JP4159232B2 - Safety equipment for grinding machines - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a safety device for a grinding machine, and more particularly to a safety device for a grinding machine in which a grinding wheel is rotationally driven in a case having an opening / closing door.
[0002]
[Prior art]
Conventionally, there is a grinding machine in which a grinding wheel is driven to rotate in a case to grind a workpiece. The grinding machine includes a motor that rotates the grinding wheel by supplying power and stops the rotation by stopping supplying power. Further, the case has an opening for maintenance work or workpiece supply, and is provided with an opening / closing door for opening and closing the opening. The opening / closing door closes the opening during grinding, and is opened when maintenance work or work replacement is performed.
[0003]
[Problems to be solved by the invention]
However, since the grinding wheel has a predetermined weight and is driven to rotate at a high speed, even after the power supply to the motor is stopped by the rotation stop operation, the grinding wheel continues to rotate for a while by the inertial force. Therefore, there is a concern that after the rotation stop operation, an operator mistakenly opens the open / close door during inertial rotation of the grinding wheel.
[0004]
Therefore, the objective of this invention made | formed in view of this point is providing the safety device of the grinding machine which can open an opening-and-closing door only when the grinding stone is stopped rotating.
[0007]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a safety device for a grinding machine in which a grinding wheel is rotationally driven in a case having an opening / closing door, a rotation detecting means for repeatedly outputting different signals in synchronization with the rotation of the grinding wheel, and the opening / closing door and locking means for locking the, the first after a set time the rotation of the grinding wheel from the grinding machine stop operation has been set in advance as the time required to stop, the same signal state from the rotation detecting means is set in advance And a locking control means for enabling the unlocking operation of the locking means when continuing for the second set time.
[0008]
According to the present invention, the first after a set time the rotation of the grinding wheel from the grinding machine stop operation has been set in advance as the time required to stop, setting the same signal state from the rotation detecting means in advance Since the unlocking operation of the locking means is enabled when the second setting time is continued, the opening / closing door can be opened only after the rotation of the grinding wheel is reliably stopped, and maintenance work can be performed from the opening. It is possible to ensure the safety of workers who perform work or work replacement. Incidentally, the first set time is a time in which the rotation of the grinding wheel can no observed to have stopped from rotation stop operation, is determined in advance by simulation or experiments.
[0009]
In the safety device for a grinding machine according to the second aspect of the invention, the rotation detecting means repeatedly outputs ON / OFF in synchronization with the rotation of the grinding wheel, and the locking control means is used to stop the grinding wheel from the stop operation of the grinding machine . solution when the rotation after a first set time that is set in advance as the time required to stop, one of the oN state and OFF of the rotation detecting means has continued second set time set in advance It is characterized by enabling the lock operation.
[0010]
The invention of claim 2 specifically shows the invention of claim 1 , and the elapse of a first set time set in advance as a time required from the grinding machine stop operation until the rotation of the grinding wheel stops. Later, since the unlocking operation is validated when either the ON or OFF state continues from the rotation detecting means for the second set time, monitoring is performed based on ON / OFF from the rotation detecting means. The rotation state of the grinding wheel can be easily detected, and the rotation stop judgment of the grinding wheel can be easily performed with a simple configuration and control processing.
[0011]
According to a third aspect of the present invention, there is provided a safety device for a grinding machine, wherein the rotation detecting means is turned on and off by a protrusion that rotates in conjunction with a grinding wheel and a non-rotating member that is fixed to the protrusion. It is a proximity sensor that performs switching.
[0012]
According to the invention of claim 3, since the rotation detection means is formed by the proximity sensor and the protrusion, it can be provided at low cost by utilizing the existing proximity sensor.
[0013]
According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the locking control means detects the unlocking signal to the locking means only when the grindstone complete stop state is detected and there is a request for unlocking. The locking means is composed of a rod protruding type actuator at all times, and only when an unlocking signal is outputted from the locking control means, the rod can be retracted to open the door.
[0014]
According to the fourth aspect of the invention, the unlocking signal is output from the locking control means to the actuator as the locking means only when the grindstone complete stop state is detected and there is a request for unlocking. And, the actuator is always a rod protruding type, and only when the unlocking signal is output from the locking control means, the rod can be retracted to open the open / close door, so when a power failure occurs during grinding operation or grinding, etc. Even if an operator tries to open the door, the door is locked by the rod protruding from the actuator, and if the grinding wheel is rotating by inertia, the door can be reliably prevented from opening. Can ensure safety.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of a grinding machine 1 according to the present embodiment, and reference numeral 3 in the drawing is a control board for controlling the grinding machine 1. The grinding machine 1 has two motors 5 on a base 4 that is installed and fixed on a floor surface (not shown).
