Transmission mechanism with self-checking function

Abstract

The invention relates to a transmission mechanism with a self-checking function. The transmission mechanism is arranged in an anastomat body of an electric anastomat. A driver is installed at the front end of the anastomat body in a sliding mode, and the driver is connected with an osculating assembly arranged on the electric anastomat. The transmission mechanism comprises a rack; a stroke buffer structure; a motor assembly; and a main PCBA board. And the transmission mechanism with the self-checking capability is utilized to ensure that the motor assembly can work normally before the osculating assembly is really triggered, so that the safety is improved. According to the transmission mechanism, the motor output gear and the rack are matched for transmission, the number of rod pieces of the transmission mechanism is small, the influence of friction and motion interference between the rod pieces on the transmission efficiency is effectively reduced, the efficient transmission rate is guaranteed, and meanwhile the transmission stability is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of medical devices, in particular to a transmission mechanism with self-checking function. BACKGROUND

[0002] Minimally invasive surgery is to achieve the same good effect as open surgery with as little or no trauma, as little damage or no damage to the patient's internal environment (local or systemic) state. As a kind of minimally invasive surgical instrument, an anastomat is often used for cutting and suturing tissues in some surgical operations. The existing anastomat is divided into two types: manual firing and electric firing. Manual firing is to press the handle to transmit force to the anastomosis assembly in a purely mechanical way to complete the firing action. A huge firing force is required to complete the anastomosis of the tissue during the firing process, which requires a high level of operator skill. Insufficient firing force will result in incomplete cutting and closing of the tissue, causing surgical accidents.

[0003] The current electric firing anastomat mainly converts the rotary motion of the internal motor into the expected motion through the transmission mechanism to realize the cutting and closing of the tissue by the anastomosis assembly. If the motor fails when the anastomat is in use, it may cause surgical risks. The existing anastomat motor means the use of the anastomosis assembly once it is running. If the motor failure can be detected before the anastomat is put into use, the safety of the surgery can be effectively improved, and potential surgical accidents can be prevented. SUMMARY

[0004] The purpose of the present application is to provide a transmission mechanism with self-checking function, which can confirm whether the motor assembly is working normally before the anastomat is fired.

[0005] The present application is realized by the following technical solutions: A transmission mechanism with self-checking function, which is arranged in the anastomat body of an electric anastomat; The front end of the anastomat body is slidingly installed with a driver, and the driver is connected with an anastomosis assembly provided in the electric anastomat; The transmission mechanism comprises: A rack extending in the front-rear direction; A stroke buffer structure, the rack is matched with the driver through the stroke buffer structure; A motor assembly, which is matched with the rack in transmission and drives the rack to move forward and backward; and A main PCBA board, which divides the running stroke of the rack into at least anastomosis stroke and self-checking stroke in the front-rear direction; Wherein, the rack moves forward and backward in the self-checking stroke, which is used to detect whether the motor assembly is effectively running, and the stroke buffer structure ensures that the driver will not be displaced; when the rack moves forward in the kiss-cutting stroke, the rack drives the driver to move forward through the stroke buffer structure and completes the firing; when the rack retreats to the initial position through the kiss-cutting stroke and the self-checking stroke, it drives the driver and the kiss-cutting assembly to retreat to the initial position.

[0006] Compared with the prior art, the present application has the following advantages: 1. The transmission mechanism with self-checking capability can ensure that the motor assembly can work normally before the kiss-cutting assembly is actually fired, thereby improving safety.

[0007] 2. The transmission mechanism uses the motor output gear to cooperate with the rack for transmission, and the number of rod members of the transmission mechanism is small, which effectively reduces the influence of friction and motion interference between the rod members on transmission efficiency, thereby ensuring high transmission efficiency and stability.

