Self-retracting indwelling catheter to prevent blood leakage

Abstract

A self-retracting indwelling catheter for preventing blood leakage, relating to the area of ​​medical devices, comprises a catheter unit (1) and a needle tube unit (2) on the catheter unit (1), wherein the catheter unit (1) comprises a mounting base (11) and a catheter (12), the catheter (12) being mounted on and passing through the mounting base (11), the needle tube unit (2) comprising a mounting housing (21), a needle tube (22) and a needle holder (23), the needle holder (23) being connected to the needle tube (22), the needle holder (23) being slidably arranged in the mounting housing (21), one end of the needle holder (23) protruding from the mounting housing (21) into the catheter (12), the mounting housing (21) being connected to the mounting base (11), and a locking assembly (3) being arranged on the mounting housing (21).and wherein the locking assembly (3) limits circumferential movement of the mounting housing (21) on the mounting base (11). This invention increases the success rate of indwelling catheter puncture by solving the problem of deviation of the cannula stylet's beveled edge, which leads to a lower success rate.

Description

TECHNICAL AREA

[0001] The present application concerns the field of medical devices, in particular a self-retracting indwelling catheter for the prevention of blood leakage. STATE OF THE ART

[0002] An indwelling catheter, also known as a venous catheter, consists primarily of a flexible catheter / cannula that can remain in the bloodstream and a stainless steel guide needle. During use, the catheter and guide needle are inserted into the blood vessel together. Once the catheter is fully positioned in the blood vessel, the guide needle is withdrawn. Only the flexible catheter remains in the blood vessel, thus enabling the administration of infusions.

[0003] With conventional indwelling catheters, the guide needle connector and the catheter connector are typically fitted directly onto each other to facilitate removal of the guide needle from the catheter. Because these round connectors are fitted directly inside each other, they can easily rotate during use. When the guide needle is inserted into the patient's blood vessel along with the catheter, medical personnel usually hold the catheter connector to hold it in position. This can cause the guide needle to rotate relative to the catheter, inadvertently changing the orientation of the angled tip of the guide needle. This reduces the success rate of indwelling catheter puncture. CONTENT OF THE REGISTRATION

[0004] To increase the success rate of indwelling catheter puncture, the present invention proposes a self-retracting indwelling catheter to prevent blood entry.

[0005] The self-retracting indwelling catheter provided by the registration office to prevent blood entry features the following technical solution: A self-retracting indwelling catheter for preventing blood leakage comprises a catheter unit and a needle tube unit connected to the catheter unit. The catheter unit includes a mounting base, a catheter, and a backflow preventer. The catheter is mounted on the mounting base, the backflow preventer is located within the mounting base, and the backflow preventer is located at one end of the catheter. The needle tube unit comprises a mounting housing, a needle tube, a needle holder, and a retraction assembly. The needle holder is connected to the needle tube and is slidably arranged within the mounting housing. One end of the needle holder extends from the mounting housing into the catheter. The retraction assembly is located on the needle holder and controls the needle holder to move within the mounting housing, thereby retracting the needle tube into the mounting housing.The mounting housing is detachably connected to the mounting base, wherein a locking assembly is arranged on the mounting housing, and wherein the locking assembly limits movement of the mounting housing on the mounting base in the circumferential direction.

[0006] The technical solution described above limits the circumferential movement of the mounting housing on the mounting base when the housing is mounted. Simultaneously, the needle tube exiting the mounting housing enters the mounting base, penetrates the catheter, and finally protrudes from the end of the catheter furthest from the housing. During use, the medical professional inserts the catheter with the needle tube into the patient's skin. Once the catheter and needle tube have advanced into the blood vessel, the needle tube is withdrawn. The locking assembly ensures stable relative positioning between the mounting base and the housing during the insertion process. This maintains a firm relative position of the needle tube to the catheter during insertion, thus reducing patient discomfort and preventing the needle tube from kinking during the procedure.This reduces both the risk of the needle tube penetrating the blood vessels and the risk of the needle tube's cannula bevel tilting during puncture, thus increasing the success rate of indwelling catheter puncture.

[0007] Optionally, the locking assembly comprises several locking lugs, wherein the several locking lugs are arranged on an end wall of the mounting housing, wherein several detent grooves are incorporated in the end wall of the mounting housing, the number of which corresponds to a number of locking lugs, and wherein the locking lugs are inserted into the detent grooves.

[0008] In the technical solution described above, the locking lugs slowly slide into the locking grooves as the mounting housing approaches the mounting base. After the mounting housing and base are fully assembled, the ends of the locking lugs rest against the bottoms of the grooves, while their side walls are secured by the inner walls of the locking grooves. This arrangement prevents any movement of the locking lugs along the circumference of the mounting housing, thus ensuring a stable fit of the mounting housing to the mounting base, virtually eliminating any rotational movement during use. Securing the locking lugs in the locking grooves reduces the risk of the needle tube kinking during puncture and thereby prevents puncture of blood vessels.

[0009] Optionally, a recess is formed in a side wall of the locking lug facing an axis of the mounting housing, wherein the recess leads to an outer circumferential wall of the mounting base, wherein a projection is formed on an inner wall of the locking groove, and wherein the projection is inserted in the recess.

[0010] In the technical solution described above, the projection is inserted into the recess upon contact between the ends of the locking lugs and the bases of the detent slots. The inner wall of the recess is designed to restrict the projection's movement. To remove the projection from the recess, medical personnel must apply a pulling force to the mounting housing, which deforms the locking lugs, causing the projection to eventually emerge from the recess.

[0011] Optionally, the projection has an arc-shaped cross-section, wherein the projection is enveloped by an elastomer bushing, wherein a pressure ridge is formed on an inner wall of the recess, wherein a pressure recess is formed on the elastomer bushing in the direction away from the mounting housing, wherein the elastomer bushing together with the projection is inserted into the recess, and wherein the pressure ridge is inserted into the pressure recess.

[0012] In the technical solution described above, when separating the mounting base from the mounting housing, medical personnel must exert a pulling force on the mounting housing in a direction away from the mounting base. This deforms the locking lugs, and the projection tends to disengage from the recess. Simultaneously, the pressure ridge engaging in the pressure recess acts as a movement limiter for the inner walls of the pressure recess. During the process of the projection disengaging from the recess, the pressure ridge gradually detaches the elastomer bushing from the projection until the projection has completely disengaged from the recess and the elastomer bushing remains in place. The provision of the elastomer bushing ensures a more stable locking of the locking lugs in the detent grooves.

