Negative pressure flexible clamp and method for detecting whether an object is clamped

Abstract

The present invention discloses a negative pressure flexible clamp and a method for detecting whether an object is clamped, the negative pressure flexible clamp comprises a mounting seat and a flexible clamping claw, the flexible clamping claw comprises a clamping part and a connecting part made of elastic material, the clamping part comprises at least two fingers that cooperate with each other for clamping, the connecting part comprises a driving chamber, the connecting part is provided with a communicating port, an air inlet and exhaust joint is installed on the mounting seat, a detection device for detecting whether the fingers clamp an object is installed on the flexible clamping claw or on the flexible clamping claw and the mounting seat, the detection device is used to detect the bending deformation amplitude of the finger, or detect the force condition of the fingertips of the finger, or detect the deformation amplitude of the driving chamber. The method uses the above-mentioned negative pressure flexible clamp to accurately detect whether the flexible clamp clamps the object, thereby ensuring the accuracy of the clamping action of the negative pressure flexible clamp.

Description

Technical Field

[0001] The present invention relates to a negative pressure flexible clamp, and in particular to a clamping method for detecting whether the negative pressure flexible clamp is clamping an object. Background Art

[0002] In industrial automation, gripping at the end of a robotic arm is primarily accomplished by rigid grippers or vacuum suction cups. However, rigid grippers struggle to control force, making it difficult to non-destructively grasp soft and fragile objects. Vacuum suction cups also struggle to adapt to irregularly shaped objects with rough surfaces and openings during handling. This limits the application scenarios of both. Flexible grippers, made of elastic materials, can grasp soft and fragile objects without damaging them. On August 18, 2017, the applicant applied for a utility model patent with patent number CN201721042513.4, entitled A New Flexible Clamp, Flexible Clamp and Flexible Clamping Pen. The patent describes a flexible clamp comprising a clamping portion and a connecting portion made of elastic material, the clamping portion comprising at least two fingertips that cooperate with each other for clamping, a finger gap being formed between the fingertips, a finger cavity being provided inside each fingertip, the connecting portion comprising a connecting chamber that is connected to each finger cavity, a connecting port being provided on the connecting portion that communicates with the connecting chamber, the fingertip comprising an inner wall close to the finger gap and an outer wall away from the finger gap, the thickness of the inner wall being smaller than the thickness of the outer wall or the elastic modulus of the inner wall being smaller than the elastic modulus of the outer wall. The flexible gripper of this structure is suitable for clamping small objects. During the operation of the flexible gripper, the fingertips are opened by positive pressure driving. When the air is exhausted, the driving medium in the finger cavity and the connecting cavity is extracted from the connecting port. Similarly, the bending deformation of the inner wall is greater than the deformation of the outer wall, thereby achieving the closure of the fingertips. In this way, the flexible gripper can complete the clamping of small objects without damaging the surface of the object. However, this flexible gripper cannot clamp some larger objects. Of course, the size of the flexible gripper can be increased. However, since the size of the flexible gripper increases, the length of the fingertips will also increase, and the clamping area between the fingertips will also increase. Therefore, the clamping force of the fingertips is relatively small when the negative pressure is used. Since the chuck is made of elastic material, the strength of the chuck itself is not high, which limits the clamping force of the chuck. Therefore, even if the size of the flexible gripper in the background art is increased, it is not suitable for clamping large objects. In addition, during the use of flexible clamps, whether the flexible clamps can clamp objects has always been a technical difficulty. Different from traditional metal mechanical clamps, traditional mechanical clamps generally include a mounting plate and a clamp hinged on the mounting plate. The clamp is driven by a clamp power device. Generally, this type of mechanical clamp is easy to detect whether it is clamping an object. The conventional practice is to install a detection sensor that directly detects the clamped object on the mounting plate, such as a reflective photoelectric detection sensor. When the clamp holds an object, the light signal of the photoelectric sensor will be reflected, thereby judging that the mechanical clamp has clamped the object. Since the clamp and the mounting plate are both in an open state, the fixing of the photoelectric detection sensor is very convenient.However, since the clamping part and the connecting part of the negative pressure flexible clamp are both in a closed state, the fingertips are located below the connecting part, and a driving chamber for convenient vacuum extraction is formed in the connecting part. The upper end of this flexible clamp is directly connected to the air inlet nozzle and directly fixed to the mounting plate through the air inlet nozzle. The flexible clamp is located below the mounting plate, so there is no installation position for the detection sensor. At the same time, the flexible clamp itself is made of flexible material and is easy to deform. Therefore, it is a technical difficulty for the flexible clamp to determine whether it has clamped an object. Summary of the Invention

[0003] The first technical problem to be solved by the present invention is to provide a negative pressure flexible clamp that can accurately detect whether the flexible clamp is clamping an object, thereby ensuring the accuracy of the clamping action of the negative pressure flexible clamp.

[0004] The second technical problem to be solved by the present invention is to provide a method for detecting whether a negative pressure flexible clamp is clamping an object. The method uses the above-mentioned negative pressure flexible clamp and can accurately detect whether the flexible clamp is clamping an object.

[0005] In order to solve the first technical problem mentioned above, the technical solution of the present invention is: a negative pressure flexible clamp, comprising a mounting seat and a flexible clamp fixed on the mounting seat, the flexible clamp comprising a clamping part and a connecting part made of elastic material, the clamping part comprising at least two fingers that cooperate with each other for clamping, the connecting part comprising a driving chamber, the connecting part is provided with a connecting port communicating with the driving chamber, an air inlet and exhaust joint connected to the connecting port is installed on the mounting seat, a detection device for detecting whether the finger is clamping an object is installed on the flexible clamp or on the flexible clamp and the mounting seat, the detection device is used to detect the bending deformation amplitude of the finger, or detect the force condition of the fingertip of the finger, or detect the deformation amplitude of the driving chamber.

[0006] As a preferred solution, the detection device includes a detected piece fixedly mounted on the outside of the finger, the detected piece deflects as the finger bends, and a deflection detection sensor for detecting the deflection device of the detected piece is provided on the mounting seat.

