JP2003048119A - Reciprocating cutting tool having blade fitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reciprocating cutting tool having a blade fitting device capable of surely stopping a blade in a single operation. SOLUTION: A rotatable blade guide 15 is fitted to a rod member 12 having a slot 12a for passing the blade in the state of being energized by a torsion spring 18. A through hole 15b for allowing a stopping projection of the blade 5 to pass through it is formed in the blade guide 15, and a stopping projection is formed to be locked on the hole edge part depending on the rotating angle position of the blade guide 15. A push pin 13 movable in the direction right- angled to the axis is mounted on the rod member 12, and a cam 16 brought into sliding contact with the push pin 13 is mounted on the blade guide 15. The cam 16 is provided with a cam face 16a for pushing forward the push pin 13 and a cam face 16b for not pushing it which are continuously disposed. The projecting part 15d of the blade guide 15 is engaged with a hook part 30c of an operating member 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating cutting tool such as a jigsaw, and more particularly to an improvement of a blade mounting device for mounting a blade on a reciprocating drive shaft.

[0002]

2. Description of the Related Art In this type of tool, a blade (cutting tool) is used.
Since the blades are exchanged relatively frequently, the operability when attaching and detaching the blade is important. For this reason, various techniques have conventionally been developed to improve the operability when the blade is attached and detached (for example, US Pat. No. 5,946,810, JP-A-6-
304902). In these conventional techniques, a blade attachment device is attached to the lower end of the drive shaft, and the blade attachment device clamps the blade proximal end to attach the blade to the drive shaft. Some of the blade attaching devices include a retaining mechanism for preventing the blade from falling off the blade attaching device. The conventional blade retaining mechanism is performed by a retaining support member rotatably mounted on a rod member (fixed to the lower end of the drive shaft). Specifically, the rod member having an insertion portion into which the blade base end portion is inserted is equipped with a retaining support member that is rotatable about an axis. The stopper support member is formed with a penetrating portion through which the stopper projection formed on the side edge of the blade base end portion can penetrate. In such a configuration, when the retaining support member is positioned at the blade attachment / detachment position, the retaining protrusion can pass through the penetrating portion, and the blade base end portion is inserted into the insertion portion of the rod member. After the retaining projection passes through the penetrating portion, the retaining support member rotates around the rod by a predetermined angle to lock the retaining projection and prevent the blade from falling off.

[0003]

In the above blade retaining mechanism, the retaining support member rotates the rod around the rod by a predetermined angle to prevent the blade from retaining. That is, in order to reliably prevent the blade from coming off, the removal-preventing support member must rotate from the blade attaching / detaching position by a predetermined angle. However, in the conventional device, when the plate thickness of the blade attached to the blade attaching device is large, the retaining support member may not be able to rotate by a sufficient angle, which may result in insufficient retaining of the blade. . Therefore, an object of the present invention is to provide a reciprocating cutting tool provided with a blade mounting device capable of reliably preventing the blade from coming off.

