Safe disposable blade assembly

Abstract

The utility model discloses a safety type disposable blade assembly. The safety type disposable blade assembly is provided with a blade, a blade seat and a blade protection sleeve. The blade is fixed at the front part of the blade seat; the blade protection sleeve is slidably sleeved on the blade seat along the front-back direction; the blade assembly is assembled and connected with the front part of a knife handle through the rear part of the blade seat; a straight section is arranged on the rear portion of the blade seat, and after the blade assembly is used and the knife handle is separated from the blade assembly, the straight section extends backwards and is exposed out of the blade protection sleeve. A mark which can not be used after being used is added, the straight section is arranged on the rear portion of the blade seat, and after the knife handle is separated from the blade assembly, the straight section extends backwards and is exposed out of the blade protection sleeve, so that obvious difference is formed from the mode before use.

Description

Technical Field

[0001] This utility model relates to medical surgical scalpels, specifically to a safe disposable blade assembly. Background Technology

[0002] Scalpels are essential tools for performing surgical procedures, and their safety is crucial for both the surgeon and the patient. Traditional scalpels consist of a metal handle and a disposable blade attached to the handle before use and removed afterward. However, existing disposable blades lack clear markings after the handle is removed, making it difficult for others to easily determine whether a blade has been used.

[0003] Chinese patent CN102835992B discloses a "Disposable Surgical Blade Assembly and Matching Non-Disposable Handle," which was applied for by the applicant in 2012. While this patent eliminates the possibility of reusing the combination of the blade assembly and handle in the scalpel, achieving the safety objective of single-use blade assembly, the lack of a post-use marking on the blade assembly when the handle is removed after use means that if someone forcibly inserts the handle into the blade holder, the second locking protrusion of the unlock button on the top surface of the blade protector may be damaged, potentially pushing the blade out of the protector and allowing for reuse.

[0004] Therefore, how to overcome the shortcomings of the existing technology mentioned above has become the subject of this utility model. Summary of the Invention

[0005] The purpose of this invention is to provide a safe disposable blade assembly.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A safety-type disposable blade assembly includes a blade, a blade holder, and a blade protective sleeve. The blade is fixed to the front of the blade holder, and the blade protective sleeve is slidably fitted onto the blade holder in a front-to-back direction. The blade assembly is connected to the front of a knife handle via the rear of the blade holder.

[0008] The rear of the blade holder is provided with a straight section. After the blade assembly is used up and the handle is separated from the blade assembly, the straight section extends backward and is exposed outside the blade protective sleeve.

[0009] In the above scheme, the blade assembly is defined to have an initial state, a usage state, and a usage-completed state;

[0010] In both the initial state and the used-out state, the blade and the blade holder are positioned within the blade protective sleeve.

[0011] Before use, insert the handle into the rear end of the blade holder and push the blade holder forward within the blade protector until the blade extends beyond the front of the protector. In the usage state, the blade remains extended beyond the protector.

[0012] In the used-out state, the handle separates from the blade assembly, and the straight section of the blade holder in the blade assembly extends out of the blade protective sleeve.

[0013] A further technical solution is provided, wherein a first elastic arm is connected to the blade holder, and a first protrusion is provided on the first elastic arm; a first limiting part is provided on the blade protective sleeve corresponding to the first protrusion, and a first locking is formed by limiting the first protrusion through the first limiting part;

[0014] A second elastic arm is connected to the blade protective sleeve, and a second protrusion is provided on the second elastic arm facing the blade holder; a second limiting part is provided on the blade holder corresponding to the second protrusion, and the second limiting part limits the second protrusion to form a second lock;

[0015] The second elastic arm is located above the first elastic arm; when unlocking, the second elastic arm is pressed down to deform it, and at the same time the second elastic arm acts on the first elastic arm to deform it together; when the two elastic arms are deformed, the first protrusion and the second protrusion are respectively offset from their corresponding limiting parts, thereby simultaneously releasing the first lock and the second lock.

[0016] In a further technical solution, the second elastic arm is also provided with a limiting stop surface corresponding to the first elastic arm; after the tool handle is removed after use, the first elastic arm is limited by the limiting stop surface.