[0007] As a preferred solution, one end of the detected piece is fixed on a connecting seat, and the connecting seat is bonded to the outside of the finger or fixed on the finger by clamping.

[0008] As a preferred solution, the detection device includes a deformation signal detection switch, and the deformation signal detection switch includes a fixed pole piece and an elastic pole piece fixed on the connecting part and located in the driving chamber, a gap is provided between the fixed pole piece and the elastic pole piece, the positions of the fixed pole piece and the elastic pole piece are on the deformation path of the chamber wall of the driving chamber, and the connecting part is provided with a first pin respectively connected to the fixed pole piece and the elastic pole piece.

[0009] As a preferred solution, the detection device includes a pressure signal detection switch, the pressure signal detection switch includes a first pressure detection electrode and a second pressure detection electrode, the finger portion is provided with a mounting groove on the clamping portion for clamping an object, the first pressure detection electrode and the second pressure detection electrode are installed in the mounting groove, a gap is provided between the first pressure detection electrode and the second pressure detection electrode, and the finger portion is provided with a second pin connected to the first pressure detection electrode and the second pressure detection electrode respectively.

[0010] As a preferred solution, the driving chamber includes a cavity bottom wall and a cavity side wall, the cavity bottom wall is located between the fingers and arches toward the fingertips, the cavity side wall is connected to the heel of each finger, the thickness of the cavity bottom wall is smaller than the thickness of the cavity side wall or the elastic modulus of the cavity bottom wall is smaller than the elastic modulus of the cavity side wall, and a tension reinforcement block for enhancing the pulling force is connected between the side wall of each finger and the cavity bottom wall.

[0011] As a preferred solution, the connecting part also includes a cavity top wall, the connecting port is arranged on the cavity top wall, and the cavity top wall or the cavity bottom wall is provided with an anti-blocking structure to prevent the deformed cavity bottom wall from blocking the connecting port, and the anti-blocking structure is located in the driving chamber.

[0012] As a preferred solution, the drive chamber is also provided with an extension chamber extending toward the heel of each finger, and a transition surface is provided on the outer side of the cavity side wall in the area adjacent to the heel, and the lower end of the transition surface is closer to the center of the flexible clamp than the upper end.

[0013] As a preferred solution, a reinforcement portion is provided at the upper end of the cavity side wall, and the reinforcement portion extends toward the center to form a gathered shape. The upper end of the cavity side wall is bonded to or integrally formed with the cavity top wall, and the lower part of the reinforcement portion is also provided with a functional surface for changing the direction of pressure so that the pressure is directed obliquely upward.

[0014] After adopting the above technical scheme, the effect of the present invention is: due to a negative pressure flexible clamp, including a mounting seat and a flexible clamping claw fixed on the mounting seat, the flexible clamping claw includes a clamping part and a connecting part made of elastic material, the clamping part includes at least two fingers that cooperate with each other for clamping, the connecting part includes a driving chamber, and a connecting port that communicates with the driving chamber is provided on the connecting part, and an air inlet and exhaust joint connected to the connecting port is installed on the mounting seat, and a detection device for detecting whether the finger is clamping an object is installed on the flexible clamping claw or on the flexible clamping claw and the mounting seat, and the detection device is used to detect the bending deformation amplitude of the finger, or detect the force condition of the fingertip of the finger, or detect the deformation amplitude of the driving chamber. Therefore, by detecting the bending deformation amplitude of the finger or the force condition of the finger or detecting the deformation amplitude of the driving chamber by the detection device, it can be determined whether the flexible clamp is normally clamping an object or not. When the object is not clamped, the detection device will detect the bending amplitude of the finger. When the object is not clamped, the bending amplitude of the finger will be larger, thereby judging whether the object is clamped in turn; and the detection device can also detect the force on the fingertips of the finger. When the flexible clamp clamps the object, the fingertips of the flexible fingers will be subjected to squeezing force. By detecting the force on the fingertips, it is possible to accurately judge whether the flexible clamp has clamped the object; of course, the detection device can also detect the deformation amplitude of the drive chamber to judge whether the object is clamped. When the finger does not clamp the object, the bending deformation of the finger will be larger. Correspondingly, the deformation amplitude of the drive chamber is larger than the deformation amplitude when clamping the object, which can also detect whether the flexible clamp has clamped the object. From the above, it can be seen that the negative pressure flexible clamp does not detect the clamped object, but directly detects the state change of the flexible clamp, which can also accurately detect whether the object is clamped and ensure the clamping accuracy of the flexible clamp.

[0015] Furthermore, since the detection device includes a detected piece fixedly mounted on the outside of the finger, the detected piece deflects as the finger bends, and a deflection detection sensor for detecting the deflection device of the detected piece is provided on the mounting seat, when the flexible clamp is clamped, the finger bends, which drives the detected piece to deflect. Since the positions of the fingers of the flexible clamp when clamping an object and not clamping an object are different, the deflection position of the detected piece can be detected by the deflection detection sensor at this time to accurately determine whether the flexible clamp has clamped the object.

[0016] Since one end of the detected piece is fixed to the connecting seat, and the connecting seat is bonded to the outside of the finger or fixed to the finger by clamping, the detected piece can be better fixed to the finger without hindering the bending of the finger.

[0017] Furthermore, since the detection device includes a deformation signal detection switch, the deformation signal detection switch includes a fixed electrode and an elastic electrode fixed on the connecting portion and located in the driving chamber, a gap is provided between the fixed electrode and the elastic electrode, the positions of the fixed electrode and the elastic electrode are on the deformation path of the chamber wall of the driving chamber, and the connecting portion is provided with a first pin connected to the fixed electrode and the elastic electrode respectively. After the signal detection switch is electrically connected to the control system of the flexible clamp, during the clamping process of the flexible clamp, the chamber wall of the driving chamber will deform, and the fixed electrode and the elastic electrode are on the deformation path, then if no object is clamped, the deformation of the driving chamber will be greater, so that the chamber wall of the driving chamber will touch the elastic electrode, so that the deformation of the elastic electrode contacts the fixed electrode and generates a signal change, so that it can accurately detect whether the flexible finger has clamped an object. The detection result of the detection device is accurate, and the deformation signal detection switch can be set when the flexible clamp is formed. When in use, it is only necessary to connect the first pin to the external control system, which is convenient to use.

