MXPA96003374A - Single-use syringe unit that comprises bag and immobilizable spring clip - Google Patents

Abstract

The present invention relates to a disposable syringe comprising: a hollow barrel having a proximal end and a distal end and having an inner cylindrical side wall extending therebetween, and the means for coupling the needle in the barrel end of the barrel, a substantially cylindrical plunger rod having a longitudinal axis located within the barrel for axial movement of the plunger rod for introducing fluid into the interior and expelling the barrel fluid through the needle coupling means said plunger rod extends beyond the end of the barrel and has a seal and an adjacent piston that expels the fluid at a distance and from said plunger, the rod has a plurality of frustoconical teeth of the ratchet; a immobilizing spring clip, radially resilient, with a circumferential opening mounted on the rod of the piston, the immobilizer spring clip has means of coupling to the rod symbol and at least one lateral wall directed to the outside, an immobilizing tooth having a contact point directed towards said next in contact with the side wall, the coupling means of the rod of the symbol contacting said symbol rod and being mechanically attached to the teeth of the ratchet to move the spring clip together with the plunger rod where the plunger rod is moved towards the far end, and yet the radial locking spring clip expands on the ratchet tooth when the plunger rod is moved towards the proximal end, such As it is held in a relative position with respect to the side wall, as a consequence of the point of contact being coupled to the side wall, the plunger rod is free to move a first time towards the proximal end of the barrel, said clip Immobilizing spring is maintained in a relative position of the side wall by the frictional coupling of the contact point against the side wall as the plunger rod moves towards the proximal end and still, the movement of the plunger rod toward the barrel end causes the plunger coupling means to move the plunger spring clip together with the plunger rod towards the far end, whereby the rod, barrel and spring clip immobilizer allows the barrel of the syringe to be fluid, the volume of the barrel is defined by the determination of the initial location of the spring clip immobilizer on the rod of the piston, by the movement of the plunger rod towards the proximal end, the opening portion of the spring clip which serves to allow flexing and coming from the spring clip on the ratchet tooth in such a way that it facilitates the relative movement of the plunger rod with respect to the spring clip , the movement of the plunger rod towards a distant end expels the liquid through the means that support the tip of the a needle, and a second movement of the plunger rod towards the proximal end is avoided by the frictional engagement between the contact tip and the wall later

Description

UNIQUE USE SYNERGY UNIT THAT COMPRISES I ZAPOR IMMUNE AND CLIP SPRING IMMOBILI RELATED REQUESTS This is a continuation request in part of Application Serial No. 08/195302, filed on February 14, 1994, and entitled Single Use Syringe Unit. The application is incorporated herein by reference as presented in its entirety.

BACKGROUND OF THE INVENTION AND DESCRIPTION OF THE PREVIOUS TECHNIQUE The invention relates generally to syringes and hypodermic needles and, in particular, the invention relates to a spring clip type immobilizer that can be used to convert a hypodermic plastic syringe into a syringe Low cost, difficult to reuse and single use, made of material already medically approved. For the purposes of this invention, the term "single-use" means that the maximum dose placed in the syringe can only be administered once. The syringe can, however, administer the drug several times, however, it can supply only a portion of the entire dose capable of being introduced into the syringe by a single extraction completely next to the plunger rod. To facilitate the appointment of this term and to make it shorter, the term "single-use" is used, which means that it includes one or more possible uses, with each use being the supply of a dose less than the maximum. The cumulative total of the administered doses obtained by all uses can not exceed the minimum dose drawn within the syringe by a single reciprocation distant from the plunger rod. The syringe is truly a single-use syringe when the maximum dose of the syringe (determined by the capacity of the barrel and / or the position of the spring clip of the plunger) is fully administered on its first use. If that happens, the spring clip moves to its fully distal position and all reuse is blocked. When less than maximum amount is administered during the first use, or in subsequent administrations, the subsequent administrations are necessarily less than the maximum amount. There can be only one movement totally 'distal of the plunger rod to administer the medication. In this way, the device is a single-use syringe. The safe and one-time use of hypodermic syringes and needles, and their subsequent disposal, are immediate concerns for health professionals and doctors. Accidentally biting with needles after they have been used means a great risk to patients, doctors and nurses. Risk is a source of great anxiety due to the current concerns of the general public regarding infections with HIV and hepatitis. Therefore, extreme care should be taken in the safe handling and disposal of used needles and syringes. For this purpose, the present invention discloses a single use syringe and needle. Once the syringe and needle have been used (collectively, they will be referred to as a syringe) the mechanism of the present invention avoids their additional or subsequent use. In this way they can be disposed of more adequately than if they could be used again. Thus, they eliminate contamination among patients and among drug users. The device of this invention is compact and, therefore, capable of being implemented in syringes of extremely small barrel capacity, including syringes capable of administering doses as low as 1 cc. On the other hand, the prior art, as will be explained below, can not easily reduce the size in a profitable manner and at the same time maintain the effectiveness of the single-use mechanism, so that they have not been able to be introduced to the market in smaller sizes. to the standard of 3 cc. The axial positioning of the immobilizing mechanism in the syringe barrel of the single use syringes of the prior art is the means that limits a conventional 3 cc syringe to a maximum dose of 1 cc. However, it is definitely desired to have syringes of smaller maximum doses, where the size of the syringe, not only <; The location of the clip determines the maximum dose capacity. It should be appreciated that the present invention can also be adapted for use with 3 cc or with another syringe barrels of maximum dose and, even so, the present invention has particular applicability in syringes of low dose capacity, even up to 0.1 cc. In general, it is recognized that a low-cost syringe is essential to meet the needs of less developed countries and to contribute to the reduction of health costs throughout the world. A low cost would cushion the reuse of syringes that is currently seen in multi-use disposable syringes. Cross-contamination between patients that results from the reuse of the same syringe is avoided with a single-use syringe. It would also reduce the anxiety of patients when faced with the suspicion of a potential infection by the use of a syringe. The present invention provides a simple and inexpensive manufacturing mechanism for limiting the use of a syringe (with or without a needle) to a single use or to a use of a > time. The syringe is intended to be assembled in the manufacturing facility and provided to the physician (or nurse, patient, etc.) for use. The user fills the syringe with the appropriate medicament in the conventional manner, ie moving the plunger away from the cylindrical barrel of the syringe, thus withdrawing the medicament through the tip of the needle and into the chamber of the barrel. Then, also using the conventional technique, the needle is inserted into the patient's skin. The plunger is manually moved relative to the cylindrical barrel thus forcing a piston towards the distal end of the syringe. The force of the piston causes the medication to come out through the tip of the needle. During the dosing administration step of the method, according to the present invention, and as will be explained in more detail below, an immobilizing spring clip travels together with the shaft or arrow of the plunger, and when it reaches the distant position, some points of contact or immobilization are maintained against the inner side wall of the cylindrical barrel with the piston bumping into the base of the clip immobilization spring. A second attempted retraction of the plunger relative to the cylindrical barrel of the syringe is blocked. In this way, no medication can be introduced into the syringe and, therefore, the syringe is unable to be used a second time. A simple, single-use, low-cost syringe is the one provided here. The immobilizer mechanism, avoids the reuse, is automatic, that is, it works to block the reuse without a conscious operation on the part of the user to achieve this operation. The design of a syringe of economic production that has the particularity of a single use and whose safety or one-off operation is difficult to avoid, has been the subject of several patents and studies. This syringe must be easy to manufacture and assembled, its operation must be standard, and it must be able to supply different volumes of fluid, use materials that are universally approved for medical use, preferably requiring standard equipment for manufacturing, such as that used for the preparation of the syringes that are currently used, all important besides the low cost. The present invention achieves the above objects using a novel and singular plunger in association and combination with an immobilizing, novel and singular spring clip. The plunger comprises a plurality of cylindrical ratchet teeth. The spring clip is placed by the manufacturer in a particular location on the plunger in order to limit the maximum dosage of the syringe. In addition, the use of this novel spring clip and plunger blocks the reuse of the syringe. The construction can be incorporated into syringes up to 0.1 cc in size without any loss in efficiency or safety. The operating mechanism of the present invention allows syringes of extremely small volumetric capacity to be manufactured, without loss in his performance. In contrast, the immobilization mechanism of the single-use syringes of the prior art work in very different ways, and therefore syringes of very small volumes can not be manufactured. The present invention is of economic manufacture, has peculiarities to, proof of violation, administers the medicament using conventional techniques, and is made of medically approved materials, besides that it can be elaborated with standard equipment. It is a particular feature of the present invention to provide the thumb contact portion of the syringe plunger as a rupturable disc so that, after use, the user of the syringe can simply bend or twist the disc and remove it. , and subsequently further incapacitate the syringe for subsequent reuse. The ability of the thumb contact portion of the plunger shaft to be disengaged from the syringe also serves as a means of tracking inventory of syringes. In another feature of the present invention, it is required to provide another mechanical immobilizing mechanism. This feature also blocks the second reuse of the syringe. However, it only works when the user deliberately wants to do so, by fully reciprocating the plunger to its maximum remote position. To effect this mechanical immobilization, the plunger and the disc portion in contact with the thumb must be pushed completely towards the distal end of the syringe. When they move in the manner described, the disc portion in contact with the thumb and the plunger are immobilized (unable to withdraw to extract more medication) by the interaction of a male annular dovetail of the plunger that cooperates with a dovetail Annular female of the barrel. Here, a safety mechanism is also provided to prevent reuse of the syringe.

