Clamping device of edge grinding machine

Abstract

A clamping device of an edge grinding machine comprises a control panel, a machine head and a clamping shaft, the machine head is connected with a mirror shaft, and the mirror shaft is connected with a lens; the clamping shaft is connected with the clamping screw rod, the clamping screw rod is sleeved with the clamping nut, the clamping force backpressure reed is arranged on the clamping screw rod on the rear side of the clamping nut and connected with the lever rotating shaft, the lever rotating shaft is connected with the thrust spring, and the thrust spring is connected with the clamping nut. The clamping nut is connected with the clamping force backpressure reed, the thrust spring is connected with the clamping force amplification lever, the clamping force amplification lever is connected with the push rod, and the strain gauge is arranged on the front side of the push rod. When the clamping force on the lens starts to be gradually increased, the generated counter-acting force acts on the strain gauge through the clamping nut, the clamping force backpressure reed and the clamping force amplification lever; the deformation quantity generated by the strain gauge is collected and processed by the control panel and then is fed back to the clamping motor to control the clamping motor to operate, so that the clamping force on the lens is kept constant.

Description

Technical Field

[0001] The utility model relates to the technical field of edge grinders, in particular to a clamping device for an edge grinder. Background Art

[0002] During the grinding process, the clamping force for clamping the lens to be ground needs to be kept constant. If the clamping force is too low, the lens will not be clamped tightly and will run off the axis. If the clamping force is too high, the lens will be crushed.

[0003] Currently, all edge grinders on the market adopt a current sampling scheme to detect whether the clamping force on the lens to be ground reaches the expected value, and the clamping motor control scheme used is logic high and low level control, that is, the clamping motor runs at the maximum speed. This will cause that even when the chip detects that the expected clamping force has been reached and controls the clamping motor to stop, the clamping motor still continues to clamp the lens under the action of inertia, resulting in too large a clamping force and the lens being crushed.

[0004] During the grinding process, due to the stress release of the rubber chuck and overcoming the reaction force of the grinding force during grinding, etc., the clamping force on the lens will decrease, resulting in the situation that the lens is not clamped tightly and runs off the axis.

[0005] During the grinding process, at this time, the clamping motor is in a stalled state. It is no longer realistic to detect the clamping force by detecting the current. Only the clamping force can be increased at the beginning of clamping. Therefore, all edge grinders on the market have a problem that brittle lenses will be crushed and thick lenses will run off the axis. Summary of the Utility Model

[0006] The purpose of the utility model is to overcome the deficiencies existing in the prior art and provide a clamping device for an edge grinder.

[0007] The purpose of the utility model is achieved by the following technical solutions: A clamping device for an edge grinder, including a control board, a machine head and a clamping shaft. The machine head is connected to a lens shaft, and the lens shaft is connected to a lens. The clamping shaft is connected to a clamping screw. A clamping nut and a clamping force back-pressure spring piece are sleeved on the clamping screw. The clamping nut is on the left side of the clamping force back-pressure spring piece. A clamping force amplification lever is arranged on the right side of the clamping force back-pressure spring piece. The clamping force amplification lever is connected to a thrust spring. The clamping force amplification lever is connected to a lever rotation shaft. The clamping force amplification lever is connected to a push rod. A strain gauge is arranged on the left side of the push rod.

[0008] Further, a rubber chuck is arranged on the clamping shaft.

[0009] Further, the clamping nut is connected to a clamping motor.

[0010] Further, a plastic suction cup is arranged on the lens shaft.

[0011] Furthermore, the push rod, the clamping force amplification lever, the thrust spring, the lever rotation shaft, and the clamping force back pressure spring piece form a force-consuming lever structure. When the clamping force back pressure spring piece moves a small distance, under the action of the force-consuming lever, the push rod can move a large distance.

[0012] Furthermore, the strain gauge is fixed on the steel sheet. One end of the steel sheet is fixed to the machine head, and the other end of the steel sheet is free. The height of the steel sheet is flush with the push rod. When the push rod moves, it pushes the steel sheet to deform, thereby causing the resistance value of the strain gauge to change.

[0013] The utility model has the following beneficial effects compared with the prior art:

[0014] In the utility model, through the screw drive of the clamping screw in the clamping nut, an axial movement is performed to push the clamping axial lens closer. When the clamping shaft contacts the lens and continues to move forward, the clamping force on the lens begins to gradually increase. At the same time, the generated reaction force acts on the strain gauge through the clamping nut, the clamping force back pressure spring piece, and the clamping force amplification lever. The deformation amount generated by the strain gauge is collected and processed by the control board, and then fed back to the clamping motor to control the operation of the clamping motor, so that the clamping force on the lens remains constant. Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of the clamping device of the edging machine of the utility model;

[0016] Figure 2 It is a schematic diagram of the module connection of the clamping force control system of the edging machine of the utility model;

[0017] Figure 3 It is a schematic diagram of the cascade PID algorithm of the clamping force control system of the edging machine of the utility model. Detailed Embodiment

[0018] The following further describes the utility model with reference to the drawings and embodiments.

