Safety lock mechanism and automatic machine

Abstract

This safety lock mechanism comprises: a mechanical-lock-type electromagnetic lock switch configured to perform an operation for returning to an original position upon sensing that a lock remains released, the electromagnetic lock switch inserting an operation key fixed to an opening / closing door into a key insertion opening in a switch body fixed to a support-member side, thereby locking the closed opening / closing door by restricting the operation key from falling out; a lock release operation means for operating a lock release means that releases the lock of the operation key within the switch body when not energized; and a stopper member that prevents the full closing of the opening / closing door in conjunction with the lock release operation performed by the lock release operation means.

Description

Safety Lock Mechanism and Automatic Machine

[0001] The present invention relates to a safety lock mechanism and an automatic machine provided with an electromagnetic lock switch on an opening / closing door.

[0002] In an automatic machine such as a machine tool, a safety lock mechanism equipped with, for example, an electromagnetic lock switch is provided so that the internal device does not drive when the opening / closing door is open. Patent Document 1 below discloses a technology related to an electromagnetic lock switch. The electromagnetic lock switch is configured such that the detection switch portion of the key switch body is actuated by an operation key. The key switch body is fixed to a safety fence on the support member side, and the operation key is fixed to an opening / closing door that opens and closes the entrance / exit. When the opening / closing door closes the entrance / exit of the safety fence, the operation key attached to the opening / closing door is inserted into the key insertion hole of the key switch body. At this time, the movable part of the solenoid advances by the biasing force of the spring member, the movable plunger is lifted via a lever, and the operation key is locked to the key switch body, restricting the opening and closing of the opening / closing door.

[0003] On the other hand, to release the lock on the operation key, the electromagnetic lock switch is released by turning on the power of the automatic machine, causing the solenoid to be energized and moving the movable plunger against the return spring. Also, a mechanical lock type electromagnetic lock switch can be unlocked by operating the key cylinder, which is the unlocking means, with a release key even in a non-energized state where the power of the automatic machine is turned off. Therefore, for example, in the case of a machine tool, the front opening / closing door can be opened by unlocking, and an operator can perform operations such as tool replacement and maintenance in the processing chamber inside the machine.

[0004] Japanese Patent Application Laid-Open No. 2001-132291

[0005] However, with mechanical lock-type electromagnetic lock switches, operators sometimes forget to reset the lock after use, even though it's necessary to do so. If the machine is powered on while the lock is still released, an error will occur, but it can be difficult to determine what the error is if the operator doesn't realize they forgot to reset the lock. Safety lock mechanisms in automated machines are required by international and user standards to have a configuration where the release part, such as an electromagnetic lock switch, is not easily accessible to the operator. As a result, mechanical lock types like electromagnetic lock switches have poor operability when unlocked using a release key. Furthermore, the configuration of a safety lock mechanism that is difficult to access increases the likelihood that the operator will forget to reset the lock to its original position, as mentioned above.

[0006] Therefore, the present invention aims to provide a safety lock mechanism and an automated machine in order to solve these problems.

[0007] A safety lock mechanism in one aspect of the present invention includes a mechanical lock type electromagnetic lock switch that locks the closed opening / closing door by inserting an operating key fixed to the opening / closing door into a key insertion slot of a switch body fixed to a support member, thereby restricting the removal of the operating key; a lock release operation means for operating a lock release means for releasing the lock of the operating key inside the switch body when no power is supplied; and a stopper member that prevents the opening / closing door from closing completely in conjunction with the lock release operation of the lock release operation means.

[0008] Another embodiment of the present invention provides an automatic machine in which a device controllable by a control device is mounted inside an opening / closing door, and a safety lock mechanism is attached to the opening / closing door, the safety lock mechanism comprising: a mechanical lock type electromagnetic lock switch that locks the closed opening / closing door by restricting the removal of an operating key fixed to the opening / closing door when the operating key is inserted into a key insertion slot of a switch body fixed to a support member that supports the opening / closing door so that it can be opened and closed; a lock release operation means for operating a lock release means for releasing the lock of the operating key inside the switch body when it is not energized; and a stopper member that prevents the opening / closing door from being fully closed in conjunction with the lock release operation of the lock release operation means.

