PROTECTIVE DOOR DEVICE AND PROTECTIVE DOOR LOCKING METHOD

Abstract

A safety door device with a full closing detector (44) configured to detect that a protective door (30) has fully closed from an open state; a locking mechanism (46) configured to lock the safety door so that the safety door cannot be opened; a measuring unit (accelerometer (36), control unit (50)) configured to measure a motion acceleration (α), a motion velocity (V) or a motion time (T) when the safety door closes; and a control unit (50) configured to control the locking mechanism to lock the safety door when it is determined that the safety door is fully closed, wherein the control unit is further configured not to cause the safety door to lock if the acceleration or speed of movement is greater than a first threshold (α1, V1) or if the time of movement is shorter than a second threshold (T1).

Description

BACKGROUND OF THE INVENTION: Field of invention:

[0001] The present invention relates to a safety door device for ensuring occupational safety and a method for locking the safety door. Description of the state of the art:

[0002] A machine can be equipped with a safety door to ensure operator safety (see, for example, Japanese patent publication JP 2010-5759A). Machines such as machine tools, injection molding machines, presses, etc., have working areas where cutting tools or molds operate, and it would be dangerous if a worker, for example, put their hand into such an area. The safety door closes off the working area while the machine is in operation to ensure operator safety. That is, an interlocking mechanism works to lock the safety door when it is closed, and the machine then starts operating. SUMMARY OF THE INVENTION

[0003] However, if a safety door is closed quickly, the locking mechanism, etc., will be subjected to an impact when the safety door slams shut and may be damaged.

[0004] One object of the present invention is to provide a protective door device and a protective door locking method that prevent damage when the protective door is closed quickly.

[0005] A safety door device according to one aspect comprises a full-closing detector configured to detect that a safety door has fully closed from an open state; a locking mechanism configured to lock the safety door so that it does not open; a measuring unit configured to measure a motion acceleration, motion velocity, or motion time as the safety door closes; and a control unit configured to control the locking mechanism to lock the safety door when it detects that the safety door is fully closed, the control unit further being configured not to cause the safety door to lock if the motion acceleration or motion velocity is greater than a first threshold or if the motion time is less than a second threshold.

[0006] The present invention thus provides a protective door device and a protective door locking method that prevents damage when the protective door is closed quickly.

[0007] The above and further tasks, features and advantages of the present invention will become even clearer from the following description in conjunction with the accompanying drawings, in which a preferred embodiment of the present invention is illustrated by way of example. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic figure showing a machine configuration of a machine device equipped with a safety door according to one embodiment; Fig. Figure 2 is a block diagram illustrating a control configuration of the machine unit equipped with a safety door; Fig. 3A, Fig. 3B and Fig. Figures 3C are schematic diagrams that depict a key switch in detail; and Fig. Figure 4 is a flowchart showing an example of an operating sequence for the machine equipment equipped with a safety door. DESCRIPTION OF PREFERRED EXECUTION FORMS

[0008] In the following, a machine device 10 equipped with a protective door and a method for locking a protective door 30 according to one embodiment are described. Fig. 1 and Fig. Figure 2 shows a machine configuration or a control configuration of the machine unit 10 of the embodiment equipped with a protective door.

[0009] As in Fig. As shown in Figure 1, the machine unit 10, equipped with a safety door, has a machine unit body (not shown) installed within a cover 20, and an opening 22 of this body is opened and closed by the safety door 30. The machine unit 10, equipped with a safety door, also has a safety door device 12 (see Figure 1). Fig. 2) which opens, closes and locks the safety door 30 and controls these operations. The safety door device 12 comprises a full-opening detector 26, a key 34, an acceleration sensor 36, a key switch 40 (a full-close detector 44, a locking mechanism 46), a control unit 50 and a notification unit 52.

[0010] The full-opening detector 26 is a contact switch or proximity switch, which is provided, for example, on the cover 20 and is located near or in contact with the safety door 30 when the safety door 30 is fully open, and detects that the safety door 30 is fully open. When the detection state of the full-opening detector 26 changes from detection of full opening to its non-detection, this means that the safety door 30 has started to move (detection of the start of movement).

