JP2015139869A - Reciprocation cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the occurrence of vibrations resulting from a counterweight.SOLUTION: A jig saw 1 includes: a motor 5; a rod 33 to which a blade 37 may be attached; a reciprocation mechanism 31 which converts rotation of the motor 5 into reciprocating motion of the rod 33; a counterweight 48 which symmetrically reciprocates in the same direction as the reciprocating motion of the rod 33; a guide plate 60 which guides reciprocating motion of the counterweight 48; and pre-load means (a rubber pin 65) which presses the guide plate 60 to the counterweight 48.

Description

  The present invention relates to a reciprocating cutting tool such as a jigsaw that reciprocates a blade to cut a workpiece.

  For example, in a reciprocating cutting tool such as a jigsaw or reciprocating saw, the rotation of the output shaft of the motor is converted into a reciprocating motion of a slide member such as a slider or a rod via a crank mechanism, and the blade attached to the slide member is reciprocated together. To cut the material to be cut. In such a reciprocating cutting tool, as disclosed in Patent Document 1, a balance plate (counterweight) that moves up and down symmetrically with the vertical movement of the rod is provided to suppress vibrations associated with the vertical movement of the rod. Things are known.

Japanese Patent Laid-Open No. 11-5201

  Such a counterweight is effective in suppressing the vibration of the rod when the weight part with a large mass is arranged on the extension line of the rod, but when the weight part moves up and down, a moment in the front-rear direction is generated, There was a risk of vibration. Although it is conceivable to provide a guide member for guiding the vertical movement of the weight portion, if the weight portion moves in the front-rear direction, the guide action by the guide member is reduced, which is insufficient for preventing vibration.

  Therefore, an object of the present invention is to provide a reciprocating cutting tool that can effectively prevent generation of vibration due to a counterweight.

In order to achieve the above object, a first aspect of the present invention is directed to a motor, a slide member to which a blade can be attached, a reciprocating mechanism for converting the rotation of the motor into a reciprocating motion of the slide member, A reciprocating cutting tool comprising a counterweight that reciprocates symmetrically in the same direction as the movement, and a guide member that guides the reciprocating movement of the counterweight, and is provided with a preload means that presses the guide member against the counterweight It is characterized by.
The preload means is not limited to the one that acts only on the guide member, but includes one that relatively presses the guide member against the counterweight by acting on the counterweight.
According to a second aspect of the present invention, in the configuration of the first aspect, the counterweight includes a plate that reciprocates in parallel with a slide member that reciprocates in the vertical direction, and a weight that is attached to the plate. It is provided in front of the weight, and is pressed against the weight by preload means disposed in front of the guide member.
According to a third aspect of the present invention, in the configuration of the first or second aspect, the preloading means is an elastic body that makes line contact with the guide member.
According to a fourth aspect of the present invention, in the configuration of the third aspect, a plurality of types of elastic bodies are provided.
According to a fifth aspect of the present invention, in the configuration of the fourth aspect, the guide member has elasticity and is also used as one elastic body.
The invention according to claim 6 is characterized in that, in the structure according to any one of claims 2 to 5, a concave groove into which the guide member is fitted is provided in the weight.
The invention according to claim 7 is the structure according to any one of claims 3 to 6, wherein the guide member is fixed at one end side in the reciprocating direction of the counterweight and the other end side is a free end, and the counterweight is supported by an elastic body. It is characterized by being pressed against.
The invention according to claim 8 is the structure according to any one of claims 3 to 7, wherein the slide member and the counterweight reciprocate in the vertical direction, and the elastic body is at the top dead center of the counterweight. It is located above the lower end position of the weight contacting the guide member.
According to a ninth aspect of the present invention, in the configuration of any of the second to eighth aspects, the slide member and the counterweight reciprocate in the vertical direction, and the weight is a droop projecting downward at the front portion. It has the part.

