JP2009540875A - Improved syringe - Google Patents

Abstract

A retractable needle safety syringe having a braking mechanism is provided. The braking mechanism is placed at the end of the syringe body of the syringe. The braking mechanism includes a brake member that is movable between a braking position and a release position. In the braking position, the finger of the brake member frictionally engages the outer surface of the plunger shaft of the syringe. The frictional engagement cancels the pulling force that biases the syringe piston toward the retracted position. When the brake member is moved to the release position, the fingers do not press the outer surface of the shaft. In this way, the retraction force moves the piston toward the retraction position and moves the needle and needle holder to the syringe body.

Description

  The present invention relates to a syringe.

  The hypodermic needle is used in the standard principle by medical professionals such as doctors, nurses, and other medical related fields. A typical hypodermic needle has a syringe body with a hollow internal cavity. The piston is slidably mounted in the syringe body and is moved between a distal position and a distal position. The shaft is fixed to the piston and extends through the distal position of the syringe body. The thumb platform is attached to the end of the shaft. The thumb platform is moved toward or away from the distal end of the syringe body to move the piston toward the distal or distal position, respectively. A needle is attached to the tip of the syringe body. The syringe body piston and the syringe body tip define a variable fluid chamber. The variable fluid chamber is filled with fluid medication to be injected into the patient. In a general hypodermic needle, the needle is fixedly engaged with the distal end portion of the syringe body. Also, the piston is positioned anywhere between the end position and the tip position. The user remains in this position because there is no biasing force to release the thumb platform and bias the piston back toward the retracted position.

  In use, hypodermic needles are supplied to medical professionals with no fluid drug filled into the variable fluid chamber. The user moves the piston toward the tip position. The needle of the hypodermic needle is inserted into the fluid drug container. The user moves the fluid drug from the container to the variable fluid chamber by retracting the piston toward the distal position. Since the user releases the thumb platform and there is no biasing force to bias the piston towards the end position, the piston cannot be moved to the end position.

  The medical professional displaces the syringe with the needle pointing upward, taps the outside of the syringe body to drive the bubble toward the needle, and pushes the thumb platform to eject the bubble from the variable fluid chamber. By pushing slightly, the air trapped in the variable fluid chamber is removed. The medical professional releases the thumb platform and the piston is not retracted back toward the end position. The medical professional injects the fluid medicament into the patient by inserting the needle into the patient's skin and moving the piston toward the tip position. When the piston reaches the tip position, fluid medication is injected into the patient and the medical professional removes the needle from the patient. At this point, the needle is contaminated and exposed, and there are health risks for other persons working with medical professionals or syringes. Drug addicts may also use the needle again.

  The risks associated with the spread of blood-borne pathogens via conventional hypodermic needles are significant and have been reported in detail.In recent years, people have seen health risks associated with needle reuse and accidental needle sticks. More and more are recognized. These risks are most prevalent among certain people such as drug addicts, drug users (eg, diabetics), healthcare professionals, and health care providers. In fact, more than 20 blood-borne pathogens have been transmitted by needle reuse and accidental needle sticks, some of which include human immunodeficiency virus (HIV), acquired immune deficiency syndrome (AIDS), hepatitis B, hepatitis C, syphilis, malaria, tuberculosis, and herpes.

In 1997, a study sponsored by the Centers for Disease Control (CDC) found that about 76 percent of needle stick damage could be avoided by the use of safety needles. As a result, the Needle Law has now been introduced in approximately 25 states and the District of Columbia. In practice, this Safety Needle Act has already been enacted in many states, including California, Texas, New Jersey, and Maryland. The Occupational Safety and Health Administration (OSHA) also evaluates the effectiveness of existing controls designed to minimize or eliminate the occupational contamination of employees, and provides more advanced controls. It publishes blood-borne pathogen criteria necessary to review feasibility. In addition, the Food and Drug Administration (FDA) provides guidelines that suggest the unique characteristics of safety syringes in an effort to protect health workers. These are simple to operate and self-explanatory and require little or no additional training for effective use, as well as an integral part of the device. Includes certain safety features. That is, the guideline suggests that the safety function itself cannot be removed and that the use of the safety function is inevitable. (WWW.osha-slc.gov/SLTC/needlestic/safeneed devices / safeneed devices.html; www.seiu.org).

  As a result of the above legislation and bureau guidelines, the development of syringes with a safety needle concept has invested a great deal of time, effort and cost by syringe manufacturers. Currently, there are at least 250 types of safety syringes. However, existing safety syringes are generally criticized for having safety features that are expensive to manufacture and are not an integral part of the safety syringe. Another criticism includes safety syringes that are not economically feasible because the functioning of the safety function is not self-evident and therefore requires additional training to use the device effectively. Furthermore, the safety function of at least one safety syringe is not at all effective to prevent the transmission of blood-derived pathogens due to “reflux” blood contamination.

  Among current safety syringes, safety syringes that use a spring mechanism that automatically retracts the hollow needle after injecting fluid are most common. However, these safety syringes are generally more expensive due to the need to incorporate additional materials into manufacture. Standard or conventional hypodermic needle syringes typically cost 5 to 7 cents per piece. On the other hand, the intermediate cost increase for safety syringes is about 30 cents or more. At first glance, this minimum cost increase does not appear to be significant. However, after considering the thousands if not millions that are used each year, the resulting increase in costs for using more expensive safety syringes is unfortunately excessive.

  Other syringes have been created that avoid some of the additional costs associated with spring mechanism safety syringes. This syringe can be seen in US Pat. No. 6,057,038 and is issued on July 2, 2002, entitled “Automatic Retractable Needle Safety Syringe”. They are seeking to solve the needle sticking problem. As disclosed therein, a safety syringe is configured to automatically retract the needle portion of the syringe into the syringe body using the vacuum state in the syringe, so that after a single use The syringe is not reused and does not lead to accidental piercing.

  As will be appreciated, the syringe of U.S. Patent No. 6,057,059 uses a vacuum condition to apply an automatic retracting force to the needle. Clearly, the syringe includes a plunger and a needle holder (to which the needle is attached) and is configured to frictionally engage the plunger with the needle holder. When engaged with the needle holder, the vacuum condition inside the syringe exerts a retraction force on the plunger, thereby moving the needle holder / needle by the plunger and pulling the plunger toward the syringe itself. After being fully retracted, the needle does not protrude out of the syringe body, and the syringe cannot be reused and does not accidentally pierce the individual.

The retractable safety syringe helps to overcome some of the problems associated with accidental needle sticks and hypodermic needle reuse. However, due to the construction and retracting forces inherent in the vacuum conditions and spring mechanism aspects of these and other similar syringes, syringe users often experience difficulties in their use. In particular, due to vacuum conditions or a spring mechanism that exerts an automatic pulling force on the plunger, the plunger may automatically retract when not desired.

It is an obvious purpose of these syringes to retract the plunger when the needle holder is frictionally engaged with the plunger. However, automatic retraction of the plunger prior to frictional engagement with the needle holder is often very problematic. For example, automatic retraction makes the syringe very difficult to handle between when the fluid is aspirated and when the fluid is emptied. In effect, the user must manually maintain the plunger position by applying a force to counteract the automatic pulling force. Otherwise, the plunger will retract. Retraction of the plunger is an annoying action if the syringe is not inserted into the object. However, the retraction of the plunger while the needle is inserted into the object effectively leads to the suction of fluid from it rather than the intentional injection of fluid into the object. This situation is extremely detrimental and leads to various undesirable consequences.
US Pat. No. 6,413,236

  Thus, the operation is simple and self-evident and includes a safety feature with a hollow needle that automatically and automatically retracts after a single injection but weakens the automatic retraction of the needle prior to completion of use. There is a need for an inexpensive safety syringe that is effective and effective. Furthermore, there is a need in the art for a self-retracting safety syringe that weakens the automatic retraction of the needle during administration of the fluid injected with the needle.

  According to one embodiment of the present invention, the retractable needle safety syringe is provided with a weakened retracting force. The syringe defines an opposing upper and lower syringe body and includes a syringe body including a syringe cavity, a mounting base defining a shaft hole and attached to the upper syringe body, a plunger assembly including a plunger shaft and a piston And the plunger shaft defines upper and lower shaft portions opposed to each other, the plunger shaft is placed through the shaft hole of the syringe cavity, the piston is placed on the lower shaft portion, and the plunger is placed in the syringe body within the syringe body. And a variable vacuum compartment placed between the piston and the mounting base in the syringe cavity, and the variable vacuum compartment from the lower syringe body to the upper syringe body. It acts to supply the retraction force to be directed in a state in which this retraction force increases when the piston moves toward the lower syringe body, and is applied to the upper syringe body. A shaft brake that acts to frictionally engage the plunger shaft to provide first and second frictional forces opposite to the retracting force, and the first frictional force is such that the piston is in the lower syringe body. A ram member that is acted on the plunger shaft prior to reaching and attached to the upper shaft portion and configured to engage the shaft brake when the piston reaches the lower syringe body portion, The brake causes the second friction force to act on the plunger shaft in accordance with the engagement of the ram member with the shaft brake, and the second friction force is smaller than the first friction force. The variable fluid chamber is placed between the piston and the needle in the syringe cavity.

  The first frictional force has an associated first normal force. The second frictional force has an associated second normal force. The shaft brake is substantially separated from the plunger shaft when the ram member is engaged with the shaft brake.

The axle brake defines a body periphery and includes a hole and a bridge. The hole is mounted in the shaft brake and frictionally engages with the plunger shaft. The bridge defines a bridge width and extends radially from the hole toward the outer periphery of the body. The shaft brake causes the second frictional force to act on the plunger shaft as the bridge width increases. The bridge width increases with the engagement of the ram member with the shaft brake. The ram member at least partially divides the bridge to increase the bridge width.

  The shaft brake further includes a release member mounted on the shaft brake. The bridge width increases with the engagement of the ram member with the release member. The release member may be a shoulder projecting upward from an axial brake opposite the syringe body, and the ram member is dimensioned to engage the shoulder when the piston approaches the lower syringe body. Is determined and configured. Bridge width increases with engagement with the shoulder of the shoulder press. The bridge width increases as the bridge is deformed in response to engagement with the shoulder of the shoulder press and continuous movement toward the lower syringe body of the piston.