DESCRIPTION OF THE PREVIOUS TECHNIQUE The different approaches described in the patent literature and other publications have generally described various mechanisms for providing disposable syringes, in relation to geometric limitations such as, for example, the minimum total volume that the syringe can contain. . It is clear that there is the limit of the minimum content volume for single-use syringes, which depends not only on the design but also on the limitations in the capacity to produce syringes of small dimensions. Current practice, in which small amounts of medication are going to be injected, prefers the use of syringes of a reduced total volume instead of limiting the movement of a device of greater capacity both for the precision and for the ease of use that are improved with these. The present invention, in contrast to the prior art, uses a totally different mechanism and different operating forces for blocking the reuse of the syringe. The construction of syringes of an extremely small volumetric capacity can be achieved in this way. The safety syringes have been elaborated, in part, providing some degree of protection against accidental damage with the needle. The designs require relatively complex mechanisms or are relatively bulky. They have usually been relatively expensive in their manufacture. Most of the single use limiting mechanisms of the prior art are intended to be used with the typical X-shaped plunger arrows of conventional syringes. The present invention contemplates, on the other hand, the use of a completely novel piston arrow which, in basic form, is a rod comprised of ratchet teeth. In addition, the activation of the security features of the prior art mechanisms can sometimes fail or can be intentionally decoupled. It is believed that the present invention is much more effective in preventing reuse of the syringe. However, as already mentioned, it is of particular importance in the present invention that the device is extremely efficient, inexpensive and capable of being incorporated into syringes of suitable dimensions with a dosage capacity of up to 0.1 cc maximum. In this way, the device can be incorporated into syringes of very small dosages. This is quite desirable. In contrast, the single use or "safety" syringes of the prior art are incapable of being reduced in size or do so in a very difficult manner. They have not been marketed in capacities of maximum 0.1 cc, but manufacturers use standard larger barrel syringes (for example 3 cc) and limit the degree of movement of the plunger shaft to limit the maximum dosage. It is a specific object of this invention to provide a single-use syringe in a maximum capacity as low as 0.1 cc. Previous approaches in the design of disposable disposable plastic syringes can be classified as follows: (a) Immobilization of the plunger after administration; (b) Decoupling of the plunger; (c) Removal of the needle inside the syringe barrel after dose administration, - (d) Physical destruction of some section of the syringe, - (e) Chemical means to disable the syringe after the first use, - and (f) ) The use of additional means such as sleeves to prevent reuse of the syringe while simultaneously offering protection against pitting. A syringe of the present invention utilizes a mechanical method to immobilize the plunger against further use by a novel immobilizer spring clip mechanism, as described below. The immobilizer mechanism of the prior art generally operates in conventional X-shaped pistons, and in some cases in a cylindrical piston. In the use of the X-shaped pistons, the pistons are maintained in axial alignment with the axis of the barrel by the edges of the piston. In the use of the immobilizing device in a cylindrical plunger, the stationary devices were symmetrical, extending completely around the plunger. In this way, these pistons also remained in axial movement with the barrel. The axial alignment between the barrel and the plunger in the immobilizing and X-shaped clip devices of the prior art and in those cylindrical pistons that surround the stationary clips, avoid the reduction in the volumetric capacity of the syringe. The present invention, in contrast, utilizes a novel immobilizing mechanism of a cylindrical plunger. The structure and manner of operation of the spring-type immobilizing clip of the present invention results in a radial displacement of the plunger within the barrel. This non-axial alignment between the plunger and the barrel allows the manufacture of disposable syringes with a volumetric capacity much smaller than previously possible. U.S. Patent No. 4,383,606 uses sharp edges in a plunger, cam or barrel to immobilisably secure the syringe having an X-shaped plunger. U.S. Patent No. 4,367,738 discloses a non-reusable syringe which uses a plurality of flexible and rigid tines. U.S. Patent No. 4,731,068 discloses spider-shaped spikes rigidly secured and mounted on a cylindrical plunger to immobilize the syringe after administration and prevent its reuse.

U.S. Patent No. 4,952,206 uses tines to allow a washer located within a valve to impede fluid flow after administration of the drug. U.S. Patent No. 4,961,728 uses non-parallel tines on an immobilizing member for an X-shaped plunger. U.S. Patent No. 4,979,943 provides a reversible touch member that allows movement of the plunger in only one direction . U.S. Patent No. 5,000,737 uses a spiked, circular or ribbed immobilizer that couples to an X-shaped plunger. U.S. Patent No. 5,021,047 and U.S. Patent No. 5,138,466 uses immobilizing tines that completely surround the plunger. The movement of the immobilizer in relation to the plunger causes it to flex in an axial mode as it is forced onto the ratchet teeth. - U.S. Patent No. 5,205,825 uses an insertable clip to immobilize the X-shaped pistons. WO 89/00432 uses a ratchet plunger and a ratchet wall to prevent reuse.

