JPH08317940A - Centerless grinder for fine tip processing of very thin medical treatment member - Google Patents

Abstract

PURPOSE: To make it possible to execute taper processing with a prescribed accuracy in taper processing of very thin member, wherein a workpiece can be unloaded automatically once the taper processing has been finished. CONSTITUTION: A centerless grinder having a grinding stone 1, a controlling stone 11, and a receiving plate 12 placed between the former two parts to support a workpiece 4, wherein a push-in member to push in positively the workpiece 4 between the grinding stone and the controlling stone along the receiving plate 12, and a workpiece discharging notch 11b having depth greater than the diameter of the workpiece 4 on the outer circumference of the controlling stone 11 are disposed. When the controlling stone 11 rotates to pick up the workpiece 4 between a notch end P2 and the grinding stone 1, grinding operation starts, and is finished when a notch end P1 comes to the workpiece position. The workpiece 4 drops down at P1 into the notch 11b, and into a box 13 where ground workpieces are stored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centerless process for tapering an extremely fine round bar work having a diameter of 1 mmφ or less, such as a dental broach.

[0002]

2. Description of the Related Art In order to manufacture a broach for dental use, first, an extra-fine round bar (extra-fine material) having a length of about 50 mm and a diameter of 1 mmφ or less is made. Is tapered to about 0.1 mmφ. The extra-fine material is used as a smooth round type brooch in this as-fabricated state, or a part of the tapered portion is made into a prismatic shape to form a smooth angle type brooch, or a large number of tapered portions are used. The barbed type brooch is formed by forming a sting.

The spine type cleanser type is used for inserting into the pulp or root canal and hooking and removing the residue inside. On the other hand, the smooth type is used for winding a Watte around the tip and inserting it into the pulp or the root canal to allow the Watte to remain inside or to find the direction of the root.

The present invention relates to a technique of tapering an ultrafine material in the above manufacturing process. A centerless grinder has been conventionally used for this processing. The outline will be described with reference to the drawings. In this specification, since it is necessary to explicitly describe the ultrafine material, the relationship of the size of each part shown in each drawing is made to be quite different from the actual one.

In FIG. 5, 1 is a grinding wheel, 2 is a control wheel, 3 is a receiving plate, and 4 is a work made of a very fine round bar. The grinding wheel 1 and the control wheel 2 have the same shape and the outer diameter is changed in the same direction by the same size. The grinding wheel 1 rotates at high speed in the direction of the arrow in the figure, and the control wheel 2 rotates very slowly in the direction of the arrow.
Further, the control grindstone 2 is movable in the direction of arrow a or b in the figure, and the interval between the grindstone 1 and the grindstone 1 can be changed.

With the control grindstone 2 moving in the direction a to widen the gap between the grindstone 1 and the work piece 4 made of a very fine material.
Is placed on the receiving plate 3 at a position where the tip of the receiving plate 3 contacts the stopper 5 attached to the receiving plate 3, that is, at a position where the entire portion to be tapered faces the grinding wheel 1. Next, the control grindstone 2 is moved in the direction of the arrow b to press the work 4 against the grindstone 1. The work 4 rotates in the direction of the arrow while being braked by the control grindstone 2, and is ground by the difference in surface speed with the grinding grindstone 1. When the tapering process is completed, the control grindstone 2 is moved again in the direction a, and the work 4
Take out.

In the above method, the amount of tapering is determined by the moving distance of the control grindstone 2 in the b direction,
In order to improve the processing accuracy, it is necessary to keep the moving distance of the control grindstone 2 constant with high accuracy. However, this is very difficult because the work is very thin. Also, the work 4 should be supported by a robot arm or the like and placed on the receiving plate 3 or taken out.
Since the work itself is thin and the backing plate is thin, it is difficult to place it well. Further, the work 4 is too thin to be grasped well, or because the work 4 is below the axis of the grindstones 1 and 2, it is easy for the work 4 to touch the grindstones 1 and 2 during movement.
There were many problems such as the work 4 could not be recognized due to the grinding oil, and the use of the robot arm was not successful.

