JP2001297807A - Safety interlock structure of electric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety interlock structure that has a function of protecting operators and others from a dangerous voltage existing in the electric apparatus and a function of preventing pulling-out of a bayonet plug. SOLUTION: The safety interlock structure (26) comprises a sliding movable protection plate (30) which is provided at the box (10) of an electric apparatus. The movable protection plate (30) comprises a terminal protector portion (44) to cover an electric terminal (20), a plug stopper portion (44) to prevent pulling- out of a bayonet plug (14) by engaging with the shoulder of the bayonet plug (14), and a movement stopper portion (56) to interfere with an operating button (24) of the power source main switch (18). Unless the power source main source switch (18) is moved to 'off' position and the electric connection with the electric apparatus is stopped, the access to the electric terminal (20) cannot be made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety interlock structure for protecting an operator or other persons from dangerous voltage present in a communication device or other electric device. Here, the “dangerous voltage” means UL (Underwriters Laborator)
ies Inc.) means a voltage value (DC60V and AC42.4V or more) at which there is a risk of electric shock specified in the standard. In addition, "safety interlock" is a means to prevent a person from accessing a dangerous part unless the dangerous state is removed, or automatically removes the dangerous state when accessing. Means means.

[0002]

2. Description of the Related Art Japanese Patent Laying-Open No. 3-257773 discloses a plug for preventing a plug inserted from the outside of a casing into a plug receptacle provided in a casing of an electronic device from coming out of the plug receptacle. A plug retaining structure is described. This structure is intended only to prevent the insertion plug from coming off, and does not include a safety interlock structure in consideration of the safety of the operator and a third party, so that an accident such as electric shock or short circuit is induced. There is a possibility and there is room for improvement. Further, in this retaining structure, since an L-shaped fixture is fixed to the bottom surface of the housing with screws and a system stopper is used to prevent the insertion plug from coming off, a plurality of mechanical parts are required, and component costs are reduced. In addition, this is one of the factors that increase the processing cost.

Japanese Patent Laying-Open No. 3-257773 discloses a structure in which a retaining cover is attached to a housing of an electronic device so as to be openable and closable using a hinge to prevent the insertion plug from coming off. When the plug is pulled out of the outlet, the retaining cover comes into close contact with the housing by the action of the spring to cover the opening of the outlet, thereby protecting the terminals of the outlet.
However, the retaining cover can protect only the terminal of the outlet, and cannot prevent access to other dangerous voltages existing in the housing of the electronic device.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a safety interlock structure capable of protecting an operator or other persons from a dangerous voltage existing in a communication device or other electric device. is there. Another object of the present invention is to provide a safety interlock structure which is simple in structure and can be realized with a minimum number of parts. Another object of the present invention is to provide a safety interlock structure that can be easily attached to a housing and is easy to operate. Another object of the present invention is to provide a safety interlock structure having a function of preventing the insertion plug from coming off.

[0005]

SUMMARY OF THE INVENTION The present invention provides a safety interlock structure in an electric device having an exposed electric terminal and a power supply main switch in an apparatus housing. A power supply main switch is disposed adjacent to each other in a housing, and a movable protection plate (shutter) for covering the terminals is provided between a first position for covering the terminals and a second position for allowing access to the terminals. It is movably mounted on the housing, and the movable protection plate is provided with the operation member (swing button or push button) of the power supply main switch from the first position when the power supply main switch is in the “off” state. Although the movable protection plate is allowed to move to the second position, a movement inhibiting member is provided to prevent the movement of the movable protection plate from the first position to the second position when the power supply main switch is in the "ON" state. It is characterized in that the.

As described above, when the movable protective plate is in the first position, the movable protective plate covers the electrical terminals, so that the terminals are exposed and the terminals can be accessed only when the movable protective plate is in the second position. Only when it is in. Since the movable protection plate is provided with a movement inhibiting member that cooperates with the operation member of the power supply main switch, the power supply main switch must be turned off in advance to move the movable protection plate to the second position. There must be. Therefore, whenever the terminal is exposed by bringing the movable protection plate to the second position, the power supply main switch is always "OFF", and the power supply to the electric terminal is stopped. As described above, since the access to the electric terminal is enabled only when the power supply to the electric terminal is stopped, it is possible to reliably protect a person from harm caused by the dangerous voltage.

