GB2122534A

GB2122534A - Circular saw assembly

Info

Publication number: GB2122534A
Application number: GB08215270A
Authority: GB
Inventors: Chen Chi-Ming
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-05-25
Filing date: 1982-05-25
Publication date: 1984-01-18

Abstract

A plurality of circular saw blades 15 are mounted on a common hollow shaft 22 spaced apart by spacers 23. A blower 12 drives cooling medium e.g. air into the hollow shaft whence it passes centrifugally through slits 222 in the shaft and slots 233 formed in the spacers to pass across and cool the blades 15. The shaft is mounted in a bearing 11 and driven by belts 14 engaging pulley 13 all these items being cooled by medium passing through constriction 24. <IMAGE>

Description

SPECIFICATION Circular saw assembly This invention concerns a device for cooling circular saws during their operation in a sawing machine. No matter what material-lum- ber, metal, or non-metal a circular saw may cut, this newly invented device can satisfy the purpose of cooling the saw blades sufficiently by passing cooling medium around them during their operation.

According to the invention there is provided a circular saw assembly comprising a plurality of saw blades mounted on a hollow shaft, means for passing cooling medium into said shaft and means for conveying said cooling medium from within said shaft to coolingly and centrifugally pass across said blades.

Thus in use the blades are cooled by the cooling medium and the way this is passed to the blades ensures an efficient cooling action.

The shaft may be provided with a plurality of circumferential outlets through which said cooling medium passes in use, and preferably a plurality of spacers are mounted on said shaft spacedly separating said blades, and said outlets are in fluid communication with fluid passages formed in the spacers.

The cooling medium may be air, or water, or a mixture of the two.

In order that the invention may be readily understood an embodiment thereof will now be described by way of example with reference to the accompanying drawings in which Figure 1 is a longitudinal cross sectional view of an embodiment of circular saw assembly in accordance with the invention, Figure 2 is an end-on view of a saw blade, Figure 3 is an end-on view of a spacer element, and Figure 4 is a sectional view along the line IV-IV of Fig. 3.

Fig. 1 shows a cross section view of this assembly of circular saw blades 15 in a circular sawing machine, including shaft 22, bearing stand 11, work bench 10, belt 14, belt pulley 13, circular saw blades 15, saw blade spacers 23 and saw holder 16. The saw holder 16 holds the circular saw blades 15 and saw spacers 23 tightly on the shaft 22 as in a conventional circular sawing machine, so the description about it will be omitted.The main characteristic of this invention is that the shaft 22 has a hollow 221 formed in its centre part and the hollow 221 is divided into three sections of different diameters; as Fig. 1 shows, the hollow of the right hand section where the circular saws are to be held is of large diameter, the left section where the pulley 13 and the bearing stand are fixed is of medium diameter and the middle section between the two sections mentioned above is of small diameter.

At the right side of the shaft 22 is installed a blower 12, in which the air just faces towards the entrance of the hollow 221. Then while the shaft 22 is rotating and the circular saws 15 are sawing material, the cold wind produced by the blower 12 is blown-alone or together with water sent out of a water pipe 17~into the hollow 221 for the purpose of cooling and removing from the circular saws 15 the heat produced in their sawing operation.

Several slots 222 are cut at predetermined intervals on the right section of the hollow 221 where circular saws 15 and saw spacers 23 are held on the shaft 22 so as to let the cooling fluid such as air, water, be blown through the slots 222 to the saw spacers 23 and the circular saws 15 by means of centrifulal force caused by the high-speed rotation of the shaft 22.

Fig. 3 and 4 show the side and the cross section views of the saw spacer 23. At its center part is cut a shaft hole 231 through which this saw spacer 23 can be pushed and fixed around the shaft 22. There are three key ways 232 set at equal intervals on the circular edge of the shaft hole 231; these key ways 232 fit into keys set on the shaft 22, in order to lock the saw spacer 23 in the proper location. On both sides of the saw spacer 23 are cut several cooling slots 233, as the figures show, that are connected with each other. These cooling slots have exits both on the side of the shaft hole 231 and on the outside edge of the saw spacer 23, and the arrow heads show the flow direction of the cooling fluid.After the saw spacer 23 has been set on the shaft 22, the cooling slots 233 and the slots 222 on the shaft 22 form connected passages for the cooling fluid-whether gas or liquid-blown through the hollow 221 by the blower 12. When the cooling fluid can run through the slots 222 and the cooling slots 233 and finally to the circular saw blades themselves.

As Fig. 2 shows, the circular saw 15 has in the center a shaft hole 153 around which are cut three key ways 154. The shaft hole 153 and the three key ways 154 are used for fixing the circular saw on the shaft 22. The circular part shown by A is to be pressed by the saw spacer 23, and the part shown by B is the saw face 155 on whose edge are located the main saw teeth 152. As the saws 15 are to revolve at about 3360-6000 r.p.m., the heat produced by the friction of the saws and the material 2 may be extremely high. In order to avoid deformation caused by this heat, there are several crevices 156 cut in the face of the saw 15.Though these crevices 156 are to allow for metal expansion caused by heat, they are not of much use for the conventional sawing machines; when a sawing machine is furnished with this newly invented device, the crevices are not always necessary for keeping the saws 15 from thermally deforming.

Now let us go back to Fig. 1. While the circular saws 15 are sawing a material 2, revolved by the high-speed rotation of the shaft 22, the blower 12 is simultaneously blowing cool air together with some water sent out of the water pipe 17 into the hollow 221, and the cool air and the water mix and become a watery spray. If water is not used, only cool air is blown in. Once the cool air or the watery spray is blown into the hollow 221, it runs by centrifugal force into the slots 222 of the shaft 22 and the cooling slots 233 of the saw spacer 23, then across the saw faces 155, and the result is that the high heat of the saws 15 caused by the friction in their operation can be cooled down.

Instead of a blower a rotor fan can be fixed e.g. at the right hand end of the shaft 22, then the fan can rotate at the same speed as the shaft 22, driving air into the hollow 221, but it may increase the load of the shaft 22.

After the cooling medium is driven into the hollow 221 a large volume of it blows across the saw faces 155 of the saws 15 through the slots 222 of the shaft 22 and the cooling slots 233 of the saw spacer 23. However a small volume of it may be blown to the left section of the shaft 22 through the middle section of the small hollow, as Fig. 1 shows.

Then the heat produced by the friction of the belt pulley 13 and the bearing stand 11 can be cooled, and consequently can not be conducted to the right sidc namely the saws 15, the saw spacers 23, etc. Therefore, this structure gives excellent job in cooling indirectly.

At the left side of the section in the hollow 221 where the saws 15 are held is formed a tapered tip 24, useful for the cool air or the watery spray blown in to be guided evenly to the saws 15.

Claims

1. A circular saw assembly comprising a plurality of saw blades mounted on a hollow shaft, means for passing cooling medium into said shaft and means for conveying said cooling medium from within said shaft to cool in gly and centrifugally pass across said blades.

2. An assembly according to claim 1 wherein cooling medium passing means consists of a blower adapted to blow said medium into said shaft.

3. An assembly according to claim 2 wherein said blower comprises an impeller mounted on the shaft.

4. An assembly according to claim 1, 2 or 3 wherein said shaft is provided with a plurality of circumferential outlets through which said cooling medium passes in use.

5. An assembly according to claim 4 in which a plurality of spacers are mounted on said shaft spacedly separating said blades, and said outlets are in fluid communication with fluid passages formed in the spacers.

6. An assembly according to claim 5 in which said fluid passages comprise radial channels intersecting with an annular channel formed in the spacers.

7. An assembly according to any of the preceding claims in which said hollow shaft has a bearing mounted extension which is also hollow and arranged to receive said cooling medium.

8. An assembly according to claim 7 in which the interior of said hollow shaft is separated from that of said hollow extension by a constricting passage.

9. An assembly according to any of the preceding claims in which said cooling medium is air, water or an air/water mixture.

10. A circular saw assembly substantially as hereinbefore described with reference to the accompanying drawings.