JPS61219583A - Impact tool - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an impact tool that uses electricity, air pressure, or the like as a power source to drive a hammer via an air spring.

[Background technology]

Conventionally, the special public interest tool was developed in 1974 as an impact tool using air spring metal.
There are those shown in Publication No. 15384, etc. As an impact tool that drives a hammer using the same principle as this, we proposed the one shown in Fig. 14.

This transmits the rotational motion of the motor 100 between a rotation transmission mechanism 101 consisting of a gear train and a crank mechanism 102 such as a crankshaft.
As a result, the reciprocating motion is transmitted to the piston 104 within the cylinder 103. A hammer 105 is slidably inserted into the cylinder 103, and a sealed air chamber is formed between the hammer 105 and the piston 104 within the cylinder 103. When the piston 104 reciprocates, this sealed air chamber repeats compression and expansion, and the hammer 105 reciprocates due to the pressure difference with the outside atmospheric pressure. Then, the hammer 105 hits the striker 106 and the bit 107
gives striking power to. Further, the rotation of the motor 100 is transmitted as rotation to the bit 107 via a rotation transmission path 108, separate from the reciprocating motion generating mechanism path of the hammer 105.

In such a blow generating mechanism, the piston 7104° and the hammer 105. The pressure state of the air chamber is as shown in FIG. That is, if the displacement of the piston 104 is stnωt, the displacement of the hammer 105 is i(ω[
1ψ). t is time and ψ is a phase shift difference.

The air pressure P is a function of the 17) distance %l between the piston 104 and the hammer 105, where Po = atmospheric pressure, cross-sectional area of the cylinder 14, v
o: initial air volume, γ: polytropic index. The distance l is 2(2)(ωi +-!!-) sinヱ.

In this way, the change in 1 air pressure P is gradual, and the hammer 10
Since the movement of the 5 was gradual, there was a drawback that a strong hitting force could not be obtained.

[Purpose of the invention]

An object of the present invention is to provide an impact tool that can provide a strong impact force.

[Disclosure of the invention]

The impact tool of the present invention includes a cylinder housing a piston that is reciprocated by a drive device, and an intermediate impact transmission member that is fitted into the cylinder and driven reciprocally through air pressure by the reciprocating movement of the piston. a locking member that is provided in the cylinder at a midway position in the reciprocating stroke of the hammer and locks the hammer at a predetermined air pressure or less against the air pressure by a pressing force of a pressing body; It is equipped with the following.

According to this configuration, even if the piston moves, the hammer is locked by the locking member until the air pressure in the cylinder increases. When the air pressure increases to a predetermined pressure, it overcomes the pressing force of the pressing member that presses the locking member, and the hammer is disengaged from the locking member, and the air pressure that has been accumulated moves all at once to strike the hammer. Therefore, strong hitting power can be obtained.

Embodiment An embodiment of the present invention is shown in FIGS. 1 to 13. In the figure, reference numeral 1 denotes a housing, in which a handle 2 is integrally formed at the rear and a motor 4 serving as a driving source for rotation and impact is accommodated.

Reference numeral 5 indicates a storage battery as a power source, 8 a switch as a main switch, and 8' a switch operator. The rotation of the motor 4 is transmitted from a pinion 9 attached to its output shaft to a gear 11 at one end of the intermediate shaft 10. This rotation, in one path, is transmitted to the cylinder 14 by a gear 13 and a binio/12 attached to the other end of the intermediate shaft 10. The cylinder 14 is connected to the gearbox 1 with bearings 15 and 16.
7 and is rotatably supported. A cylindrical intermediate impact transmission member 44 is fitted to the distal end side of the cylinder 14, and a stop key 21' is inserted into a key groove provided in the cylinder 14 and the spindle 20, so that the rotation of the cylinder 14 is controlled by the spindle 20. and bit 21. The bit 21 and the spindle 20 are engaged with each other by a transmission key 22. 26 is a presser nut. spindle 20
A chuck sleeve 23, a bit cover 24, and a dustproof wall ring 25 are provided.