[0009] According to the above configuration, for example, if a safety lock mechanism is provided on the opening and closing door of the automatic machine, the door is locked when an operating key is inserted into the key slot of the switch body. On the other hand, with a mechanical lock type electromagnetic lock switch, even if the automatic machine is powered off and the door is locked, the door can be opened by operating the unlocking means, which unlocks the operating key, and the door is prevented from being fully closed by a stopper. Therefore, an operator who wants to close the door and turn on the automatic machine after working inside the machine will notice that the lock is still released and will operate the unlocking means back to its original position.

[0010] This is a front view of a machine tool with a safety lock mechanism. This is a block diagram showing the control system of a machine tool with a safety lock mechanism. This is a perspective view showing the safety lock mechanism. This is a perspective view showing the safety lock mechanism. This is a perspective view showing the safety lock mechanism.

[0011] An embodiment of the safety lock mechanism and automatic machine according to the present invention will be described below with reference to the drawings. In this embodiment, a machine tool equipped with a safety lock mechanism on the opening and closing door on the front of the machine will be used as an example. Figure 1 is a front view of the machine tool with the safety lock mechanism. Figure 2 is a block diagram showing its control system. In this embodiment, although the specific internal configuration of the machine tool 1 is not shown, a pair of spindle units 3 and 4 face each other on the left and right sides of the machine when viewed from the front, and each is equipped with a turret unit 5 or a turret unit 6, making it a two-spindle opposing lathe.

[0012] Inside the machine, which is covered by the machine body cover 10, is a sealed machining chamber, and on the front of the cover, there are sliding doors 11 and 12 on both the left and right sides of the central section 13. The machine tool has a first machining chamber consisting of a spindle unit 3 and a turret unit 5 inside the door 11, and a second machining chamber consisting of a spindle unit 4 and a turret unit 6 inside the door 12. An operation display device 7 is mounted in the central section 13 located between the doors 11 and 12. This operation display device 7 functions as an input interface for operating each device and as an input interface for receiving machining programs, etc.

[0013] The machine tool 1 is equipped with a control device 8 for automatically controlling drive devices such as spindle units 3 and 4, turret units 5 and 6, and other drive units. The control device 8 consists of a microprocessor (CPU) 31, ROM 32, RAM 33, and non-volatile memory 34, all connected via a bus line. The CPU 31 provides overall control of the control device, the ROM 32 stores system programs and control parameters executed by the CPU 31, and the RAM 33 stores temporary calculation data and display data.

[0014] Furthermore, the non-volatile memory 34 stores information necessary for processing performed by the CPU 31, including the sequence program for the machine tool 1. The control device 8 is provided with I / O ports 35, through which the drive motors of the spindle units 3 and 4, the turret units 5 and 6, and the automatic workpiece transfer machine 2 are connected via drivers. In addition, the operation display device 7, located on the front of the machine, is also connected to the control device 8 via the I / O ports 35.

[0015] These machine tools 1 perform automated machining according to a machining program tailored to the workpiece. The workpiece is held by the spindle chucks of the spindle units 3 and 4, and rotation is applied to the workpiece according to the output of the spindle motor. In the turret units 5 and 6, multiple tools are detachably mounted on polygonal tool posts via tool holders, and the appropriate tool is selected by swivel indexing according to the machining content. Furthermore, as the tool post moves in each axial direction within the machining chamber, predetermined machining, such as outer diameter cutting, is performed by applying the cutting edge of the tool to the rotating workpiece.

[0016] In machine tool 1, a changeover is required due to changes in the workpiece or the machining process applied to the workpiece. This involves changing the spindle chuck in the spindle units 3 and 4, and changing the tool on the tool post. For safety reasons, the power to machine tool 1 is turned off during work inside the machine, and the movable parts such as the drive motors are stopped. In addition, the safety lock mechanism provided on the opening and closing doors 11 and 12 is activated, and the doors 11 and 12 are locked when closed. However, since this would prevent the changeover from being performed, the electromagnetic lock switch 20, which is part of the safety lock mechanism, is designed to release the lock.

[0017] In other words, even if the electromagnetic lock switch 20 is locked in an unpowered state with the power off, it is a mechanical lock type, so the operator can release it by using the release key. On the other hand, if the electromagnetic lock switch 20 could be easily released, sufficient safety could not be ensured during the operation of the machine tool 1. Therefore, in this embodiment, the electromagnetic lock switch 20 is positioned higher than the opening and closing doors 11 and 12 and is covered by the upper surface cover 15 so that the operator cannot easily access it.

