machine tool

Abstract

Machine tool (1), comprising: a door (3) designed to separate a processing area (2) and an exterior of the machine and to be openable / closable; a mechanism (7) for detecting the closed state of the door (3), which detects that the door (3) is in a predetermined closed position; a door locking mechanism (8, 13) that locks or unlocks the door (3); and a locking mechanism (5a) that permits operation when the door (3) is in a predetermined closed position and is in a locked state, and allows the door lock mechanism (8, 13) to bring the door (3) into an unlocked state in a state in which an unlocking condition of the door (3) is detected and when a key element (9, 12) is removed from a predetermined position, and, after the door (3) is unlocked, allows the door lock mechanism (8, 13) to bring the door (3) into the locked state only when the key element (9, 12) is inserted into the predetermined position in a state in which the mechanism (7) for detecting the closed state of the door (3) detects that the door (3) is in the predetermined closed position, wherein the key element (9, 12) constitutes an obstacle that is designed to preventthat the door (3) is brought into the specified closed position when the key element (9, 12) is in the specified position when the door (3) is open.

Description

Background of the invention 1. Field of the invention

[0001] The present invention relates to a machine tool comprising a locking mechanism which allows a machining operation when a door is arranged in a closed position and is in a locked state. 2. Description of the state of the art

[0002] A locking mechanism is arranged on a large machine tool to prevent a third person from accidentally activating a process operation while a worker is working in the machine tool.

[0003] Conventional locking mechanisms of this type include, for example, the one described in Japanese patent application publication no. Hei 5-123937. According to the prior art, the locking mechanism is configured such that a switch is closed, which in turn switches a power supply circuit, such as a spindle motor or the like, when it is detected that the door is open. Further related prior art is disclosed in DE 10 2007 008 701 A1, DE 693 20 840 T3, DE 20 2005 009 513 U1 and EP 1 134 765 A1. Summary of the invention

[0004] However, the conventional locking mechanism has a problem, and the problem is that even if the worker is working inside the machine tool, a third person can bring the door into a closed state by moving the door into a closed position.

[0005] The present invention was made taking into account the above facts according to the prior art, and it is an object of the present invention to create a machine tool which makes it possible to prevent a machining operation from being started, even if a third person mistakenly puts a door into a closed state, and it is easy for the third person to recognize that they have mistakenly put the door into a closed state.

[0006] The above-mentioned problem is solved by a machine tool according to claim 1. Preferred embodiments are the subject of the dependent claims.

[0007] According to the present invention, the locking mechanism is designed in such a way that it is able to bring the door into the unlocked state when the unlocked state of the door is detected and the key element has been removed, and therefore brings the door into the unlocked state only after the machining operation of the machine tool has been completed or after the rotation of the spindle has been stopped, thus preventing the occurrence of unexpected accidents such as the workpiece falling, flying around and the like.

[0008] Furthermore, once the door is unlocked, it cannot be locked again until it is fully closed and the key is in the correct position. This prevents unauthorized access by accidentally closing and locking the door. Additionally, the person who accidentally closed the door can easily see that they have closed it in error, thus increasing security.

[0009] In a preferred embodiment of the present invention, the door lock mechanism has a keyhole into which the key element can be inserted, and the locking mechanism allows the door lock mechanism to bring the door into the unlocked state when the key element is removed from the keyhole.

[0010] According to the preferred embodiment, the keyhole into which the key element can be inserted is provided in the door lock mechanism so that, after the operator opens the door, even if a third person attempts to close the door with the key element still inserted in the keyhole, the door cannot be closed because the key element acts as an obstacle. This effectively prevents the third person from closing the door while the operator is working inside the machine tool. Furthermore, the third person can easily recognize that they are mistakenly attempting to lock the door, thus further enhancing security.

[0011] In another preferred embodiment of the present invention, a through-hole is formed in the door through which the key element can only be inserted into the keyhole when the door is arranged in the predetermined closed position, and the locking mechanism allows the door lock mechanism to bring the door into the unlocked state when the key element is removed from the keyhole and the through-hole.

[0012] According to another preferred embodiment, because the through-hole through which the key element can only be inserted into the keyhole of the door lock mechanism when the door is in the predetermined closed position is formed in the door, the key element itself serves as a bolt that holds the door in the closed state and can reliably prevent the door from being opened during the machining process, resulting in improved security.

