JPH042781Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a hand-type reciprocating tool driven by compressed air.

<Background of the Prior Art> Hand-held cutting tools and grinding tools that use electricity as a driving source have been proposed, but they have structural difficulties and are not fully satisfactory in terms of workability. For example, in the case of a saw, it is easier to use and work better if you can use it with one hand, but the tool is heavy and
If it is too large, the work will tend to become unstable, and it will be extremely difficult to continue working for a long time, or if you use it in a narrow space, it will put a lot of strain on your hand and require high precision. I was unable to concentrate on the work being done. Therefore, the need to reduce the weight and size of this type of tool has been an extremely important problem.

In addition to the saws mentioned above, hand-type tools are required to meet various conditions such as low vibration and noise, no scattering of chips, and easy replacement of blades and polishing tools. Conventional tools have both advantages and disadvantages, and none can satisfy all of them.

<Purpose of the invention> The purpose of the invention is to reduce the weight and size of handy-type cutting tools and grinding tools such as saws, and to also make them effective in preventing vibration and noise.

<Configuration of the invention> In order to achieve the above object, the tool of the invention has the following features:
The drive source is a free piston that reciprocates using compressed air, and a cutting tool or a grinding tool is provided in front of a second free piston whose axis is aligned with the second free piston, and these pistons are The introduction passage for the compressed air that reciprocates the compressed air and the exhaust passage for the used air after use are provided in the optimum position of the cylinder, and the reciprocating movement of the first and second pistons and the instantaneous force generated between the two pistons allow the cutting tools and The grinding tool is characterized by a high speed and stable reciprocating motion.

<Example> Figures 1 to 6 show an example of a saw in which the present invention is implemented, and this saw is constructed as follows.

1 is a cylindrical housing provided with a grip portion on its outer surface; 2 is a cylinder provided in the axial direction within the cylinder of the housing 1; the front and rear of the housing 1 are closed by a front end member 3 and a rear end member 4, respectively.

A first free piston (hereinafter referred to as the "first piston") 5 is housed in the rear part of the cylinder 2, and a second free piston (hereinafter referred to as the "second piston") 6 is placed in the cylinder with its axial direction aligned with the first piston 5. A driving shaft 7 is provided at the center of the second piston 6 so as to protrude from the front end member 3 of the housing 1 in the front direction. A saw blade 8 is detachably attached to the tip of the shaft 7.

Since the housing 1 becomes a grip part, it has an outer diameter as slim as possible, and compressed air is introduced into the cylinder 2 through the inner wall surface that comes into contact with the outer periphery of the cylinder 2, as shown in FIGS. 4A and B. Groove 9 for
9 and grooves 10 for discharging the compressed air that has passed through the cylinder 2 are formed in the axial direction, and the air introduction passage L is formed by the air guide/exhaust grooves 9 and 10 surrounded by the outer periphery of the cylinder 2. ₁ and form an air exhaust passage L ₂ . In this example, the air introduction passage L ₁ is provided on the left and right sides of the lower side, and the air exhaust passage L ₂ is provided on the left and right sides of the lower side.
are widely spaced on the upper left and right sides and on the top.

In order to introduce compressed air into the cylinder 2 from the air introduction passage _L1 , the cylinder 2 installed in the housing 1 has a portion that coincides with the air introduction grooves 9, 9, and the first Air introduction holes 11a and 11b are provided at substantially central portions of the outer peripheries of the piston 5 and the second piston 6,
Further, in order to discharge the compressed air that has passed through the cylinder 2 after acting into the air discharge passage L ₂ , the first piston 5 and the second piston 6 are provided at a portion that coincides with the air discharge groove 10 . A total of eight air exhaust holes 12a to 12d are provided in two rows from the rear to the front at the front and rear edges of the outer periphery.