[0013] Optionally, the limiting assembly comprises an arc-shaped connecting tab, a stop, a spring element, and a sliding ring. The arc-shaped connecting tab is arranged at one end of the mounting housing facing the mounting base. The mounting base is enclosed externally by the arc-shaped connecting tab. A connecting groove is formed on an inner wall of the arc-shaped connecting tab, and the stop is slidably arranged in the connecting groove. A connecting bore is formed on an outer wall of the arc-shaped connecting tab. The connecting bore is connected to the connecting groove. One end of the spring element extends into the connecting groove via the connecting bore and is connected to the stop, while the other end of the spring element is connected to the sliding ring. The sliding ring is slidably fitted over the arc-shaped connecting tab.A limiting groove is formed on the outer wall of the mounting base, into which the stop is inserted.

[0014] In the technical solution described above, the arc-shaped connecting tab is initially moved towards the mounting base when the mounting housing is to be assembled with the mounting base, thus gradually increasing the contact area between the arc-shaped connecting tab and the mounting base. When the stop in the connecting groove can touch the outer circumferential wall of the mounting base, the sliding ring is moved towards the connecting bore so that the spring element exerts a tensile force on the stop towards the mounting base. However, the movement of the stop is limited by the outer circumferential wall of the mounting base, therefore the spring element partially bends in the connecting groove.

[0015] When the curved connecting tab completely encloses the mounting housing, the connecting groove and the locking groove align. The stop is released from the outer circumferential wall of the mounting base, and the bent spring element pulls the stop out of the connecting groove. The spring element then easily inserts the stop into the locking groove. The stop is now partially in the locking groove and partially in the connecting groove.

[0016] To separate the mounting base from the mounting housing, medical personnel pull the sliding ring away from the mounting base, allowing the sliding ring to slide along the arcuate connecting tab. This tensions the spring element of the sliding ring, pulling the stop out of the locking groove. When the stop strikes the bottom of the groove, the arcuate connecting tab is separated from the mounting base by the pulling force. This allows the mounting housing to be easily separated from the mounting base.

[0017] The stop interacts with the spring element in such a way that the mounting housing cannot rotate relative to the mounting base during the connection process, thus ensuring a stable connection. Once the stop leaves the limiting groove and contacts the bottom of the connecting groove, the tensile force on the sliding ring is simultaneously applied to separate the mounting base from the mounting housing. This means that a single tensile force can be used to unlock the mounting base via the stop and to separate the mounting base from the mounting housing.

[0018] Optionally, a stop strip is formed on the outer wall of the arc-shaped connecting tab, the stop strip being designed to limit a sliding path of the sliding ring on the arc-shaped connecting tab.

[0019] By applying the technical solution described above, the stop is fully extended from the limiting groove when it reaches the sliding ring on the arcuate connecting tab. A further pulling motion then completely releases the arcuate connecting tab from the mounting base. The arcuate connecting tab prevents overextension of the spring element and simultaneously allows for quick removal of the arcuate connecting tab.

[0020] Optionally, the backflow preventer is connected to the end of the catheter, wherein the backflow preventer is installed in the mounting base, wherein the backflow preventer comprises a rivet insert, a valve insert, and a plastic valve cap, wherein the rivet insert communicates with the end of the catheter in the mounting base, wherein one end of the mounting base facing the mounting housing is provided with a valve groove, wherein the valve insert is inserted into the valve groove and communicates with the rivet insert, wherein the plastic valve cap is attached to one end of the valve insert facing away from the rivet insert, and wherein at least one of the plastic valve cap and the valve insert is arranged to be axially displaceable in the valve groove. The needle tube penetrates the plastic valve cap, the valve insert, the rivet insert, and the catheter sequentially.

[0021] The plastic valve cap deforms, sealing the punctured area created by the needle tube. The medical personnel hold the mounting housing and move it away from the mounting base to remove it. They then insert a Luer connector into the valve groove and slide the plastic valve cap into the groove, ensuring the beveled surface of the valve insert passes through the plastic valve cap and engages with the Luer connector. This connects the catheter to an infusion or blood collection device attached to the Luer connector. The interaction between the plastic valve cap and the valve insert prevents blood from splashing.

[0022] Optionally, the retraction assembly is mounted on the mounting housing so that the needle tube is retracted into the mounting housing, wherein the retraction assembly comprises a spring and a release element for controlling a return of the spring, wherein the spring is mounted on the needle holder, wherein the spring is located between a rear end of the needle holder and the inner end wall of the mounting housing, and wherein the release element is mounted on the mounting housing to control the return of the spring.

[0023] Optionally, the release element comprises a release block connected to the needle holder and a slide switch slidably mounted on the mounting housing, wherein a release opening is formed on the mounting housing, wherein a friction ramp and a straight slide section are formed on an inner wall of the mounting housing along which the release block can slide, and wherein the release opening, the friction ramp and the straight slide section are formed sequentially on the mounting housing and communicate with each other; wherein a release support projection is formed on an inner wall of the release opening, wherein the release block is inserted into the release opening and thereby contacts a side wall of the release support projection, wherein one end of the slide switch rests on the release support projection, and wherein a release projection is provided on a bottom wall of the slide switch facing the release opening.

[0024] In the aforementioned technical solution, once the desired position is reached, the medical personnel push the mounting base forward while simultaneously moving the slide switch toward the base. When the slide switch is no longer in contact with the release support projection, it is depressed, causing the release projection to engage in the release opening and press the release block, thus releasing the release block from being constrained by the release support projection. The release block then moves along the friction ramp under spring force until it reaches the straight slide section. At this point, the needle holder in the retraction channel moves away from the mounting base through the release block, fully retracting the needle tube into the retraction channel.The combination of slide switch and spring allows the needle tube to retract automatically, reducing skipped stitches after the needle tube is pulled out.

[0025] Optionally, an annular groove is formed on the inner wall of the mounting housing, wherein a limiting ring is arranged in the annular groove, wherein an inner diameter of the annular groove is larger than an outer diameter of the limiting ring, wherein a depth of the annular groove is greater than a ring width of the limiting ring, and wherein a locking groove is formed on the outer circumferential wall at one end of the needle holder, which is facing away from the needle tube, into which the limiting ring is inserted.