[0018] Alternatively, the detection device includes a deformation signal detection switch, which includes a detected rod fixed on the bottom wall of the driving chamber, and the upper end of the detected rod is provided with a detected part 2 made of magnetic material or metal material, the detected rod extends into the air inlet and exhaust joint and cooperates with the guide of the inner hole of the air inlet and exhaust joint, and the mounting seat or the air inlet and exhaust joint is provided with a magnetic detection sensor 2 or a metal detection sensor 2 for detecting the detected part 2, and a flow channel for facilitating gas flow is provided on the detected rod or between the detected rod and the air inlet and exhaust joint, so when using this structure, gas is extracted from the air inlet and exhaust joint. The air causes the flexible clamp to generate negative pressure, and at this time the bottom wall of the driving chamber will be deformed upward. At this time, the detected rod will also move upward. Therefore, when the flexible clamp clamps an object, the detected part 2 is just detected by the magnetic detection sensor 2 or the metal detection sensor 2, and the flexible clamp fails to clamp the object or the clamped object falls. At this time, the deformation of the bottom wall of the cavity will increase, and the detected part 2 will be out of the detection range of the magnetic detection sensor 2 or the metal detection sensor 2, so that the detection signal changes. Through the above-mentioned detection principle, it is possible to accurately detect whether an object is clamped, and the setting of the flow channel can facilitate the smooth passage of gas.

[0019] Furthermore, since the detection device includes a pressure signal detection switch, the pressure signal detection switch includes a first pressure detection electrode and a second pressure detection electrode, the finger portion is provided with a mounting groove on the clamping portion for clamping an object, the first pressure detection electrode and the second pressure detection electrode are installed in the mounting groove, and a gap is provided between the first pressure detection electrode and the second pressure detection electrode, the finger portion is provided with a second pin connected to the first pressure detection electrode and the second pressure detection electrode respectively, or the pressure signal detection switch includes a detected part made of magnetic material or metal material, a deformation groove for facilitating deformation of the fingertip is provided on the fingertip of the finger portion, the detected part is fixed on the inner wall of the deformation groove, and the outer wall of the deformation groove is provided with a magnetic detection sensor or a metal detection sensor for detecting the detected part. Therefore, when the flexible clamp clamps an object, the clamping part of the finger will be subjected to an extrusion force, and the extrusion force will force the first pressure detection electrode and the second pressure detection electrode to move closer to each other to produce a signal change, or when the flexible clamp clamps the object, due to the presence of the deformation groove, the fingertip will deform itself, so that the detected part will move closer to the magnetic detection sensor or the metal detection sensor, so that it can be detected and produce a signal change. In this way, it is also possible to accurately detect whether the flexible clamp clamps the object, and the subsequent installation and connection are also very convenient. Once the object falls, the fingertip will return to its initial state due to its own elastic deformation. At this time, the detected part cannot be detected, and the above-mentioned detection signal will change rapidly, so that it can be discovered whether the object has fallen at the first time. The detection result is accurate and the feedback is fast.

[0020] Furthermore, since the driving chamber includes a cavity bottom wall and a cavity side wall, the cavity bottom wall is located between the fingers and arches toward the fingertips, the cavity side wall is connected to the finger heels of the fingers, the thickness of the cavity bottom wall is less than the thickness of the cavity side wall or the elastic modulus of the cavity bottom wall is less than the elastic modulus of the cavity side wall, and a tension reinforcement block for enhancing the pulling force is connected between the side wall and the cavity bottom wall of each finger. The cavity bottom wall that arches outward will deform and move closer to the top under negative pressure. The stroke will be greater, so the deformation amount will be greater, and the degree to which the fingers are closer to each other when clamping. It will be larger, thereby increasing the clamping force. In addition, due to the increase in the deformation stroke of the cavity bottom wall, the height of the driving chamber can be smaller, so that the deformation of the cavity side wall will be smaller, thus avoiding the situation where the clamping force becomes smaller due to the release of the clamping force due to the deformation of the cavity side wall. After the above structure is adopted, the negative pressure flexible clamp can provide greater clamping force, thereby clamping larger and heavier objects, and due to the presence of the tension reinforcement block, the pulling force of the deformation of the cavity bottom wall will be better transmitted to the finger, thereby increasing the pulling force and increasing the clamping force.

[0021] Furthermore, because the connecting portion further includes a cavity top wall, the communication port is provided on the cavity top wall. An anti-blocking structure is provided on the cavity top wall or cavity bottom wall to prevent deformation of the cavity bottom wall from blocking the communication port. The anti-blocking structure is located within the drive chamber. This anti-blocking structure prevents the cavity bottom wall from deforming due to negative pressure and thereby blocking the communication port, thereby ensuring a continuous negative pressure in the drive chamber and a stable clamping force of the flexible clamping jaws.

[0022] Because the drive chamber also includes an extension chamber extending toward the heel of each finger, a transitional curved surface is provided on the outer sidewall of the chamber, located adjacent to the heel. The lower end of the transitional curved surface is closer to the center of the flexible gripper than the upper end. This extension chamber facilitates greater deformation of the fingers during bending, increasing the bending angle and further enhancing the gripping force. The presence of this transitional curved surface also reduces deformation resistance at the heel of the fingers during bending, resulting in greater gripping force at the heel under the same negative pressure conditions.

[0023] Furthermore, since a reinforcement portion is provided at the upper end of the cavity side wall, the reinforcement portion extends toward the center to form a gathered shape, the upper end of the cavity side wall is bonded to or integrally formed with the cavity top wall, and the lower portion of the reinforcement portion is also provided with a functional surface for changing the direction of pressure so that the pressure is directed obliquely upward. In this way, the negative pressure flexible clamp can also be suitable for positive pressure. When the driving chamber is passed through positive pressure, the fingers will open, making it easier to clamp larger items. Under positive pressure, due to the presence of the reinforcement portion, the bonding force or strength between the cavity side wall and the cavity top wall can be increased. At the same time, the presence of the functional surface changes the direction of pressure acting on the functional surface by the air pressure, and the pressure will be borne by both the cavity side wall and the cavity top wall. This improves the strength, can effectively release the stress of material deformation under positive pressure, and improves the service life.

