JPH0447870Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switch for controlling the speed of, for example, an electric tool, and relates to an improvement of a switch device having a movable contact piece, a common terminal, and first and second fixed terminals.

FIG. 1 shows a well-known switch device, where 1 is a box and 2 is a cover. A common contact piece 3, a first fixed contact piece 4, and a second fixed contact piece 5 are arranged at the inner bottom of the box 1 located at the front in the figure. A shaft portion 7 of an operator 6 for driving a movable contact piece, which will be described later, is provided on the cover 2 so as to be freely retractable. This shaft part 7
A coil spring 16 is interposed between the end surface of the cover 2 and the inner wall surface of the cover 2, and the operator 6 is biased in the projecting direction. The shaft portion 7 is provided with a cavity 8,
The movable contact piece 9 is stored. The shaft portion 7 is also provided with a pocket portion 10, and an ear-shaped protrusion 11 is engaged with one end of the movable contact piece 9.
In the state shown in FIG.
is in contact with the surface 13 of the pocket portion 10. On the other hand, on the surface 14 provided in the box 1,
A surface 15 provided on the movable contact piece 9 is in contact with the movable contact piece 9. The other end of the movable contact piece 9 is always urged toward the inner bottom of the box 1 by a spring 20.

The common contact piece 3 is connected to a power source 17, and the first fixed contact piece 4 is connected to a second fixed contact piece 5 and a motor 19 via a control circuit 18 consisting of, for example, a thyristor and a sliding variable resistor. connected to.

In the above configuration, when the operator 6 is driven in the direction of arrow A in the figure, the other end of the movable contact piece 9 comes into contact with the first fixed contact piece 4, and the power source 17 is supplied to the motor 19 via the control circuit 18. be done. In this state, when the operator 6 is further driven in the direction of arrow A, the resistance value of the sliding variable resistor is varied, the conduction angle of the thyristor is controlled, and the rotational speed of the motor 19 is increased. Then, when the other end of the movable contact piece 9 slides into contact with the second fixed contact piece 5, maximum power is supplied to the motor 19.

By the way, in the above structure, since the thickness direction of the movable contact piece 9 is used as the contact surface with the first and second fixed contact pieces 4 and 5, a large contact surface cannot be secured, and the temperature rise is high. ing. Moreover, as shown in Figure 1,
To turn the switch device off, spring 2
The biasing force of the coil spring 16 is required to resist the biasing force against the movable contact piece 9 of 0, and the coil spring 16 is structurally quite strong. However, since the switch device is manually operated, the coil spring 16 cannot be made very strong, so the spring 20 is weak, and the contact pressure of the movable contact piece 9 against the first and second fixed contact pieces 4 and 5 is weak. It is difficult to improve vibration resistance.

FIG. 2 shows a well-known switch device, where 30 is a box and 31 is a cover. A common contact piece 32 and a first
A fixed contact piece 33 and a second fixed contact piece 34 are provided. The cover 31 is provided with a shaft portion 36 of an operator 35 that drives a movable contact piece, which will be described later, so as to be freely retractable. A coil spring 37 is interposed between the end surface of the shaft portion 36 and the inner wall surface of the cover 31, and the operation element 35 is biased in the projecting direction. The inside of the box 30 is partitioned by a partition wall 38.
Further, a sliding resistance (not shown) is provided on the back surface of the partition wall 38.

The common contact piece 32 has two protrusions 39 formed at one end in the direction of the plane of the paper. Further, the common contact piece 32 is provided with a movable contact piece 40 . A recess 41 is provided approximately in the middle of the movable contact 40, and an actuator 42 is engaged with the recess 41. The base end portion of the actuator 42 is fitted into a recess 43 provided in the shaft portion 36 of the operator 35 so as to be freely protrusive and retractable.
is biased in the projecting direction by a coil spring 45 interposed within the recess 43 and the recess 44 of the actuator 42. Note that the common contact piece 32 and the first and second fixed contact pieces 33 and 34 are connected to the control circuit 1 as in FIG.
8, a power source 17 and a motor 19 are connected.

By the way, in the above configuration, compared to FIG.
The first and second fixed contact pieces 33 and 34 of the movable contact piece 40
This is advantageous in terms of temperature rise because the contact surface is the plate surface. However, by providing a recess 41 in the movable contact piece 40 and engaging the actuator 42 containing a coil spring 45 in this recess 41,
The structure for moving the movable contact piece 40 is such that the outer diameter of the coil spring 45 is increased to improve vibration resistance, and the outer diameter of the actuator 42 is therefore increased.
The dimension of 0 in the direction perpendicular to the paper surface must be increased. As a result, the size of the switch device in the direction perpendicular to the plane of the paper must be increased, making it difficult to downsize the switch device.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, form a large approximately L-shape at one end of the movable contact piece, and move the movable contact piece with a pocket provided in the shaft, thereby reducing temperature rise. The purpose is to provide a switch device that is small in size and has excellent vibration resistance.

In the present invention, the shape of the movable contact piece has been devised in order to suppress temperature rise, make the switch device small, and have excellent vibration resistance.

In FIG. 3, 50 is a switch device;
Reference numerals 1 and 52 denote a box and a cover, respectively, constituting a switch case. A shaft portion 54 of an operator 53 is provided on the cover 52 so as to be freely retractable. A return spring 55 is interposed between the end surface of the shaft portion 54 and the inner surface of the cover 52, and the spring 55 urges the operator 53 and the shaft portion 54 in the projecting direction. The shaft portion 54 is provided with a locking means 56, and this means 56 engages with a protrusion 57 provided on the inner surface of the cover 52 to define the protruding position of the operator 53.