[0026] By applying the aforementioned technical solution, the limiting ring moves within the annular groove under the guidance of the inclined annular guide surface. The center of the limiting ring gradually approaches the axis of the mounting housing until the limiting ring enters the locking groove along the inclined annular guide surface. Under the force of gravity, the center of the limiting ring moves away from the axis of the mounting housing again. In this state, the inner wall of the upper surface of the limiting ring rests against the bottom of the locking groove, while the side wall of the limiting ring rests against the inner wall of the locking groove. The limiting ring thus prevents the needle holder from moving toward the mounting base. This reduces the risk of the needle holder rebounding due to excessive spring force.

[0027] In summary, the present application exhibits at least one of the following advantageous technical effects. 1. During application, the medical professional inserts the catheter with the needle tube into the patient's skin. Once the catheter and needle tube have advanced into the blood vessel, the needle tube is retracted. At this point, the medical professional triggers the retraction assembly, which automatically retracts the needle tube into the mounting housing, ensuring that the end of the needle tube facing the catheter is fully retracted into the housing. The moment the needle tube separates from the mounting base, the backflow preventer creates a barrier against the blood flowing through the catheter, preventing blood from escaping the mounting base. The locking assembly ensures stable relative positioning between the mounting base and housing during the insertion process.This ensures a stable relative position of the needle tube to the catheter during insertion, thus reducing the patient's pain and preventing the needle tube from kinking during the puncture. This reduces both the risk of the needle tube puncturing blood vessels and the risk of the needle tube's bevel tilting during the puncture, thereby increasing the success rate of indwelling catheter punctures. 2. The stop interacts with the spring element in such a way that the mounting housing cannot rotate relative to the mounting base during the connection process, thus ensuring a stable connection. After the stop leaves the limiting groove and contacts the bottom of the connecting groove, the tensile force on the sliding ring is simultaneously applied to separate the mounting base from the mounting housing. This means that a single tensile force can be used to both unlock the mounting base from the stop and separate the mounting base from the mounting housing. BRIEF DESCRIPTION OF THE DRAWING Fig. Figure 1 is a schematic representation of the structure of the self-retracting indwelling catheter for preventing blood leakage according to an embodiment of the application. Fig. Figure 2 is a schematic vertical section showing the connection relationship between the catheter unit and the needle tube unit in one embodiment of the application. Fig. Figure 3 is a schematic vertical section showing the internal structure of the catheter unit in one embodiment of the application. Fig. Figure 4 is a schematic horizontal section showing the connection between the mounting base and the mounting housing in one embodiment of the application. Fig. Figure 5 is an enlarged view of section A in Fig. 4. Fig. Figure 6 is a schematic vertical section showing the internal structure of the needle tube unit in one embodiment of the application. Fig. Figure 7 is an enlarged view of section B in Fig. 6. Fig. Figure 8 is a representation of the movement sequence of the needle holder according to an embodiment of the application. Fig. Figure 9 is a schematic horizontal section showing the connection between the mounting base and the mounting housing in a further embodiment of the application. Fig. Figure 10 is an enlarged representation of section C in Fig. 9. Fig. Figure 11 is a schematic horizontal section showing the connection between the mounting base and the mounting housing in yet another embodiment of the application. Fig. Figure 12 is an enlarged representation of section D in Fig. 11. DETAILED DESCRIPTION

[0028] Based on the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11 to Fig. Section 12 below explains the present application in more detail.

[0029] The present application discloses a self-retracting indwelling catheter for preventing blood leakage. Design 1

[0030] With reference to Fig. 1 and Fig. The self-retracting indwelling catheter for preventing blood leakage comprises a catheter unit 1, with a needle tube unit 2 connected to one end of the catheter unit 1. The catheter unit 1 includes a mounting base 11 and a catheter 12. The catheter 12 is mounted in the mounting base 11. A non-return valve 13 is arranged at one end of the catheter 12, having been pre-installed in the mounting base 11. A threaded eyelet 116 is integrally formed on the outer wall of one end of the mounting base 11, the end facing away from the catheter 12, and can be connected to a Luer connector.

[0031] The needle tube assembly 2 comprises a mounting housing 21 and a needle tube 22. The mounting housing 21 is detachably connected to the mounting base 11. Gripping lugs 217 are molded onto the outer wall of the mounting housing 21 to allow medical personnel to grasp it. The gripping lugs 217 are arranged on both sides of the axial direction of the mounting housing 21. A needle holder 23 is slidably mounted in the mounting housing 21. The needle holder 23 is connected to one end of the needle tube 22, while the other end of the needle tube 22 protrudes from the mounting housing 21. A retraction assembly 24 is also arranged on the mounting housing 21, which can cause the needle tube 22 protruding from the mounting housing 21 to be completely retracted into the mounting housing 21.

[0032] A locking assembly 3 is arranged at one end of the mounting housing 21. When the mounting housing 21 is mounted on the mounting base 11, the locking assembly 3 prevents the mounting housing 21 from moving circumferentially on the mounting base 11. Simultaneously, the needle tube 22 exiting the mounting housing 21 enters the mounting base 11, penetrates the catheter 12, and finally exits from an end of the catheter 12 that is opposite the mounting housing 21. The distance between the end of the catheter 12 opposite the mounting housing 21 and the base of the bevel of the needle tube 22 is called the "Lai distance." The range of the Lai distance is 0–1 mm, for example, 0.3 ± 0.2 mm. The outer wall of the needle tube 22 rests against the inner wall of the catheter 12.

[0033] During application, the medical personnel insert the catheter 12 with the needle tube 22 through the patient's skin. Once the catheter 12 with the needle tube 22 has advanced into the blood vessel, the medical personnel must withdraw the needle tube 22. In doing so, the medical personnel trigger the retraction assembly 24, which automatically retracts the needle tube 22 into the mounting housing 21. The moment the needle tube 22 detaches from the mounting base 11, the backflow preventer 13 creates a barrier for the blood at the catheter 12, thus preventing blood from leaking from the mounting base 11.

[0034] With reference to Fig. 3 The mounting base 11 has an axially extending flow channel 114 for blood flow. The flow channel 114 extends through the entire mounting base 11. One end of the catheter 12 is inserted into the flow channel 114 of the mounting base 11, while the other end protrudes from the mounting base 11. A rivet groove 115 and a valve groove 113 are also formed sequentially in the axial direction of the flow channel 114.

