodiment according to FIG. 2, the pump, which is designated  20  in all the embodiments, is located inside of the clutch casing  9 , more particularly inside of a projection  21  of the clutch casing which projects downwards. The pump  20  in this case is driven by the crank-shaft, e.g. via a worm gear or via a gear wheel inside the centrifugal clutch; alternatively via a very small belt transmission between the crank shaft and a driving shaft of the pump.  
     [0014] According to the embodiment shown in FIG. 3, the pump  20  instead is located in the front belt protection  10  and is powered by the driving belt  7  via a third belt pulley  22  between the rear driving wheel and the front belt pulley  8 . The third belt pulley  22  is driven by the driving belt  20  and is in this case integrated with a belt stretcher provided for the driving belt  7 .  
     [0015] In the embodiment according to FIG. 4, the pump  20  is located in an upwards-rearwards directed projection  24  of the front driving belt casing  10 . In this case, the front belt pulley  8  is designed as a double belt pulley. Alternatively, two separate belt pulleys are provided on the cutter shaft. This second belt pulley, or the second groove of the double belt pulley, respectively, in this case drives the pump  20  via an auxiliary driving belt  25 .  
     [0016] It is also conceivable, according to an embodiment which is not illustrated in any drawing, that the pump is provided in the front belt protection  10  and is driven via a gear wheel or worm gear located between the said ball bearings on the cutter shaft. This provides a more compact solution than the embodiment which is shown in FIG. 4, where the pump is driven via an auxiliary driving belt  25 . According to still another alternative the pump is provided in the protective housing  11  inside the said inner flange washer.  
     [0017] According to still another alternative the pump is integrated in the front belt protection  10  via a driving member engaged to the front belt pulley  8  or to a central nut by means of which the belt pulley is secured to the cutter shaft such that the rotational centre of a impeller in the pump is coaxial with the rotational centre of drive shaft.  
     [0018] When a not self priming (self-sucking) pump  20  is employed, the suction conduit  16 , i.e. the water supply conduit, may be provided with a manually powered booster pump  30 , FIG. 5, in the form of a rubber bellows, for initiating the pumping. The branched conduits  15  have not been shown in this embodiment and a nozzle  12  is shown only schematically. A pair of non return valves in the connections to the rubber bellows  30  are designated  18  and are also shown at a larger scale in the same drawing.  
     [0019] Filter materials  27  are included in the nozzles  12 . In order to make it possible to employ nozzles  12  of a standard type suitable for cutting machines of various capacity, which may require different quantities of water for laying the produced dust and/or for cooling larger or smaller cutter members, the nozzles may be provided with a turnable plate  28 , FIG. 6, having a plurality of openings  29 A,  29 B,  29 C with different dimensions. By turning the plate  28 , the openings  29 A- 29 C can be registered such that they will communicate with members in the nozzle  12  for the supply of water.  
     [0020] The pump  20  preferably is a low pressure type suction pump, developing a pressure of 2-4 bar of the discharged water.