CHAIN SAW GUIDE BAR WITH REPLACEABLE TUBES

Abstract: Guide bar for chain saws with means for marking of sawn surfaces with colour stripes, comprising two side plates (11), one center plate (31) and a number of lining tubes with their front portions (51) removably inserted in a central longitudinal slot (41) in the center plate and provided with nozzles (52, 53) for spraying liquid paint through spray holes (21, 22) in a side plate, and with their rear parts laterally bent away from the slot and provided with cup-shaped end fittings (54) pressed into holes (20) in a side plate when installed to restrict the longitudinal mobility of the tube. The guide bar is reversible by turning the tubes to lift end fittings (54) out of the holes (20), withdrawing the tubes, turning the guide bar around its longitudinal axis and reinserting the tubes in a new position.

Description: CHAIN SAW GUIDE BAR WITH REPLACEABLE TUBES Background When trees are felled and cut to logs of different lengths for saw timber or pulpwood, there is a need to indicate the proposed classification by marking each log in a clearly visible manner to facilitate sorting. The classification is done while the tree is being cut, taking into account the tree species, the diameter, the length and the existence of knots or damage, as well as the need for different types of logs. The classification may depend on operator decisions as well as automatic measurements in a tree harvester machine. According to the patent SE 469 974 the marking can be done in a tree harvester with a vehicle-mounted chain saw by providing the chain saw guide bar with internal channels through which paint or other marking fluid can be sprayed on the surface cut by the saw chain. By letting each channel have just one spray nozzle opening through the guide bar surface, the opening of each channel offset lengthwise, it is possible to mark the cut wood surface with non-overlapping colour streaks if the marking fluid is pressurized. If the fluid of a channel is not pressurized, the corresponding streak will be missing. In this way, two channels will permit four classifications, and three channels will permit eight, presuming each channel has a different marking colour. If trees of greatly differing diameters are to be handled, it may also be an advantage to let each channel have two openings, located in groups to make two similar sets of colour streaks, to make certain that at least one set traverses the cut surface. Pressurizing a marking fluid channel or not is realized by having pressurized fluid storage vessels with openable valves, or by having non-pressurized fluid storage vessels with metering pumps. It is also possible to have a common transfer medium, with marking pigment added close to the chain saw guide bar. Each marking fluid channel of the guide bar is connected to a channel extending from the vehicle through the guide bar holder, including swivels or flexible elements to allow marking fluid supply while the guide bar with the chain is cutting through the tree trunk. Previously known guide bars for use in marking have been made with spray nozzles on one side only, and have thus not been reversible when one guide bar edge has been worn. The present invention concerns a guide bar which can be reversed by withdrawing and relocating lining tubes in a common wider guide bar slot. This allows a greater number of independent channels, or channels of greater cross-section than if the channels are permanently located, while still avoiding mixing of the marking fluids. Description A chain saw guide bar according to the invention is described with reference to the figures, where figure 1 shows an exterior view of a guide bar, figure 2 the center plate of a guide bar, figure 3 a lining tube withdrawn from a guide bar and figure 4 a section through a guide bar. The guide bar is of laminated type, comprising two side plates (11) joined to a center plate (31) by welding or brazing. As shown in the exterior view, figure 1, each side plate has a nose end (12), and a rear end with a bolt slot (13) for the clamping bolts holding the guide bar. The front of the bolt slot has a widening (14) towards one side. Adjacent to the bolt slot are two through holes (15) for adjustment lugs to locate the guide bar in the longitudinal direction, and an oil supply hole (16) to receive and convey lubricating oil to the saw chain. Opposite to the widening (14) there are holes (17,18), and through the widening the corresponding holes (19,20) of the other side plate are visible. In the middle region of the guide bar there is one or more groups of spray holes (21,22), the spray holes in each group longitudinally separated. The center plate (31) shown in figure 2 is generally narrower than the side plates, to create a chain groove around the guide bar for guiding the saw chain when a center plate has been joined with two side plates. There is a bolt slot (33) corresponding to the slot (13) in the side plates, and a large symmetric widening (34) corresponding to the widening (14) in the side plate, but extending on both sides of the slot. The slot has a forward extension (41) reaching somewhat further towards the front than the spray hole groups (21,22). There are two through holes (35) for adjustment lugs matching the holes (15) of the side plates. At the edge there are two notches (36) forming an oil channel from the supply holes (16) to the bottom of the chain groove. Figure 3 shows a lining tube separated from the guide bar. The tube comprises a thin- walled tube of soft metal such as brass, and has a straight front section (51) with nozzle holes (52,53) with the same distance as between the spray hole groups (21,22) in the side plate. If there is only one spray hole group, the tube has only one nozzle hole. The front end (56) of the tube is sealed by compression or by soldering. The rear part (57) of the tube is bent slightly to one side at a bend (55). At least the straight section (51) between the front end (56) and the bend (55) must have an exterior thickness not greater than the thickness of the center plate (31). At the extreme rear, the tube is attached to a fitting (54) shaped as a cylindrical cup with a diameter larger than that of the tube. Since in some operations it would be sufficient to use only one of the groups of spray holes (21,22) it may be advantageous to deliver lining tubes without nozzle holes or with plugged holes, and let the user drill out the nozzle holes needed. When assembled and ready for use, a number of lining tubes equal to the number of spray holes in each group (21,22) is inserted in the forward extension slot (41), the width of which is chosen so that the tubes fit snugly. The nozzle holes (51,52) of the tubes will then be located inside corresponding spray holes (21,22), which are larger than the nozzle holes so that they support the tubes but do not interfere with the paint spray. As shown in figure 3, which is a section through a guide bar at the rear end of the lining tubes, each tube fitting (54) has one end located in a round hole (20) in one side plate to secure the tube in a longitudinal direction, and the other end is located in the widening (14) of the other side plate. The intermediate part of the fitting and the adjoining rear parts (43,44,45) of the tubes are located in the large widening (34) of the center plate. According to the invention, the lining tubes can be easily removed and replaced in the guide bar when needed. This is done for many different reasons. If a marking fluid channel has been obstructed by dirt particles or dried paint, the lining tubes can be removed and replaced by new or cleaned tubes. If other marking colours are to be used for a certain operation, the old lining tubes should be replaced by new to avoid mixing of old and new marking fluid. If the guide bar has been unsymmetrically worn, it should be reversed by turning around a longitudinal axis and the tubes replaced in the new position. If a guide bar has been deformed and needs straightening, this is best done while the tubes are removed. When a lining tube is to be removed from the guide bar, the tube fitting is pushed from the round hole (20). The straight front section (51) of the tube then rotates in the slot extension (41) while the rear part of the tube (57) is raised within the widenings (14,34). The tube can the be withdrawn through the slot (13,33). Tubes can afterwards be inserted correpondingly into the slot and rotated to engage the fitting (54) in a round hole (20). The fitting (54) is cup-shaped with one end open to receive marking fluid from the guide bar holder. The end surface should preferably be wide enough to form a leak-proof seal with a soft sealing element recessed in the guide bar holder. If all tube fittings are on the same side of the guide bar center line, as is usually the case with two tubes, all open ends penetrate round holes and the sealing element may then form a seal wholly or partly with the side plate surface around the hole. If it is desired to make the guidebar slightly slideable relative to the holder by moving the lugs engaging the through holes (15) in order to adjust the chain tension, one way to secure a good seal is to make the fitting (54) with a sliding fit in the hole (20) of the side plate and with a centering element with conical or cylindrical surfaces to keep it aligned with the seal element of the guide bar holder. When the chain saw is in position to fell a tree, the open cup end should preferably be upward, and the nozzle holes downward.