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems, the invention according to claim 1 provides a blade mounting device for mounting a blade having a retaining projection on a side edge of a base end portion to a reciprocating drive shaft. A reciprocating cutting tool comprising: a blade mounting device, which is fixed to a lower end portion of a drive shaft, and has a rod having an insertion portion formed so that a blade base end portion can be inserted upward along an axis of the drive shaft. Member, a pusher member that is attached to the rod member, and is movable in a direction in which it comes into contact with or separates from the side surface of the blade base end portion that is inserted into the insertion portion, and the rod member that rotates about the axis. And a retaining support member which is mounted so that it can pass through the retaining projection and which is formed so as to be locked at a position rotated around the axis with respect to the retaining projection that has passed through the penetration portion. Prepare The retaining support member is provided with a cam that pushes the pusher member in the direction perpendicular to the axis in response to the rotation operation of the retaining support member. The pusher member is not pushed during the rotation operation from the blade attachment / detachment position that can be inserted into the blade to the push start position that is rotated by a predetermined angle, and the pusher member is further rotated from the push start position to push the pusher member. Push forward. In the reciprocating cutting tool described above, when the retaining support member is positioned at the blade attaching / detaching position, the retaining protrusion passes through the penetrating portion of the retaining support member, and the blade base end portion is inserted into the inserting portion of the rod member. . When the retaining support member is rotated around the axis from the blade attachment / detachment position, the retaining protrusion locks the retaining protrusion that has passed through the penetrating portion to support the blade from falling. At the same time, when the retaining support member is rotated, the cam pushes the pusher member in the direction perpendicular to the axis, and the pusher member presses the blade to hold the blade. Here, the cam provided on the removal-prevention support member is set within a so-called play rotation angle range in which the push-out member is not pushed in the direction perpendicular to the axis line from the blade attachment / detachment position to the pushing start position. Therefore, while the retaining support member is rotated to the pushing start position, the pusher member does not contact the side surface of the blade inserted into the insertion portion, and the rotation is not limited. Therefore, regardless of the thickness of the blade inserted into the insertion portion, the retaining support member can be reliably rotated to the pushing start position, so that the blade can be reliably retained.

In the above reciprocating cutting tool, when the retaining support member is further rotated from the pushing start position, the common normal line at the contact point between the cam and the pusher member and the contact center to the rotation center of the cam. The angle between the line segment and the line segment is 12 ° -16
It is preferably in the range of °. Here, in other words, the above angle is an angle formed by a common tangent line at the contact point and a straight line orthogonal to a line segment from the contact point to the rotation center of the cam. This angle will be referred to herein as the "friction angle". When the friction angle increases, the force for pushing the pusher member (the force for clamping the blade) decreases, and the difficulty of biting between the pusher member and the cam surface tends to increase. Therefore, by setting the cam so that the friction angle is within the range of 12 ° to 16 °, while the force for clamping the blade is sufficient within the angular range in which the retaining support member can rotate from the pushing start position, It is possible to create a situation in which the pusher member and the cam surface do not bite each other.

In the above reciprocating cutting tool, it is preferable that a taper surface for guiding the blade to a regular position is formed at a part of the hole edge portion of the penetration portion of the retaining support member. The pusher member and the blade base end portion do not come into contact with each other while the retaining support member is rotated from the blade attachment / detachment position to the pushing start position, so that the blade base end portion can correct its position in the insertion portion. Becomes Therefore, in the reciprocating cutting tool described above, the position of the blade base end portion is corrected by making a part of the hole edge portion of the penetration portion of the retaining support member a taper surface, and the smooth rotation operation of the retaining support member is possible. Becomes

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The reciprocating cutting tool described in each of the above claims can be suitably implemented in the following modes. (Mode 1) A seal member is provided between the retaining support member and the rod to seal a gap between them. The sealing member is provided with a locking piece, and the rod is formed with a groove into which the locking piece fits. According to such a configuration, since the engagement piece of the seal member fits in the groove of the rod and the seal member is locked to the rod, the seal member may come off between the rod and the retaining support member. To be prevented. (Mode 2) A film is formed on the surface of the cam of the retaining support member. According to such a configuration, the frictional resistance between the cam and the pusher member becomes small, so that the retaining support member can be smoothly operated. Note that electroless nickel plating or the like can be used as the above film.

