Safety device for an injector
Through the design of pushing components and needle support, the automatic unlocking and retraction of the syringe needle is achieved, solving the problem of insufficient comfort and high cost of existing safety devices, improving safety and convenience of use, and suitable for a variety of syringe types .
Patent Information
- Application Number
- CN202380038058.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-04
- Filing Date
- 2023-04-27
- Publication Date
- 2024-12-13
AI Technical Summary
The safety devices of existing syringes are not comfortable and efficient enough, resulting in increased accidental punctures, while syringes with retractable needles are expensive to produce and sell, which is not common in the market.
Design a safety device that allows the needle to remain in place during drug use and automatically unlock without user intervention by matching the pushing element and needle support, the needle can be retracted into the syringe body to avoid accidental pricks Injury and suitable for traditional prefilled or to be filled syringes.
It realizes safe holding and automatic unlocking of the needle during drug use, reduces the risk of accidental puncture, simplifies the use process, is suitable for a variety of syringe types, and is highly competitive in production costs.
Smart Images
Figure CN119136867A_ABST
Abstract
Description
Technical Field
[0001] The present invention generally relates to the technical field of syringes. More particularly, the present invention relates to a safety device that can be applied to any type of commercially available syringes and a syringe provided with such a safety device. Background Art
[0002] Disease contamination due to accidental sticking with a used needle has a serious impact not only on the subject infected with the disease, but also on society due to the associated substantial health costs. Healthcare professionals are particularly exposed to the risks arising from the use of syringes.
[0003] In order to overcome this disadvantage, and thus prevent accidental punctures and in this way control the spread of pathogens and infectious agents, syringes are provided with various types of safety devices. Such safety devices include, for example, removable needle covers that must be manually manipulated to prevent direct access to the needle tip and syringes with retractable needles.
[0004] However, prior art safety devices have some disadvantages.
[0005] The removable caps that can be attached to conventional syringes are not comfortable and efficient enough, leading to an increase in accidental punctures in some cases. On the other hand, syringes with retractable needles, while effectively solving the problem of accidental punctures, have high production and sales costs, so they are not very common in the market. Summary of the invention
[0006] It is therefore a primary object of the present invention to provide a safety device for a syringe which overcomes or at least limits the disadvantages associated with safety devices of known type.
[0007] More specifically, the main object of the present invention is to provide a safety device for a syringe configured to hold the needle in place during use or administration of a drug contained in the syringe and to allow automatic unlocking of the needle, i.e. without any intervention by the user of the syringe, and thus allow the needle to be retracted by the safety device so that, after administration, the needle ends up in the body of the syringe on which it is mounted. In other words, the user will not need to intervene with his or her hand to disable the syringe needle, thereby preventing the operator from accidentally stabbing him or herself, for example when inserting a cap on the needle before discarding the syringe.
[0008] Another object of the present invention is to provide a universal safety device for syringes that can be applied to conventional pre-filled or ready-to-fill syringes with Luer slip or Luer lock fittings without the aid of an adapter.
[0009] Yet another object of the present invention is to provide a safety device for a syringe which is simple to implement and can be produced at competitive costs.
[0010] Not the last object of the present invention is to provide a safety device for a syringe which is simple and can be used immediately by the user.
[0011] Therefore, in its first aspect, the present invention relates to a safety device for a syringe, the safety device comprising: a connector, which can be connected to the syringe; a body, which is provided with a cavity and can be connected to the connector so as to extend above it; a needle body, which is used to support and accommodate a needle or cannula, wherein the needle body extends longitudinally in the connector and in the body.
[0012] The device also includes a push element and a needle support, which can be coupled to the distal end of the needle body and can be moved inside the connector by the axial thrust of the plunger of the syringe, and the needle support can be coupled to the needle body. The needle support can be operated by the push element between a locked position of the needle body and an unlocked position of the needle body, in which the needle support is inserted between the connector and the needle body, and in which the needle support is released from the connector and from the needle body and is completely accommodated in the cavity of the body, and the needle or cannula can be freely retracted through the body and the connector.