[0007] The movable protective plate that achieves such a safety interlock function can be formed as a single component, so that it is easy and easy to mount and operate, thereby improving productivity and reducing costs.

In a preferred embodiment, the movable protection plate is of a swing type, and is pivotally attached to the housing so as to be swingable between the first position and the second position using a threaded pin or the like. According to this configuration, the movable protection plate can be easily mounted on the housing.

In another embodiment, the movable protection plate is of a sliding type, and is mounted on the housing so as to be slidable between the first position and the second position.

In a preferred embodiment, in the first position, the movable protection plate is fixed to the housing by fixing screws. In this case, the movable protection plate does not deviate from the first position due to vibration of the housing or unexpected external force.

In a further preferred embodiment, the movable protection plate is provided with a plug restraining portion (retaining portion) for locking the insertion plug when the protection plate is at the first position. A plug receiver into which a plug of a power cord for supplying electric power to the electric device is inserted is provided on a housing of the electric device adjacent to the electric terminal. According to this structure, when the movable protection plate is brought to the first position, the plug suppressing portion is engaged with the insertion plug, and the insertion plug inserted into the plug receiver is prevented from coming off from the plug receiver. To prevent.
Therefore, by operating the single movable protection plate, the safety interlock and the function of preventing the insertion plug from coming off are simultaneously achieved. The above-described features and effects of the present invention, as well as other features and effects, will be further clarified as described in the following examples.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. Referring to FIGS. 1 and 2, a plug 10 of a power cord 12 for supplying power to an internal power supply (not shown) of the electric device is inserted into the housing 10 of the electric device in a predetermined positional relationship. A plug receiver 16 for plugging in the power supply, a power supply main switch 18 for controlling power supply to the power supply device, and a terminal block 22 having a plurality of electric terminals 20 are mounted. In the illustrated embodiment, the power supply main switch 18 has a swing type operation button 24, but the operation button may be a push button type that enters and exits the housing.

Referring to FIG. 1 and FIG. 3, the safety interlock structure 26 of the present invention includes
There is provided a movable protection plate 30 pivotally mounted to be able to swing to zero. The screw 28 is screwed into the screw hole 34 of the housing 10 through the screw insertion hole 32 of the movable protection plate 30, and the movable protection plate 30 swings clockwise and counterclockwise around the axis 36 of the screw 28. can do.

In order to regulate the swing angle of the movable protection plate 30, bent rotation restriction portions 38 are formed at both ends of the movable protection plate 30, and these rotation restriction portions 38
It is engaged with a pair of left and right rotation inhibiting slots 40 formed at zero. The movable protection plate 30 can be swung between the first position shown in FIG. 1 and the second position shown in FIG. The plug receiver 16 and the electric terminal 20 are connected to the movable protection plate 30.
1 is located in the first position shown in FIG. 1, the electric terminals 20 are covered by the movable protection plate 30, and the plugs 14 are arranged in an appropriate positional relationship so as to be restrained by the movable protection plate 30. .

The movable protection plate 30 is provided with a dangerous voltage (the electric terminal 2).
In consideration of the spatial distance and creepage distance from 0), a highly insulating material, more preferably a material having a high flame retardancy,
It can be formed of an L certified material, for example, can be formed of ABS (acrylonitrile butadiene styrene) resin or the like.

As shown in FIGS. 1 and 3, the movable protection plate 30 has a simple shape made of a bent strip. When the movable protection plate 30 is at the first position, the movable protection plate 30 is detached from the terminal protection portion (or shutter) 42 located immediately above the terminal block 22 and the insertion plug 14 inserted into the plug receiver 16. Plug suppressor 44 for preventing
Having. The plug restraining portion 44 has a plug restraining surface 46 that engages with the shoulder portion 48 of the insertion plug 14 from the insertion and removal direction. When the plug suppressing surface 46 is engaged with the shoulder portion 48 of the insertion plug 14, the plug suppressing portion 44
A notch 47 is formed to prevent the power cord 12 from interfering with the power cord 12.

A screw hole 50 (see FIG. 3) is provided in the rotation restricting portion 38 on the right side of the movable protection plate 30.
0 has a hole 54 for passing the fixing screw 52 on the right side of the rotation suppression slot 40 on the right side. The movable protection plate 30 is screwed into the screw hole 50 through the hole 54 to thereby fix the movable protection plate 30. It can be fixed at the first position shown in FIG.

