JP2005046922A - Impact function limiting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily divert a tool with an impact function to a power tool such as a polishing tool or a drilling tool by safely and positively limiting the impact function of the tool with the impact function with simple constitution. <P>SOLUTION: In the tool 10 with the impact function, a rotary shaft 26 driven by a driving motor is mounted with a hammer 25 in a rotatable and axially reciprocating manner by a cam mechanism. An anvil 29 for transmitting the torque of the rotary shaft 26 to an output shaft 13 at the tip of the tool is engaged with the hammer 25. An impact function limiting device 30 has spacers 32, 33 in place of a compression spring for energizing the hammer 25 to the anvil 29 side at the rotary shaft 26, and the axial position of the hammer 25 is regulated by the end faces of the spacers 32, 33 so that the hammer 25 and the anvil 29 are placed in the engaging position. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an impact function limiting device, and is applied to a tool with an impact function such as an electric screwdriver or a wrench.
[0002]
[Prior art]
Conventionally, a tool with an impact function that automatically tightens screws and bolts is known. In this type of tool, when a certain load is applied to the output shaft at the tip of the tool, impact is applied in the tightening direction to increase the tightening force.
[0003]
In the configuration of the tool with an impact function, for example, a hammer is attached to a rotating shaft that is rotated by a drive motor, and an anvil is provided on the hammer so as to be engageable. An output shaft is provided at the tip of the anvil, and a fastener such as a driver is attached to the output shaft. The driving force of the driving motor is transmitted to the fastening tool through the hammer and the anvil.
A compression spring that urges the hammer toward the anvil is attached to the rotating shaft. When the hammer is pushed by the compression spring and held on the anvil side, the hitting claw at the tip of the hammer hits the locking claw of the anvil.
When a load exceeding a certain level is applied to the output shaft, the hammer moves in a direction away from the anvil against the urging force of the compression spring by the cam mechanism between the rotating shaft and the hammer. At the same time as the hammer hitting pawl is released from the anvil locking pawl, the compression spring pushes the hammer along the cam groove, and the hammer hitting pawl is rotated around the rotation axis to disengage the anvil locking pawl. Stroke in the direction of rotation.
[0004]
In addition to the AC power source, the impact function tool includes a cordless type equipped with a rechargeable battery, and various devices are provided for improving portability and workability. In addition, as a prior art regarding a tool with an impact function, the following patent documents 1 and 2 etc. are mentioned.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-40258 [Patent Document 2]
Japanese Patent Laid-Open No. 2002-273666
[Problems to be solved by the invention]
On the other hand, recently, a multifunctional tool excellent in portability and workability has been demanded. The present inventors have proposed to improve the structure of the above-mentioned tool with an impact function and apply the rotational force to a power tool such as a buff or a drill. That is, instead of using a tool such as a screwdriver or a wrench at the tip of a tool with an impact function, if you use a tool such as a buff or a drill, you can efficiently use its rotational force. An extremely convenient power tool is realized.
[0007]
However, if a tool such as a buff or drill is attached to a tool with an impact function, an impact force acts in the rotational direction when a load exceeding a certain level is applied to the rotating shaft. In addition, due to the relationship between the motor torque and the biasing force of the compression coil spring, only the impact is performed while the processing tool is stopped. As a result, the polishing operation and the drilling operation are hindered, and simply attaching a buff or a drill to the output shaft of the tool with an impact function is not practical.
[0008]
The present invention has been made in view of such a current situation, and by safely and reliably limiting the impact function of a tool with an impact function with a simple configuration, the tool with an impact function can be used as an electric tool such as a polishing tool or a punching tool. It is an object of the present invention to provide an impact function limiting device that can be easily transferred to a tool.