[0013] Preferred aspects of the invention are set out in the dependent claims.
[0014] In a second aspect thereof, the present invention relates to a syringe provided with the safety device mentioned above.
[0015] Due to its particular configuration, the safety device for a syringe according to the invention allows keeping the needle in place during use or administration of the drug contained in the syringe and allows unlocking the needle automatically after administration, ie without any intervention by the user's hand.
[0016] Furthermore, the versatility of the safety device, its geometry which is completely similar to that of a classic hypodermic needle, and therefore its deployment in the longitudinal direction (along the axis of the syringe) and the absence of any kind of lateral obstruction (such as, for example, an encapsulation chamber outside the syringe) are extremely advantageous factors for performing injections safely and without requiring changes in technique and / or injection angles.
[0017] In the following description of the invention and in the appended claims, the term "proximal" will refer to the portion of the component of the safety device facing the needle or cannula, whereas the term "distal" will refer to the portion of the component of the safety device opposite the needle or cannula, i.e. the portion facing the syringe to which the safety device can be connected. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention will be described below with reference to some examples, which are provided by way of non-limiting examples and are illustrated in the accompanying drawings. These drawings illustrate different aspects and embodiments of the present invention, and where appropriate, reference numerals illustrating structures, components, materials and / or similar elements in different drawings are indicated by similar reference numerals.
[0019] Figure 1 is a perspective view of a safety device for a syringe according to a preferred embodiment of the present invention, wherein the needle is covered by a needle cover.
[0020] Figure 2 is similar to Figure 1 A view of a device where the needle is uncovered and ready for use.
[0021] Figure 3 yes Figure 1 Exploded view of the safety device.
[0022] Figure 3A yes Figure 3 The enlarged view of the circled detail in FIG. 1 shows the needle support in its locked state on the needle body.
[0023] Figure 4 yes Figure 1 A longitudinal cross-sectional view of a safety device.
[0024] Figure 5 Mounted on a syringe with a Luer lock fitting Figure 1 A partial cross-sectional view of a safety device of FIG. 1 shows the syringe when administering a product, wherein the plunger of the syringe is close to the safety device.
[0025] Figure 6 Mounted on a syringe with a Luer lock fitting Figure 1 A partial cross-sectional view of a safety device of FIG. 1 , showing the plunger of the syringe abutting against the push element of the safety device.
[0026] Figure 7 Mounted on a syringe with a Luer lock fitting Figure 1 A partial cross-sectional view of a safety device of FIG. 1 , showing the needle support in an unlocked position of the needle body and the needle unlocked and ready to be retracted into the syringe body.
[0027] Figure 8 Mounted on a syringe with a Luer lock fitting Figure 1 A partial cross-sectional view of the safety device of FIG. 1 , showing the needle now retracted and contained in the syringe body. DETAILED DESCRIPTION
[0028] Although the present invention is susceptible to various modifications and alternative configurations, certain preferred embodiments are shown in the accompanying drawings and described in detail below. It must be understood in any case that it is not intended to limit the present invention to the specific embodiments illustrated, but rather, the present invention is intended to cover all modifications, alternatives and equivalent configurations within the scope of the present invention as defined in the claims.
[0029] Unless otherwise stated, the use of "such as," "etc," "or" indicates non-exclusive alternatives without limitation. Unless otherwise stated, the use of "including" means "including but not limited to."
[0030] Reference Figures 1 to 4 , which illustrates a safety device for a syringe according to a preferred embodiment of the present invention.
[0031] The safety device, generally indicated by reference numeral 100 , comprises a connector 3 , a main body 4 , a needle body 5 , a needle or cannula 7 , a needle support 8 and a push element 9 .
[0032] exist Figure 1 In the syringe, the needle or cannula 7 is covered by a needle cover 6, which protects the user (typically a healthcare professional) from needle sticks before using the syringe.