On the other hand, there is known a method of tilting the control grindstone 2 with respect to the grinding grindstone 1 by a small angle as shown in FIG. With such a structure, when the tip of the work 4 is sandwiched between the grinding wheel 1 and the control grindstone 2 and the grinding is started, the work 4 naturally winds in the direction of the arrow c in FIG. 5B. (Or be pulled in). Therefore, when the tip of the work 4 comes into contact with the stopper 5, the control grindstone 2 may be moved in the a direction to take out the work 4.

However, even in this case, the diameter of the work 4 itself is 0.8 mmφ before machining, which is very small, and the tip diameter (3 mm from the tip) is 0.13 because it is tapered.
The diameter is further reduced to 0.3 mm mm to 0.32 mm, and when it comes into contact with the stopper 5, the tip of the work 4 is easily bent, and the length to be tapered cannot be maintained accurately. Even if it is attempted to control the rotational speed of the control grindstone 2 without using the stopper 5, it is difficult to keep the length of the tapered portion constant. If the length of the tapered portion is different, the diameter of the tip is also different, and the broach or the like is not in a constant shape.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and it is an object of the present invention to provide a centerless grinder capable of performing a predetermined length of taper in the ultrafine taper processing. I am trying.

Another object of the present invention is to provide a centerless grinder capable of automatically taking out a work after finishing the tapering process for an ultrafine material. Still another object of the present invention is to provide a centerless grinder which can perform tapering with a predetermined accuracy in tapering of an ultrafine material and can automatically take out a work after the tapering is finished.

[0012]

SUMMARY OF THE INVENTION In order to provide a centerless grinder capable of tapering a predetermined length, the present invention provides a grinding wheel for machining, a control wheel,
It is applied to a centerless grinder having a receiving plate that supports the work between them, and between the grinding wheel and the control whetstone along the receiving plate, a pressing member that positively pushes the work is provided. It is characterized in that it is provided, and when the pushing member pushes the work into a predetermined distance, the grinding process is finished.

Further, in order to provide a centerless grinder capable of automatically taking out a work after the tapering process for an extra fine material is finished, the present invention provides a notch for discharging a work on the outer peripheral surface of the control grindstone, the work being larger than the thickness of the work. Is characterized by the formation of. In this case, it is desirable to additionally provide the above-mentioned pushing member.

Further, in order to provide a centerless grinder capable of performing a tapering process with a predetermined accuracy in the tapering process of an ultrafine material and automatically taking out a work after the tapering process is completed, the present invention has the above-mentioned structure. It is characterized in that it is provided with an interlocking device for synchronizing the advance / retreat of the pushing member and the rotation of the control grindstone.

[0015]

Embodiments of the present invention will be described with reference to the drawings. FIG.
3 to 3 are diagrams showing the configuration of the first embodiment of the present invention.
In these figures, 1 is a grinding wheel, which is the same as the conventional example. Reference numeral 11 is a control grindstone, and a half or more of the circumference is a circular arc portion 11a for pressing the work 4 against the grinding grindstone 1 as in the conventional case, and the remaining a little less than 1/2 is a notch portion 11b. The notch 11b has a shape in which a small-diameter circular arc and the outer circumference 11a are connected by a radial line at one end P1 and a tangential line at the other end P2, and the depth D of the notch 11b is
It is larger than the thickness (diameter) of the work 4. Reference numeral 12 is a receiving plate having a flat top portion and having arcuate or linear slopes corresponding to both grindstones on both sides and connected to a wide base portion. Reference numeral 13 is a box for accommodating the work 4 for which the tapering process has been completed.

The control grindstone 11 is one work 4
Every time you grind, it will rotate exactly once,
A cylindrical cam 14 concentric with the rotating shaft is provided at the center. Reference numeral 15 in FIG. 3 is a drive lever, one end of which is a shaft 15a.
It is rotatably fixed in and has a long hole 15b at the other end. Further, a cam follower 15c is provided in the middle of the drive lever 15, and is in contact with the cam surface 14a of the cylindrical cam 14.