[0011] The key 34 is held so that it protrudes from the protective door 30 (see Fig. 1) When the safety door 30 is closed, the key 34 is inserted into a key insertion opening 42 of the key switch 40; when the safety door 30 is opened, the key 34 is withdrawn from the key insertion opening 42.

[0012] The acceleration sensor 36 (measuring unit) is provided on the safety door 30 and detects a motion acceleration α acting on the safety door 30.

[0013] The key switch 40 (full closing detector 44, locking mechanism 46) detects the complete closing of the safety door 30 and locks the safety door 30 with the key 34.

[0014] In the Fig. Figures 3A to 3C show the internal structure of the key switch 40. Fig. Figures 3A to 3C show the states of the key switch 40 (1) before inserting the key 34 (after the key 34 has been removed), (2) after inserting the key 34, (3) after inserting and locking the key 34.

[0015] The full-closing detector 44 is, for example, a contact switch or a proximity switch and is located near or in contact with the key 34 when the safety door 30 is fully closed (when the key 34 is fully inserted into the key insertion hole 42: see Fig. 3B) and recognizes that the safety door 30 is completely closed.

[0016] The locking mechanism 46 is, for example, an electromagnetic magnet that moves a locking element 46a downwards when it is energized, and moves the locking element 46a upwards with a preloading element, such as a spring, when it is not energized. When the safety door 30 is fully closed (see Fig. 3B), the locking mechanism 46 is supplied with power and then the locking element 46a engages in an engagement section 341 of the key 34 (see Fig. 3C). In this way, the locking mechanism 46 can switch the safety door 30 between a locked state (the safety door 30 cannot be opened) and an unlocked state (the safety door 30 can be opened), depending on whether it is supplied with power or not.

[0017] The control unit 50 controls the key switch 40 to protect the safety door device 12 when the safety door 30 closes rapidly. This process will be described in detail later. The control unit 50 consists of hardware (CPU: central processing unit) and software; for example, a control unit of the machine body can also serve as the control unit 50.

[0018] The notification unit 52 is, for example, a display unit (e.g., a liquid crystal display) that shows a warning message when the safety door 30 closes rapidly. The notification unit 52 may, instead of or in addition to the display unit, include an audio output device for emitting sound (e.g., a loudspeaker), which can emit a warning message with sound. (Details of control unit 50)

[0019] The details of the control unit (control device) 50 are described below.

[0020] When a complete closure of the safety door 30 is detected, the control unit 50 controls the locking mechanism 46 to lock the safety door 30.

[0021] However, even if the safety door 30 is detected to be fully closed, the control unit 50 will not lock the safety door 30 if the acceleration of movement α is greater than a threshold value α1 (first threshold value). In this case, the control unit 50 generates a warning signal. Based on this warning signal, the notification unit 52 generates a warning message with image or sound.

[0022] If, on the other hand, the acceleration of motion α is equal to or less than the threshold α1 (first threshold), the control unit 50 controls the locking mechanism 46 to lock the safety door 30 when a complete closure of the safety door 30 is detected.

[0023] Fig. Figure 4 is a flowchart showing an example of the operating sequence of machine unit 10 equipped with a safety door. The operating sequence of machine unit 10 equipped with a safety door is described with reference to Fig. 4 described.

[0024] A process to close the safety door 30 is initiated (step S1). For example, the safety door 30 is manually opened in the closing direction (in Fig. 1 (here to the right) is moved. Alternatively, the control unit 50 can move the safety door 30 by controlling a motor.

[0025] The accelerometer 36 (measuring unit) measures the motion acceleration α (step S2), and the control unit 50 determines whether the motion acceleration α is greater than the threshold value α1 (step S3). If the motion acceleration α is greater than the threshold value α1, the control unit 50 generates a warning signal (step S4).

[0026] The key 34 is then inserted into the key insertion opening 42 while the safety door 30 moves in the closing direction. The full-closing detector 44 then switches to the ON state and detects that the safety door 30 is completely closed.

[0027] If the acceleration of movement α is equal to or less than the threshold value α1, the control unit 50 supplies current to the locking mechanism 46 upon detection of complete closure, thereby locking the safety door 30 (step S5). If, on the other hand, the acceleration of movement α is greater than the threshold value α1, the control unit 50 does not initiate locking of the safety door 30, even if complete closure is detected.