[0035] A rivet insert 131 is arranged in the rivet groove 115. One end of the rivet insert 131 is funnel-shaped, while the other end is tubular. The funnel-shaped end of the rivet insert 131, with its smaller diameter, is in flow communication with the tubular end. The tubular end of the rivet insert 131 is inserted into the end of the catheter 12 that is positioned in the mounting base 11. The end of the catheter 12 is expanded by the rivet insert 131, meaning that the catheter 12 is in an interference fit with the rivet insert 131. The funnel-shaped end of the rivet insert 131 is located in the rivet groove 115. The inner wall of the rivet groove 115 rests against the funnel-shaped outer wall of the rivet insert 131.

[0036] The valve groove 113 has a larger inner diameter than the rivet groove 115. A valve insert 132 is arranged in the valve groove 113. The end of the valve insert 132 facing the rivet groove 115 is in contact with the inner end wall of the valve groove 113 to ensure the connection between the valve insert 132 and the rivet insert 131.

[0037] The end of the valve insert 132 facing away from the rivet insert 131 has a smaller outer diameter than the inner diameter of the valve groove 113 and is formed with a chamfered surface 1321. A plastic valve cap 133 is fitted onto this end of the valve insert 132 facing away from the rivet insert 131. The material of the plastic valve cap 133 is technically soft and highly elastic. The side of the plastic valve cap 133 facing the valve insert 132 is concavely pressed in. The plastic valve cap 133 is fitted over the end of the valve insert 132. When the plastic valve cap 133 is fitted onto the valve insert 132, the outer circumferential wall of the valve insert 132 lies tightly against the protrusions of the cap opening of the plastic valve cap 133. The outer circumferential wall of the plastic valve cap 133 presses against the inner wall of the valve groove 113 and thereby seals the flow channel 114.

[0038] At least one of the plastic valve cap 133 and the valve insert 132 is arranged to be axially displaceable in the valve groove 113. When the plastic valve cap 133 and the valve insert 132 move relative to each other, the chamfered surface 1321 of the valve insert pierces the plastic valve cap 133, thereby opening the flow channel 114. In this embodiment, the valve insert 132 is fixed in position, while the plastic valve cap 133 can move axially in the valve groove 113.

[0039] With reference to Fig. 1 and Fig. 4. When the mounting housing 21 is inserted into the mounting base 11, the locking assembly 3 assumes a locking function. The locking assembly 3 comprises several locking lugs 31. In this embodiment, there are two locking lugs 31. The two locking lugs 31 are integrally formed on the end wall of the mounting housing 21 and are arranged axially symmetrically around the axis of the mounting housing 21. The gap between the two locking lugs 31 forms a cavity into which the threaded eyelet 116 can be inserted.

[0040] Several locking grooves 111 are machined into the outer circumferential wall of the mounting base 11, which faces the mounting housing 21. The number of locking grooves 111 corresponds to the number of locking lugs 31. In this embodiment, there are two locking grooves 111, and the two locking grooves 111 are arranged axially symmetrically to the axis of the mounting base 11. The locking grooves 111 lead to the end wall of the mounting base 11, which faces the mounting housing 21. The thickness of the locking lug 31 exceeds the depth of the locking groove 111.

[0041] As the mounting housing 21 approaches the mounting base 11, the locking lugs 31 slowly slide into the opening edge of the locking grooves 111. When the mounting housing 21 and mounting base 11 are assembled, each locking lug 31 is clamped between the inner walls of the corresponding locking groove 111. This securely attaches the mounting housing 21 to the mounting base 11 and prevents relative rotation between the mounting base 11 and the mounting housing 21 during use. This reduces the risk of the needle tube 22 bending during puncture, which in turn reduces the likelihood of the needle tube 22 penetrating the blood vessel wall. Furthermore, unwanted rotation of the needle tube 22's bevel during insertion is minimized, ultimately increasing the success rate of the indwelling catheter puncture.

[0042] With reference to Fig. 4 and Fig. 5 A projection 1111 is formed at the base of the locking groove 111. In this embodiment, the projection 1111 is designed as an arcuate rib and is integrally formed at the base of the locking groove 111. A recess 311 is formed in the side wall of the locking lug 31, which points in the direction of the axis of the mounting housing 21. Since the locking lugs 31 are made of plastic and are therefore deformable, when the end of the locking lug 31 abuts the base of the locking groove 111, the projection 1111 is inserted into the recess 311. The inner wall of the recess 311 limits the movement of the projection 1111. To remove the projection 1111 from the recess 311, the medical personnel must exert an external tensile force on the mounting housing 21, which deforms the locking lug 31 and allows the projection 1111 to finally exit the recess 311.

[0043] With reference to Fig. 6. When the medical personnel have completed the puncture and need to retract the needle tube 22, the needle tube 22 is automatically retracted into the mounting housing 21 by means of the retraction assembly 24. A retraction channel 216 is provided in the mounting housing 21. Both the needle holder 23 and the needle tube 22 are arranged in the retraction channel 216 and can move within it in the longitudinal direction of the retraction channel 216. The retraction assembly 24 comprises a spring 241 and a release element 242 for controlling the retraction of the spring 241. The spring 241 is mounted on an end of the needle holder 23 that faces the mounting base 11 and is located within the retraction channel 216; that is, the spring 241 is located between the rear end of the needle holder 23 and the inner end wall of the mounting housing 21 that faces the mounting base 11.When the end of the needle tube 22 emerges from the mounting housing 21, the spring 241 is in a pre-tensioned state, and the two ends of the spring 241 are each in contact with the rear end of the needle holder 23 and the inner end wall of the mounting housing 21.

[0044] Referring to Fig. 6 and Fig. The release element 242 comprises a release block 2421. The release block 2421 is connected to the needle holder 23 via a connecting rod. In its initial state, there is a clearance between the connecting rod and the outer circumferential wall of the needle holder 23. A release opening 211 is formed in the mounting housing 21, the release opening 211 being connected to the retraction channel 216. A release support projection 2111 is integrally formed on the inner wall of the release opening 211, which faces away from the mounting base 11. In this embodiment, the angle between the edges of the release support projection 2111, which faces the release block 2421 and the connecting rod, is defined as angle α. α is an acute angle of less than 90°.