  The brake body defines the body thickness and the bridge defines the bridge thickness. The bridge thickness is smaller than the body thickness. The bridge acts to deform in response to engagement with the shoulder of the shoulder press. The bridge includes a non-continuous slit that includes a hinge element, and the bridge width increases upon deformation of the hinge element in response to engagement with the shoulder of the shoulder press and continuous movement toward the lower syringe body of the piston. .

  The shaft brake is formed to include a fixing member placed on the shaft brake. The fixing member acts to mechanically couple the shaft brake to the mounting base. The syringe further includes a needle that is removably mounted to the lower syringe body and extends therefrom to the opposite side of the upper syringe body. The piston including the push engages with the needle when the piston reaches the lower syringe body. The piston acts to move the needle into the syringe cavity when a retracting force is applied to the plunger shaft.

  In accordance with another embodiment of the present invention, a method for reducing retraction of a retractable needle safety syringe is provided. The syringe includes a syringe body, a mounting base, a plunger assembly, a variable vacuum compartment, a shaft brake, and a ram member. The syringe body defines opposing upper and lower syringe body portions and includes a syringe cavity. The attachment base defines an axial hole and is attached to the upper syringe body. The plunger assembly includes a plunger shaft and a piston. The plunger shaft defines opposing upper and lower shaft portions. The plunger shaft is provided through the shaft hole of the syringe cavity. The piston is placed on the lower shaft portion. The plunger is slidably engaged with the syringe body within the syringe cavity. A variable vacuum compartment is provided in the syringe cavity between the piston and the mounting base. The variable vacuum compartment acts to supply a pulling force to the plunger shaft directed from the lower syringe body to the upper syringe body in a state where the pulling force increases upon movement of the piston toward the lower syringe body. To do. The shaft brake is attached to the upper syringe body and acts to frictionally engage the plunger shaft to supply first and second frictional forces that oppose the retraction force. The first frictional force is applied to the plunger shaft before the piston reaches the lower syringe body. The ram member is attached to the upper shaft portion and is formed to engage the shaft brake when the piston reaches the lower syringe body portion. The shaft brake applies a second frictional force to the plunger shaft in accordance with the engagement of the ram member with the shaft brake. The second friction force is smaller than the first friction force. The method includes (a) applying a first frictional force that opposes the pulling force to the plunger shaft before the piston reaches the lower syringe body, and (b) engaging the ram member with the shaft brake. And (c) applying a second frictional force that opposes the pulling force to the plunger shaft in accordance with the engagement of the ram member with the shaft brake.

According to another implementation of the method, the axle brake defines a body periphery and includes a hole and a bridge. The hole is provided in the shaft brake and acts to frictionally engage the plunger shaft. The bridge defines a bridge width and extends radially from the hole toward the outer periphery of the body. The shaft brake causes the second frictional force to act on the plunger shaft as the bridge width increases. The bridge width increases with the engagement of the ram member with the shaft brake. Step (b) of the method further includes increasing the bridge width in response to engagement of the ram member with the shaft brake.

According to yet another implementation of the method, step (b) further includes separating the bridge in response to engagement of the ram member with the shaft brake.
According to yet another implementation of the method, the axle brake further includes a shoulder mounted on the axle brake and projecting upwardly from the opposite side of the axle brake syringe body, and the ram member includes the piston. A shoulder press is sized and configured to engage the shoulder when approaching the lower syringe body. The bridge width increases with engagement with the shoulder of the shoulder press. Also, step (b) of the method further includes engaging the shoulder press with the shoulder and deforming the bridge to increase the bridge width.

  According to yet another implementation of the method, the syringe further includes a needle that is removably mounted to the lower syringe body and extends therefrom opposite the upper syringe body. The piston engages with the needle when the piston reaches the lower syringe body. The piston acts to move the needle into the syringe cavity when a retracting force is applied to the plunger shaft. The method also includes the steps of engaging the needle with the indentation and automatically transferring the needle into the syringe cavity.

  According to yet another embodiment of the syringe, the syringe further has a braking mechanism mounted on the distal end of the syringe body. The braking mechanism is attached to the end portion of the main body via the attachment base. The attachment base is fixedly attached to the end of the main body. A braking mechanism including a cover and a split brake member is provided in the mounting base. That is, the mounting base has a through-hole through which the plunger shaft is slidably moved or placed. The mounting base defines an internal cavity having an upper stage and a lower stage. The upper stage has an inner surface with an inner diameter that is greater than the inner diameter of the lower inner surface. The edge connects the upper and lower stages.

  The cover is inserted into the internal space of the mounting base. That is, the outer surface of the cover is sized and configured to match the upper inner surface. The inner diameter of the inner surface of the cover is smaller than the inner diameter of the lower stage. The split brake member is placed in the cover. When the split brake member is placed in the cover, the fingers of the split brake member press the outer surface of the shaft and frictionally engage the outer surface of the shaft. To release the brake mechanism, the split brake member is moved from the brake position to the release position. The release position is when the split brake member is placed in the second stage of the mounting base. When the split brake member is moved to the release position, the split brake member is expanded away. As such, the fingers of the brake member do not frictionally engage the outer surface of the plunger shaft. Thus, the pulling force that biases the piston back toward the retracted position moves the piston to the retracted position.

  The split brake member is moved from the braking position to the release position by the ram. A ram is formed at the distal end of the plunger. When the piston is moved to the engaged position, the ram initially contacts the top surface of the split brake member. As the piston is further moved toward the engaged position, the ram displaces the brake member to the second stage of the mounting base.

  In one aspect of the brake member, the brake member may have various other configurations. By way of example and not limitation, the brake member may be an integral member with a single split on one side and an integral hinge on the opposite side. Alternatively, the brake member may be an integral member without a single split on one side and an integral hinge on the opposite side. Further, in another alternative, the brake member may be an integral member that does not have a split. In addition, the brake member may have a plurality of protrusions and a base.

  Illustrative and presently preferred embodiments of the invention are illustrated in the accompanying drawings.

  Referring now to the drawings, the illustrations are only for the purpose of illustrating preferred embodiments of the invention and are not intended to limit the invention. FIG. 1 is a cross-sectional view of a retractable needle safety syringe 10 with reduced retraction according to one aspect of the present invention.

  One embodiment of the syringe includes a syringe body 12, a mounting base 14, a plunger assembly 16, a variable vacuum compartment 18, a shaft brake 20, and a ram member 22. Syringe body 12 defines opposing upper and lower syringe body portions 24, 26 and includes a syringe cavity 28. The attachment base 14 defines a shaft hole 30 and is attached to the upper syringe body 24. The mounting base 14 forms a seal with the body 12. The plunger assembly 16 includes a plunger shaft 32 and a piston 34. The plunger shaft 32 defines opposing upper and lower shaft portions 36,38. The plunger shaft 32 is placed through the shaft hole 30 of the syringe cavity 28. The piston 34 is provided on the lower shaft portion 38. The plunger is slidably engaged with the syringe body 12 within the syringe cavity 28. The variable vacuum compartment 18 is provided in the syringe gap 28 between the piston 34 and the mounting base 14. The variable vacuum compartment 18 increases the pulling force when moving toward the lower syringe body 26 of the piston 34 from the lower syringe body 26 to the plunger shaft directed toward the upper syringe body 24. Acts to bring in the state. The shaft brake 20 is attached to the upper syringe body 24 and acts to frictionally engage the plunger shaft 32 to provide first and second frictional forces that oppose the retraction force. The first frictional force is applied to the plunger shaft 32 before the piston 34 reaches the lower syringe body 26. The ram member 22 is attached to the upper shaft portion 36 and is formed to engage with the shaft brake 20 when the piston 34 reaches the lower syringe body portion 26. The shaft brake 20 causes the second frictional force to act on the plunger shaft 32 in accordance with the engagement of the ram member 22 with the shaft brake 20. The second friction force is smaller than the first friction force.

  As shown in FIG. 1, the syringe further includes a needle 46 that is removably mounted to the lower syringe body 26 and extends therefrom opposite to the upper syringe body 24. The piston 34 includes a push 48 that is engageable with the needle holder 50 when the piston 34 reaches the lower syringe body 26. The piston 34 acts to move the needle 46 into the syringe cavity 28 when applying a retracting force to the plunger shaft 32. The needle 46 is attached to the lower syringe body 26 via the needle holder 50. The push-in 48 engages with the needle holder 50 of the needle 46 when the piston 34 reaches the lower syringe body 26.

  Those skilled in the art will understand that in order to perform the suction of fluid into the variable fluid chamber 51 of the syringe 51, first the thumb base 52 of the plunger In order to remove most of the air present between the syringe body 26 and the piston 34, the thumb platform 52 is pushed down toward the syringe body 12 to be depressed. During this depression, the piston 34 of the plunger assembly 16 is forced to slide within the syringe cavity 28 toward the lower syringe body 26. The mounting base 14 and the piston 34 are substantially airtight and liquid tight. Accordingly, reflux of corresponding air and fluid molecules into the variable vacuum compartment 18 of the syringe body 12 is prevented. As a result, the volume in the variable vacuum compartment 18 is increased without the corresponding air molecules and liquid molecules being refluxed, and a vacuum state is formed in the variable vacuum compartment 18. To complete the suction into the variable fluid chamber 51, the thumb platform 52 remains forced down while the piercing tip 54 of the needle 46 is submerged in the fluid contained within the fluid container. When the piercing tip 54 is submerged in the fluid, the thumb base 52 is allowed to move. Due to the vacuum created in the variable vacuum compartment 18 and the reduction in forced depression, the piston 34 is retracted toward the upper portion 24 of the syringe body 12 to move the variable fluid chamber from the fluid container of the desired amount of fluid. Extraction to 51 is executed.