Referring to FIG. 5, power supply main switch 1
When the operation button 24 of FIG. 8 is pushed down to the “ON” or “OFF” side, the button swings as shown in FIGS. 5 (F) and 5 (E). The movable protection plate 30 is provided with a movement inhibiting member (stopper) 56 having an L-shaped cross section for suppressing rotation of the movable protection plate 30 by interfering with the operation button 24. As shown in FIG. 5, the positional relationship between the power supply main switch 18 and the movement suppressing member 56 is determined when the operation button 24 is pushed down to the “ON” side (FIG. 5F).
The movement suppressing member 56 is set so as to interfere with the side rising surface 58 on the “OFF” side of the operation button 24.

Next, the operation of the safety interlock structure 26 will be described. By pressing down the operation button 24 of the power supply main switch 18 to the “OFF” side, the movable protection plate 3
The interference between the zero movement suppression member 56 and the side surface of the operation button 24 is eliminated, and the protection plate 30 can be rotated counterclockwise around the rotation axis 36 to the position shown in FIG. Since the rotation restricting portion 38 of the movable protection plate 30 is engaged with the rotation suppressing slot 40, the swing angle of the movable protection plate 30 is restricted. In this state, necessary wiring can be connected to the electric terminals 20 of the housing, and the plug 14 of the power cord can be inserted into and removed from the plug receiver 16 of the housing 10.

After the insertion plug 14 is inserted, the movable protection plate 30 is rotated clockwise to bring it to the position shown in FIG. The detent surface 46 engages the shoulder 48 of the plug 14 from behind, holding down the shoulder 48. As a result, the insertion plug 14 is prevented from coming off against an external force acting on the power cord 12. At the same time, the terminal protection portion 42 of the movable protection plate 30
Are brought directly above the terminal block 22 and cover the electric terminal 20, so that the operator and a third party cannot access the dangerous voltage applied to the terminal 20. Thus, just by rotating the movable protection plate 30 clockwise,
Safety interlock against dangerous voltage and plug 14
Is simultaneously achieved.

In this state, when the fixing screw 52 is screwed into the screw hole 50 through the hole 54 and the movable protection plate 30 is fixed to the housing 10, vibration of the housing and unexpected external force act on the movable protection plate 30. Also, the movable protection plate 30 does not rotate.

Operation button 24 of power supply main switch 18
Is pushed down to the “ON” side, power is supplied to the power supply circuit of the electric device. As described above, since the movable protection plate 30 covers and hides the electric terminals 20, the electric terminals 20 to which the voltage is applied cannot be accessed. During energization of the electric device, the operation button 24 of the power supply main switch 18 is set to “O”.
5B, and the movement suppressing member 56 of the movable protection plate 30 interferes with the side rising surface 58 of the operation button 24 as shown in FIG.
Cannot be turned counterclockwise.

Operation button 24 of power supply main switch 18
Only by pushing down to the “OFF” side, the movable protection plate 30 is rotated counterclockwise, and the insertion and removal of the insertion plug 14 and the access to the electric terminal 20 can be performed. At this time, the dangerous voltage to the electric terminal 20 has already been released by turning off the power supply main switch 18 in advance.
There is no danger to the operator and third parties.

Next, a second embodiment of the safety interlock structure of the present invention will be described with reference to FIG. In the above-described first embodiment, the movable protection plate 30 is configured as a swing type, but in the second embodiment, the movable protection plate 30 is configured as a sliding type. In FIG. 6, components common to those of the first embodiment described above are denoted by the same reference numerals, and duplicate description will be omitted. Only the differences will be described with reference to FIG. 6. The movable protective plate 30 is provided at each end with a sliding elongated hole 60 constituting a sliding mechanism, and the elongated hole 60 is provided with a protective plate fixed to the housing 10. The movable restraint screw 62 is engaged. The sliding protection plate 30 can be moved in the direction of the arrow in the drawing with these screws 62 loosened. The plug receiver 16, the terminal block 22, and the power supply main switch 18 are arranged in an appropriate positional relationship to exhibit the safety interlock effect and the plug retaining effect of the present invention.
Are located in

In the position shown in FIG. 6A, the protective plate 30 covers and hides the electric terminals 20 and at the same time prevents the insertion plug 14 from coming off. In the position shown in FIG.
Access and insertion / removal of the insertion plug 14 become possible.