U.S. Patent No. 5,000,737 relates to a single-use disposable syringe. The figures show a device adapted to be placed on a conventional X-shaped piston. The points directed outward from the claimed groove are intended to be enclosed in the inner cylindrical side wall or surface of the needle barrel in order to prevent disc movement. in relation to the barrel, when the arrow of the plunger moves in the next direction (the direction to extract the medicine inside the barrel). The inwardly directed edges are adapted to engage the adjacent walls of the X-shaped plunger so that the device travels together with the plunger when the plunger moves distally (to deliver the medication). Figures 8 to 16 of the identified patent relate to the claimed invention of the '737 patent. The device is intended to be kept in a quadrant of the syringe barrel defined by the X-shaped plunger member. It is described according to the patent as "stretchable", ie its length is greater than its width dimension. The present invention, on the other hand, as will be explained below, is not elongated. It is manufactured in an easy and compact way for syringes of small size. It is less expensive in its manufacture and is believed to be much simpler to manufacture. It will not fail in case of axial misalignment and in fact, it works by axial non-alignment. When constructed in this way and operating in a matching fashion, the volume of the syringe can be made much smaller than that which can be constructed with prior art syringes. In addition, the present invention contemplates the use in connection with a new plunger. The immobilizing spring that is now presented, is not confined within a quadrant of the barrel, defined by an X-shaped piston, but extends only partially around a new cylindrical piston inside the barrel. This provides a more uniform pressure of the locking mechanism against the inner side wall of the barrel and ensures that the present invention is useful to avoid reuse of a single use syringe. The manner of operation, that is to say, when the plunger is being pushed in an off-center manner or out of axial alignment with respect to the axis of the barrel of the syringe, has a number of advantages over the prior art. The patent • 737 also shows a disc-like member that functions somewhat like the groove claimed in the '737 patent. It is also intended for use with conventional X-shaped pistons. And it also seems difficult to reduce the size to manufacture syringes of 0.1 cc. United States Patent No. 5,151, 088 is also related to a syringe unit and safety needle. The disposable syringe and needle unit is illustrated and described with a small rigid retractable needle guard provided in the syringe. After injection, the needle guard extends into a locked position that covers the needle. The cover only assumes the locked position when the user presses the plunger of the syringe beyond the point of zero volume. In this way, if the user accidentally or consciously does not reach that point zero, the device will not be blocked or prevent its reuse. It is an object of the present invention to automatically avoid the reuse of a syringe in order to avoid contamination between people, which is a consequence of the reuse of the needle. An automatic coupling immobilizer mechanism is not achieved by device '088. The use of the invention of the '088 patent, makes a user who wishes to violate the mechanism and reuse the syringe, can avoid the locking mechanism by deliberately making the needle plunger not be pressed beyond the point of zero volume. U.S. Patent No. 5,205,825 (Allison et al.) Relates to an insertable element - to avoid the reuse of plastic syringes, This device, similar to that shown in Free et al. 737, provides a locking mechanism adapted to fit conventional existing syringes by inserting the same over the standard X-shaped plunger into a plastic barrel cylinder of the syringe. The same comments made previously in relation to the Free et al. Device also apply to the device of the Allison et al. Patent, that is, in relation to its inability to effectively and efficiently have a dose of smaller maximum size , and in addition, the advantages achieved by the present invention as a consequence of the non-alignment of the piston with the axis of the cylinder barrel, are not achieved with these patents. U.S. Patent No. 5,067,942 is related to a single-use hypodermic needle. When the needle unit and the syringe are assembled, two separate tabs maintain within a basket force the liner to retract and expose the port in the needle, whereby a fluid can flow through the needle. When the needle syringe is disassembled, the tabs are separated from the basket and effectively destroyed to prevent their use when retracting the cover or liner. The present invention is believed to be much simpler and less expensive in its manufacture, in addition to - <• - automatic and more easily adaptable for syringes of smaller size, than what is shown in the '942 patent. A number of designs of safety syringes incorporating needle covers have also been proposed. U.S. Patents 4,904,791 and 4,982,842 employ jaw members pivotally mounted on a syringe barrel to cover a needle after use. U.S. Patent No. 4,969,877 discloses a needle unit in which an outer housing is provided around an internal chamber or syringe portion that slides over the outer housing to an operating position and to a retracted position in the front and rear ends of the outer housing, respectively. U.S. Patent No. 4,013,073 discloses a collapsible, single-use syringe wherein the interior of the collapsible wall is constructed so that when the walls are pressed together the medication is discharged, and they lock and therefore make that the device can not be reused. U.S. Patent No. 4,022,206 teaches a method and apparatus for storing and administering a vaccine in a pre-packaged single-dose system. No exposure is made stating that the unit is made mechanically incapable of subsequent use. U.S. Patent No. 4,391,273 teaches a rigid type syringe which includes a pin which is attached to the piston and which penetrates the lower wall of the cylinder after the injection has been completed. This also makes the syringe inoperative after a first use. In an alternative embodiment, the patent shows a knife that allows the movement of the cylinder in a forward direction but the knife cuts the side wall of the cylinder in case there is an attempt to recycle the piston or reuse the syringe. The above techniques for preventing reuse of needle syringes include various arrangements for immobilizing the plunger of the syringe after it has been used a first time and then reciprocating the end of its travel to inject the contents of the syringe. For example, U.S. Patent No. 4,731,068 discloses a two-piece stationary construction having a band or sleeve assembled at the injection end of the syringe and sized to slide frictionally along the internal wall of the syringe. syringe. An element similar to a spider is mounted in a fixed position on the plunger and has a point with spikes coupled with the sleeve. When the plunger retracts first, the spider element and the sleeve travel to the end of the syringe, along with the plunger. When the plunger is pressed towards the injection end, the sleeve is at the distal end (through the frictional engagement with the inner wall) while the spider element travels towards the injection end with the plunger. If a second attempt is made to retract the plunger, the prongs of the spider element, which are now exposed to the inner wall in the absence of the sleeve, will engage the inner wall of the syringe and prevent a second retraction. An alternative embodiment shown in the '068 patent has the sleeve slidably supported on the plunger and coupled with the spider element. This element is provided with teeth similar to curved springs assembled at the distal end of the syringe. In the first retraction, the sleeve is engaged with the spider element, and in the first depression, it moves towards the injection end to expose the teeth of the spider element. An attempt to retract the plunger a second time will prevent the engagement of the teeth with the plunger. Other devices, for example, U.S. Patents 4,781,684; 4,493,703; 4,391,272 and 4,367,738 provide modifications to the wall structure of the plunger or syringe. These allow only movement in one direction of the plunger or immobilize or incapacitate the plunger after a first depression. They also relate to single-use syringes. U.S. Patent No. 5,290,235 relates to a non-reusable syringe. During use, an immobilized member interacts with the guide arrangement of the plunger and the inner surface of the hollow body of the syringe to allow a first extraction stroke and an administration stroke, but to avoid a second stroke of administration of the plunger. The device shown in the '235 patent generally comprises a conventional hollow body syringe, an elongated plunger rod extending out of the body to facilitate movement of the piston, - the plunger rod has a guiding means that carries an immobilizing member, similar to a plate, with at least one obstructing projection facing the inner surface of the barrel, wherein the guide causes the relative pivoting movement of the immobilizing member, from a first position where the plunger moves freely in the remote direction, to a second position where the tines are attached to the lower wall of the barrel. The construction of the device of the '235 patent is much more complicated than that of the present invention. The present invention contemplates the use of a cylindrical plunger arrow of simple molding, but with ratchet teeth, having a spring clip mounted thereon. The original location of the spring clip will determine the maximum volume of the liquid supplied. The device of the '235 patent, in contrast, shows a complicated plunger. It does not seem suitable for mass production. The present invention allows a single plunger rod to be used for a variety of maximum dose syringes. In the '235 patent, each syringe with a different desired maximum capacity requires a different distance of the plunger between the first face 22 and the stop face 26. The present invention is extremely easy in its manufacture, manufacture and assembly. It is also easily capable of being used with standard size syringe barrels and, furthermore, of commercial importance, it is fully capable of being sized in smaller form for use in connection with syringes having a maximum dose capacity as low as 0.1 cc. The present invention is fail-safe, that is, it is self-operating and, in the preferred embodiment, as will be explained more fully, provides several locking mechanisms, thus ensuring that the reuse of a syringe is not present. stable. The present invention also allows the selective axial location of the cylindrical plunger shaft immobilizing spring mechanism, so that maximum doses can be provided by the manufacturer even when the syringe barrel and the plunger can be manufactured in a single size. In this way, the location of the mechanism of the immobilizer spring with respect to the barrel and the plunger, at the time of manufacture, ensures that the doctor, the nurse, the technician or the user doing the administration, can not administer an overdose of the medication in particular. The immobilized spring mechanism can ensure a variety of initial locations at the time of manufacture depending on the placement location on the plunger, so that manufacturing can be saved, since only a single plunger element and a single barrel need to be manufactured. cylindrical. The position of the original location of the immobilizing spring mechanism relative to the plunger determines the maximum amount of dose that a particular syringe is capable of delivering. In this way, the present invention not only provides a mechanism to ensure that syringes can not be reused, but also, the spring-immobilizer mechanism limits the amount of the drug that can be administered for a particular use of the syringe. The present invention, as will be seen in more detail below, also provides a backup security mechanism for additionally incapacitating the syringe after its first use. This particularity, however, is not automatic, but requires the user to physically separate the disc portion in contact with the thumb of the plunger from the plunger's arrow, in order to mechanically disable the syringe so that it is not used a second time. . Removal of the thumb contact portion serves the secondary purpose of facilitating inventory control since the disks, the remaining portion of the syringe after the rest has been discarded, can be used to facilitate control of Inventory. It is a further object of the present invention to provide yet another feature of immobilization that prevents the syringe from being used a second time. In this embodiment, a complete reciprocal reciprocation of the plunger relative to the syringe barrel will cause an annular male dovetail portion of the disc in contact with the thumb to engage and mechanically lock within an arrangement similar to an annular female dovetail. Cylindrical barrel. This immobilizes the disc and the arrow completely inside the barrel and prevents the movement of the arrow outward from the barrel. Blocking this movement prevents more medication from being introduced into the body of the syringe, thus preventing the device from being reused. The geometry of the present invention allows the device to be elaborated in maximum doses as low as 0.1 cc. This is due to the fact that, as will be explained in more detail, the immobilizing device operates radially, ie pushes the plunger rod off the shaft in the barrel. In this form of operation, the immobilizer clip avoids being of a single thickness. It does not need to surround the plunger rod. In the way in which they are constructed and operated, the plunger rod, the barrel and the immobilizing clip can be dimensioned in a small way without loss of function, up to a size in which medication is administered, with a volume as low as 0.1 cc as maximum dose. This type of particularities are not available with the prior art.