[0024] To solve the second technical problem, the present invention provides a method for detecting whether a flexible clamp is holding an object. The method utilizes the flexible clamp described above. When the flexible clamp is holding an object, a detection device is used to detect the bending deformation amplitude of the finger, the force applied to the fingertip, or the deformation amplitude of the drive chamber to determine whether the object is clamped.

[0025] S1. When the detection device detects the bending deformation amplitude of the fingers, the bending deformation amount of the fingers of the flexible clamping jaws gripping the object is set as the clamping bending deformation amount; the fingers of the flexible clamping jaws continuously deform and bend during the clamping action, and when the bending deformation amount of the fingers exceeds the preset clamping bending deformation amount, the detection signal of the detection device changes, and it is determined that the flexible clamping jaws do not grip the object at this time; if the detection signal of the detection device does not change throughout, it is determined that the bending deformation amount of the fingers of the flexible clamping jaws does not exceed the clamping bending deformation amount, indicating that the flexible clamping jaws grip the object;

[0026] S2. When the detection device detects the force applied to the fingertip of the finger, the detection device reflects the force applied to the fingertip by detecting the deformation of the fingertip. When the fingertip is deformed after the finger grips the object, the detection signal of the detection device changes, and it is determined that the flexible clamping claw grips the object; if the detection signal of the detection device does not change, it is determined that the flexible clamping claw does not grip the object;

[0027] S3. When the detection device detects the deformation amplitude of the driving chamber, a chamber wall with the largest deformation of the driving chamber is selected as the detected object, and the deformation of the detected object when the flexible clamp clamps the object is set as the clamping deformation; during the negative pressure clamping action of the flexible clamp, when the deformation of the detected object exceeds the clamping deformation, the detection signal of the detection device changes, and it is determined that the flexible clamp does not clamp the object at this time; if the detection signal of the detection device does not change, the deformation of the detected object does not exceed the clamping deformation, and it is determined that the flexible clamp clamps the object.

[0028] After adopting the above technical solution, the effect of the present invention is: the detection method can reflect whether an object is clamped by detecting the state of the flexible clamp itself, and can select a suitable detection method according to objects of different sizes and volumes and the on-site environment during use. The detection result is accurate and easy to achieve, which completely solves the current technical problem of difficulty in detecting whether the flexible clamp is clamping an object. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below with reference to the accompanying drawings and examples.

[0030] Figure 1 is a perspective view of embodiment 1 of the present invention;

[0031] Figure 2 is a cross-sectional view of Example 1 of the present invention;

[0032] Figure 3 is a perspective view of embodiment 2 of the present invention;

[0033] Figure 4 is a cross-sectional view of embodiment 2 of the present invention;

[0034] Figure 5 is a perspective view of embodiment 3 of the present invention;

[0035] Figure 6 is a cross-sectional view of Example 3 of the present invention;

[0036] Figure 7 is a perspective view of embodiment 4 of the present invention;

[0037] Figure 8 is a cross-sectional view of Example 4 of the present invention;

[0038] Figure 9is a cross-sectional view of another embodiment of the present invention;

[0039] Figure 10 is a perspective view of Example 5 of the present invention;

[0040] Figure 11 is a cross-sectional view of Example 5 of the present invention;

[0041] Figure 12 is another structural cross-sectional view of Example 5 of the present invention;

[0042] In the accompanying drawings: 1. Mounting seat; 2. Detection device; 21. Deflection detection sensor; 22. Detected piece; 221. Detected plate; 222. Shielding portion; 23. Connecting seat; 24. Clamping seat; 25. Fixed pole piece; 26. Elastic pole piece; 27. First pin; 28. First pressure detection pole piece; 29. Second pressure detection pole piece; 210. Second pin; 211. Photoelectric detection sensor; 212. Detected piece 1; 213. Magnetic detection sensor 1; 214. Detected rod; 215. Detected piece 2; 216. Magnetic Sex detection sensor 2; 217, guide rod; 3, flexible clamp; 31, connecting part; 311, driving chamber; 312, chamber side wall; 313, chamber bottom wall; 314, connecting port; 315, extension chamber; 316, chamber top wall; 317, reinforcement part; 318, functional surface; 32, clamping part; 321, finger; 322, tension reinforcement block; 323, limiting protrusion; 324, transition surface; 325. Deformation groove; 326. Groove inner wall; 327. Groove outer wall; 4, anti-blocking structure; 41, anti-blocking sleeve; 42, auxiliary through hole. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below through specific examples.

[0044] Example 1

[0045] like Figure 1 and Figure 2 As shown, a negative pressure flexible clamp includes a mounting base 1 and a flexible clamp 3 fixed on the mounting base 1, the flexible clamp 3 includes a clamping portion 32 and a connecting portion 31 made of elastic material, the clamping portion 32 includes at least two fingers 321 that cooperate with each other for clamping, the connecting portion 31 includes a driving chamber 311, and the connecting portion 31 is provided with a connecting port 314 that communicates with the driving chamber 311, and an air inlet and outlet joint connected to the connecting port 314 is installed on the mounting base 1, wherein the air inlet and outlet joint can be used to connect the flexible clamp 3 with an external vacuum device, which can be a vacuum pump or a vacuum generator. The mounting base 1 is a mechanical structure that facilitates the connection between the flexible clamp 3 and the robot arm, and the specific shape of the mounting base 1 can be adaptively modified according to actual assembly requirements.

[0046] A detection device 2 for detecting whether the finger 321 is clamping an object is installed on the flexible clamp 3 or on the flexible clamp 3 and the mounting seat 1. The detection device 2 is used to detect the bending deformation amplitude of the finger 321, or detect the force on the fingertip of the finger 321, or detect the deformation amplitude of the drive chamber 311.