On the other hand, the rotation of the intermediate shaft 10 is transmitted to the movable clutch member 28 through engagement between an inpoliate spline convex portion provided on the outer periphery of the intermediate shaft 10 and an involute spline recess provided in the movable clutch member 28. A dog clutch pawl 28a is formed at the end of the movable clutch member 28 on the side of the bevel gear 30, and a clutch pawl is also formed on the bevel gear 30 so as to mesh with the clutch pawl 28a. 31 is a coil spring, and 32 is a disc spring. As shown in FIG. 1, when the clutch pawl 28a is engaged, the rotation of the intermediate shaft passes through the bevel gear 30.33 to the eccentric shaft 35.36.
The piston 38 provided at the tip of the connecting rod 37 reciprocates within the cylinder 14. 38' is a drive bin. Similarly, a hammer 39 is slidably provided within the cylinder 14 for striking via an intermediate striking transmission member 44. The intermediate impact transmission member 44 is provided within the spindle 20 so as to be freely movable in the axial direction, and a sealing member 45 such as an O-ring is fitted into a groove formed on the outer periphery of the intermediate impact transmission member 44 .

The cylinder 14 has a large diameter portion 50 formed at its front end. Further, the cylinder 14 is provided with a plurality of air holes 18 near the front end, and a plurality of long holes 51 extending in the axial direction of the cylinder 14 are provided near the air holes 18 .

The elongated hole 51 movably accommodates a spherical locking member 52, and also serves as an intake and exhaust hole. The locking member 52 is pressed by a spring body 53 serving as a pressing body, engages with a groove 54 on the outer periphery of the hammer 39, and temporarily stops the movement of the hammer 39.

Note that instead of the spring body 53, an electromagnet, a permanent magnet, or the like may be used as the pressing body. No./739 has a seal member 55 fitted on the outer periphery. As shown in FIGS. 8 and 9, the spring body 53 is provided with a ring-shaped cut and raised spring piece 53a, and is rotatably fitted onto the cylinder 14.

The spring body 53 integrally fixes a spring pressure adjustment lever 57 protruding from a lever hole 56 of the housing 1. The spring body 53 presses down the locking member 52 only when the locking member 52 is in the position on the pit 21 side within the elongated hole 51. When the locking member 52 moves inside the elongated hole 51 toward the piston 38, it comes off from the spring body 53, but at this removed position, the hook-shaped locking member regulating body 58 is fitted onto the cylinder 14. .

The locking member regulating body 58 is configured so that the locking member 52 is connected to the cylinder 140.
This prevents it from escaping in the radial direction. A ring-shaped spring retainer 59 is provided on the outer periphery of the locking member regulating body 58 and the spring body 53.

The storage section for the battery 5 will be explained. A battery storage section 60 is formed in the housing 1, and a battery locking device 62 for holding the battery 5 with a battery holding piece 61 is provided in the battery storage section 60. 63 is a battery terminal. The battery fixing piece 61 is
The fixing piece housing hole 64 provided in the housing 1 is removably inserted into the fixing piece housing hole 64, and is biased to be pulled in by a third spring 65 made of a torsion coil spring. The fixed piece 61 has an engagement groove 61a, into which the tip of the fixed piece presser rod 66 is engaged. The fixed piece presser bar 66 is connected to a second crankshaft 67 through a first rotating cam 68 and a second rotating cam 69, and the second crankshaft 67 is connected to the first crankshaft 70 by a pin.

The first crankshaft 70 is rotatable around a crankshaft fulcrum 71, and has an operator 72 connected to one end thereof. 73 is a first spring, and 74 is a second spring. Further, 75 is a battery locking device storage space formed in the housing 1. As shown in FIG. 12, the first rotating cam 68 has a long protrusion 68a and a short protrusion 68b, and the second rotating cam 69 has a deep groove 69.
a and a shallow groove 69b. These protrusions 68a.

Due to the difference in the depth of engagement between the grooves 68b and the grooves 69a and 69b, the connecting body between the second crankshaft 67 and the fixed piece presser rod 66 has two states with different lengths.

