JPH0344438Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement in a feeding mechanism of, for example, an electric angle chisel.

Generally, in a machine that employs a feed mechanism using a feed screw, it is necessary to absolutely stop the machine at the limit of the feed amount so as not to damage the main body. In addition, in devices where the feed screw is rotated by the power of the motor section via a deceleration mechanism, the motor and rotating body try to continue rotating the feed screw due to inertia force, so it is necessary to apply a brake in some way. .

A conventional feed mechanism will be described in the case of an electric angle chisel employing an automatic feed mechanism using a screw, with reference to FIGS. 1 and 2. FIG. 1 is a partially sectional front view, and FIG. 2 is a circuit diagram. In the figure, two columns 4, 4 are installed on a base 3, and the other ends of the columns 4, 4 are connected by a bridge 2. Reference numeral 5 denotes a motor section containing a motor (not shown), which is slidably attached to the columns 4, 4. Reference numeral 1 denotes a feed screw, which is fixed to the bridge 2, screwed into a female screw, driven by a motor, and attached to the motor section 5. Reference numeral 6 is a corner-only cutter fixed to the motor section 5, 7 is a limit ball that is set on the base 3 and comes into contact with the micro switch MS1 fixed to the motor section 5 when the motor section 5 approaches, and 8 is a bridge 2. This is a limit pole that is erected in the motor section 5 and comes into contact with the micro switch MS2 fixed to the motor section 5 when the motor section 5 approaches. Further, SW1 is a main switch, SW2 is a vertical movement changeover switch, A is a rotor, B is a brake coil, and S is a stator coil.

When the feed screw 1 is rotationally driven by the motor, the motor portion 5 is guided by the columns 4 and 4 and moves in the vertical direction. The vertical feed amount is set to be slightly larger than the effective length of the blade 6 attached to the motor section 5. Figure 2 shows that switch SW2 is switched to the forward rotation side in the state shown in Figure 1.
It also shows a state in which drilling has started with switch SW1 closed. Motor section 5 due to forward rotation of the motor.
When the motor unit 5 begins to descend, the switch MS2 is removed from the pole 8, and the switch MS2 is switched to the position shown by the chain line in FIG. 2, and in this state, the motor unit 5 continues to descend. When the motor section 5 reaches the lower end position shown by the chain line in FIG. 1, the switch MS1 contacts the pole 7,
As a result, the switch MS1 is switched to the position shown by the chain line in FIG. This opens the power supply circuit and forms a closed circuit between the rotor A and the brake coil B, and the rotor A is braked by dynamic braking, stopping the motor instantly. As a result, the feeding of the motor section 5 is stopped. In this state, switch SW
2 to the reverse side, switch SW2 switches to the second
The state changes to the state shown by the chain line in the figure. As a result, the connection relationship between the stator coil S and the rotor A is reversed from that during normal rotation, the brake circuit is opened, the motor is rotated in reverse, and the motor section 5 is raised. At the start of the upward movement, the switch MS1 is detached from the pole 7 and switches from the connection relationship shown by the chain line in FIG. When this point is reached, stitch MS2 is operated by pole 8, resulting in the connection shown by the solid line in Figure 2, and as before, dynamic braking is activated and the motor stops instantly.
The motor section 5 stops rising.

According to the above conventional structure, the micro switch
There are many parts required to stop the motor section 5, such as MS1, MS2, limit balls 7, 8, and brake coil B, and furthermore, the operation of the brake circuit composed of brake coil B and rotor A is limited to rotation. There are problems such as poor contact between the commutator of child A and the carbon brush, which may prevent the brake from being applied, resulting in low reliability.

The present invention was devised in view of the above situation, and aims to provide a feed mechanism that has a simple structure, can reduce the number of parts, and can reliably stop the motor section.

The feeding mechanism of the present invention includes a plurality of columns with one end planted on a base and the other end connected via a bridge, a motor section slidably attached to the columns, and an internal thread provided on the bridge. a feed screw that is screwed into the feed screw and is driven by the motor of the motor section, and a small diameter that is formed at both ends of the feed screw so that the feed screw is disengaged from the female thread. a guide portion, a supporter plate that is slidable in the axial direction, restrains the female screw in the rotational direction, and holds the female screw on the bridge; and elastic members loosely fitted in the column and disposed between the motor section and the bridge, and between the motor section and the base, respectively.