  To inject fluid and retract the needle 46 to the syringe body 12, the operation of the syringe is as follows. The piercing tip of the needle 46 is inserted into a patient or other instrument and in that state fluid is injected. When the thumb base 52 is pushed down, the fluid is extracted from the variable fluid chamber 51 and injected. During this injection stroke, as described above, the mounting base 14 and the piston 34 form an airtight and liquid tight seal, so there is no corresponding air molecule reflux and the volume in the variable vacuum compartment 18. As a result of the increase, a vacuum state is formed in the variable vacuum compartment 18. When the piston 34 reaches the lower syringe body 26 at the end of the injection stroke, the pusher 48 frictionally engages the needle holder 50. Due to the retracting force, the needle 46 is immediately and automatically retracted into the syringe cavity 28 so that the entire needle 46 remains permanently confined within the body 12 and is protectively pressed against the body 12. Be made. This reduces the reuse of the needle 46 and accidental needle sticks, thus preventing the transmission of blood-borne pathogens and other diseases by the contaminated syringe needle 46.

  As described above, when the variable vacuum chamber 18 is expanded during the movement toward the lower syringe body 26 of the piston 34, the vacuum state formed in the variable vacuum chamber 18 is drawn into the plunger shaft 32. Apply force. As can be understood by those skilled in the art, the pulling force is applied to the plunger shaft 32 indirectly via the action on the piston 34. The pulling force changes as the piston 34 moves toward the lower syringe body 26 or toward the upper syringe body 24. In this way, the pulling force increases or decreases. The pulling force is applied to the plunger shaft 32 directed from the lower syringe body 26 to the upper syringe body 24. The pulling force is generated by the vacuum pressure in the variable vacuum compartment 18 as disclosed in one embodiment of the present invention. However, according to another aspect of the present invention, the retracting force is also created by a spring mechanism housed in the variable vacuum compartment 18. Thus, the pulling force need not be generated only by the vacuum conditions in the variable vacuum compartment 18. In this regard, it is contemplated as well, but the variable vacuum compartment 18 need not be airtight to create a retraction force when such a spring mechanism is used internally.

  According to one aspect of the present invention, the shaft brake 20 is attached to the upper syringe body 24 and acts to frictionally engage the plunger shaft 32 to provide a first frictional force against the pulling force. The first frictional force is applied to the plunger shaft 32 before the piston 34 reaches the lower syringe body 26. Nevertheless, according to one aspect of the present invention, the first frictional force may be applied to the plunger shaft 32 even after the piston 34 has reached the lower syringe body 26. For example, as described above, the first frictional force is continuously applied to the piston shaft 34 as the piston 34 moves toward and away from the lower syringe body 26 to draw fluid in preparation for injection. It is made to act. In this regard, the first frictional force applied to the plunger shaft 32 is equal to or greater than the retracting force. According to this advantageous embodiment of the invention, the user does not need to maintain a continuous forced depression of the thumb platform 52 after aspirating the fluid in preparation for infusion. Otherwise, the pulling force applied to the plunger shaft 32 requires the user to keep the thumb base 52 depressed or to suck air into the variable fluid chamber 51. A more troublesome situation is solved by an embodiment of the present invention. If the user does not maintain the forced depressing of the thumb platform 52 after injection and prior to the retraction of the piercing tip 54 from the patient or instrument, the retraction force causes aspiration of fluid from the patient or instrument. The risks associated with this type of accident are mitigated by implementing aspects of the present invention. As described above, the continuous action of the first frictional force of the shaft brake 20 on the plunger shaft 32 counteracts the retracting force and helps avoid such syringe use problems. Overall, the equalization of the retraction force due to the first frictional force provides the user with more control over the aspiration and infusion using the syringe.

  According to one aspect of the present invention, the ram member 22 is attached to the upper shaft portion 36 and is formed to engage the shaft brake 20 when the piston 34 reaches the lower syringe body portion 26. As shown in FIGS. 1 and 2, the ram member 22 is formed integrally with the thumb base 52. Nevertheless, the ram member 22 may be mounted and configured as needed to provide optimal mechanical engagement with the shaft brake 20. Accordingly, engagement of the ram member 22 with the shaft brake 20 is intended to be primarily mechanical engagement, as shown in FIG. As such, the mechanical engagement contemplated herein provides a cost effective, effective and safe means for releasing the shaft brake 20. Nevertheless, engagement of the ram member 22 with the shaft brake 20 is contemplated indirectly through other elements, or engagement may be other than mechanical, such as electrical or chemical. Further, although one embodiment of the ram member 22 is illustrated here, the shaft brake 20 may be variously modified.

  When the ram member 22 is engaged with the shaft brake 20, the shaft brake 20 causes the second frictional force to act on the plunger shaft 32. As described above, the first frictional force is intended to be exerted on the plunger shaft 32 by the shaft brake 20 as the piston 34 approaches and separates from the lower syringe body 26. Therefore, the piston 34 approaches the lower syringe body 26 but does not engage. For example, in one embodiment, the ram member 22 is configured to engage the shaft brake 20 only when the piston 34 is pressed against the lower syringe body 26. In this regard, the ram member 22 and the shaft brake 20 are intended to contact each other prior to engagement of the piston 34 with the shaft brake 20. The engagement process is illustrated in FIG. 2 as contemplated by one embodiment of the present invention. As shown therein, the continuous movement of the plunger assembly 16 toward the lower syringe body 26 acts to cause full engagement of the ram member 22 with the shaft brake 20. Other advantageous features, such as preventive measures, may also be incorporated into embodiments of the present invention to prevent premature engagement. For example, after initial contact, the user notices that further movement toward the lower syringe body 26 of the piston 34 results in engagement of the ram member 22 with the shaft brake 20, which is a sound, Achieved by feel, or other possible indication from the syringe. Such precautionary measures allow the user to control the engagement of the ram member 22 with the shaft brake 20, which further includes the engagement of the piston 34 with the needle 46 and the syringe of the needle 46. This occurs simultaneously with the drawing into the gap 28. Accordingly, various concepts may be incorporated into aspects of the present invention to ensure careful engagement and retraction.

  When the ram member 22 is engaged with the shaft brake 20, the shaft brake 20 causes the second frictional force to act on the plunger shaft 32. According to one aspect of the present invention, the second friction force is smaller than the first friction force. As described above, it is contemplated that the first friction force is equal to or greater than the retraction force, but the second friction force is less than the retraction force. Thus, in the post-injection operation, the ram member 22 engages the shaft brake 20 and at the same time the syringe is configured to engage the piston 34 with the needle 46. Next, due to the engagement of the ram member 22 with the shaft brake 20, the first friction force is replaced by the second friction force, and this second friction force is smaller than the retracting force, so that the needle 46 is inserted into the syringe cavity 28. The result is a nearly unrestricted retraction.

The first frictional force has an associated first normal force 56. Accordingly, the first normal force 56 is directly related to the configuration of the shaft brake 20 and the mounting around the plunger shaft 32, and the pressure applied is the first normal force 56. The first normal force 56 may be increased and decreased depending on concept requirements. As understood by those skilled in the art, the shaft brake 20 and the first normal force 56 applied to the plunger shaft 32 by the shaft brake 20 are configured according to the requirements of the user. As is well known in the art, the first friction force (Ffirst) is expressed mathematically as Ffirst = μk / sNfirst, μk / s represents the motility / sliding friction coefficient, and Nfirst is the first normal force 56. Represents. The first normal force 56 is applied in a specific embodiment with the shaft brake 20 surrounding and contacting the entire circumference of the plunger shaft 32. However, in an alternative embodiment, the first normal force 56 is intended to be exerted by the shaft brake 20 by contacting only a portion of the circumference of the plunger shaft 32.

  The second frictional force has an associated second normal force 58. Similar to that shown above, the second frictional force is calculated using the equation Fsecond = μk / sNsecond. The shaft brake 20 is at least partially released from the plunger shaft 32 upon engagement of the ram member 22 with the shaft brake 20 and thus exerts a second frictional force that is greater than zero, or Equal to zero. In situations where the shaft brake 20 is not fully released from the plunger shaft 32, the second normal force 58 is greater than zero, but the second normal force 58 is most often less than the first normal force 56. Is done. For example, when the shaft brake 20 is substantially released from the plunger shaft 32, the second normal force 58 is less than the first normal force 56, or slightly less than the first normal force 56, but zero Bigger than.

  According to one aspect of the invention, the shaft brake 20 and plunger shaft 32 are contemplated to be made from a variety of materials. In this regard, the static and dynamic friction coefficients vary depending on the material from which the shaft brake 20 and plunger shaft 32 are made. As described above, the first frictional force is contemplated to be equal to or greater than the retraction force during inhalation of fluid into the syringe. As will be appreciated by those skilled in the art, in order to facilitate the use of the syringe, such as that the user is not required to maintain the thumb table 52 depressed during the inhalation action, the coefficient of static friction and An appropriate material is selected based on the coefficient of dynamic friction. As is well known in the art, other considerations and requirements are also addressed by manipulating various material features and their frictional properties.

  Referring now to FIG. 3, the axle brake 20 defines a body outer periphery 60 and includes a hole 62 and a bridge 4. The body periphery 60 is generally defined as the outermost part of the shaft brake 20. The hole 62 is provided in the shaft brake 20 and frictionally engages with the plunger shaft 32. The bridge 64 defines a bridge width 66 and extends radially from the hole 62 toward the outer periphery 60 of the body. The shaft brake 20 causes the second frictional force to act on the plunger shaft 32 as the bridge width 66 increases, and the bridge width 66 increases according to the engagement of the ram member 22 with the shaft brake 20. Prior to the increase in the bridge width 66, the shaft brake 20 applies the first friction force to the plunger shaft 32 as described above.

  In one embodiment of the present invention, increasing the bridge width 66 directly or indirectly increases the size of the bore 62 of the shaft brake 20 correspondingly. Accordingly, as the size of the hole 62 increases, the plunger shaft 32 is released from the hole 62 and correspondingly from the shaft brake 20 as described above. As described above, in a situation where the size of the hole 62 increases rapidly, the second frictional force is very little or substantially zero. However, if the increase in bridge width 66 is a minimum decrease and, consequently, the hole 62 size is correspondingly increased with a minimum decrease, the second friction force is at most less than the first friction force or the retraction force. Bridge width 66 is intended to increase due to deformation of bridge 64 of axle brake 20. Thus, this deformation allows the shaft brake 20 to move away from the plunger shaft 32 and cause a second friction force to act on the plunger shaft 32. The deformation of the bridge 64 is permanent or elastic. In use, it is contemplated that the deformation need only persist until the needle 46 is fully retracted into the syringe cavity 28. Therefore, the shaft brake 20 is made from a material that experiences sustained plastic deformation. The ram member 22 also at least partially separates the bridge 64 to increase the bridge width 66. Thus, the bridge 64 experiences a permanent or temporary physical structural change to increase the bridge width 66 in response to the engagement of the ram member 22 with the axle brake 20.