SUMMARY OF THE INVENTION The present invention relates to single-use syringes where reuse is mechanically blocked. It is an object of the present invention to provide a single-use syringe that is easy to construct, inexpensive in its manufacture and that automatically avoids reuse. It is another object of the present invention to provide a low cost syringe that is capable of mechanically blocking reuse and that is made with a very small dosing capacity. For example, it is a specific object of the present invention to provide a disposable syringe capable of having a maximum dose as low as 0.1 cc. Another object of the present invention is to provide a spring-like mechanism that is inexpensive, which when placed on a plunger shaft with ratchet teeth, limits the amount of medicament that can be introduced into the barrel of the syringe and then administered . The initial location of the immobilizing spring mechanism, relative to the cylindrical arrow with ratchet teeth, determines the maximum capacity of that particular syringe. Thus, it is a specific object of the invention to provide a disposable syringe capable of having a variety of maximum dose capacities depending on the location of the spring clip with respect to the plunger shaft. The manufacture of a barrel of a single size, therefore provides economy in manufacturing. It is a further object of the present invention to ensure that a disposable syringe is provided which can not be intentionally incapacitated in an easy manner. It is also an object of the invention to secure a single-use syringe that is intended to be operated by the radial displacement between the plunger and the axis of the barrel of the syringe. This is achieved, in part, by the use of a new plunger arrow that is basically a rod and by the use of a clip similar to a spring that flexes radially inward and outward, and that can be placed on the arrow cylindrical The non-axial alignment between the arrow of the cylindrical plunger and the inner wall of the barrel of the syringe allows the single-use immobilization mechanism to be sized smaller for syringes capable of delivering doses as low as 0.1 cc. A specific object of the invention is to provide a single-use immobilizing mechanism for a disposable syringe that is capable of being used in plunger arrows. By eliminating the plunger in the form of X, the easier processing of small dimensions is allowed with the invention. The use of a plunger rod with ratchet teeth and the immobilizing spring clip of the present invention eliminates the need shown in the prior art for immobilizing clips substantially surrounding the cylindrical plunger arrows. In this way, very small capacity syringes can be made. The plunger shaft of the present invention comprises a plurality of cylindrical ratchet teeth. The immobilizing spring, as will be explained, is intended to be initially located on one of the selected teeth of the plunger. In this way, the present invention allows a more precise dosage limit than is available with prior art devices. Mechanical interlocking between the immobilizing spring and the plunger ensures maximum dosage in fixed integral quantities while the prior art controls the maximum doses by infinitely variable sliding locations of a groove along the X-shaped legs of the plunger, which They are not so easy to control. It is a further object of the present invention to provide a portion of the thumb contact disc on the plunger shaft, which can be selectively bent or twisted and removed from the plunger shaft after the syringe has been used. In this way, the disc portion in contact with the thumb can be used to maintain the tracking of syringe use and the inventory of syringes. In addition, the removal of the disc portion in contact with the thumb separating it from the arrow of the plunger, serves to incapacitate the syringe avoiding its possible reuse. It is another object of the present invention to provide another immobilizing mechanism that incapacitates the syringe so that it is not reused after a first intended use. This immobilizing mechanism is achieved by co-operating an annular male dovetail of the disc portion in contact with the thumb having the plunger arrow, with a female-like dovetail-like receptacle at the proximal end of the barrel of the syringe. A complete reciprocating cycle of the plunger shaft relative to the cylindrical barrel of the syringe serves to mechanically lock the plunger shaft in its full distal position, thus preventing a second unauthorized or unintended withdrawal of the plunger rod from the barrel of the barrel. The syringe. Another object of the present invention is to provide a mechanism where syringes of identical dimensions can be restricted to contain and administer different doses, thus reducing the need to have syringes of various sizes. The present invention is directed to a mechanical means using a spring clip and ratchets to achieve the aforementioned features that are desirable. The operation of the syringe unit is based on a loosely coupled spring clip that allows the syringe to be filled when the plunger is withdrawn. The clip is practically semi-cylindrical and has the ability to flex radially, both inwardly and outwardly, and contains barbs directed outwardly so as to allow them to be positioned sufficiently independently to conform to variations in barrel diameter due to the tolerances or imperfections of the manufacture. The present invention also has alignment elements that function as the immobilizing clip advances toward the needle. The alignment mechanism adds stability when the plunger attempts to be reused in a second fill, as described below. The plunger contains a front seal to provide smooth operation by applying a force evenly distributed in the incrusted tines during any second attempt to remove the plunger, after a first administration of medication. As the plunger is withdrawn to fill the syringe, the immobilizing spring clip, while stationary in the syringe barrel, is forced to have a cam movement on one or more of the teeth of the cylindrical plunger with ratchet teeth, as result of a radial flexion movement. The clip can be adjusted to the variable diameter of each tooth of the plunger because "it is radially open, having only an almost semi-cylindrical shape." During the administration of the fluid by the forward movement of the plunger and the piston, the clip flexes radially. It is carried or pushed forward in relation to the barrel by means of the plunger After the injection, with the plunger in its most forward position, the clip prevents a second withdrawal in the backward direction of the plunger, since the tines are embedded inside the plunger. the plastic barrel wall Any attempt to bypass the resulting friction results in the piston rod breaking as its tensile strength, reduced by the reduced cross section of the piston at predetermined indications, is less than the force necessary to overcome the frictional resistance provided by the tines embedded in the inner wall of the barrel. Second sections or more sections of reduced diameter can be provided in the plunger for additional protection against reuse. It is an object of the present invention to provide a design that can be easily fabricated by standard molding and assembly methodology at a cost comparable to that currently experienced in the manufacture of disposable plastic syringes.It is another object of the present invention to achieve the smooth operation of the syringe. It is an object of the invention to provide a single-use syringe that does not clog, particularly for smaller volume syringe sizes. Another object of the invention is to provide a plunger and an immobilizing spring clip in which the mechanism allows the positioning and actuation of the immobilizing function as a result of the radial flexing of the immobilizing member around the plunger and inside the barrel of the syringe. It is still another object of the invention to provide an immobilizer spring clip having flexible locking or contact points capable of interacting independently with the wall of the barrel and allowing variations in the diameter of the barrel. Another object is to provide a syringe wherein an attempt to reuse leads to the syringe being inoperable. Still another object is to provide a secondary fail-safe mechanism, ie a complementary means that provides tamper-proof capabilities. It is another object of the invention to provide a design that offers the above features in syringes capable of accurately administering an amount as low as 0.1 cc of liquid. Yet another object is to provide the above features within a simple syringe having a variable maximum predetermined volume of fluid that can be introduced into the syringe. It is another object of the present invention to achieve the desired prior objects using materials that have already been approved by official and governmental regulations. Still another object of the invention is to allow the syringe to be capable of being modified to minimize accidental needle stings. Still another object of the present invention is to provide a multiple immobilizing mechanism which ensures the disabling of the syringe by different approaches and which prevents access to