According to the first aspect of the present invention, it is possible to effectively prevent the occurrence of vibration due to the counterweight by providing the preload means for pressing the guide member against the counterweight.
According to the second aspect of the present invention, in addition to the effect of the first aspect, the guide member is provided in front of the weight that reciprocates in the vertical direction and is pressed against the weight by the preloading means disposed in front of the weight. As a result, the assembling property is improved.
According to invention of Claim 3, in addition to the effect of Claim 1 or 2, the preload to the guide member can be easily provided by making the preload means an elastic body.
According to the fourth aspect of the invention, in addition to the effect of the third aspect, by providing a plurality of types of elastic bodies, vibration suppression can be achieved more effectively with different natural frequencies.
According to the fifth aspect of the present invention, in addition to the effect of the fourth aspect, the guide member has elasticity and is also used as one elastic body. It becomes composition.
According to the sixth aspect of the present invention, in addition to the effect of any one of the second to fifth aspects, the weight is provided with the concave groove into which the guide member is fitted, so that the guide member can move up and down. In addition, it is possible to prevent the counterweight from moving to the left and right.
According to the seventh aspect of the present invention, in addition to the effect of any of the third to sixth aspects, the guide member is elastically configured such that one end side of the counterweight in the reciprocating direction is fixed and the other end side is a free end. Since the body is pressed against the counterweight, a stable preload can be applied.
According to the eighth aspect of the invention, in addition to the effect of any one of the third to seventh aspects, the elastic body is positioned above the lower end position of the weight contacting the guide member at the top dead center of the counterweight. As a result, it is possible to obtain a buffering action when the counterweight descends from the top dead center.
According to the ninth aspect of the invention, in addition to the effect of any of the second to eighth aspects, the weight has a drooping portion projecting downward at the front portion, so that the thickness in the front-rear direction is increased. It is possible to achieve compactness by suppressing.

It is the center longitudinal cross-sectional view of a jigsaw (a rod is a top dead center). It is an AA line expanded sectional view of FIG. It is a BB line expanded sectional view of Drawing 1. It is a perspective view of a counterweight. (A) is a front view of a counterweight, (B) is a EE sectional view. FIG. 2A is an enlarged sectional view taken along line CC in FIG. 1, and FIG. 2B is an enlarged sectional view taken along line DD in FIG. It is a center longitudinal cross-sectional view of the output part of a jigsaw (a rod is a bottom dead center). It is the FF sectional view taken on the line of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a central longitudinal sectional view of a jigsaw 1 which is an example of a reciprocating cutting tool, FIG. 7 is an enlarged view of an output unit, FIG. 1 shows a rod located at a top dead center, and FIG. ing. The jigsaw 1 is constructed by assembling left and right halved housings, and includes a base 3 below a housing 2 that houses a motor 5 and an output unit 7. A battery pack 4 serving as a power source is attached to the rear portion of the housing 2 (the right side in FIG. 1 is the front).
The motor 5 is housed in a motor housing portion 8 that extends forward and backward at the lower part of the housing 2 with the output shaft 6 facing forward. A loop-shaped handle 9 is formed on the upper portion of the housing 2, and a switch 10 having a trigger 11 is accommodated therein.

  An inner housing 12 in which a rear gear housing 13 and a front gear housing cover 14 are assembled is provided in front of the motor accommodating portion 8, and the output portion 7 is accommodated in the inner housing 12. The lower portion of the gear housing 13 is a connecting portion 15 protruding from the housing 2, and the base 3 is connected to the connecting portion 15. The output shaft 6 of the motor 5 projects from the inner housing 12 a pinion that is pivotally supported by a bearing 16 provided in the gear housing 13 and formed at the tip. A support pin 17 parallel to the output shaft 6 is supported on the gear housing 13 above the output shaft 6 so as to protrude into the inner housing 12, and a gear that meshes with the pinion of the output shaft 6 on the support pin 17. 18 is rotatably supported via a bearing 19. An eccentric pin 20 is fixed forwardly at an eccentric position of the gear 18, and a guide roller 21 is rotatably provided at the tip thereof via a bearing 22. The guide roller 21 is a slider having a U-shaped cross section. 23 so as to be able to roll. On the other hand, on the rear surface of the gear 18, the eccentric position that is 180 ° out of phase with the eccentric pin 20 has a first eccentric portion 25 on the proximal end side with a large eccentric amount and a second eccentric portion 26 on the distal end side with a small eccentric amount. A stepped eccentric boss 24 made of

  As shown in FIG. 2, four bosses 27, 27... Project from the inner surface of the gear housing cover 14, and a U-shaped guide plate 28 is formed on the boss 27 by screws 29, 29. Overhang portions (not shown) provided at both ends of the slider 23 are fitted to the bent portions 30 provided on the left and right sides of the guide plate 28. Thus, the slider 23 is supported in the inner housing 12 so as to be movable up and down, and when the gear 18 rotates and the guide roller 21 moves eccentrically together with the eccentric pin 20, the amount of displacement of the guide roller 21 in the vertical direction is transmitted to the slider 23. 23 moves up and down via the guide roller 21. The gear 18, the eccentric pin 20, the guide roller 21, and the slider 23 constitute a reciprocating mechanism 31 that converts the rotation of the motor 5 into a reciprocating movement of a rod 33 described later.