Claims: CLAIMS 1. Guide bar for chain saws, comprising two side plates (11), one center plate (31), said plates having slots and holes for attaching the guide bar to a guide bar holder of a chain saw machine, and a number of lining tubes the front portion (51) of which is removably inserted in a longitudinally extended slot in the center plate, said lining tubes conveying marking fluid from a cup-shaped fitting (54) at the rear end of the tube in contact with the bar holder to spray holes (21,22) in a side plate (11), characterized by the guide bar being reversible around its longitudinal axis and the tubes being removable and shiftable from one position before reversing to another position after reversing, said position determined by a hole (20) in a side plate into which the end fitting (54) is pressed. 2. Guide bar according to claim 1, characterized by the end fitting (54) being so tightly seated in the hole (20) that the tube can not move relative to the guide bar. 3. Guide bar according to claim 1, characterized by the end fitting (54) having a limited mobility relative to the guide bar, but being fixed to the guide bar holder by a centering element. 4. Guide bar according to claim 1, characterized by the tube having a straight front part (51) and a bend (55) and by a rear tube part (57) between the bend and the fitting (54) being offset to one side and located in a lateral widening (14,34) of the extended slot (41). 5. Guide bar according to claim 4, characterized by straight front sections (51) of two or more tubes being located side by side in a single slot (41) along the center line of the guide bar. 6. Guide bar according to claim 4, characterized by each tube being rotatable a limited angle around its straight part (51) to raise the rear part (57) out of the widening (14,34) and the end fitting (54) out of the hole (20), after which the tube can be withdrawn from the slot. 7. Guide bar according to claim 5, characterized by the spray holes (21,22) being located in groups, each group comprising as many holes as the number of tubes. 8. Guide bar according to any of the previous claims, characterized by the tubes having nozzle holes (52,53) smaller than the spray holes (21,22).

Inventors: LEINI ARVO, LEINI, ARVO
Applicants: SANDVIK AB, SANDVIK AKTIEBOLAG
Application year: 1997
Main classification: B27B17
IPC codes: A01G3, B23D57, B27B17