[0018] As shown by the dashed line in Figure 1, the electromagnetic lock switch 20 consists of a switch body 21 fixed to the main body of the machine above the opening and closing doors 11 and 12, and an operation key 22 fixed to the opening and closing doors 11 and 12, which open and close in the left and right directions. As will be described in more detail later, the operation key 22 is inserted into a key insertion slot formed in the switch body 21, and the opening and closing operation of the opening and closing doors 11 and 12 is restricted by the electromagnetic lock switch 20 in a locking state. To allow the electromagnetic lock switch 20 to be released, two release operation windows 16 are provided in the upper surface cover 15 at positions corresponding to each switch body 21.

[0019] Figures 3 to 6 are perspective views showing the safety lock mechanism. While these figures show the mechanism located on the opening / closing door 11 side, the mechanism on the opening / closing door 12 side has the same structure and is arranged symmetrically. Furthermore, Figures 3 and 4 are views from the front of the aircraft, similar to Figure 1, while Figures 5 and 6 are views from the opposite side, inside the aircraft. Additionally, Figures 3 and 5 show the locked state, while Figures 4 and 6 show the unlocked state relative to the mechanical lock.

[0020] The electromagnetic lock switch 20 is integrated with the switch body 21 by fixing the switch bracket 23 to it, and is fixed to a beam member (support member) of a machine tool 1 (not shown) via the switch bracket 23. On the other hand, a rod 41 extends upward from the opening / closing door 11, and an operating key 22 is attached to its tip so as to protrude toward the switch body 21. The operating key 22 is fixed via a key bracket 17 so as to be oriented horizontally, which is the opening and closing direction of the opening / closing door 11. Therefore, when the opening / closing door 11 is closed, the operating key 22 is inserted into the key insertion slot 211 of the switch body 21.

[0021] The electromagnetic lock switch 20 locks within the switch body 21 into which the operating key 22 is inserted. When the solenoid inside the switch body 21 is energized, the plunger moves against the return spring, releasing the lock and allowing the operating key 22 to move freely. When the power to the machine tool 1 is turned off while the opening / closing door 11 is closed, the power to the solenoid is cut off, and the plunger remains biased by the return spring, maintaining the locked state. Consequently, the opening and closing operation of the opening / closing door 11 is restricted, making it difficult to easily enter the machine.

[0022] Incidentally, the power to the machine tool 1 is turned off to ensure safe operation inside the machine, but to enable operation inside the machine, the electromagnetic lock switch 20 is provided with a release mechanism that allows manual unlocking. The electromagnetic lock switch 20 is configured such that, similar to the one described in Patent Document 1, for example, the lock when the power is not supplied can be released by rotating the key cylinder, which is the lock release means inside the switch body 21, with a release key. In this embodiment, a lock release operation means 25 for forcibly releasing the lock is provided on the switch bracket 23 which is integrated with the switch body 21.

[0023] The unlocking operation means 25 consists of a cylindrical guide 251 fixed perpendicularly to the switch bracket 23, into which a rotating shaft 252 connected to the key cylinder in the switch body 21 is slidably inserted. A hexagonal hole 501, which serves as a keyhole, is formed on the end face of the rotating shaft 252, and a hexagonal screwdriver 38 (only the tip portion is shown) acts as a release key, allowing the shaft to rotate around its central axis within the guide 251. An arc-shaped notch 502 is also formed in the middle portion of the guide 251 when viewed in the axial direction, and an operating pin 253 fixed to the rotating shaft 252 protrudes radially from it. The unlocking operation means 25 is located in a position corresponding to the unlocking operation window 16 shown by the dashed line, and can be operated by inserting the hexagonal screwdriver 38 from the outside of the upper surface cover 15.

[0024] The unlocking operation means 25 is configured to swing the operating pin 253 when the key cylinder inside the switch body 21 is rotated, and a stopper member 26 associated with this operating pin 253 is assembled to the switch bracket 23. The stopper member 26 is an L-shaped lever member and is pivotally supported on the switch bracket 23 by a support pin 261. The L-shaped portion 263 at the tip of the stopper member 26 is located outside the switch bracket 23 and is longer and heavier than the opposite side of the support pin 261. Therefore, as shown in Figure 3, the stopper member 26 is configured to be displaced between a retracted position in which the L-shaped portion 263 is lifted by the operating pin 253 applied from above, and a stopped position in which the L-shaped portion 263 falls downward due to its own weight when the operating pin 253 is released, as shown in Figure 4.