The handle 2 and switch 8 will be explained. As shown in FIGS. 2 and 3, a handle recess 72 is formed at the rear end of the housing 1, and the housing 1
A groove 73 is formed between the rear end and the tip of the pit. The length of the knife handle concave groove 73 is longer than the standard human thumb length, and the inner surface of the groove is finished with a curved surface so that the operator does not feel any discomfort when he or she cleans his or her hand. No-endoru concave groove 73
are provided on the left and right sides of the nozzle, and both have the same groove length and shape. 75 is a forward/reverse changeover switch. As shown in FIG. 1, the main switch 8 is located at the intersection of the nose housing 1 and the handle 2.

The rotation of the operating motor 4 is controlled by the pinion 9. Gear 11 to intermediate shaft 1
0 and is transmitted to the cylinder 14 by the pinion 12 and gear 13. Therefore, the bit 21 rotates together with the cylinder 14. Further, the rotation of the intermediate shaft 10 is transmitted to the eccentric shaft 35.36 via the clutch member 28 and the bevel gear 30.33, and the piston 38 provided on the connecting rod 37 reciprocates within the cylinder 14. Therefore, the air in the cylinder 14 is repeatedly compressed and expanded, and the hammer 39 strikes the intermediate impact transmission body 44, giving the bit 21 reciprocating motion. The clutch member 28 is moved by the switching lever 81 (
When removed from the bevel gear 30 in FIG. 2), the drive of the motor 4 is not transmitted to the piston 38, and the bit 21 only rotates. Therefore, depending on the material to be drilled, it is possible to select between drilling by rotation only and rotational impact.

I will explain the blow in more detail. The piston 38 reciprocates within the cylinder 14, and is also slidably provided within the cylinder 14).
The piston 3B forms an airtight air chamber with the piston 3B.
The reciprocating motion compresses or expands the air in this air chamber, creating a pressure difference between this air and atmospheric pressure, and...
A force that causes the cylinder 14 to reciprocate is applied to the cylinder 39 . Here, in this invention, as shown in FIG. The hammer 39 is engaged with a groove 54 provided in the groove 54 to lock the hammer 39. Now, when the piston 38 starts reciprocating toward the hammer 39 side and compresses the air, and reaches a predetermined pressure, the force that moves the hammer 39 toward the bit 21 locks the hammer 39. The hammer 39 overcomes the spring force of the spring body 53 that presses the locking member 52, and the hammer 39 presses the locking member 5.
2 and hits the intermediate impact transmission member 44, transmitting the impact force to the bit 21 (FIG. 6). The ball 39 that hit the intermediate impact transmission member 44 is
4 and the air chamber pressure and atmospheric pressure due to air dilution due to the expansion of the air chamber during the return process of the piston 39 to the motor side. ) and the force due to the pressure difference between the piston 39 and the piston 39 side. At this time, the force generated in the hammer 39 pushes up the locking member 52 against the spring force that presses the locking member 52, and when the locking member 52 engages with the groove 54 provided in the hammer 39, the hammer 39 stops reciprocating,
It stops at that position. In order to ensure the locking operation, a protrusion (not shown) may be provided on the inner diameter of the cylinder 14 outside the movement range of the piston 38 to lock the hammer 39.

Here, the hole provided in the cylinder 14 for arranging the locking member 52 is an elongated hole 51 that is long in the axial direction of the cylinder 14, and the movement of the locking member 52 in the cylinder radial direction is controlled by the bit 21.
It is elastically movable on the side by a spring body 53, and is not movable on the piston 38 side by a locking member regulating body 58. This is because the elongated hole 51 is simply a substantially perfect circle, and if the circular hole is closed by the locking member 52 pressed against the spring body 53, the spring of the spring body 53 during the compression process of the air chamber. When the locking member 52 is pushed up against the force, air leaks out, and during the expansion process of the air chamber, the locking member 52 closes the hole and no air enters, and as the piston 38 reciprocates repeatedly, the air in the air chamber is The air becomes diluted to atmospheric pressure, and the volume of the air chamber becomes smaller than it was initially, making it impossible to generate a high impact force with a given piston stroke. For this reason, the piston 38 and the hammer 39
It is necessary to provide a second air hole for adjusting the amount of air in the air chamber composed of 52 to the intermediate impact transmission member 44 side, and the elongated hole 5
1, the locking member 52 is pushed up against the spring force of the spring body 53, and the locking member 52 is pushed up against the hammer 39.
The hammer 39 is removed from the groove 54 of the intermediate impact transmission member 4.
Hit 4. At this time, a part of the long hole 51 (locking member 52
The part that is not fitted can serve as a discharge port for compressed air.

