A cross type nail holding wrench

Abstract

The utility model discloses a kind of cross type nail holding wrench, belong to medical instrument technical field, mainly solve the drawbacks of not holding nail, tool itself is not clean, the wrench is improved to realize self-holding function by head cross structure, including central cylindrical boss and four symmetrical sheet, two sheet are equipped with 0.1mm micro-offset edge, and there is 5.71 ° inclined edge and R2 circular arc transition edge.Utilize the design of micro-offset and cut oblique edge, realize asymmetric distribution, utilize the phenomenon of slightly asymmetric offset to realize self locking.This design omits inner and outer sleeve, utilizes elastic deformation and angle guide to realize screw clamping, with the advantages of simple structure, anti-jamming, easy cleaning, suitable for installation and disassembly of lamina nail in lamina fixation operation.

Description

Technical Field

[0001] This utility model belongs to the field of medical device technology, specifically relating to a tool for holding and fixing lamina screws during laminectomy. This tool is a cross-shaped screw-holding wrench that achieves self-holding effect through structural improvement. Background Technology

[0002] Spinal diseases are common in clinical practice. With the development of minimally invasive surgical techniques, minimally invasive spinal surgery is increasingly widely used in the treatment of spinal diseases due to its advantages such as less trauma and faster recovery. Laminectomy is a common procedure in spinal surgery. During the operation, special tools are needed to hold and install the lamina screws. The efficiency and stability of the screw-holding wrench directly affect the progress and safety of the operation.

[0003] Currently, the main components of laminectomy fixation surgery consist of a cross wrench, a handle, an inner sleeve, and an outer sleeve. Its working principle is as follows: the cross wrench is inserted into the cross-shaped opening of the laminectomy screw; the elastic deformation of the inner sleeve holds the cross head of the screw in place; and then the outer sleeve contracts to clamp the screw, thus achieving the holding and fixation of the laminectomy screw. However, this structure has the following drawbacks:

[0004] Complex processing: The inner and outer sleeves require high precision in processing, resulting in a low yield rate;

[0005] Operational jamming: The inner and outer sleeves are prone to "sticking" due to friction, making it difficult to push them forward;

[0006] Clamping defect: The inner sleeve cannot effectively hold the crosshead of the lamina screw, and it is easy to loosen;

[0007] Difficult to clean: Dirt can easily remain in the gap between the inner and outer sleeves, making it difficult to clean thoroughly.

[0008] Based on the above problems, this utility model proposes a simplified structure that does not require inner and outer sleeves, and achieves a self-supporting effect through head geometry design. Utility Model Content

[0009] The purpose of this improvement is to solve the problems of complex structure, easy jamming, weak clamping and inconvenient cleaning in the existing technology. This utility model provides a cross-shaped nail wrench that achieves self-holding function through micro-offset and bevel angle design, omitting inner and outer tubes, simplifying the structure and improving operational reliability.

[0010] To achieve the above objectives, this utility model provides the following technical solution:

[0011] A cross-shaped nail wrench consists of a handle 1 and a cross-shaped wrench shaft 2. The cross-shaped wrench shaft 2 is characterized by being a cylindrical shaft with a self-holding structure at its head. At the center of the shaft is a cylindrical boss measuring 0.7 × 0.3 mm. Four plates are evenly distributed at the base of the boss, forming a cross shape. Two of these plates are symmetrical, each 0.5 mm wide, and are symmetrically distributed along the center line of the boss. On the other two symmetrical sides of the boss, a 1.1 mm inclined edge is milled outwards at a 5.71° angle, starting 0.1 mm from the base of the boss, and then transitions to the outer diameter of the wrench shaft with an arc of R2. The other side of these two plates is a straight line, passing through the center line of the boss by 0.15 mm. Therefore, the initial thickness of this plate is 0.4 mm, gradually increasing to 0.62 mm, and deviating from the center line of the boss by 0.1 mm.

[0012] Preferably, the cross wrench lever 2 is an integrally formed structure, and the material is stainless steel (1RK91) with high strength and toughness.