[0047] In this embodiment, the detection device 2 is used to detect the bending deformation amplitude of the finger 321. Figure 1 and Figure 2 As shown, the detection device 2 includes a detected piece 22 fixedly mounted on the outside of the finger portion 321. The detected piece 22 deflects as the finger portion 321 bends. The mounting base 1 is provided with a deflection detection sensor 21 for detecting the deflection of the detected piece 22. One end of the detected piece 22 is fixed to a connecting base 23, which is bonded to the outside of the finger portion 321. When the finger portion 321 bends, the connecting base 23 moves with it, and changes in the position of the connecting base 23 cause the detected piece 22 to deflect. The bonding position of the connecting base 23 to the finger portion 321 can be optimized based on the detection sensitivity of the deflection detection sensor 21. When the bonding position of the connecting base 23 is closer to the fingertip, the deflection angle of the detected piece 22 will be greater under the same bending and deformation of the finger portion 321. Therefore, the bonding position can be optimized based on actual conditions.

[0048] Among them Figure 2 As shown, the detected sheet 22 of this embodiment is a sheet structure of metal material, and a detected plate portion 221 is provided on its upper end. The deflection detection sensor 21 adopts a proximity sensor, such as Figure 2 As shown, when the finger 321 is not bent, the detected plate portion 221 will be continuously detected by the proximity sensor, and when the finger 321 bends during the clamping process, the detected plate portion 221 will also deflect. When the finger 321 clamps an object, the detected plate portion 221 is still detected by the proximity sensor, and the entire detection signal does not change. When the flexible clamp 3 does not clamp an object, the bending amplitude of the finger 321 will increase, and the detected plate portion 221 will be out of the detection of the proximity sensor. Thus, the detection signal changes at this time, and the above-mentioned detection device 2 can accurately determine whether the flexible clamp 3 clamps an object. The detection device 2 is also relatively simple to set up. It does not directly detect the object, but detects the deformation change of the flexible clamp 3 itself. The detection result is accurate and the external interference is small, which solves the technical problem that the current flexible clamp is difficult to detect the clamped object.

[0049] This embodiment continues to optimize the design of the flexible clamp 3, which is made of silicone rubber. The driving chamber 311 includes a cavity bottom wall 313 and a cavity side wall 312. The cavity bottom wall 313 is located between the fingers 321 and arches toward the fingertips. The outside in the present invention is determined by the three-dimensional entity of the flexible clamp 3, the direction pointing to the inside of the three-dimensional entity is the inside, and the direction pointing to the outside of the three-dimensional entity is the outside; the cavity side wall 312 is connected to the finger heel of each finger 321, the thickness of the cavity bottom wall 313 is less than the thickness of the cavity side wall 312 or the elastic modulus of the cavity bottom wall 313 is less than the elastic modulus of the cavity side wall 312, and a tension reinforcement block 322 for enhancing the pulling force is connected between the side wall of each finger 321 and the cavity bottom wall 313. The number of fingers 321 in this embodiment can be two to five. The tension reinforcement block 322 can better pull the fingers 321 when the cavity bottom wall 313 is deformed, thereby driving the bending of the fingers 321 and increasing the pulling force. The increase in the pulling force also increases the clamping force of the fingers 321.

[0050] In this embodiment, the drive chamber 311 is further provided with an extension chamber 315 extending toward the heel of each finger 321. This extension chamber 315 facilitates greater deformation of the finger 321 during bending, increasing the bending angle of the finger 321, thereby further enhancing the clamping force. The length of the extension chamber 315 can be adjusted based on actual conditions and should not be too long. An excessively long extension chamber 315 will reduce the strength of the finger 321, which in turn reduces the clamping force. A transition surface 324 is provided on the outer side of the cavity sidewall 312 in the area adjacent to the finger heel. The lower end of the transition surface 324 is closer to the center of the flexible clamp 3 than the upper end. The lower end of the transition curved surface 324 is connected to the cavity bottom wall 313, and the upper end of the transition curved surface 324 is gradually connected to the cavity side wall 312. In this way, when the finger 321 is bent and deformed, the cavity side wall 312 will be squeezed in the area adjacent to the finger heel, and this squeezing will hinder the deformation of the finger heel. Due to the existence of the transition curved surface 324, the deformable space between the finger heels will become larger and the deformation resistance will be reduced. In this way, the clamping force of the finger heel will be greater under the same negative pressure conditions.

[0051] Example 2

[0052] like Figure 3 and Figure 4As shown, the structure of this embodiment is basically the same as that of embodiment 1, except that the structure of the detection device 2 is changed. In this embodiment, the deflection detection sensor 21 of the detection device 2 adopts a directed photoelectric detection sensor 211, and the upper end of the detected piece 22 is provided with a shielding portion 222 adapted to the photoelectric detection sensor 211. In the entire process of clamping the object, the finger 321 blocks the signal of the photoelectric detection sensor 211 from the initial deformation to the final clamping of the object. If the flexible clamp 3 does not clamp the object, the bending angle of the finger 321 increases, and the shielding portion 222 deviates from the shielding portion 222. At this time, the signal of the photoelectric detection sensor 211 is connected, so that a change in the detection signal occurs. According to the above principle, it is possible to accurately judge whether the flexible clamp 3 clamps the object.

[0053] Example 3

[0054] like Figure 5 and Figure 6 As shown, the structure of this embodiment is the same as that of embodiment 2, except that in this embodiment, the detected piece 22 is fixed to the finger portion 321 by means of a clamping seat 24. In this embodiment, the lower end of the detected piece 22 is fixed to the clamping seat 24, and the clamping seat 24 is wrapped around the outside of the finger portion 321 of the flexible clamping claw 3, and a limiting protrusion 323 is provided on the outside of the finger portion 321. The corresponding clamping seat 24 is provided with a limiting groove that cooperates with the limiting protrusion 323. In this way, after the clamping seat 24 wraps around the finger portion 321, the limiting protrusion 323 is located in the limiting groove. In this way, the clamping seat 24 is not easy to loosen or fall off. This structure facilitates the installation of the detected piece 22.

[0055] Example 4

[0056] like Figure 7 and Figure 8 As shown, the structure of the flexible clamping jaw 3 of this embodiment is basically the same as that of the embodiment 1, except that in this embodiment, a detection device 2 is installed on the flexible clamping jaw 3. The detection device 2 is used to detect the deformation amplitude of the driving chamber 311. In this embodiment, the driving chamber 311 includes a cavity side wall 312 and a cavity bottom wall 313. The deformation of the cavity bottom wall 313 is greater. Therefore, the detection device 2 in this embodiment directly detects the deformation of the cavity bottom wall 313.

