JPH0342962Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is a drag-type interchangeable (or replaceable blade) saw;
That is, the present invention relates to an improvement of a device in which a saw blade is detachably and replaceably connected to a handle.

[Prior Art] A so-called replacement saw in which the saw blade is removably connected to the handle without using a connecting fitting such as a bolt that must be removed each time is disclosed in, for example, Japanese Utility Model Application No. 12592/1983. This is being proposed in the official gazette.

This conventional saw has a longitudinally long support piece pivoted in a groove on the back edge of the handle whose tip is split into two at approximately the midpoint, and a latch protrusion provided at the tip of this support piece. By providing recesses vertically facing each other between the part and the peg provided below the protrusion, the head formed at the base end of the saw blade can be inserted from the front in the extending direction of the handle. The saw blade is connected to the handle by engaging the peg in the downward recess and the latch protrusion in the upward recess, and then pushing the base of the support piece into the handle to remove the saw blade from the handle. It is designed to be removable.

[Problem that the invention attempts to solve]

By the way, when the above-mentioned conventional (Japanese-style) saw is used, when the handle is pulled toward the front, the force acts on the saw blade in the direction of pulling it out from the handle, and part of this force is applied to the tip of the support piece. The engaging portion of the latching protrusion and the recessed portion of one side are engaged with each other. Therefore, if the engagement between the latch protrusion and the recess is insufficient, or if they easily come off or slip, the saw blade and handle may shake during use, which is an inconvenience.
There is a danger.

The present invention was developed in view of the above circumstances, and it not only ensures the engagement between the saw blade and the handle, but also strengthens the engagement force between the two when a force is applied to the saw blade in the pulling direction against the handle. The purpose is to make it easier to understand.

[Means for solving problems]

In the connecting device of the present invention, a slit is formed at the tip of the handle to divide it into left and right halves, and a shaft rod is fixedly inserted into the slit in a penetrating manner. In the cavity, a latch having an engaging part bent downward at the tip and an actuating part pointing upward and protruding outside the handle at the rear end is pivoted so as to be able to swing up and down by a fulcrum pin in the middle part. , and a spring is provided below the operating portion of the latch to bias the engaging portion downward; In a replacement saw, the saw blade is supported so as to be taken out in the forward direction, and the saw blade is engaged with and disengaged from a recessed portion near the base of the saw blade, and the engaging portion of the latch and the recessed portion of the saw blade are each formed into a wedge shape. ,
Furthermore, a space is provided between the upper and lower abutting parts when these two are engaged, and the point of application of force between the two is located above the horizontal line passing through the center of the fulcrum pin of the latch. That's what I do.

[Effect]

In the present invention, when connecting the saw blade to the handle, the saw blade is bent at an appropriate angle relative to the handle and inserted into the slit, thereby inserting the shaft rod into the kerf at the base of the saw blade. When the saw blade is rotated forward in the extending direction of the handle about the shaft, the tip of the latch, which is biased downward by a spring, engages in a recess provided on the back edge of the base of the saw blade. The parts can be brought into engagement and ready for use. To remove the saw blade from the handle, first push the operating part of the latch into the handle to disengage the engaging part of the latch from the recess, and then rotate the saw blade in the opposite direction to the cut groove. All you have to do is pull it away from the handle along the direction in which it is formed.

According to the present invention, even if the front and rear contact surfaces of the engaging part of the latch and the recessed part of the saw blade are worn out in the above-mentioned state of use, both form a wedge shape, and there is a gap between the upper and lower contact parts. , so that the engaging part gradually bites in, and furthermore, the point of force application in the engaging part and the recess is located above the horizontal line passing through the center of the intermediate fulcrum pin of the latch. Therefore, the component of the force generated when the saw is pulled toward the front of the handle acts on the latch in a direction that causes the engaging portion at the tip to plunge into the recess.
As a result, the connection between the saw blade and handle can be made as strong as possible.

〔Example〕

Next, the present invention will be described with reference to the embodiments shown in FIGS. 1 to 3. Reference numeral 1 denotes a replaceable saw handle having a saw blade 2 removably connected to the tip in an extending direction, and the back edge 1 of the handle. A slit 3 in the vertical direction is formed in the tip portion except for ``, and a vertical slit 3 is formed to divide it into left and right halves, and a shaft rod 4 having a circular cross section is fixedly fixed in a penetrating manner within the slit so as to cross the width direction. Reference numeral 5 denotes a latch which is interposed in a hollow 6 formed in the upper part of the slit 3 in the handle 1 so as to communicate with the rear by pivoting the intermediate part thereof with a fulcrum pin 7 parallel to the shaft rod 4. The latch has a wedge-shaped engagement part 5a at its tip facing downward so as to face the shaft 4, and an upwardly facing actuating part 5b protruding from the handle 1 at the rear. The engaging portion 5a is biased in the direction of lowering by a spring 8 provided below. The saw blade 2 has teeth 9 formed on one side edge thereof, and the rear end of the saw blade inserted into the slit 3 has teeth 9 formed thereon.
The width is the same as the diameter of the shaft 4, and the saw blade is bent from the used state in which it projects forward in the direction of extension of the handle 1 to the bent state in which it is rotated downward at an appropriate angle around the shaft 1. In order to be able to be inserted into and removed from the time axis rod 4, it is either approximately perpendicular to the side edge of the saw blade 2 where the teeth 9 are formed (Fig. 1) or inclined at a slight angle either forward or backward from the direction. A cut groove 10 in which the shaft rod 4 intervenes in the direction (FIG. 3 shows the rear) is formed so as to communicate with the outside of the side edge. Further, the upper part of this cut groove is provided with an entrance so that the engaging part 5a of the latch can be engaged from above, and the front and rear edges A and B of the engaging part can be brought into close contact with each other when engaged. The upper part of the wall is expanded into a wedge shape, and a recess 11 is provided below the engaging part so that a gap S can be provided, and when the engaging part 5a is engaged with the recess 11, The intermediate point of action P at the contact part of the rear edge is
It is determined to be located above the horizontal line passing through the center of the fulcrum pin 7 of the latch 5 mentioned above.

