Screw locking machine capable of automatically replacing head

Abstract

The utility model discloses a screw locking machine capable of automatically replacing a head, which relates to the field of automatic screw locking, and comprises a quick-change tightening head, a matched screwdriver head, a suction nozzle, an annular clamping groove formed in the middle of the quick-change tightening head, and a telescopic disassembly and assembly mechanism which comprises a fixed sleeve, a first cylinder and a sliding sleeve; a communicating block is further arranged at the top of the fixing sleeve, air source connectors communicating with the suction nozzles are arranged on the two sides of the communicating block, and the air source connectors are connected with negative pressure equipment to enable the suction nozzles to form negative pressure to conduct vacuum adsorption on the screws. Through cooperation of a fixed sleeve, a first air cylinder, a sliding sleeve and a steel ball which are arranged on the telescopic dismounting and mounting mechanism, automatic dismounting and replacement of the quick-change tightening head are achieved, and automatic replacement of a screwdriver head and a suction nozzle is achieved. And meanwhile, the screwdriver head and the suction nozzle are matched with the air source connector to form negative pressure at the suction nozzle position, so that vacuum adsorption of screws matched with the screwdriver head and the suction nozzle is realized, the existing operation of manually replacing the screwdriver head and the suction nozzle is replaced, the replacement time is greatly shortened, and the production efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of automatic screw fastening, and in particular to an automatic screw fastening machine with an automatic head-changing mechanism. Background Technology

[0002] Automatic screw fastening machines use various electric and pneumatic components to automatically feed, tighten, and inspect screws. This equipment simplifies the screw fastening process, reducing the number of workers and minimizing human error. It is a typical non-standard automated equipment. The main components of an automatic screw fastening machine include an automatic screw feeder, a fastening mechanism, a power supply box, and a positioning system. The fastening mechanism uses an electric screwdriver, pneumatic screwdriver, or servo motor to perform the screw-tightening action according to a programmed sequence, completely replacing manual labor.

[0003] Currently, automatic screw fastening machines on the market can be divided into handheld automatic screw fastening machines and fully automatic screw fastening machines. Traditional handheld automatic screw fastening machines can provide data feedback such as torque, but screw feeding still requires manual operation. Therefore, handheld automatic screw fastening machines have emerged, which add magnetic suction mechanisms for ordinary metal screws and use screw escape mechanisms to automatically feed non-metallic screws. Compared to traditional handheld automatic screw fastening machines, they have achieved further functional improvements and increased efficiency in production applications. However, handheld automatic screw fastening machines cannot achieve complete automation; the emergence of fully automatic screw fastening machines has realized true production automation.

[0004] However, common fully automatic screw machines can only install one type of quick-change screw tightening head. A single machine cannot install multiple types of screws. To complete the installation of different types of screws, the quick-change tightening head needs to be changed manually. The entire replacement process is time-consuming and affects production efficiency. Utility Model Content

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides an automatic head-changing screw fastening machine to solve the problems existing in the background art.

[0006] This utility model provides the following technical solution: an automatic head-changing screw fastening machine, comprising:

[0007] The quick-change tightening head has an annular groove in the middle. The bottom of the quick-change tightening head is equipped with a screwdriver bit and a suction nozzle. The top of the quick-change tightening head is also equipped with an air source connector that communicates with the suction nozzle. The screwdriver bit, suction nozzle, and air source connector are used to vacuum adsorb screws to complete the assembly.

[0008] The telescopic assembly and disassembly mechanism includes a fixed sleeve, a first cylinder, and a sliding sleeve. The fixed sleeve and the sliding sleeve are slidably assembled, and a steel ball is provided between them. When the first cylinder drives the sliding sleeve to rise and fall, the steel ball is engaged or disengaged from the annular groove provided on the quick-change tightening head, so as to realize the installation and disassembly of the telescopic assembly and disassembly mechanism and the quick-change tightening head.

