JP3711095B2 - Belt grinding tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a belt-type grinding tool having an endless grinding belt tensioned by a pair of driven pulleys and drive pulleys, and in particular, a single valve is operated to rotate the grinding belt, to drive and stop the grinding belt. The present invention relates to a belt-type grinding tool that can be switched easily and can perform grinding without inconvenience for both right-handed and left-handed workers.
[0002]
[Prior art]
The structure of a conventionally known belt-type grinding tool will be described with reference to FIG. 9. In the figure, 101 is a grip, 102 is a prime mover (air motor) integrated with the grip, 103 is a drive roller (drive pulley), and 104 is a spring. The built-in arm, 105 is a tension rod (tension bar) pressed by the spring, 106 is a support arm of a driven roller (driven pulley) 107 attached to the rod, and 108 is between the driving roller and the driven roller. A stretched grinding belt, 109 is a shoe, and 110 is a belt cover. In the belt-type grinding tool having the above-described configuration, the grip is held with the right hand, the motor 102 is driven to rotate the grinding belt 108, and the belt is applied to the surface of the workpiece to be ground (not shown). Grind the surface.
[0003]
[Problems to be solved by the invention]
However, the belt-type grinding tool as described above is usually set in a positional relationship between the grip and the grinding belt in accordance with a right-handed worker. Therefore, if a left-handed worker uses this grinding tool, use it. The aspect becomes unnatural. That is, since the left-handed worker holds the grip with the left hand of the dominant hand and performs the grinding work, the belt position is further left than the left hand during the work, and the grinding work is extremely difficult. Also, if the grip of the belt-type grinding tool is reversed 180 degrees (in the state shown in the figure, the grip is at the front and the grinding belt is on the top of the figure), and you try to hold the grip with your left hand, Due to the mounting angle and positional relationship between the belt and grip, the posture when the grinding belt is applied to the grinding part becomes unnatural, making it difficult to work. Further, in the conventional belt-type grinding tool, since the rotation direction of the grinding belt is constant, it is not possible to select the rotation direction preferred by the operator, and the usability is poor. In addition, when the grinding belt is replaced when the grinding belt is cut or worn, with this belt-type grinding tool, it is necessary to push the tension rod by hand against the urging force of the spring. There are problems such as misalignment.
[0004]
Therefore, according to the present invention, the rotation direction of the grinding belt can be freely selected by operating only one valve, and the rotation of the air motor can be stopped at any position, and the tension bar is fixed when the grinding belt is replaced. An object of the present invention is to provide a belt-type grinding tool that employs a lock mechanism capable of solving the problems of the conventional belt-type grinding tool. It is another object of the present invention to provide a belt-type grinding tool that can easily change the position of an offset bracket having a tension pulley up and down according to the state of use of the belt.
[0005]
In the present invention, by rotating one valve forward and rotating it, the air flow can be switched to rotate the grinding belt in the normal direction and reverse direction. The structure is such that the flow is interrupted and the rotation of the grinding belt can be stopped. For this reason, in this belt type grinding tool, even if the direction of the grinding tool itself is left-handed and upside down in accordance with right-handedness, the rotation direction of the grinding belt can be freely selected, and it is extremely convenient. Therefore, in particular, a left-handed worker can work with the same feeling of use as a right-handed worker. When it is necessary to replace the grinding belt, the tension bar position can be fixed simply by pushing the tension bar and locking the state, so that the grinding belt can be easily replaced.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the technical solution adopted by the present invention is:
An endless grinding belt is stretched between a driven pulley attached to the tip of a tension bar attached to the housing so as to freely advance and retract, and a driving pulley attached to an air motor attached in the housing, and the grinding belt can be driven to rotate by the air motor. A belt-type grinding tool configured as described above, wherein a valve capable of supplying and exhausting air to the air motor is provided in a housing of the belt-type grinding tool, and the air motor can be rotated or stopped by moving the valve forward or backward. The belt-type grinding tool is characterized in that the rotation of the air motor can be rotated forward or reverse by rotating it to the right or left in a state where the head is advanced.