[0026]

According to the safety interlock structure of the present invention, the movable protection plate cannot be moved to the second position unless the power supply main switch is turned off. Only when it is stopped can access the electrical terminals. Therefore, it is possible to reliably protect a person from harm caused by the dangerous voltage.

Further, since the safety interlock function can be achieved by the movable protection plate which is a single component having a simple structure, the mounting and operation are easy and simple, and the productivity and cost can be improved. it can.

In the embodiment in which the plug suppressing portion for locking the insertion plug is provided on the movable protection plate, the safety interlock function and the stopper of the insertion plug can be simultaneously and easily realized by one-touch operation. it can.

[Brief description of the drawings]

1 (A) is an elevation view of a first embodiment of a safety interlock structure of the present invention, and FIG. 1 (B) is a sectional view taken on line B-B of FIG. 1 (A);
It is sectional drawing which followed the B line.

FIG. 2 shows a state where a movable protection plate of FIG. 1 is removed.

FIG. 3 shows the movable protection plate shown in FIG. 1 (A).
Is an elevation view and (B) is a side view.

FIG. 4 shows a state where the movable protection plate shown in FIG. 1 is swung.

5A is an elevation view showing a relationship between a power supply main switch and a movement suppressing member, FIG. 5B is a side view of FIG. 5A viewed from an arrow B, and FIGS. 5C and 5D show operation buttons. "OFF" respectively
And an elevation view showing the position pushed down to the “ON” side,
(E) and (F) are side views showing the state where the operation button was pushed down to the “OFF” and “ON” sides, respectively.

6 (A) and 6 (B) are elevation views showing a movable interlocking plate at first and second positions, respectively, showing a second embodiment of the safety interlock structure of the present invention. C)
Is a side view.

[Explanation of symbols]

 10: Housing of electric device 12: Power cord 14: Plug-in plug 16: Plug receptacle 18: Power main switch 20: Electric terminal 24: Operating member of power main switch 26: Safety interlock structure 28: Axis (screw) 30: Movable protection plate 38/40, 60/62: movement restricting means 42: terminal protection part 44: plug suppression part 52: fixing screw 56: movement suppression member

Continued on front page F-term (reference) 4E360 AB04 AB12 AB22 BA04 BB20 BC03 BC05 EA13 EA18 ED02 ED03 ED16 ED27 FA08 GA44 GB93 GB94 GC08 5E021 FA03 FA14 FB07 FB14 FB21 FC36 HC11 HC31 5E086 DD05 JJ17 LL02 LL18

Claims (6)

[Claims] 1. An electric device having an exposed electrical terminal and a power supply main switch in a device housing: the terminal and the power supply main switch are arranged adjacent to each other in the housing, and movable protection for covering the terminal is provided. A plate is mounted on the housing so as to be movable between a first position covering the terminal and a second position allowing access to the terminal, and the movable protection plate cooperates with an operating member of the power supply main switch. Works to allow the movable protection plate to move from the first position to the second position when the power supply main switch is in the “OFF” state,
A safety interlock structure for an electric device, further comprising a movement suppressing member for preventing movement of the movable protection plate from the first position to the second position when the power supply main switch is in an "ON" state. 2. The safety interlock structure according to claim 1, wherein the movable protection plate is pivotally attached to a housing so as to swing between the first position and the second position. 3. The safety interlock structure according to claim 1, wherein the movable protection plate is slidably mounted on the housing between the first position and the second position. 4. The safety interlock structure according to claim 1, further comprising a fixing screw for fixing the movable protection plate to the housing at the first position. 5. The safety interlock structure according to claim 1, further comprising means for restricting movement of the movable protection plate between the first position and the second position. 6. A plug receiver into which a plug of a power cord is inserted is provided in a housing of the electric device adjacent to the terminal, and the movable protection plate is provided with the first protection plate.
When the movable protection plate is located at the first position, the plug plug inserted into the plug receiver is prevented from falling out of the plug receiver when the movable protection plate is located at the first position. A safety interlock structure according to any one of claims 1 to 5, wherein the safety interlock structure is adapted to: