JPS64317Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] This invention relates to the configuration of the cutting edge of a rotary blade of a rotary cutter suitable for cutting a roll while rewinding it in a copying machine, a facsimile machine, etc.

[Background of the idea]

As a conventional rotary cutter, there is one shown in FIGS.
The fixed blade 4 is disposed substantially parallel to the rotary blade 3, is swingably supported, and is biased toward the rotary blade 3. The rotary blade 3 has a rotating shaft 5 at both ends, and a guide 6 for positioning the fixed blade 4 with respect to the rotary blade 3 at one end. The cutting edge steel 2 is installed around the rotational center axis C of the base metal 1 at an angle with respect to the rotational center axis C, so that contact with the fixed blade 4 occurs sequentially from one end to the other end. There is. The cutting edge steel 2 is fitted into the cutting edge steel fitting groove 7 formed in the base metal 1 without a gap, and is fixed in the cutting edge steel fitting groove 7 by being bonded with an adhesive. In order to obtain the ideal cutting condition, the cutting edge steel 2 should be twisted in a spiral shape so that the cutting angle is always constant, but in the past, the cutting edge steel 2 was twisted in a straight line to reduce manufacturing costs. It was formed as follows. For this reason, there was a problem in that the cutting angle at the beginning and end of the cut became small and the cutting resistance increased. Particularly when the cutting resistance is high at the beginning of the cut, an extremely high load is generated on the drive source such as the motor, which is undesirable.

[Purpose of invention]

This invention was devised to solve these conventional problems, and the purpose is to provide a rotary blade for a rotary cutter that can suppress the increase in cutting resistance at the beginning of cutting and can be manufactured at low cost. do.

[Summary of the idea]

The rotary blade for a rotary cutter according to this invention is
The cutting edge steel is curved so that the cutting angle at the beginning of the cut is larger than the cutting angle at the middle portion, thereby suppressing an increase in cutting resistance at the beginning of the cut.

[Example of idea]

Next, a first embodiment of the rotary blade for a rotary cutter according to this invention will be described based on the drawings. In the figures, the same or equivalent parts as in the conventional example are designated by the same reference numerals.

In FIG. 3, a cutting edge steel fitting groove 7 which is wider than the cutting edge steel 2 is formed in the base metal 1 of the rotary blade 3, and a plurality of fitting grooves are formed between the cutting edge steel 2 and the side surface of the cutting edge steel fitting groove 7. Piece 8 is inserted. The fitting piece 8 is located on the rear side in the rotational direction (arrow R direction) at the cutting start end 2A of the cutting edge steel 2, on the rotational direction front side at a position closer to the middle part than the cutting start end 2A, and in the rotational direction at the cutting end 2B. The cutting edge steel 2 is arranged on the front side and on the rear side in the rotational direction at a position closer to the middle part than the cutting end part 2B, and the cutting edge steel 2 is curved so that the cutting angle at both ends 2A and 2B is larger than the middle part. There is.

As a result, the cutting resistance at both ends 2A and 2B is reduced, and the load on a drive source such as a motor is reduced. Therefore, a drive source with a smaller output than before can be used, and a simpler power transmission mechanism can be used, and manufacturing costs can be reduced. Inserted piece 8
Since the cutting edge steel 2 and the cutting edge steel fitting groove 7 can be formed straight, the manufacturing cost of the cutting edge steel 2 and the cutting edge steel fitting groove 7 is the same as before.
The gap between the cutting edge steel 2 and the cutting edge steel insertion groove 7 should be set to an optimal value depending on the thickness, material, cutting angle, etc. of the cutting edge steel 2. In a rotary blade with a length of 280 (mm) with a θ, the gap is 0.3 (mm), the fitting piece 8 near the middle part is placed at a position 30 (mm) from the ends 2A and 2B, and the There is an example in which good results were obtained with the cutting angle θ+α=1°36'.

Note that the problem of cutting resistance occurs particularly at the beginning of the cut, so as in the second embodiment shown in FIG. may be increased.

In both of the above embodiments, the fitting piece 8 or the shim is fitted into the fitting groove 7 in order to curve the cutting edge steel 2, but there is no need to limit it to this, and for example, the cutting edge steel fitting groove 7 can be It is also possible to have a structure in which the cutting edge steel is formed in a curved manner and the cutting edge steel is fitted into the fitting groove, or the fitting groove may be made slightly wide as in the above-mentioned embodiment, and the cutting edge steel itself may be formed in a curved manner. , it is also possible to eliminate the need for a fitting piece.

[Effect of idea]

As mentioned above, the rotary blade for a rotary cutter according to this invention bends the cutting edge steel in the cutting edge steel insertion groove and increases the cutting angle at the beginning of cutting, so cutting resistance at the beginning of cutting can be suppressed and the manufacturing cost can be reduced. It has an excellent effect of not increasing the amount of water. Furthermore, the groove width of the cutting edge steel insertion groove is made wider than the plate thickness of the cutting edge steel, and the structure is such that the cutting edge steel is given a predetermined bend by fitting the fitting piece, so both the cutting edge steel and the cutting edge steel insertion groove are Can be formed into a straight line shape. Therefore, the manufacturing method for imparting the bend is simple, and there is no need to process the cutting edge steel itself to impart a bend, so an increase in manufacturing costs can be suppressed. Furthermore, by changing the fitting position and number of fitting pieces, the bending angle can be easily adjusted, and an optimum cutting angle can be easily achieved.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a conventional rotary cutter, Fig. 2 is a front view showing a rotary blade in the same rotary cutter, and Fig. 3 is a front view showing a first embodiment of a rotary cutter for a rotary cutter according to this invention. , FIG. 4 is a front view showing the second embodiment. DESCRIPTION OF SYMBOLS 1... Base metal, 2... Cutting edge steel, 3... Rotating blade, 4... Fixed blade, 5... Rotating shaft, 6... Guide, 7... Cutting edge steel fitting groove, 8... Fitting piece, 2A... Cutting start end, 2B... End of cut.

Claims (1)

[Scope of utility model registration request] The base metal is rotatably supported, and the base metal has a cutting edge steel fitting groove formed around the rotational center axis, which is inclined to the rotational center axis, and the cutting edge steel is inserted and fixed into this cutting edge steel fitting groove. In the rotating shaft blade for a rotary cutter, the groove width of the cutting edge steel fitting groove is formed wider than the plate thickness of the cutting edge steel, and a plurality of fitting pieces are provided between the cutting edge steel and the side surface of the cutting edge steel fitting groove. 1. A rotary blade for a rotary cutter, characterized in that the blade edge steel is curved so that the cutting angle at the beginning of the cut is larger than the cutting angle at the intermediate portion.