The valve includes a valve main body having an air supply passage and an air exhaust passage, and a valve ring that is non-rotatable and slidably attached to the valve main body. Is an annular groove that communicates an air supply passage formed on the valve body side with an air source, a seal ring that shuts off the air source on both sides of the annular groove, and a guide groove formed in the axial direction of the valve body. And a valve ring is advanced along the guide groove of the valve body so that the air supply passage communicates with the air source through the annular groove. By rotating the valve ring to the right or left, the valve main body also rotates in conjunction with the protrusion, and the air supply passage formed in the valve main body communicates with the air supply / exhaust hole of the air motor mounted in the housing, Airmor A belt type grinding tool, characterized in that to be able to forward or reverse.
In addition, a stopper made of an elastic body is provided at one end of the valve ring, and an inclined surface projecting inward is formed on the inner peripheral surface of the opposite end of the housing, and the stopper passes through the inclined surface. The valve ring can be moved forward only when the stopper is in a position facing the passage, and the valve ring can be moved over the inclined surface at any position. It is a belt type grinding tool characterized in that it can be moved backward.
The belt-type grinding tool is characterized in that a ring member in which the passage portion and the inclined surface are formed is attached to the inner peripheral surface of the end portion of the housing.
The tension bar is provided with a lock mechanism capable of locking the tension bar while the tension bar is pushed in.
The belt-type grinding tool is characterized in that an offset bracket having a tension pulley can be detachably attached to the housing at a position closer to the drive pulley of the housing.
[0007]
Embodiment
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a belt-type grinding tool according to this embodiment, FIG. 2 is a side view thereof, and FIG. FIGS. 4A to 4C are explanatory views of the structure and operation of the tension bar locking mechanism, FIG. 5 is an enlarged cross-sectional view of the air motor portion, and FIGS. 6A and 6B are valve rings constituting the valve. FIG. 7 is a view of the valve body, (A) is a plan view, (B) and (C) are sectional views, (D) is a side view, and FIGS. (C) is an explanatory view of the operation of the valve, and is a development view showing the cross section of the cylinder and the state of air supply and exhaust by the valve main body.
[0008]
A belt-type grinding tool (hereinafter referred to as a grinding tool) according to the present invention includes a tension mechanism T that holds a grinding belt, a grinding belt B that is stretched between a driving pulley and a driven pulley, and an air motor A that imparts rotational force to the grinding belt. It is composed of a built-in grip G, a valve V that supplies air to the air motor A and exhausts air from the air motor A, and the rotation of the air motor A can be rotated forward or backward by operating the valve V attached to the grip G. The surface of the object to be ground can be ground by reversing and selecting the rotation of the grinding belt in the forward direction or the forward direction of the operator. Hereinafter, the configuration will be described in detail for each component.
[0009]
[Tension mechanism]
2 and 3, reference numeral 1 denotes a tension bar, and a pulley holding member 3 for holding the driven pulley 2 rotatably is attached to the tip of the tension bar. The pulley holding member 3 is attached to the tip of the tension bar 1 so as to be swingable in the vertical (arrow) direction in FIG. 3 by a shaft 4, and further includes a screw 5 for adjusting the swing angle, an adjustment screw 6 and A spring 7 is provided between the two. With this configuration, the pulley holding member 3 is adjusted in angle with the shaft 4 as a fulcrum by screwing or loosening the adjusting screw 6 against the urging force of the spring 7 in FIG. It can be positioned on the center of the tension bar 1. At this time, the pulley holding member 3 is fixed with the screw 5 at the adjusted angle.
[0010]
The end of the tension bar 1 opposite to the driven pulley 2 is slidably inserted into a long hole 8 a provided in the housing 8, and a cylindrical member 9 is attached to the end of the long hole 8 a with respect to the housing 8. It is fixed with screws 10. Further, a notch 11 (upper and lower in FIG. 3) is formed in the cylindrical member 9 in parallel with the axis of the tension bar 1, and a pin 12 attached to the tension bar 1 is inserted into the notch 11. The pin 12 is configured to prevent the tension bar 1 from rotating about the axis.
