Patent Publication Number: US-6219921-B1

Title: Chain saw guide bar with cleaning means

Description:
BACKGROUND 
     Chain saw guide bars, especially for mounting on tree harvest vehicles, are often provided with internal channels for spraying the sawn surface with liquids such as fungicides, where the channels are made with several small nozzles. The liquid may sometimes contain particles, including dirt or crystals settled during interruptions of the work, or when a guide bar has been dismounted for servicing. The nozzles are so small that they may be clogged by such particles, and there is a need for cleaning the channels, which is very difficult with prior guide bar designs. 
     According to the invention, the channels can be cleaned by compressed air as part of servicing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURE 
     FIG. 1 shows an exterior view of the guide bar according to the present invention. 
    
    
     DESCRIPTION 
     A guide bar according to the invention is described with reference to FIG. 1, showing an exterior view. The guide bar has a clamping end ( 11 ) with supply holes ( 12 ) where liquid is supplied from the power unit. The liquid travels through one or more channels ( 13 ) in the guide bar to a multitude of nozzles ( 14 ) which may be located at the main channel or at branches to it. The nozzles have basically the same small size and cannot be used to clean the channels by compressed air, since they will not let in enough air to clean the wider channels, and since most of the air would escape through neighbouring nozzles instead of following the channels ( 13 ) to the supply holes ( 12 ). 
     According to the invention each channel is extended past the outermost nozzle or branch to an end portion ( 15 ). This allows particles to collect in the end portion without forming tough deposits or clogging nozzles. The end portion ( 15 ) is terminated with a large closeable cleaning hole ( 16 ), which is closed by a plug when in use. The cleaning hole are the plug are preferably threaded. When the guide bar is to be cleaned, the plug is removed and the cleaning hole connected to a compressed air supply, which allows particles and liquid remains to be blown along the channel ( 13 ) and out through the supply hole ( 12 ). Alternatively, the compressed air supply can be connected to the supply hole and the particles be blown out through the cleaning hole ( 16 ). For dried liquid remains, water or other solvents can be used instead of compressed air. 
     When the channel has been cleaned, the plug is reattached to the cleaning hole ( 16 ) and the guide bar can be used again.