[0008]

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing an entire jigsaw which is a reciprocating cutting tool. As shown in FIG. 1, the housing 2 of the jigsaw 1 has a grip handle 2a at the upper portion, and a base 3 for pressing against a workpiece is attached to the lower portion. A drive mechanism (not shown) having a motor is built in the housing 2, and the rotation output of the motor is transmitted to the front portion of the housing 2 to move the drive shaft 4 up and down. At the lower end of the drive shaft 4, a clamp device 10 for holding the upper end of a blade (blade) 5 is provided, which will be described in detail later. Reference numeral 30 in the drawing denotes an operating member attached to the front portion of the housing 2, and the operating member 30 unlocks the clamp device 10 (a state in which the blade can be attached / detached) and a locked state (a state in which the blade cannot be attached / detached). ) And switch. Further, 6 in the figure is a blade 5
The back roller is provided to prevent the shake of the motor, 7 is a trigger switch for turning on and off the rotation of the motor, and 8 is a power cable.

The blade 5 used in this jigsaw 1 will be described in advance. FIG. 12 shows a side surface of the blade 5. As shown in FIG. 12, the blade 5 is provided with a large number of blades 5a, and the blades 5a are pressed against a wood plate or the like to be cut while reciprocating, and cutting is performed. The base end upper surface 5d of the blade 5 is formed in a trapezoidal shape. Further, projections 5b, 5b for preventing removal are formed on the left and right side edges of the base end of the blade 5, and a constricted portion 5e is formed under the projections 5b. When the blade 5 is attached to the clamp device 10, the removal preventing protrusion 5b is provided.
The lower end surface of the member engages with the mating member and functions as a retaining member (details will be described later). The thickness of the blade 5 (the direction perpendicular to the plane of the drawing) differs depending on the object to be cut (wood board, annealed copper board, etc.) and the cutting method (high-speed cutting, saw cutting, etc.) (for example, 0.9 mm). ,
1.8 mm) is used.

The blade mounting device for mounting the blade 5 comprises a clamp device 10 and an operating member 30. The other parts use the conventionally known configuration, and the description thereof will be omitted. Hereinafter, each part of the blade attachment device will be described in detail.

FIG. 2 is a vertical sectional view of the clamp device 10. As shown in the figure, the drive shaft 4 has a lower end (tip) formed in a substantially tubular shape, and the rod member 1 is provided at the tip.
The base end of 2 is fitted and fixed. As well shown in FIGS. 3 and 4, the rod member 12 is formed with a slot 12a having a rectangular cross-section which is deeply cut upward from the lower end thereof and serves as an insertion portion. The blade 5 is inserted into the slot 12a. Slot 12
The bottom portion of a is formed in a trapezoidal shape that follows the upper surface 5d of the base end portion of the blade 5. Further, the rod member 12 has a hole 12 having a rectangular cross-sectional shape that reaches the slot 12a from the outer surface thereof.
b is formed. A push pin 13 having a sectional shape corresponding to the hole 12b is inserted into the hole 12b, and the push pin 13 is movable in the direction perpendicular to the axis of the drive shaft 4. That is, the push pin 13 as a pusher member is attached to the rod member 12 so that it can be brought into contact with or separated from the side surface of the blade 5 inserted into the slot 12a. The push pin 13 is pushed toward the inside of the slot 12a by its head portion 13b slidingly contacting the cam 16 of the blade guide 15 described below. As well shown in FIG. 4, the rod member 12 is formed with a flat surface 12k with which the head portion 13b of the push pin 13 pushed by the cam 16 abuts. A chamfered slope 13c is formed on the lower surface of the tip of the push pin 13 as shown in FIG. This is because the base end upper surface 5d of the blade 5 pushes the slope 13c when the blade 5 is inserted into the slot 12a,
The push pin 13 is prevented from being pushed back to the cam 16 side and obstructing the insertion of the blade 5.

The lower end 12c of the rod member 12 is formed to have an outer diameter slightly larger than the width dimension of the constricted portion 5e (see FIG. 12) of the blade 5, and the flange 12d is provided at a middle position in the height direction. Is formed and protrudes in the outer peripheral direction (however, the outer diameter of the lower end portion 12c is equal to that of the slot 1 described above).
Since it is smaller than the width dimension of 2a, the lower end portion 12c itself is divided into two parts, left and right. A blade guide 15 is attached to the rod member 12.