[0011]
3 and 4, a small diameter portion 13a is formed at one end (right side in the drawing) of the tension bar 1 inserted into the long hole 8a of the housing 8, and a step between the small diameter portion 13a and the large diameter portion 13b. A circumferential groove 14 is formed at the portion, and a plurality of protrusions 15 are formed at the end of the tension bar 1. A spring receiving member 16 is disposed at the right end of the tension bar 1 in the figure, and a tension spring 17 is disposed between the spring receiving member 16 and the housing 8. In addition, an L-shaped push button 18 is disposed in the housing 8 as shown in FIG. 4A, and the tension bar 1 is disposed through the push button 18. The push button 18 is urged downward in the figure by a spring 19, and when the grinding belt B is stretched, the push button 18 comes into contact with the small diameter portion 13a of the tension bar 1 as shown in FIG. ing.
[0012]
With the above configuration, when exchanging the grinding belt B, when the tension bar 1 is pushed against the urging force of the tension spring 17, it is formed at the step portion between the small diameter portion 13a and the large diameter portion 13b. When the circumferential groove 14 comes to the position of the push button 18, the push button 18 falls into the circumferential groove 14 by the biasing force of the spring 19 (see FIG. 4 (a)), and the movement of the tension bar 1 is locked. In this state, the grinding belt B is replaced. Further, when the grinding belt B is cut during the operation, the tension bar 1 tries to jump out from the state shown in FIG. Since the plurality of protrusions 15 provided at the end are hooked on the push button 18 (see FIG. 4C), the tension bar 1 is prevented from popping out. In order to return the replaced grinding belt B to the tensioned state (the state shown in FIG. 4B), when the push button 18 is pushed against the urging force of the spring 19, the push button 18 is moved to the circumferential groove. 14, the tension bar slides to the left in the figure and returns to the state shown in FIG.
[0013]
In FIG. 2, a housing 8 is formed with a space between the grinding belt B and the tension par 1, and a tension pulley 20 for grinding a curved surface of a workpiece (not shown) is rotatably supported. A bracket 21 is attached. The offset bracket 21 has a U-shape on the tension pulley 20 side, and the plates 21 a and 21 b on both sides of the U-shape are extended so that they can be inserted into the guide grooves 22 of the housing 8 and attached to the housing 8. (In FIG. 2, the offset bracket 21 is fitted in the housing 8 from the lower side to the upper side in the figure). 2, the offset bracket 21 can be pulled out downward and removed from the housing 8, and the offset bracket 21 can be inserted again from above the housing 8 with the tension pulley 20 on the upper side (in this case, left-handed) The operator uses the grinding tool by turning it 180 degrees). Furthermore, both side plates 21a and 21b of the offset bracket 21 are provided with projections 23 and 23 projecting inward, and a fitting recess (not shown) is formed on the housing 8 side so that the offset bracket 21 is inserted, By fitting the protrusions 23 into the recesses on the housing 8 side, the positioning of the offset bracket 21 to the housing 8 and the falling off of the offset bracket 21 from the housing 8 can be prevented. It can be freely set at the time of designing whether the protrusion 23 and the fitting recess for preventing such a drop are provided on the offset bracket 21 or the housing 8.
[0014]
[Air motor]
The air motor has a configuration similar to that of a conventional grinding tool. When air is supplied, a rotor having blades in the motor rotates, whereby the grinding belt can be rotated via a drive pulley.
In FIG. 5, the air motor A includes a cylinder 24 mounted in the housing 8 with an eccentric inner diameter, a rotor 25 having a blade 25 a rotatably disposed in the cylinder 24, and a plate that sandwiches the rotor 25 from both sides of the cylinder 24. The shafts 26 at both ends of the rotor 25 are pivotally supported by bearings 27 provided on the plates 24c and 24d. A driving pulley 28 is fixed to an end portion of one side (lower side in the drawing) shaft 27 of the rotor 25 by a nut 29. The driving pulley 28 and the driven pulley 2 provided at the tip of the tension bar 1 described above. An endless grinding belt B is attached to the tension pulley 20 (see FIG. 1).