[0057] The connecting portion 31 also includes a cavity top wall 316, and the communication port 314 is arranged on the cavity top wall 316. The cavity top wall 316 is provided with an anti-blocking structure 4 for preventing the deformed cavity bottom wall 313 from blocking the communication port 314. The anti-blocking structure 4 is located in the driving chamber 311. The anti-blocking structure 4 includes an anti-blocking sleeve 41 embedded in or bonded to the cavity top wall 316. The through cavity of the anti-blocking sleeve 41 is connected to the communication port 314. The side wall of the anti-blocking sleeve 41 is provided with an auxiliary through hole 42 for connecting the driving chamber 311 and the through cavity of the anti-blocking sleeve 41. The auxiliary through hole 42 can be a complete through hole or a notch. In this embodiment, a notch is preferably provided on the side wall of the end portion of the anti-blocking sleeve 41. The notch forms the auxiliary through hole 42. Therefore, when the cavity bottom wall 313 deforms and contacts the end portion of the anti-blocking sleeve 41, the communication port 314 is not blocked. The auxiliary through hole 42 remains open, thus ensuring a stable clamping force of the flexible clamping jaw 3. Of course, the anti-blocking structure 4 can also be provided on the cavity bottom wall 313. Similarly, when the cavity bottom wall 313 deforms, it can also be positioned to block the communication port 314.

[0058] Among them, such as Figure 8 As shown, the detection device 2 includes a deformation signal detection switch, which includes a fixed pole piece 25 and an elastic pole piece 26 fixed on the connecting portion 31 and located in the driving chamber 311. A gap is provided between the fixed pole piece 25 and the elastic pole piece 26. The positions of the fixed pole piece 25 and the elastic pole piece 26 are on the deformation path of the chamber wall (cavity bottom wall 313) of the driving chamber 311. The connecting portion 31 is provided with a first pin connected to the fixed pole piece 25 and the elastic pole piece 26 respectively. 27. The first pin 27 is connected to the electrical signal of the control device of the flexible clamping jaw 3. When the flexible clamping jaw 3 clamps an object, the deformation of the cavity bottom wall 313 is not enough to push the elastic pole piece 26 to make it contact with the fixed pole piece 25. Therefore, the detection signal does not change during the whole process. When the flexible clamping jaw 3 does not clamp an object, the deformation of the cavity bottom wall 313 increases to push the elastic pole piece 26 to contact with the fixed pole piece 25. At this time, the detection signal changes. Through this structure, it is possible to accurately detect whether an object is clamped.

[0059] In addition, in this embodiment, a reinforcement portion 317 is provided at the upper end of the cavity side wall 312, and the reinforcement portion 317 extends toward the center to form a gathered shape. The upper end of the cavity side wall 312 is bonded or integrally formed with the cavity top wall 316. The lower part of the reinforcement portion 317 is further provided with a functional surface 318 for changing the direction of pressure so that the pressure is directed obliquely upward. In this embodiment, the oblique upward refers to the Figure 8The placement position is determined, that is, the force exerted on the functional surface 318 will be obliquely upward, and the angle between the functional surface 318 and the extension direction of the finger 321 is greater than 90°, or the angle between the functional surface 318 and the extension direction of the cavity side wall 312 is greater than 90°, so that the direction of the pressure can be determined to be obliquely upward. When positive pressure is applied to the driving chamber 311, the finger portion 321 will open to facilitate the clamping of larger items. Under positive pressure, the force around the joint where the upper end of the cavity side wall 312 meets the cavity top wall 316 is very large. Due to the presence of the reinforcement portion 317, the bonding area between the cavity side wall 312 and the cavity top wall 316 can be increased, and the bonding force or strength can be increased. At the same time, due to the presence of the functional surface 318, the direction of the pressure acting on the functional surface 318 is changed. The direction of the pressure is perpendicular to the functional surface 318, so that the pressure change is borne by the cavity side wall 312 and the cavity top wall 316 together. This can effectively release the stress of material deformation under positive pressure, improve service life, and minimize the occurrence of tearing. Of course, the functional surface 318 does not have to be a plane, it can also be a curved surface.

[0060] In such Figure 9 As shown, Figure 9The structure of another detection device is disclosed in the literature. The detection device includes a deformation signal detection switch, which includes a detected rod 214 fixed to the bottom wall of the driving chamber. In this embodiment, a clamping block is provided at the lower end of the detected rod 214, and an embedding groove is provided on the corresponding bottom wall of the driving chamber. The clamping block can be fixed by being inserted into the embedding groove. The upper end of the detected rod 214 is provided with a detected member 215 made of a magnetic material or a metal material. At least two discretely distributed guide rods 215 are fixed to the detected rod 214. 17, the detected rod 214 extends into the air inlet and exhaust joint and the guide rod 217 cooperates with the inner hole of the air inlet and exhaust joint. The guide rod 217 facilitates the up and down movement of the detected rod 214 and plays a guiding role. The guide rod 217 is discretely distributed to form a flow channel to facilitate the passage of air. The mounting seat 1 or the air inlet and exhaust joint is provided with a magnetic detection sensor 216 or a metal detection sensor 2 for detecting the detected part 215. Therefore, when using this structure, air is extracted from the air inlet and exhaust joint to generate negative pressure for the flexible clamping claw, and the bottom wall of the driving chamber will move upward. When the flexible clamping claws 210 are deformed, the detected rod 214 will also move upward. Therefore, when the flexible clamping claws clamp an object, the detected piece 215 is detected by the magnetic detection sensor 216 or the metal detection sensor 2. However, the flexible clamping claws 210 do not clamp an object or the clamped object falls. At this time, the deformation of the cavity bottom wall will increase. At this time, the detected piece 215 will be out of the detection range of the magnetic detection sensor 216 or the metal detection sensor 2, so that the detection signal changes. Through the above detection principle, it is possible to accurately detect whether an object is clamped, and the guide rod 217 The detection rod 214 can be prevented from swinging, and the area between the guide rods 217 can facilitate the passage of gas, and the detection part 215 can be selected according to the material of the air inlet and exhaust joint. For example, when the material of the air inlet and exhaust joint is plastic, the detection part 215 can choose a magnet or metal. Correspondingly, the magnetic detection sensor 216 or the metal detection sensor 2 can detect the detection part 215. If the material of the air inlet and exhaust joint is metal, at this time, the detection part 215 chooses a magnet and uses the magnetic detection sensor 216 for detection.