[0008] 3. The transmission mechanism is simple in composition, small in parts, small in quantity, and small in occupied space, which is beneficial to miniaturization design of the instrument. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 Effect diagram of the present application in the anastomat body; Figure 2 Matching relationship diagram of part accessories of the present application; Figure 3 Structure diagram of the rack and the stroke self-checking block; Figure 4 Effect diagram of the main PCBA board arranged at the top of the anastomat body; Figure 5 Structure diagram of the rack and the stroke self-checking block; Figure 6 Effect diagram of the main PCBA board arranged at the side of the anastomat body; Figure 7 Disassembly and assembly connection structure diagram of the rack and the stroke self-checking block; Figure 8 Overall structure diagram of the electric anastomat using the transmission mechanism of the present application; Figure 9 Structure diagram of the first embodiment of the driver and the stroke self-checking block; Figure 10 Structure diagram of the second embodiment of the driver and the stroke self-checking block; Figure 11 Structure diagram of the pointer pull hook limiting safety connection pin; Figure 12 Structure diagram of the Figure 11 Local enlarged diagram of the middle pointer pull hook and the safety connection pin; Figure 13 Structure diagram for the structure of the pointer pull hook when the safety connection pin is not limited; Figure 14 For Figure 13 Local enlarged view of the middle pointer pull hook and the safety connection pin.

[0010] Label explanation: 1 external sheath, 2 driver, 21 first connection hole, 22 second empty stroke slot, 3 connection shaft, 4 rack, 401 stroke self-checking block, 411 raised rib, 412 containing groove, 413 first empty stroke slot, 413a front side point, 413b rear side point, 414 channel, 415 second connection hole, 42 insertion slot, 421 insertion block, 5 wire rod, 6 main PCBA board, 61 kiss cutting termination switch, 62 self-checking kiss cutting critical switch, 63 initial switch, 7 anastomat body, 71 firing handle, 8 adjusting nut, 9 rack gland, 10 safety connection pin, 11 stop block, 12 firing button, 13 firing PCBA board, 14 motor assembly, 141 gear, 15 kiss cutting assembly, 16 pointer pull hook, 17 indicating needle, 18 push block, 19 reset spring. DETAILED DESCRIPTION

[0011] The invention will be described in detail below with reference to the accompanying drawings, but the protection scope of the invention is not limited to the following description: As Figures 1 to 14 shown, a transmission mechanism with self-checking function is arranged in the anastomat body 7 of an electric anastomat; The front end of the anastomat body 7 is slidingly installed with a driver 2, and the driver 2 is connected with the kiss cutting assembly provided in the electric anastomat; The transmission mechanism comprises: A rack 4 is arranged to extend in the front-rear direction; A stroke buffering structure, the rack 4 cooperates with the driver 2 through the stroke buffering structure; A motor assembly 14, which cooperates with the rack 4 in transmission and drives the rack 4 to move forward and backward; and A main PCBA board 6, which divides the running stroke of the rack 4 into at least a kiss cutting stroke and a self-checking stroke in the front-rear direction; Among them, when the rack 4 moves forward and backward in the self-checking stroke, it is used to detect whether the motor assembly is effectively running and the stroke buffering structure ensures that the driver 2 will not displace; when the rack 4 moves forward in the kiss cutting stroke, the rack 4 drives the driver 2 to move forward through the stroke buffering structure and completes the firing; when the rack 4 retreats to the initial position through the kiss cutting stroke and the self-checking stroke, it drives the driver 2 and the anastomotic assembly to retreat to the initial position.

[0012] It should be noted that the front end of the stapler body 7 is connected to an outer sheath 1, and the driver 2 is slidably installed inside the outer sheath 1. The outer sheath 1 and the driver 2 are located on the first axis inside the stapler body 7; the rack 4 is located on the second axis inside the stapler body 7, and the first axis and the second axis are parallel.

[0013] like Figure 9 As shown, in the first embodiment of the driver and stroke self-test block: The stroke buffer structure includes a connecting shaft 3 and a first empty stroke groove 413; The connecting shaft 3 is mounted on the driver 2 which has a first connecting hole 21; The first empty travel groove 413 is provided on the rack 4, the connecting shaft 3 passes through the first empty travel groove 413, and the connecting shaft 3 can move back and forth within the first empty travel groove 413.

[0014] Furthermore, a stroke self-test block 401 is provided at the front end of the rack 4; a first empty stroke slot 413 is provided on the stroke self-test block 401; The stroke self-check block 401 is also provided with a protruding rib 411; the stroke self-check block 401 moves with the rack 4, causing the protruding rib 411 to move during the kissing stroke and the self-check stroke; The travel self-test block 401 is provided with a receiving slot 412 for the driver 2 to pass through.