Reference numeral 17 is a bed of a centerless grinder, which has a guide groove 18 at the center toward the gap between the grinding wheel 1 and the control wheel 11, and this guide groove 18
A push member 19 is slidably fitted in the. A pin 19a is erected on the pushing member 19, and the pin 19a
Is slidably inserted in the long hole 15b of the drive lever 15. At the left end of the guide groove 18 in the drawing, a pressing spring 21 for urging the pressing member 19 to the right side of the drawing is provided. With the above configuration, as the control grindstone 11 rotates,
The cam follower 15c moves in the left-right direction in FIG. 3 along the cam surface 14a to rotate the lever 15 about the shaft 15a, expands the displacement amount of the cam surface 14a, and transmits the displacement amount to the pushing member 19. Push the guide member 1 into the guide groove 1 as indicated by the arrow.
Move back and forth along 8.

In the above structure, the cylindrical cam 14
A cam follower 15c guided by the cam surface 14a of the cylindrical cam, and a drive lever 15 provided with the cam follower.
And constitute an interlocking device that associates the movements of the control grindstone 11 and the pressing member 19.

Reference numeral 22 is a device for supplying the work 4, which has a guide groove 23 having a width substantially equal to the length of the work 4, and a feeding block 25 sliding in the guide groove 23. A large number of works 4 are put in the guide grooves 23, and the works 4 are sent one by one to the front surface (right side in FIG. 3) of the pushing member 19 by the sending block 25.

Next, the operation of the centerless grinder for tapering the work 4 will be described with reference to FIGS. 1 to 3. First, one work 4 is supplied from the supply device 22 to the front surface of the pushing member 19. The grinding wheel 1 is rotating at high speed, and the control wheel 11 is also slowly rotating in the direction of the arrow in FIG. 1 or 2. Control grindstone 11
Since the cylindrical cam 14 also rotates with the rotation of, the cam follower 15c moves along the cam surface 14a in the direction of the rotation axis of the grindstone. By this movement, the pushing member 19 moves the work 4 toward the gap (grinding position) between the grinding wheel 1 and the control wheel 11.

When the tip of the work 4 reaches the grinding wheel 1,
As shown in FIG. 2A, the work 4 comes into contact with the notched end portion P2 of the control grindstone 11 and is pressed against the grinding grindstone 1 to start grinding. The pushing member 19 continues pushing the work 4 and advances to the right side of FIG. When the control grindstone 11 is inclined with respect to the grinding grindstone 1 as described with reference to FIG. 6, the control grindstone 11 naturally squeezes without being pushed by the pushing member 19. However, in the present invention, the pushing member 19 has the winding speed. The shape of the cam surface 14a of the cylindrical cam 14 is formed so that the work 4 is pushed in at a higher speed. However, the control wheel 11 is the grinding wheel 1
Even if it is not inclined with respect to
Since it suffices to push in the work piece 4, it is sufficient that the pushing member 19 positively pushes in the work 4. By positively pushing the work 4, the pushing length of the pushing member 19 can be made constant, and the length of the work 4 to be tapered can be aligned with high accuracy.

When the grinding by the grinding wheel 1 proceeds while being pushed by the pushing member 19 and the grinding of the work 4 with a predetermined length and a predetermined taper is completed, the control grindstone 11
The notched end portion P1 of the workpiece reaches the work 4, the force holding the work 4 is lost, and the work 4 becomes free and falls, and is housed in the box 13. At this time, the flow of the grinding fluid is the work 4
Help to drop. The control grindstone 11 continues to rotate slowly, and the feeding device 22 moves the new work 4
Is supplied to the front surface of the pushing member 19, and the above operation is repeated. Since the rotation angle of the control grindstone 11 and the pushing amount of the pushing member 19 are synchronized with each other, the length of the work 4 subjected to the tapering process is accurately constant. Further, since the control grindstone 11 does not move in the a and b directions as shown in the conventional example of FIG. 5, the grinding amount becomes constant and the diameters of the tips of the tapered portions are aligned with high accuracy.

FIG. 4 shows a second embodiment of the present invention. The present embodiment and the first embodiment are the same except for the interlocking device portion. That is, in this embodiment, the cylindrical cam 14 and the drive lever 15 are not provided, but the rotary encoder 28 and the actuator 29 are provided instead. The rotary encoder 28 measures the rotation angle of the control grindstone 11. The actuator 29 moves the pushing member 19 back and forth at a speed corresponding to the rotation angle indicated by the rotary encoder 28 according to a program input in advance.