[0009]
[Means for Solving the Problems]
An impact function limiting device according to the present invention for solving the above-mentioned problems is
A rotating shaft driven by a drive motor;
A hammer attached to the rotating shaft by a cam mechanism and reciprocally mounted in the axial direction;
An anvil that engages the hammer and transmits the rotational force of the rotary shaft to the output shaft at the tip of the tool;
In a tool with an impact function provided with a compression spring attached to the rotating shaft and biasing the hammer toward the anvil side,
The rotary shaft is provided with a spacer instead of the compression spring, and the axial position of the hammer is regulated by the end face of the spacer so that the hammer and the anvil are in the engagement position.
[0010]
According to the impact function limiting device of the present invention, the hammer is fixed at the engagement position with the anvil by setting the spacer instead of the compression spring on the rotating shaft of the tool with the impact function. That is, since the hammer is fixed at the engagement position of the rotating shaft, even if a load is applied to the output shaft, the cam mechanism does not work and the hammering action is limited. As a result, even if a processing tool such as a buff or a drill is attached to the output shaft, the striking force due to the impact function does not act on the processing surface, so that workability can be improved.
[0011]
The impact function limiting device of the present invention (second invention) is characterized in that the spacer comprises two or more split spacers, and these split spacers are fixed to the rotating shaft by a fixing means. .
[0012]
Generally, a cam mechanism of a tool with an impact function has a structure in which a steel ball is inserted into a cam groove between a rotating shaft and a hammer. When assembling, usually, after setting the compression spring on the rotating shaft, the hammer is pushed in the compression direction and the steel ball is inserted into the cam groove with the compression spring contracted. In other words, if the hammer is in the engagement position of the rotating shaft, the steel ball cannot be inserted into the cam groove, so the hammer is temporarily displaced in the compression direction of the compression spring and the steel ball is inserted into the cam groove. .
In the impact function limiting device according to the present invention (first invention), an integral ring-shaped spacer may be used as the spacer. However, according to such a ring-shaped spacer, the ring-shaped spacer becomes an obstacle. There arises a problem that the steel ball cannot be inserted into the cam groove. For this reason, measures such as changing the cam mechanism having the above-described structure are required.
[0013]
According to the present invention (second invention), since the spacer is composed of two or more split spacers, the steel ball is inserted into the cam groove between the rotating shaft and the hammer first, and then the hammer is engaged. While maintaining the position, a split spacer can be retrofitted to the rotating shaft. That is, since the split spacer can be attached from the side of the rotating shaft, the impact function limiting device can be incorporated into the tool with an impact function without changing the structure of the cam mechanism described above. As a result, the assembly of the impact function restriction device becomes extremely simple, and the impact function can be reliably restricted at low cost.
The shape of the split spacer is not particularly limited as long as it is attached from the side of the rotating shaft. Examples thereof include a combination of semicircular split spacers and a combination of rectangular split spacers. In order to reduce the number of parts, the number of split spacers is preferably a pair (two).
[0014]
In the impact function restriction device of the present invention (third invention), the fixing means for the split spacer is a snap ring, and a concave groove for receiving the snap ring is formed on the outer peripheral surface of the split spacer. It is characterized by that.
[0015]
In the impact function limiting device according to the present invention (second invention), examples of the means for fixing the split spacer include a bolt and a nut. By sandwiching the rotating shaft between the split spacers and tightening the bolts and nuts from both sides, the split spacer can be fixed to the rotating shaft.
However, when the split spacer is fixed to the rotary shaft with the bolts and nuts as described above, the bolts and nuts may be loosened due to vibration of the rotary shaft or the like when the operator's tightening force is insufficient.
According to the third aspect of the present invention, since the split spacer is tightened with the snap ring, the split spacer can always be fixed to the rotating shaft with a constant and strong tightening force. Further, since the snap ring fits into the concave groove, the snap ring does not come off from the split spacer even if vibration or the like occurs on the rotating shaft. As a result, the reliability of the tool can be greatly improved.
[0016]
The tool to which the impact function restriction device of the present invention (first to third inventions) is applied may be a rechargeable battery type electric tool. In particular, the present invention (first to third inventions) may be applied to a rechargeable battery type rotary polishing tool (such as a polisher or a sander).