As shown in FIGS. 2 to 4, the blade guide 15 is formed in a shape in which a large-diameter and a small-diameter substantially cylindrical member are vertically connected, and a protrusion for preventing the blade 5 from coming off is formed on the bottom portion 15a. A through hole through which 5b can pass (also referred to as a through portion)
15b is provided. The lower end portion 12c of the rod member 12 is loosely fitted in the through hole 15b, and the outer peripheral surface of the flange portion 12d is loosely fitted in the cylindrical inner surface of the blade guide 15. Therefore, the blade guide 15 is the rod member 1.
It is possible to rotate around the rod member 12 while contacting the outer circumference of the rod 2. A groove 15c is formed on the inner surface of the upper side of the blade guide 15 along the circumference, and a retaining ring-shaped circlip 17 for a hole is fitted into the groove 15c to hold the blade guide 15 so as not to fall off. Has been done. Further, the upper surface of the bottom portion 15a of the blade guide 15 contacts the lower portion 12e of the rod member 12 (see FIG. 3; however, the state of direct contact is not shown in the same figure). Therefore, the blade guide 15 is mounted on the rod member 12 with its axial movement restricted. As shown in FIG. 4, the blade guide 15 has an arm-shaped protrusion 15d protruding outward from the outer periphery thereof.
Is formed, and the operating member 30 is provided at the tip of the protrusion 15d.
A hook-shaped hook portion 15e that can be engaged with (described later in detail) is formed. The blade guide 15 is the retaining support member according to the present invention.

As shown in FIG. 5, the through hole 15b allows a round hole having a diameter corresponding to the lower end 12c of the rod member 12 and the retaining projections 5b, 5b of the blade 5 to pass therethrough. It has a shape in which slit-shaped rectangular holes are overlapped. Then, the circular arc portion 15f formed by dividing the round hole
And a groove portion 15g which is both end portions of the rectangular hole are overlapped with each other, two corners of four corner portions (in the figure,
The portion indicated by the imaginary line) is a chamfered inclined surface 15h, and the opening of the groove 15g is widened diagonally to one side. The diameter of the round hole is slightly larger than the width of the constricted portion 5e of the blade 5, and the retaining projection 5b of the blade 5 can be locked at the edge of the arc portion 15f. On the other hand, the crossover dimension (total length of the slit) between the groove bottoms of the opposite groove portions 15g is the maximum width dimension 5c in the retaining projections 5b and 5b of the blade 5 (see FIG. 12).
It is formed slightly larger. The inclined surface 15h
Has a function of guiding the blade 5 to a regular position in the slot 12a when the blade 5 is obliquely inserted into the slot 12a. The specific operation will be described in detail later.

Further, the blade guide 15 is in sliding contact with the push pin 13 and regulates the position of the push pin 13 in accordance with the rotation angle with respect to the drive shaft 4.
Are formed. The shape of the cam surface of the cam 16 is well shown in FIG. That is, the blade guide 15
The axis (blade guide 15
The cam surface 16a that pushes the head 13b of the push pin 13 by changing the distance from the rotation axis of
(Range of C1) and the cam surface 16b (C which does not push the push pin 13 with a constant distance from the axis).
2)) are continuously provided. Also, cam 1
6, a stopper 16d protruding in the axial center direction is formed at the end of the cam surface 16b.
The rotation of the blade guide 15 can be regulated by bringing the side portion of the head portion 13b of the push pin 13 into contact with.

Further, a helical torsion spring 18 is mounted around the rod member 12 described above. This torsion spring 18 is shown in FIGS.
3, the one end 18a is held by the holding portion 15k formed on the protruding portion 15d of the blade guide 15, and the other end 18b is biased to the hole 12g formed in the rod member 12. It is plugged in. That is, the blade guide 15 is constantly urged in the arrow R direction by the torsion spring 18.