[0013] Furthermore, if the door is in the open position, even if a third party mistakenly attempts to close it while the operator has left the key inserted in either the door or the lock mechanism, the door will never close because the key acts as an obstacle. This prevents the accidental locking of the door and the initiation of the operation. Meanwhile, the third party can easily recognize that they are mistakenly attempting to lock the door because they cannot close it until the key is removed, thus further enhancing security. Brief description of the drawing Fig. 1 is a front view of the machine tool according to a first embodiment of the present invention in a state in which a door of the machine tool is open; Fig. Figure 2 is a front view of the door in a closed state of the first embodiment; Fig. Figure 3 is a front view of the key element of the first embodiment; Fig. Figure 4 is a front view of a modified example of the key element of the first embodiment; Fig. Figure 5 is a sectional plan view showing the inserted state of the key element in the state that the door of the first embodiment is closed (sectional view along line VV in Fig. 2); Fig. Figure 6 is a sectional plan view showing the inserted state of the key element in the state that the door of the first embodiment is open (sectional view along line VV in Fig. 2); Fig. 7 is a front view of a machine tool according to a second embodiment of the present invention in a state in which a door of the machine tool is closed; Fig. Figure 8 is a sectional plan view showing the key element in an inserted state when the door of the second embodiment is closed (sectional view along line VIII-VIII in Figure 8). Fig. 7); Fig. Figure 9 is a front view of a machine tool according to a third embodiment, which is not part of the present invention, in a state in which a door of the machine tool is closed; and Fig. Figure 10 is a diagram showing the control flow of a locking mechanism of the third embodiment. Detailed description of preferred embodiments

[0014] Embodiments of the present invention are described below with reference to the accompanying drawings. [First embodiment]

[0015] Fig. 1 to Fig. Figure 6 shows views illustrating a machine tool according to a first embodiment of the present invention. The front, back, left, and right in this embodiment represent the front, back, left, and right as seen from the front of the machine.

[0016] In the drawings, numeral 1 denotes a machine tool. This machine tool 1 comprises a machine body 4 and a machine body cover 4a, which surrounds the machine body 4. The machine tool 1 has a machining area 2 near the center of the machine body 4, in which rotating driven spindles 2a, chucks 2b, each holding a workpiece W, tool posts (not shown), and so on are arranged. An opening 4b, corresponding to the machining area 2, in the cover 4a is designed to be opened / closed by a door 3, which separates the exterior of the machine. An operator panel 5 is arranged on a right-hand side of the machine body 4, and a flange 6, which serves as a door stop, is arranged on a right-hand edge of the opening 4b.

[0017] When a right end face 3a of the door 3 is in contact with a left end face 6a of the flange 6, a mechanism for detecting the closed state of the door 7 judges that the door 3 is in a predetermined closed position.

[0018] The mechanism for detecting the closed state of door 7, which recognizes that door 3 is in a predefined closed position, is located in an upper edge region of the right edge of the processing area 2. The mechanism for detecting the closed state of door 7 outputs a "door closed" or "door open" signal to a locking mechanism 5a described later.

[0019] A door locking mechanism 8, which locks or unlocks the door 3 from the machine body 4, is arranged on the door 3. The door locking mechanism 8 sends a "door locked" or "door unlocked" signal to the locking mechanism 5a. Furthermore, a window 3b for monitoring the processing status is provided in a central part of the door 3, and a handle 3c is attached to a right-hand side panel of the door 3.

[0020] The door lock mechanism 8 has a keyhole 8a into which a key element 9 can be inserted in a predetermined position, and the keyhole 8a is designed to extend to the left of a right end part of the door lock mechanism 8.

[0021] The key element 9, for example, is made of metal and is composed of an insert part 9a and a handle part 9b, as shown in Fig. Figure 3 shows the insertion part 9a being rod-shaped and attached to a projecting part 9c formed on the handle part 9b. Furthermore, the handle part 9b is essentially in the form of a semi-elliptical plate. Note that the handle part 9b can be formed in an essentially cuboid plate shape, which has an opening part 9d in its central section, as shown in Figure 3. Fig. 4 shown.