[0025] With the support of the operating pin 253 released, the stopper member 26 is pressed against the receiving portion 231 formed on the switch bracket 23 from above, maintaining a nearly horizontal stopping position. As shown in Figure 3, the normal state of the stopper member 26 with the operating pin 253 pressed against it is when the stopper member 26 is retracted, and at this time the L-shaped portion 263 of the stopper member 26 is lifted and floating away from the receiving portion 231. Then, when a clockwise rotation is applied to the rotation axis 252 by the hexagonal screwdriver 38 to release the lock, as shown in Figure 4, the operating pin 253 swings in the same direction and moves away from the stopper member 26.

[0026] As shown in Figures 4 and 6, the stopper member 26, which is pivotable and supported by the receiving portion 231, is configured to strike the block 42 fixed to the rod 41. In other words, the stopper member 26 is designed to prevent the opening / closing door 11 from closing completely once it has been opened by colliding with the block 42 when it is in a stopped position. On the other hand, in order to move the opening / closing door 11 to the fully closed position, the rotation shaft 252 is rotated counterclockwise with the hexagonal screwdriver 38, and the stopper member 26 is returned to the retracted position shown in Figure 3 with the action pin 253.

[0027] Furthermore, when the opening / closing door 11 is closed, the operating key 22 is inserted into the key insertion slot 211 of the switch body 21, causing the electromagnetic lock switch 20 to send a detection signal to the control device 8, allowing confirmation that the opening / closing door 11 is fully closed. Therefore, if the stopper member 26 collides with the block 42, no detection signal is sent to the control device 8, and it is determined that the opening / closing door 11 is open.

[0028] Next, when performing changeover work or maintenance on the machine tool 1, the power is turned off with the opening / closing door 11 closed. At this time, the electromagnetic lock switch 20 is locked when the operating key 22 is inserted into the key insertion slot 211 of the switch body 21, and the solenoid does not act when the power is turned off, preventing the operating key 22 from being removed. Furthermore, as shown in Figures 3 and 5, the lock release operation means 25 has an operating pin 253 that lifts the L-shaped portion 263 of the stopper member 26, thus avoiding a collision between the stopper member 26 and the block 42.

[0029] Next, in order to open the opening / closing door 11 and perform work, the lock is released by rotating the key cylinder of the electromagnetic lock switch 20. To do this, the worker inserts a hex screwdriver 38 through the release operation window 16 located at a high position and rotates the rotation shaft 252 of the lock release operation means 25 located inside the upper surface cover 15 as shown in Figure 4. This rotation releases the lock of the electromagnetic lock switch 20, and the stopper member 26, which is no longer supported by the operating pin 253, swings under its own weight, and the L-shaped portion 263 rests on the block 42. Then, when the opening / closing door 11 is opened, the stopper member 26 that has fallen from the block 42 hits the receiving portion 231 of the switch bracket 23 and comes to a nearly horizontal stopping position.

[0030] Subsequently, when the worker finishes their work in the processing room and closes the opening / closing door 11, the block 42 will hit the stopper member 26, preventing it from closing completely, and the worker will realize that the stopper member 26 is in action. In the safety lock mechanism of this embodiment, if the lock is released and the opening / closing door 11 is opened, the lock release operation means 25 must be returned to its original state before closing it. Therefore, before closing the opening / closing door 11 after finishing work, the worker inserts a hexagonal screwdriver 38 through the release operation window 16 and rotates the rotating shaft 252 in the opposite direction, thereby returning the electromagnetic lock switch 20 to its original state.

[0031] However, some operators may not return the unlocking mechanism 25 to its original position, nor may they notice that the opening / closing door 11 is not completely closed. In this state, the operation key 22 is not inserted into the key slot 211 of the switch body 21, and the open state of the opening / closing door 11 is confirmed by the absence of a detection signal. In this embodiment, if the power is turned on without the control device 8 receiving a detection signal, the operation display device 7 acts as an alarm device, and the open state of the opening / closing door 11 is indicated on the monitor of the operation display device 7 by displaying a message indicating that the key cylinder has not been returned and by providing an audible alert.

