JPH04348810A - Cutter - Google Patents

Abstract

PURPOSE:To perform simple and rapid attachment and detachment of a blade without using a jig and a tool. CONSTITUTION:A tapered surface 15 is formed on the large part at a rear end of a knob bolt 8 having a tip by which a blade 6 is pressed against a blade holder 5. A spring 12 is located between the rear end part of a stopper 11 provided at a rear end part with a tapered surface 16 engaged with the tapered surface 15. Through the resilient force of the spring 12, a high friction force owing to a wedge action is exerted between the tapered surfaces 15 and 16 to prevent the drop of the blade 6 through prevention of unfastening of the knob bolt 8.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting machine such as a jigsaw or a reciprocating saw, and more specifically to a cutting machine whose blade can be easily attached and detached. In order to simplify the explanation below, the cutting machine will be described as a jigsaw.

0002

2. Description of the Related Art A conventional technique is shown in FIG. A blade 6 is attached by a set screw 31 to a blade holder 5 at the lower end of a plunger 3, which is reciprocated by a motor in a housing (not shown) via a power conversion transmission means such as a gear or a crank mechanism provided in a gear cover 2. For attaching and detaching the blade 6, a special tool such as a hexagonal wrench 30 was used.

0003

[Problems to be Solved by the Invention] As mentioned above, since a special tool such as a hex wrench 30 is used to attach and detach the blade 6, the blade 6 cannot be replaced if the tool is lost. There was a problem. Further, unless the set screw 31 is tightened considerably, the set screw 31 will loosen due to vibration during cutting, and in the worst case, the blade 6 will fall off.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to enable the blade to be attached and detached easily and quickly without using special jigs, and to prevent the blade from falling off due to vibration during cutting. It is to prevent it.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the cutting machine of the present invention has a tapered surface that engages with a tapered surface provided at the rear end of the knob bolt whose tip presses the blade against the blade holder. The blade holder is characterized by a stopper having a rear end thereof, and a spring provided between the rear end of the stopper and the blade holder. Further, the stopper is prevented from rotating by providing the stopper with a planar engaging portion that engages with the planar engaging portion of the blade holder.

[0006]

[Operation] In the cutting machine configured as described above, when the blade is pressed against the blade holder by the knob bolt, the stopper is pushed toward the blade holder by the action of both tapered surfaces, the spring force of the spring increases, and both tapered surfaces In other words, a large frictional force is applied to the fitting surface between the knob bolt and the stopper due to the wedge effect.
There is no longer any risk of the blade falling off due to vibration loosening the knob bolt.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. 1 to 3 showing examples. FIG. 1 shows the main parts of the cutting machine of the present invention. A plunger 3 is reciprocated in the vertical direction in FIG. 1 by a motor in a housing 1 forming a main body frame via a power conversion transmission means such as a gear and a crank mechanism housed in a gear cover 2 forming a part of the main body frame. Being exercised. A blade holder 5 integrally formed at the lower end of the plunger 3
The blade 6 is inserted into the blade holder 5, and the blade 6 is attached into the blade holder 5 by a knob bolt 8, which will be described later. Note that 4 is a metal that supports the plunger 3 in a reciprocating manner, and 7 is a base.

FIGS. 2 and 3 show details of the blade attachment section. A set piece 13 on which the blade 6 is pressed by the knob bolt 8 is attached in the blade holder 5 by a pin 17. The blade 6 side of the set piece 13 is formed into a substantially planar shape, and claws 14 that serve as guides when the blade 6 is attached are provided on both sides thereof. The blade 6 is provided at the center of the knob bolt 8 and has a threaded portion 9 that is screwed into the blade holder 5.
is pressed against the set piece 13 by the tip. A large-diameter gripping portion is provided at the rear end of the knob bolt 8, and a tapered surface 15 is provided at the tip of the gripping portion. A blade holder 5 and a stopper 11 having an engaging portion 19 that engages with a planar engaging portion 18 of the blade holder 5 at the tip and a tapered surface 16 facing the tapered surface 15 of the knob bolt 8 at the rear end. A spring 12 is provided between them.

When the knob bolt 8 is tightened, the tip of the knob bolt 8 presses the blade 6 against the set piece 13, and the blade 6 is securely installed and fixed in the blade holder 5. At the same time, the stopper 11 is engaged with the tapered surfaces 15 and 16, so that the blade 6 is firmly attached and fixed to the set piece 13. Since it is pushed toward the holder 5 side, the spring 12 is compressed and its spring force increases. Therefore, a large frictional force due to a wedge action is exerted between the tapered surface 15 and the tapered surface 16, that is, between the knob bolt 8 and the stopper 11, so that the knob bolt 8 is prevented from loosening due to vibrations during cutting. As a result, the blade 6 will not fall off from the blade holder 5. In addition, to remove the blade 6, it is sufficient to hold the grip part of the knob bolt 8 and turn it in the opposite direction.

0010

As described above, according to the present invention, the blade can be easily and quickly attached and detached without using special jigs and tools, thereby improving work efficiency. Further, there is an effect that there is no fear that the blade will fall off due to vibration during cutting.

[Brief explanation of drawings]

FIG. 1 is a side view of a cutting machine showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing the blade attachment part of FIG. 1;

FIG. 3 is a bottom view of FIG. 2.

FIG. 4 is a perspective view showing an example of a conventional jigsaw.

[Explanation of symbols]

1 is the housing, 2 is the gear cover, 3 is the plunger, 5
is the blade holder, 6 is the blade, 8 is the knob bolt, 1
1 is a stopper, 12 is a spring, 13 is a set piece, 15 and 16 are tapered surfaces, and 18 and 19 are engagement surfaces.

Claims (2)

[Claims] 1. A cutting machine in which a blade is attached via a blade holder to the tip of a plunger that is reciprocated by a motor, and cuts during the reciprocating movement of the blade, comprising:
a knob bolt having a threaded portion screwed into the blade holder, a large-diameter gripping portion at the rear end, and a tapered surface provided inside the gripping portion, and pressing the blade against the blade holder with the tip of the threaded portion; A stopper having a tapered surface that engages with the tapered surface of the knob bolt and whose tip extends to the blade holder, and a spring provided between the rear end of the stopper and the blade holder. cutting machine. 2. The cutting machine according to claim 1, wherein the tip of the stopper is a flat engaging part that engages with a flat engaging part of the blade holder.