[0009] Preferably, the fixed sleeve has an assembly groove for assembling a steel ball, and the side of the sliding sleeve that contacts the fixed sleeve has a groove in the middle. When the sliding sleeve moves upward, the groove and the assembly groove are misaligned, and the steel ball is stuck in the annular groove under the abutment of the inner wall of the sliding sleeve. At this time, the quick-change tightening head tightens the assembly. When the sliding sleeve moves downward, until the groove of the steel ball is flush with the assembly groove, the steel ball loses the abutment force and is pressed into the groove by the weight of the quick-change tightening head. At this time, the quick-change tightening head falls down and is removed.

[0010] Preferably, the assembly groove has two corresponding upper and lower blocking protrusions on the side near the quick-change tightening head. The distance between the two blocking protrusions is less than the diameter of the steel ball, so that the steel ball cannot enter the fixed sleeve.

[0011] Preferably, the telescopic locking mechanism further includes a return spring disposed between the fixed sleeve and the sliding sleeve.

[0012] Preferably, it also includes a three-axis robot and a mounting base. The movable end of the three-axis robot is equipped with an electric screwdriver, and the output end of the electric screwdriver is provided with a coupling for connecting to a quick-change tightening head. The mounting base is used to place two or more quick-change tightening heads of different types, and is used to cooperate with the three-axis robot and the telescopic disassembly and assembly mechanism to complete the disassembly and placement of the quick-change tightening heads.

[0013] Preferably, the quick-change tightening head further includes a connector that plugs into the connecting shaft. The connector is provided with a hexagonal groove, and the bottom of the connecting shaft is provided with a hexagonal profile that matches the hexagonal groove, so as to realize that the connecting shaft drives the quick-change tightening head to rotate synchronously.

[0014] Preferably, the quick-change tightening head further includes a bit retraction spring disposed at the bottom of the connector, wherein the connector is elastically connected to the middle of the quick-change tightening head through the bit retraction spring, and a sensor is disposed at the connection point between the top of the connector and the coupling shaft to detect whether the connector has moved down to identify whether the connector and the coupling shaft are connected.

[0015] Preferably, the quick-change tightening head further includes a boss placed on the mounting base.

[0016] Preferably, the mounting base includes a base, a placement groove, a second cylinder, and a locking block. The base has at least two placement grooves that are adapted to the protrusions of the quick-change tightening head. A second cylinder is provided on one side of the placement groove on the base, and the piston end of the second cylinder is connected to the locking block.

[0017] Preferably, the front end of the locking block is provided with a semi-circular groove, which is used to lock in the middle of the quick-change tightening head to block the boss.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] 1. This utility model pre-assembles matching screwdriver bits and nozzles inside different quick-change tightening heads. Through the fixed sleeve, first cylinder, sliding sleeve, and steel ball set by the telescopic disassembly and assembly mechanism, the quick-change tightening heads are automatically disassembled and replaced, thereby achieving the purpose of automatically changing screwdriver bits and nozzles. At the same time, the nozzle, in conjunction with the negative pressure device connected to the air source connector, creates negative pressure at the nozzle position, thereby achieving vacuum suction of screws, replacing the existing manual operation of changing screwdriver bits and nozzles, greatly reducing the time required for replacement, and thus improving production efficiency.

[0020] 2. After the quick-change tightening head is assembled, the top of the quick-change tightening head abuts against the fixed sleeve, thereby connecting the nozzle, the connecting block, and the air source connector to achieve the purpose of negative pressure adsorption of the screw. At the same time, a sealing ring is provided inside the fixed sleeve. The top of the assembled quick-change tightening head abuts against the sealing ring, thereby increasing the sealing between the quick-change tightening head and the fixed sleeve, and thus maintaining good sealing between the nozzle, the connecting block, and the air source connector, so that the nozzle can stably adsorb the screw and maintain a stable movement state.

[0021] 3. This utility model adds a second cylinder and a locking block to the mounting base. When unloading, the second cylinder drives the locking block to move towards the placement groove until the semi-circular groove contacts the center of the quick-change tightening head. The locking block then blocks the protrusion of the quick-change tightening head to prevent the quick-change tightening head from having a force between it and the telescopic locking mechanism, which would prevent the quick-change tightening head from falling down to unload by gravity, thus ensuring the stability of unloading the quick-change tightening head. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the telescopic clamping mechanism and quick-change tightening head assembly of this utility model.