[0019] As Figures 1-3 shown, an edging machine clamping device includes a control board 13, a machine head 1, and a clamping shaft 4. The machine head 1 is connected to a lens shaft 2, and the lens shaft 2 is connected to a lens 3. The clamping shaft 4 is connected to a clamping screw 12. A clamping nut 5 and a clamping force back pressure spring piece 11 are sleeved on the clamping screw 12. The clamping nut 5 is on the left side of the clamping force back pressure spring piece 11, and a clamping force amplification lever 8 is on the right side of the clamping force back pressure spring piece 11. The clamping force amplification lever 8 is connected to a thrust spring 9, a lever rotation shaft 10 is connected to the clamping force amplification lever 8, the clamping force amplification lever 8 is connected to a push rod 7, and a strain gauge 6 is arranged on the left side of the push rod 7.

[0020] The machine head 1 is a component of the edging machine, and the clamping force control system of the edging machine operates on the machine head 1. The mirror axis 2 cannot move axially and is the force application point of the lens 3. The lens 3 is the lens to be processed and can be replaced with different lenses according to customer requirements. The clamping shaft 4 and the clamping screw 12 are fixed together by a hard connection method. The clamping motor drives the clamping nut 5 to rotate radially through a belt. Under the screw drive of the clamping nut 5, the clamping screw 12 moves axially, and the clamping shaft 4 approaches the lens 3. To prevent the lens 3 from being directly and hard contacted by the clamping shaft 4, resulting in scratches or crushing, a rubber chuck is installed at the contact point between the clamping shaft 4 and the lens 3 to play a buffering role. When the rubber chuck contacts the lens 3 and continues to move forward, the clamping force on the lens 3 begins to gradually increase. At the same time, the reaction force generated by the lens 3 acts on the strain gauge 6 through the clamping nut 5, the clamping force back pressure spring piece 11, and the clamping force amplification lever 8, causing the strain gauge 6 to deform. The deformation generated by the strain gauge 6 is collected by the control board 13. After being calculated by the internal cascade PID algorithm of the control board 13, the clamping motor is controlled to operate, so that the clamping force on the lens 3 remains constant.

[0021] The machine head 1 is a component of the edging machine and is mainly used to clamp the lens to be ground. The machine head 1 is equivalent to a platform, and the clamping force control system of the edging machine operates entirely on the machine head 1.

[0022] A plastic suction cup is placed between the mirror axis 2 and the lens 3 to prevent the lens from being scratched or crushed and at the same time facilitate the customer to take out the ground lens. The lens 3 can be made of various materials, such as PC, resin, glass, etc. Since the clamping force required for grinding lenses of various materials is different, the clamping force of the clamping force control system of the edging machine is adjustable. To prevent the lens from being scratched or crushed, a rubber chuck is placed between the lens 3 and the clamping shaft 4, and the rubber chuck is fixed on the clamping shaft 4.

[0023] The clamping nut 5 can move radially under the drive of the clamping motor. At the same time, since there is a gap around the clamping nut 5, under the reaction force of the lens 3, the clamping nut 5 can be pushed to move towards the clamping force back pressure spring piece 11, and the movement distance is linearly related to the clamping force on the lens 3. The push rod 7, the clamping force amplification lever 8, the thrust spring 9, the lever rotation shaft 10, and the clamping force back pressure spring piece 11 form a force-consuming lever structure. When the clamping force back pressure spring piece 11 moves a small distance, the push rod 7 can also move a large distance under the action of the force-consuming lever.

[0024] The strain gauge 6 is fixed to the steel sheet with Kraft glue. One end of the steel sheet is fixed on the machine head and the other end is free, and the height is flush with the push rod 7. When the push rod 7 moves, it pushes the steel sheet to deform, resulting in a change in the resistance value of the strain gauge 6.