Conventionally, there are no commercially available rotary polishing tools that employ a rechargeable battery, and few cordless and easy-to-use tools are known. According to the present invention (first to third inventions), a cordless rotary polishing tool can be realized very easily by using an impact function limiting device for a cordless tool with an impact function. Thereby, the portability of the polishing tool is improved, and it becomes easy to cope with polishing work in a place where a power source cannot be secured or in a narrow place.
[0017]
Moreover, when applying this invention (1st-3rd invention) to a tool with an impact function, you may enable it to switch selectively a compression spring and a spacer (impact function restriction | limiting apparatus). Specifically, when the impact function is not limited, a compression spring is attached to the rotating shaft, and a tightening tool such as a driver or a wrench is attached to the output shaft. On the other hand, when the impact function is restricted, a spacer (impact function restriction device) is attached instead of the compression spring, and a processing tool such as a buff, a grindstone, or a drill is attached to the output shaft. Thus, by switching the presence / absence of the impact function according to the user's wishes, a single tool with an impact function can be used for various purposes.
In the present invention (first to third inventions), the drive motor may be an electric motor or an air motor.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The power tool according to the first embodiment of the present invention can switch the presence or absence of the impact function by the impact function restriction device.
[0019]
First, the configuration of the electric power tool 10 when the impact function is not limited is shown in FIGS. 1 and 2. As shown in FIG. 1, the power tool 10 is provided with an output shaft 13 in front of a body 12. The fastening tool 14 is fixed in the axial direction of the output shaft 13. A grip 15 extends below the body 12, and a rechargeable battery 16 is detachably attached to the bottom of the grip 15. When the switch 15a on the side of the grip 15 is pushed in, the driving force is transmitted to the output shaft 13 according to the pushing amount, and the fastening tool 14 rotates. In addition, although the driver is employ | adopted for the fastener 14 in FIG. 1, it can also replace | exchange for a wrench.
[0020]
As shown in FIG. 2, the body 12 is provided so that the rear case 12A and the front case 12B can be separated. Inside these cases, a drive mechanism for transmitting the drive force of the motor drive shaft 21 to the output shaft 13 is housed.
A disc-shaped gear holder 22 is provided at the tip of the motor drive shaft 21. As shown in FIG. 3, planetary gears 22 a and 22 b are attached to the gear holder 22, and the drive gear 21 a of the motor drive shaft 21 is engaged therebetween. An annular gear 12a that meshes with the planetary gears 22a and 22b outside the gear holder 22 is provided at a portion surrounding the gear holder 22 of the rear case 12A. When the drive gear 21a rotates, the planetary gears 22a and 22b mesh with the annular gear 12a and roll to rotate the gear holder 22 around the axis.
[0021]
A bearing 23 is provided behind the gear holder 22 (left direction in FIG. 2). The bearing 23 supports the end of the motor drive shaft 21 and prevents vibration of the drive gear 21a.
[0022]
A driven shaft 26 extends in front of the gear holder 22 (right direction in FIG. 2). A hammer 25 is attached to the tip of the driven shaft 26, and when the gear holder 22 rotates, the driven shaft 26 and the hammer 25 rotate together. On the front surface of the hammer 25, striking claws 25a and 25b facing each other in the radial direction are formed.
[0023]
An anvil 29 that rotates integrally with the output shaft 13 is housed in the front case 12B.
On the rear side of the anvil 29, locking claws 29a and 29b facing in the radial direction are formed. When the front case 12B is fixed to the rear case 12A, the hitting claws 25a and 25b of the hammer 25 and the locking claws 29a and 29b are brought into a position (engagement position).
[0024]
A cam mechanism is provided between the driven shaft 26 and the hammer 25. As shown in FIGS. 4 and 5, a pair of V-shaped cam grooves 26 d are formed on the outer peripheral surface of the driven shaft 26. On the other hand, as shown in FIG. 1, cam grooves 25 d that can be fitted to these steel balls B are provided on the inner peripheral surface of the hammer 25. Steel balls B are inserted into the cam grooves 25d and the cam grooves 26d, respectively.