[0033] Preferably, the connector 3, the body 4, the needle body 5, the needle cover 6, the needle support 8 and the push element 9 are made by injection molding of a plastic material such as, for example, medical grade polypropylene (PP), polyethylene (PE) or Pharmalene. The needle or cannula 7 is typically made of stainless steel.
[0034] The needle support 8 is configured so that its geometry can be changed during use. In particular, and as Figure 3A As shown in detail in FIG. 1 , the needle support 8 has the shape of a hollow cylinder and has a longitudinal slit 81. The presence of such a longitudinal slit 81 allows the needle support 8 to assume two different positions, namely the locking position of the needle body 5 (e.g. Figure 4 ) and the unlocked position of the needle body 5 (e.g. Figure 8 ). Moreover, in the locked position of the needle body 5, the longitudinal slit 81 allows greater adhesion of the needle support 8 both to the needle body 5 and to the connector 3, precisely due to the greater circumferential elastic deformation of the needle support 8. The needle support 8 may not be cylindrical but frustoconical with a very small angle at the vertex. The taper may refer to both the inner and outer surfaces of the needle support 8.
[0035] In particular, and as will become clearer later in this specification, in the locked position of the needle body 5, the needle support 8 is fastened around the needle body 5 and is integral with the connector 3, whereby the needle body 5 is locked in place in the safety device 100. In the unlocked position of the needle body 5, the needle support 8 is integral with the body 4, wherein the needle body 5 is released from the needle support 8 and is thus freely retracted through the body 4 and the connector 3 together with the needle or cannula 7, so that the syringe 10 (see e.g. Figure 7 ) ends its stroke inside the body or syringe 12.
[0036] Due to the application of elastic deformation forces (during installation of the device), the needle support 8 can be moved from one position to another and allows the needle support 8 to perform three main functions: in particular to eliminate any degree of freedom of the needle body 5 during injection, to avoid drug leakage and to unlock the needle body 5 at the end of the injection.
[0037] Preferably, the needle support 8 has a chamfer 82 in its proximal end which, as will be better understood hereinafter, facilitates the insertion of the needle support 8 into the body 4 when the safety device 100 mounted on the syringe 10 is in operation.
[0038] like Figure 4 As shown in detail in FIG. 1 , the connector 3 is hollow and has a cylindrical side wall defining a first cavity 31, preferably frustoconical, configured to accommodate the tip 11 of the syringe 10 (see, e.g. Figure 5 Preferably, the connector 3 is also configured to connect to the Luer lock fitting 14 of the syringe 10 (see, for example Figure 5 ). To this end, two diametrically opposed fins 37 extend at the distal end of the connector 3, which is a typical feature of Luer lock fittings.
[0039] At the proximal portion of the connector 3, a second cavity 34 is formed, also preferably frustoconical, having a taper opposite to that of the first cavity 31. The second cavity 34 is configured to house the needle support 8 closed around the central portion 54 of the needle body 5. The two frustoconical cavities 31 and 34 are in communication with each other and are coaxial.
[0040] On the proximal portion of the connector 3 a body 4 is engaged which, once engaged, moves against a shoulder 39 formed in the connector 3 .
[0041] The body 4 preferably has a frustoconical shape and presents an outer surface and an inner surface, both of which are frustoconical and have the same inclination, delimiting by the inner surface an inner cavity 44, also of frustoconical shape. The inner cavity 44 has a diameter slightly greater than that of the needle support 8. Furthermore, the body 4 is closed at the top by a wall 47 having a through hole 48 for the passage of the needle or cannula 7. In particular, the through hole 48 is dimensioned so that the needle or cannula 7 slides freely therein.