[0022] The flange 6 has a through-hole 6c for inserting the key element 9 and is designed such that when the door 3 is in the specified closed position, the key element 9 can be inserted into the keyhole 8a from the side of a right end face 6b of the flange 6 (see Fig. 2 and Fig. 5).

[0023] Note that the keyhole 8a is designed so that the key element 9 can be inserted even when the door 3 is in the open position. (see Fig. 6).

[0024] Furthermore, the door lock mechanism 8 transmits a signal “key inserted” to the locking mechanism 5a, indicating that the key element 9 is inserted into the keyhole 8a, or a signal “key not inserted” indicating that the key element 9 is not inserted into the keyhole 8a.

[0025] The locking mechanism 5a is located on the control panel 5. The locking mechanism 5a allows machining operations by the spindle 2a or the like when the door 3 is in the specified closed position and is locked.

[0026] In particular, the locking mechanism 5a allows the door lock mechanism 8 to unlock the door 3 when the unlocking condition of the door 3 is established and the key element 9 is removed from the keyhole 8a of the door lock mechanism 8. Once the door 3 is unlocked, the locking mechanism 5a allows the door lock mechanism 8 to lock the door 3 only when the key element 9 is inserted into the keyhole 8a of the door lock mechanism 8 in a state where the door 7's closed-state detection mechanism recognizes that the door 3 is in the specified closed position.

[0027] The unlocking condition of door 3 refers, for example, to the case where all machining operations of the workpiece are completed or the case where the workpiece machining is interrupted halfway through and the rotation of spindle 2a or the like is stopped.

[0028] In the first embodiment of the machine tool 1, in order to unlock the door 3, the operator must, after the unlocking condition has been established, remove the key element 9 from the keyhole 8a, i.e., from its predetermined position, through the through-hole 6c. During the removal of the key element 9, the operator will hold it in their hand. The operator then opens the unlocked door 3, enters the machine tool 1 while holding the key element 9, and performs the work.

[0029] During operation, the locking mechanism 5a, even if a third person mistakenly moves the door 3 into the specified closed position for the execution of the operation, never allows the locked state of the door 3 to be disengaged until the key element 9, held by the operator, is inserted through the through hole 6c into the keyhole 8a.

[0030] Furthermore, if the operator enters the machine tool 1 and performs the work while the key element 9 remains inserted in the keyhole 8a of the door 3 which is in the open position, the handle part 9b of the key element 9 is an obstacle, so that the door 3 can never be brought into the specified closed position, even if the third person mistakenly tries to close the door 3.

[0031] According to the first embodiment, the locking mechanism 5a brings the door 3 into the unlocked state when the unlocking condition of the door 3 is established and the key element 9 is removed, and therefore the door 3 is only brought into the unlocked state after the machining operation of the machine tool 1 has ended or the rotation of the spindle 2a has been stopped, and thus the occurrence of unexpected accidents, such as the workpiece falling, flying around and the like, can be prevented.

[0032] Furthermore, once door 3 has been unlocked, it cannot be locked again until it is moved to the closed position and key element 9 is inserted. This prevents the process from starting even if a third party accidentally closes door 3. Additionally, the third party can easily recognize that they have closed the door by mistake, thus increasing security.

[0033] Furthermore, if door 3 is in the open position, even if the third person attempts to close door 3 with the key element 9 remaining inserted in the keyhole 8a, door 3 will never be brought into the closed position because the key element 9 is an obstacle, so that even in this case it is possible to prevent door 3 from being accidentally closed and processing being started. [Second embodiment]

[0034] Fig. 7 to Fig. Figure 8 are views illustrating a machine tool according to a second embodiment of the present invention. In the drawings, the same numbers or letters denote the positions as in Fig. 1 to Fig. 6 the same or corresponding components.

[0035] In the second embodiment of the machine tool 1, a rightward-projecting protruding part 11 is formed in a central section at a right end region of the door 3. A through-hole 11a for inserting a key element 12 is formed in a central section of the protruding part 11. Furthermore, the protruding part 11 is arranged at the front of a right edge region of the machining area 2 when the door 3 is in the specified closed position.