Further, when the hammer 39 that has struck the intermediate impact transmission member 44 returns to the motor 4 side in conjunction with the movement of the piston 38, the discharge port becomes an air inflow port 6, and the spring body 5
After the locking member 52 is pushed up against the spring force 3 and the locking member 52 fits into the groove 54 provided in the hammer 39, both the hammer 39 and the locking member 52 move toward the motor 4 side. That is, the locking member 52 is fitted into the elongated hole 51 on the piston side, and is regulated here by the locking member regulating body 58 so that the cylinder 14
0 It becomes impossible to move outward in the radial direction (Fig. 4).

This is to restrict the movement of the locking member 52 and ensure that the knob 739 is positioned higher.

As described above, in this embodiment, the hammer 39 is held until a certain compressed air pressure is reached that resists the spring force of the spring body 53, and the energy stored up to that point is used to energize the hammer 39. A large kinetic energy can be applied to the hammer 39, and a large striking force can be transmitted to the bit 21. Therefore, drilling work in concrete etc. can be carried out easily and efficiently. ) Also, the P1 motor 4, which requires less driving power to obtain the same high impact force, can be made smaller, leading to cost reduction and improved usability due to the lighter weight of the impact tool. In addition, Fig. 11 tlj
: shows the relationship between the displacement of the piston 38 and the nozzle 39 and the pressure in the air chamber. As you can see from the same figure, hammer 3
The rise in the batting time of 9 is sharp, so no.
The speed of the hammer 39 is high, and the energy of the hammer 39 is large.

The locking force of the hammer 39 by the locking member 52 can be adjusted by rotating the spring pressure adjustment lever 57 shown in FIG. 8 within the rotatable range R. That is, when the spring pressure adjusting lever 57 is rotated, the length between the bending point of the cut and raised spring piece 53a and the contact point of the locking member 52 (FIG. 9) changes, and the spring pressure changes. In this way, since the spring force is variable, the impact force can be adjusted depending on the target member. Therefore, drilling of the target member can be performed neatly. for example,
If a large impact force is used when drilling a hole in a brittle conocrete member, the member will chip at the end of the member, and the amount of plowing at the start of drilling will spread to the vicinity of the required hole, making it impossible to finish a clean hole. Such problems can be solved. In addition, with battery-powered tools, the energy can be effectively utilized for work.

Furthermore, in this embodiment, the piston 38 prevents the locking member 52 that engages with the elongated hole 51 provided in the cylinder 14 from moving outward in the cylinder radial direction as described above. The nozzle 39 can be locked securely and easily.

In addition, the elongated hole 51 is used for the following purpose.

That is, the pressure in the air chamber between the piston 38 and the hammer 39 has a large pressure difference from the atmospheric pressure during the compression process, and air leaks from the seal between the piston 38, the hammer 39, and the cylinder 14. During the stroke, the pressure difference between the air pressure in the air chamber and the atmospheric pressure is small, so the amount of air flowing in from the seal portion is considerably smaller than the amount of leakage. Therefore, the volume of the air chamber decreases as the operating time increases, and eventually the piston/38 will adhere to the hammer 39. In order to prevent this, air is taken in and exhausted through the elongated hole 51.

