JPS632662A - Polishing method for profile rotary sander - Google Patents

Abstract

PURPOSE:To carry out efficient and favorable machining by controlling the pressing force of a presser pad in accordance with the curvature, in a part where the peripheral edge of a workpiece is bent and making a pressing force to a polishing surface always proper. CONSTITUTION:In a part where the peripheral edge of a workpiece is bent, the pressing force of a presser pad 42 is controlled in accordance with the curvature and the pressing force per unit contact area is adjusted, to prevent excessive cutting. In order to control this pressing force, a pressure regulator is installed in between a compressor and an actuator 47, and connected to a control device to regulate air pressure in accordance with the curvature of a part to be polished. Or else, two or more regulators having different regulating pressures are connected in parallel to the actuator 47, and closing valves are provided on the regulators respectively, each being connected to the control device to carry out regulation by opening one of the valves. Thereby, the pressing force of a sanding belt 41 to a polishing face is always made proper to carry out efficient and favorable machining.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a polishing method in a profile rotary sander that automatically polishes the peripheral edge of a flat workpiece.
In particular, it is characterized in that the pressing force of the presser butt is increased or decreased in accordance with the magnitude of the curvature of the peripheral edge.

(Prior Art) Generally, a profile rotary sander is used when polishing the periphery of a plate-like material such as a material for wooden furniture or a material for a wooden musical instrument. This is a type of bell or tosander, in which a sanding belt is suspended from a pulley arranged in a triangular shape, and a presser pad is attached to the inside of the sanding belt, and this presser pad is used to apply sand to the area to be polished on the periphery of the workpiece. This is done by pressing a sanding belt against it.

Of course, this device is an automatic machine, and consists of a sanding machine with a sanding unit as its main body, and a workpiece holding device.The workpiece is attached to the holding device and rotated, or The workpiece is fixed and the sanding machine is rotated while the sanding unit is moved along the periphery of the workpiece to polish it.

By the way, a belt sander has a presser pad formed to an appropriate length, and its pressing surface has a shape that corresponds to the shape of the surface to be polished of the workpiece, and the sanding belt is placed flush against the surface to be polished. It is distinctive in that it is designed to make contact, but if there is a curved part on the periphery of the workpiece, the shape of the pressing surface of the presser pad will not correspond to the shape of the surface to be polished at that part. , the contact area of the sanding belt with the surface to be polished is reduced. In other words, the pressing force per unit area of the sanding belt against the polishing surface increases in this portion.
As a result, a large amount of polishing was required in this area, causing problems due to over-shaving. In an attempt to eliminate this problem, attempts have been made in the past to shorten the polishing time by increasing the moving speed of the sanding unit relative to the curved edge of the workpiece. However, with this method, control of the amount of polishing is extremely slow, the amount of polishing is not constant, and it is inevitable that the finish will be rough and uneven.

(Means for Solving the Problems) The present invention has been made in view of the above-mentioned points, and the pressing force of the presser pad is adjusted in accordance with the curvature of the curved portion of the periphery of the workpiece. The amount of polishing is kept constant by appropriately adjusting the pressing force per unit area of the sanding belt against the surface to be polished.

(Examples) Hereinafter, the present invention will be specifically described based on illustrated examples.

Reference numeral 1 in the figure is a holding device provided in the center of the device, which holds the workpiece A, and one or more sanding machines 2 are attached to the holding device 1 on the side. They are placed facing each other. In Figure 1, workpiece material A
This shows an example of a method in which the outer periphery of the blade is polished while rotating the blade. Therefore, the holding device is equipped with a mechanism for rotating the workpiece A, while the sanding machine 2 is equipped with an advancing/retracting mechanism, a swinging mechanism for the sanding unit, and the like.

These devices will be explained in more detail.

First, the holding device will be explained. Reference numeral 10 is a base, and a boss 11 is erected at the center of the base, and a work table 12 is rotatably supported on this.
A rotating shaft 13 is provided on the bottom surface of this work table 12.
Further, a drive motor 14 is connected to this rotating shaft 13 via a rotation transmission mechanism such as a worm gear, and the rotation of the drive motor 14 is transmitted to the work table 1.
2.

Further, a work holding plate 15 is provided above the work table 12. This is for pressing and fixing the workpiece A on the work table 12, and is rotatably and movably attached to the tip of the support frame 16 extending from the corner of the base 10. It is.

By the way, the workpiece A will be subjected to quite strong lateral pressure during processing, so it is important to withstand this lateral pressure and attach it so as not to shift on the work table 12.

Next, the sanding machine 2 will be explained. Although FIG. 1 shows an example in which two sanding machines 2 are provided on both sides of the work table 1, the present invention is not limited to this. There isn't. The sanding machine 2 consists of a base, a support stand, and a sanding unit 21, and the polishing surface of the sanding unit 21 is inclined according to the shape of the surface to be polished of the workpiece A, so that the surface to be polished can be polished as desired. It is designed so that it can be machined into any shape, and is configured to move forward and backward as the workpiece A rotates, so as to always face the surface to be polished. Reference numeral 22 is a fixed pedestal, 23 is a movable pedestal, and 24 is a rotating pedestal. These are the bases that support the sanding unit 21, and allow the sanding unit 21 to move forward and backward and oscillate. The board 23 is supported by the fixed frame 22 so as to be able to move forward and backward.