[0036] A door lock mechanism 13 is embedded in a central part of the machine body 4 in a right-hand edge region of the machining area 2. The door lock mechanism 13 has a keyhole 13a into which the key element 12 can be inserted, and the keyhole 13a extends from the front of the machine to the rear.

[0037] When the door 3 is in the specified closed position, the through-hole 11a aligns with the keyhole 13a, and the key element 12 can then be inserted through the through-hole 11a into the keyhole 13a, serving as a so-called bolt. Furthermore, the key element 12 is, for example, made of metal and is essentially in the form of a rod.

[0038] The locking mechanism 5a allows the door lock mechanism 13, in the state where the unlocking condition is detected and the key element 12 is removed from the keyhole 13a and the through-hole 11a, to bring the door 3 into the unlocked state, and after the door 3 is unlocked, the locking mechanism 5a allows the door lock mechanism 13 to bring the door 3 into the locked state only if, in the state where the mechanism for detecting the closed state of the door detects that the door 3 is in the specified closed position, the key element 12 is inserted into the keyhole 13a of the door lock mechanism 13.

[0039] According to the second embodiment, when the door 3 is arranged in the specified closed position, the key element 12 is inserted into the keyhole 13a through the through-hole 11a of the door 3 and serves as a bolt, and can therefore safely protect the door 3 from being opened unintentionally during the processing process.

[0040] Furthermore, in the second embodiment as well, the door 3 can be opened in the state that the unlocked state of the door 3 is determined and when the key element 12 is removed, as in the first embodiment, so that the door 3 is secured against opening during the processing operation and security can also be improved by this point.

[0041] Furthermore, once door 3 is opened, it will never be brought into the locked position until door 3 is moved into the closed position and the key element 12 is inserted, thus preventing door 3 from being accidentally closed and processing from starting, resulting in improved security.

[0042] Furthermore, even if a third party mistakenly attempts to close the door when the key element 12 remains inserted in either the door 3 or the door lock mechanism 13, the door 3 will never be moved into the closed position because the key element 12 acts as an obstacle. This prevents the door from being accidentally locked and the attempt to tamper with it. Moreover, the third party can easily recognize that they are mistakenly attempting to lock the door, thus enhancing security.

[0043] Note that the door lock mechanism 13 is recessed into the machine body 4, and the projecting part 11 with the through-hole 11a formed therein is provided on the door 3 in the second embodiment. However, the door lock mechanism 13 can, of course, also be recessed into the door 3, and the projecting part 11 with the through-hole 11a formed therein can be provided on the machine body 4, so that the key element 12 can only be inserted when the door 3 is in the predetermined closed position. [Third embodiment]

[0044] Fig. 9 to Fig. Figure 10 are views illustrating a machine tool according to a third embodiment, which is not part of the present invention. In the drawings, the same numbers or letters denote the dimensions as those in Fig. 1 to Fig. 8 the same or corresponding components.

[0045] In the machine tool 1 of the third embodiment, a key element 21 is designed to transmit a "plugged in" signal (electronic information) indicating that the key element 21 is plugged in when it is inserted into a predefined attachment 22. The locking mechanism 5a further includes a receiver 5b that receives the "plugged in" signal from the key element 21. The key element 21, for example, is designed in an essentially rectangular card shape. Furthermore, the attachment part 22 is designed in an essentially cuboid shape and has an inlet into which the key element 21 can be inserted.

[0046] The locking mechanism 5a allows the door lock mechanism 8 to bring the door into the locked state only when the locking mechanism 5a is changed from a state in which it does not receive the signal “inserted” from the key element 21 to a state in which it does receive the signal “inserted”, in which the mechanism for detecting the closed state of the door 7 recognizes that the door 3 is in the specified closed position.

[0047] The process of closing / unlocking the door of machine tool 1 in the third embodiment is described using a flowchart in Fig. 10 described.

[0048] In a state where the unlocking condition of door 3 is established (step S1), when the operator removes the key element 21 from the attachment 22, the predefined electronic information (signal "inserted") from the key element 21 to the receiver 5b is stopped (step S2). Then, the locking mechanism 5a allows the door lock mechanism 8 to move door 3 to the unlocked state, and the door lock mechanism 8 unlocks door 3 (step S3). Thus, the operator can open door 3, which has been moved to the unlocked state, enter the machine tool 1 holding the key element 21, and perform the work.