[0016]
The motors 5 are arranged so that their rotational axes are substantially horizontal and coaxially opposed to each other, and a disk-shaped grinding wheel 10 is coupled to each motor 5 via an attachment 7. The attachment 7 has one end fixed to the center of the grinding wheel 10 and the other end attached to a rotation shaft (not shown) of the motor 5 so as to be movable along the axial direction. In addition, an actuator (not shown) is connected to the attachment 7, and the grinding wheel 10 can be moved in the direction of an arrow X to approach or separate from each other in a rotating state by operating the actuator.
[0017]
A case 12 is provided on the base 4 so as to cover the periphery of the grinding wheel 10 at a position between the two motors 5 arranged to face each other. The case 12 has a box shape with an open lower surface, and an opening 15 for maintenance such as replacement of the grinding stone 10 is formed on the upper surface 14 and is closed by an opening / closing door 16.
[0018]
One side of the opening / closing door 16 is pivotally supported on the upper surface 14 of the case 12, and an opening / closing handle 17 and a safety plug 18 are provided on the other side. The safety plug 18 can be held in a socket (not shown) provided on the case 12 side by closing the opening / closing door 16, and is always removed from the socket by opening the opening / closing door 16, and by removing the safety plug 18, The main power supply is cut off.
[0019]
A cylinder lock (locking means) 20 including an actuator such as an electromagnetic solenoid that locks the opening / closing door 16 is provided on the upper portion of the case 12. The cylinder lock 20 is always a rod protruding type and protrudes by the urging force of a cylinder main body 21 fixed to the case 12 and a spring (not shown) provided in the cylinder main body 21, and the grindstone is completely stopped by the processing described later. An electromagnetic coil (not shown) in the cylinder body 21 is detected only when a state is detected and a control signal (unlock signal; ON) is output from the control unit 40 of the control panel 3 in response to an unlock request by turning on the unlock button 35. The rod 22 is energized and retracted by the exciting force of the coil. The rod 22 projects above the closed door 16 to lock the door 16 and prevent its opening.
[0020]
In addition, an opening hole (not shown) for inserting a workpiece W as an object to be ground is provided between the opposing grinding wheels 10 on the back surface (not shown) of the case 12. The workpiece W to be ground in the present embodiment is a brake disc of an automobile, and as shown in the drawing, both disc surfaces Wa and wb are held in a posture in which they are in contact with and sandwiched with each grinding wheel 10. .
[0021]
2A and 2B are explanatory views of the rotation detecting means, in which FIG. 2A is a sectional view taken along the arrow A in FIG. 1, and FIG. 2B is a sectional view taken along line BB in FIG. In the drawing, reference numeral 25 denotes a pulley. The pulley 25 is provided on the opposite side of the grinding wheel 10 via the motor 5, and the central portion of the inner surface is coupled to the rotating shaft 6 of the motor 5, and the outer surface Protrusions 26 are provided at the peripheral edge of each.
[0022]
As shown in FIG. 1, a pulley cover 27 that is a non-rotating member that covers the pulley 25 is provided around the pulley 25. A lower end of the pulley cover 27 is fixed on the base 4, and a proximity sensor 28 is provided on the upper portion so as to face the passing position of the protruding portion 26. The proximity sensor 28 is electrically connected to the control unit 40, and outputs an ON signal when the projection 26 moves in conjunction with the rotation of the pulley 25, and outputs an OFF signal when separated.
[0023]
The control panel 3 has a control unit 40 that controls the operation of the grinding machine 1 configured by a sequence circuit in the panel, and the control unit 40 controls the locking and unlocking of the cylinder lock 20. As a function. In addition to the rotation start button 31, rotation stop button 32, and emergency stop button 33 for grinding operation, a lock operation button 34 for locking the cylinder lock 20 and a lock release button for unlocking are also provided on the control panel 3. 35. An operation valid lamp 36 is provided for displaying whether or not the operation of the lock operation button 34 and the lock release button 35 is in a valid state.
[0024]
FIG. 3 is a block diagram illustrating input / output of the control unit 40. The control unit 40 includes a monitoring timer 41 and a rotation stop determination processing means 42 as internal mechanisms. On the input side, the safety plug 18, the proximity sensor 28, the rotation start button 31, the rotation stop button 32, and the emergency stop button 33 are provided. The lock operation button 34 and the lock release button 35 are connected, and the output side is connected to the motor 5, the actuator coupled to the attachment 7, the cylinder lock 20, and the operation valid lamp 36.
[0025]
Based on signals input from the proximity sensor 28 and various operation buttons, the control unit 40 performs various control processes such as power supply to the motor 5, operation of the actuator 8 and the cylinder lock 20, and lighting of the operation valid lamp 36. .
[0026]
The maintenance work for exchanging the grinding wheel 10 of the grinding machine 2 having the above configuration is performed according to the flow shown in FIG.