the operative immobilizing mechanism. It is another object of the present invention to allow different amounts of fluid to be delivered with a given barrel diameter. The objects, features and advantages of the invention will become apparent from the following detailed description of the preferred embodiments thereof, considered in conjunction with the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective side view of the syringe portion of the present invention showing the immobilizer spring in its initial position, in the form in which it is marketed by the manufacturer, in free form on the Plunger arrow with ratchet teeth. This Figure shows the syringe of the present invention in its configuration intended to be distributed to a user for the first filling with the medicament and the subsequent administration thereof. The needle extending from the syringe has a conventional configuration; Figure 2 is a perspective side view of the present invention in its position after medically filling and ready for administration, - Figure 3 is a perspective view of the present invention after administration of the medicament, showing the clip immobilization spring in its most advanced or distant position, in the manner in which it is carried by the ratchet teeth of the plunger; Figure 4 is a perspective view showing the manner in which the plunger is separated, as a consequence of a second attempt at the proximal movement of the plunger, - Figure 5 is a perspective view of the preferred embodiment of the plunger; Figure 5a is a perspective view of the resilient insert or piston of the plunger mechanism, - Figure 6 is a side plan view of a second embodiment of a plunger, this version contains two free spaces of reduced area, - Figure 7 is a side view of a third plunger mode with a single space of reduced area and an enlarged area to avoid violation; Figure 8 is a side view of a fourth plunger embodiment containing three reduced areas, one adjacent to the thumb contact disc; Figure 9 is a top view of the immobilizing spring clip before being conformed to its three-dimensional shape for use in the barrel of the syringe, - Figure 10 is a perspective view of the immobilizing spring clip after conforming to its shape, - Figure 11 is a cross-sectional view taken along lines 11-11 of Figure 3; and Figure 12 is a cross-sectional view of an alternative embodiment of the barrel, the plunger and the thumb-engaging disc portion of the plunger.

DETAILED DESCRIPTION OF THE DRAWINGS AND THE PREFERRED EMBODIMENT As best seen in the drawings, the present invention, a syringe 10 comprises a main cylindrical body 12 and a reciprocating plunger member 14, slidable, received and contained within the cylindrical body 12. Preferred material for the cylindrical body is a medical grade polypropylene, clear, which is insoluble and inert with most drugs and has been approved by the FDA. The preferred plunger material is medical grade propylene modified by the incorporation of a suitable additive in order to provide brittle properties to the resin. A needle 15 is attached to the distal end of the syringe 10 in a conventional manner. Of course, the syringe can be sold separately from the needle. The details of the construction of the needle and its manner of attachment to the syringe do not need to be fully understood or appreciated for the present invention. The needle 15 is secured to the tip 18 of the cylindrical body 12. For the purposes of this description, the end of the cylindrical body 12 towards the tip and the needle will be referred to as the distal or distal end, and the direction or movement towards this end will be it will be called distal or distant. The other end of the syringe, i.e., the end of the plunger member 14 having the thumb contact disc 20 and the finger lugs 26 is termed the proximal end and the direction or movement towards that end is referred to as "next". or proximal. As can be seen in the Figures, the thumb contact disk 20 is secured to the proximal end of the plunger member 14 and facilitates the proximal removal or movement of the plunger member 14 relative to the cylindrical body 12, as well as the administration of the medicament or the distal movement of the plunger member 14 towards the tip 18 of the cylindrical body 12. The proximal movement introduces medication through the needle and into the barrel or chamber of the syringe while the distal movement administers the medicament, contained in the barrel, through the tip 18 and the needle 15. The medicament is administered from the cylindrical body or barrel by the sliding action of the resilient piston 44 against the internal side wall 17 of the barrel. The thumb contact disc 20 is secured to a segment 22 of the plunger member 14. In the embodiment of the invention shown in Figure 8, the segment 22 is partially frustoconical and represents a fracture plane 24 of reduced diameter. As seen in Figure 8, the reduced diameter end of the segment 22 forms the base of the thumb contact disk 20. After using the syringe, the thumb contact disk 20 can be bent with respect to the fracture plane 24 until the disc breaks and separates. Removal of the thumb contact disc 20 facilitates the further disabling of the syringe, after use, ensuring that it can not be used again, since it would be difficult to reciprocate the plunger without the presence of the disc 20. Disc 20 serves not only to incapacitate the syringe from further reuse, but also as a compact and convenient inventory control mechanism. Referring again to Figures 1 to 4, the cylindrical body 12 is provided, at its proximal end, with a finger grip or finger support plane 26. A convenient support surface for the fingers is provided for reciprocation of the plunger member 14 with respect to the cylindrical body 12 and a resting surface for the fingers of the user is provided during use. The plunger member 14 is a rod, in its basic configuration. The ratchet teeth 28 are tapered frusto and extend over a portion of the length of the plunger member 14. As best seen in the Figures, each ratchet tooth 30 comprises an inclined or cam-shaped surface 31 extending toward outside (from the proximal to the distal end) and is inclined, and is molded towards an adjacent ratchet tooth by a common base or plane 32 having an enlarged diameter DI (for the upper relative tooth) and a reduced diameter D2 (for the tooth relative lower). In the embodiment shown in Figure 7, a piston seal 34 surrounds the plunger member 14 directly above the closest ratchet teeth. The plunger seal 34 can be integrally molded or formed with the plunger, or alternatively, it can be a separate resilient component. A tight fit of the plunger seal 34 (or segment 22 of the plunger shown in Figure 1) to the barrel limits access to the immobilizer spring clip and makes the device tamperproof. The narrowness of the parts between the seal 34 (and / or the segment 22) and the internal side wall 17 of the barrel is represented by the small clearance 41. The piston seal 34 or the segment 22 has an outer diameter greater than the diameter DI of the ratchet teeth and, in the embodiment of Figure 7, the piston seal 34 has a diameter approximately equal to that of the inner side wall 17 of the barrel. The plunger seal provides a barrier between the outside of the syringe and the ratchet teeth, so that foreign objects can not enter between the plunger member 14 and the inner side wall 17 of the cylindrical body 12. In this form, the seal of plunger 34 or segment 22 serves as a seal device to prevent unauthorized access to the immobilizer spring 40 so that it can not be incapacitated for its intended use. In an alternative embodiment, the plunger seal 34 is rubber and is in physical contact with the inner side wall 17 and, at least in part, is partially compressed by the relative diameter of said side wall. The distal end of the plunger member 14 comprises a piston-type or fluid-pushing seal member 44. Preferably it is made of a rubber-like substance, which is a partially compressible material. Preferably, the piston is of a medically approved synthetic rubber. Again, the piston 44 can here be integrally molded or formed with the plunger or with a separate rubber component. As seen in Figures 5, 5a and 6 to 8, the piston can be attached to the distal end of the plunger by a blind hole that is forcibly mounted on a frustroconical cone, see Figure 7. This secures the rubber piston with the plunger . The piston 44 has a diameter, when radially compressed by the side wall 17 of the barrel, practically equal to the diameter of the internal side wall 17 and provides a sliding contact, although sealing, between them. When the plunger member 14 is reciprocatingly moved within the cylindrical body 12, all the fluid (distal to the piston 44) will be pushed through the tip 18 and, therefore, through the needle 15. The sealing member 44 also prevents any medication or fluid from entering the anterior (or proximal) cavity thereto. The piston 44, of course, travels together with the plunger member 14 and is physically secured thereto. Adjacent to the proximal end of the piston 44 is a seal section 52 of the enlarged piston portion which, similar to piston seal 34 or segment 