[0025] Please refer to Figure 2 , for a clamping force control system of an edging machine based on a cascade PID algorithm in the present utility model. The control board 13 is composed of a voltage stabilization module 131, a display module 132, a current detection module 133, a microcontroller module 134, a key input module 135, a motor drive module 136, and a strain gauge sensor 137. The voltage stabilization module 131 is respectively connected to the display module 132 and the microcontroller module 134. The current detection module 133 is respectively connected to the motor drive module 136 and the microcontroller module 134. The microcontroller module 134 is respectively connected to the motor drive module 136, the strain gauge sensor 137, the key input module 135, and the display module 132

[0026] The control board 13 is powered by 24V DC power supply. The 24V DC power supply is stepped down to 5V DC power supply by the first-stage voltage stabilization circuit of the voltage stabilization module 131 to supply power to the display module 132. The 5V DC power supply is stepped down to 3.3V DC power supply by the second-stage voltage stabilization circuit of the voltage stabilization module 131 to supply power to the microcontroller module 134, the key input module 135, and the strain gauge sensor 137 respectively

[0027] When the system is powered on, the user inputs the required clamping force through the key input module 135. The microcontroller module 134 displays this clamping force on the display module 132, and compares it with the set clamping force by collecting the data of the strain gauge sensor 137. The motor drive module 136 is controlled by PWM to adjust the motor speed to achieve the same as the set clamping force. The current detection module 133 is used to monitor whether the motor is operating abnormally. If abnormal, the user will be informed of the motor module abnormality through the display module 132

[0028] The voltage stabilization module 131 is composed of two-stage voltage stabilization circuits. The voltage stabilization chip of the first-stage voltage stabilization circuit is LM2596R-5.0, and the voltage stabilization chip of the second-stage voltage stabilization circuit is AZ1117CR-3.3TRG1. The current detection module 133 is a high-side current detection, which can well monitor whether the motor has abnormal conditions. The current detection chip is INA139NA / 3K. The strain gauge sensor (137) collects the resistance value of the strain gauge 6 and converts it into a digital quantity and transmits it to the microcontroller module 134

[0029] Please refer to Figure 3 , for a schematic diagram of the cascade PID algorithm of the present utility model. The algorithm adopted inside the microcontroller module 134 is the cascade PID algorithm, which can make the system reach the desired clamping force more quickly and stably

[0030] After the user sets the desired clamping force, the microcontroller module 134 first collects the current resistance value of the strain gauge 6, converts the current resistance value into the current clamping force, and then enters the position-loop PID calculation with the desired clamping force to output the desired speed, i.e., the desired moving speed of the clamping shaft 4. According to the resistance values of the strain gauge 6 at the previous moment and the current moment, the resistance change rate of the strain gauge 6 is calculated, and from the resistance change rate, the current rotational speed of the motor, i.e., the current moving speed of the clamping shaft 4, can be obtained. The desired motor rotational speed and the current motor rotational speed are brought into the speed-loop PID control together to output a PWM control waveform. By adjusting the duty cycle, the rotational speed of the clamping motor is changed, i.e., the current clamping force is changed. When external influences are input, such as the stress release of the rubber chuck and the grinding force during grinding, through the above cascade PID algorithm control, the clamping force on the lens 3 can still be quickly kept constant.

[0031] Although the present utility model has been disclosed above with preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present utility model. Therefore, the protection scope of the present utility model shall be defined by the claims.

Claims

1. An edge grinding machine clamping device, characterized in that, It includes a control board (13), a machine head (1) and a clamping shaft (4). The machine head (1) is connected to a lens shaft (2), and the lens shaft (2) is connected to a lens (3). The clamping shaft (4) is connected to a clamping screw (12). A clamping nut (5) and a clamping force back-pressure spring piece (11) are sleeved on the clamping screw (12). The clamping nut (5) is on the left side of the clamping force back-pressure spring piece (11). A clamping force amplification lever (8) is arranged on the right side of the clamping force back-pressure spring piece (11). The clamping force amplification lever (8) is connected to a thrust spring (9). The clamping force amplification lever (8) is connected to a lever rotation shaft (10). The clamping force amplification lever (8) is connected to a push rod (7). A strain gauge (6) is arranged on the left side of the push rod (7).

2. The edge grinding machine clamping device according to claim 1, characterized in that: A rubber chuck is arranged on the clamping shaft (4).

3. The edge grinding machine clamping device according to claim 2, characterized in that: The clamping nut (5) is connected to a clamping motor.

4. The edge grinding machine clamping device according to claim 3, characterized in that: A plastic suction cup is arranged on the lens shaft (2).

5. The edge grinding machine clamping device according to claim 4, characterized in that: The push rod (7), the clamping force amplification lever (8), the thrust spring (9), the lever rotation shaft (10) and the clamping force back-pressure spring piece (11) form a force-consuming lever structure. When the clamping force back-pressure spring piece (11) moves a small distance, under the action of the force-consuming lever, the push rod (7) can move a large distance.

6. The edge grinding machine clamping device according to claim 5, wherein: The strain gauge (6) is fixed on a steel sheet. One end of the steel sheet is fixed on the machine head (1), and the other end of the steel sheet is free. The height of the steel sheet is flush with the push rod (7). When the push rod (7) moves, it pushes the steel sheet to deform, thereby causing the resistance value of the strain gauge (6) to change.

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