[0042] The body 4 also has a hollow inner cylinder 45 for accommodating the needle or cannula 7. In particular, the hollow inner cylinder 45 extends from the upper closing wall 47 of the body 4 into the inner cavity 44, and the length is greater than or equal to the height of the needle support 8. The outer diameter of the hollow inner cylinder 45 is slightly greater than the inner diameter of the needle support 8. Therefore, when the needle support 8 is in the unlocked position of the needle body, in the absence of external force, the needle support is interference-fitted on the hollow inner cylinder 45 of the body 4, and then locked on the hollow inner cylinder 45 and integrated with it.
[0043] As will be described below, when the needle support 8 is in the above-mentioned unlocked position of the needle body 5, the needle or cannula 7 can be freely retracted through the through hole 48 of the body 4 and the connector 3. In other words, and as Figure 6 As illustrated in FIG. 1 , when the needle support 8 is axially pushed toward the hollow inner cylinder 45 of the body 4 by the pushing element 9 (which in turn is driven by the plunger 16 of the syringe 10), the needle support 8 is tightly held connected to the body 4 around the hollow inner cylinder 45 due to the effect of the friction force generated between the outer surface of the hollow inner cylinder 45 and the inner surface of the needle support 8. The chamfer 82 preferably formed in the needle support 8 facilitates the insertion of the needle body 8 into the hollow inner cylinder 45 of the body 4 from the outside.
[0044] Along the longitudinal axis of the safety device 100 is placed the needle body 5 , which is preferably cylindrical in shape.
[0045] like Figure 3A As shown in detail in FIG. 5 , the needle body 5 has a portion 51 with a narrowed cross section at the proximal end, which defines a shoulder 55. At the head end 53 of the proximal portion 51 with a narrowed cross section, glue or adhesive is preferably applied, which helps to keep the needle or cannula 7 assembled in the needle body 5. The outer diameter of the proximal portion 51 with a narrowed cross section is smaller than the inner diameter of the needle support 8, thereby avoiding any interaction between the outer surface of the proximal portion 51 of the needle body 5 with a proximally narrowed cross section and the interior of the needle support 8. The longitudinal channel 52 (at Figure 4 ) connects the barrel 12 of the syringe 10 to the needle or cannula 7 in order to allow the product or drug to pass therethrough during injection.
[0046] Refer again Figure 4 , the push element 9 has an outer surface 92 and a longitudinal channel 91. A portion of the needle body 5 is accommodated in the proximal portion of the longitudinal channel 91. In particular, the outer diameter of the needle body 5 is slightly larger than the diameter of the longitudinal channel 91 so as to allow an integral and sealed connection between the push element 9 and the needle body 5 in the absence of an axial force. Otherwise, i.e. in the presence of an axial force acting on the push element 9, a relative and liquid-tight sliding between the push element 9 and the needle body 5 is allowed. In other words, in the absence of a push force, the needle body 5 and the push element 9 of the safety device 100 are integral with each other, but move relative to each other when an axial force acts on the push element 9 and the needle body 5 is prevented from moving axially.
[0047] The push element 9 also has a transverse through-opening 94 at its distal end, the purpose of which is to allow the passage of drug from the interior of the syringe up to the needle or cannula 7 (from which the drug flows out for injection into the subject) and to allow the passage of air from the interior of the syringe up to the needle or cannula 7 (from which the air flows out) when the safety device 100 is in use, i.e. mounted on the syringe 10, immediately before the injection of the drug, and to allow the passage of air from the interior of the syringe up to the needle or cannula 7 (from which the air flows out). Furthermore, in the case of a prefilled syringe, the transverse through-opening 94 of the push element 9 allows the passage of the drug contained in the barrel 12 of the syringe 10 from the interior of the syringe. Preferably, the transverse through-opening 94 has a rectangular cross-section, but it may also be circular.
[0048] The pusher element 9 finally has a bottom end 95 provided with a coaxial hole 96 which is nothing more than an extension of the longitudinal passage 91. As will be described in detail below, the bottom surface 95 of the pusher element 9 serves as the end-of-travel surface of the plunger 16 of the syringe 10 when the safety device 100 is in use.