[0061] Of course, the flow channel can also be set on the detected rod 214, that is, the guide rod 217 is not set at the upper end of the detected rod 214, but a guide platform is set at the upper end, and the guide platform is directly contacted and guided with the inner hole of the air inlet and exhaust joint. At the same time, an axial through hole is set on the detected rod 214 to form a flow channel, and a connecting hole connecting the flow channel and the driving chamber is set on the side wall of the lower end. This can also ensure that the detected rod 214 moves axially while facilitating the extraction of airflow.

[0062] Example 5

[0063] like Figure 10 and Figure 11 As shown, the structure of this embodiment is basically the same as that of embodiment 4, except that the detection device 2 on the flexible clamp 3 detects the force applied to the fingertip of the finger portion 321, as shown in FIG. Figure 10 As shown, the detection device 2 includes a pressure signal detection switch, and the pressure signal detection switch includes a first pressure detection electrode 28 and a second pressure detection electrode 29. The finger 321 is provided with a mounting groove on the clamping portion 32 for clamping an object, and the first pressure detection electrode 28 and the second pressure detection electrode 29 are installed in the mounting groove, wherein the mounting groove can be a mounting groove at the tip of the finger, or a mounting groove built into the finger 321. The first pressure detection electrode 28 and the second pressure detection electrode 29 can be built into the mounting groove during the molding process of the flexible clamp 3. A gap is provided between the first pressure detection electrode 28 and the second pressure detection electrode 29, and the finger 321 is provided with a second pin 210 connected to the first pressure detection electrode 28 and the second pressure detection electrode 29 respectively.

[0064] Similarly, when the flexible clamp 3 clamps an object, the fingertips of the finger 321 will be subjected to squeezing force, causing the first pressure detection electrode 28 and the second pressure detection electrode 29 to come close to each other and contact, thereby causing a signal change. If the flexible clamp 3 does not clamp an object, the fingertips of the finger 321 are not subjected to squeezing force, so the first pressure detection electrode 28 and the second pressure detection electrode 29 will not contact. The above structure can also accurately detect whether an object is clamped.

[0065] like Figure 12As shown in the figure, the structure of another pressure signal detection switch is illustrated, which includes a detection member 212 made of magnetic material or metal material, and a deformation groove 325 is provided on the fingertip of the finger portion 321 for facilitating deformation of the fingertip. The detection member 212 is fixed on the inner wall 326 of the deformation groove 325, and the outer wall 327 of the deformation groove is provided with a magnetic detection sensor 213 or a metal detection sensor for detecting the detection member 212. When the flexible clamping jaws clamp an object, the fingertips will deform and be stressed, and the opening of the deformation slot 325 will decrease, so that the detected part 212 will move closer to the magnetic detection sensor 213 or the metal detection sensor 1 and be detected. At this time, the signal will change, thereby determining that the object has been clamped. If the object is not clamped or the object falls, the inner wall 326 and the outer wall 327 of the deformation slot 325 will elastically deform, so that the detected part 212 will reset and leave the detection range of the magnetic detection sensor 213 or the metal detection sensor 1, so that it can accurately determine whether the object is clamped or whether the clamped object has fallen. Among them, the detected part 21 and the magnetic detection sensor 213 or the metal detection sensor 1 are installed on at least one fingertip of the multiple fingers of the flexible clamping jaws.

[0066] Example 6

[0067] This embodiment discloses a method for detecting whether a flexible clamp is holding an object. The method uses the flexible clamp described above. When the flexible clamp 3 is holding an object, the detection device 2 detects the bending deformation amplitude of the finger portion 321, the force applied to the fingertip of the finger portion 321, or the deformation amplitude of the drive chamber 311 to indirectly determine whether the object is clamped.

[0068] S1. When the detection device 2 detects the bending deformation amplitude of the finger 321, the bending deformation amount of the finger 321 of the flexible clamp 3 for clamping the object is set as the clamping bending deformation amount; the finger 321 of the flexible clamp 3 continues to deform and bend during the clamping action. When the bending deformation amount of the finger 321 exceeds the preset clamping bending deformation amount, the detection signal of the detection device 2 changes, and it is determined that the flexible clamp 3 has not clamped the object at this time; if the detection signal of the detection device 2 does not change at all, it is determined that the bending deformation amount of the finger 321 of the flexible clamp 3 does not exceed the clamping bending deformation amount, indicating that the flexible clamp 3 has clamped the object; the detection device 2 can adopt the structure in Example 1 or 2 or 3 to detect the bending deformation amount of the finger 321. The clamping bending deformation amount is different for different object volumes, and the clamping bending deformation amount can be optimized according to the size of the object to be clamped.

[0069] S2. When the detection device 2 detects the force on the fingertip of the finger portion 321, the detection device 2 reflects the force on the fingertip by detecting the deformation of the fingertip. When the fingertip is deformed after the finger portion 321 clamps the object, the detection signal of the detection device 2 changes, and it is determined that the flexible clamp 3 clamps the object; if the detection signal of the detection device 2 does not change, it is determined that the flexible clamp 3 does not clamp the object; the detection device 2 can adopt the structure in Example 5 to detect the force on the fingertip. After the fingertip clamps the object, it will be subjected to a squeezing force, so that the first pressure detection electrode and the second pressure detection electrode are close to each other and contact, thereby causing a signal change. If the object is not clamped, the fingertip of the finger portion 321 is not subjected to a squeezing force, and the first pressure detection electrode and the second pressure detection electrode will not contact. The above principle can also accurately detect whether the object is clamped.