[0015]
The cylinder 24 is formed with holes 24a and 24b for supplying and exhausting air (details will be described later in a valve mechanism), and the air is exhausted between the outer periphery of the cylinder 24 and the housing 8. A flow path 30 is formed. The opposite wall 8 of the housing 8 has two holes 8a and 8a (see FIG. 8 to be described later) for supplying or exhausting air to the air motor A, and an exhaust hole 31 communicating with the flow path 30. 31 is formed, and a valve body 33 of a valve V described later is arranged facing the two holes 8a and 8a. In this air motor A, when the valve V is operated, air is supplied into the air motor A and the rotor 25 is rotated. The air supplied into the cylinder 24 is configured to be exhausted to the outside through the exhaust hole 31 and the exhaust hole 8a through the flow path 30 after rotating the rotor 25 having the blade 25a. Further, a cover 32 that can be removed for exchanging the grinding belt B or the like is detachably attached to the outside (lower side in FIG. 5) of the drive pulley 28 by screws 32A (see FIG. 3).
[0016]
[Valve mechanism]
6, 7, and 8, the valve V is for supplying and exhausting air to the air motor A described above, and includes a valve main body 33 and a valve ring 34. The valve ring 34 is a valve main body. It is attached to the outer periphery of 33 so as not to be relatively rotatable and slidable. With this configuration, when the valve ring 34 is advanced on the valve body 33, air can be supplied to the air motor A via the valve body 33, and when the valve ring 34 is further rotated, the valve body 33 is also rotated. Rotating in conjunction with each other, air can be supplied from the valve body 33 to the air motor A (detailed configuration will be described later).
[0017]
The valve body 33 has the shape shown in FIG. 7, and as shown in FIG. 6, one end of the valve body 33 is fixed to the housing 8 by a fixing ring 35 and a ring nut 36 so as to be rotatable about its axis. ing. A first supply passage 37 and a second supply passage 38 are formed in the central portion of the valve body 33, and communication holes 39 and 40 communicating with the outer periphery of the valve body 33 are formed in the supply passages 37 and 38. ing. Further, the second air supply passage 38 is provided with a seal ring 41 around the outlet thereof, and through the seal ring 41, the housing 8 having two holes 8a for air supply / exhaust (see the right side development view of FIG. 8). It is in contact with the surface (see FIG. 6). In FIG. 6, the upper half of the housing 8 is illustrated with the air supply / exhaust hole 8 a, and the lower half is illustrated with the exhaust hole 31.
[0018]
The valve body 33 is provided with a pin 42 for restricting the rotation angle of the valve body 33, and the pin 42 is fitted into a recess 8b formed on the housing side. For this reason, the valve body 33 can move in the recess 8b from the neutral position in FIG. 8 until the pin 42 hits the left and right walls of the recess 8b. The first air supply passage 37 is provided with an air supply hose connection portion 52 as shown in FIG. Further, an exhaust passage 43 is formed in the valve body 33 as shown in FIGS. 6 and 7, and the exhaust passage 43 is formed on the outer periphery of the air supply hose connection portion 52 (see FIG. 6). The air can be discharged to the outside air through the exhaust hose 54.
[0019]
A valve ring 34 is disposed on the outer periphery of the valve body 33 so as not to rotate but to slide freely. That is, a guide groove 45 is formed on the outer periphery of the valve body 33 in the axial direction, and a protrusion 46 formed on the inner periphery of the valve ring 34 is fitted into the guide groove 45 so that the two are relatively non-rotatable. It is comprised so that it may become. An annular groove 47 that communicates the communication holes 39 and 40 of the valve body 33 is formed on the inner periphery of the valve ring 34. Seal rings 48 are provided on both sides of the groove 47 to seal the outer peripheral surface of the valve body 33 and the inner peripheral surface of the housing 8. This one seal ring 48 is disposed between the communication hole 39 and the communication hole 40 when the valve ring 43 is retracted, and stops air supply to the air motor A.