[0023] Figure 2 This is a schematic diagram of the cross-sectional structure of the telescopic clamping mechanism and quick-change tightening head assembly of this utility model.

[0024] Figure 3 For the present utility model Figure 2 Enlarged structural diagram at point A in the middle.

[0025] Figure 4 This is a schematic diagram of the mounting base structure of this utility model.

[0026] Figure 5 This is a schematic diagram of the overall three-dimensional structure of this utility model.

[0027] The attached figures are labeled as follows: 1. Quick-change tightening head; 11. Annular groove; 12. Connector; 13. Boss; 2. Fixing sleeve; 21. Assembly groove; 211. Barrier protrusion; 3. First cylinder; 4. Sliding sleeve; 41. Groove; 42. Return spring; 5. Sensor; 6. Steel ball; 7. Screwdriver bit; 71. Screwdriver bit retraction spring; 8. Suction nozzle; 81. Suction nozzle buffer spring; 9. Sealing ring; 20. Three-axis robot; 30. Electric screwdriver; 40. Coupling shaft; 50. Connecting block; 60. Air source connector; 70. Mounting base; 701. Base; 702. Placement groove; 703. Second cylinder; 704. Clamping block. Detailed Implementation

[0028] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more definite definition of the scope of protection of the present invention.

[0029] This utility model provides an automatic head-changing screw fastening machine, such as... Figure 1-5 As shown, it includes a three-axis robot arm 20, an electric screwdriver 30, a coupling 40, a telescopic disassembly and assembly mechanism, two quick-change tightening heads 1, and a mounting base 70.

[0030] The movable end of the three-axis robot 20 is equipped with an electric screwdriver 30, and the output end of the electric screwdriver 30 is connected to a coupling 40.

[0031] Each quick-change tightening head 1 has an annular groove 11 in the middle. A screwdriver bit 7 and a suction nozzle 8 can be installed inside the quick-change tightening head 1. Specifically, the screwdriver bit 7 extends vertically through the entire quick-change tightening head 1, and the suction nozzle 8 is located at the bottom of the quick-change tightening head 1, and is sealed to the quick-change tightening head 1. It should be noted that the screwdriver bit 7 and suction nozzle 8 are installed according to the company's production needs, so that the screwdriver bit 7 and suction nozzle 8 on a single quick-change tightening head 1 correspond to the appropriate screws.

[0032] The telescopic assembly and disassembly mechanism includes a fixed sleeve 2, a first cylinder 3, and a sliding sleeve 4. The fixed sleeve 2 and the sliding sleeve 4 are slidably assembled, and a steel ball 6 is provided between them. When the first cylinder 3 drives the sliding sleeve 4 to rise and fall, the steel ball 6 is engaged or disengaged from the annular groove 11 provided on the quick-change tightening head 1, so as to realize the installation and disassembly of the telescopic assembly and disassembly mechanism and the quick-change tightening head 1.

[0033] A connecting block 50 is also provided at the top of the fixed sleeve 2. Air source connectors 60 connected to the suction nozzle 8 are provided on both sides of the connecting block 50. The air source connectors 60 are connected to the negative pressure device to create a negative pressure at the suction nozzle 8, thereby achieving vacuum adsorption of the screw.

[0034] The fixed sleeve 2 of the telescopic assembly and disassembly mechanism is mounted on the bottom of the movable end of the three-axis robot 20 and is in a vertical relationship with the electric screwdriver 30, so that one end of the connecting shaft 40 can pass through the telescopic assembly and disassembly mechanism and be inserted into the quick-change tightening head 1, so that the electric screwdriver 30 drives the quick-change tightening head 1 to rotate synchronously through the connecting shaft 40.

[0035] Mounting base 70 is placed on the bottom side away from the three-axis robot 20, and is used to place two quick-change tightening heads 1 of different types, which are used to cooperate with the three-axis robot 20 and the telescopic disassembly and assembly mechanism to complete the disassembly and assembly of quick-change tightening heads 1.