[0032] Therefore, according to the safety lock mechanism and machine tool 1 of this embodiment, the electromagnetic lock switch 20 is covered by the upper surface cover 15 and cannot be seen directly from the outside, and is located higher than the opening and closing doors 11 and 12, so it is not easily accessible to the operator as required by international standards. However, the lock can be released by inserting a hexagonal screwdriver 38 through the release operation window 16 of the upper surface cover 15, so the handling of the electromagnetic lock switch 20 is not inconvenient.

[0033] Furthermore, with conventional mechanical lock-type electromagnetic lock switches, the difference between the normal state and the unlocked state is not easily discernible from the outside, making it easy to forget to return the key cylinder. However, in this embodiment, although the electromagnetic lock switch 20 is not directly visible, the stopper member 26 prevents the opening and closing doors 11 and 12 from closing completely, making it possible to notice if the lock has been forgotten to be returned. Moreover, even if the operator still does not notice that the lock has been forgotten to be returned, the monitor display on the operation display device 7 can be used to reliably alert the operator to the fact that the lock has been forgotten to be returned.

[0034] Although one embodiment of the present invention has been described, the present invention is not limited thereto, and various modifications are possible without departing from its spirit. For example, although a machine tool was used as an example in the above embodiment, other automatic machines may be used as long as they are equipped with a safety lock mechanism on the opening and closing door. Also, although the keyhole of the lock release operation means 25 is hexagonal in the above embodiment, it may be a flathead shape corresponding to a flathead screwdriver.

[0035] 1... Machine tool 3,4... Spindle unit 5,6... Turret unit 7... Operation display device 8... Control device 11,12... Opening / closing door 15... Upper surface cover 16... Release operation window 20... Electromagnetic lock switch 21... Switch body 22... Operation key 23... Switch bracket 25... Lock release operation means 26... Stopper member 38... Hex screwdriver 41... Rod 42... Block 251... Guide 252... Rotating shaft 253... Actuating pin

Claims

1. A safety lock mechanism comprising: a mechanical lock type electromagnetic lock switch that locks the closed opening / closing door by inserting an operating key fixed to the opening / closing door into a key insertion slot of the switch body fixed to the support member side, thereby restricting the removal of the operating key; a lock release operation means for operating a lock release means for releasing the lock of the operating key inside the switch body when it is not energized; and a stopper member that prevents the opening / closing door from closing completely in conjunction with the lock release operation of the lock release operation means.

2. The safety lock mechanism according to claim 1, wherein the unlocking operation means has an operating pin fixed to a rotating shaft that rotates the unlocking means within the switch body, and the stopper member is capable of swinging between a stopping position that prevents the opening / closing door from moving to a fully closed position and a retracted position that enables the opening / closing door to be fully closed, and the position between the stopping position and the retracted position is operated by the operating pin.

3. The safety lock mechanism according to claim 2, wherein the rotating shaft of the unlocking operation means has a keyhole formed on its end face corresponding to the shape of a screwdriver, and the entire mechanism is covered by a cover having an unlocking operation window through which the screwdriver passes.

4. The safety lock mechanism according to claim 3, wherein the opening and closing door is a sliding door, the operating key is attached to a rod fixed so as to protrude upward, the switch body is fixed to the upper part of the opening and closing door, and the rod and the switch body at the upper part of the opening and closing door are covered by an upper surface cover in which the release operation window is formed.

5. An automatic machine having a device that can be driven and controlled by a control device installed inside an opening / closing door, and a safety lock mechanism attached to the opening / closing door, wherein the safety lock mechanism comprises: a mechanical lock type electromagnetic lock switch that locks the closed opening / closing door by restricting the removal of an operating key fixed to the opening / closing door when the operating key is inserted into a key insertion slot of a switch body fixed to a support member that supports the opening / closing door so that it can be opened and closed; a lock release operation means for operating a lock release means for releasing the lock of the operating key inside the switch body when it is not energized; and a stopper member that prevents the opening / closing door from being fully closed in conjunction with the lock release operation of the lock release operation means.

6. The automatic machine according to claim 5, wherein the electromagnetic lock switch transmits a detection signal to the control device when the operating key is inserted into the key slot of the switch body, and the control device notifies the connected alarm device of the failure to return the lock release means based on the detection signal.

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