Hereinafter, the feed mechanism of the present invention will be described as an embodiment, and the same parts as those of the conventional one will be denoted by the same reference numerals, and the explanation of the structure of the same parts will be omitted, and the case of an electric angle chisel will be explained with reference to FIGS. 3 to 5. FIG. 3 is a circuit diagram, and FIGS. 4 and 5 are operation explanatory diagrams, respectively. In the figure, the feed screw 1 is smoothly chamfered at the beginning and end of thread cutting, and small diameter guide portions 9 and 10 with a diameter slightly smaller than the thread root diameter are formed at both upper and lower ends of the effective length, respectively. has been done. In addition, in FIG. 6 showing details of part A in FIG. 4 and FIG. 7 showing a bottom view of FIG. 13, it is housed in a recess of the bridge 2 and is mounted so as to be movable a distance l in the axial direction. A compression spring 16 loosely fitted around the outer periphery of the female thread 14 is installed between the flange 14a of the female thread 14 and the bridge 2.
At the beginning and end of thread cutting, chamfers are formed at the same angle as the chamfers formed at the beginning and end of thread cutting of the feed screw 1. Further, a compression spring 15 is loosely fitted to the column 4 and is attached between the motor section 5 and the base 3, and a compression spring 17 is similarly attached between the motor section 5 and the bridge 2. As shown in Fig. 3, the power supply circuit is composed of a main switch SW1 and a vertical movement changeover switch SW2.
By switching SW2, the rotor A is rotated forward or reverse.

When processing the wood 18 with this electric angle chisel, add the wood 18 between the base 3 and the vise 11, set the vertical movement changeover switch SW2 to "down",
When the main switch SW1 is turned on, the feed screw 1 rotates, the motor section 5 moves, and a square hole is machined by the cutter 6. At this time, the female thread 14 is the feed screw 1.
Due to the reaction force, the distance l shown in FIG. 6 becomes 0, the upper end contacts the bridge 2 and bears the load, and the compression spring 16 becomes compressed. When the motor part 5 is fed close to the lower limit, it comes into contact with the compression spring 15 and receives a force in the opposite direction, so that the inertial force of the motor part 5 is absorbed, and as shown in FIG. 14 is disengaged, the compression spring 15 pushes the feed screw 1 toward the female screw 14, and the compression spring 16 presses the female screw 14 toward the feed screw 1, causing the chamfers of both to be pressed together. It is touching and slipping at the part, and the feed is definitely stopped. At this time, the central axes of the feed screw 1 and the female thread 6 are kept in alignment by the small diameter guide portion 9 of the feed screw 1.

When the motor section 5 is to be raised, the rotation of the motor is reversed using the vertical movement changeover switch SW2, and the rotation of the feed screw 1 is reversed and engages with the female thread 14 again, so that the lower end surface of the female thread 14 is connected to the support plate. The motor section 5 rises by contacting the lower end surface of the motor section 13. When the motor section 5 is fed to the upper limit, the feed screw 1 and the female screw 14 are disengaged again as shown in FIG. Set screw 14
contact at the chamfered portions of both, and sliding feed is reliably stopped. At this time as well, the centers of the feed screw 1 and the female thread 14 are kept aligned by the small diameter guide portion 10 of the feed screw 1. Then, when the work is finished, open the main switch SW1. Incidentally, the contact chamfered portions of the feed screw 1 and the female screw 14 at both the upper and lower limit portions are hardened to have high wear resistance. In addition,
In the case of a small feeding load, the above-mentioned hardening is not necessarily required.

In this way, the feed mechanism of this embodiment reliably stops the feed by disengaging the feed screw driven by the motor at both ends of the feed and the female thread that engages with this feed screw, improving reliability. When the screw rotates and engages again, the tension of the compression spring allows for smooth engagement, and the structure is simpler than the conventional one, reducing the number of parts.

Although the above embodiment uses a spring to promote engagement between the feed screw and the female screw after the rotation direction is reversed, the same effect can be obtained by using an elastic body such as rubber. Furthermore, if the motor section is sufficiently heavy and the feed screw and the female thread engage again without pushing down the motor section at the upper limit with the compression spring, the same effect can be obtained even without the compression spring.

As described above, the feed mechanism of the present invention has a simple structure and can reduce the number of parts, and also has the effect of ensuring that the motor part stops, improving reliability, and allowing smooth engagement even when the threaded rod is reversed and engaged. It is.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a part of the feed mechanism of a conventional electric angle chisel in cross section, Fig. 2 is a circuit diagram of Fig. 1, and Fig. 3 is a circuit diagram of an embodiment of the feed mechanism of the present invention. , Fig. 4 and Fig. 5 are respectively explanatory diagrams of operation, Fig. 6 is a detailed view of section A in Fig. 4, and Fig. 7 is a detailed view of section A in Fig.
FIG. 3 is a bottom view of the figure. 1...Feed screw, 2...Bridge, 3...Base, 4...Column, 5...Motor part, 9, 10...
...Small diameter guide part, 13...Support plate, 14
...Female thread, 14a...Flange, 15, 16,
17... Compression spring.

Claims (1)

[Scope of utility model registration request] A plurality of columns with one end planted on a base and the other end connected via a bridge, a motor part slidably attached to the column, and the motor part screwed into an internal thread provided on the bridge. a feed screw driven by a motor, the feed screw having a small diameter guide portion formed at both ends of the feed screw so as to disengage the feed screw from the female thread; a supporter plate that is slidable in the axial direction, restrains the screw in the rotational direction, and holds the screw on the bridge; an elastic member that is disposed between the flange of the female screw and the bridge and loosely fitted around the outer periphery of the female screw; A feeding mechanism characterized in that an elastic member is provided, which is loosely fitted into the column and arranged between the motor section and the bridge, and between the motor section and the base.