[0020]
Further, a stopper 49 made of a spring material is fixed to the valve ring 34 so as to repel in the inner and outer diameter directions, and a passage portion through which the stopper 49 can pass on the opposite housing 8 side. The valve stopper ring 50 which has the step part 50b and the inclined surface 51 which block 50a and approach is provided. In this example, the passage portion 50a is formed by cutting out a part of the valve stopper ring 50. As shown in FIG. 6, the valve stopper ring 50 has a shape having an inclined surface 51 projecting inward. Therefore, the valve ring 34 can be advanced from the state shown in FIG. 6 (a) to the state shown in FIG. 6 (b) only when the stopper 49 passes through the passage portion 50a provided in the valve stopper ring 50. The ring 34 is configured so that the stopper 49 can be deformed and retracted from any position of the rotation angle with respect to the housing 8. When trying to advance the valve ring from another position, the stopper 49 comes into contact with the stepped portion 50b to prevent the valve ring 34 from moving forward. In this example, the step portion 50b is formed, but it may be a simple end portion.
[0021]
When the valve ring 34 is advanced in a state where the stopper 49 can pass through the passage portion 50a provided in the stopper ring 50, one seal ring 48 provided on the inner periphery of the valve ring 34 is positioned in front of the passage hole 40, The annular groove 47 is positioned so as to straddle the communication hole 39 and the communication hole 40 on the valve body 33 side, and communicates with the first air supply passage 37 and the second air supply passage 38 (FIG. 6 (B)). reference). When the valve ring 34 is rotated in this state, the valve body 33 rotates until the pin 42 hits the wall of the recess 8 b formed in the housing 8, and the second air supply passage 38 formed in the valve body 33 is formed in the housing 8. The air motor A can be rotated by communicating with one of the air supply / exhaust holes 8a and the other air supply / exhaust hole 8a with the exhaust passage 43 formed in the valve body 33 (see FIG. 8). ). During the rotation of the air motor A, the exhaust air from the air motor A is exhausted from the flow path 30 (see FIG. 5) formed between the cylinder 24 and the housing 8, the exhaust hole 31 formed in the housing 8, and the valve body 33. It is discharged to the outside air through the passage 43 and the exhaust hose 54. When the valve ring 34 is retracted while the air motor A is rotating, the stopper 49 is elastically deformed and moves over the inclined surface 51 of the valve stopper ring 50. As a result, one seal ring 48 provided on the inner periphery of the valve ring 34 is positioned between the communication hole 39 and the communication hole 40, and the communication state of the first supply passage 37 and the second supply passage 38 is blocked. The rotation of the air motor can be stopped.
[0022]
As shown in FIG. 8, the cylinder 24 having an eccentric inner diameter disposed opposite to the valve V having the above-described configuration includes a rotor 25 having a blade 25 a therein, and further includes two holes for supplying and exhausting air. 24a and an exhaust hole 24b are formed. The housing 8 disposed on the outer periphery of the cylinder 24 is formed with the above-described hole 8a corresponding to the air supply / exhaust hole 24a of the cylinder 24, and the housing 8 has the above-described configuration via the seal ring 41. A valve body 33 is disposed (see FIGS. 5 and 6). Therefore, when the valve ring 34 is moved forward and the valve body 33 is rotated through the valve ring 34 in this state, the second air supply passage 38 and the one side hole 8a formed in the housing 8 and the one formed in the cylinder 24 are provided. Air is supplied into the cylinder 24 through the side hole 24a, and the rotor 25 can be rotated through the blade 25a (see FIG. 8). At this time, one of the air exhausted from the air motor A enters the passage 30 formed between the cylinder 24 and the housing 8 from the exhaust hole 24b of the cylinder 24, passes through the exhaust hole 31, and the valve body 33. The other reaches the exhaust passage 43 from the other exhaust hole 24a through the other air supply / exhaust hole 8a to the exhaust passage 43, and both air are discharged to the outside air through the exhaust hose 54.
[0023]
The operation of the grinding tool having the above configuration will be described.