[0017] A further technical solution is that a second positioning hole is formed on the blade protective sleeve;

[0018] A third elastic arm is connected to the blade holder, and a third protrusion is provided on the third elastic arm facing the blade protective sleeve.

[0019] In the initial state, the third protrusion extends into the second positioning hole to achieve locking.

[0020] In a further technical solution, the second positioning hole is a strip-shaped hole; in the initial assembly state of the blade assembly, the third protrusion extends into the front end of the second positioning hole to achieve locking; after use and removal of the blade handle, the third protrusion slides to the rear end of the second positioning hole and is limited.

[0021] A further technical solution is provided in the rear of the blade holder, which is provided with a fourth elastic arm that extends backward and is used to connect to the blade handle. The end of the fourth elastic arm is provided with a locking block for engaging with the front of the blade handle and a protruding block for preventing the fourth elastic arm from bending and deforming. The protruding block extends toward the inner wall of the blade protective sleeve, and a reserved hole is provided on the inner wall of the blade protective sleeve corresponding to the protruding block.

[0022] In the initial state of the blade assembly, the protruding block faces the pre-drilled hole. When the blade holder is inserted into the blade assembly and connected to the blade holder, the front end of the blade holder acts on the locking block, forcing the fourth elastic arm to bend and deform, while simultaneously forcing the protruding block to extend into the pre-drilled hole for lateral clearance. After the front end of the blade holder passes the locking block, the fourth elastic arm automatically resets due to its elasticity. At this time, the front end of the blade holder engages with the locking block, connecting the blade holder to the blade holder. When the blade holder is pulled out, the front end of the blade holder drives the blade holder to move backward relative to the blade protective sleeve through the locking block, forcing the protruding block to misalign with the pre-drilled hole. In this state, because the protruding block cannot make lateral clearance through the pre-drilled hole, the blade holder cannot be inserted into the blade assembly and connected to the blade holder again.

[0023] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence, nor are they intended to limit this case; they are merely used to distinguish components or operations described using the same technical terms.

[0024] The terms "connection" or "positioning" as used in this article can refer to two or more components or devices making direct physical contact with each other, or making indirect physical contact with each other, or to two or more components or devices operating or moving with each other.

[0025] The terms “include,” “including,” and “have” used in this article are all open-ended, meaning they include but are not limited to.

[0026] Unless otherwise specified, the terms used herein generally have their ordinary meaning in the context of the art, the subject matter, and the specific context. Certain terms used to describe this case will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the case.

[0027] The terms “front,” “back,” “up,” “down,” “left,” and “right” used in this article are directional terms. In this case, they are only used to describe the positional relationship between the structures and are not intended to limit the specific direction of the protection scheme or its actual implementation.

[0028] The working principle and advantages of this utility model are as follows:

[0029] I. This utility model adds a marking indicating that it can no longer be used after use. This is achieved by providing a straight section at the rear of the blade holder. After the blade holder is separated from the blade assembly, the straight section extends backward and is exposed outside the blade protective sleeve, creating a clear and obvious difference from before use.

[0030] Second, this utility model is safer, more convenient, and offers a better feel. After use, when the knife handle is removed, the first elastic arm on the blade holder is limited by the limiting stop. At the same time, the third protrusion of the third elastic arm on the blade holder is engaged by the limiting at the rear end of the second positioning hole of the blade protective sleeve. This design further prevents the blade holder from being pulled out during the removal of the knife handle, forming a double safety measure.

[0031] Third, the assembly of this utility model is more convenient and can be automated. The blade holder can be pushed directly into the blade protective sleeve from front to back, and the first and second locking mechanisms quickly achieve positioning; the blade handle can be inserted directly into the blade holder and blade protective sleeve from back to front, achieving quick installation. Attached Figure Description

[0032] Appendix Figure 1 This is a schematic diagram of the structure of the surgical knife in an embodiment of the present invention;

[0033] Appendix Figure 2 This is an exploded view of the surgical scalpel according to an embodiment of the present invention;

[0034] Appendix Figure 3 This is a cross-sectional schematic diagram of the blade assembly according to an embodiment of the present utility model;

[0035] Appendix Figure 4 This is a schematic diagram of the structure of the combination of the blade and the blade holder according to an embodiment of the present invention;

[0036] Appendix Figure 5 This is a cross-sectional schematic diagram of the blade protective sleeve according to an embodiment of the present utility model;

[0037] Appendix Figure 6 This is a schematic diagram of the blade holder in an embodiment of the present utility model (rear view).

