Stone working – Sawing – Endless
Patent
1989-03-31
1991-01-01
Phan, Hien H.
Stone working
Sawing
Endless
301234, 30384, 83574, B28D 108
Patent
active
049811290
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a chain saw for sawing in very hard and difficultly worked material such as concrete, the saw including a drive motor unit, a saw chain bar connected to the unit and an endless saw chain arranged to circulate round a drive sprocket in the drive motor unit and a nose sprocket which is rotatably mounted at the free nose end of the bar, the saw chain including cutting links provided with cutting elements, these links being held together with the aid of connecting links co-acting with the teeth on the drive and nose sprockets.
TECHNICAL BACKGROUND
Motor driven chain saws are often used in the building industry for making holes in walls and the like, which are made from timber or other easily worked materials. When it is a question of making holes in hard materials, such as concrete, it has been found that utilizing chain saws with success has not been possible. The reason for this seems to be the very difficult working conditions that are met with, inter alia due to the formation of dust, slurry, etc. which gives heavy wear, blockages and other problems which make great demands on the equipment utilized.
Instead, so-called core drills are often used, i.e. a large number of holes are drilled along the defining line of the opening it is desired to achieve, which is obviously laborious and expensive.
Hand-held so-called diamond saws are also used, these being hydraulically driven and water cooled, which requires separate extensive auxiliary equipment. Such a saw has an annular saw blade with an outer edge provided with cutting elements and which is mounted in a drive means at one side so that the saw blade can be caused to circulate, that is, to rotate about its axis. Work with this type of saw is extremely trying and the possible saw blade diameters and saw depths are heavily limited.
OBJECT OF THE INVENTION
The object of the present invention is to provide a chain saw enabling effective sawing in hard materials such as concrete and other difficultly worked materials, while at the same time keeping the saw simple, reliable, light and versatile to work with.
SUMMARY OF INVENTION
The above mentioned object is achieved by a chain saw having the distinguishing features disclosed in the accompanying claims.
The inventive chain saw is thus distinguished by it having a nose sprocket arranged between two cheek plates at the nose of the chain bar, the sprocket being rotatably mounted with the aid of a bearing arranged between the cheek plates. The inner spacing between the plates corresponds to the thickness of the nose sprocket, i.e. the spacing is somewhat greater so that solely mounting gaps are formed therebetween. The circumferential area of the nose sprocket with associated teeth at the nose or front end of the bar is outside the cheek plates for at least half the circumference of the nose sprocket, so that the saw chain passing over the sprocket is entirely free from the plates and the rest of the chain bar. In other words, hers the saw chain is in no way guided in or by the cheek plates, and only co-acts with the tooth area of the nose sprocket. In addition, there are means for supplying pressurized lubricant via the bar to the above-mentioned mounting. The lubricant pressure and the gaps which are thus to be found between the side surfaces of the nose sprocket and the inner surfaces of the cheek plates are such that in operation lubricant can pass out through the gaps. In this way dust, slurry etc. caused by sawing is prevented from penetrating into the gaps simultaneously as the passing saw chain is lubricated by the outwardly forced lubricant. Means are also arranged for supplying flushing and cooling medium via the bar for flushing the saw chain and co-acting parts of the nose sprocket clean and simultaneously providing required cooling and removal of material cut by the saw. This flushing and cooling medium, which is preferably water, is arranged for ejection against the saw chain and the nose sprocket at the place where the saw chain meshes with the
REFERENCES:
patent: 3044506 (1962-07-01), Oehrli
patent: 3545422 (1970-12-01), McNulty
patent: 4361960 (1982-12-01), Halverson
patent: 4382334 (1983-05-01), Reynolds
Andersson Sture
Osterman Bror E.
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