JPS6322005Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a counterbore jig for performing counterbore processing on a workpiece.

Conventionally, as shown in FIG. 6, in order to form a counterbore portion A in a through hole H pre-drilled in a workpiece W, a step drill 20 is used to perform counterbore processing. However, as shown in the figure, the surface of the work W
In order to counterbore a through hole H that is close to the protruding part W1 of Wa from the protruding side (surface Wa side) of the protruding part W1, as the protruding part W1 becomes considerably high, the shaft 21 of the stepped drill 20 or In order to prevent interference with the chuck (not shown) of the drill body,
A stepped drill 20 with a small shaft diameter and a long shaft length is required. However, this stepped drill 20 with a long shaft length has had problems such as poor cutting performance and frequent breakage accidents.

Therefore, in view of the above-mentioned conventional drawbacks, this invention has been developed in order to form a counterbore on the surface side of the through hole for a workpiece that has a protrusion on the surface and has a through hole close to the protrusion. If it is possible to perform counterboring on the front side of the workpiece from the back side through the through hole, even if the height of the protruding part is quite high, there will be no deterioration in machinability or breakage accidents with conventional stepped drills. This method was devised with an eye to eliminating problems such as occurrence of problems, and its purpose is to counterbore the front side (the other side) of the workpiece rather than the back side (one side). It is an object of the present invention to provide a counterbore jig that can perform the following.

In order to achieve the above-mentioned object, this invention is such that a tip holder with a tip is rotatably attached to the arbor, a centrifugal force pendulum whose tip abuts against the tip holder is rotatably disposed in the arbor, This counterbore jig is configured to rotate the chip holder to the cutting position by rotating the centrifugal pendulum due to the rotation of the arbor.

An embodiment of this invention will be described below with reference to FIGS. 1 to 5. Figure 1 shows the left side of the counterbore jig, Figure 2 shows the same plane, and - in Figure 1.
In FIG. 3, which shows a line cross section, a bifurcated portion 2 that opens in the vertical direction is formed at the front portion of the arbor 1. The rear part of the arbor 1 is equipped with a rotating device, e.g.
It is attached to the spindle (not shown) of the NC machine tool. A chip holder 3 is rotatably attached to the bifurcated portion 2 of the arbor 1 with a pin 4. The front end of the tip holder 3 protrudes from the front end of the arbor 1, and a square tip 5 is exchangeably fixed to the front end with screws 6. This chip 5
The rear upper corner portion is the cutting portion 7. A U-shaped bracket 8 is fixed to the base of the bifurcated portion 2 of the arbor 1 by welding or the like with its opening facing upward. The bottom part 9 of the bracket 8 is the arbor 1
By straddling the bifurcated portion 2 of the tip holder 3
It comes into contact with the rear end portion 10 to prevent the holder 3 from rotating counterclockwise (counterclockwise in FIG. 1) (see FIG. 5). As shown in FIG. 5, when the rear end 10 of the tip holder 3 comes into contact with the bottom 9 of the bracket 8,
The tip holder 3 is in the cutting position. A centrifugal pendulum 11 is rotatably attached to the upper part of the bracket 8 with a pin 12. The centrifugal pendulum 11 has a weight portion 13 at its rear end, and the weight portion 13 rests on the arbor 1 when the arbor 1 is not rotating.
At the tip 14 of the centrifugal pendulum 11, the rear end 10 of the tip holder 3 is attached to the tip holder 3 centered on the pin 4.
They are in contact due to the moment difference between the front and rear. In this state, the chip holder 3 is in the standby position. At the tip 14 of the centrifugal force pendulum 11, the rotation of the arbor 1 causes the pendulum 11 to rise by an angle θ1 in the radial direction of the arbor 1 around the pin 12, thereby moving the tip holder 3 in a counterclockwise direction around the pin 4. In order to rotate the tip holder 3 by an angle θ2 and to hold the rear end 10 of the holder 3 between it and the bottom 9 of the bracket 8, an arcuate shape abutting against the upper surface 15 of the rear end 10 of the tip holder 3 is formed. A guide surface 16 is formed (see FIGS. 4 and 5). Note that the angle θ1 changes as the rotation of the arbor 1 decreases or stops.
The angle is set such that the centrifugal pendulum 11 returns to its original state due to a moment difference between the front and back about the pin 12. Further, a positioning ring 17 is fixed to the rear end of the arbor 1 with screws 18 so as to be axially movable. By adjusting the position by axially moving the ring 17, the attachment length of the arbor 1 to the spindle of the rotating device is appropriately selected.

An example of counterbore processing using the above-mentioned counterbore jig will be described. As shown in FIG. 1, with the chip holder 3 in the standby position, the arbor 1 is advanced through the spindle of the rotating device, and the chip 5 is inserted into the through hole H of the workpiece W from the back side Wb side to the front side Wa side. (See Figure 4). Next, when the arbor 1 is actively rotated by a rotating device, the centrifugal pendulum 11 rises in the radial direction of the arbor 1 around the pin 12, and the chip holder 3 is rotated around the pin 4 and held at the cutting position. be done. In this state, by retracting the arbor 1 via the spindle of the rotating device, the chip 5 is moved to the workpiece W.
The edge of the surface Wa side of the through hole H is cut to form a counterbore part A (see Fig. 5). After cutting is completed,
After moving the arbor 1 forward again, the rotation of the arbor 1 is stopped, and the centrifugal pendulum 11 is positioned above the arbor 1. In addition, when arbor 1 stops,
So that the centrifugal pendulum 11 is positioned above the arbor 1,
It is a good idea to add an orientation function to the rotating device. By positioning the centrifugal pendulum 11 on the arbor 1, the chip holder 3 returns to its original standby position. In this state, move arbor 1 back again,
The chip 5 is passed through the through hole H to the back side. Through the above procedure, the workpiece W is counterbored.

In the above embodiment, the counterbore jig was moved relative to the workpiece W by moving the spindle of the rotating device back and forth, but it is also conceivable to move the workpiece W relative to the counterbore jig.

According to the counterbore jig described above, the back surface of the work W
Since it is possible to perform counterboring on the surface Wa side rather than on the Wb side, it is especially suitable for work W as shown in Fig. 4.
There is a protrusion W1 on the surface Wa, and the protrusion W1
It is suitable for performing counterboring in close proximity to. In other words, in conventional stepped drills, if the protruding portion W1 of the workpiece W near the counterbore portion A is quite high, problems such as deterioration of the cutting performance of the stepped drill and occurrence of breakage accidents will occur. However, with this counterbore jig, counterboring can be performed without being affected by the height of the protruding portion W1 of the workpiece W. In addition, conventionally, it was sometimes necessary to invert the front and back surfaces Wa and Wb of the workpiece W when machining the through hole H of the workpiece W and counterbore it, but with this counterbore jig, The through-hole H machining and counterbore machining of the workpiece W are performed from the back surface Wb of the workpiece W.
This can be done without reversing, and it is also possible to improve work efficiency.

That is, according to this invention, with the chip holder rotatably attached to the arbor in the standby position, insert the chip of the chip holder into the through hole of the workpiece from the back side (one side) to the front side (the other side). After passing through the hole, the arbor is actively rotated and the chip holder is held in the cutting position by the rotation of the centrifugal force pendulum, thereby making it possible to counterbore the surface side of the through hole. This eliminates the disadvantages of conventional stepped drills, especially the deterioration of machinability and breakage accidents of stepped drills used for counterboring when the protruding part near the counterbore of the workpiece is quite high. It is effective for In addition, this counterbore jig is
Needless to say, the present invention can also be used for workpieces having shapes other than workpieces having a protrusion close to the counterbore.

[Brief explanation of the drawing]

Figures 1 to 5 show an embodiment of this invention, in which Figure 1 is a left side view of the counterbore jig, Figure 2 is a plan view of the same, and Figure 3 is taken along the - line in Figure 1. A cross-sectional view, Fig. 4 is a partially broken left side view showing the counterbore jig in front of the arbor, Fig. 5 is a left side view showing the counterbore jig during counterbore processing, and Fig. 6 shows a conventional example. FIG. 1... Arbor, 3... Chip holder, 5... Chip, 11... Centrifugal pendulum.

Claims (1)

[Scope of utility model registration request] A chip holder equipped with a chip is rotatably attached to the arbor, and a centrifugal force pendulum whose tip abuts against the chip holder is rotatably arranged in the arbor. A counterbore jig characterized in that it is configured to rotate to a cutting position.