[0036] The quick-change tightening head 1 is elastically clamped by the fixed sleeve 2, first cylinder 3, sliding sleeve 4, and steel ball 6 set by the telescopic disassembly and assembly mechanism. When the first cylinder 3 drives the sliding sleeve 4 to move upward, the steel ball 6 enters the annular groove 11 set in the quick-change tightening head 1, so that the quick-change tightening head 1 is rotated and assembled with the fixed sleeve 2. The quick-change tightening head 1 can be driven to rotate by the electric screwdriver 30 and the connecting shaft 40. When the first cylinder 3 drives the sliding sleeve 4 to move downward, the steel ball 6 disengages from the annular groove 11. Under gravity, the quick-change tightening head 1 falls and separates from the fixed sleeve 2, realizing the disassembly and replacement of the quick-change tightening head 1, thereby achieving the purpose of automatically changing the screwdriver bit and nozzle. When adsorbing screws, the negative pressure device connected by the air source connector 60 is used to create negative pressure on the nozzle 8 to vacuum adsorb the screws, replacing the existing manual replacement operation, greatly reducing the replacement time, and thus improving production efficiency.

[0037] Furthermore, an assembly groove 21 for assembling the steel ball 6 is provided on the fixed sleeve, and a groove 41 is provided in the middle of the side of the sliding sleeve 4 that contacts the fixed sleeve. When the first cylinder 3 drives the sliding sleeve 4 to move upward, the groove 41 and the assembly groove 21 are misaligned, and the steel ball 6 is stuck in the annular groove 11 under the abutment of the inner wall of the sliding sleeve 4. At this time, the quick-change tightening head 1 and the telescopic disassembly and assembly mechanism realize rotational assembly.

[0038] When the first cylinder 3 drives the sliding sleeve 4 to move down until the groove 41 of the steel ball 6 is flush with the assembly groove 21, the steel ball 6 loses the resistance of the inner wall of the sliding sleeve 4 and is pressed by the gravity of the quick-change tightening head 1 to the assembly groove 21 and the groove 41. At this time, the quick-change tightening head 1 falls down and is removed.

[0039] Furthermore, two corresponding upper and lower blocking protrusions 211 are provided on the side of the assembly groove 21 near the quick-change tightening head 1. The distance between the two blocking protrusions 211 is less than the diameter of the steel ball 6, so that the steel ball 6 cannot enter the fixed sleeve.

[0040] In this embodiment, a sealing ring 9 is provided inside the fixed sleeve 2. The top of the assembled quick-change tightening head 1 abuts against the sealing ring 9 to seal the connection position between the quick-change tightening head 1 and the fixed sleeve 2, so that the suction nozzle 8, the connecting block 50, and the air source connector 60 are sealed together. Under the action of the sealing ring 9, the top of the assembled quick-change tightening head 1 abuts against the sealing ring 9, thereby increasing the sealing between the quick-change tightening head 1 and the fixed sleeve 2, and thus maintaining good sealing between the suction nozzle 8, the connecting block 50, and the air source connector 60, so that the suction nozzle 8 can stably adsorb the screw and maintain a stable movement state.

[0041] In this embodiment, the telescopic disassembly and assembly mechanism also includes a return spring 42 disposed between the fixed sleeve and the sliding sleeve 4. The return spring 42 is used to assist the first cylinder 3 in driving the sliding sleeve 4 to return upward.

[0042] In this embodiment, the top of the bit 7 is also provided with a connector 12 and a bit retraction spring 71. The connector 12 is used to connect with the connecting shaft 40, and the bit retraction spring 71 is disposed between the connector 12 and the bit 7 to buffer the impact when the bit 7 is connected to the screw.

[0043] Furthermore, the connector 12 is provided with a hexagonal groove 41, and the bottom of the connecting shaft 40 is provided with a hexagonal contour that matches the hexagonal groove 41, so as to realize that the connecting shaft 40 drives the quick-change tightening head 1 to rotate synchronously.

[0044] To enable the connection between the connector 12 and the shaft 40, a sensor 5 is provided at the connection point between the top of the connector 12 and the shaft 40. This sensor is used to detect whether the connector 12 has moved down to identify whether the connector 12 and the shaft 40 are connected.