That is, two rails 25 are provided on the upper surface of the fixed frame 22 facing the holding device 1, and the movable platform 23 is slidably attached to the rails 25. A male screw rod 26 is attached to the fixed frame 22 in parallel with the rail 25, while a female spiral 27 is attached to the movable platform 23, which is screwed into the male screw rod 26, and the motor 2
8, the movable base plate 23 is moved forward and backward by rotating the male screw rod 26 forward and backward. The movable base plate 23 has an arcuate rear edge and a rail 29 is attached thereto, and a pivot shaft 30 is erected at the center thereof, on which the pivot base 24 can freely pivot. installed on. A driving wheel 31 that meshes with the rail 29 is attached to the rear end of the rotating frame 24. Furthermore, this driving wheel 31 is connected to a motor 32 via a bevel gear or the like, and the driving wheel 31 is rotated in the forward and reverse directions. By doing so, the pivot frame 24 is pivoted about the pivot shaft 30.

Next, the support stand will be explained. It consists of a support post 33 and a mounting frame 34.
A sanding unit 21 is attached to 4.
Since these are the same as those of a normal profile rotary sump of this type, a detailed explanation of the structure will be omitted. The frame 34 is supported by the support post 33 so that it can move forward and backward, and can go up and down. The sanding unit 21 is attached to a mounting frame 34 so as to be able to freely adjust the elevation angle, and the sanding unit 21 can be adjusted in accordance with the thickness of the workpiece A, the surface angle of the surface to be polished, the shape of the presser pad (described later), etc. By adjusting the position and elevation angle, the polishing surface of the sanding unit 21 is brought into alignment with the surface to be polished.

Next, the sanding unit 21 attached to this attachment frame 34 will be explained. First.

A drive motor 36 is attached to the rear of the substrate 35, a pulley 37 is attached to its output shaft, and a pair of left and right guide pulleys 38, 39 are attached to the front of the substrate 35. One of the guide pulleys 38 is fixedly attached to the base plate 35, and the other guide pulley 39 is attached to the base plate 35 via a rotating arm 40, and is always biased outward by compressed air or the like. It is configured. A sanding belt 41 is stretched on a track forming a substantially isosceles triangle formed by the pulley 37 and guide pulleys 38 and 39 of the belt drive motor. This sanding belt 41 is made by fixing abrasive grains to the surface of a base belt material, and polishes the surface of the workpiece A on this polishing surface.

A presser pad 42 is applied to the back of the sanding belt 41 between the guide pulleys 38 and 39, thereby obtaining a desired processed cross-sectional shape.

That is, the front surface of the presser pad 42 has a shape that is almost similar to the desired cross-sectional shape of the workpiece A, and the sanding belt is guided and deformed along that shape to obtain the desired processed shape. Incidentally, since this point is similar to that of the already known sump, further detailed explanation will be omitted. Next, the shift end of this presser pad will be explained. Reference numeral 43 denotes a pair of left and right guide rails attached to the board 35, and the guide rails 43 are horizontally attached to the support bracket 44 raised from the board 35 toward the tip. There is. A slider 45 is attached to this guide rail, and the presser pad 42 is attached to the front center of the slider 45. Note that the presser pad 42 is replaced with a bolt so that it can be replaced as needed to change the processed shape.

A cylinder 46 is attached to the slider 45 to control the standby state and operating state of the presser pad 42. This cylinder 46 is for retracting the slider in the contracted state, and is configured to allow free movement of the presser pad 42 integrated with the slider 45 when the contracted state is released and the cylinder 46 is released into a free state. The slider 45 receives a shift arm 48 of an actuator 47 at the rear thereof. That is, as an example, an actuator 47 unit is attached to the side surface of the substrate 35, and a shift arm 48 is attached to the force shaft thereof, and the working end of the shift arm 48 is connected to the arm support portion 49 of the slider 45. With this configuration, the slider and its integrated presser pad, which can move freely when the cylinder 46 is released from contraction, receive a forward tendency due to the rotation of the shift arm 48 of the actuator, and are always extended forward with a cushioning effect. It is structured like this.
The mechanical configurations of the workpiece holding device 1 and the sanding machine 2 have been described above, but in the present invention, the workpiece A is rotated and the sanding unit 21 is made to move forward and backward and swing. These are configured to polish the periphery of the workpiece A, and in particular, these are equipped with CNC control devices such as a numerically controlled driver box and a control box with a built-in computer, and according to the numerical values input in advance, The rotational movement of the workpiece A, the forward and backward movement of the sanding machine 2, and the swinging movement of the sanding unit 21 are automatically performed. The drive motors 14, 28 and 32 are therefore connected to a CNC control and rotate automatically. Although an example is shown in which two sanding machines 2 are symmetrically provided on the left and right sides of the holding device 1, in many cases a chamfer cutter unit is also attached to these.