[0028] For safety reasons, even if the acceleration of movement α is equal to or less than the threshold α1, the control unit 50 cannot lock the safety door 30 immediately after detecting that the safety door 30 is completely closed, but only after a certain time (e.g. 0.1 to 1 second) has passed since the detection of the complete closure.

[0029] As described above, the machine unit 10, equipped with the safety door, locks the safety door 30 when the acceleration α of the safety door 30 is equal to or less than the threshold α1 when the safety door 30 is fully closed. However, the machine unit 10 does not lock the safety door 30 if the acceleration α is greater than the threshold α1. This reduces the possibility of damage to the safety door device 12 that could be caused by an impact during the rapid closing of the safety door 30.

[0030] If the acceleration of movement α is greater than the threshold value α1, the safety door device 12 can be damaged by an impact when the safety door 30 bounces. That is, locking the safety door 30 when it is fully closed can damage the key 34 or the locking mechanism 46, regardless of the acceleration of movement α. (First modification)

[0031] A first modification is now described. The embodiment above controls the locking of the safety door 30 via the acceleration of movement α. The first modification controls the locking of the safety door 30 via a movement time T of the safety door 30.

[0032] The movement time T can be measured as the time T from the start of the movement of the safety door 30 until the detection of complete closure of the safety door 30. This time measurement can be performed by the control unit 50. That is, a part of the control unit 50 can function as a timer unit for measuring the time T until the detection of complete closure of the safety door 30.

[0033] The start of the movement of the safety door 30 can be determined, for example, by the following methods 1) and 2). 1) Acceleration detection

[0034] The start of movement of the safety door 30 can be determined by the acceleration sensor 36 detecting an acceleration value α that exceeds a detection error (threshold α2). That is, the control unit 50 compares the acceleration α detected by the acceleration sensor 36 with the threshold value α2 and determines that the movement of the safety door 30 has begun when the acceleration α exceeds the threshold value α2. The threshold value α2, used to determine whether the safety door 30 has started moving, is lower than the threshold value α1, used to determine whether the safety door 30 should be locked. 2) Failure to detect full opening

[0035] The start of the movement of the safety door 30 can also be determined when the full-opening detector 26 loses its detection of the safety door 30 being fully open (non-detection of full opening). That is, the control unit 50 detects that the state of the full-opening detector 26 has changed from detection of full opening to non-detection.

[0036] For example, the control unit 50 can determine the movement time T as the difference between a time t0 of the start of the movement of the safety door 30 and a time t1 of the detection of the complete opening of the safety door 30. T=t1−t0

[0037] Alternatively, the controller 50 can also determine the movement time T directly, without determining the individual times t0 and t1, e.g. by starting a timer when a movement start is detected and stopping the timer when the complete closing is detected.

[0038] Now, an operating sequence of the machine unit 10 of the first modification, equipped with a safety door, is described. The machine unit 10 of the first modification, equipped with a safety door, operates similarly to the machine unit 10 of the embodiment equipped with a safety door, except that it uses the movement time T instead of the movement acceleration α to determine whether it is locked. Accordingly, the difference is mainly with regard to Fig. 4 described.

[0039] The first modification differs from the embodiment in steps S2, S3, whereby the detection and determination is carried out with the movement time T instead of the movement acceleration α.

[0040] As explained above, the control unit 50 determines the movement time T as the time T from the start of the movement of the safety door 30 until the detection of the complete closing of the safety door 30 (detection of complete closing (step S2)).

[0041] The control unit 50 determines whether the movement time T is less than a threshold value T1 (second threshold: T < T1? (step S3)). If the movement time T is less than the threshold value T1 (second threshold), the control unit 50 generates a warning signal (step S4) and does not initiate locking of the safety door 30, even if complete closure is detected. If the movement time T is equal to or greater than the threshold value T1 (second threshold), then the control unit 50 initiates locking of the safety door 30 when complete closure is detected (or when a certain time has elapsed after detection (step S5)). (Second modification)

[0042] A second modification is now described. The implementations above used the acceleration of movement α or the movement time T to control the locking of the safety door 30. The second modification uses a movement speed V of the safety door 30 to control the locking of the safety door 30.