As shown in FIGS. 1 and 2, the shaft brake 20 further includes a release member 68 provided on the shaft brake 20. The bridge width 66 increases in response to the engagement of the ram member 22 with the release member 68.
Illustratively shown in FIGS. 1 and 2, release member 68 may be configured in a variety of ways, as inevitably determined by concept requirements. For example, as described above, the ram member 22 acts to deform or separate the bridge 64 of the axle brake 20, which can be done directly or indirectly. Thus, depending on the concept, the ram member 22 engages the release member 68 and performs an increase in the bridge width 66. As shown illustratively in FIGS. 1 and 2, the release member 68 may be a shoulder 70 that projects upwardly from the opposite side of the syringe body 12 of the axle brake 20, and the ram member 22 has a piston 34 below it. A shoulder press 72 is sized and configured to engage the shoulder 70 when approaching the side syringe body 26, and the bridge width 66 is responsive to engagement of the shoulder press 72 with the shoulder 70. Increase. The shoulder press 72 is engaged with the shoulder 70 as shown in FIG. 2, the shoulder press 72 is oriented at an angle relative to the thumb base 52, and the shoulder 70 is substantially in contact with the shoulder press 72. Configured to fit. Various other concepts and configurations may also be implemented.

  When the bridge 64 is deformed, the bridge width 66 increases in accordance with the engagement of the shoulder press 72 with the shoulder 70 and the continuous movement of the piston 34 toward the lower syringe body 26. Thus, as described above, the syringe includes a contact position where the user may further displace the piston 34 toward the lower syringe body 26 resulting in a shaft brake 20 or ram member 22 or shoulder press 72. Know that the shoulder 70 is engaged. The shoulder brake 20 then applies a second friction force to the plunger shaft 32 during further displacement. This is achieved by increasing the bridge width 66.

  The axle brake 20 may be configured in various embodiments to increase the bridge width 66 in response to engagement of the ram member 22 with the axle brake 20. For example, as shown in FIG. 4, the brake body defines a body thickness 74 and the bridge 64 defines a bridge thickness 76. The bridge thickness 76 is smaller than the body thickness 74, and the bridge 64 acts to deform in response to the engagement of the shoulder press 72 with the shoulder 70. Therefore, the ram member 22 is configured to cause deformation in the shaft brake 20 when the ram member 22 is engaged with the shaft brake 20. Therefore, if the ram member 22 produces a tensile force via the axle brake 20, having a bridge thickness 76 that is smaller than the body thickness 74 will cause deformation along the bridge 64 and subsequent increase in the bridge width 66. Then, an action of the second frictional force on the plunger shaft 32 is caused. In other embodiments, the bridge thickness 76 is less than the body thickness 74 because the bridge 64 includes a slot and a laminate material extending across the slot. The laminated material has a lower tensile strength than the shaft brake 20, and thus deforms when a tensile force is applied to the shaft brake 20 by the ram member 2 as described above. This deformation also results in an increase in bridge width 66 and subsequent action of the second friction force on the plunger shaft 32. Other embodiments and concepts may be employed to produce the desired result.

  As shown in the illustrative embodiment illustrated in FIG. 5, in another implementation of the present invention, the bridge 64 includes a non-continuous slit 78 that includes a hinge element 80, and the bridge width 66 extends from the shoulder 70 of the shoulder press 72. Increase in the deformation of the hinge element 80 in response to the engagement and the continuous movement of the piston 34 toward the lower syringe body 26. Therefore, instead of the bridge thickness 76 changing relative to the body thickness 74, the bridge width 66 only changes relative to the brake body. In this embodiment, such deformation results in an increase in the bridge width 66 upon engagement of the ram member 22 and the action of a tensile force on the entire shaft brake 20.

  As shown in FIGS. 1, 2, and 4, the shaft brake 20 may be formed to include a fixing member provided on the shaft brake 20. As shown in FIGS. 1 and 2, the fixing member acts to mechanically couple the shaft brake 20 to the mounting base 14. However, it is contemplated that the securing member provides various other effects on the axle brake 20 other than a simple mechanical connection to the mounting base 14. For example, the securing member is contemplated to act to provide at least a portion of the first and second frictional forces to the plunger shaft 32. In this embodiment, the fixing member may be configured as shown in FIGS. Nevertheless, the securing member may be otherwise configured to simply provide a mechanical connection to the mounting base 14.

  In the retracting method of retractable needle safety syringe 10, the syringe includes a syringe body 12, a mounting base 14, a plunger assembly 16, a variable vacuum compartment 18, a shaft brake 20, and a ram member 22. Syringe body 12 defines opposing upper and lower syringe body portions 26 and includes a syringe cavity 28. The attachment base 14 defines a shaft hole 30 and is attached to the upper syringe body 24. The plunger assembly 16 includes a plunger shaft 32 and a piston 34. The plunger shaft 32 defines opposing upper and lower shaft portions 38. The plunger shaft 32 is provided through the shaft hole 30 of the syringe cavity 28. The piston 34 is provided on the lower shaft portion 38. The plunger is slidably engaged with the syringe body 12 within the syringe cavity 28. The variable vacuum compartment 18 is provided in the syringe gap 28 between the piston 34 and the mounting base 14. The variable vacuum compartment 18 is such that the pulling force increases as it moves from the lower syringe body 26 to the plunger shaft 32 directed to the upper syringe body 24 toward the lower syringe body 26 of the piston 34. Act to bring in. The shaft brake 20 is attached to the upper syringe body 24 and acts to frictionally engage the plunger shaft 32 so as to provide first and second frictional forces that oppose the retraction force. The first frictional force is applied to the plunger shaft 32 before the piston 34 reaches the lower syringe body 26. The ram member 22 is attached to the upper shaft portion 36 and is formed to engage with the shaft brake 20 when the piston 34 reaches the lower syringe body portion 26. The shaft brake 20 causes the second frictional force to act on the plunger shaft 32 in accordance with the engagement of the ram member 22 with the shaft brake 20. The second friction force is smaller than the first friction force. The method includes (a) applying a first frictional force against the pulling force to the plunger shaft 32 before the piston 34 reaches the lower syringe body 26, and (b) applying the ram member to the shaft brake 20. And (c) applying a second frictional force against the pulling force to the plunger shaft 32 in accordance with the engagement of the ram member 22 with the shaft brake 20. In one embodiment, for a syringe that includes a needle 46, a further step of the method includes automatically retracting the needle 46 into place within the syringe cavity 28.

  According to another aspect of the present invention, the axle brake 20 defines a body periphery 60 and includes a hole 62 and a bridge 64. The hole 62 is provided in the shaft brake 20 and acts to frictionally engage the plunger shaft 32. The bridge 64 defines a bridge width 66 that extends radially from the hole 62 toward the body periphery 60. The shaft brake 20 causes the second frictional force to act on the plunger shaft 32 as the bridge width 66 increases. The bridge width 66 increases in accordance with the engagement of the ram member 22 with the shaft brake 20. Step (b) of the method further includes the step of increasing the bridge width 66 in response to the engagement of the ram member 22 with the shaft brake 20. Step (b) further includes the step of separating the bridge 64 in response to the engagement of the ram member 22 with the shaft brake 20. The separation step is performed in a state where an acute angle is provided on the ram member 22. Alternatively, the separation process may be performed using a tool provided on or incorporated into the bridge 64 itself, and the ram member 22 may simply activate the bridge 64 separation of the tool. In this regard, the bridge 64 may be variously configured to facilitate its separation. The properties of the material used to make the bridge 64 may also be manipulated as needed. For example, the bridge 64 may be made from a brittle material that separates or breaks upon engagement with the ram member 22.

According to another aspect of the method, the axle brake 20 further includes a shoulder 70 provided on the axle brake 20 and protruding upwardly from the axle brake 20 to the opposite side of the syringe body 12. The ram member 22 includes a shoulder press 72 that is sized and configured to engage the shoulder 70 as the piston 34 approaches the lower syringe body 26. The bridge width 66 increases in response to the engagement of the shoulder press 72 with the shoulder 70. Also, step (b) of the method further includes the step of engaging the shoulder press 72 with the shoulder 70 and deforming the bridge 64 to increase the bridge width 66. The shoulder press 72 is engaged with the shoulder 70 as shown in FIG. 2, and the shoulder press 72 is oriented at an angle relative to the thumb base 52. Shoulder 70 is configured to substantially match shoulder press 72.
Various other concepts and configurations may be contemplated.

  According to another implementation of the method, the syringe further includes a needle 46 that is removably mounted on the lower syringe body 26 and extends therefrom opposite the upper syringe body 24. The piston 34 engages with the needle 46 when the piston 34 reaches the lower syringe body 26. The piston 34 acts to move the needle 46 to the syringe cavity 28 when a pulling force is applied to the plunger shaft 32. The method further includes engaging the needle 46 with the piston 34 and automatically moving the needle 46 into the syringe cavity 28.

  According to another method of implementing the syringe 100, FIGS. 6 to 11 show the syringe 100 (see FIG. 7) with a braking mechanism 112. FIG. As used with reference to the syringe 100 shown in FIGS. 6-14, generally, the retracted position is when the piston 104 is closer to the distal end 114 of the syringe body 110 than to the distal end 116 of the syringe body 110. . However, the retracted position includes a situation where the piston 104 is not in contact with the needle holder 106 and the piston 104 is closer to the distal end portion 116 of the syringe body 110 than the distal end portion of the body 110. The engagement position (see FIG. 13) is when the piston 104 is in contact with the needle holder 106 and is engaged with the needle holder 106. The filling position is when the piston 104 is between the engaged and retracted positions and is adjacent to the needle body 106. By way of example and not limitation, the filling position is such that the piston 104 is closer to or in contact with the needle holder 106 than the distal end 114 of the syringe body 110 but engages with the needle holder 106. It is a time when it is not made (see FIG. 12).