[0045] When the release block 2421 extends from the retraction channel 216, engages in the release opening 211, and abuts the side wall of the release support projection 2111, the spring 241 between the needle holder 23 and the inner end wall of the mounting housing 21 is compressed; that is, the spring 241 is in a compressed state. Assuming the mounting housing 21 is stationary, the compressed spring 241 exerts a spring force that pushes the needle holder 23 away from the mounting base 11. This spring force presses the release block 2421 against the release support projection 2111. In combination with the acute angle α of less than 90° at the release support projection 2111, the self-locking force of the release block 2421 is increased.

[0046] Referring to Fig. 6 and Fig. A slide switch 2422 is slidably mounted on the mounting housing 21. The slide switch 2422 is secured to the mounting housing 21 by an angle bracket, and the slide switch 2422 is connected to this angle bracket via a connecting rod. Part of the slide switch 2422 rests on the release support projection 2111, while a release projection 2423 is integrally formed on the other part of the slide switch 2422, which does not rest on the release support projection 2111. The release projection 2423 and the release opening 211 are fitted with clearance. When the mounting housing 21 is connected to the mounting base 11, the angle bracket connected to the slide switch 2422 rests against the end wall of the mounting base 11, thus preventing the slide switch 2422 from moving.

[0047] After the medical personnel have completed the puncture, they slide the mounting base 11 away from the mounting housing 21 by a distance equal to the length of the release support projection 2111. At this point, the end face of the mounting base 11 moves away from the angle plate connected to the slide switch 2422, thus releasing the locking effect on the slide switch 2422. The medical personnel initially apply a pushing force to the slide switch 2422 away from the release support projection 2111. Once the slide switch 2422 loses the supporting force of the release support projection 2111, the medical personnel continue to push the slide switch 2422 until the release projection 2423 is inserted into the release opening 211, thereby pushing the release block 2421 downwards.This causes the release block 2421 to move along the side wall of the release support projection 2111 in the direction of the retraction channel 216.

[0048] A friction ramp 212 and a straight slide section 213 are formed on the inner wall of the mounting housing 21, along which the release block 2421 can slide. The release opening 211, the friction ramp 212, and the straight slide section 213 are formed sequentially on the mounting housing 21 and are interconnected. When the release block 2421 is located in the friction ramp 212, the connecting rod that links the release block 2421 to the needle holder 23 deforms. During this deformation, the release block 2421 continuously generates sliding friction on the inclined surface of the friction ramp 212. When the release block 2421 is located on the straight slide section 213, the connecting rod returns to its original state due to its own elastic deformation. In this state, there is a clearance between the trigger block 2421 and the straight slide section 213.

[0049] The inclined surface of the friction ramp 212 generates frictional resistance against the movement of the release block 2421. This weakens the thrust of the spring 241 and thus reduces the impact force with which the needle holder 23 strikes the base of the mounting housing 21. Since the thrust of the spring 241 is inversely linearly proportional to the stroke, the thrust of the spring 241 gradually decreases after the acceleration of the needle tube's retraction by the friction ramp 212 is reduced. The straight slide section 213 thereby enables the needle tube 22 to slide frictionlessly.

[0050] With reference to Fig. 6 and Fig. 8. The release block 2421 is guided along the side wall of the release support projection 2111 into the retraction channel 216 after the release block 2421 has been pressed through the release projection 2423. As soon as the release block 2421 is no longer prevented from moving by the release support projection 2111, the spring force of the spring 241 drives the release block 2421 away from the mounting base 11. The thrust of the compressed spring 241 moves the release block 2421 along the friction ramp 212 and further into the area of ​​the straight slide section 213. In doing so, the moving release block 2421 pulls the needle holder 23 in the retraction channel 216 away from the mounting base 11, thereby retracting the exposed needle tube 22 into the retraction channel 216.

[0051] With reference to Fig. A limiting ring 215 is attached to the end of the mounting housing 21, facing away from the mounting base 11. An annular groove 214 is formed on the inner wall of the mounting housing 21 in the area of ​​the limiting ring 215. The inner diameter of the annular groove 214 is larger than the outer diameter of the limiting ring 215, and the depth of the annular groove 214 is greater than the ring width of the limiting ring 215. Due to gravity, the center of the limiting ring 215 and the axis of the mounting housing 21 are not aligned.

[0052] A locking groove 231 is formed on the outer circumferential wall of the needle holder 23 at the end furthest from the mounting base 11. Furthermore, the outer circumferential wall of the needle holder 23 at the end furthest from the mounting base 11 is designed as an inclined annular guide surface 232. As the needle holder 23 moves towards the limiting ring 215, the end with the inclined annular guide surface 232 first penetrates the limiting ring 215. The limiting ring 215 is guided along the inclined annular guide surface 232 in the annular groove 214, with the center of the limiting ring 215 gradually approaching the axis of the mounting housing 21. Finally, the limiting ring 215 slides along the inclined annular guide surface 232 into the locking groove 231. Under the influence of gravity again, the center of the limiting ring 215 moves away from the axis of the mounting housing 21.The inner wall of the limiting ring 215 rests against the base of the locking groove 231 in its upper area, and the side wall of the limiting ring 215 rests against the inner wall of the locking groove 231. This prevents the needle holder 23 from moving towards the mounting base 11, and the spring 241 is in its initial state.

[0053] At the end of the needle holder 23, facing away from the mounting base 11, a cylindrical groove 233 is formed. This cylindrical groove 233 communicates with the needle tube 22, which is mounted in the needle holder 23. A piston 234, made of a gas-permeable but liquid-impermeable material, is inserted into the cylindrical groove 233. The depth of the cylindrical groove 233 is greater than the length of the piston 234. When the piston 234 is inserted into the cylindrical groove 233, a blood observation area remains between the base of the groove 233 and the end face of the piston 234. The needle tube 22 communicates with this blood observation area. If the puncture is successful, blood flows in the inner lumen of the needle tube 22 and enters the blood observation area. The presence or absence of blood in this blood observation area serves to assess whether the indwelling catheter is correctly positioned.