As shown in FIG. 3, a pair of support pieces 32, 32 projecting downward is provided at the center of the lower surface of the slider 23, and the upper end of a rod 33 as a slide member is interposed between the support pieces 32, 32. The pins 34 are connected. The rod 33 has a prismatic shape, passes through a bush 35 held at the lower portion of the gear housing cover 14 and protrudes downward from the inner housing 12. The upper end of the blade 37 is connected to the joint portion 36 provided at the lower end. It can be installed.
Further, on the front side of the rod 33, a regulating roller 38 that regulates the forward swing of the rod 33 is disposed. The regulating roller 38 is attached to a lower end of a leaf spring 39 fixed by a screw 29 for screwing the guide plate 28, and always presses the rod 33 backward.

  On the other hand, an orbital mechanism 40 is provided behind the rod 33 to move the blade 37 moving up and down together with the rod 33 back and forth to make an elliptical locus movement. The orbital mechanism 40 includes a cam plate 41 that moves up and down in conjunction with the second eccentric portion 26 of the eccentric boss 24 of the gear 18 and a swing arm 42 that is positioned below the cam plate 41. The swing arm 42 is formed by bending the middle portion of the belt plate in an inverted U shape and supporting the back roller 43 at the lower end, and between the pair of left and right connecting pieces 44, 44 provided on the connecting portion 15 of the gear housing 13. In the normal state, the pin 45 is supported so as to be able to swing back and forth. However, under the normal condition, the weight of the back roller 43 urges the upper end to rotate to a position where it abuts the lower end of the top dead center cam plate 41 as shown in FIG. ing. When the cam plate 41 is lowered, the cam plate 41 pushes down the upper end of the swing arm 42 to swing the back roller 43 forward as shown in FIG.

46 is a semi-cylindrical switching shaft that penetrates the connecting portion 15 in the left-right direction above the upper end of the swing arm 42, and is operated by a lever 47 provided on the side surface of the connecting portion 15 so that the curved surface is downward. The curved surface comes into contact with the upper end of the swing arm 42 and the swing of the swing arm 42 is restricted. On the contrary, when the operation is performed so that the curved surface is on the upper side, the curved surface is separated from the upper end of the oscillating arm 42, so that the oscillating arm 42 is allowed to oscillate.
Therefore, when the switching shaft 46 is switched so as to allow the swinging of the swinging arm 42, the eccentric pin 20 and the eccentric boss 24 are offset from each other on the opposite side. The back roller 43 swings forward and pushes the blade 37 forward as the blade 37 rises in order to lower and push down the upper end of the swing arm 42. When the rod 33 descends, the cam plate 41 rises. Therefore, the back roller 43 swings backward and separates from the blade 37 because it separates from the upper end of the swing arm 42. Thus, the blade 37 pushed by the back roller 43 when ascending moves orbitally back and forth.

  A counterweight 48 is provided in the inner housing 12. The counterweight 48 includes a plate 49 provided between the gear 18 and the cam plate 41 and a weight 50 supported by the plate 49. First, as shown in FIGS. 4 and 5, the plate 49 has an inverted L-shape comprising a vertical cam plate portion 51 and a weight mounting portion 52 that protrudes forward from the upper end of the cam plate portion 51. A cam hole 53 having a vertical width in which the first eccentric portion 25 is fitted and a lateral width that allows the eccentric motion of the first eccentric portion 25 is formed in the central portion of the plate portion 51. A long hole 54 through which the output shaft 6 passes is formed.

  Therefore, when the gear 18 rotates and the eccentric boss 24 moves eccentrically, the vertical displacement of the first eccentric portion 25 is transmitted to the cam plate portion 51, and the plate 49 moves up and down. In addition, above the gear 18 on the inner surface of the gear housing 13, as shown in FIG. 6A, both plates 41, 49 are provided by a pair of ribs 55, 55 erected on the left and right of the cam plate 41 and the plate 49. As shown in FIG. 5B, the two plates are connected between a pair of left and right connecting pins 56, 56 that connect the gear housing 13 and the gear housing cover 14, below the output shaft 6. The vertical movement of 41 and 49 is guided.