  FIG. 6 is a perspective view of the retractable safety syringe 100. FIG. 7 is a cross-sectional view of the retractable safety syringe 100 shown in FIG. As shown in FIG. 7, the syringe 100 includes a variable vacuum compartment that creates a retraction force to bias the piston 104 and the needle holder 106 and needle 108 to the retracted position when the piston 104 engages the needle holder 106. 102. The retracting force biases the piston 104, the needle holder 106, and the needle 108 to the retracted position so that the needle 108 is placed in the body 110 of the syringe. This configuration prevents accidental needle sticks and needle reuse when the needle 108 is placed in the syringe body 110.

  The syringe 100 further includes a distal end 114 of the body 110 to hold the piston 104 in a predetermined position between the retracted position and the filling position prior to engagement of the piston 104 with the needle holder 106. A braking mechanism 112 is provided (see FIG. 7). The braking mechanism 112 is a conventional non-retractable general purpose, except that the automatic retractable safety syringe 100 causes the syringe 100 to automatically retract the needle into the body immediately after fluid medication is injected into the patient or user. Allowing it to be operated in substantially the same way as a typical syringe. In conventional non-retractable safety syringes, the piston does not move back toward the retracted position when the thumb pressure is released from the thumb platform. The reason is that conventional non-retractable safety syringes do not have a retracting force acting on the piston. This is advantageous during the process of filling the variable fluid chamber with fluid. Similarly, in this embodiment of safety syringe 100, piston 104 does not move toward the retracted position when braking mechanism 112 causes thumb pressure to be released from thumb platform 124. The braking mechanism 112 of the syringe 100 counters the retracting force of the variable vacuum compartment 102 so that the needle 108 does not automatically retract when the thumb pressure is released from the thumb platform 124. Also, after the user or medical professional has injected the fluid medication into the patient, the piston 104 engages the needle 108, and the needle 108 is used to prevent accidental needle sticks and needle reuse. It is automatically retracted into the body 110 of the safety syringe 100. Therefore, the safety syringe 100 also incorporates a safety feature that allows the needle 108 to be retracted into the body 110.

  As shown in FIG. 7, the safety syringe 100 includes a syringe body 110 having a long cylindrical configuration. The body 110 defines a distal end 114 and a distal end 116 and an inner surface 118. Needle holder 106 removably engages tip 116 of syringe body 110, as further described below. Needle 108 is secured to needle holder 106, which provides fluid communication to the variable fluid chamber 120 of the syringe. Plunger 122 includes a thumb platform 124, a shaft 126, and a piston 104. A distal end portion 128 of the shaft 126 is fixed to the piston 104. Further, the piston 104 and the distal end portion 128 of the shaft 126 are placed in the main body 110. The shaft 126 passes through the distal end portion 114 of the main body 110 and extends outside the main body 110 with the distal end portion 130 of the shaft 126 placed outside the main body 110 and fixed to the thumb base 124. . The thumb platform 124 is moved toward the distal end 114 of the body 110 and away from the distal end 114 of the body 110. When the thumb platform 124 is moved toward the distal end 114 of the body 110, the piston 104 is moved toward the filling position and / or the engagement position. When the thumb base 104 is moved away from the end portion 114 of the main body 110, the piston 104 is moved toward the retracted position. The piston 104 is movable within the syringe body 110 between a retracted position and a filling / engaging position.

  The needle holder 106 and the tip 116 of the body 110 form an airtight and liquid tight seal between them. In particular, the distal end 116 of the body 110 has a conical configuration 131 with a cylindrical nub 132. Needle holder 106 contacts base 134. Base 134 has the same configuration as inner surface 136 of cylindrical nub 132. The outer surface 138 of the base 134 and the inner surface 136 of the cylindrical nub 132 are permanently secured to each other and form an air and liquid tight seal. The base part 134 has a through hole, and the needle 108 attached to the needle holder 106 is slid through the hole. The base 134 and the cone also have an interference fit so that the needle holder 106 is not pushed out of the distal end 116 of the body 110 when the wedge element 152 is moved to the release position (described below) (see FIG. 7, see FIGS. 12 and 13).

  7, 12, and 13, the needle holder 106 has a flange 140, a stopper 142, a holding surface 144, and a release surface 146. The holding surface 144 has an outer diameter 148 that is larger than the outer diameter 150 of the release surface 146. Initially, the wedge element 152 rests between the retaining surface 144 and the inner surface 118 of the body 110. The wedge element 152 is in frictional engagement with the holding surface 144 and the inner surface 118 of the body 110 (i.e. takes the holding position; see FIG. 12). In this way, the needle holder 106 can be engaged with the distal end portion 116 of the main body 110. The wedge element 152 is also movable away from the holding surface 144 and around the release surface 146 (ie, assumes a release position; see FIG. 13). Because the release surface 146 has an outer diameter 150 that is smaller than the outer diameter 148 of the retaining surface 144, the wedge element 152 is still engaged with the inner surface 118 of the body 110, but the wedge element 152 is provided around the release surface 146. When released, it is released from the needle holder 106. In this manner, the needle holder 106 can be released from the distal end portion 116 of the main body 110.

  The stopper 142 is formed above the holding surface 144 and protrudes radially outward from the central axis 154 of the needle holder 106. The stopper 142 abuts against the wedge element 152 and prevents the wedge element 152 from being moved to the variable fluid chamber 120.

The flange 140 of the needle holder 106 engages with the piston 104 when the piston 104 is moved to the engagement position. That is, the flange 140 protrudes radially outward from the central axis 154 of the needle holder 106. A longitudinal offset knob 156 formed on the piston 104 engages the flange 140 of the needle holder 106 when the piston 104 is moved to the engaged position. Upon engagement (see FIG. 13), the upper end block knob 158 pushes the flange 140, whereas the lower tip wedge knob 160 tilts when the needle 108 is retracted into the body 110 (see FIG. 14). See) and get caught on the flange 140. To protect against accidental needle sticks and needle reuse when the wedge element 152 rests around the release surface 146 and the longitudinal offset knob 156 engages the flange 140 of the needle holder 106. The lower tip wedge knob 160 acts to pull the flange 140 under retraction force to cause the needle 108 and needle holder 106 to be retracted into the syringe body 110. When the needle holder 106 and the needle 108 are retracted into the main body 110, the lower tip wedge knob 160 pulls the flange 140, and the needle 108 is prevented from being pushed out of the front end portion 116 of the main body 110 after being retracted. Is tilted toward one side of the body 110 (see FIG. 14), the upper end block knob 158 pushes the flange 140.

  The wedge element 152 is provided when the wedge element 152 is provided around the retaining surface (see FIG. 12) so that fluid does not leak out of the variable fluid chamber 120 between the needle holder 106 and the syringe body 110. A watertight and airtight seal is formed between the holder 106 and the syringe body 110. In addition, air is not introduced to the variable fluid chamber 120 between the needle holder 106 and the syringe body 110.

  The piston 104 has an indent 162 that is sized and configured to fit the wedge element 152 when the piston 104 is moved to the engaged position (see FIG. 13). The indent 162 defines a lower surface 164 (see FIG. 12) having a mating configuration with the upper surface 166 of the wedge element 152 (see FIG. 12). When the piston 104 is moved toward the engaged position, the lower surface 164 of the pusher 16 initially contacts the upper surface 166 of the wedge element 152. As the piston 104 is further moved toward the engaged position, the pusher 162 applies a force to the wedge element 152 to slide the wedge element 152 away from the retaining surface 144 and about the release surface. That is, the force applied to the wedge element 152 by the pusher 162 is greater than the frictional force between the wedge element 152, the inner surface 118 of the syringe body 110, and the holding surface 144 of the needle holder 106. When the piston 104 is moved to the engaged position, the pusher 162 moves the wedge element 152 completely away from the retaining surface 144, and the wedge element 152 is now placed around the release surface 146. The In the engaged position (see FIG. 13), a longitudinal offset knob 156 formed on the inner surface of the indent 162 engages the flange 140. In this state, the piston 104 is engaged with the needle holder 106, and the needle holder 106 is released from the distal end portion 116 of the main body 110. Further, the braking mechanism 112 is released. The retraction force created by the variable vacuum compartment 102 biases the piston 104 back toward the retracted position. The engagement between the piston 104 and the needle holder 106 causes the needle holder 106 and the needle 108 to be retracted into the body 110 when the piston 104 is moved toward the retracted position. When retracted, the needle 108 is tilted toward one side of the body 110 to prevent accidental needle sticks and needle reuse, as shown in FIG.

  Referring to FIG. 13, the piston 104 has an undercut groove 168 around the outer edge of the piston 104. A piston seal 170 is placed in the undercut groove 168 and acts to form a water and air tight seal between the piston 104 and the syringe body 110. That is, the piston seal 170 slides on the inner surface 118 of the syringe body 110 when the piston 104 is moved between the retracted position and the engaged position.

Optionally, needle holder 106 has a distally facing conical surface 172. The piston 104 also has a tip-facing conical surface 174 that mates with the distal-facing conical surface 172. When the piston 104 is moved to the engaged position, the conical surfaces 172, 174 are thus adapted to eject the fluid medicament out of the syringe and to be injected into the patient or user.

  The variable vacuum compartment 102 is formed on the opposite side of the variable fluid chamber 120 with respect to the piston 104. Initially, when the safety syringe 100 is supplied to a medical professional, the piston 104 is positioned in the retracted position. In the retracted position, the variable fluid chamber 120 is larger than the variable vacuum compartment 102. As the piston 104 is moved toward the engaged position, the volume of the variable vacuum compartment 102 changes oppositely with respect to the volume of the variable fluid chamber 120. While the volume of the variable vacuum chamber 102 increases, the volume of the variable fluid chamber 120 decreases. Also, as described below, when the piston 104 is moved toward the engaged position, the variable vacuum compartment 102 does not allow air molecules to be introduced into the variable vacuum compartment 102. Since the volume of the variable vacuum compartment 102 increases without additional air molecules being introduced into the variable vacuum compartment 102, a vacuum state is created within the variable vacuum compartment 102. The vacuum condition creates a pulling force that biases the piston 104 back toward the retracted position.