[0054] The operating principle of embodiment 1 is as follows: When the mounting housing 21 is attached to the mounting base 11, the exposed part of the needle tube 22 pierces the plastic valve cap 133, then passes through the valve insert 132, the rivet insert 131 into the catheter 12, and finally exits the catheter 12. During this process, the locking lug 31 is inserted into the locking groove 111. This completes the assembly of the mounting base 11 and the mounting housing 21.

[0055] During application, the medical personnel insert the catheter 12 with the needle tube 22 into the patient's skin. Once the catheter 12 with the needle tube 22 is in a blood vessel, the needle tube 22 must be withdrawn. The medical personnel hold the mounting housing 21 and slide the mounting base 11 away from the mounting housing 21. As this happens, the catheter 12 moves away from the mounting housing 21, while the needle tube 22 remains in its position. The angled plate then leaves the end wall of the mounting base 11. The medical personnel's thumb now pushes the slide switch 2422 towards the mounting base 11. As soon as the slide switch 2422 no longer has contact with the release support projection 2111, the slide switch 2422 is pressed so that the release projection 2423 has penetrated the release opening 211 and presses the release block 2421, causing the release block 2421 to move downwards under pressure.As soon as the release block 2421 is no longer obstructed by the release support projection 2111, the release block 2421 moves under the compressive force of the spring 241 along the friction ramp 212 and further into the straight slide section 213. This causes the needle holder 23 to move away from the mounting base 11 in the retraction channel 216, over the release block 2421, thereby fully retracting the needle tube 22 into the retraction channel 216. The end of the needle holder 23 is inserted into the limiting ring 215, which engages in the locking groove 231. This securely holds the needle tube 22 in the retraction channel 216. Finally, the medical personnel secure the mounting base 11 and pull the arm holding the mounting housing 21 further away from the mounting base 11 to completely separate the mounting housing 21 from the mounting base 11.

[0056] The deformation of the plastic valve cap 133 closes the punctured area created by the needle tube 22. The medical personnel hold the mounting housing 21 and move it away from the mounting base 11 to completely separate them. The medical personnel then insert a Luer connector into the valve groove 113 and slide the plastic valve cap 133 into the groove so that the chamfered surface 1321 of the valve insert 132 passes through the plastic valve cap and connects to the Luer connector, thus connecting the catheter 12 to an infusion or blood collection device attached to the Luer connector.

[0057] The medical personnel first move the mounting base 11 forward a certain distance, creating a gap between the mounting base 11 and the mounting housing 21, thus releasing the movement limit for the slide switch 2422. The slide switch 2422 is then moved axially and subsequently pressed downwards to allow the automatic retraction of the needle tube 22.

[0058] Simultaneously, the elastic deformation of the plastic valve cap 133 prevents blood from escaping after the needle tube 22 is withdrawn. Furthermore, the fit between the locking lug 31 and the locking groove 111 ensures that the mounting base 11 is rotationally fixed relative to the mounting housing 21 during assembly. This prevents the needle tube 22 from rotating relative to the catheter 12 during puncture by medical personnel, thus preventing deviations of the beveled surface during the puncture procedure and increasing the success rate of indwelling catheter puncture. Design 2

[0059] The difference between the present embodiment and embodiment 1 is that the cross-section of the projection 1111 is arc-shaped, as shown in Fig. 9 and Fig. Figure 10 shows that an arc-shaped silicone elastomer bushing 1112 is encased around the projection 1111. The elastomer bushing 1112, together with the projection 1111, can be inserted into the recess 311, with the elastomer bushing 1112 being pressed against the inner wall of the recess 311. A pressing recess 1113 is formed on the elastomer bushing 1112 in the direction away from the mounting housing 21. A pressing groove 3111 is formed in the inner wall of the recess 311, the area of ​​the recess 311 at the pressing groove 3111 being formed with a pressing rib 3112. Once the elastomer bushing 1112, together with the projection 1111, is inserted into the recess 311, the pressing rib 3112 is inserted into the pressing recess 1113.

[0060] The operating principle of embodiment 2 is that, when separating the mounting base 11 from the mounting housing 21, the medical personnel pull the mounting housing 21 away from the mounting base 11 with an external force. During this action, the locking lug 31 deforms, and the projection 1111 tends to disengage from the recess 311. After the pressure rib 3112 is inserted into the pressure recess 1113, the inner wall of the pressure recess 1113 is bounded by the pressure rib 3112. As the projection 1111 gradually moves out of the recess 311, the elastomer bushing 1112 is progressively separated from the projection 1111 by the pressure rib 3112. Ultimately, the projection 1111 moves completely out of the recess 311, while the elastomer bushing 1112 remains in the recess 311. The presence of the elastomer bushing 1112 ensures that the locking lug 31 sits more securely in the detent groove 111. Version 3

[0061] The difference between the present embodiment and embodiment 1 lies in the fact that, with reference to Fig. 11 and Fig. 12, the limiting assembly 3 comprises an arcuate connecting tab 32. The arcuate connecting tab 32 is formed integrally at the end of the mounting housing 21 that faces the mounting base 11. In this embodiment, two arcuate connecting tabs 32 are provided. A clearance is left between the two arcuate connecting tabs 32 to allow the threaded eyelet 116 to slide. When the mounting housing 21 is connected to the mounting base 11, the arcuate connecting tabs 32 engage the mounting base 11 from the outside.

[0062] A connecting groove 321 is formed on the inner wall of the arcuate connecting tab 32. A stop 33 is slidably arranged in the connecting groove 321. The stop moves radially along the arcuate connecting tab 32. In this embodiment, the cross-section of the stop 33 is concave. A connecting bore 322 is formed on the outer wall of the arcuate connecting tab 32 and is connected to the connecting groove 321. The connecting bore 322 is a square opening. The diameter of the connecting bore 322 is smaller than the diameter of the connecting groove 321.

[0063] A spring element 34 is arranged in the connecting bore 322. In this embodiment, the spring element 34 is a leaf spring. One end of the spring element 34 extends into the connecting groove 321 through the connecting bore 322 and is ultimately connected to the side wall of the stop 33. The other end of the spring element 34 extends through the connecting bore 322 and is connected to a sliding ring 35. The sliding ring 35 is fitted over the arcuate connecting tab 32 and can move back and forth along the axis of the arcuate connecting tab 32. The distance between the underside of the sliding ring 35 and the outer circumferential wall of the mounting base 11 is greater than or equal to the height of the threaded eyelet 116. In this embodiment, the distance between the underside of the sliding ring 35 and the outer circumferential wall of the mounting base 11 corresponds exactly to the height of the threaded eyelet 116.