[0038] Appendix Figure 7 This is a schematic diagram of the blade protective sleeve in an embodiment of the present utility model (rear view).

[0039] Appendix Figure 8 This is a schematic diagram showing the initial state of an embodiment of the present invention;

[0040] Appendix Figure 9 for Figure 8 Enlarged view of point A in the middle;

[0041] Appendix Figure 10 A schematic diagram illustrating the preparation of use for an embodiment of this utility model;

[0042] Appendix Figure 11 for Figure 10 Enlarged view of point B in the middle;

[0043] Appendix Figure 12 This is a schematic diagram showing the usage state of an embodiment of this utility model;

[0044] Appendix Figure 13 This is a schematic diagram showing the usage state of an embodiment of this utility model;

[0045] Appendix Figure 14 This is a schematic diagram of the knife handle and blade assembly after separation in an embodiment of this utility model.

[0046] In the attached diagrams above:

[0047] 1. Blade holder; 11. First elastic arm; 111. First protrusion; 12. Locking groove; 13. Third elastic arm; 131. Third protrusion; 14. Fourth elastic arm; 141. Locking block; 142. Extending block; 15. Locking groove; 16. Locking block; 17. Straight section;

[0048] 2. Blade;

[0049] 3. Blade protective sleeve; 31. Blocking plane; 32. Second elastic arm; 321. Second protrusion; 322. Limiting stop surface; 33. Second positioning hole; 34. First positioning hole; 35. Reserved hole;

[0050] 4. Knife handle; 5. Fingers. Detailed Implementation

[0051] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0052] Example: The present invention will be clearly described below with illustrations and detailed description. Any person skilled in the art who understands the examples of the present invention can make changes and modifications based on the technology taught in the present invention without departing from the spirit and scope of the present invention.

[0053] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of this work. Singular forms such as “a,” “this,” “this,” “the,” and “the” as used herein also include plural forms.

[0054] See appendix Figures 1-14 As shown, a blade assembly for a safety scalpel includes a blade 2, a blade holder 1, and a blade protective sleeve 3. The blade 2 is fixed to the front of the blade holder 1, and the blade protective sleeve 3 is slidably fitted onto the blade holder 1 in the front-back direction. The blade assembly is connected to the front of a handle 4 via the rear of the blade holder 1.

[0055] The blade assembly is defined to have an initial state, a usage state, and a used state. In both the initial and used states, the blade 2 and the blade holder 1 are positioned within the blade protective sleeve 3. Before use, the handle 4 is inserted into the rear end of the blade holder 1, and the blade holder 1 is pushed forward within the blade protective sleeve 3 until the blade 2 extends beyond the front of the blade protective sleeve 3. In the usage state, the blade 2 remains extended beyond the blade protective sleeve 3.

[0056] like Figure 4 and Figure 14 As shown, the blade holder 1 has a straight section 17 at its rear. In the used state, the handle 4 is separated from the blade assembly, and the straight section 17 extends rearward and is exposed outside the blade protective sleeve 3. This exposed straight section 17 serves as an indication that the scalpel is no longer usable after use, creating a clear and obvious difference from its previous state, so that others can quickly and directly determine whether the disposable blade has been used.

[0057] Preferably, a first elastic arm 11 is connected to the upper rear part of the blade holder 1. The front end of the first elastic arm 11 is suspended, and the rear end is connected to the body of the blade holder 1. A first protrusion 111 is provided on the front end of the first elastic arm 11.

[0058] The blade protective sleeve 3 is provided with a blocking plane 31 corresponding to the first protrusion 111. In the initial assembly state of the blade assembly, the blocking plane 31 abuts against the front of the first protrusion 111 in the sliding direction, thus forming a first lock on the initial state.