  Referring now to FIGS. 8-11, the attachment base 176 is attached to the distal end 114 of the body 110. The attachment base 176 has an attachment base seal 178 that is placed in the first undercut groove 180. The first undercut groove 180 is formed around the outer edge of the mounting base 176, and the mounting base seal 178 forms an airtight seal between the mounting base 176 and the syringe body 110. The mounting base 176 is secured to the distal end 114 of the body 110 by sonic welding, gluing, or other methods well known in the art. The mounting base 176 has an edge 182 that engages the mating edge 184 of the body 110. When the mounting base 176 is inserted into the distal end 114 of the syringe body 110, the rim 182 is on the mating edge 184 to prevent further insertion of the mounting base 176 into the body 110 of the retractable safety syringe 100. Abut. The mounting base 176 also has an internal undercut groove 186 that is sized and configured to receive a shaft seal 188 that forms a hermetic seal between the shaft 126 of the plunger 122 and the mounting base 176. The hermetic seal is maintained such that the shaft 126 slides through the mounting base 176, i.e., the thumb platform 124 is moved toward and away from the distal end 114 of the body 110. The shaft seal 188 is a wiper type seal.

In use, the safety syringe 100 is supplied to a medical professional or user with the piston 104 in the retracted position. In the retracted position, the variable vacuum compartment 102 does not have a vacuum that creates a retracting force. Further, no fluid is placed in the variable fluid chamber 120. In order to fill the variable fluid chamber 120 with the fluid drug, the user pushes the thumb platform 124 to move the piston 104 from the retracted position toward the filling position. As the piston 104 is moved toward the filling position, its volume increases without introducing additional air molecules into the variable vacuum compartment 102. As a result, the variable vacuum compartment 102 creates a pulling force that biases the piston 104 back toward the retracted position. The braking mechanism 112 counters the pulling force so that even if the medical professional releases the thumb platform 124, the piston 104 is not moved back toward the retracted position. The braking mechanism 112 makes the opposing force equal or substantially equal to the retracting force or creates this opposing force. Even if the medical professional is interrupted while pushing the thumb platform 124 toward the filling position, the medical professional will work immediately and will return later to finish the filling process. When the piston 104 is moved to the filling position, the medical professional releases the thumb platform 124 and grasps the syringe body 110 to guide the needle 108 into the fluid drug container. Even if the thumb base 1244 is released, the piston 104 is not biased by the braking mechanism 112 to return toward the retracted position. With the needle in the fluid drug container, the user holds the container and syringe body 110 with one hand while the other hand overcomes the counteracting force of the braking mechanism 112 and directs the piston 104 to the retracted position. The thumb platform 124 is pulled to move it back. At the same time, fluid from the fluid drug container is transferred from the container to the variable fluid chamber 120. When an appropriate amount of fluid medication is introduced into the variable fluid chamber 120, the medical professional stops moving the piston 104 back toward the retracted position. At this moment, the medical professional releases the thumb platform 124 without the piston 104 being moved further back to the retracted position by the counter force of the braking mechanism 112. For viscous fluid medication, the piston 104 is moved to the filling position to compress the medication container and assist the viscous fluid medication from the needle 108 to the variable fluid chamber 120 when the piston is moved back toward the retracted position. Prior to being moved toward, needle 108 is inserted into the drug container.

  The user or medical professional removes the air trapped in the variable fluid chamber 120 by inverting the syringe 100 with the needle 108 facing upward. The user grasps the finger base 192 (see FIG. 7) of the syringe body 110 with its first and second fingers, taps the body 110 to urge the trapped air toward the needle 108, and In order to remove the trapped air from the variable fluid chamber 120, the thumb platform 124 is pushed down with a finger to move the piston 104 toward the engagement position. After trapped air is removed from the variable fluid chamber 120, the user releases the thumb platform 124 and has a better grip when the user or medical professional inserts the needle 108 into the patient's skin. In this way, the syringe body 110 is gripped. Even if the user or medical professional releases the thumb base 124, the pulling force does not bias the piston 104 back toward the retracted position due to the countering force against the pulling force of the braking mechanism 112.

  After the needle 108 is inserted into the patient's skin, the user depresses the thumb platform 124 to overcome the counterforce of the braking mechanism 112 and move the piston 104 toward the engaged position. As the piston 104 is moved toward the engaged position, fluid from the variable fluid chamber 120 is transferred to the patient. The lower surface 164 of the push-in 162 of the piston 104 initially contacts the upper surface 166 of the wedge element 152. The indent 162 begins to move the wedge element 152 away from the retaining surface 144 and about the release surface 146 as the piston 104 is moved further into the engaged position. In the engaged position (see FIG. 13), the pusher 162 moves the wedge element 152 away from the holding surface 144 and the wedge element 152 rests around the release surface 146. At this point, the needle holder 106 is released from the distal end portion 116 of the main body 110. The longitudinal offset knob 156 is engaged with the flange 140 of the needle holder 106. At substantially the same time, the braking mechanism 112 is released so that there is no resistance against the pulling force created by the variable vacuum compartment 102. When the medical professional releases the thumb platform 124, the retraction force biases the piston 104 back toward the retracted position. The needle holder 106 is moved back toward the retracted position, and the needle holder 106 and the needle 108 are also retracted into the syringe body 110. After the needle 108 is retracted, the needle 108 is tilted to one side of the syringe body 110 so as not to be pushed out from the distal end portion 116 of the body 110 (see FIG. 14).

  The braking mechanism 112 is provided at the distal end portion 114 of the syringe main body 110. That is, the braking mechanism 112 includes a cover 194 (see FIG. 9) and a brake member 196 (see FIG. 9) that are engaged with the mounting base 176. The mounting base 176 defines an internal void. The internal void has a stepped form. The upper stage 198 has a larger inner diameter 200 compared to the inner diameter 202 of the lower stage 204. Upper stage 198 and lower stage 204 are joined together by edge 206. Cover 194 has an outer diameter 208 that is dimensioned to mate with upper 198. Further, the upper surface 210 of the cover 194 is flush with the upper surface 212 of the mounting base 176, as shown in FIG. Cover 194 is secured to mounting base 176 by sonic welding, gluing, or other joining methods well known in the art. The cover 194 has a through hole 214 (see FIG. 9), and the shaft 126 is placed through the hole 214 and is slid. The inner surface 216 of the cover 194 has an inner diameter 218 that is smaller than the inner diameter 202 of the lower stage 204.

As shown in FIG. 8, the brake member 196 is placed on the cover 194 and is frictionally engaged with the cover 194. The brake member 196 is divided into two pieces (see FIG. 10) or more. Preferably, the brake member 196 is divided into two pieces that are mirror images of each other. When the brake member 196 is placed on the cover 194, the outer diameter 220 of the brake member 196 is slightly larger than the inner diameter 218 of the inner surface 216 of the cover 194. In this manner, the brake member 196 frictionally engages the cover 194 and the inner surface 216 of the cover 194 biases the brake member 196 inward toward the shaft 126. The inward biasing amount is set in advance by changing the relative dimensions of the inner diameter 218 and the outer diameter 220.

  When the brake member 196 is placed on the cover 194, the brake member 196 is in the braking position (see FIG. 8). In the braking position, the brake member 196 has a plurality of fingers 224 (see FIG. 10) protruding upward. The inner surface 216 of the cover 194 biases the finger 224 inward, and the finger 224 presses the outer surface of the shaft 126 to induce a frictional force between the finger 224 of the brake member 196 and the outer surface of the shaft 126. Alternatively, it is contemplated that the brake member 196 has a cylindrical inner surface. The entire inner surface of the brake member 196 is in contact with or presses the outer surface of the shaft 126. Accordingly, the friction surface of the brake member 196 that presses the outer surface of the shaft 126 is contemplated to have other configurations to change the amount of inward bias. It is also contemplated that the amount of frictional force between the brake member 196 and the outer shaft 126 may be altered to meet the syringe requirements. For example, the inner diameter 218 of the inner surface 216 of the cover 194 is reduced to further bias the finger 224 against the outer surface of the shaft 126. Further, the tip 226 of the finger 224 (see FIG. 10) is extended inward. The frictional force between the brake member 196 and the shaft 126 has a different finish by changing the material of the brake member 196 and the shaft 126, or on the joint surface of the outer surface 225 of the shaft 126 and the friction surface of the brake member 196. May be changed. During operation, when the brake member 196 is in the braking position (see FIG. 8), the friction force between the finger 224 and the shaft 126 of the brake member 196 is greater than the friction force between the brake member 196 and the cover 194. small. In this manner, when the piston 104 is moved toward the filling position or the engagement position, the brake member 196 is not driven out of the cover 194 and into the second stage (ie, the release position). Since the frictional force of the finger 224 and the shaft 126 of the brake member 196 is smaller than the frictional force of the brake member 196 and the cover 194, the brake member 196 is not driven out of the braking position, and the piston 104 is in the retracted position and the engaged position. When moved between, the shaft 126 slides on the finger 224 of the brake member 196.

  The brake member 196 is movable between a braking position and a release position. When the brake member 196 is moved to the release position (see FIG. 11), the brake member 196 is placed in the lower stage 204 of the internal space of the mounting base 176. The inner surface 216 of the cover 194 no longer presses the finger 224 inward to force the finger 224 of the brake member 196 against the plunger shaft 126 and create a frictional force that opposes the retracting force of the variable vacuum compartment 102. In the release position, the brake member 196 is loose as the lower stage 204 defines a larger volume, and is lowered and separated when the brake member 196 is placed in the lower stage 204. The fingers 224 do not press the outer surface of the shaft 126 and do not create a counter force so that when the user releases the thumb platform 124, the piston 104 is retracted freely toward the retracted position.