[0049] Once the work is completed, when the operator moves door 3 into the specified closed position, the mechanism for detecting the closed state of door 7 transmits the "closed" signal of door 3 to the locking mechanism 5a (step S4).

[0050] Since the operator is holding the key element 21, the "inserted" signal from the key element 21 to the receiver 5b is still paused (step S5). However, when the operator inserts the key element 21, which they are holding, into the attachment 22, the receiver 5b receives the "inserted" signal from the key element 21 (step S6). This allows the locking mechanism 5a to permit the door lock mechanism 8 to bring the door 3 into the locked position, and the door lock mechanism 8 locks the door 3 (step 7), so that processing can begin.

[0051] As described above, even if a third person mistakenly moves door 3 into the designated closed position to lock it while the operator is working in machine tool 1, door 3 will never lock until the key element 21, held by the operator, is inserted into the attachment 22. Consequently, it is possible to prevent accidental starting of the machining process, thus guaranteeing safety.

[0052] When the operator opens door 3 (steps S1 to S3) and then reinserts the key element 21 into the attachment 22 and enters the machine tool 1 in this state, the receiver 5b continues to receive the "inserted" signal from the key element 21.

[0057] Even if the third person moves door 3 into the specified closed position in this state, the receiver 5b continues to receive the "plugged in" signal from the key element 21, and therefore the process never continues with step S6, and door 3 is therefore never mistakenly locked.

[0053] Note that to lock door 3, the operator only needs to remove the key element 21 from the attachment 22 and then reinsert it into the attachment 22. This allows the locking mechanism 5a to enable the door lock mechanism 8 to lock door 3 as described above (steps S5 to S7).

[0054] According to the third embodiment, opening the door by removing the key element 21 from the attachment 22 is permitted when the unlocking condition is established, and closing the door is only permitted when the door is closed and the key element 21 is reinserted, so that a simple design can be used to prevent the door 3 from being mistakenly placed in the unlocked or locked state.

[0055] Furthermore, since the door locking mechanism 8 is designed to only bring the door into the locked state when the receiving part 5b changes from the state in which it does not receive the signal “plugged in” to the state in which it receives the signal “plugged in”, even if the door 3 is moved into the predetermined closed position, it is possible to prevent the door from being mistakenly brought into the locked state and the processing being started, even if the operator enters the machine leaving the key element 21 in the attachment 22, which leads to improved security.

Claims

[1] Machine tool (1), comprising: a door (3) designed to separate a processing area (2) and an exterior of the machine and to be openable / closable; a mechanism (7) for detecting the closed state of the door (3), which detects that the door (3) is in a predetermined closed position; a door locking mechanism (8, 13) that locks or unlocks the door (3); and a locking mechanism (5a) that permits operation when the door (3) is in a predetermined closed position and is in a locked state, and allows the door lock mechanism (8, 13) to bring the door (3) into an unlocked state in a state in which an unlocking condition of the door (3) is detected and when a key element (9, 12) is removed from a predetermined position, and, after the door (3) is unlocked, allows the door lock mechanism (8, 13) to bring the door (3) into the locked state only when the key element (9, 12) is inserted into the predetermined position in a state in which the mechanism (7) for detecting the closed state of the door (3) detects that the door (3) is in the predetermined closed position, wherein the key element (9, 12) constitutes an obstacle that is designed to preventthat the door (3) is brought into the specified closed position when the key element (9, 12) is in the specified position in an open state of the door (3). [2] Machine tool according to claim 1, wherein the door lock mechanism (8, 13) has a keyhole (8a, 13a) into which the key element (9, 12) can be inserted, and wherein the locking mechanism (5a) allows the door lock mechanism (8, 13) to bring the door (3) into the unlocked state when the key element (9, 12) is removed from the keyhole (8a, 13a). [3] Machine tool according to claim 2, wherein a through hole (6c, 11a) through which the key element (9, 12) can only be inserted into the keyhole (8a, 13a) when the door (3) is in the predetermined closed position is formed in the door (3), and wherein the locking mechanism (5a) allows the door lock mechanism (8, 13) to bring the door (3) into the unlocked state when the key element (9, 12) is removed from the keyhole (8a, 13a) and the through hole (6c, 11a).

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