Further, the rear end member 4 that closes the rear end of the housing 1 is connected to the air introduction grooves 9, 9 of the housing 1.
and a through hole 1 in a portion corresponding to the air exhaust groove 10...
It is fixed by fixing screws 14 (only one at the four corners is shown in the drawing) with a gasket 13 having 3a and 13b interposed therebetween. As shown in FIGS. 3 and 6, this rear end member 4 has an air introduction passage L _{' 1} communicating with the air introduction passage L ₁ and an air discharge passage communicating with the air exhaust passage L ₂ in its length direction. Passage L′ ₂
The air introduction passage L' ₁ is opened and closed in the middle by a valve mechanism provided in the rear end member 4.
This valve mechanism V includes an on-off valve 15 that closes the air introduction passage L' ₁ , and a valve rod 1 to which the on-off valve 15 is fixed and whose lower end protrudes toward the bottom side of the rear end member 4.
6, a compression spring 17 that presses the opening/closing valve 15 in the closing direction, a valve mounting cylinder 19 that is installed in the valve storage hole 18 and presses and holds the compression spring 17, and this cylinder 19 and the storage hole 18. It consists of an O-ring 20 interposed between the cylindrical body 19, a spacer 21 for flow pressure adjustment, and a retaining ring 22 that fits into a groove on the inner circumferential surface of the storage hole 18 to fix the cylindrical body 19. Further, on the bottom side of the rear end member 4, there is a valve operating lever (hereinafter referred to as the operating lever) 23 that is operated by the operator at the time of startup, and the inner surface thereof is opposed to the protruding lower end of the valve rod 16 of the valve mechanism V. 24, and the free end side of the lever extends obliquely to the bottom side of the housing 1. Furthermore, at the rear end of this rear end member 4, a central hose 2 is attached.
6a and an outer hose 26b are connected. Reference numeral 25 denotes a pipe joint detachably connected to the air introduction passage L' ₁ provided at the center of the rear end member 4. The end of the center side hose 26a is connected to this pipe joint, and the end of the outer hose 26b is connected to the pipe joint 25. is fixed to the outer peripheral edge of the rear end member 4 by a stop ring 27, and communicates with the air discharge passage L' ₂ . In addition,
Inside the outer hose 26b, a tape-like material 28 made of a porous elastic material is spirally wound around the outer periphery of the center hose 26a in order to absorb exhaust noise.

On the other hand, two circumferential grooves 29 and 30 having a width wider than the diameter of the air introduction hole 11a formed in the cylinder 2 are provided on the outer periphery of the first piston 5 at the approximate center thereof, which is housed in the cylinder 2. , the circumferential groove 29 on the front side of the piston communicates with the rear of the cylinder chamber R through the communication passage _L3 formed in the longitudinal direction in the first piston 5, and the circumferential groove 30 on the rear side also communicates with the rear side of the cylinder chamber R It communicates with the central portion of the cylinder chamber R through a communication passage _L4 formed in the longitudinal direction within the cylinder chamber R. Therefore, when compressed air is supplied toward the first piston 5, it depends on whether the circumferential grooves 29, 30 of the piston 5 are located forward or backward relative to the air introduction hole 11a. When the air introduction hole 11a opens into the front circumferential groove 29, compressed air is supplied to the rear of the cylinder chamber R through the communication passage _L3 , so the first piston 5 moves forward instantly. , conversely, the air introduction hole 11
When a opens into the rear circumferential groove 30, compressed air is supplied to the center of the cylinder chamber R through the communication passage _L4 , so that the first piston 5 instantly retreats rearward. In either case, after moving the required stroke, air introduction hole 1
1a and the opening circumferential groove are exchanged, so the first piston 5 that has moved forward changes to a backward position, and the first piston 5 that has moved backward changes to a forward position, and the reciprocating movement of the first piston 5 is repeated. Due to the reciprocating movement of the first piston 5, air exhaust holes 12 are formed in the cylinder 2 at positions corresponding to the front and rear edges of the piston 5.
Since a, 12a and 12b, 12b are opened and closed alternately, the compressed air within the cylinder chamber R is smoothly exhausted. Further, on the outer periphery of the approximately central portion of the second piston 6 housed in the cylinder 2,
Two circumferential grooves 31 and 32 of appropriate width are provided, and the front circumferential groove 31 communicates with the center of the cylinder chamber R through a communication passage _L5 formed in the length direction within the second piston 6. Further, the rear circumferential groove 32 is also a communication passage formed in the length direction inside the second piston 6.
It communicates with the front of the cylinder chamber R through _L6 . Therefore, when supplying compressed air toward the second piston, the circumferential grooves 31 and 32 of the piston are connected to the air introduction hole 1 of the cylinder 2.
1b, depending on whether it is located in the front or the rear, that is, when the air introduction hole 11b opens into the circumferential groove 31 on the front side, as in the case of the first piston 5, the communication passage Since compressed air is supplied to the center of the cylinder chamber R through _L5 , the second
The piston 6 moves forward instantly, and conversely, when the air introduction hole 11b opens into the rear circumferential groove 32, compressed air is supplied to the front of the cylinder chamber R through the communication passage _L6 . Therefore, the second piston 6 instantly retreats rearward, and in either case, when the second piston 6 moves by the required stroke, the air introduction hole 11b and the opening circumferential groove change places.
The second piston 6 that moved forward turns backward, and the second piston 6 that moved backward turns forward, and the second piston 6 moves backward.
The reciprocating motion is repeated. Due to this reciprocating movement of the second piston 6, the air exhaust holes 1 provided in the cylinder 2 corresponding to the front and rear edges of the piston 6 are
Since 2c, 12c and 12d, 12d are opened and closed alternately, the compressed air within the cylinder chamber R is smoothly discharged.