Further, at the upper end of the blade guide 15,
As shown in FIGS. 2 and 3, a dust cover 19 for dust prevention is attached so as to close an upper clearance between the dust cover 19 and the rod member 12. The dust cover 19 is formed of an elastic member such as rubber, and the ring-shaped main body portion is fitted between the rod member 12 and the blade guide 15 in a press-fitted state. Further, in this embodiment, the rod member 12 is formed with an outer peripheral groove 12h having a rectangular cross section.
The inner peripheral edge portion 19a of the dust cover 19 is inserted into the h to prevent slipping off in the axial direction (vertical direction). That is, as compared with the cap (dust cover) having a structure in which the outer peripheral groove 12h and the inner peripheral edge portion 19a do not engage with each other in the axial direction and the mounting structure thereof, the dust cover 19 is more difficult to fall off.

By the way, the blade guide 15 is
Electroless nickel plating is applied as the surface treatment.
Therefore, compared with general rust prevention treatment (chromate treatment, zinc plating, etc.), the surface hardness is high and smooth, and the friction resistance is small, so that smooth rotation during operation is ensured.

Next, the operation member 30 will be described. The operation member 30 is formed of a transparent material to improve the visibility of the inside, and is attached to the lower front portion of the housing 2 as shown in FIG. As shown in FIGS. 6 and 7, the operating member 30 has a substantially horseshoe-shaped plan view, and a shaft hole 30a is formed at one end thereof. Then, by inserting the pin 2b into the shaft hole 30a, the operation member 30 is inserted into the pin 2 with respect to the housing 2.
It is mounted rotatably around b. Although not shown, the operation member 30 is always provided on the housing 2 side in the direction of arrow R (hereinafter, the direction of arrow R is the closing direction, and the opposite direction is the opening direction).
An urging mechanism such as a spring urging the operating member 3
And a catch mechanism that receives and holds 0 in the closed position.

At the other end of the operating member 30, the operating portion 30
b and the hanging portion 30c are formed. Operation unit 30b
Is formed so as to project outward so that the user can operate the operation member 30 to rotate it around the shaft 2b. On the other hand, the hanging portion 30c is formed so as to project in a direction (inner side) opposite to the operation portion 30b, and a hook-shaped hook portion 30d is formed at the tip thereof. This hanging portion 30c is
When the user rotates the operation member 30 in the opening direction, it is caught by the protruding portion 15d of the blade guide 15, so that the blade guide 15 follows the operation member 30.

Next, the operation of the blade mounting device constructed as described above will be described. FIG. 6 is a bottom view of the blade attaching device to which the blade 5 is not attached. In this state, the blade guide 15 is urged by the torsion spring 18 (see FIGS. 3 and 4), and the push pin 13 is pushed by the flat surface 12 of the rod member 12.
is in contact with k. Therefore, the cam 16 of the blade guide 15 cannot push the push pin 13 any further, and the blade guide 15 cannot rotate in the direction of arrow R in FIG. The operation member 30 is held in the closed state shown in FIG. 6 by a biasing mechanism and a catch mechanism (not shown). Further, as is clear from FIG. 6, in this state, even if an attempt is made to insert the blade 5 into the slot 12a,
The end of the circular arc portion 15f of the blade guide 15 is the slot 1
Since both ends of 2a are blocked, the entry is blocked.