[0049] When assembling the safety device 100, and as Figure 4 As can be seen in FIG. 8 , the needle body 5 is positioned inside the needle support 8 such that a proximal portion 51 with a narrowed cross section protrudes upwards from the needle support 8 .
[0050] Applying an axial force on the proximal surface 83 causes the needle support 8 to be inserted into the second truncated conical cavity 34 of the connector 3, whereby the longitudinal slit 81 of the needle support 8 is slightly closed, which is conducive to the existence of lateral and circumferential forces that lock the needle body 5, so that the needle body 5 is actually integrated with the needle support 8 and cooperates with it.
[0051] Still in the assembly stage, the distal portion of the needle body 5 is accommodated in a slightly interference manner in the proximal portion of the longitudinal channel 91 of the push element 9. In the absence of axial force on the push element 9, the interference accommodation of the needle body 5 in the push element 9 causes the two parts to be integral with each other.
[0052] The assembly of the connector 3 , the needle support 8 , the needle body 5 , the cannula 7 , the main body 4 and the push element 9 is completed by the insertion of the needle cover 6 .
[0053] Reference Figures 5 to 8 , the operation of the security device 100 will now be described.
[0054] First, the user (typically a healthcare professional) mounts the safety device 100 on the syringe 10 for administering the drug. If the syringe 10 is prefilled, the drug is already present in the syringe's barrel 12. Otherwise, the drug should be sucked out from the vial (not shown) containing it. To this end, the connector 3 is interference-coupled to the end 11 of the syringe 10. In the case of a syringe with a Luer lock fitting, in this coupling position, the fins 37 of the connector 3 engage the threads of the internal thread 15 of the Luer lock 14.
[0055] Thereafter, the needle cover 6 is removed so that the needle or cannula 7 is in an uncovered state. Figure 5 The installation state of the safety device 100 is shown in FIG. Figure 5 As can be seen in FIG. 1 , when the safety device 100 is mounted on the tip 11 of the syringe 10, the distal portion of the push element 9 extends into the body or barrel 12 of the syringe 10. This operating state is Figure 5 Shown in.
[0056] In this operating configuration, the needle or cannula 7 is fixed, integral with the body 4 and the connector 3. In the event of an axial force being exerted on the needle or cannula 7, for example when inserting the needle into the skin and tissue of a patient, the needle or cannula 7 pushes the needle support 8 by pushing on its inner wall, so as to fit further inside the second cavity 34 of the connector due to the taper of the inner surface of the needle support 8 and the taper of the outer surface of the central portion 54 of the needle body 5, and thus to make the needle body 5 and therefore the needle or cannula 7 even fastened inside the safety device 100. This advantageously increases the reliability of the device 100 (only when it is most needed, i.e. at the time of injecting the drug). Therefore, neither the patient nor the nurse performing the injection will notice any difference with respect to the syringes generally available on the market.
[0057] Once the needle cover 6 is removed, the user presses the plunger 16 of the syringe until the rubber 15 mounted on the head of the plunger 16 contacts the bottom end 95 of the push element 9 of the safety device 100. This operating state is Figure 6 Shown in.
[0058] In the case of a non-prefilled syringe, the needle or cannula 7 is inserted into the vial in order to access the drug contained therein. After the needle or cannula 7 is inserted into the vial, the plunger 16 is retracted, thereby allowing the drug to enter the barrel 12 by passing through the longitudinal hole of the needle or cannula 7 and then through the longitudinal passage 52 of the needle body 5 and the longitudinal passage 91 and hole 96 of the push element 9, respectively. This optional operating step is not illustrated in the drawings.
[0059] Prior to injection, the escape of any air present in the syringe 12 is facilitated by transverse through-openings 94 and holes 96 formed respectively in the distal end 95 of the pusher element 9. The advancement of the plunger 16 inside the syringe 12 actually pushes the air through the openings 94, and thus through the pusher element 9 and the needle or cannula 7.