22, provides a safety seal to prevent unauthorized access to the teeth. of ratchet 28 and immobilizer spring 40. It is also prevented that a paper clip, the tip of a knife, etc., have access to the proximal space of the piston. The diameter of the section 52 is approximately that of the inner side wall of the cylindrical body 12. The immobilizing spring 40 is best seen in Figures 9, 10 and 11. In the preferred embodiment, upon being formed, its basic configuration is that of a hollow figure with six sides with one side open. The overall shape is practically semi-cylindrical and extends around the plunger by approximately 200 °. Preferably, the spring is formed from a thin piece of resilient metal, preferably a single sheet and of stainless steel thickness. The material must be resilient so that it can be dispersed (by the manufacturer) for initial placement around the particular selected ratchet tooth 30, and still be placed on the plunger member, the immobilizing spring 40 spring back towards its dimensions origínale and its original configuration. The resilience also allows the locking spring 40 to flex radially inwardly and outwardly, after being secured around the plunger member and received inside the barrel. The immobilizing clip is installed on the plunger rod by pressing the open end onto a ratchet tooth, thereby temporarily expanding its front walls 70 and 72. After its initial placement, the spring member can no longer be dislodged from the plunger, due to the dimension of the open end of the immobilizing clip in comparison with the diameter DI of the ratchet tooth of the plunger. In an alternative version, due to the limited space between the plunger and the inner side wall 17, occupied by the immobilizing clip 40, this is secured around the plunger even when it extends less than 180 ° around the plunger. The dimensioning of the immobilizing spring 40 is such that the distance between the edges of the front walls 70 and 72 is smaller than the diameter of one of the ratchet diameters DI. It will be appreciated that the spring of the immobilizer 40 extends, in one embodiment, around at least 180 ° of the plunger member 14, so that after placement it can not accidentally fall off the plunger member. In fact, in the preferred embodiment, it extends approximately 200 °. As an alternative embodiment, when the syringe is constructed to provide 0.1 cc of medicament, the immobilizer clip may be circumferentially smaller. It has been determined that the minimum is approximately 27 ° around the plunger. In a preferred embodiment of the invention, the height h of the immobilizing spring 40 is smaller than the overall width w when formed. In this way, the immobilizing spring has more disk appearance and is not elongated. Therefore it is easier and less expensive to manufacture it than an elongated device since it requires less material and can be made with high speed manufacturing devices. The drawings show the immobilizer spring in the extended form in approximately 2 ratchet teeth (See Figures 1 and 2) only to facilitate its illustration. In real manufacturing, the height of the immobilizer dock is intended to be lower. The immobilizing spring has a flat rear section 60 and a pair of sidewalls 62 and 64 that extend outward and are opposite, secured to the side edges of the rear section. Extending inwardly from the outermost edges 66 and 68 of the side walls 62 and 64, respectively, are the front walls 70 and 72. Each of the rear section 60 the side walls 62 and 64 are of rectangular configuration. The front walls 70 and 72 have edges at angles 71 and 73 respectively (see Figure 9). The front vertical edges 74 and 76 of the front walls 70 and 72, respectively, are separated by a distance which, as already mentioned, is smaller than the diameter DI of the base 32 of the ratchet teeth 28. In this form, such as mentioned, the immobilizing spring 40, during manufacture of the syringe, can expand outwardly on and around a selected ratchet tooth 30, and still, when the forward vertical bardes 74 and 76 pass over the diameter Di of a base 32 of the plunger, the resilience of the immobilizer spring forces it to assume its original dimensions. In this way, the spring will not fall accidentally or withdraw from the plunger member unless a physical force is deliberately applied to it. As already mentioned, in the alternative embodiment of the invention wherein the immobilizing clip is less than 180 °, still extending below about 27 ° for syringes of 1 cc size capable of administering doses as low as 0.1 cc, the clip Immobilizer can not be removed from the plunger after insertion into the barrel since the interior space of the barrel is consumed by plunger and clip. The clip therefore can not move away from the plunger. On the contrary, it is sandwiched between the inner wall 17 and the plunger. An upper edge 78 extends along the rear section 60. Extending upward from the upper edge 78, in a substantially centered manner along the rear section 60, is a tab 80. The tab 80 has an edge 82 configured so that it can touch the outer edge of the base 32 of a ratchet tooth. The tongue 80 is coplanar with the rear section 60. The tongue that touches the edge of the plunger teeth prevents oscillating movement of the clip on the plunger during the movement thereof, and ensures alignment between the clip and the plunger. The tongue prevents clogging. Directed proximally and inwardly, the cam teeth 83 and 85 extend upwardly from the front walls 70 and 73, respectively. The immobilizing spring 40, when placed on the plunger, is free on the selected ratchet tooth. The inward angled cam allows the clip to move distally during an administration run. More specifically, they remain in contact with the base 32 of the ratchet tooth and the clip is pushed distally as the plunger moves distally. Clearances 91 and 93 are free spaces of flexibility control that modify the flexibility of the cam teeth. The upper edges 87 and 89 will initially rest on the inclined surface 31 of the ratchet tooth. The upper edges 87 and 89, during the distal movement of the plunger, they will strike below the base of a ratchet tooth so that the distant movement of the plunger leads to the clip together with the plunger. In addition, the resilience of the teeth 83 and 85 allows, by radially flexing the spring, the teeth to make a cam movement and ride on the inclined surfaces 31 of the ratchet teeth of the plunger, as the plunger moves in proximally, when the immobilizing spring is held in position within the barrel by the action of the locking teeth 84, 86, 88 and 90 embedded within the inner side wall 17 of the barrel. The movement of the piston 14 in the distal direction forces the immobilizing spring to move with it since a base 32 of a ratchet tooth pushes on the upper edges 87 or 89 of the cam teeth 83 and 85. However, the resilience of the immobilizer spring 40 allows the plunger to move proximally relative to the stationary immobilizer spring containment position 40 since the cam teeth will move with camming or ride on inclined surfaces 31. Extending proximally and out from the upper edge of the side walls 62 and 64 are the locking teeth 84, 86, 88 and 90. The locking teeth 84 and 86 extend from the side wall 62 and the locking teeth 88 and 90 extend from the side wall 64. Sections 95 and 97 lead to the locking and embedded teeth 84, 86, 88 and 90 and serve to reinforce their action. The flexibility control clearances 99 and 101 provide control of the flexibility of sections 95 and 97. The locking teeth are triangular in shape and terminate at contact points 105, 107, 109 and 111. The contact points extend outwardly. from the outer planar surface of the side walls 62 and 64 and, in fact, the immobilizing points are brought into contact with the inner side wall 17 of the cylindrical body 12. They are supported against the side wall. The hardness of the contact points is greater than the hardness of the lower side wall 17 of the cylindrical body 12, so that the contact points are buried and embedded within the inner surface of the side wall of the cylindrical body when the immobilizing spring 40 try to move around the plunger in the proximal direction. The outward radial resilience of the spring embeds the contact points within the side wall 17. When this proximal movement is attempted, the contact points prevent the immobilizing spring from moving proximally. The immobilizing spring may move distally as the contact points flex radially inwardly and slide on the inner side wall 17 during movement of the plunger in the distal direction. The shape and resilience of the devices allows the radial bending movement discussed. The distance between the contact points 105 or 107 and 109 or 111 may be less than the inner diameter of the side wall of the cylindrical body 12, and as the contact points extend outwardly relative to the outer planar surface of the walls 62 and 64, all contact points 105, 107, 109 and 111 are expected to make contact with the inner side wall 17 of the cylindrical body 12. The use of several contact points ensures the embedding of the immobilizing clip, even if there is irregularities of tolerance to the internal side walls 17 of the barrel.