In FIG. 3, when the valve ring 34 is rotated so that the stopper 49 provided on the valve ring 34 is advanced in accordance with the passage 50 a of the valve stopper ring 50 provided on the housing 8, the seal ring provided on the inner periphery of the hub ring 34. One of the 48 is located in front of the communication hole 40 and the groove 47 extends between the communication hole 39 and the communication hole 40 and connects the first supply passage 37 and the second supply passage 38. At this time, the air is not supplied to the air motor A in a neutral state (FIG. 8B). When the valve ring 34 is rotated in this state, the valve main body 33 is also rotated in conjunction with movement until the pin 42 provided at the tip of the valve main body 33 comes into contact with the wall of the recess 8b formed in the housing 8 (FIG. )), The second air supply passage 38 communicates with one of the air supply / exhaust holes 8a formed in the housing 8, rotates the air motor A, and the rotation of the air motor A rotates the grinding belt B. Grinding work can be performed. Further, when the valve ring 34 is rotated in the reverse direction with the valve ring 34 being advanced, the valve main body 33 is also rotated in the reverse direction, so that the pin 42 provided on the valve main body 33 is connected to the housing 8. It rotates until it hits the wall of the recess 8b on the opposite side formed on the side (the state shown in FIG. 8C), and the second air supply passage 38 is on the side opposite to the air supply / exhaust hole 8a formed in the housing 8 Communicating with the hole 8a, the air motor A can be rotated in the opposite direction, and the air motor A can be reversed to rotate the grinding belt B in the reverse direction.
[0024]
In order to finish the grinding operation, when the valve ring 34 is retracted as it is, the stopper 49 is deformed to get over the inclined surface 51 of the valve stopper ring 50 and the groove 47 formed on the inner periphery of the valve ring 34 is sandwiched. One of the reel rings 48 provided in FIG. 4 is located between the communication hole 39 and the communication hole 40 and can shut off the air to stop the rotation of the air motor A.
[0025]
When exchanging the grinding belt B, the rotation of the air motor A is stopped, the attachment screw 32A is operated to remove the cover 32, and the tension bar 1 is pushed against the urging force of the tension spring 17. When the circumferential groove 14 formed in the tension bar 1 comes to the position of the push button 18, the push button 18 falls into the circumferential groove 14 by the biasing force of the spring 19, in other words, the push button 18 is pushed by the biasing force of the spring 19. The button 18 is pushed outward (see FIG. 4A), the movement of the tension bar 1 is locked, and the grinding belt B can be replaced in this state.
[0026]
When the grinding belt B is cut during the operation, the tension bar 1 pops out to the left in the figure by the urging force of the tension spring 17, but the protrusion 15 provided at the end of the tension bar 1 has the push button 18. Therefore, the tension bar 1 can be prevented from jumping out of the housing 8.
Further, when the left-handed operator uses the pneumatic grinding tool in a normal state (the grinding belt B rotates counterclockwise), the offset bracket 21 attached to the lower side of the housing 8 is changed to the upper side, and the grinding tool is used. Is rotated 180 degrees to advance the valve ring 34 and rotate the valve ring 34 in the reverse direction. The rotating direction of the grinding belt B can be switched by rotating the valve main body 33 forward and backward via the valve ring 34 in accordance with the working conditions. Further, when the work is finished or stopped, the rotation of the air motor A can be stopped only by retracting the valve ring 34 as described above. When the offset bracket 21 is attached, curved grinding can be performed, and surface grinding can be performed by removing the offset bracket.
[0027]
Although the embodiment according to the present invention has been described above, the air passage formed in the valve ring, the valve main body, and the housing can have various passage shapes as long as the above-described functions can be achieved. Various means such as a screw can be adopted as means for fixing the offset bracket. Further, the above-described embodiments are merely examples, and the present invention can be implemented in various other forms without departing from the spirit or main features of the present invention, and should not be interpreted in a limited manner.
[0028]
【The invention's effect】
As described in detail above, according to the present invention, the grinding belt can be rotated and stopped only by operating one valve, and the rotation direction of the grinding belt can be freely selected. Even right-handed and left-handed workers can grind with the same feeling. Further, since the grinding powder scattering direction can be selected by switching the rotation direction of the grinding belt, the work efficiency is improved. In addition, when the belt is replaced, a lock mechanism that can easily fix the tension bar is employed, so that the replacement work of the grinding belt is facilitated. Furthermore, since the offset bracket having the tension pulley can be detachably attached, it is possible to achieve excellent effects such as easy grinding even on a curved surface.