[0060] The drug is then injected. In this step, the operating configuration of the needle support 8 prevents the needle or cannula 7 from moving along the axis of the syringe 10 during the perforation of the dermis and hinders unwanted drug leakage during the injection. The drug that is not guided into the needle body 5 but dispersed in the connector 3 is actually blocked at the level of the needle support 8.
[0061] At the end of the injection, the rubber 15 of the plunger 16 of the syringe 10 abuts against the bottom end 95 of the push element 9. This operating state is Figure 6 Shown in.
[0062] At this time, and if Figure 7 As can be seen in the drawing, further advancement of the plunger 16 and the associated rubber 15, in addition to allowing injection of any residual drug still present in the syringe 12, also axially pushes the push element 9, thereby causing upward advancement of the needle body 5 integral therewith, until the head end 53 of the needle body 5 moves to mechanically abut against the annular lower surface of the hollow inner cylinder 45. When this happens, further travel of the piston 16 causes further advancement of the push element 9, which in turn pushes the needle support 8, which is released from the needle body 5 (around which the needle support 8 is mounted), thereby moving to the unlocked position of the needle body 5.
[0063] In this unlocked position of the needle body 5, the needle support 8 leaves the second cavity 34 of the connector 3 freely housed in the cavity 44 of the body 4, locked on and integral with the hollow inner cylinder 45. A force in the interval between about 1.5N and about 2.0N is sufficient to bring the plunger 16 to the end of its stroke.
[0064] In such a configuration, the needle support 8 which is no longer subjected to contact force with the connector 3 is integral with the body 4 because it is held stationary by static friction due to the pressing force exerted by the needle support 8 on the outer surface of the hollow inner cylinder 45 .
[0065] At this point, it should be noted that further advancement of the plunger 16 and the unlocking of the needle or cannula 7 thereby results in an imperceptible displacement of the needle or cannula 7 within the patient's body, typically in the order of a few tenths of a millimeter. Such imperceptible displacement stops when the head end 53 of the needle body 5 moves to mechanically abut against the annular lower surface of the hollow inner cylinder 45.
[0066] At the end of the injection, the needle or cannula 7 is withdrawn from the patient.
[0067] During the withdrawal of the needle or cannula 7 from the dermis, the edge 46 of the hollow inner cylinder 45 of the body 4 (at Figure 5 ) acts as a directional mechanical constraint for the needle body 5, allowing the needle or cannula 7 to not remain in the patient's dermis and thus overcome the friction provided by the dermis.
[0068] Once the needle or cannula 7 is withdrawn from the dermis, and by holding the syringe 10 in an upright position with the tip 11 facing upwards, the plunger 16 and the rubber 15 are slid back into the barrel 12. The retraction of the plunger 16 causes the needle or cannula 7, together with the needle body 5 and the push element 9 to which the needle body 5 is connected by friction, to be retracted through the body 4 and connector 3 of the safety device 100, and they then fall by gravity into the interior of the barrel 12 of the syringe 10, thereby enclosing the needle or cannula 7 inside the barrel 12. The encapsulation of the needle or cannula 7 prevents any accidental puncture by the operator. This operating state is Figure 8 Shown in.
[0069] It should also be noted that small imperfections such as burrs or slight geometrical imperfections of components of the safety device do not negatively affect the retraction of the needle 7 , needle body 5 and push element 9 inside the barrel 12 of the syringe 10 .
[0070] Attaching the needle cover 6 seals the safety device 100 and makes the syringe 10 -safety device 100 assembly ready for disposal.
[0071] From the above description, the features and advantages of the safety device of the present invention are obvious. The safety device is simple to use and universal and is suitable for any commercially available syringe with a Luer slip lock or Luer lock end. The cost of realization and assembly is very low. The few constituent elements are actually easy to realize and facilitate installation along a single axis.