[0015] The first empty stroke groove 413 has a front point 413a and a rear point 413b at its front and rear ends, respectively. When the rack 4 moves back and forth within the self-test stroke, the motor assembly 14 rotates, driving the rack 4 to move forward or backward along the second axis, which in turn drives the stroke self-test block 401 to move forward or backward along the second axis. Due to the effect of the first empty stroke groove 413, the connecting shaft 3 reciprocates between the front point 413a and the rear point 413b of the first empty stroke groove 413. This makes the movement of the rack 4 during this process an empty stroke, used to check whether the motor assembly 14 is working properly. This process cannot drive the driver 2 to move. This empty stroke can be used to observe whether the transmission mechanism is operating normally before the actual firing and cutting engagement, improving safety.

[0016] like Figure 10 As shown, in the second implementation of the driver and stroke self-test block: The stroke buffer structure is a connecting shaft 3 and a second empty stroke groove 22; The connecting shaft 3 is mounted on the rack 4 and has a second connecting hole 415. The second empty travel groove 22 is provided on the driver 2, the connecting shaft 3 passes through the second empty travel groove 22, and the connecting shaft 3 can move back and forth within the second empty travel groove 22.

[0017] Furthermore, the front end of the rack 4 is provided with a stroke self-checking block 401; the second connecting hole 415 is provided on the stroke self-checking block 401 of the rack 4, and the connecting shaft 3 is installed in the second connecting hole 415. The stroke self-check block 401 is also provided with a protruding rib 411; the stroke self-check block 401 moves with the rack 4, causing the protruding rib 411 to move during the kissing stroke and the self-check stroke; The travel self-test block 401 is provided with a receiving slot 412 for the driver 2 to pass through.

[0018] When rack 4 moves back and forth within its self-test stroke, motor assembly 14 rotates, causing rack 4 to move forward or backward along the second axis. This, in turn, causes stroke self-test block 401 to move forward or backward along the second axis. Meanwhile, connecting shaft 3 reciprocates within the second idle stroke groove 22. This idle stroke constitutes an idle stroke for checking whether motor assembly 14 is functioning correctly; it does not drive driver 2. This idle stroke allows observation of whether the transmission mechanism is operating normally before actual firing and cutting, improving safety.

[0019] In the two embodiments above, the axis of the connecting shaft 3 is perpendicular to the first axis and the second axis, respectively.

[0020] It should be noted that, based on embodiments 1 and 2, the main PCBA board 6 is provided with a kissing termination switch 61, a self-test kissing critical switch 62, and an initial switch 63 sequentially from front to back; a kissing stroke is formed between the kissing termination switch 61 and the self-test kissing critical switch 62, and a self-test stroke is formed between the self-test kissing critical switch 62 and the initial switch 63; the stroke self-test block 401 moves with the rack 4, driving the protruding rib 411 to move in the kissing stroke and the self-test stroke. The rear part of the driver 2 extends into the receiving groove 412, and the rear end face of the driver 2 can form a face contact with the inside of the receiving groove 412, using the end face force to achieve a stable and reliable effect, preventing the situation where the driver 2 fails during the secondary firing process, resulting in the inability to perform kissing and cutting.

[0021] like Figures 2 to 4 As shown, the stroke self-test block 401 can be located at the front end of the rack 4, and the protruding rib 411 is located at the top of the stroke self-test block 401; the main PCBA board 6 is located at the top inside the anastomosis device body 7, and is used to cooperate with the stroke self-test block 401 and the protruding rib 411.

[0022] like Figure 5 and Figure 6As shown, the stroke self-test block 401 can be located at the front end of the rack 4, and the protruding rib 411 is located on the side of the stroke self-test block 401; the side of the main PCBA board 6 located inside the anastomosis device body 7 forms a cooperation with the stroke self-test block 401 and the protruding rib 411.

[0023] like Figure 7 As shown, for ease of production and assembly, the stroke self-test block 401 and the rack 4 are produced separately and then assembled, that is, the stroke self-test block 401 is installed on the rack 4 in a disassembled manner; the front end of the rack 4 is provided with a slot 42, and the stroke self-test block 401 is provided with a plug 421 that can be inserted into the slot 42.

[0024] On the other hand, the rack 4 and the stroke self-test block 401 are designed as a detachable structure. If the stroke self-test block 401 or the rack 4 alone has a problem, only one part can be replaced instead of replacing the entire rack 4 and the stroke self-test block 401, which can save costs.