[0043] The speed of movement V can be determined, for example, by the following methods 1) and 2). 1) Integration of the acceleration

[0044] The control unit 50 can calculate the movement speed V(t) of the safety door 30 by integrating the movement acceleration α(t) detected by the acceleration sensor 36 over time (integration over time t). V(t)=∫α(t)⋅dt

[0045] In this case, the control unit 50 can calculate the change in the speed of movement V(t) over time. 2) Calculation from the movement time T

[0046] The control unit 50 can obtain the movement speed V by dividing a movement path L of the safety door 30 by the movement time T obtained by method 1) or 2) of the first modification. V=L / T

[0047] The movement path L can be a suitable fixed value corresponding to the machine device 10 equipped with a protective door.

[0048] The second modification does not differ significantly from the embodiment, except that the movement speed V is used instead of the movement acceleration α to determine whether locking should occur. That is, it is determined whether the movement speed V is greater than a threshold value V1 (first threshold: V > V1? (step S3)). If the movement speed V is greater than the threshold value V1 (first threshold), the control unit 50 generates a warning signal (step S4) and does not cause the safety door 30 to lock, even if complete closure is detected. If the movement speed V is equal to or less than the threshold value V1 (first threshold), then the control unit 50 causes the safety door 30 to lock when complete closure is detected (step S5).

[0049] As described above, the control unit 50 causes the safety door 30 to lock depending on the acceleration α, the travel time T, or the speed V of the safety door 30. This reduces the possibility of damage to the locking mechanism, etc., from an impact of the safety door 30. That is, the acceleration α, the travel time T, and the speed V can be used as physical quantities that correspond to the magnitude of the impact when the safety door 30 bounces.

[0050] The invention encompassed by the embodiments and modifications described above can be summarized as follows.

[0051] [1] A safety door device (12) comprises: a full-closing detector (44) configured to detect that a safety door (30) is fully closed from an open state; a locking mechanism (46) configured to lock the safety door so that it does not open; a measuring unit (accelerometer 36, control unit 50) configured to measure a motion acceleration (α), motion velocity (V), or motion time (T) as the safety door closes;and a control unit (50) configured to control the locking mechanism to lock the safety door when it is detected that the safety door is fully closed, the control unit further being configured not to cause the safety door to lock if the acceleration or speed of movement is greater than a first threshold (α1, V1) or if the time of movement is shorter than a second threshold (T1).

[0052] Thus, the safety door will not lock if the acceleration or speed of movement is greater than the first threshold or the time of movement is less than the second threshold, thereby reducing the possibility of damage to the safety door device.

[0053] [2] The controller generates a warning signal if the acceleration α of the movement or the speed of the movement is greater than the first threshold or if the time of the movement is less than the second threshold.

[0054] This makes it possible to issue a warning of potential damage to the safety door mechanism. Based on this warning signal, a warning message with an image or sound can be generated.

[0055] [3] The measuring unit can assume the following configurations. (1) Measurement of motion acceleration

[0056] The measuring unit contains an acceleration sensor configured to detect any acceleration of movement acting on the safety door. (2) Measurement of movement time

[0057] a) The measuring unit comprises: a full-opening detector (26) configured to detect when the safety door is fully open; and a timing unit configured to measure the movement time from the time when the safety door is not fully open until the safety door is fully closed. The safety door device can thus be secured without the use of an accelerometer.

[0058] b) The measuring unit comprises: an accelerometer configured to detect a motion acceleration acting on the safety door; and a timing unit configured to measure the time from the moment the accelerometer detects the motion acceleration until the full-closing detector detects that the safety door is fully closed. The safety door device can thus be secured based on the motion time without using a full-opening detector. (3) Measurement of the speed of movement

[0059] a) Calculation of velocity from motion acceleration The measuring unit contains an integrator configured to calculate the motion velocity by integrating the motion acceleration detected by the accelerometer. b) Calculation of speed based on the time of travel

[0060] The measuring unit may also include a divider configured to calculate the velocity (V) by dividing the distance traveled (L) of the closing of the safety door by the travel time (T).

[0061] [4] The control unit initiates the locking of the safety door when a certain time has elapsed after the detection of the safety door being fully closed, when the acceleration or speed of movement is equal to or less than the first threshold, or when the time of movement is equal to or greater than the second threshold.

[0062] This allows for a secure locking process, as the safety door locks after a certain time has elapsed following the detection of complete closure.