[0072] Finally, it is obvious that the safety device thus conceived is susceptible of numerous modifications and variations; moreover, all the details may be replaced by technically equivalent elements. In practice, the materials used, as well as their dimensions, may be of any type according to the technical requirements.
Claims
1. A safety device (100) for a syringe, comprising: - a connector (3) which can be coupled to a syringe (10); - a body (4) provided with a cavity (44) and capable of being coupled to said connector (3) so as to extend above said connector (3); and - a needle body (5) for supporting and housing a needle or cannula (7), said needle body (5) extending longitudinally in said connector (3) and in said body (4); The device (100) further comprises: a pushing element (9) for connecting the distal end of the needle body (5) and being movable inside the connector (3) by the axial thrust of the plunger of the syringe; and a needle support (8) which is connectable to the needle body (5) and is operable between a locking position of the needle body (5) and an unlocking position of the needle body (5) by the pushing element, in which the needle support (8) is inserted between the connector (3) and the needle body (5), and in which the needle support (8) is released from the connector (3) and from the needle body (5) and is completely accommodated in the cavity (44) of the main body (4), and the needle or cannula (7) is freely retractable through the main body (4) and the connector (3).
2. The safety device (100) according to claim 1, wherein: The connector (3) has a first cavity (31) for accommodating the distal end (11) of the syringe (10) and a second cavity (34) for accommodating at least a portion of the needle support (8), the first cavity (31) and the second cavity (34) being connected to each other and coaxial.
3. The safety device (100) according to claim 2, wherein: The first cavity (31) and the second cavity (34) are frustoconical and have opposite tapers.
4. The safety device (100) according to any one of the preceding claims, wherein: The body (4) is closed at the top by a wall (47) from which a hollow inner cylinder (45) extends into the cavity (44) of the body (4), wherein the wall (47) has a hole (48) for the passage of the needle or cannula (7).
5. The safety device (100) according to claim 4, wherein: The needle support (8) has a substantially frustoconical shape and presents an outer surface and an inner surface both of which are frustoconical, as well as a longitudinal slit (81), wherein the inner diameter of the needle support (8) is smaller than the outer diameter of the hollow inner cylinder (45), so that when the needle support (8) is connected to the hollow inner cylinder (45), the needle support (8) is maintained in an appropriate position inside the main body (4) due to the static friction force generated between the needle support (8) and the hollow inner cylinder (45).
6. The safety device (100) according to any one of the preceding claims, wherein: The pushing element (9) has a longitudinal channel (91) for connecting to the distal end of the needle body (5), wherein the longitudinal channel has a diameter smaller than the outer diameter of the needle body (5) so as to allow an integral and sealed connection between the pushing element (9) and the needle body (5) in the absence of axial force.
7. The safety device (100) according to claim 6, wherein: The pushing element (9) further comprises a transverse through opening (94) at its distal end and a bottom end (95), in which a hole (96) is formed for extending the longitudinal channel (91) for passage of medicine or air.
8. The safety device (100) according to any one of the preceding claims, wherein: The needle body (5) has a longitudinal passage (52) and a proximal portion (51) having a narrowed cross-section so as to define a shoulder (55).
9. The safety device (100) according to any one of the preceding claims, wherein: In the locked position of the needle support (8), the needle body (5), the needle or cannula (7) and the push element (9) are integral and fixed between them in all phases of use of the device.
10. The safety device (100) according to any one of the preceding claims, wherein: The needle body (5) has a central portion (54) for coupling the needle support (8) in its locked position, the central portion (54) having a conical outer surface.
11. A syringe (10) comprising a tip (11), a body (12) and a plunger (16) movable longitudinally in the body (12), characterized in that The syringe (10) comprises a safety device (100) according to any of the preceding claims, wherein, when the needle support (8) is in the unlocked position of the needle body (5), the needle body (5) and the push element (9) integral therewith fall into the interior of the body (12) of the syringe (10).