[0059] A second elastic arm 32 is connected to the upper rear part of the blade protective sleeve 3 as an unlocking button. The front end of the second elastic arm 32 is suspended, and the rear end is connected to the body of the blade protective sleeve 3. A second protrusion 321 is provided on the second elastic arm 32 facing the blade seat 1. A locking groove 12 is provided on the blade seat 1 corresponding to the second protrusion 321. In the initial state, the second protrusion 321 and the locking groove 12 abut against each other in the sliding direction to limit the movement, thus forming a second lock for the initial state.

[0060] like Figures 8-11 As shown, in the initial state, the second elastic arm 32 is located above the first elastic arm 11; when unlocking, the second elastic arm 32 is pressed down to deform it, and at the same time the second elastic arm 32 acts on the first elastic arm 11 to deform it together.

[0061] When the first elastic arm 11 deforms, the first protrusion 111 is misaligned with the blocking plane 31, thereby making way and releasing the first lock; when the second elastic arm 32 deforms, the second protrusion 321 is misaligned with the locking groove 12, thereby making way and releasing the second lock.

[0062] Preferably, the first limiting part is a blocking plane 31. In the initial assembly state of the blade assembly, the blocking plane 31 abuts against the first protrusion 111 in the sliding direction to form the first lock in the initial state.

[0063] The second limiting part is a locking groove 12; in the initial state, the second protrusion 321 and the locking groove 12 abut against each other in the sliding direction to limit the movement, forming the second lock in the initial state.

[0064] Preferably, the blade protective sleeve 3 has a first positioning hole 34, which is located at the position of the first protrusion 111 when the blade 2 extends out of the blade protective sleeve 3.

[0065] like Figure 7 , Figure 12 As shown, in the use state, the first protrusion 111 extends into the first positioning hole 34, and the first protrusion 111 is held in the first positioning hole 34 by the elasticity of the first elastic arm 11, thereby forming a lock for the use state.

[0066] Preferably, the blade protector 3 has a second positioning hole 33. The blade holder 1 is connected to a third elastic arm 13, and the third elastic arm 13 has a third protrusion 131 protruding towards the blade protector 3. In the initial state, the third protrusion 131 extends into the second positioning hole 33 to achieve locking.

[0067] Specifically, the second positioning hole 33 is a strip-shaped hole; in the initial assembly state of the blade assembly, the third protrusion 131 extends into the front end of the second positioning hole 33 to achieve locking; after use and removal of the blade handle 4, the third protrusion 131 slides to the rear end of the second positioning hole 33 and is limited. With this design, on the one hand, if the second elastic arm 32 fails to limit the movement due to accidental contact during the insertion of the blade handle 4, the third protrusion 131 of the third elastic arm 13 can still play a limiting role; on the other hand, even if the second protrusion 321 on the blade protective sleeve 3 fails due to factors such as violent operation, the third protrusion 131 can prevent the blade holder 1 from being pulled out during the removal of the blade handle 4 by limiting the movement at the rear end of the second positioning hole 33.

[0068] Preferably, the rear of the blade holder 1 is provided with a fourth elastic arm 14 that extends rearward and is used to connect the blade handle 4. The end of the fourth elastic arm 14 is provided with a locking block 141 for engaging with the front of the blade handle 4 and an extension block 142 for preventing the fourth elastic arm 14 from bending and deforming. The extension block 142 extends toward the inner wall of the blade protective sleeve 3, and a pre-drilled hole 35 is provided on the inner wall of the blade protective sleeve 3 corresponding to the extension block 142.

[0069] In the initial state of the blade assembly, the protruding block 142 faces the pre-drilled hole 35. When the blade handle 4 is inserted into the blade assembly and connected to the blade holder 1, the front end of the blade handle 4 acts on the locking block 141, forcing the fourth elastic arm 14 to bend and deform, and simultaneously forcing the protruding block 142 to extend into the pre-drilled hole 35 for lateral clearance. After the front end of the blade handle 4 passes the locking block 141, the fourth elastic arm 14 automatically resets due to elasticity. At this time, the front end of the blade handle 4 engages with the locking block 141, connecting the blade handle 4 to the blade holder 1. When the blade handle 4 is pulled out, the front end of the blade handle 4 drives the blade holder 1 to move backward relative to the blade protective sleeve 3 through the locking block 141, forcing the protruding block 142 to be misaligned with the pre-drilled hole 35. In this state, because the protruding block 142 cannot make lateral clearance through the pre-drilled hole 35, the blade handle 4 cannot be inserted into the blade assembly and connected to the blade holder 1 again.