  The weight 50 is a metal block body that is attached to the front lower surface of the weight attachment portion 52 of the plate 49 by a pair of left and right screws 57 and is positioned above the top dead center slider 23 in the attached state. The part is formed with a drooping portion 58 protruding downward in front of the slider 23. With this shape, a necessary mass can be ensured while the size of the weight 50 in the front-rear direction is made compact. The center of gravity of the counterweight 48 is positioned directly above the rod 33, and the total weight of the counterweight 48 is set to be balanced with the total weight of the rod 33, the blade 37, and the slider 23. A concave groove 59 in the vertical direction is formed on the front surface of the weight 50, and a notch 52 a continuous with the concave groove 59 is formed in the center of the front end of the weight mounting portion 52 of the plate 49. The concave groove 59 is formed so that the upper side is shallower than the lower side.

  Further, a guide plate 60 as a guide member is provided in front of the counterweight 48. The guide plate 60 is a belt-like plate having a width that fits into the concave groove 59 of the weight 50, and a wide attachment portion 61 is formed on the left and right at the lower end. The attachment portion 61 is positioned below the weight 50. Thus, a pair of small bosses 62 and 62 projecting from the inner surface of the gear housing cover 14 are fixed by screws 63 between the bosses 27 to which the guide plate 28 is screwed. Therefore, the guide plate 60 is supported at a position spaced apart from the inner surface of the gear housing cover 14 with elasticity in the front-rear direction and elastically guides the weight 50. However, a cylindrical rubber pin 65 is disposed between the upper end, which is a free end of the guide plate 60, and the gear housing cover 14 so as to be held laterally by a receiving seat 64 provided on the inner surface of the gear housing cover 14. Yes. The rubber pin 65 has the same width as the guide plate 60 and is in line contact with the upper end of the guide plate 60, thereby applying a preload to the guide plate 60 and elastically pressing the guide plate 60 against the weight 50. 65 is the preload means (elastic body) of the present invention.

In the jigsaw 1 configured as described above, when the base 3 is set on the material to be cut with the blade 37 attached to the rod 33 and the trigger 11 is pushed in, the switch 10 is turned on and the motor 5 is driven. Then, the output shaft 6 rotates to decelerate and rotate the gear 18. Due to the rotation of the gear 18, the eccentric pin 20 moves eccentrically and moves the slider 23 and the rod 33 up and down via the guide roller 21, so that the blade 37 moves up and down and the material to be cut is cut.
At this time, the cam plate 41 of the orbital mechanism 40 moves up and down due to the eccentric movement of the eccentric boss 24 of the gear 18, so that if the switching shaft 46 is switched to the swing allowable position of the swing arm 42, the swing arm 42 swings back and forth, and the back roller 43 presses the blade 37 forward as the blade 37 rises. However, excessive movement forward of the blade 37 pushed forward is restricted by the restriction roller 38.

  The eccentric weight of the eccentric boss 24 causes the counterweight 48 to move up and down symmetrically with the rod 33 as shown in FIGS. 1 to 3 and FIGS. Can be suppressed. In particular, here, the weight 50 of the counterweight 48 moves up and down while being guided by the guide plate 60. However, since the guide plate 60 is elastically pressed against the weight 50 by the rubber pin 65, the weight 50 moves forward. Movement is restricted, the generation of moment is suppressed, the vertical movement is stabilized, and the occurrence of vibration associated with the vertical movement of the counterweight 48 can be effectively prevented. Further, the weight 50 moves up and down while the guide plate 60 is fitted in the concave groove 59, so that the counterweight 48 can be prevented from shaking left and right. Further, at the top dead center of the counterweight 48 shown in FIG. 7, since the rubber pin 60 is located above the lower end position of the concave groove 59 that contacts the guide plate 60, the impact when descending from the top dead center is applied. It can be absorbed by the rubber pin 60.

Thus, according to the jigsaw 1 of the said form, by providing the preload means (rubber pin 65) which presses the guide plate 60 to the counterweight 48, generation | occurrence | production of the vibration resulting from the counterweight 48 can be prevented effectively. Become.
Particularly, since the guide plate 60 is provided in front of the weight 50 that moves up and down and is pressed against the weight 50 by the rubber pin 65 in front of the weight 50, the assemblability is improved.
In addition, since the rubber pin 65 that makes line contact with the guide plate 60 is employed as the preloading means, preloading to the guide plate 60 can be easily applied.
Further, since the guide plate 60 has elasticity and is pressed against the weight 50 by the rubber pin 65, the vibration is effectively suppressed by different natural frequencies of the guide plate 60 and the rubber pin 65 with a rational configuration with a small number of parts. can do.