When the hammer 25 is moved in the axial direction of the driven shaft 26, the steel ball B rolls along the cam groove 26d, and the hammer 25 rotates around the driven shaft 26. In other words, the hammer 25 reciprocates while rotating around the driven shaft 26.
[0025]
As shown in FIG. 2, a compression spring 27 is provided between the gear holder 22 and the hammer 25. The compression spring 27 pushes the hammer 25 forward in the axial direction (right direction in FIG. 2) from the front surface (right side surface in FIG. 2) of the gear holder 22, and keeps the striking claws 25a and 25b in engagement positions with the locking claws 29a and 28b. .
[0026]
In the configuration of FIG. 2, when the motor drive shaft 21 rotates, the gear holder 22, the driven shaft 26 and the hammer 25 integrally rotate in the reverse direction, and the hitting claws 25a and 25b engage the locking claws 13a and 13b. At the same time, the output shaft 13 is rotated. As a result, the driving force is transmitted to the fastener 14.
[0027]
The striking action of the electric power tool 10 is performed by the cam mechanism and the compression spring 27 described above. That is, when a certain load is applied from the fastener 14 to the output shaft 13, the hammer 25 stops rotating via the striking claws 25a and 25b and the locking claws 29a and 29b, and the driven shaft 26 is idle. Become. At this time, the hammer 25 is moved to the rear side (left side in FIG. 2) of the driven shaft 26 by the cam mechanism, and the compression spring 27 is pushed down. Next, when the hitting claws 25a and 25b are disengaged from the locking claws 29a and 29b, the hammer 25 is pushed by the compression spring 27 and pushed forward again. At this time, the hitting claws 25a and 25b hit the locking claws 29a and 29b, and this impact momentarily increases the fastening force of the fastening tool 14. And it becomes possible to tighten a screw etc. more firmly by repetition of such a striking action.
[0028]
As described above, in the configuration in which the electric tool 10 has the impact function, an impact force is generated in the rotation direction due to the load of the compression spring 27 when a large load is applied to the fastener 14 during work. For this reason, when the electric tool 10 is used with the fastener 14 replaced with a buff or a drill, there is a problem such as damage to the machining surface due to the striking force. With this configuration, the electric tool 10 can be easily polished. I can't do it. Therefore, in the present invention, the impact function of the electric tool 10 is restricted by the impact function restriction device, and the electric tool 10 can be used as a polishing tool or a punching tool.
[0029]
The configuration of the electric power tool 10 when the impact function is limited is shown in FIGS. As shown in FIG. 7, a processing tool 31 such as a buffing machine is attached to the output shaft 13 in place of the fastening tool 14. The processing tool 31 can be replaced with, for example, a sander or a drill.
[0030]
As shown in FIG. 8, in the electric power tool 10, an impact function restriction device 30 is set between the gear holder 22 and the hammer 25 instead of the compression spring 27. The impact function restriction device 30 includes split spacers 32 and 33 and a snap ring 35. Steel split spacers 32 and 33 are fixed to the driven shaft 26 by a snap ring 35.
[0031]
As shown in FIG. 9, the split spacers 32 and 33 are arranged such that a pair of arc-shaped spacers face each other with the driven shaft 26 interposed therebetween. A concave groove M extending with a constant width in the circumferential direction is formed on the outer peripheral surfaces of the split spacers 32 and 33, and a snap ring 35 is fitted into the concave groove M (see FIG. 8). Even if vibration or the like occurs in the split spacer 32, the snap ring 35 is held in the concave groove M, so that the split spacers 32 and 33 do not come off the driven shaft 26.
The thickness of the split spacers 32 and 33 is substantially the same as the maximum stroke of the hammer 25 from the gear holder 22. Accordingly, when the split spacers 32 and 33 are attached between the gear holder 22 and the hammer 25, the hammer 25 is fixed to the engagement position of the driven shaft 26.