When mounting the blade 5 on the clamp device, first, the operating portion 30b of the operating member 30 is operated with a finger to push in the opening direction. Then, the operation member 30 rotates around the shaft 2b, and the hooking portion 30c hooks on the protruding portion 15d of the blade guide 15. Therefore, the operating member 3
When a force is further applied to 0 in the opening direction, the blade guide 15
Rotates together with the operating member 30 to the unlock position (blade attachment / detachment position) shown in FIG. 8 against the biasing force of the torsion spring 18. In this unlocked position, the push pin 13 comes into contact with the stopper 16d of the cam 16 and further rotation of the blade guide 15 is restricted.
The blade guide 15 can be easily positioned at the unlock position. In this state, the wide (slit) portion of the through hole 15b, that is, the pair of groove portions 15g is in the same vertical direction as the slot 12a. Therefore, when the blade 5 is inserted into the slot 12a, the blade 5
The retaining projection 5b can pass through the groove portion 15g and the bottom portion 15a of the blade guide 15, so that the base end portion of the blade 5 is accommodated in the slot 12a. At this time, since the opening is widened by the inclined surface 15h of the through hole 15b, it is easy to insert the blade 5 into the slot 12a.

Next, the base end of the blade 5 is inserted into the slot 12
While maintaining the state of being fully inserted into the a, the operating member 30
When the force of the finger that was rotating the blade is reduced, the blade guide 1
5 and the operating member 30 are simultaneously rotated by the urging force of the torsion spring 18 to the pushing start position shown in FIG.
That is, during this period, since the head portion 13b of the push pin 13 faces the cam surface 16b having a constant radius, the force for pushing the push pin 13 in the direction perpendicular to the axis does not act. Therefore, regardless of the plate thickness of the blade 5 inserted into the slot 12a, the blade guide 15 rotates to the pushing start position. At the pushing start position, the retaining projection 5b of the blade 5 is separated from the groove 15g and hangs on the edge of the arc portion 15f, so that the retaining projection 5b is reliably supported (prevented) by the blade guide 15. Further, since the force from the push pin 13 does not act on the blade 5 from the unlock position to the pushing start position,
Even when the blade 5 is obliquely inserted into the slot 12a, the blade is guided by the inclined surface 15h of the through hole 15b to be in the normal position. Therefore, the operation of the blade guide 15 described below is smoothly performed.

Subsequently, the blade guide 15 and the operating member 30 are simultaneously rotated by the urging force of the torsion spring 18 to the lock position of the blade guide 15 shown in FIG. During this time, the head portion 13b of the push pin 13 is brought into sliding contact with the cam surface 16a, so that the push pin 13 is pushed forward in the direction perpendicular to the axis line, and the tip thereof pushes the blade 5 against one side surface of the slot 12a. Blade 5 in slot 1
When the push pin 13 is pressed against one side surface of the blade 2a, the push pin 13 cannot be advanced any more, so that the rotation of the blade guide 15 in the closing direction is locked. As a result, the blade 5 is held in the slot 12a without rattling, and by extension,
It is possible to support blades with different thickness. By the way, the cam surface 16a is shown in FIG.
As shown in 0 (b), the head 13 of the push pin 13
An angle F formed by a common tangent line Lt at a contact point P with b and a straight line Lv passing through the contact point P and passing through the contact point P and the center of the rotation axis (in the present specification, "friction angle"). (Also referred to as “”) is set within the range of 12 ° to 16 °. As a result, the force for clamping the blade 5 is sufficient within the rotation range in which the cam surface 16a (range C1 in FIG. 5) functions, and the pusher pin 13 and the cam surface 16
It creates a situation where a cannot bite.

From the state shown in FIG. 10, the push pin 13
Since there is no displacement of the blade guide 15, the blade guide 15 is locked, only the operating member 30 rotates to the closed position shown in FIG. 11, and the blade guide 15 and the operating member 30 are brought into a non-contact state. The torque for rotating the operation member 30 at this time is applied via the above-mentioned biasing mechanism (not shown),
A catch mechanism (not shown) holds it in the closed position. This completes the mounting of the blade 5. The procedure for removing the blade 5 is the same as the preparatory operation in the previous stage when the blade is mounted, and therefore the description thereof is omitted to avoid repetition. In this embodiment, an example of the blade 5 having a relatively thin plate is shown, but a blade that can be inserted into the slot 12a can be used even if it has a thickness that leaves substantially no gap.