[0045] When the connecting shaft 40 presses down on the connector 12, that is, the connecting shaft 40 and the connector are not precisely aligned and the connecting shaft 40 is not inserted into the hexagonal groove 41 provided in the connector 12, at this time, the sensor 5 detects that the connector 12 has moved down and sends a signal to drive the electric screwdriver 30 to rotate the connecting shaft 40. When the hexagonal outline of the connecting shaft 40 coincides with the hexagonal groove 41, the connector 12 rises back to its original position under the elastic force of the screwdriver bit retraction spring 71, thus completing the connection with the connecting shaft 40.

[0046] In this embodiment, a suction nozzle buffer spring 81 is also provided on the top of the suction nozzle 8. The other end of the suction nozzle buffer spring 81 abuts against the inner wall of the quick-change tightening head 1 to buffer the impact when the suction nozzle 8 picks up the screw.

[0047] In this embodiment, the quick-change tightening head 1 also includes a boss 13 placed on the mounting base 70, and the outer diameter of the boss 13 is larger than the diameter of the middle part of the quick-change tightening head 1.

[0048] In this embodiment, the mounting base 70 includes a base 701, a placement groove 702, a second cylinder 703, and a locking block 704. At least two placement grooves 702 are provided on the base 701. The placement grooves 702 are adapted to the protrusions 13 provided on the quick-change tightening head 1. The second cylinder 703 is provided on one side of the placement groove 702 on the base 701. The piston end of the second cylinder 703 is connected to the locking block 704.

[0049] Furthermore, the front end of the locking block 704 is provided with a semi-circular groove 41, which is used to lock in the middle of the quick-change tightening head 1 to block the boss 13.

[0050] When the three-axis robot 20 drives the telescopic disassembly and assembly mechanism and the quick-change tightening head 1 to the placement slot 702, after the telescopic disassembly and assembly mechanism removes the quick-change tightening head 1, the second cylinder 703 drives the locking block 704 to move towards the placement slot 702 until the semi-circular groove 41 contacts the middle of the quick-change tightening head 1. Thus, the locking block 704 blocks the boss 13 of the quick-change tightening head 1 to prevent there from being in contact with the telescopic disassembly and assembly mechanism, which would prevent the quick-change tightening head 1 from falling down and unloading by gravity, thus ensuring the stability of unloading the quick-change tightening head 1.

[0051] The working principle of this utility model:

[0052] The three-axis robot 20 moves the electric screwdriver 30, the coupling 40, the telescopic disassembly and assembly mechanism, and the quick-change tightening head 1 to the top of the mounting base 70, and aligns the quick-change tightening head 1 with the second cylinder 703.

[0053] Then, the first cylinder 3 drives the sliding sleeve 4 to move down until the groove 41 of the steel ball 6 is flush with the assembly groove 21. The steel ball 6 loses the resistance of the inner wall of the sliding sleeve 4 and is pressed by the gravity of the quick-change tightening head 1 to the assembly groove 21 and the groove 41. At this time, the quick-change tightening head 1 falls down and is removed to the inside. At the same time, the second cylinder 703 drives the locking block 704 to move towards the placement groove 702 until the semi-circular groove 41 contacts the middle of the quick-change tightening head 1, thereby using the locking block 704 to block the boss 13 of the quick-change tightening head 1.

[0054] Subsequently, the three-axis robot 20 moves the electric screwdriver 30, coupling 40, telescopic disassembly and assembly mechanism, and quick-change tightening head 1 directly above another quick-change tightening head 1 to be replaced, and completely covers the top of the quick-change tightening head 1 until the assembly groove 21 corresponds to the annular slot 11. At this time, when the first cylinder 3 drives the sliding sleeve 4 to move upward, the groove 41 and the assembly groove 21 are misaligned, and the sliding sleeve 4 pushes the steel ball 6 into the annular slot 11, and the side wall of the sliding sleeve 4 always abuts against the steel ball 6, so that the quick-change tightening head 1 and the telescopic disassembly and assembly mechanism can rotate and assemble.

[0055] Several points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection" and "linkage" should be interpreted broadly, and can be mechanical or electrical connection, or internal connection between two components, or direct connection. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationship. When the absolute position of the described object changes, the relative positional relationship may change.

[0056] The above description is only a preferred embodiment of the present utility model. The protection scope of the present utility model is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present utility model should be included in the protection scope recorded in the claims.