[0032]
As shown in FIG. 10, the snap ring 35 is made of a C-shaped spring material, and is formed, for example, by punching a steel plate or the like into an arc shape. The inner diameter of the snap ring 35 is set to a size that substantially matches the outer diameter of the split spacers 32 and 33. Knob portions 35a and 35b are provided at the tip of the ring, and pin holes H for inserting tools such as pliers are formed in the knob portions 35a and 35b.
[0033]
When the impact function restriction device 30 is assembled to the electric tool 10, if the split spacers 32 and 33 are fixed to the driven shaft 26 before the hammer 25, the hammer 25 is moved to the rear of the driven shaft 26 (to the left in FIG. 8). It becomes impossible to secure an insertion port for inserting the steel ball B into the cam grooves 25d and 26d at the tip of the hammer 25 shown in FIG. That is, the split spacers 32 and 33 are obstructed, and the steel ball B cannot be inserted into the cam grooves 25d and 26d, and the rotational force of the driven shaft 26 cannot be transmitted to the output shaft 13.
Therefore, when the impact function restriction device 30 is assembled to the electric tool 10, the hammer 25 is attached to the driven shaft 26 in advance, and the steel ball B is inserted into the cam grooves 25d and 26d to keep the hammer 25 in the engaged position (see FIG. 11). Thereafter, as shown in FIG. 12, split spacers 32 and 33 are arranged on the driven shaft 26 and tightened with a snap ring 35.
By attaching the spacer spacers 32 and 33 to the driven shaft 26 in this way, the replacement work between the compression spring 27 and the impact function restriction device 30 can be performed easily and reliably.
[0034]
According to the impact limiting device 30, when a load exceeding a certain level is applied to the output shaft 13, the hammer 25 is moved from the engagement position of the driven shaft 26 by the split spacers 32 and 33 even if the load is transmitted to the hammer 25. Therefore, the driven shaft 26 does not rotate freely, and the engagement between the hammer 25 and the anvil 29 is not released. As a result, the impact function of the electric power tool 10 is limited, and it becomes difficult for wrinkles on the polished surface due to the striking force to occur, so that the polishing operation can be performed comfortably. Moreover, since the fixing strength of the split spacers 32 and 33 is large, the reliability is also high.
In addition, by returning the impact function restriction device 30 to the compression spring 27, the power tool 10 can be switched again to a driver, a wrench, or the like.
[0035]
Next, an impact function restriction device according to a second embodiment of the present invention is shown in FIGS. The impact function restriction device 40 according to the second embodiment employs bolts 45 and 46 and nuts 47 and 48 as fixing means for the split spacers 42 and 43.
[0036]
As shown in FIG. 13, the split spacers 42 and 43 are made of a pair of metal blocks, and a shaft hole is formed at a central portion where these blocks face each other. Through holes 42a and 42b are formed on both sides of the shaft hole.
When attaching the split spacers 42 and 43 to the driven shaft 26, as shown in FIG. 13B, the split spacers 42 and 43 are arranged on both sides of the driven shaft 26, and from one end of these through holes 42a and 42b. Bolts 45 and 46 are passed through and tightened to nuts 47 and 48 on the other end side.
[0037]
According to the impact function restriction device 40 according to the second embodiment, since the fixing means for the split spacers 42 and 43 are the bolts 45 and 46 and the nuts 47 and 48, the usability of the tool is good, and the impact function restriction device 40 Replacement work is relatively easy. This is advantageous when the presence / absence of the impact function is frequently switched.
[0038]
Although the said 1st Embodiment and 2nd Embodiment were demonstrated, embodiment by this invention is not restricted to these, A various change is possible. The shape of the slit spacer may be an ellipse or a polygon. In addition to the snap ring, bolts and nuts, clips, screws, etc. may be used as the means for fixing the split spacers. By using a magnet type spacer, the split spacers are attracted to each other by magnetic force. You may do it. Furthermore, in the case of adopting a cam mechanism in which a steel ball is not inserted from the front end of the hammer, an integral ring spacer can be used in place of the split spacers 42 and 43.