Next, prevention of blank firing, etc. will be explained. When the bit 21 is mounted and pressed against an object, the intermediate impact transmission member 44 is at a predetermined position, and the intermediate impact transmission member 44 is struck by the hammer 39 and the impact force is applied to the bit 21. Given. At this time, the air chamber formed in the cylinder 14 by the intermediate impact transmission member 44 and the hammer 39 has an air hole 1.
Because there are 8 air inlets and outlets, the impact force is transmitted without attenuation. During blank firing, the intermediate impact transmission member 44 moves from the inside of the cylinder 14 to the spindle 2 during the first blank firing.
Move within 0. Also, since there is no resistance for the hammer 39, it is thrown to the back of the cylinder 14, and the cylinder 14
The sealing member 55 attached to the hammer 39 at the large-diameter portion 50 increases in size in the radial outward direction and is supported (FIG. 7). At this time, the air flowing due to the reciprocating motion of the piston 38 is taken in and exhausted from the air hole 18, so the pressure inside the air chamber does not create a large pressure difference compared to the atmospheric pressure...739
is supported without being disengaged from the cylinder 14. Note that the large diameter portion 50 of the cylinder 14 may be formed by providing four portions in a portion. Furthermore, although the sealing member 55 is shown as an O-ring, it may be provided with a notch like a piston ring to have spring properties in the radial direction.

In this way, the seal member 55 can also serve as a structure for preventing dry firing, resulting in a simple nest. In addition, only the piston 38 reciprocates during idle firing, reducing power consumption. This is particularly advantageous for rechargeable battery type devices. Furthermore, since dry firing can be prevented reliably and without applying any load such as vibration to the mechanism, the life of the main body is improved.

The operation for attaching and detaching the battery 5 will be explained. When the battery 5 is removed, unlike the state shown in FIG.
and the second rotating cam 69 are in a connected state with a short length. That is, the long protrusion 68a of the first rotating cam 68 and the short groove 69a of the second rotating cam 69 are in a state of engagement. In this state, when the battery 5 is inserted from the right side, the battery 5 pushes the operator 72, and the force is transmitted to the first crankshaft 70, which rotates about the crankshaft fulcrum 71, and the second crankshaft 67 It is transmitted to Second crankshaft 67
The force transmitted pushes the first rotating cam 68, further pushes the second rotating cam 69, and pushes the fixed piece presser bar 66. The tip of the fixed piece presser rod 66 is tapered, and the fixed piece presser rod 6
The force was transmitted to the housing 1 by the force of the third spring 65.
The battery fixing piece 61f is transmitted from the tapered surface of the fixing piece presser rod 66 to the groove 61a of the battery fixing piece 61 that was housed in the battery fixing piece 61f.
: Push up. In this state, the first rotating cam 68 and the second rotating cam 69 are short in length, but the second spring 74, which had been compressed in this state, tries to return to its original state, and the fixed piece presser bar 66 is pushed up, but the second rotary cam 69 is rotated by the torsional force of the third spring 65 acting at that time, changing the state of meshing with the first rotary cam 68, and becoming longer in length.

The first rotating cam 68 and the second rotating cam 6 in a long state
FIG. 1 shows the fixed state of the battery at the meshing state pressure of 9.

Next, when removing the battery 5, push the battery 5 from the right in the state shown in Fig.
The engagement of the rotating cam 69 is made short, and the battery 5
Make it removable. Through such operations, the battery 5 can be attached and detached with one touch.

A method for holding the housing 1 during drilling will be explained.

When drilling a hole in the object to be drilled, the operator presses the base of the thumb and index finger against the handle recess 72 at the rear end of the housing 1, and inserts the thumb and index finger into the handle recess 73.
Hold the housing 1. Using the remaining fingers other than the thumb and forefinger, grasp the switch 8 located at the offset position between the housing 1 and the handle 2. With the other hand - Ujifugu 1
supports and performs drilling of the object to be drilled. In this way, the handle recess 72 into which the operator inserts his/her fingers to hold the housing 1 and the handle recess groove 73 are located at an intermediate position between the housing 1 and the handle 2 on the bit axis on the side opposite to the handle 2. Therefore, there is an advantage that operability with the switch 8 is good and work efficiency is high. When drilling a hole, the operator's hand holding the housing 1 is close to the bit axis, so the bit 21 is pushed with a strong force, and furthermore, the moment applied to the housing 1 due to the reaction force from the bit 21 is prevented. effective.