Claims

1. An automatic head-changing screw fastening machine, characterized in that, include: The quick-change tightening head is provided in at least two parts for assembling matching screwdriver bits and nozzles. A ring-shaped groove is provided in the middle of the quick-change tightening head. The telescopic assembly and disassembly mechanism includes a fixed sleeve, a first cylinder and a sliding sleeve, wherein the fixed sleeve and the sliding sleeve are slidably assembled, and a steel ball is movably assembled inside the fixed sleeve. When the first cylinder drives the sliding sleeve to rise and fall, the sliding sleeve squeezes or releases the steel ball and forms a snap-fit ​​or disengagement state with the annular groove set in the quick-change tightening head, so as to realize the installation and disassembly of the telescopic disassembly mechanism and the quick-change tightening head, that is, to automatically change different types of screwdriver bits and nozzles. The top of the fixed sleeve is also provided with a connecting block, and air source connectors connected to the suction nozzle are provided on both sides of the connecting block. The air source connectors are connected to the negative pressure device to create negative pressure in the suction nozzle to vacuum adsorb the screw.

2. The automatic head-changing screw fastening machine according to claim 1, characterized in that: The fixed sleeve has an assembly groove for assembling a steel ball. The side of the sliding sleeve that contacts the fixed sleeve has a groove in the middle. When the sliding sleeve moves upward, the groove and the assembly groove are misaligned. The steel ball is stuck in the annular groove under the abutment of the inner wall of the sliding sleeve. At this time, the quick-change tightening head tightens the assembly. When the sliding sleeve moves downward, until the groove of the steel ball is flush with the assembly groove, the steel ball loses the abutment force and is pressed into the groove by the weight of the quick-change tightening head. At this time, the quick-change tightening head falls down and is removed.

3. The automatic head-changing screw fastening machine according to claim 2, characterized in that: The assembly slot has two corresponding upper and lower blocking protrusions on the side near the quick-change tightening head. The distance between the two blocking protrusions is smaller than the diameter of the steel ball, so that the steel ball cannot enter the fixed sleeve.

4. The automatic head-changing screw fastening machine according to claim 2, characterized in that: A sealing ring is provided inside the fixed sleeve. The top of the assembled quick-change tightening head abuts against the sealing ring to seal the connection between the quick-change tightening head and the fixed sleeve, thereby sealing the connection between the nozzle, the connecting block, and the air source connector.

5. A screw fastening machine with automatic head changing according to any one of claims 1-4, characterized in that: It also includes a three-axis robot and a mounting base. The moving end of the three-axis robot is equipped with an electric screwdriver. The output end of the electric screwdriver is provided with a coupling that connects to a quick-change tightening head. The mounting base is used to place two or more quick-change tightening heads of different types, which are used to cooperate with the three-axis robot and the telescopic disassembly and assembly mechanism to complete the disassembly and placement of the quick-change tightening heads.

6. The automatic head-changing screw fastening machine according to claim 5, characterized in that: The top of the bit is also provided with a connector and a bit retraction spring. The connector is used to connect with the shaft, and the bit retraction spring is located between the connector and the bit to buffer the impact when the bit is connected to the screw.

7. The automatic head-changing screw fastening machine according to claim 6, characterized in that: The top of the suction nozzle is also equipped with a suction nozzle buffer spring, and the other end of the suction nozzle buffer spring abuts against the inner wall of the quick-change tightening head to buffer the impact when the suction nozzle picks up the screw.

8. The automatic head-changing screw fastening machine according to claim 6, characterized in that: A sensor is installed at the connection point between the top of the connector and the shaft to detect whether the connector has moved down in order to identify whether the connector and the shaft are connected.

9. The automatic head-changing screw fastening machine according to claim 5, characterized in that: The quick-change tightening head also includes a boss placed on the mounting base.

10. A screw fastening machine with automatic head changing according to claim 5, characterized in that: The mounting base includes a base, a placement slot, a second cylinder, and a locking block. The base has at least two placement slots that are adapted to the protrusions on the quick-change tightening head. A second cylinder is located on one side of the placement slot on the base. The piston end of the second cylinder is connected to the locking block. The front end of the locking block has a semi-circular groove for locking in the middle of the quick-change tightening head to block the protrusion.

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