As is clear from the above description, in the jigsaw according to this embodiment, the retaining projections 5b of the blade 5 are
The blade guide 15 that locks the blade 5b can rotate from the unlock position to the pushing start position regardless of the plate thickness of the blade 5. Therefore, the retaining projections 5b, 5b of the blade 5 and the blade guide 15 can be reliably locked, and the blade 5 can be reliably prevented from coming off.

Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. Further, the technical elements described in the present specification or the drawings are
The technical usefulness is exhibited alone or in various combinations, and is not limited to the combinations described in the claims at the time of filing. Further, the technique illustrated in the present specification or the drawings achieves a plurality of purposes at the same time, and achieving the one purpose among them has technical utility.

[Brief description of drawings]

FIG. 1 is a side view showing a jigsaw according to an embodiment.

FIG. 2 is a vertical sectional view of a clamp device.

3 is a sectional view taken along line III-III in FIG.

4 is a sectional view taken along line IV-IV of FIG.

FIG. 5 is a plan view of a blade guide.

6 is a bottom view of the blade attaching device, which corresponds to the arrow A of FIG. 1 in a state where the blade is not attached.

FIG. 7 is a perspective view of an operation member.

FIG. 8 is an operation explanatory view of the blade attaching device,
(A) shows a state where the operating member and the blade guide are in the open position, and (B) shows a cam position at that time.

FIG. 9 is an explanatory view of the operation of the blade attaching device,
(A) shows a state where the operation member and the blade guide are at the pushing start position, and (B) shows a cam position at that time.

FIG. 10 is an operation explanatory view of the blade attaching device,
(A) shows a state where the operating member and the blade guide are in the lock position, and (b) shows a cam position at that time.

FIG. 11 is an operation explanatory view of the blade attaching device,
(A) shows the state where the operating member is in the closed position, and (B) shows the cam position at that time.

FIG. 12 is a side view of the blade.

[Explanation of symbols]

1 ... Jigsaw 2 ·· Housing 4 ・ ・ Drive shaft 5 ・ ・ Blade 5b ... Prevention protrusion 10 Clamping device 12 ... Rod members 12a slot (insertion part) 13 ... Pushpin 15 ... Blade guide 15b / through hole 16 ... Cam 30..Operating members

Claims (3)

[Claims] 1. A reciprocating cutting tool comprising a blade attaching device for attaching a blade having a retaining projection on a side edge of a base end portion to a reciprocating drive shaft, wherein the blade attaching device is fixed to a lower end portion of the drive shaft. A rod member having an insertion portion formed so that the blade base end portion can be inserted upward along the axis of the drive shaft; and a blade base end portion that is attached to the rod member and inserted into the insertion portion. The pusher member is formed so as to be movable in the direction of coming into contact with or away from the side surface, and the rod member has a penetrating portion that is mounted so as to be rotatable around the axis line and through which the retaining projection can pass, and that penetrating portion. A retaining member formed so as to be locked at a position rotated around the axis with respect to the retaining protrusion that has passed through the stopper protrusion, and the retaining member is provided with a pusher member in response to a rotation operation of the retaining support member. At right angles to the axis A cam that pushes in the direction is provided, and the cam rotates from the blade attachment / detachment position where the removal support member can insert the blade base end portion to the insertion portion to the pushing start position that is rotated by a predetermined angle. A reciprocating cutting tool characterized in that the pusher member is not pushed while being operated, and is pushed further by being further rotated from the pushing start position. 2. A common normal line at the contact point between the cam and the pusher member and a line segment from the contact point to the rotation center of the cam when the retaining support member is further rotated from the pushing start position. The reciprocating cutting tool according to claim 1, wherein the angle is in the range of 12 ° to 16 °. 3. The reciprocal cutting according to claim 1, wherein a taper surface for guiding the blade to a regular position is formed at a part of a hole edge portion of a through portion of the retaining support member. tool.