The drive shaft 7 provided at the axial center of the second piston 6 that reciprocates as described above connects the rear small-diameter male threaded portion 7a to the second piston 6.
is inserted from the front into the center hole of the second piston 6, and is fixed from the rear of the second piston 6 with a hexagonal socket set screw 33,
Furthermore, a sleeve bearing 34, a cap seal 35, and an oil seal 36 for preventing wear are fitted into the penetrating portion of the tip member 3 of the housing 1. Further, the tip member 3 supporting the shaft 7
is a fixing screw 37 (in the drawing,
A positioning pin 38 is installed in the inner part of the tip member 3 that corresponds to the top of the housing 1, and when the cylinder 2 is assembled, It is designed to fit into a positioning notch 2a provided at the top of the tip.

Furthermore, an extending portion 3a extending horizontally is formed on the upper side of the front surface of the tip member 3, and this extending portion 3a
A guide holder 39 having slide grooves 39a, 39a opened downward and symmetrically is fixed to the lower surface of the guide holder 39 with fixing screws 40, 40. This guide holder 39 has two divided parts 41a and 4 at its tip.
1a, and a plate-shaped guide portion 41b of a cylindrical chuck member 41 fixed to the tip of the shaft 7 by a hexagonal hole fixing bolt 42 is slidably fitted. Two divided parts 41a, 4 of this chuck member 41
A tightening band 43 is attached to the outer periphery of the saw blade 1a, and when the two bent butt ends of this band 43 are tightened with the tightening screw 44, the base 8a of the saw blade 8 described above is separated into the two divided portions 41a, 41a. strongly held in between. At this time, the root portion 8b of the saw blade 8 is stored in the positioning hole 7b at the tip of the shaft 7, and
It hits the deep part of b and is accurately positioned. Further, a base portion of a supporter 45 is attached to the forward extending portion 3a of the tip member 3 to protect the saw blade 8 from the left and right directions, which is made by folding a metal wire in half and bending the tip into a downward inverted L-shape. Further, the outer periphery of this forward extending portion 3a is covered with a highly elastic rubber cap 46 that covers the entire periphery of the portion 3a.

Next, the operation of the above embodiment will be explained.

The operator connects the central hose 26a of the double hose 26 to an air compressor (not shown), holds the central grip of the housing 1 with one hand, and presses the operating lever 23 with four fingers excluding the thumb. The valve rod 16 is pushed up, the on-off valve 15 of the valve mechanism V opens, and the compressed air flows through the air introduction passage L' ₁
and the air introduction passage in the outer periphery of the cylinder 2 and the inside of the housing 1 through the through holes 13a, 13a of the packing 13.
_L1 , the air introduction hole 11a of the cylinder 2,
11b is reached. These air introduction holes 11a, 11b
depends on the positions of the first piston 5 and the second piston 6 at the time of startup, but as described above, the circumferential groove 29 or 30 on the outer periphery of the first piston 5 or the circumferential groove on the outer periphery of the second piston 6. Since compressed air is alternately supplied to 31 or 32, both pistons 5,
6 reciprocates at high speed. That is, in the case of the first piston 5, when the air introduction hole 11a and the circumferential groove 29 match, the compressed air enters the cylinder chamber R via the communication passage _L3 and advances the piston.
When the air introduction hole 11a and the circumferential groove 30 match, the compressed air passes through the communication passage _L4 and enters the cylinder chamber R.
and move the piston backward. In addition, in the case of the second piston 6, the air introduction hole 11b and the circumferential groove 3
1, the compressed air flows through the communication passage L ₅
When the air introduction hole 11b and the circumferential groove 32 match, the compressed air enters the cylinder chamber R through the communication passage _L6 and moves the piston backward. The first piston 5 moves forward, and the second piston moves back to increase the pressure of the compressed air in the cylinder chamber R between the pistons 5 and 6, causing the second piston ₆ to move forward at an instantaneous moment. Compressed air joins this movement and forces the piston forward. Further, when the second piston 6 moves forward, the second piston 6 and the front end member 3
Because the pressure of the compressed air between the second piston 6 and the second piston 6 is increased, the second piston 6 instantaneously moves backward, and the compressed air from the communication passage _L6 joins this movement to force the second piston 6 to retreat violently. In this way, the first and second
The compressed air acting on the pistons 5 and 6 flows into the cylinder chamber R in relation to the strokes of the pistons 5 and 6.
Air exhaust holes 12a or 12 that open alternately in
b, or 12c or 12d to reach the outer periphery of the cylinder 2, and the air exhaust passage in the housing 1
Guided by L ₂ , through hole 13b of packing 13...
The air is then exhausted to the outer hose 26b of the double hose 26 via the air exhaust passage L' ₂ .