[0025] Furthermore, the motor assembly 14 includes a motor and a gear 141 connected to the motor output shaft, with the gear 141 engaging with the rack 4. The transmission mechanism also includes a firing PCBA board 13, which is located within the firing handle 71 of the anastomosis device body 7. A firing button 12 is also installed on the firing handle 71. The firing PCBA board 13, the motor, and the main PCBA board 6 are connected. Pressing the firing button 12 triggers the firing PCBA board 13, thereby driving the motor. The structure of the motor and gear 141 is a conventional technique and will not be described in detail.

[0026] Furthermore, the stapler body 7 is equipped with a first safety device; The first safety device includes a rack cover 9, a stop block 11, and a safety connecting pin 10; wherein, the rack cover 9 is located on the side of the rack 4 and the gear 141; a safety switch extending out of the anastomosis device body 7 is installed on the rack cover 9; the safety connecting pin 10 is located inside the firing handle 71; the safety switch is connected to the stop block 11 through the safety connecting pin 10; the stop block 11 is located between the firing PCBA board 13 and the firing button 12, and is used to prevent the firing button 12 from contacting the firing PCBA board 13; By toggling the safety switch, the safety connecting pin 10 moves the stop block 11, thereby disengaging the stop block 11 from blocking the firing button 12, allowing the firing button 12 to contact the firing PCBA board 13.

[0027] The stapler body 7 is equipped with a second safety device; The second safety device includes a lead screw 5, an adjusting nut 8, and a pointer hook 16. The adjusting nut 8 is rotatably mounted on the rear end of the stapler body 7, and the lead screw 5 is rotatably mounted inside the stapler body 7, with its rear end extending out of the stapler body 7 and threadedly connected to the adjusting nut 8. The pointer hook 16 is mounted inside the stapler body 7 in a back-to-back sliding manner, and the pointer hook 16 is limitedly connected to the safety connecting pin 10 to prevent the movement of the safety switch and the safety connecting pin 10. The lead screw 5 and the pointer hook 16 work together so that rotating the adjusting nut 8 can move the lead screw 5 backward while simultaneously moving the pointer hook 16 backward, causing the pointer hook 16 to disengage from the limited connection with the safety connecting pin 10.

[0028] It should be noted that the second safety device also includes an indicator needle 17 connected to the pointer hook 16, a push block 18 cooperating with the lead screw 5, and a return spring 19; wherein, the indicator needle 17 extends out of the anastomosis device body 7, and the indicator needle 17 cooperates with the green marking area provided on the outside of the anastomosis device body 7. In the initial state, the indicator needle 17 is not in the green marking area, indicating that the safety switch cannot be turned; rotating the adjusting nut 8 can allow the pointer hook 16 to move the indicator needle 17 to the green marking area, which is used to indicate that the safety switch can be turned; The pointer hook 16 includes a horizontal extension piece and a vertical extension piece vertically connected to the rear end of the horizontal extension piece, so that the pointer hook 16 has an L-shaped structure; the front end of the horizontal extension piece is limitedly connected to the safety connecting pin 10, and the vertical extension piece has a slot for the lead screw 5 to pass through. The push block 18 is fixedly connected to the lead screw 5, and the push block 18 is located on the front side of the vertical extension piece of the pointer hook 16; the return spring 19 is sleeved on the outer periphery of the lead screw 5 and located at the rear end of the vertical extension piece of the pointer hook 16. Rotating the adjusting nut 8 can drive the lead screw 5 and the push block 18 to move backward, so that the push block 18 pushes the pointer hook 16 to move backward and squeezes the return spring 19, thereby causing the pointer hook 16 to disengage from the limiting connection with the safety connecting pin 10; rotating the adjusting nut 8 in the opposite direction can drive the lead screw 5 and the push block 18 to move forward, while the return spring 19 pushes the pointer hook 16 forward, thereby restoring the pointer hook 16 to the limiting connection with the safety connecting pin 10.

[0029] Furthermore, the driver 2 is provided with a connecting hole, through which the driver 2 is connected to the connecting shaft 3. The connecting shaft 3 connects the connecting hole on the driver to the protruding rib 411 on the rack 4 travel self-test block 401, thereby realizing the connection between the driver 2 and the rack 4.