[0070] Preferably, a locking groove 15 is provided in front of the locking groove 12, and a locking block 16 is provided between the locking groove 15 and the locking groove 12; in use, the second protrusion 321 cooperates with the locking groove 12 and the locking groove 15 to form the following different states:

[0071] a. When the second protrusion 321 is located in the locking groove 12, the blade 2 is stored in the blade protective sleeve 3, and the blade holder 1 and the blade 2 are locked relative to the blade protective sleeve 3;

[0072] b. When the second elastic arm 32 is pressed, the second protrusion 321 on the second elastic arm 32 moves downward and away from the locking groove 12. At the same time, the second elastic arm 32 forces the first elastic arm 11 to deform downward, and the first protrusion 111 moves downward and offsets the blocking plane 31. In this state, the blade protective sleeve 3 is allowed to slide relative to the blade seat 1 and the blade 2.

[0073] c. When the second protrusion 321 passes over the locking block 16 from the locking groove 12 and falls into the locking groove 15, the blade 2 is stored in the blade protective sleeve 3, and the blade seat 1 and the blade 2 enter a locked state relative to the blade protective sleeve 3. At this time, since the second protrusion 321 is located in the locking groove 15, the second elastic arm 32 cannot be deformed again by pressing.

[0074] Preferably, the side of the locking block 16 near the locking groove 12 is an inclined surface, and the side of the locking block 16 near the locking groove 15 is a vertical surface.

[0075] Preferred, such as Figure 9 As shown, the second elastic arm 32 is also provided with a limiting stop 322 corresponding to the first elastic arm 11. After the knife handle 4 is removed, the first elastic arm 11 is limited by the limiting stop 322. This design further prevents the blade holder 1 from being pulled out during the removal of the knife handle 4, and cooperates with the limiting of the third protrusion 131 by the rear end of the second positioning hole 33 to form a double safety.

[0076] The specific connection method between the handle 4 and the blade holder 1 can adopt the scheme disclosed in the prior art. Since it is not the point of invention in this case, it will not be described in detail here.

[0077] The functions achievable by the double elastic arms of blade holder 1 are described below:

[0078] I. Locking Function

[0079] The first protrusion 111 of the first elastic arm 11 cooperates with the blocking plane 31 of the blade protective sleeve 3, so that the blade holder 1 cannot move forward.

[0080] During implementation: Finger 5 presses the second elastic arm 32 of the blade protector 3. As the second elastic arm 32 moves downwards, it presses the first protrusion 111, causing the first elastic arm 111 to rotate counter-clockwise. When the first protrusion 111 passes the blocking plane 31, unlocking is complete. Simultaneously, when finger 5 presses the second elastic arm 32, it causes the second protrusion 321 to rotate counter-clockwise. When it disengages from the locking groove 12 of the blade holder 1, unlocking is complete. After both unlocking points are completed simultaneously, the handle 4 and the blade holder 1 can slide back and forth within the blade protector 3, enabling its use.

[0081] II. Function to prevent the blade holder 1 and the tool shank 4 from separating.

[0082] The first protrusion 111 is inserted into the first positioning hole 34 of the blade protective sleeve 3. During the use of the blade, there will be a pulling action, which can prevent the blade holder 1 from being pulled out due to force and separating from the blade handle 4.

[0083] During implementation: When the blade protector 2 slides backward on the blade holder 1 and the handle 4, the first protrusion 111 engages with the first positioning hole 34, and the blade 2 extends out of the front of the blade protector 3. At this time, the scalpel can be used normally.

[0084] 3. When installing the tool holder 4, it serves as a positioning element, making it easy for the tool holder 4 to be inserted into the blade protector 3 and the blade holder 1.

[0085] When the handle 4 is forcefully inserted into the blade holder 1 and the blade protective sleeve 3, the first protrusion 111 engages with the blocking plane 31, preventing the blade holder 1 from moving forward, thus facilitating the insertion of the handle 4. The third protrusion 131 of the third elastic arm 13 engages with the second positioning hole 33 of the blade protective sleeve 3, which also prevents the blade holder 1 from being unable to move forward, facilitating the insertion of the handle 4.