A semicircular tongue 110 extends distally from the rear 60. It counterbalances the tongue 80 and also prevents jamming of the clip during the movement of the plunger. It extends, ie bends radially towards the plunger, at or around the edge 112. The tongue 110 provides for the smooth distal movement of the plunger and the clip without scraping the inside of the barrel. When the plunger is fully moved in the distal direction, the tongue 110 is actually forced between the plunger seal 52 and the side wall 17, further immobilizing the clip at the distant location. The construction, manufacture and use of the device are the following: the body is formed in the same way and with the same materials that are currently used in relation to conventional medical syringes. The plunger member 14, with its ratchet teeth and seals 34 and 52, is preferably formed as a single molded plastic product. In the preferred embodiment, the plunger is formed of a plastic having an additive to provide brittle properties. The rubber piston 44 is connected to the piston. The manufacturer determines the maximum dose for a particular lot of syringes. The manufacturer makes the selection, whether it is to decrease the size of the spring barrel for a particular maximum dose and / or adjust the location of the immobilizer spring clip on the plunger rod to be used in a syringe of more standard size. With the maximum dose in mind, the immobilizing spring 40 will be placed on the ratchet teeth 30 corresponding to the maximum desired dose. The individual ratchet teeth can be marked or printed during molding with suitable identification markings that facilitate the manufacture of the immobilizing spring 40 around the particular ratchet teeth lt corresponding to a particular maximum dose. The positioning of this is achieved by expanding the vertical cam edges 74 and 76 of the walls 70 and 72 on the base 32. The location of the immobilizer spring 40 towards the distal end of the plunger member 14 provides a smaller maximum dose for the syringe than the positioning of the same spring member 40 toward the proximal end. During the placement of the clip, the edges 74 and 76 of the immobilizer clip expand physically so that the distance between them becomes greater than the diameter DI of the base 32 of the ratchet teeth. This is achieved by the resilience of the spring clip in the radial direction. Placed in this way, the clip does not hold firmly against the plunger, but rather the cam teeth 83 and 85 touch the inclined surface 31 so that the immobilizing clip is free of a ratchet tooth. When the leading edges pass from the diameter DI of the plunger member with ratchet teeth, the resilience of the locking spring forces the edges 74 and 76 to assume their original dimension again, thus, it should be appreciated with those with ordinary skill in this. field, that the immobilizing spring 40 is placed around the plunger member so that the locking spring can not be easily removed without applying a physical force to again separate the edges 74 and 76. The locking spring is held on the plunger by a configuration greater than 180 ° and by the cam teeth 83 and 85 resting on the inclined surface 31 of the ratchet teeth. The immobilizing spring does not hold a ratchet tooth but is held loosely on the inclined surface of the tooth. The upper edges 87 and 89 of the teeth 83 and 85, as mentioned, are projected or bent inwardly by a sufficient distance so that they are supported against the inclination 31 or touch the same, of the particular ratchet tooth. The immobilizing spring 40 can not move proximally relative to the plunger member 14 since the relative movement is blocked by the mechanical interaction of the upper edges 87 and 89 of the cam teeth below the base of the adjacent ratchet tooth. upwards. With the immobilizer spring located in the desired position, the manufacturer completes the assembly process by securing the plunger member 14 together with the immobilizing spring 40 within the cylindrical body or barrel. The resilience of the spring allows the plunger and the clip to be inserted into the barrel. The item is then packed and delivered to the end user. Upon receipt by the user, the syringe 10 is removed by its packaging. In a conventional manner, the needle 15 is inserted into the vial of the medicament and the thumb contact disc 20 moves proximally relative to the grip 26 for the fingers. During the retraction of the plunger or proximal movement, the immobilizing spring 40 will be fixed in the barrel, a consequence of the radial flexing outwardly of the immobilizing spring which thus incrustates the teeth within the side walls. The spring can move proximally until the upper edge of the seal 52 comes into contact with the lower edge 112 of the immobilizing spring 40. Once this stop is presented, further proximal movement of the plunger member 14 can no longer occur. as the contact points 105, 107, 109 and 111 of the locking teeth 84, 86, 88 and 90 are physically buried in the inner side wall 17 of the cylindrical body 12. It should be appreciated by those with ordinary skill in this field that the spring Immobilizer 40 can not move when plunger member 14 moves proximally. The contact points prevent any proximal movement of the immobilizing spring. The initial location of the immobilizing spring and thus of the locking teeth 84, 86, 88 and 90 relative to the plunger determines the maximum amount of relative reciprocation of the plunger in the barrel and thus the maximum dosage that can be delivered by the syringe. During proximal movement of the plunger, the tongue 80 and the tongue 110 of the locking spring slide or cam over the edges of the ratchet teeth. Together, they maintain alignment and prevent clogging of the device. A plunger member 14 is removed or moved proximally relative to the cylinder body 12, the radial resiliency of the teeth of the locking spring 40 is such that the edges 87 and 89 will travel on each inclined surface 31 of each ratchet tooth 30. As the locking spring is held within the cylindrical body 12 in a relative position by the interaction of the contact points 107, 109 and 111 against the inner cylindrical surface 17 of the cylindrical body 12, the plunger member 14 can be completely withdrawn towards that section of seals 52 is brought into contact with the lower edge 112 of the immobilizing spring 40. When this occurs, further proximal movement of the plunger member 14 is mechanically blocked since further desired proximal movement of the plunger will only additionally embed the contact points to the interior of the inner side wall 17 of the cylindrical body 12. Thus, the plunger member is restricted in its relative movement with respect to the cylinder body. With the medicament now contained within the cylinder body 12, more specifically between the piston 44 and the tip 18 of the cylindrical body 12, the user is ready to administer the medication through the needle 15, as and when desired. The needle is inserted through the skin of the patient and the user applies pressure to the thumb contact disc 20, so that the plunger member 14 moves distally, thereby pushing the piston 44 distally, and this way administering all the medication through the tip 18 and the needle 15. As the upper edges 87 and 89 of the cam teeth 83 and 85 will be pushed distally by the contact with the base 32 of the located ratchet teeth above, the flexure spring 40 will flex radially inwardly and slide distally into the barrel, as the plunger member 14 moves distally to deliver the medicament. The contact points only prevent the proximal movement of the immobilizer spring; distal movement is allowed by the sliding of the contact points along the inner side wall and the inherent resilience of the immobilizing clip. After the medicament has been administered from the syringe, the seal 52, above the piston 44, abuts against the inner edge 112 of the immobilizing clip. A second reciprocation of the plunger member 14 relative to the cylindrical body 12 is mechanically blocked since the locking spring 40, adjacent seal 52, will be embedded within the side wall 17 as it is attempted to move the plunger proximally. A second proximal movement is prevented by the contact points 105, 107, 109 and 111 which are buried in the inner side wall 17 of the cylindrical body 12. Thus, it will be evident that a second reciprocation to introduce medicine or drugs into the syringe 10 is left. mechanically locked as the plunger member 14 can not move a second time in the proximal direction with respect to the cylindrical body 12. To further incapacitate the syringe 10 for a subsequent potential use, the user can, if desired, bend or twist the disc 20 of contact with the thumb along the fracture plane 24 until it breaks. Without the thumb contact disc 20 secured to the plunger member 14, it is much more difficult to reciprocate the plunger member 14, in any direction, even assuming that one could first incapacitate the immobilizing spring mechanism. Furthermore, the thumb contact disk 20 can now serve as a means of limiting the distribution of the syringes. For example, a number of these discs can be collected and returned to the manufacturer or dispatcher as a trade for a similar number of movements. syringes Inventory and audit control is easier to track with flat discs than with the entire bulky syringe assembly. In an alternative embodiment of the present invention, the thumb contact discs are provided (See Figure 12) with a thumb section 120 which is inclined and a second disc-like section 122, with an inclined outer wall. Together, these comprise an arrangement similar to a male annular dovetail for the plunger. The proximal portion of the cylindrical body 12, adjacent the finger grip 26, is provided with an edge 130 directed inwardly each year, terminating in an immobilizing flange 132.