Further, by providing the weight 50 with the concave groove 59 into which the guide plate 60 is fitted, it is possible to prevent the counterweight 48 from shaking left and right in addition to the vertical movement guide by the guide plate 60.
Further, since the lower end side of the guide plate 60 is fixed and the upper end side is a free end and is pressed against the counterweight 48 by the rubber pin 65, a stable preload can be applied.
Further, since the rubber pin 65 is disposed above the lower end position of the concave groove 59 of the weight 50 that contacts the guide plate 60 at the top dead center of the counterweight 48, the buffer weight when the counterweight 48 descends from the top dead center is set. The effect can be obtained.
In addition, since the weight 50 has a drooping portion 58 that protrudes downward at the front portion, the thickness in the front-rear direction can be suppressed and downsizing can be achieved.

In the above embodiment, a rubber pin is used as the preload means. However, the shape of the rubber pin is not limited to a cylindrical shape, and a quadrangular shape, a polygonal shape, or the like can be used. In addition, the guide member may be preloaded by combining a plurality of elastic bodies (rubbers, coil springs, leaf springs, etc.) having different natural frequencies without being limited to one elastic body. If a plurality of types of elastic bodies are used in this way, vibration suppression can be achieved more effectively with different natural frequencies.
Further, the preload means is not limited to the case where the preload means is applied to the guide weight such as the guide plate and pressed against the counterweight, but the preload means is provided on the counterweight side to be applied to the counterweight and the fixed guide member is relatively moved. It is also possible to press against the counterweight.

On the other hand, the specific structure of the counterweight is not limited to the above-described form. For example, a long hole provided in the guide member by eliminating the hanging part of the weight, or by using a plurality of parts, or by providing a ridge instead of the groove. The upper and lower guides and the left and right shakes can be prevented by fitting them to each other.
In addition, other structures of the jigsaw are not limited to the above-described forms, such as a structure in which a plurality of gears are provided, a structure in which there is no upper handle and the motor housing is also used as a handle, and a structure that uses a commercial power supply instead of a battery pack. .
The present invention is not limited to a jigsaw, and any other reciprocating cutting tool such as a reciprocating saw can be used as long as it includes a slide member, a counterweight, and a guide member that guides the counterweight's reciprocating motion. Is possible.

  1. ・ Jigsaw, 2. ・ Housing, 3. ・ Base, 5. ・ Motor, 6. ・ Output shaft, 7. ・ Output part, 12. ・ Inner housing, 13. ・ Gear housing, 14. ・ Gear housing cover , 18 .. Gear, 20.. Eccentric pin, 23 .. Slider, 24.. Eccentric boss, 25 .. First eccentric part, 26 .. Second eccentric part, 31 .. Reciprocating mechanism, 33. 37, Blade, 40, Orbital mechanism, 41, Cam plate, 42, Swing arm, 43, Back roller, 48, Counterweight, 49, Plate, 50, Weight, 58, Suspended portion, 59 ... groove, 60 ... guide plate, 65 ... rubber pin.

Claims (9)

A motor,
A slide member to which a blade can be attached;
A reciprocating mechanism for converting rotation of the motor into reciprocating movement of the slide member;
A counterweight that reciprocates symmetrically in the same direction as the reciprocating movement of the slide member;
A reciprocating cutting tool comprising a guide member for guiding reciprocating movement of the counterweight,
A reciprocating cutting tool comprising preload means for pressing the guide member against the counterweight.   The counterweight includes a plate that reciprocates in parallel with the slide member that reciprocates in the vertical direction, and a weight attached to the plate, and the guide member is provided in front of the weight, and the guide member The reciprocating cutting tool according to claim 1, wherein the preload means is pressed against the weight by the preloading means disposed in front of the reciprocating cutting tool.   The reciprocating cutting tool according to claim 1 or 2, wherein the preload means is an elastic body that comes into line contact with the guide member.   The reciprocating cutting tool according to claim 3, wherein a plurality of types of elastic bodies are provided.   The reciprocating cutting tool according to claim 4, wherein the guide member has elasticity and is also used as one elastic body.   The reciprocating cutting tool according to any one of claims 2 to 5, wherein a concave groove into which the guide member is fitted is provided in the weight.   7. The guide member according to claim 3, wherein one end side of the counterweight in the reciprocating direction is fixed and the other end side is a free end and is pressed against the counterweight by the elastic body. The reciprocating cutting tool described.   The slide member and the counterweight reciprocate in the vertical direction, and the elastic body is located above the lower end position of the weight that contacts the guide member at the top dead center of the counterweight. A reciprocating cutting tool according to any one of claims 3 to 7.   9. The slide member and the counterweight reciprocate in the vertical direction, and the weight has a drooping portion protruding downward at a front portion. Reciprocating cutting tool.

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