On the other hand, the inside of the box 51 is partitioned by a partition wall 58, and the box 51 located at the front in the figure
The common terminals 5 are arranged sequentially along the longitudinal direction on the inner bottom of the
9. First and second fixed terminals 60 and 61 are provided with a predetermined distance between them. Furthermore, a sliding variable resistor (not shown) is provided on the back surface of the partition wall 58.

A fulcrum member 62 is connected to the common terminal 59 (one member may be used). Further, a movable contact piece 63 is provided on the common terminal 59. The movable contact piece 63
One end portion 64 is bent into a large, substantially L-shape, and the other end portion 65 is bent into a small, substantially L-shape. On the other hand, the shaft portion 54 is provided with a pocket 66, and the pocket 66 has walls 67, 68. One end 64 of the movable contact piece 63 is housed in the pocket 66 . Further, a recessed hole 69 is provided in the shaft portion 54, and a substantially middle portion of the movable contact piece 63 is inserted into the recessed hole 69 and a recessed hole 72 provided in the actuator, which will be described later. coil spring 70
An actuator 71 that is pressed by the biasing force of is inserted and retractably inserted.

The common terminal 59 and the first and second fixed terminals 60 and 61 are connected to a control circuit 73, a power source 74, and a motor 75 as shown in the wiring diagram of FIG. 7, similar to FIGS. 1 and 2. Ru.

The operation in the above configuration will be explained. Usually the third
As shown in the figure, the operator 53 is in a protruding state, and at this time, the middle part of the movable contact piece 63 is in contact with the fulcrum member 62 connected to the common terminal 59, and the movable contact piece 63 is in contact with the fulcrum member 62 connected to the common terminal 59.
The curved portion of one end 64 of 3 is brought into contact with the common terminal 59. Therefore, the movable contact piece 63 is separated from the first and second fixed terminals 60 and 61, and the switch state is in the OFF state.

From this state, when the operator 53 is pulled in against the biasing force of the return spring 55, the movable contact piece 63 moves between the one end 64 and the wall 6 of the pocket 66 provided on the shaft 54.
8 is brought into contact with the actuator 71.
When the movable contact piece 63 exceeds the fulcrum member 62,
As shown in FIG. 4, it is rotated about a fulcrum member 62. Therefore, the other end 65 of the movable contact piece 63 comes into contact with the first fixed terminal 60, and the switch state is turned on.

In this state, when the operator 53 is further pulled in, the other end 65 of the movable contact piece 63 connects to the first fixed terminal 60.
As shown in FIG. 5, the second fixed terminal 61 is brought into contact with the second fixed terminal 61, and the maximum power is supplied.

In the above state, when the pulling force of the operator 53 is released, the operator 53 is returned to its original position by the return spring 55. Along with this, the movable contact piece 63 sequentially performs the reverse operation to that described above, and returns to the OFF state shown in FIG. 3.

According to the present invention, a large approximately L-shape is formed at one end of the movable contact piece, and the movable contact piece is moved by a pocket provided in the shaft portion, so that the switch device can be made compact, and the movable contact piece can be made smaller. Since the contact surface of the piece to the first and second fixed terminals is a plate surface, a large contact surface can be ensured and temperature rise can be suppressed.

In addition, since the movable contact piece is structured to rotate around the fulcrum member, the coil spring can be strengthened, and the contact pressure of the movable contact piece against the common terminal, first and second fixed terminals can be sufficiently increased. Therefore, the switch device can have excellent vibration resistance.

[Brief explanation of the drawing]

1 and 2 are partially cutaway side views showing an example of a conventional switch device, respectively. FIG. 3 is a partially cutaway side view showing an embodiment of the switch device according to the present invention. 4 and 5 are partially cutaway side views shown to explain the operation of FIG. 2, respectively. 6th
The figure is a perspective view of a movable contact piece according to the present invention. FIG. 7 is an electrical circuit diagram of a switch device according to the present invention. 53 is an operator, 54 is a shaft, 59 is a common terminal, 60 is a first fixed terminal, 61 is a second fixed terminal, 63 is a movable contact piece, and 66 is a pocket.

Claims (1)

[Claims for Utility Model Registration] A switch case, an operator that can be retracted from and retracted from the switch case, and a common terminal, a first fixed terminal, and a second fixed terminal on the inner bottom of the switch case in the operating direction of the operator. The connection state between the fulcrum member provided on the common terminal, the first fixed terminal, and the second fixed terminal is switched by a movable contact piece according to the operating state of the operator, and the controlled device The switch device is capable of changing power supplied to the switch, wherein one end of the movable contact piece is formed into a substantially L-shape and is housed in a pocket of the operating element shaft, and is movable by operating the operating element. An actuator that moves the contact piece in the operation direction of the operator and pushes the movable contact piece downward is provided on the operator shaft part so as to be able to protrude and retract, and a spring housed in the actuator causes the actuator to move in the direction of the operation. The momentary movable contact piece beyond the fulcrum member provided on the common terminal rotates around the fulcrum member, and the first fixed terminal and the plate of the movable contact piece are brought into contact and turned on, and the said pocket is turned on. Rotate one end of the movable contact piece within the
The movable contact piece is moved by bringing one end into contact with the side wall of the pocket as the operator is operated, and the movable contact piece is connected to the first fixed terminal and the second fixed terminal in that order. Switch device.