One work 4 from the supply device 22 (FIG. 3)
When is supplied to the front surface of the pushing member 19, the actuator 29 drives the pushing member 19 to push the work 4 toward the grinding position between the grinding wheel 1 and the control wheel 11.
When the tip of the work 4 comes into contact with the grinding wheel 1, the notched end P2 of the control grindstone 11 comes into contact with the work 4 to start grinding. As the grinding progresses, the pushing member 19 positively pushes the work 4. Eventually, when the notched end P1 of the control grindstone 11 reaches the work 4, the work 4 falls and is housed in the box 13. On the other hand, the pushing member 19 retracts and returns to the initial position.

In the above embodiment, it is possible to employ a structure in which only the pressing member 19 is used, the control grindstone 11 has a conventional shape without the notch 11b, and the control grindstone 11 is moved in the directions of arrows a and b in FIG. Even with such a configuration, if the distance by which the pressing member 19 presses the work 4 is made constant, the length of the work 4 to be tapered can be kept constant with high accuracy.

Further, even if the control grindstone 11 has a shape having the cutout portion shown in FIG. 1 and the pushing member is omitted, the work after the tapering process is completed can be easily discharged. Moreover, since the control grindstone 11 does not move, the tapered shape applied to the work 4 can be made uniform with a certain degree of accuracy.

[0027]

According to the present invention as described above,
A pressing member that positively pushes the work at a speed faster than the winding speed is provided, and when the pushing member pushes the work a predetermined distance, the grinding process is finished, so the length of the work to be tapered can be accurately determined. Can be aligned with.

If the notch is formed in the control grindstone, the work can be reliably taken out after the grinding is completed. Further, since it is not necessary to move the control grindstone toward or away from the grinding grindstone, the structure of the centerless grinder can be simplified and the precision of the tapering process can be improved.

With the structure having both the pushing member and the notch, it is possible to obtain a product in which the length of the fine point for the work of the ultrafine material is uniform and the tapered shape is uniform. If the interlocking device for synchronizing the pressing member and the rotation of the control grindstone is provided, the processing accuracy can be further improved.

[Brief description of drawings]

FIG. 1 is a view showing a first embodiment of a centerless grinder for tapering an ultrafine material according to the present invention, and is a view seen from II in FIG.

2A is a diagram showing the position of a control grindstone at the start of grinding, and FIG. 2B is a diagram showing the position of a control grindstone at the end of grinding.

FIG. 3 is a plan view showing the configuration of the first exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of an interlocking device in a second embodiment of the present invention.

5A and 5B are diagrams showing a schematic configuration of a conventional centerless grinder for tapering an ultrafine material, in which FIG. 5A is a front view and FIG. 5B is a plan view.

FIG. 6 is a view showing a state in which a control grindstone is attached to be inclined with respect to a grinding grindstone.

[Explanation of symbols]

 1 Grinding Wheel 11 Control Wheel 11b Notch 12 Receiving Plate 14 Cylindrical Cam 15 Drive Lever 15c Cam Follower 28 Rotary Encoder 29 Actuator

Claims (3)

[Claims] 1. A centerless grinder having a grinding wheel for processing, a control grindstone, and a backing plate for supporting a work, which is located between the grinding whetstone and the control whetstone. A centerless grinder for fine processing of medical ultrafine material, characterized in that a pressing member for positively pressing is provided between and, and when the pressing member presses the work by a predetermined distance, the grinding process is finished. 2. A centerless grinder having a grinding wheel for processing, a control grindstone, and a backing plate between them for supporting a work, wherein a depth equal to or larger than the thickness of the work is provided on an outer peripheral surface of the control grindstone. A centerless grinder for tapering a medical ultrafine material, characterized in that a notch for discharging a work is formed. 3. The centerless grinder for tapering of an ultrafine material for medical use according to claim 1, further comprising an interlocking device for synchronizing the advance / retreat of the pushing member and the rotation of the control grindstone.