[Brief description of the drawings]
FIG. 1 is a plan view of a belt-type grinding tool according to an embodiment.
FIG. 2 is a side view of the same.
FIG. 3 is a plan sectional view of the same.
FIGS. 4A to 4C are explanatory views of the configuration and operation of the lock mechanism. FIGS.
FIG. 5 is an enlarged cross-sectional view of an air motor portion.
6A and 6B are cross-sectional views for explaining the operation of the valve ring and the valve body.
7A is a plan view, FIG. 7B is a sectional view, and FIG. 7D is a side view.
FIGS. 8A to 8C are operation explanatory views of a valve, and are development views showing a cross section of a cylinder and states of air supply and exhaust by a valve main body.
FIG. 9 is a conventional belt-type grinding tool.
[Explanation of symbols]
1 Tension bar
2 driven pulley
3 Pulley holding member
4 axis
5 Screw
6 Adjustment screw
7 Spring
8 Housing
8a long hole
9 Tube member
10 screws
11 Notch
12 pins
13 Small diameter part
14 Circumferential groove
15 protrusions
16 Spring receiving member
17 Tension spring
18 Push button
19 Spring
20 Tension pulley
21 Offset bracket
22 Guide groove
23 Protrusions
24 cylinders
25 impeller
26 axes
27 Bearing
28 Drive pulley
29 nuts
30 channels
31 holes
32 Cover
33 Valve body
34 Valve ring
35 Fixing ring
36 Ring nut
37 1st air supply passage
38 Second air supply passage
39, 40 holes
41 Seal ring
42 pins
43 Exhaust passage
45 Guide groove
46 protrusion
47 Groove
48 seal ring
49 Stopper
50 Stopper ring
50a passage
50b Step
51 Inclined surface
53 Exhaust passage

Claims (6)

An endless grinding belt is stretched between a driven pulley attached to the tip of a tension bar attached to the housing so as to be able to advance and retract, and a drive pulley attached to an air motor attached in the housing, and the grinding belt can be rotationally driven by the air motor. A belt-type grinding tool configured as described above, wherein a valve capable of supplying and exhausting air to the air motor is provided in a housing of the belt-type grinding tool, and the air motor can be rotated or stopped by moving the valve forward or backward. A belt-type grinding tool, wherein the rotation of the air motor can be rotated forward or backward by rotating it to the right or left in a state of moving forward. The valve includes a valve body having an air supply passage and an air exhaust passage, and a valve ring that is non-rotatable and slidably attached to the valve body. An annular groove that communicates an air supply passage formed on the valve body side with an air source, a seal ring that shuts off the air source on both sides of the annular groove, and a guide groove formed in the axial direction of the valve body. A projection that fits freely, and the valve ring is advanced along the guide groove of the valve body so that the air supply passage communicates with the air source through the annular groove. In this state, the valve ring The valve body is also rotated in conjunction with the projection by rotating the valve to the right or left, and the air supply passage formed in the valve body is communicated with the air motor supply / exhaust hole mounted in the housing. Positive Or belt type grinding tool according to claim 1, characterized in that to be able to reverse. A stopper made of an elastic body is provided at one end of the valve ring, and an inclined surface projecting inward is formed on the inner peripheral surface of the end of the opposing housing, and the stopper can pass through the inclined surface. The valve ring can advance the valve ring only when the stopper is in a position facing the passage portion, and the valve ring can be moved back over the inclined surface by the stopper at any position. The belt-type grinding tool according to claim 2, wherein the belt-type grinding tool can be made to be able to be made. The belt-type grinding tool according to claim 3, wherein a ring member in which the passage portion and the inclined surface are formed is attached to an inner peripheral surface of the end portion of the housing. The belt-type grinding tool according to any one of claims 1 to 4, wherein the tension bar is provided with a lock mechanism that can lock the tension bar while the tension bar is pushed in. The belt-type grinding according to any one of claims 1 to 5, wherein an offset bracket having a tension pulley can be detachably attached to the housing near the drive pulley. tool.

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