[0039]
【The invention's effect】
As described above, according to the impact function restriction device of the present invention, the following excellent effects can be obtained.
(A) The impact function of a tool with an impact function can be easily and reliably restricted.
(B) A tool with an impact function can be easily diverted to a polishing tool or a drilling tool.
(C) The switching operation with or without the impact function is easy and can be easily performed at the work site.
(D) By using a rechargeable battery, it is possible to provide a rotary polishing tool having excellent portability and workability.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a power tool according to a first embodiment of the present invention and showing a state before an impact function is restricted.
FIG. 2 is a cross-sectional view showing the power tool according to the first embodiment of the present invention and showing a state before the impact function is restricted.
FIG. 3 is a cross-sectional view taken along line III-III shown in FIG.
FIG. 4 is a side view showing a cam mechanism of the electric power tool according to the first embodiment and showing a state where a hammer is in an engagement position.
FIG. 5 is a side view showing the cam mechanism of the electric power tool according to the first embodiment and showing a state where the hammer is in a non-engagement position.
FIG. 6 is a plan view showing a cam mechanism of the electric power tool according to the first embodiment.
FIG. 7 is a perspective view showing the electric tool according to the first embodiment of the present invention and showing a state after the impact function is restricted.
FIG. 8 is a cross-sectional view showing the power tool according to the first embodiment of the present invention and showing a state after the impact function is restricted.
9A and 9B show a spacer spacer of the impact function restriction device according to the first embodiment of the present invention, in which FIG. 9A is a plan view showing a state before installation, and FIG. 9B is a plan view showing a state after installation; It is.
10A and 10B show a snap ring of the impact function restriction device according to the first embodiment of the present invention, where FIG. 10A is a plan view and FIG. 10B is a side view.
FIG. 11 is a side view for explaining a mounting method of the impact function restriction device according to the first embodiment of the present invention and showing a state before the impact function restriction device is installed.
FIG. 12 is a side view for explaining a mounting method of the impact function restriction device according to the first embodiment of the present invention and showing a state after the impact function restriction device is attached.
FIGS. 13A and 13B show a spacer spacer of an impact function restriction device according to a second embodiment of the present invention, in which FIG. 13A is a plan view showing a state before attachment, and FIG. 13B is a plan view showing a state after attachment; It is.
FIG. 14 is a side view of the mounting state of the impact function restriction device according to the second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Electric tool 12 Body 12A Rear case 12B Front case 13 Output shaft 14 Fastener 15 Grip 16 Rechargeable battery 21 Motor drive shaft 22 Gear holder 23 Bearing 25 Hammer 25a, 25b Impact claw 25d Cam groove 26 Drive shaft (rotation shaft)
26d Cam groove 27 Compression spring 29 Anvil 29a, 29b Locking claw 31 Buffing board 32, 33 Split spacer 35 Snap ring M Concave groove B Steel ball

Claims (5)

A rotating shaft driven by a drive motor;
A hammer attached to the rotating shaft by a cam mechanism and reciprocally mounted in the axial direction;
An anvil that engages the hammer and transmits the rotational force of the rotary shaft to the output shaft at the tip of the tool;
In a tool with an impact function provided with a compression spring attached to the rotating shaft and biasing the hammer toward the anvil side,
The impact is characterized in that a spacer is provided on the rotating shaft instead of the compression spring, and an axial position of the hammer is regulated by an end face of the spacer so that the hammer and the anvil are in an engagement position. Function restriction device. The impact function restriction device according to claim 1, wherein the spacer includes two or more split spacers, and the split spacers are fixed to the rotating shaft by a fixing unit. The impact function limiting device according to claim 2, wherein the fixing means for the split spacer is a snap ring, and a concave groove for receiving the snap ring is formed on an outer peripheral surface of the split spacer. A rechargeable battery type electric tool comprising the impact function limiting device according to claim 1. A rechargeable battery-type rotary polishing tool comprising the impact function restriction device according to claim 1.

Images