[0013] Working principle:

[0014] The laminar nail head has 0.5mm wide, evenly distributed cross grooves, with a 0.4mm deep, 0.8mm diameter circular hole in the center that mates with the boss on the head of the cross wrench. When the head of the cross wrench is placed into the laminar nail groove, the slight offset edge (0.1mm deviation) and the inclined edge (5.71° angle) work together to produce radial elastic offset. The inclined edge guides the plate into the sidewall of the cross groove through angle guidance, achieving self-locking. When the wrench is withdrawn, the deformation returns to its original state, and the plate automatically disengages from the cross groove. The width of the cross groove of the laminar nail... The four plates of the cross wrench lever 2 are evenly distributed around the round hole, with one pair of side plates being... Symmetrically distributed on both sides of the boss, the other pair of side plates are offset from the center of the rod by 0.1mm, but the initial width of the plates is... It compensates for the 0.1mm offset, so when the cross wrench is inserted into the cross groove of the pedicle screw, it is easy to enter. In addition, the increased insertion depth will lock with the 5.71° inclined edge, thus achieving the self-locking function.

[0015] Beneficial effects:

[0016] Simplified structure: Eliminate inner and outer sleeves to reduce processing difficulty and cost;

[0017] Anti-jamming: No sliding parts, avoiding the phenomenon of "grinding and jamming";

[0018] Secure clamping: The micro-offset and tilt angle design enhances the self-locking force;

[0019] Easy to clean: The seamless, one-piece structure makes it easy to clean thoroughly. Attached Figure Description

[0020] Figure 1 A diagram showing the assembly of an old Phillips wrench.

[0021] Figure 2 This is an assembly diagram of the present invention.

[0022] Figure 3 This is a schematic diagram of the cross wrench lever 2 of this utility model.

[0023] Figure 4 This is a schematic diagram of the head A of the cross wrench lever 2 of this utility model.

[0024] Figure 5 This is an enlarged schematic diagram of part B of the head of the cross wrench lever 2 of this utility model. Detailed Implementation

[0025] Material Selection: The cross wrench handle is made of high-strength stainless steel (1RK91), with a hardness of 55HRC after failure treatment. The head is precision milled in one piece. Dimensional Parameters: Cylindrical boss diameter 0.7±0.02mm, height 0.3±0.05mm; mates with the center hole (0.8×0.3) in the cross groove of the conical nail head; the width is defined by the two halves corresponding to a straight line in the cross plate. Furthermore, the initial width of the two halves corresponding to the other straight line in the cross plate is 0.4mm, passing through the center line of the cylindrical boss. As the inclined edge at an angle of 5.71° increases, the width of the plate gradually increases, reaching a maximum of 0.62mm. The plate is offset from the center line of the cylindrical boss by 0.1mm, so there is no dimensional obstruction to the cross groove of the symmetrically distributed conical nail heads. With an eccentricity of 0.1mm, a plate width of 0.4mm can completely enter the groove. However, as the depth increases, the inclined edge will obstruct two sides of the groove, thus achieving a self-holding effect.

[0026] Instructions for use: Align the head of the Phillips head with the Phillips head groove of the lamina screw and insert it. The tilted guide plate will deform and engage in the groove. Then, hold the screw and rotate the wrench handle at the corresponding point to secure it. Finally, gently pull the wrench to release the screw. This method can be repeated, and it remains self-sustaining even with slight wear.

Claims

1. A cross-shaped nail-holding wrench, comprising a handle (1) and a cross-shaped wrench lever (2), characterized in that: The cross wrench handle (2) is a cylindrical handle with a self-holding structure at the head. There is a cylindrical boss with a diameter of 0.7 × 0.3 mm at the center of the handle. Four plates are evenly distributed at the root of the boss, forming a cross shape. Two of them are symmetrical plates with a width of 0.5 mm and are symmetrically distributed through the center line of the boss. On the other two symmetrical sides of the boss, starting from the root of the boss, the plate is recessed by 0.1 mm and tilted outward at an angle of 5.71°. A 1.1 mm inclined edge is milled out and then transitions to the outer diameter of the wrench handle with the R2 arc. The other side of these two plates is a straight line, passing through the center line of the boss by 0.15 mm. Therefore, the initial thickness of this plate is 0.4 mm and gradually increases to 0.62 mm, and it deviates from the center line of the boss by 0.1 mm.

2. The cross-shaped nail-holding wrench according to claim 1, characterized in that: The cross wrench handle (2) is a one-piece molded structure, and the material is stainless steel (1RK91) with high strength and toughness.

Images