Of course, like the sanding machine 2, this one is also numerically controlled.

Next, the procedure for polishing the periphery of the workpiece A will be explained. First, a program corresponding to workpiece A is input into the computer, and the sanding unit 21
Adjust your posture. This adjustment is to ensure that the polishing surface of the sanding unit 21 properly contacts the surface to be polished of the workpiece A, by moving the support post 33 left and right, raising and lowering the mounting frame 34, and moving it forward and backward. The positioning of the sanding unit 21 is further adjusted by adjusting its inclination angle. At this time, the cylinder 46 is contracted and the slider 45 is pulled back. Therefore, the presser butt 42 attached to the slider 45 is also pulled back, and the sanding belt 41 is on the straight line connecting the guide pulleys 38 and 39, even if the sanding unit 21 advances to a predetermined position. The sanding belt 41 is prevented from coming into contact with the workpiece A. Next, the workpiece A is placed on the work table 12.
The workpiece is mounted in a predetermined position and in a predetermined posture, and is held down and fixed by lowering the workpiece holding plate 15 from above. Finally, start the control device. Then, the drive motor 36 is started, the sanding belt 41 is rotated, and the drive motors 28 and 32 are also started, and the sanding unit 21 advances to a predetermined position, and the surface to be polished of the workpiece A is opposite. Subsequently, the drive motor 14 is activated to rotate the workpiece A, and the cylinder 46 is extended to advance the slider 45 to a certain position. Then, the presser pad 42 protrudes the sanding belt 41 from inside, bringing the sanding belt 41 into contact with the surface to be polished and polishing it. By the way, in this device, the contact area of the polishing surface of the sanding unit 21 with the surface to be polished is different between a straight part and a curved part of the workpiece A, and the contact area is different in the part where the radius of curvature is small. becomes narrower.
Therefore, in the portion where the peripheral edge of the workpiece A is curved, the pressing force of the presser butt 42 is adjusted in accordance with the curvature, and the pressing force per unit contact area is adjusted to prevent over-shaving in this portion. be. As a method of adjusting the pressing force, a pressure regulator is installed between a compressor (not shown) and the actuator 47, and this is connected to a control device to adjust the air pressure according to the curvature of the part to be polished, or the actuator Two or more regulators with different regulation pressures are connected in parallel to the 47, and on-off valves are attached to each, and these are further communicated with a control device to make adjustments by opening any one of the on-off valves.

(Effects of the Invention) As described in detail above, the present invention is applicable to the curved portion compared to the straight portion because the conventional profile rotary sander could not adjust the pressing force of the presser pad during the polishing operation. However, there is a problem in that the pressing force per unit area of the presser pad acting on the surface to be polished increases, resulting in over-shaving, and for this reason, it is almost impossible to perform not only grinding work but also final polishing work. This has been improved, and the pressing force of the presser pad is adjusted according to the curvature of the curved part of the periphery of workpiece A, so that the pressing force of the sanding belt against the surface to be polished is always appropriate. Therefore, efficient and good processing can be performed.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an outline of the polishing work state, FIG. 2 is a side view of the same, and FIG. 3 is a plan view showing the main parts. 1; Holding device 2; Sanding machine lO: Base 11; Boss 12; Work table 13; Rotation shaft 14; Drive motor 151 Work holding plate 16; Support frame 21; Sanding unit 22; Fixed frame 23; Movable base Board 24; Swivel frame 25; Screw 26; Male screw rod 27; R spiral 28: Motor 29; Swivel 30; Swivel shaft 31; Drive rod 32; Motor 33
; Support post 34; Mounting frame 35: Board 36; Drive motor 37; Pulley 38; Guide pulley 39; Guide pulley 40; Swivel arm 41; Sanding belt 42; Presser butt 43; Guide rail 44; Bracket 45; Slider 46 ; cylinder 4
7; Actuator 48; Shift arm

Claims (1)

[Claims] The workpiece holding device includes a workpiece holding device and a sanding machine provided near the workpiece holding device, and the workpiece holding device has a worktable connected to the base via a rotating shaft, while the sanding machine is attached to the base. A movable platform is provided so that it can move forward and backward, and a rotating pedestal is provided on the movable platform to be able to rotate freely around a pivot shaft.A pair of left and right support posts are also established on the swivel pedestal, and a mounting frame is attached to this. In a rotary sander, a sanding unit consisting mainly of a sanding belt that runs on an almost planar triangular track is attached to this mounting frame so that it can be moved forward and backward, and also up and down. A profile characterized in that the pressing force is freely adjustable according to the curvature of the curved portion of the workpiece to appropriately adjust the pressing force per unit area of the sanding belt against the surface to be polished of the workpiece. Polishing method using rotary sander.