FIG. 13 shows the state in which the dust cup 80f is used. The dust cup 80 is made of rubber or the like and is formed into a cylindrical shape, and is inserted into the dust cup mounting groove 82 of the housing 1.
It is attached elastically and removably. dust cup 8
0 has a thin wall in the center, and as the drilling progresses,
It deforms elastically when pressed by the object to be drilled, and stores chips from the drilling. In this way, one dust cup 80 can prevent chips from scattering, making it easy and safe to perform upward drilling operations. When the dust cup 80 is not used, the dust cup 80 is turned over at the thin center portion and placed over the housing 1 (as shown in FIG. 2). This makes it easy to work without any pressure in the way, and prevents the dust cup 80 from being lost.

Further, this dust cup 80 has a simple structure and is inexpensive.

In the above embodiment, the electric motor 4 is used as the drive device.
However, in addition to this, a vane motor driven by fluid pressure such as liquid or air, or a drive device that reciprocates the piston 38 by intermittently supplying liquid can be used.

〔Effect of the invention〕

The impact tool of this invention temporarily holds the hammer with a locking member, and when the air pressure increases, the locking member becomes unlatched against this holding force, and the previously accumulated air pressure suddenly releases the hammer. Because it moves, it has the effect of providing a strong striking force.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a rear view thereof, FIGS. 4 to 7 are illustrations of its operation, and FIG. 8 is a similar diagram. 9 is a sectional view of the housing at the location where the locking member is arranged, FIG. 9 is a sectional view showing the relationship between the locking member and the spring body, FIG. 10 is a partial perspective view of the spring body, and FIG. 11 is the same. An explanatory diagram of the relationship between the displacement of the piston and the air pressure,
Fig. 12 is a perspective view of the cam of the battery locking device, Fig. 13 is an explanatory diagram of the usage state using the dust cup, Fig. 14 is a sectional view of the conventional example, and Fig. 15 is an explanation of its operation. It is a diagram. 1... Housing, 2... Handle, 4... Motor, 5... Battery, 10... Intermediate shaft, 13... Gear, 17... Gear box, 18... Air hole , 20・
...Spindle, 21...Bit, 35.36...
Eccentric shaft, 37... Stove)', 38... Piston, 39... Hammer, 44... Intermediate impact transmission member, 5
o... Large diameter portion, 51... Long hole, 52... Locking member, 53... Spring body (pressing body), 54... Groove, 55...
... Seal member, 58 ... Locking member regulating body, 80 ...
・Dust cup

Claims (6)

[Claims] (1) A cylinder that accommodates a piston that reciprocates by a drive device, and a hammer that is fitted into the cylinder and is driven reciprocally through air pressure by the reciprocating motion of the piston to strike the bit via an intermediate impact transmission member; An impact tool comprising: a locking member that is provided in the cylinder at a midway position in the reciprocating stroke of the hammer and locks the hammer at a predetermined air pressure or less against the air pressure by a pressing force of a pressing body. (2) The impact tool according to claim (1), wherein the pressing force of the pressing body of the locking member is variable. (3) The impact tool according to claim 1, wherein the cylinder is provided with an elongated hole for intake and exhaust along the axial direction, and the locking member is movably disposed within the elongated hole. (4) The locking member is supported so as to be able to escape radially outward of the cylinder by the pressing body only at a bit side position in the elongated hole, and is detached from the spring body at a piston side position. The impact tool according to claim 3, further comprising a locking member regulating body that prevents the locking member from escaping outward in the radial direction of the cylinder at a position on the piston side. (5) Claim No. 1 (2012) in which the pressing body is a spring body.
Impact tool described in section 1). (6) Claim No. 1 in which the pressing body is a magnet.
Impact tools listed in ).