[0030] Furthermore, the transmission mechanism also includes a firing PCBA board 13; the firing PCBA board 13 is connected to the firing button 12 and the motor assembly 14 respectively; the firing PCBA board 13 is triggered by pressing the firing button 12, thereby driving the motor assembly 14 to work.

[0031] In summary, when using it: In any embodiment, after the present invention is powered on, since the safety switch is in the initial state, the motor assembly 14 is working. When the rack 4 moves back and forth within the self-test stroke, the motor assembly 14 rotates, causing the rack 4 to move forward or backward along the second axis. This, in turn, causes the stroke self-test block 401 to move forward or backward along the second axis. Due to the effect of the first empty stroke groove 413, the connecting shaft 3 will only reciprocate between the front point 413a and the rear point 413b of the first empty stroke groove 413 during this process. This makes the movement of the rack 4 during this process an empty stroke, used to check whether the motor assembly 14 is working. After the self-test is completed, the protruding rib 411 on the rack 4 can stop at any position between switches 62 and 63, that is, at any position within the self-test stroke.

[0032] Then, the safety switch is turned on, and the firing button 12 is operated to make the rack 4 move in the cutting stroke. During this process, the connecting shaft 3 abuts against the rear point 413b of the first empty stroke groove 413. The motor assembly 14 rotates and drives the rack 4 to move forward along the second axis, which in turn drives the stroke self-test block 401 to move forward along the second axis. At this time, the stroke self-test block 401 can push the connecting shaft 3 to move forward, which in turn drives the driver 2 to move forward along the first axis in the anastomosis device body 7, so that the protruding rib 411 moves to the cutting termination switch 61 of the main PCBA board 6. The rack 4 drives the driver 2 to move forward through the stroke buffer structure and completes the firing, completing the cutting and anastomosis action. At this time, it can enter the pressure holding state. Finally, the motor assembly 14 can be rotated in the opposite direction by controlling the firing button 12 again (or by setting the program), which will drive the rack 4 and driver 2 to retract. The rack 4 retracts after the kissing stroke and / or self-test stroke, and at the same time drives the driver 2 and the kissing assembly to retract. When the protruding rib 411 returns to the self-test kissing critical switch 62 or the initial switch 63, the motor stops, and the entire firing process is completed.

[0033] Although the present invention has been illustrated and described through specific embodiments and alternative methods, it should be understood that various changes and modifications may be made without departing from the spirit and scope of the invention. Therefore, it should be understood that the present invention is not limited in any sense except by the appended claims and their equivalents.

Claims

1. A transmission mechanism with a self-testing function, characterized in that, The transmission mechanism is arranged in the anastomat body (7) of the electric anastomat; The front end of the anastomat body (7) is slidably installed with a driver (2), and the driver (2) is connected with a kiss-cutting assembly provided on the electric anastomat; The transmission mechanism comprises: A rack (4) extending in the front-rear direction; A stroke buffering structure, the rack (4) cooperating with the driver (2) through the stroke buffering structure; A motor assembly (14) drivingly cooperating with the rack (4) and driving the rack (4) to move forward and backward; and A main PCBA board (6) dividing the running stroke of the rack (4) into at least a kiss-cutting stroke and a self-checking stroke in the front-rear direction; Wherein, when the rack (4) moves forward and backward in the self-checking stroke, the motor assembly is used to detect whether it is effectively running, and the stroke buffering structure ensures that the driver (2) will not be displaced; when the rack (4) moves forward in the kiss-cutting stroke, the rack (4) drives the driver (2) to move forward through the stroke buffering structure and completes the firing; when the rack (4) retreats to the initial position through the kiss-cutting stroke and the self-checking stroke, the driver (2) and the anastomosis assembly are driven to retreat to the initial position.

2. The transmission mechanism with self-checking function according to claim 1, characterized in that: The stroke buffering structure comprises a connecting shaft (3) and a first idle stroke groove (413); The connecting shaft (3) is installed on the first connecting hole (21) provided on the driver (2); The first idle stroke groove (413) is provided on the rack (4), the connecting shaft (3) passes through the first idle stroke groove (413), and the connecting shaft (3) can move forward and backward in the first idle stroke groove (413).