[0063] [5] A locking method for a safety door uses a safety door device that includes a full-closing detector configured to detect when a safety door has fully closed from an open state, and a locking mechanism configured to lock the safety door so that it does not open. The safety door locking method comprises the following steps: measuring a motion acceleration, motion velocity, or motion time as the safety door closes; and controlling the locking mechanism to lock the safety door when it is detected that the safety door is fully closed, and to not lock the safety door if the motion acceleration or motion velocity is greater than a first threshold or if the motion time is less than a second threshold.

[0064] Thus, the safety door will not lock if the acceleration or speed of movement is greater than the first threshold or if the movement time is shorter than the second threshold, thereby reducing the possibility of damage to the safety door device.

[0065] [6] The safety door locking procedure further includes the step of generating a warning signal if the acceleration or speed of movement is greater than the first threshold or if the time of movement is less than the second threshold. This makes it possible to warn that the safety door device may be damaged. Based on this warning signal, a warning message with a picture or sound can be generated.

[0066] [7] The safety door device further comprises a full-opening detector (26) configured to detect when the safety door is fully open, and in the measuring step of the safety door locking procedure, the time from when the full opening of the safety door was not detected until when the full closing of the safety door is detected is measured as the movement time. The safety door device can thus be secured without the use of an acceleration sensor.

[0067] [8] The safety door locking procedure includes the step of locking the safety door when a certain time has elapsed after the detection of the safety door being fully closed, when the acceleration or speed of movement is equal to or less than the first threshold, or when the time of movement is equal to or greater than the second threshold. Thus, a safe locking process is possible by locking the safety door after a certain time has elapsed following the detection of its being fully closed.

Claims

[1] A safety door device with a full closing detector (44) configured to detect that a protective door (30) has fully closed from an open state; a locking mechanism (46) configured to lock the safety door so that the safety door cannot be opened; a measuring unit (accelerometer (36), control unit (50)) configured to measure a motion acceleration (α), a motion velocity (V) or a motion time (T) when the safety door closes; and a control unit (50) configured to control the locking mechanism to lock the safety door when it is determined that the safety door is fully closed, wherein the control unit is further configured not to cause the safety door to lock if the acceleration or speed of movement is greater than a first threshold (α1, V1) or if the time of movement is shorter than a second threshold (T1). [2] Protective door device according to claim 1, wherein the control unit is configured to generate a warning signal when the acceleration of movement or the speed of movement is greater than the first threshold or when the time of movement is shorter than the second threshold. [3] The protective door device according to claim 1 or 2, wherein the measuring unit comprises a full-opening detector configured to detect when the safety door is fully open; and a timing unit configured to measure as movement time the time from the time when the full opening of the safety door is no longer detected until the time when the full closing of the safety door is detected. [4] Safety door device according to one of claims 1 to 3, wherein the control unit is configured to cause the safety door to lock when a certain time has elapsed after the detection of the safety door being fully closed, when the acceleration or speed of movement is equal to or less than the first threshold, or when the time of movement is equal to or longer than the second threshold. [5] A method for locking a safety door, which uses a safety door device comprising a full-closing detector configured to detect that a safety door has fully closed from an open state and a locking mechanism configured to lock the safety door so that the safety door does not open, wherein the method for locking the safety door comprises the following steps: Measuring acceleration, velocity, or time of movement as the safety door closes; and Controlling the locking mechanism to lock the safety door when it is determined that the safety door is fully closed, and to prevent the safety door from locking if the acceleration or speed of movement is greater than a first threshold, or if the time of movement is shorter than a second threshold. [6] Method for locking the safety door according to claim 5, further comprising a step for generating a warning signal if the acceleration of movement or the speed of movement is greater than the first threshold or if the time of movement is shorter than the second threshold. [7] Method for locking the safety door according to claim 5 or 6, wherein the safety door device further comprises a full opening detector configured to detect that the safety door is fully open, and wherein in the measuring step a time from the time at which the full opening of the safety door was not detected until the time at which the full closing of the safety door is detected is measured as the movement time. [8] Method for locking the safety door according to any one of claims 5 to 7, further comprising a step for locking the safety door when a certain time has elapsed after the detection of the safety door being completely closed, when the acceleration of movement or the speed of movement is equal to or less than the first threshold, or when the time of movement is equal to or longer than the second threshold.

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