In order to move the brake member 196 from the braking position to the release position, the plunger 122 initially contacts the upper surface 230 (see FIG. 9) of the brake member 196 and moves the brake member 196 out of the cover 194 to the lower stage 204 ( Formed with a ram 228 (see FIG. 8) that pushes into it (see FIG. 11). That is, when the piston 104 is moved toward the engagement position, the lower surface 232 (see FIG. 8) of the ram 228 contacts the upper surface 230 (see FIG. 9) of the brake member 196. As the piston 104 is further moved to the engaged position, the ram 228 continuously pushes the brake member 196 downward, causing the brake member 196 to move toward the inner surface 2 of the cover 194.
16 and is biased into the lower stage 204 (see FIG. 11). The outer diameter 234 of the ram 228 (see FIG. 9) is smaller than the inner diameter of the through hole 214 in the cover 194 so that there is no frictional engagement between the ram 228 and the cover 194. As shown in FIG. 8, the ram 228 is formed as part of the thumb platform 124. In particular, the thumb platform 124 has a receiving portion 238 that receives the distal end 130 of the shaft 126. Also, the ram 228 is formed as part of the shaft 126, or the thumb platform 124 and the shaft 126 are contemplated to be integrally formed such that the ram 228 is generally formed as part of the plunger 122.

  In use, the brake mechanism 112 prevents the piston 104 from retracting toward the retracted position as long as the brake member 196 is maintained in the braking position during the operation of the syringe. The user releases the thumb platform 124 regardless of whether the piston 104 is moved back toward the retracted position.

  Along with the fluid medicine filled in the variable fluid chamber 120, the user or medical professional removes the air trapped in the variable fluid chamber 120 by the method described above. The medical professional releases the thumb platform and the piston is not biased back toward the retracted position by the counteracting force of the braking mechanism. The medical professional injects or inserts the needle 108 into the patient's skin and moves the piston 104 toward the engaged position by depressing the thumb platform 124. In the injection process, the medical professional overcomes the pulling force and the counter force of the braking mechanism to move the piston toward the engaged position. When the piston is moved toward the engaged position, the lower surface 164 of the indent 162 contacts the upper surface 166 of the wedge element 152. As the piston 104 is further moved to the engaged position, the pusher 162 pushes the wedge element 152 away from the retaining surface 144 and back around the release surface 146. When the wedge element 152 is pushed away from the retaining surface 144, the longitudinal offset knob 156 engages the flange 140 of the needle holder 106. Around the time when the longitudinal offset knob 156 engages the flange 140 of the needle holder 106, more preferably after engagement of the knob 156 and the flange 140, the ram 228 contacts the brake member 196 and causes the brake member 196 to Move from the braking position to the release position. At this point, the braking mechanism 112 is released. The piston 104 is held at the tip of the syringe only by thumb pressure applied to the thumb base 14 by a medical professional. The medical professional removes the needle 108 from the patient and releases the thumb platform 124. When the thumb platform 124 is released, the retracting force of the variable vacuum compartment 102 biases the piston 104 back toward the retracted position. Engagement of the piston with the needle holder 106 causes the needle holder 106 to be retracted into the syringe body 110 to prevent accidental needle sticks and needle reuse.

In the syringe embodiment described above, the brake members 250, 252 and 254 have various other configurations as shown in FIGS. By way of example and not limitation, the brake member 250 may be an integral split member with an integral hinge 256, as shown in FIG. The brake member 250 shown in FIG. 15 functions in the same manner as the brake member 196 described above, except that the brake member 250 shown in FIG. 15 does not drop away when the brake member 250 is moved to the release position. . Rather, the brake member 250 expands by pivoting about the integral hinge 256 when the brake member 250 is moved to the release position. As shown by the broken line in FIG. 15, the brake member 250 is axially rotated inward when in the braking position. The solid line shown in FIG. 15 shows the brake member 250 when it is moved to the release position. When the brake member 250 is in the braking position, the brake member 250 pivots inwardly around the integral hinge 256 and the finger 258 frictionally engages the outer surface 260 of the shaft 126. Also, when the brake member 250 is moved to the release position, the brake member 250 pivots about the integral hinge so that the finger 258 releases the outer surface 260 of the shaft 126, as shown by the solid line in FIG. To open or spread. Alternatively, as shown in FIG. 16, the brake member 252 is intended to be a split integral member 252 without having an integral hinge. As shown in FIG. 16, when the brake member 252 is moved from the braking position (that is, indicated by the broken line) to the release position (that is, indicated by the solid line), the brake member 252 expands or opens.

  In use, the brake members 250 and 252 are placed on the cover 194 (see FIG. 9, ie, braking position). In the braking position, the brake members 250 and 252 cause the frictional force between the fingers 258 of the brake members 250 and 252 and the outer surface 260 of the shaft 126 by the fingers 258 of the brake members 250 and 252 pressing the outer surface 260 of the shaft 126. So that the fingers 258 of the brake members 250, 252 are biased inward. In this way, when the variable fluid chamber 120 is filled with the fluid medicine and the fluid medicine is injected into the patient, the frictional force between the brake members 250 and 252 and the shaft 126 becomes the retraction force of the variable vacuum compartment 102. Since they are approximately equal, the piston 104 is not biased toward the retracted position. Even if the medical professional or user releases the thumb platform 124 during the filling and injection steps, the piston 104 does not move back toward the retracted position. In addition, during the filling process and the injection process, the brake members 250 and 252 are frictional forces generated between the brake members 250 and 252 and the shaft 126 by the frictional force between the brake members 250 and 252 and the cover 194. Therefore, it cannot be pushed away from the cover 194 (see FIG. 9) to the lower stage 204 (see FIG. 9).

  After the medical professional or user fills the variable fluid chamber 120 and injects fluid medication into the patient, the medical professional removes the needle 108 from the patient and releases the thumb platform 124. Thereafter, the needle 108 is automatically moved to the body 110 of the syringe 10 under the retracting force of the variable vacuum compartment, thereby preventing accidental needle sticks and needle reuse. Thus, at the end of the injection process, the piston 104 engages with the needle holder 106 and the needle holder 106 is released from the syringe body 110. The braking mechanism 112 is released so that the pulling force of the variable vacuum compartment 102 is larger than the frictional force between the braking members 250 and 252 and the shaft 126 at present. In order to release the brake mechanism 112, the brake members 250, 252 are moved from the brake position to the release position. In particular, at the end of the injection process, the lower surface (see FIG. 8) of the ram 228 (see FIG. 8) contacts the upper surfaces 262, 264 (see FIGS. 15 and 16) of the brake members 250, 252. As the piston 104 is further moved to the engaged position, the ram 228 (see FIG. 8) continuously pushes the brake members 250, 252 downward, causing the brake members 250, 252 to move on the cover 194 (see FIG. 9). Move away from the inner surface 216 (see FIG. 9) and into the lower stage 204 (see FIG. 9). When the piston 104 is moved to the engaged position, the brake members 250, 252 are also placed in the lower stage 204 (see FIG. 9) (ie, moved to the released position). In the release position, the brake members 250, 252 pivot outward (see FIG. 15) or extend outward (see FIG. 16) so that the fingers 258 release the shaft 126 of the plunger 122. After the piston 104 is engaged with the needle holder 106, the medical professional removes the needle 108 from the patient and releases the thumb platform 124. At this point, the retracting force of the variable vacuum compartment 102 biases the piston 104 toward the retracted position. The engagement of the piston 104 with the needle holder 106 moves the needle 108 to the body 110 when the piston 104 is moved toward the retracted position.

  The brake members 250 and 252 shown in FIGS. 15 and 16 may be contemplated having a cylindrical inner surface such that the entire cylindrical surface contacts the outer surface 260 of the shaft 126. This increases the surface area contact between the shaft 126 and the brake members 250, 252 and also increases the friction force between them.

An alternative brake member 254 is shown in FIGS. The brake member 254 is shown as an integral member that does not have a split piece (see FIG. 18). The brake member 254 has one or more protrusions 266 (see FIG. 18) that engage the outer surface 260 of the shaft 126 when the brake member 254 is in the braking position. Preferably, as shown in FIG. 18, the brake member 254 has three protrusions 266 that are symmetrical to each other. The protrusions 266 each have a V-shape that deforms when the brake member 254 is in the braking position and is biased inwardly toward the outer surface 260 of the shaft 126. The brake member 254 also has a plurality of bases 268. The outer surface 270 of the base 268 is circular and defines the outer diameter 272 of the brake member 254. The relaxed position of the brake member 254 defines an outer diameter 272 of the brake member 254 that is larger than the inner diameter 218 of the inner surface 216 of the cover 194 and smaller than the inner diameter 202 of the lower stage 204. When the brake member 254 is in the braking position, the inner surface 216 (see FIG. 17) of the cover 194 (see FIG. 17) is smaller than or approximately equal to the outer diameter 272 of the brake member 254 (see FIG. 17). ). As such, when the brake member 254 is in the braking position, the base 268 of the brake member 254 attached to the protrusion 266 is biased inward so that the protrusion 266 also frictions with the outer surface 260 of the shaft 126. Deformed to engage. The shaft 126 slides through the brake member 254 when the variable fluid chamber 120 is filled with fluid medication and the fluid medication is later injected into the patient. Since the friction force between the brake member 254 and the cover 194 is larger than the friction force between the brake member 254 and the outer surface 260 of the shaft 126, the brake member 254 is not pushed away from the cover 194. As the piston 104 is moved to the engaged position to move the brake member 254 from the brake position to the release position, the ram 228 (see FIG. 17) contacts the upper surface 274 of the brake member 254 and the brake member 254. Is pushed out of the cover 194. When the piston 104 is engaged with the needle holder 106, the ram 228 (see FIG. 17) displaces the brake member 254 to the lower stage 204 (see FIG. 17). The lower stage 204 has an inner diameter 202 (see FIG. 17) that is larger than the outer diameter 272 of the brake member 254 when the brake member 254 is in the relaxed or open position. As such, when the brake member 254 is placed in the lower stage 204, the brake member 254 expands so that the protrusion 266 no longer contacts or frictionally engages the outer surface 260 of the shaft 126.

  In use, the brake member 254 is initially placed in the cover 194. When the brake member 254 is placed in the cover 194, the inner surface 216 (see FIG. 17) of the cover 194 has an inner diameter 218 that is smaller than or substantially equal to the outer diameter 272 of the brake member 254. The inner surface 216 of the cover 194 biases the base 268 of the brake member 254 inward, causing the protrusion 266 to deform so as to frictionally engage the outer surface 260 of the shaft 126. The medical professional pushes and pulls the thumb base 120 to fill the variable fluid chamber 120 and inject the fluid drug into the patient. During the filling and injection process, the shaft 126 slides through the brake member 254 and is held in a position between the piston retracted position and the filled position by frictional engagement between the brake member 254 and the shaft 126. . The protrusion 266 of the brake member 254 frictionally engages the outer surface 260 of the shaft 126, and this frictional engagement is greater than the frictional force between the brake member 254 and the cover 194. As such, the brake member 254 is not pushed away from the cover 194 to the lower stage 204 during the injection and filling process.