With the above configuration, when connecting the saw blade 2 to the handle 1, the shaft rod 4 is inserted into the kerf 10 with the saw blade 2 and handle bent as shown in FIG. If you rotate either the saw blade or the handle around , and position them both in the direction of the extension line as shown in Figure 1,
The engaging part 5a of the latch 5 fits into the recess 11 provided on the rear part of the saw blade 2, so that both the saw blade 2 and the handle 1 are connected to the shaft 4 and the engaging part 5a in two places, upper and lower. They are connected.

At the time of this connection, the intermediate point of action P of the rear edge contact portion between the engaging portion 5a of the latch and the recessed portion 11 of the saw blade is located above the horizontal line passing through the center of the pivot fulcrum pin 7 of the latch 5. As a result, the component of the force generated at the point of application P when the saw is dragged acts in the direction of press-fitting the engaging portion 5a into the recess 11, thereby making the engagement between the two even stronger. be.

To explain this with reference to Fig. 4, Fig. 4A shows a case in which point P is below the - line, contrary to the previous example, and one component f of the force F generated at point P is applied to the latch 5.
In addition, in B, the force F generated at point P acts in the direction of the - line.For this reason, in A, the latch 5 is likely to come off from the recess 11, and in B, it is easy to remove the latch 5 from the recess 11, and in B, the force F generated at point P acts in the direction of the - line. They are the same, and the engagement between the two is not strong. On the other hand, Fig. C is the same as the embodiment described above, in which one component f of the force F generated at point P acts on the latch 5 downward in a counterclockwise direction, thereby causing the engagement portion and the recess to engage. can be made powerful.

Regarding the direction of the force F, when using this type of drag-type saw, the teeth 9 are pressed downward and the saw is pulled toward the handle 1 in front (towards the right in Figure 1). Therefore, a force is generated in the saw blade 2 that causes it to rotate clockwise around the shaft rod 4, and a force directed toward the left as it attempts to escape from the handle. However, during the cutting operation, the latter force is overwhelmingly larger than the former, so that a leftward force F is generated at point P. Therefore, it is preferable to leave a slight gap between the upper rear surface of the latch 5 and the inner surface of the upper wall 1' of the handle 1 in the connected state as shown in FIG. 1. It is.

Also, when removing the saw blade 2 from the handle 1, the operating part 5
The saw blade 2 can be rotated in the opposite direction to the above while the saw blade 2 is pressed against the spring 8 and pulled out in the direction in which the kerf 10 is formed.

[Effect of idea]

According to the present invention, not only can the saw blade be attached to and removed from the handle smoothly and quickly, but also the component of force generated due to the relationship between the recessed part of the saw blade and the latch engaging part when the saw is dragged during use is reduced. , will act in the direction of strengthening the engagement between the two, and since the recess and the engaging portion are wedge-shaped and have a biting relationship, there will be no looseness between the two even during long-term use. This allows the saw to be used safely and powerfully.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional side view of the present invention, Fig. 2 is a partial side view showing the saw blade attached and removed, Fig. 3 is a side view showing another embodiment of the saw blade, Fig. 4 A, B, C is a schematic side view for explaining the relationship between the saw blade and the latch. 1 is the handle, 2 is the saw blade, 3 is the slit, 4 is the shaft,
5 is a latch, 5a is an engaging portion, 5b is an operating portion, 6 is a cavity, 7 is a pivot pin, 8 is a spring, 9 is a tooth, 10 is a kerf, and 11 is a recess.

Claims (1)

[Scope of utility model registration request] A slit is formed at the tip of the handle to divide it into left and right halves, and a shaft rod is inserted into the slit in a penetrating manner. A latch having an engaging portion bent downward and an actuating portion facing upward and protruding out of the handle at the rear end is pivotally mounted to be vertically swingable by a fulcrum pin in the intermediate portion, and the actuating portion of the latch is A spring is provided below the edge to urge the engaging portion downward, and the engaging portion of the latch is
In the replacement saw, the latch is engaged with and disengaged from a recess on the back edge near the base of the saw blade, which is supported so that it can be taken out forward in the extending direction of the handle by intervening a cut groove in the shaft rod. The joint portion and the recessed portion of the saw blade are each formed into a wedge shape, and a space is provided between the upper and lower contact portions when these two are engaged, and the point of force application on the two is set at the fulcrum pin of the latch. A saw blade connecting device for a replacement saw, characterized in that the saw blade connecting device is positioned above a horizontal line passing through the center.