The action is a relative movement between the first piston 5 and the second piston, and due to this action, the first and second pistons move back and forth relatively to activate the saw blade 8.
This effect will be explained in more detail below.

When the first piston 5 moves forward, the compressed air acting thereon enters the rear cylinder chamber R of the first piston 5 and the middle cylinder chamber R between the first and second pistons 5 and 6 in succession, When the first piston 5 moves forward due to the action of the air, the air in the middle cylinder chamber R between the first and second pistons 5 and 6 is further compressed, causing the second piston 6 to move forward instantaneously. When the second piston 6 moves forward, compressed air is supplied to the front cylinder chamber R of the second piston 6 through the circumferential groove 31 and the communication passage L6.
The pressure in the front cylinder chamber R increases. At this time,
The second piston 6 instantaneously starts to retreat. In this case, the timing between the first piston 5 and the second piston 6 is to start retracting the second piston 6 just before the first piston 5 reaches the top dead center (the most advanced position), and then the second piston 6 When the first piston 5 starts retracting after the first piston 5 starts retracting, the first piston 5
The middle cylinder chamber R between the second pistons 5 and 6 always maintains a positive pressure, and on the one hand the second piston 6 is prevented from colliding with the front surface of the first piston 5 during its retreat, and on the other hand, the second piston 6 is prevented from colliding with the front surface of the first piston 5. To encourage smooth retreat of the piston 5. Further, when the first piston reaches the bottom dead center (the most retracted position) and then turns forward, the middle cylinder chamber R between the first and second pistons 5 and 6
Compressed air is then introduced again one after the other. At this time, the cylinder chamber is already at a positive pressure, and the pressure increasing effect of the compressed air introduced into the cylinder chamber at this time applies a large forward force to the second piston 6, so the second piston 6 The transition from point to forward motion is extremely smooth. In this way, the timing for retracting the first piston 5 is set immediately after the second piston 6 starts retracting, and as both the first and second pistons approach after the first piston 5 starts moving forward, Due to the increasing air pressure between the two pistons, the first piston 5 instantaneously moves the second piston 6 forward using compressed air as a medium, and waits until the first piston moves back the most to move the second piston 6 forward. The action of the compressed air supplied to the rear surface causes the piston to move forward, and just before the second piston reaches the most forward position, the action of the compressed air supplied to the front surface of the piston causes the second piston to move backward. Further, the first piston 5 is moved forward just before the second piston reaches its most backward position, and the back and forth movement of the second piston 6 is repeated based on the timing of the back and forth movement of both pistons. Thus, a tool such as a saw blade 8 directly connected to the second piston 6 can smoothly reciprocate.

In this way, when the reciprocating movement of the saw blade 8 is stopped when a load is applied to the cutting edge when the cutting operation is completed or during the cutting operation, or in order to determine whether the cutting is good or bad, , operation lever 23
By weakening the grip on the valve and moving the on-off valve 15 backward by the spring 17 of the valve mechanism V, the air introduction passage L' ₁ is closed, and when the supply of compressed air to the air introduction holes 11a and 11b is cut off, the first , the second pistons 5 and 6 stop, and at the same time, the reciprocating movement of the saw blade 8 also stops.