[0070] S3. When the detection device 2 detects the deformation amplitude of the driving chamber 311, the chamber wall with the largest deformation of the driving chamber 311 is selected as the detected object, and the deformation of the detected object when the flexible clamp 3 clamps the object is set as the clamping deformation; when the deformation of the detected object exceeds the clamping deformation during the negative pressure clamping action of the flexible clamp 3, the detection signal of the detection device 2 changes, and it is determined that the flexible clamp 3 has not clamped the object at this time; if the detection signal of the detection device 2 does not change, the deformation of the detected object does not exceed the clamping deformation, and it is determined that the flexible clamp 3 has clamped the object. The detection device 2 can use the structure in Example 4. During the negative pressure clamping process of the flexible clamp 3, the deformation of the driving chamber 311 also indirectly reflects the bending deformation of the flexible clamp 3. Therefore, whether the object is clamped can be reflected by integrating the deformation of the cavity bottom wall 313 for detecting the driving chamber 311 on the flexible clamp 3. The deformation of the cavity bottom wall 313 is large, so it is more appropriate to detect the deformation of the cavity bottom wall 313 and it is easier to detect.

[0071] Of course, another structure in Example 4 can also be adopted, in which the detection device 2 detects the extension and contraction of the detected rod 214, and the detected rod 214 is fixed on the bottom wall of the cavity. In this way, the deformation of the bottom wall of the cavity is reflected by the extension and contraction of the detected rod 214. When the flexible clamping claw clamps the object, the second detected member 215 on the detected rod 214 is continuously detected by the corresponding sensor, which indicates that the object is clamped. If the second detected member 215 on the detected rod 214 is continuously detected by the corresponding sensor and then the signal changes and becomes undetected, it indicates that the detected rod 214 has moved upward too far and has left the detection range of the corresponding sensor. At this time, it reflects that the bending amplitude of the finger of the flexible clamping claw is too large, and the flexible clamping claw has not clamped the object.

[0072] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Various modifications and alterations to the technical solutions of the present invention without departing from the spirit of the present invention shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A negative pressure flexible clamp, comprising a mounting seat (1) and a flexible clamping claw (3) fixed to the mounting seat (1), the flexible clamping claw (3) comprising a clamping portion (32) and a connecting portion (31) made of elastic material, the clamping portion (32) comprising at least two fingers (321) cooperating with each other for clamping, the connecting portion (31) comprising a driving chamber (311), the connecting portion (31) being provided with a communication port (314) communicating with the driving chamber (311), the mounting seat (1) being provided with an air inlet and outlet joint connected to the communication port (314), and the invention is characterized in that: A detection device (2) for detecting whether the finger (321) is holding an object is installed on the flexible clamp (3) or on the flexible clamp (3) and the mounting seat (1), and the detection device (2) is used to detect the deformation amplitude of the drive chamber (311); the detection device (2) includes a deformation signal detection switch, and the deformation signal detection switch includes a detected rod (214) fixed on the bottom wall (313) of the drive chamber (311), and the upper end of the detected rod (214) is provided with a detected part 2 (215) made of magnetic material or metal material, and the detected rod (214) extends into the air inlet and exhaust joint and is guided with the inner hole of the air inlet and exhaust joint. A magnetic detection sensor 2 (216) or a metal detection sensor 2 for detecting the detected part 2 (215) is provided on the mounting seat (1) or the air inlet and exhaust joint, and a flow channel for facilitating gas flow is provided on the detected rod (214) or between the detected rod and the air inlet and exhaust joint.

2. A negative pressure flexible clamp according to claim 1, characterized in that: The driving chamber (311) includes a cavity bottom wall (313) and a cavity side wall (312), wherein the cavity bottom wall (313) is located between each finger portion (321) and arches toward the fingertip, and the cavity side wall (312) is connected to the finger heel of each finger portion (321). The thickness of the cavity bottom wall (313) is smaller than the thickness of the cavity side wall (312) or the elastic modulus of the cavity bottom wall (313) is smaller than the elastic modulus of the cavity side wall (312), and a tension reinforcement block (322) for enhancing the pulling force is connected between the side wall of each finger portion (321) and the cavity bottom wall (313).

3. A negative pressure flexible clamp according to claim 2, characterized in that: The connecting portion (31) further includes a cavity top wall (316), the communication port (314) is arranged on the cavity top wall (316), and an anti-blocking structure (4) is provided on the cavity top wall (316) or the cavity bottom wall (313) to prevent the deformed cavity bottom wall (313) from blocking the communication port (314), and the anti-blocking structure (4) is located in the driving chamber (311).

4. A negative pressure flexible clamp according to claim 3, characterized in that: The driving chamber (311) is further provided with an extension chamber (315) extending toward the heel of each finger (321), and a transition surface (324) is provided on the outer side of the chamber side wall (312) in an area adjacent to the heel of the finger, wherein the lower end of the transition surface (324) is closer to the center of the flexible clamp (3) than the upper end.

5. The negative pressure flexible clamp according to claim 4, characterized in that: A reinforcement portion (317) is provided at the upper end of the cavity side wall (312), and the reinforcement portion (317) extends toward the center to form a gathered shape. The upper end of the cavity side wall (312) is bonded to or integrally formed with the cavity top wall (316), and the lower portion of the reinforcement portion (317) is further provided with a functional surface (318) for changing the direction of pressure so that the pressure is directed obliquely upward.

6. A method for detecting whether a flexible clamp is holding an object, characterized in that: The method uses the flexible clamp as claimed in claim 1, and when the flexible clamp (3) clamps an object, the detection device (2) detects the bending deformation amplitude of the finger (321) or the deformation amplitude of the driving chamber (311) to determine whether the object is clamped; when the detection device (2) detects the deformation amplitude of the driving chamber (311), a chamber wall of the driving chamber (311) with the largest deformation is selected as the detected object, and the deformation of the detected object when the flexible clamp (3) clamps the object is set as the clamping deformation; during the negative pressure clamping action of the flexible clamp (3), when the deformation of the detected object exceeds the clamping deformation, the detection signal of the detection device (2) changes, and it is determined that the flexible clamp (3) does not clamp the object at this time; if the detection signal of the detection device (2) does not change, the deformation of the detected object does not exceed the clamping deformation, and it is determined that the flexible clamp (3) clamps the object.

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