[0027]
First, when the rotation stop button 32 is operated in the grinding operation state (step S1), a rotation stop command is input to the control unit 40, the power supply to the motor 5 is stopped, and at the same time, the rotation stop determination processing means 42 will be described later. A rotation stop determination process is performed.
[0028]
If it is determined by this determination processing that the rotation of the grinding wheel 10 has not stopped, the operation enable lamp 36 of the control panel 3 remains off and the operation of the lock operation button 34 and the lock release button 35 is invalid. A certain state is maintained, and even if these operation buttons are operated, all are canceled. Therefore, the door 16 is kept locked by the cylinder lock 20 and cannot be opened.
[0029]
On the other hand, when it is determined that the rotation of the grinding wheel 10 has completely stopped, the operation of the lock operation button 34 and the lock release button 35 is enabled, and the operation enable lamp 36 on the panel is lit. After confirming that the operation valid lamp 36 is lit (step S2), when the lock release button 35 is operated (step S3), a control signal is sent from the control unit 40 to the cylinder lock 20, the rod 22 is retracted and the open / close door 16 is unlocked. Locked. Then, the safety door 18 is removed and the door 16 is opened (step S4), and the grinding wheel 10 is replaced (step S5).
[0030]
After the grinding wheel 10 is replaced, the door 16 is closed (step S6), and the safety plug 18 is inserted and held in the socket, and then the lock operation button 34 is turned on (step S7). The output of the control signal is interrupted, the rod 22 of the cylinder lock 20 protrudes by the biasing force of a spring (not shown) provided in the cylinder body 21, and the opening / closing door 16 is locked by the cylinder lock 20.
[0031]
When the rotation start button 31 is operated with the door 16 being locked, power is supplied to the motor 5 and the grinding wheel 10 is rotated (step S8). When the rotation stop determination processing means 42 determines that the grinding wheel 10 is rotating, the operation valid lamp 36 is turned off again, and the operations of the lock operation button 34 and the lock release button 35 are all invalidated.
[0032]
Next, determination processing performed by the rotation stop determination processing means 42 will be described below. FIG. 5 is a flowchart for explaining the rotation stop determination process, and FIG. 6 is a time chart showing the output signal of the proximity sensor 28. First, in step S11, it is determined whether or not the rotation stop button 32 has been operated. If the rotation stop button 32 is operated (YES), the rotation of the grinding wheel 10 is performed after the rotation stop button 32 is operated. The process proceeds to step S12 in order to determine whether or not a first set time t ₁ set in advance as a time required until the stop has elapsed.
[0033]
In step S12, the elapsed time t after the operation of the rotation stop button 32 exceeds the first set time t ₁ (for example, 30 seconds) based on the time measured by the monitoring timer 41 provided in the control unit 40 (t _It is determined whether ₁ <t). Then, the elapsed time t until passage of t ₁ first set time (NO), without going to the next step, after the lapse (YES), whether the rotation of the grinding wheel 10 is completely stopped The process proceeds to step S13 for determination.
[0034]
In step S13, whether or not the output signal from the proximity sensor 28 has been kept in the ON state or the OFF state for the second set time t ₂ (for example, 10 seconds) after the first set time t _{1 has} elapsed. Is judged. Here, when it is determined that no continued (NO), i.e. if both of the ON and OFF is input during a second set time t _2, and determines that the grinding wheel 10 is still rotating, Continue monitoring without going to the next step.
[0035]
If the output state of either ON or OFF is continued for the second set time t ₂ (YES), it is determined that the rotation of the grinding wheel 10 has completely stopped, and the process proceeds to step S14. 6A shows a case where the rotation of the protrusion 26 stops at a position where OFF is output, and FIG. 6B shows a case where the rotation of the protrusion 26 stops at a position where it outputs ON.
[0036]
In step S14, processing for making the operation of the cylinder lock 20 effective is performed. Here, the operation of the lock operation button 34 and the lock release button 35 is validated, and the operation valid lamp 36 is turned on. Accordingly, only when the rotation of the grinding wheel 10 is completely stopped, the opening / closing door 16 can be unlocked and opened, and maintenance work and the like in the case 12 can be performed via the opening 15.
[0037]
According to the grinding machine 1 described above, the rotation of the grinding wheel 10 is monitored by the proximity sensor 28, and the opening / closing door 16 is locked by the cylinder lock 20 while the grinding wheel 10 is rotating. Prepared opening is prevented.
[0038]
Therefore, even when the power supply to the motor 5 is stopped and the grinding wheel 10 is inertially rotated by inertia, the opening / closing door 16 can be prevented from being opened, and the maintenance work in the case 12 is performed. The safety of the person can be ensured.