3. The transmission mechanism with self-checking function according to claim 1, characterized in that: The stroke buffering structure comprises a connecting shaft (3) and a second idle stroke groove (22); The connecting shaft (3) is installed on the second connecting hole (415) provided on the rack (4); The second idle stroke groove (22) is provided on the driver (2), the connecting shaft (3) passes through the second idle stroke groove (22), and the connecting shaft (3) can move forward and backward in the second idle stroke groove (22).

4. The transmission mechanism with a self-checking function according to claim 2, characterized in that: The front end of the rack (4) is provided with a stroke self-checking block (401); the first idle stroke groove (413) is provided on the stroke self-checking block (401) of the rack (4); The stroke self-checking block (401) is further provided with a raised rib (411); the stroke self-checking block (401) moves with the rack (4) and drives the raised rib (411) to move in the kiss-cutting stroke and the self-checking stroke; The stroke self-checking block (401) is provided with a containing groove (412) for the driver (2) to pass through.

5. The transmission mechanism with a self-checking function according to claim 3, characterized in that: The front end of the rack (4) is provided with a stroke self-checking block (401); the second connecting hole (415) is provided on the stroke self-checking block (401) of the rack (4), and the connecting shaft (3) is installed in the second connecting hole (415); The stroke self-checking block (401) is further provided with a raised rib (411); the stroke self-checking block (401) moves with the rack (4) and drives the raised rib (411) to move in the kiss-cutting stroke and the self-checking stroke; The stroke self-checking block (401) is provided with a containing groove (412) for the driver (2) to pass through.

6. A transmission mechanism with self-checking function according to claim 4 or 5, characterized in that: The stroke self-checking block (401) is mounted on the rack (4); the front end of the rack (4) is provided with a slot (42), and the stroke self-checking block (401) is provided with an insertion block (421) capable of being inserted into the slot (42).

7. The transmission mechanism with self-checking function according to claim 1, characterized in that: The motor assembly (14) comprises a motor and a gear (141) connected to the output shaft of the motor, and the gear (141) is in transmission cooperation with the rack (4).

8. The transmission mechanism with self-checking function according to claim 7, characterized in that: The transmission mechanism further comprises a firing PCBA board (13) arranged in the firing handle (71) of the anastomat body (7), and a firing button (12) is further arranged on the firing handle (71); the firing PCBA board (13) is connected with the motor and the main PCBA board (6); the firing PCBA board (13) is triggered by pressing the firing button (12), and then the motor is driven to work.

9. A transmission mechanism having a self-checking function according to claim 8, characterized in that: The anastomat body (7) is provided with a first safety device; The first safety device comprises a rack gland (9), a stop block (11) and a safety connecting pin (10); wherein the rack gland (9) is arranged on the side of the rack (4) and the gear (141); the safety switch extending out of the anastomat body (7) is arranged on the rack gland (9); the safety connecting pin (10) is arranged in the firing handle (71); the safety switch is connected with the stop block (11) through the safety connecting pin (10); the stop block (11) is arranged between the firing PCBA board (13) and the firing button (12), and is used for blocking the firing button (12) from contacting the firing PCBA board (13); By rotating the safety switch, the safety connecting pin (10) drives the stop block (11) to move, and then the stop block (11) is separated from the blocking of the firing button (12), so that the firing button (12) can contact the firing PCBA board (13).

10. The transmission mechanism with self-checking function according to claim 9, characterized in that: The anastomat body (7) is provided with a second safety device; The second safety device comprises a lead screw (5), an adjusting nut (8) and a pointer pull hook (16); the adjusting nut (8) is rotatably arranged at the rear end of the anastomat body (7), the lead screw (5) is rotatably arranged in the anastomat body (7), and the rear end of the lead screw (5) extends out of the anastomat body (7) and is threadedly connected with the adjusting nut (8); the pointer pull hook (16) is slidably arranged in the anastomat body (7) in the front-rear direction, and the pointer pull hook (16) is limitingly connected with the safety connecting pin (10) to block the movement of the safety switch and the safety connecting pin (10); the lead screw (5) is in linkage cooperation with the pointer pull hook (16), so that the lead screw (5) is driven to move backward and the pointer pull hook (16) is driven to move backward at the same time by rotating the adjusting nut (8), and the pointer pull hook (16) is separated from the limiting connection with the safety connecting pin (10).

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