With this saw, you can of course cut straight lines,
By changing the saw blade to a thin saw blade, it is possible to cut fine curves, and the short blade length allows it to be used in narrow spaces. Therefore, it can be used, for example, to cut the body roof of an automobile, and in general, it can be used for all kinds of cutting such as cutting section steel and cutting resin. When the saw blade 8 becomes worn or damaged, it can be easily replaced with a new saw blade 8 by loosening the tightening screw 44 of the tightening band 43.

<Effect of the invention> As is clear from the description of the saw shown in the embodiment, the reciprocating tool according to the invention has the first piston, the second piston, the driving shaft, and the cutting blade aligned on the same axis in a straight line. The first and second pistons are arranged in parallel, and the first and second pistons are completely separated, so that on the one hand, compressed air is simultaneously supplied to both pistons individually, and on the other hand, the compressed air existing between the two pistons is supplied to the two pistons. The structure is such that a large amount of air pressure is instantaneously applied to both pistons in a well-timed manner when they try to move toward each other and when they try to move away from each other, resulting in an extremely high transmission rate of driving force and It works efficiently, and a large cutting power can be obtained with a small amount of consumption, and the cylinder and the first and second pistons can be made smaller, thereby making it possible to make the tool smaller. In particular, the interference effect of the shock waves acting between the two pistons, etc. ensures smooth driving with less compressed air, and can completely suppress the occurrence of vibrations. This in turn makes it possible to reduce the weight of the housing and the first and second pistons, allowing the use of aluminum for the housing and the use of lightweight alloys with special coating specifications for the first and second pistons, making it possible to reduce the weight of the tool. The overall weight can be significantly reduced.

Further, since the grinding tools such as saw blades and files are detachably attached to the chuck, the cutting tools and the grinding tools can be easily replaced.

Furthermore, since the chuck portion is supported in a reciprocating manner by slide grooves provided symmetrically in a guide holder fixed inside the housing, stress in the vertical direction is not applied to the grinding tool. Even if stress is applied in the left and right direction,
This has the effect of stabilizing the movement of the abrasive cutting tool and maintaining unchanging sharpness within the service life of the abrasive cutting tool.

As described above, the present invention satisfies all the conditions required for hand-held tools, including vibration prevention measures, chip scatter prevention measures, noise prevention measures, and measures to facilitate the replacement of cutting tools and grinding tools. from,
It has great practical value.

[Brief explanation of the drawing]

The drawings show an example of a saw in which the present invention is implemented. Fig. 1 is an overall perspective view, Fig. 2 is a longitudinal side view, Fig. 3 is an exploded perspective view of the component parts, and Fig. 4 is a perspective view of the saw. Figure A is a vertical side view of the housing, the fourth
FIG. 5A is a longitudinal sectional side view of the cylinder, FIG. 5B is a longitudinal sectional end view, and FIG. 6 is a front view of the rear end member. DESCRIPTION OF SYMBOLS 1... Housing, 2... Cylinder, 3... Tip member, 4... Rear end member, 5... First piston,
6...Second piston, 7...Shaft, 8...Saw blade, 26...Double hose, _L1 , L' ₁ ...Air introduction passage, _L2 , L' ₂ ...Air discharge passage, V... Valve mechanism.

Claims (1)

[Scope of utility model registration request] A cylinder is inserted into a housing that also serves as a grip to form an air introduction passage and an air discharge passage between the housing and the cylinder, and first and second free pistons are axially disposed inside the cylinder. The front and rear ends of the housing are fitted adjacently so as to be movable back and forth, and one end of the housing is connected to a tip member and an operating lever that movably support a support mechanism of a cutting and grinding tool such as a saw blade, which is fixed to a second free piston. Thus, the compressed air supply passage is closed by a rear end member provided with a valve for opening and closing the compressed air supply passage, respectively, to form front, middle and rear cylinder chambers in the cylinder, and the cylinder has the air introduction passage and the air introduction passage. Two air introduction holes and four air exhaust holes are provided, each communicating with the exhaust passage, and the air exhaust holes are located at positions where they are respectively closed at the front and rear outer peripheral ends of the first and second free pistons when in neutral. The air inlet hole is located approximately at the center of the first and second free pistons when in neutral state, and is connected to the first and second free pistons when in operation. The first and second free pistons have communication passages that communicate with each of the circumferential grooves and the cylinder chamber alternately. A pneumatic reciprocating tool, wherein the first and second free pistons are arranged to operate in opposite directions when compressed air is supplied.