[0086] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A safety-type disposable blade assembly, the blade assembly having a blade (2), a blade holder (1), and a blade protective sleeve (3), the blade (2) being fixed to the front of the blade holder (1), and the blade protective sleeve (3) being slidably fitted onto the blade holder (1) in a front-rear direction; the blade assembly being assembled and connected to the front of a knife handle (4) through the rear of the blade holder (1); characterized in that: The blade holder (1) has a straight section (17) at the rear. After the blade assembly is used up and the handle (4) is separated from the blade assembly, the straight section (17) extends backward and is exposed to the blade protective sleeve (3).

2. The safety-type disposable blade assembly according to claim 1, characterized in that: A first elastic arm (11) is connected to the blade holder (1), and a first protrusion (111) is protruding on the first elastic arm (11); a first limiting part is provided on the blade protective sleeve (3) corresponding to the first protrusion (111), and the first limiting part limits the first protrusion (111) to form a first lock; A second elastic arm (32) is connected to the blade protective sleeve (3), and a second protrusion (321) is provided on the second elastic arm (32) facing the blade holder (1); a second limiting part is provided on the blade holder (1) corresponding to the second protrusion (321), and a second lock is formed by limiting the second protrusion (321) through the second limiting part; The second elastic arm (32) is located above the first elastic arm (11); when unlocking, the second elastic arm (32) is pressed down to deform it, and at the same time the second elastic arm (32) acts on the first elastic arm (11) to deform it together; when the two elastic arms are deformed, the first protrusion (111) and the second protrusion (321) are respectively offset from their respective limiting parts, thereby simultaneously releasing the first lock and the second lock.

3. A safety-type disposable blade assembly according to claim 2, characterized in that: The second elastic arm (32) is also provided with a limiting stop (322) corresponding to the first elastic arm (11); after the knife handle (4) is taken out after use, the first elastic arm (11) is limited by the limiting stop (322).

4. A safety-type disposable blade assembly according to claim 1, characterized in that: A second positioning hole (33) is opened on the blade protective sleeve (3); A third elastic arm (13) is connected to the blade holder (1), and a third protrusion (131) is provided on the third elastic arm (13) facing the blade protective sleeve (3). In the initial state, the third protrusion (131) extends into the second positioning hole (33) to achieve locking.

5. A safety-type disposable blade assembly according to claim 4, characterized in that: The second positioning hole (33) is a strip-shaped hole; in the initial assembly state of the blade assembly, the third protrusion (131) extends into the front end of the second positioning hole (33) to achieve locking; after the tool holder (4) is removed after use, the third protrusion (131) slides to the rear end of the second positioning hole (33) and is limited.

6. A safety-type disposable blade assembly according to claim 1, characterized in that: The blade holder (1) has a rearwardly extending fourth elastic arm (14) for connecting to the handle (4). The end of the fourth elastic arm (14) is provided with a locking block (141) for engaging with the front of the handle (4) and an extension block (142) for preventing the fourth elastic arm (14) from bending and deforming. The extension block (142) extends toward the inner wall of the blade protective sleeve (3), and a pre-drilled hole (35) is provided on the inner wall of the blade protective sleeve (3) corresponding to the extension block (142). In the initial state of the blade assembly, the protruding block (142) faces the pre-drilled hole (35). When the blade holder (4) is inserted into the blade assembly and connected to the blade holder (1), the front end of the blade holder (4) acts on the locking block (141), forcing the fourth elastic arm (14) to bend and deform, while simultaneously forcing the protruding block (142) to extend into the pre-drilled hole (35) for lateral clearance. After the front end of the blade holder (4) passes the locking block (141), the fourth elastic arm (14) automatically resets due to its elasticity. At this time, the blade holder (4) The front end engages with the locking block (141) to connect the handle (4) to the blade holder (1); when the handle (4) is pulled out, the front end of the handle (4) drives the blade holder (1) to move backward relative to the blade protective sleeve (3) through the locking block (141), forcing the protruding block (142) to misalign with the reserved hole (35). In this state, because the protruding block (142) cannot make lateral clearance through the reserved hole (35), the handle (4) cannot be inserted into the blade assembly and connected to the blade holder (1) again.

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