[0039]
Further, when the operating power is cut off during operation control, for example, when an emergency stop button 33 provided on the surface of the control panel 3 is pressed, when the safety plug 18 is removed from the socket during grinding operation, In such a case, since the locked state by the cylinder lock 20 is maintained, the opening / closing door 16 can be prevented from being opened, and when the operation power is input again, the rotation stop determination processing means 42 monitors the rotation of the grinding wheel. Is done. Therefore, when the grinding stone 10 is inertially rotated in the case 12, the opening / closing door 16 can be prevented from being opened, and the operator's safety can be ensured.
[0040]
Further, in the rotation stop determination processing means 42, after the first set time t ₁ has elapsed from the operation of the rotation stop button 32, the output state of either the ON signal or the OFF signal from the proximity sensor 28 is changed to the second set time t. _{Since the} unlocking operation is effective when it continues for _two , the rotation state of the grinding wheel can be reliably monitored.
[0041]
In addition, simple components such as the cylinder lock 20 and proximity sensor 28 can be attached to the existing grinding machine 1 and the sequence circuit in the control panel 3 can be easily configured with a slight modification, so it is provided at low cost. can do.
[0042]
In the above-described embodiment, the proximity sensor 28 is used as means for detecting the rotation of the grinding wheel 10, but the present invention is not limited to this. For example, another non-contact sensor such as a photoelectric sensor is used. In addition, the locking means can be variously modified without departing from the gist of the present invention.
[0043]
【The invention's effect】
As described above, according to the safety device for a grinder according to the present invention, after the grinder stop operation is performed, a time required until the rotation of the grinding wheel is stopped by the first set time is given, Thereafter, the signal state from the rotation detecting means is monitored, and the unlocking operation of the locking means for locking the open / close door is validated when the same signal state from the rotation detecting means continues for a preset second set time. The That is, it is estimated that the rotation of the grinding wheel is stopped according to the first set time, and thereafter, the signal state from the rotation detecting means that repeatedly outputs different signals in synchronization with the rotation of the grinding wheel is monitored. If the signal from the rotation detecting means continues in the same signal state for the set time, it can be verified that the grinding wheel has stopped reliably. Therefore, the open / close door can be opened only after the rotation of the grinding wheel has been reliably stopped, and the safety of the operator who performs maintenance work or work replacement from the opening can be ensured more reliably.
Further, the rotation detection is performed after the first set time has elapsed since the grinder stop operation has been performed and the grinding wheel has been considered to have stopped rotating, that is, the grinding wheel has stopped or has been rotated at a low speed. Since the signal state from the means is monitored, when the signal state from the rotation detecting means is monitored, the processing can be simplified and realized at low cost.
[Brief description of the drawings]
FIG. 1 is a front view of a grinding machine in the present embodiment.
FIG. 2 is an explanatory diagram of rotation detection means.
FIG. 3 is a block diagram illustrating input / output to / from a control unit.
FIG. 4 is a flowchart for explaining maintenance work for exchanging a grinding wheel.
FIG. 5 is a flowchart illustrating rotation stop determination processing.
FIG. 6 is a time chart showing an output signal of a proximity sensor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Grinding machine 3 Control board 10 Grinding wheel 12 Case 16 Opening / closing door 20 Cylinder lock (locking means; actuator)
26 Protrusion (rotation detection means)
28 Proximity sensor (rotation detection means)
40 Control unit (locking control means)

Claims (4)

In a safety device for a grinding machine in which a grinding wheel is rotationally driven in a case having an open / close door
Rotation detection means for repeatedly outputting different signals in synchronization with rotation of the grinding wheel;
Locking means for locking the door;
After the elapse of a first setting time set in advance as a time required from the grinding machine stop operation to the rotation of the grinding wheel, the same signal state from the rotation detecting means continues for a second setting time set in advance. Locking control means for enabling the unlocking operation of the locking means,
Safety device grinding machine characterized by comprising a. The rotation detection means repeatedly outputs ON / OFF in synchronization with the rotation of the grinding wheel,
The locking control means is either ON or OFF from the rotation detecting means after the elapse of a first set time which is preset as a time required from the stop operation of the grinding machine until the rotation of the grinding wheel stops. The safety device for a grinding machine according to claim 1, wherein the unlocking operation is validated when one state continues for a preset second set time . The rotation detecting means includes
A protrusion that rotates in conjunction with the grinding wheel;
The safety device for a grinding machine according to claim 1 or 2, wherein the safety device is a proximity sensor that is fixed to a non-rotating member and switches on and off by the approach and separation of the protrusion . The locking control means outputs the unlocking signal to the locking means only when the grindstone complete stop state is detected and there is a request for unlocking,
The locking means is composed of a rod protruding type actuator at all times, and only when an unlocking signal is output from the locking control means, the rod can be retracted to open the door . The safety device for a grinding machine according to any one of 3 above.

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