[0064] A stop strip 323 is integrally formed on the outer wall of the arcuate connecting tab 32. The stop strip 323 is designed to limit the sliding path of the sliding ring 35 on the arcuate connecting tab 32. A sliding groove 351 is formed in the side wall of the sliding ring 35 facing the stop strip 323. The sliding groove 351 has a profiled base. The profiled base of the sliding groove 351 in this embodiment is designed as a corrugated surface. Several projections 3231 are formed on the side wall of the stop strip 323 facing the sliding ring 35. When the stop strip 323 engages in the sliding groove 351, these projections 3231 are in contact with the corrugated profiled base of the sliding groove 351.

[0065] A limiting groove 112 is formed on the outer outer wall of the mounting base 11, into which the stop 33 is inserted. The stop 33 is inserted into the limiting groove 112 under the spring force of the spring element 34. The depth of the limiting groove 112 is less than the height of the stop 33. When the sliding ring 35 contacts the stop strip 323, the sliding ring 35 can completely pull the stop 33 out of the limiting groove 112 via the spring element 34.

[0066] The operating principle of embodiment 3 is that the arcuate connecting tab 32 is initially moved towards the mounting base 11 when the mounting housing 21 is to be connected to the mounting base 11. During this process, the contact area between the arcuate connecting tab 32 and the mounting base 11 gradually increases. When the stop 33 in the connecting groove 321 comes into contact with the outer circumferential wall of the mounting base 11, the operator moves the sliding ring 35 towards the connecting bore 322. The spring element 34 then pulls the stop 33 towards the mounting base 11. However, the outer circumferential wall of the mounting base 11 prevents the stop 33 from moving towards the mounting base 11. As a result, the spring element 34 is partially bent into the connecting groove 321.

[0067] When the arc-shaped connecting tab 32 is fully engaged around the mounting housing 21, the connecting groove 321 is precisely aligned with the limiting groove 112. The stop 33 is no longer limited by the outer circumferential wall of the mounting base 11. The deformed spring element 34 exerts a tensile force on the stop 33, which can pull it out of the connecting groove 321. Under the influence of the spring element 34, the stop 33 is smoothly inserted into the limiting groove 112. In this state, part of the stop 33 is located in the limiting groove 112, while the other part remains in the connecting groove 321.

[0068] To separate the mounting base 11 from the mounting housing 21, medical personnel can hold the mounting housing 21, press their index finger against the sliding ring 35, and pull the sliding ring 35 away from the mounting base 11. As the sliding ring 35 slides on the arcuate connecting tab 32, it pulls the spring element 34, which in turn pulls the stop 33 out of the limiting groove 112. When the protrusions 3231 contact the profile base of the sliding groove 351, the stop 33 contacts the groove base of the connecting groove 321. Under the pulling force in the direction away from the mounting base 11, the arcuate connecting tab 32 is now completely separated from the mounting base 11, thus completing the separation of the mounting housing 21 and the mounting base 11.

[0069] While the medical personnel hold the sliding ring 35 in place with their index finger and the mounting housing 21 moves away from the mounting base 11 through their arm, the medical personnel's thumb is pressed against the slide switch 2422, moving in the opposite direction to their arm. First, the slide switch 2422 moves towards the mounting base 11 and is then pressed down with the thumb to trigger the retraction of the needle tube 22.

[0070] The stop 33 interacts with the spring element 34 in such a way that the mounting housing 21 cannot rotate relative to the mounting base 11 during the connection process, thus ensuring a stable connection. After the stop 33 leaves the limiting groove 112 and contacts the bottom of the connecting groove 321, the tensile force on the sliding ring 35 is simultaneously applied to separate the mounting base 11 from the mounting housing 21. This tensile force is used to unlock the mounting base 11 via the stop 33 and to separate the mounting base 11 from the mounting housing 21. Simultaneously, the opposing movement of the thumb and arm actuates and depresses the slide switch 2422 to trigger the retraction of the needle tube 22. This opposing movement of the fingers releases the locking mechanism between the mounting base 11 and the mounting housing 21, separating them as the needle tube 22 retracts.

[0071] The above-mentioned embodiments represent preferred embodiments of the present application and do not limit the scope of protection of this application. Therefore, all equivalent modifications relating to the structure, form, or principle of the present application are expressly included within the scope of protection of this application. LIST OF REFERENCE MARKS 1 catheter unit 11 mounting bases 111 Locking groove 1111 lead 1112 Elastomer bushing 1113 Pressure recess 112 Limit groove 113 Valve groove 114 Flow channel 115 rivet nut 116 Threaded eyelet 12 catheters 13 backflow preventers 131 Rivet insert 132 Valve insert 1321 sloping surface 133 Plastic valve cap 2 needle tube unit 21 Mounting housings 211 Trigger breakthrough 2111 Release support projection 212 Friction ramp 213 straight slide section 214 Ring groove 215 Boundary ring 216 Retreat channel 217 Grip nose 22 Needle tube 23 Needle holders 231 Locking groove 232 inclined ring-shaped guide surface 233 Cylinder groove 234 pistons 24 Retraction assembly 241 spring 242 Trigger element 2421 Release block 2422 Slide switch 2423 trigger advantage 3 Locking assembly 31 Locking nose 311 Recess 3111 Pressure groove 3112 Pressure plate 32 arc-shaped connecting tabs 321 Connecting groove 322 Connecting hole 323 Stop bar 3231 elevation 33 attacks 34 Spring element 35 sliding ring 351 Gleitnut