After fluid medication is injected into the patient, the needle 108 is retracted into the body 110 of the syringe 100 to prevent accidental needle sticks and needle reuse. For this purpose, the piston 104 is engaged with the needle holder 106, the needle holder 106 is released from the body 110 of the syringe 100, and the braking mechanism 112 is released. As described above, the piston 104 is engaged with the needle holder 106 and the needle holder 106 is released from the main body 110. In order to release the braking mechanism 112, the lower surface 232 (see FIG. 17) of the ram 228 (see FIG. 17) is initially moved into the upper surface 274 of the brake member 254 when the piston 104 is moved toward the engaged position. Contact with. The medical professional pushes the brake member 254 further downward by continuously pushing down the thumb platform 124 until the piston 104 is engaged with the needle holder 106. As the medical professional continuously depresses the thumb platform 124, the brake member 254 is moved to the release position (ie, within the lower tier 204). When the brake member 254 is in the lower stage 204, the braking mechanism 112 is released. Further, when the brake member 254 is placed in the lower stage 204, the brake member 254 is loosened outward so that the protruding portion 266 does not frictionally engage the outer surface 260 of the shaft 126. The protrusion 266 of the brake member 254 is separated from the outer surface 260 of the shaft 126 when placed in the lower stage 204.

  Regarding the brake members 20, 196, 250, 252 and 254 described here, the frictional force created between the brake members 20, 196, 250, 252 and 254 and the shafts 32 and 126 is the brake members 20, 196, 250, By changing the material of the 252 and 254 and the shafts 32 and 126, changing the relative outer dimensions of the inner diameter 218 of the cover 194 and the outer diameter 272 of the brake member 254, and other methods described herein, the safety syringe 10 , 100 may be modified and adjusted to meet the requirements.

  In one aspect of the syringe described herein, the retracting force may be alternatively or additionally created by a spring mechanism housed in the variable vacuum compartment 102. Thus, the pulling force need not be created solely by the vacuum conditions in the variable vacuum compartment 102. In this regard, the variable vacuum compartment 102 need not be airtight when such a spring mechanism is used there to create a retracting force.

  In one aspect of the syringe 100 described above, the various seals may be made from rubber or elastic seal materials. Also, other components of the syringe may be made from plastic or other generally rigid material.

  This description of various embodiments of the invention is presented to illustrate preferred embodiments of the invention, and other inventive concepts may be variously embodied and employed in other ways. The appended claims are intended to cover these modifications except to the extent limited by the prior art.

1 is a cross-sectional view of a retractable needle safety syringe with reduced retraction according to one aspect of the present invention. FIG. 3 is a cross-sectional view of a syringe showing the interaction between the ram member and the shaft brake. The top view which shows the axial brake which concerns on another embodiment of this invention. The side view which shows the axial brake which concerns on another embodiment of this invention. The top view which shows the axial brake which concerns on another embodiment of this invention. The perspective view which shows another embodiment of the retractable safety syringe provided with the braking mechanism. FIG. 7 is a cross-sectional perspective view of the safety syringe shown in FIG. 6. FIG. 8 is an enlarged view of the distal end of the safety syringe shown in FIG. 7 with the brake member engaged with the plunger shaft. FIG. 9 is a partially exploded view of the safety syringe shown in FIG. 8. FIG. 9 is a cross-sectional top view of the braking mechanism shown in FIG. 8. FIG. 3 is a cross-sectional perspective view showing a braking mechanism in which a brake member is released from a plunger shaft. FIG. 7 is a front cross-sectional view showing the tip of the safety syringe of FIG. FIG. 7 is a front cross-sectional view showing the tip of the safety syringe of FIG. 6 with a piston engaged with a needle holder. FIG. 7 is a front cross-sectional view of the safety syringe shown in FIG. 6 with the needle retracted into the body of the safety syringe to prevent accidental needle sticks and needle reuse. The top view which shows another embodiment of the brake member by which a brake member is divided | segmented on one side, and an integral hinge is on the other side. The figure which shows another embodiment of the brake member by which the brake member is divided | segmented on one side, and an integral hinge is not on the other side. The perspective view which shows the retractable safety syringe provided with another embodiment of the brake member whose brake member is an integral member. FIG. 18 is a top view of the brake member shown in FIG. 17.

Claims (20)

A retractable safety syringe that prevents accidental needle sticks and needle reuse,
A syringe body defining a distal end and a distal end;
A needle removably engaged with the body tip;
A piston that is placed in the main body and biased toward the main body end by a biasing force when moved toward the front end of the main body, and the piston is between an engagement position and a retracted position. Is movable,
A shaft mounted within the body and extending through the body distal end and movement of the shaft through the body acts to move the piston between the engaged and retracted positions. ,
A brake mechanism movable between a brake position and a release position; and the brake mechanism is attached to the body and provides a force substantially equal to the biasing force when the brake mechanism is in the brake position. A syringe, frictionally engaged with the shaft, wherein the brake mechanism is released from the shaft when the brake mechanism is in the release position. The braking mechanism is
The syringe according to claim 1, further comprising first and second brake members that collectively circumscribe and frictionally engage the shaft when the braking mechanism is in the braking position. The syringe according to claim 2, wherein the first and second brake members are frictionally released from the shaft when the braking mechanism is in the release position. The brake mechanism further includes a cover circumscribing the first and second brake members for biasing the first and second brake members toward the plunger when the brake mechanism is in the brake position. 3. A syringe according to claim 2 characterized in that The syringe according to claim 4, wherein an inner diameter of the cover is equal to or smaller than an outer diameter of the first and second brake members. The syringe of claim 2, wherein the brake member defines a friction surface having a plurality of protrusions. The syringe of claim 6, wherein the protrusion is a finger. A mounting base attached to the distal end of the syringe body, the mounting base having an internal cavity defining an upper surface and a lower surface, the lower surface defining an inner diameter;
A cover that can be placed in the internal space, and an outer surface of the cover is sized and configured to match the upper surface;
The braking mechanism includes first and second brake members, and the first and second brake members can be placed in the cover or the lower surface when moved to the braking position or the release position, respectively. The first and second brake members collectively define an outer diameter, and the outer diameter of the first and second brake members is greater than or equal to the inner diameter of the inner space of the cover and the lower surface of the lower surface. 2. The syringe of claim 1, wherein the syringe is smaller than an inner diameter. A mounting base attached to the distal end of the syringe body, the mounting base having an internal cavity defining an upper surface and a lower surface, the lower surface defining an inner diameter;
A cover that can be placed in the internal space, and an outer surface of the cover is sized and configured to match the upper surface;
The brake mechanism includes a split brake member that can be placed in the cover or the lower surface when the brake mechanism is moved to the brake position or the release position, respectively, and the split brake member defines an outer diameter. 2. The syringe according to claim 1, wherein an outer diameter of the split brake member is larger than or equal to an inner diameter of an inner space of the cover and smaller than an inner diameter of the lower surface. 10. The syringe according to claim 9, wherein the split brake member is divided on one side of the brake member and formed with an integral hinge on the opposite side. A mounting base attached to the distal end of the syringe body, the mounting base having an internal cavity defining an upper surface and a lower surface, the lower surface defining an inner diameter;
A cover that can be placed in the inner space, and the outer diameter of the cover is sized and configured to match the upper surface,
The brake mechanism includes an integral brake member that can be placed in the cover or the lower surface when the brake mechanism is moved to the brake position or the release position, respectively, and the integral brake member defines an outer diameter. 2. The syringe according to claim 1, wherein the outer diameter of the integrated brake member is larger than or equal to the inner diameter of the inner space of the cover and smaller than the inner diameter of the lower surface. The integral brake member is
At least one protrusion having an inner surface in frictional engagement with the shaft to keep the position of the piston between the retracted position and the filling position;
At least one base, the base having an outer surface that is in contact with the inner surface of the cover to bias the base inward, thereby frictionally engaging the protrusion with the shaft The syringe according to claim 11, wherein the syringe is deformed as follows. The integral brake member is
At least one protrusion having an inner surface in frictional engagement with the shaft to keep the position of the piston between the retracted position and the filling position;
At least one base, the base having an outer surface that is in contact with the inner surface of the cover for biasing the base inward, thereby frictionally engaging the protrusion with the shaft The syringe according to claim 12, wherein the syringe is placed as follows. 14. The syringe of claim 13, comprising three protrusions and three bases mounted between the protrusions. 2. The syringe according to claim 1, wherein the braking mechanism is at least two brake members that collectively frictionally engage with an outer surface of the shaft. The syringe according to claim 1, wherein the plunger includes a ram for moving the braking mechanism from the braking position to the release position. The syringe of claim 16, wherein the plunger includes a piston, a shaft, and a thumb platform, and the ram is integrally formed with the thumb platform. A method that acts to automatically retract the syringe,
Providing the syringe with a plunger in the retracted position;
Simultaneously with the pushing step, the thumb is pushed to move the piston toward the tip of the syringe, the biasing force is exerted on the piston of the plunger to urge the piston toward the retracted position, and Frictionally engaging the plunger shaft against the biasing mechanism and the shaft of the plunger to maintain the position of the piston so that thumb pressure is released from the thumb platform;
Engaging the piston with a needle holder;
Releasing the needle holder from the body of the syringe;
Releasing the braking mechanism to move the piston toward the retracted position by the biasing force when the thumb pressure on the thumb platform of the plunger is removed;
Removing the pressure of the thumb on the thumb platform;
Moving the piston to a retracted position under the retracting force. The step of frictionally engaging the plunger shaft comprises:
19. The method of claim 18 including the step of pressing the outer surface of the shaft with a brake member. Releasing the braking mechanism comprises:
The method of claim 18 including moving the brake member from a braking position to a release position.

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