Claims

[1] Self-retracting indwelling catheter for preventing blood leakage, comprising a catheter unit (1) and a needle tube unit (2) connected to the catheter unit (1), characterized by , that the catheter unit (1) comprises a mounting base (11), a catheter (12) and a non-return valve (13), wherein the catheter (12) is mounted on the mounting base (11), wherein the non-return valve (13) is arranged in the mounting base (11), and wherein the non-return valve (13) is arranged at one end of the catheter (12), that the needle tube unit (2) comprises a mounting housing (21), a needle tube (22), a needle holder (23) and a retraction assembly (24), wherein the needle holder (23) is connected to the needle tube (22), wherein the needle holder (23) is slidably arranged in the mounting housing (21), wherein one end of the needle holder (23) extends from the mounting housing (21) into the catheter (12), wherein the retraction assembly (24) is arranged on the needle holder (23) and controls the needle holder (23) to move within the mounting housing (21) so that the needle tube (22) is retracted into the mounting housing (21), and that the mounting housing (21) is detachably connected to the mounting base (11), wherein a locking assembly (3) is arranged on the mounting housing (21), and wherein the locking assembly (3) limits a circumferential movement of the mounting housing (21) on the mounting base (11). [2] Self-retracting indwelling catheter for preventing blood leakage according to claim 1, characterized by , that the locking assembly (3) comprises several locking lugs (31), wherein the several locking lugs (31) are arranged on an end wall of the mounting housing (21), wherein several detent grooves (111) are incorporated in the end wall of the mounting housing (21), the number of which corresponds to a number of locking lugs (31), and wherein the locking lugs (31) are inserted into the detent grooves (111). [3] Self-retracting indwelling catheter for preventing blood leakage according to claim 2, characterized by , that a recess (311) is formed in a side wall of the locking lug 31, which faces an axis of the mounting housing (21), wherein the recess (311) leads to an outer circumferential wall of the mounting base (11), wherein a projection (1111) is formed on an inner wall of the locking groove (111), and wherein the projection (1111) is inserted in the recess (311). [4] Self-retracting indwelling catheter for preventing blood leakage according to claim 3, characterized by , that the projection (1111) has an arc-shaped cross-section, wherein the projection (1111) is enveloped by an elastomer bushing (1112), wherein a pressure rib (3112) is formed on an inner rim of the recess (311), wherein a pressure recess (1113) is formed on the elastomer bushing (1112) in the direction away from the mounting housing (21), wherein the elastomer bushing (1112) together with the projection (1111) is inserted into the recess (311), and wherein the pressure rib (3112) is inserted into the pressure recess (1113). [5] Self-retracting indwelling catheter for preventing blood leakage according to claim 1, characterized by , that the limiting assembly (3) comprises an arcuate connecting tab (32), a stop (33), a spring element (34) and a sliding ring (35), wherein the arcuate connecting tab (32) is arranged at an end of the mounting housing (21) facing the mounting base (11), wherein the mounting base (11) is enclosed from the outside by the arcuate connecting tab (32), wherein a connecting groove (321) is formed on an inner wall of the arcuate connecting tab (32), and wherein the stop (33) is slidably arranged in the connecting groove (321); that a connecting bore (322) is formed on an outer wall of the arc-shaped connecting tab (32), wherein the connecting bore (322) is connected to the connecting groove (321), wherein one end of the spring element (34) extends into the connecting groove (321) via the connecting bore (322) and is connected to the stop (33), while the other end of the spring element (34) is connected to the sliding ring (35), and wherein the sliding ring (35) is slidably fitted over the arc-shaped connecting tab (32); and that a limiting groove (112) is formed on the outer perimeter wall of the mounting base (11), into which the stop (33) is inserted. [6] Self-retracting indwelling catheter for preventing blood leakage according to claim 5, characterized by, that a stop strip (323) is formed on the arc-shaped connecting tab (32), wherein the stop strip (323) is designed to limit a sliding path of the sliding ring (35) on the arc-shaped connecting tab (32). [7] Self-retracting indwelling catheter for preventing blood leakage according to claim 1, characterized bythat the non-return valve (13) is connected to the end of the catheter (12), wherein the non-return valve (13) is installed in the mounting base (11), wherein the non-return valve (13) comprises a rivet insert (131), a valve insert (132) and a plastic valve cap (133), wherein the rivet insert (131) communicates with the end of the catheter (12) in the mounting base (11), wherein an end of the mounting base (11) facing the mounting housing (21) is provided with a valve groove (113), wherein the valve insert (132) is inserted into the valve groove (113) and communicates with the rivet insert (131), wherein the plastic valve cap (133) is attached to an end of the valve insert (132) facing away from the rivet insert (131), and wherein at least one of the The plastic valve cap (133) and the valve insert (132) are arranged to be slidably arranged in the valve groove (113) in the axial direction of the valve groove (113);and wherein the needle tube (22) passes through the plastic valve cap (133), the valve insert (132), the rivet insert (131) and the catheter (12) in succession.; [8] Self-retracting indwelling catheter for preventing blood leakage according to claim 1, characterized by , that the retraction assembly (24) is mounted on the mounting housing (21) so that the needle tube (22) is retracted into the mounting housing (21), wherein the retraction assembly (24) comprises a spring (241) and a release element (242) for controlling a retraction of the spring (241), wherein the spring (241) is mounted on the needle holder (23), wherein the spring (24) is located between a distal end of the needle holder (23) and the inner end wall of the mounting housing (2), and wherein the release element (242) is mounted on the mounting housing (21) for controlling the retraction of the spring (241). [9] Self-retracting indwelling catheter for preventing blood leakage according to claim 1, characterized by, that the release element (242) comprises a release block (2421) which is connected to the needle holder (23) and a slide switch (2422) which is slidably mounted on the mounting housing (21); wherein a release opening (211) is formed on the mounting housing (21), wherein a friction ramp (212) and a straight slide section (213) are formed on an inner wall of the mounting housing (21), along which the release block (2421) can slide, and wherein the release opening (211), the friction ramp (212) and the straight slide section (213) are formed successively on the mounting housing (21) and are in communication with each other; and wherein a release support projection (2111) is formed on an inner wall of the release opening (211), wherein the release block (2421) is inserted into the release opening (211) and thereby contacts a side wall of the release support projection (2111), wherein an end of the slide switch (2422) rests on the release support projection (2111), and wherein a release projection (2423) is provided on a bottom wall of the slide switch (2422) which faces the release opening (211). [10] Self-retracting indwelling catheter for preventing blood leakage according to claim 1, characterized by, that an annular groove (214) is formed on the inner wall of the mounting housing (21), wherein a limiting ring (215) is arranged in the annular groove (214), wherein an inner diameter of the annular groove (214) is larger than an outer diameter of the limiting ring (215), wherein a depth of the annular groove (214) is larger than an annular width of the limiting ring (215), and wherein a locking groove (231) is formed on the outer circumferential wall at an end of the needle holder (23) facing away from the needle tube (22), into which the limiting ring (215) is inserted.

Images