Together they comprise an arrangement similar to an annular female dovetail for the barrel. In this way, when the thumb contact disk 20 is fully reciprocated in the distal direction, the sloping outer wall 122 slides until the locking flange 132 overlaps the second annular disk-like section 122, thereby avoiding any proximal or distal movement of the plunger relative to the cylindrical body 12. In this way, it will be appreciated and will be apparent to those with ordinary skill in this field, that the smallest diameter of the rim 130, at the point of the locking flange 132, is less to the larger diameter of the rim surface 134, although the resilience of the barrel and a gap at the proximal end allow the rim 130 to be movable as a cam on the rim 134 until it is supported by the immobilizing rim 132. In an alternative embodiment of the invention a mechanism is provided to prevent the violation of the immobilizing mechanism. After the first distal movement of the plunger, the immobilizing clip is embedded within the side wall of the syringe adjacent to the seal 52. The distal force that is needed to overcome the force of the immobilizing clip that is embedded in the side wall of the barrel it exceeds the tensional resistance of the plunger, so that a second attempt of proximal movement will result in the separation of the physical separation of the plunger along its length, preferably just above the immobilizing clip (see Figure 4). To locate the sectioning at that location, a section of reduced diameters 114 of the plunger is placed above the seal section 52. In the preferred embodiment, the reduced cross-sectional area of the plunger is positioned so that the rupture is presented just above the proximal surface of the clip. As seen in Figures 6, 7 and 8, two or more reduced areas 114 and 116 are provided as potential areas to be sectioned by the movement of the plunger. As best seen in Figure 11, the radial resilience and the resistance of the immobilizing clip causes the plunger to move and exit the axial alignment with respect to the barrel axis. In this form, in syringes of very small diameter and volume, an immobilizing clip can be provided with utilization blocking functions. Only a simple thickness of metal is required through a barrel diameter between the plunger and the side wall of the barrel, In an alternative embodiment, as the clip is not acting symmetrically around the plunger, but asymmetrically, the clip Immobilizer can be as small as 27 ° of the 360 ° of the plunger. In this way, syringes of very small capacity can be achieved with an immobilizing mechanism that prevents reuse. The vector forces of the immobilizing teeth push the plunger out of alignment. The various embodiments of a single-use hypodermic syringe and needle unit have been described. While the invention has been described in relation to the specific embodiments, the description is illustrative of the invention and should not be interpreted in a limiting sense. Various modifications and applications may be made to the experts in this field without thereby departing from the true spirit and scope of the invention.

Claims (46)

1. CLAIMS 1. A disposable syringe comprising: a hollow barrel having an inner cylindrical side wall, a needle point at the distal end of the barrel and a proximal end opposite the needle tip end of the barrel; a plunger rod having a longitudinal axis placed inside the barrel for axial movement therein, for introducing fluid into the interior and expelling fluid out of the barrel, through the water point, the plunger rod extends beyond the barrel at the proximal end and has a seal piston at the needle tip end; a immobilizer clip, radially resilient, mounted on the plunger rod, the immobilizer spring clip has a plunger coupling means and at least one outwardly locking immobilizer tooth having a point of contact, the plunger coupling means is in contact with the plunger rod and the contact point is in contact with the side wall; the plunger rod is free to move a first time towards the proximal end of the barrel, the immobilizing spring clip is held in position by the frictional engagement of the contact point against the side wall as the plunger rod moves proximally , and still, the distal movement of the plunger rod causes the plunger coupling means to move the immobilizing clip together with the plunger rod in the distal direction; whereby the immobilizing spring clip allows the syringe to be loaded with medicament in the volume of the barrel defined by the predetermined location of the immobilizing spring on the plunger rod, by the proximal movement of the plunger, and after the distal movement of the rod of the plunger. Plunger for expelling the medicament, a second proximal movement of the plunger rod is prevented by the frictional coupling between the contact point and the inner cylindrical side wall. A single use syringe according to claim 1, wherein the plunger coupling means comprises a contact point directed towards the plunger rod. 3. A disposable syringe according to claim 1, wherein the immobilizing spring clip extends approximately 200 ° around the plunger rod. 4. A disposable syringe according to claim 1, wherein the immobilizing spring clip extends approximately 180 ° around the plunger rod. 5. A disposable syringe according to claim 1, wherein the immobilizing spring clip extends less than 180 ° and more than about 27 ° around the plunger rod. 6. A disposable syringe according to claim 1, wherein the volume of the barrel defined by the position of the immobilizing clip on the plunger rod and the piston is as low as approximately 0.1 cc. 7. A disposable syringe according to claim 1, wherein the barrel has a maximum capacity of about 0.1 cc. • A disposable syringe according to claim 1, wherein the immobilizer spring clip is made of metal. 9. A disposable syringe according to claim 1, wherein the immobilizing spring is made of stainless steel. 10. A disposable syringe according to claim 1, wherein the immobilizing spring clip forces the plunger rod to be out of axial alignment with respect to the hollow barrel. 11. A disposable syringe according to claim 1, wherein the distance between the axes of the immobilizing spring clip and the contact point, when the immobilizing spring is removed from the plunger rod, is slightly greater than the radius of the cylindrical lateral wall inside. 12. A disposable syringe according to claim 1, wherein the plunger rod is provided with seal means to prevent unauthorized access to the ratchet teeth and the immobilizing spring. 13. A disposable syringe according to claim 11, wherein the limit of the proximal movement of the plunger rod is controlled by the stop between the seal means and the immobilizing spring. 14. A disposable syringe according to claim 1, wherein the immobilizing spring clip flexes radially inwardly and outwardly during movement of the plunger rod. A disposable syringe according to claim 1, wherein the seal means is provided both at the distal end and at the proximal end of the plunger rod to prevent unauthorized excess to the ratchet teeth and to the spring immobilizer 16. A disposable syringe according to claim 1, wherein the immobilizing spring clip is a multi-sided, open-ended, hollow figure. 17. A disposable syringe according to claim 14, wherein the dimension of the open end is smaller than the diameter of the base of the ratchet teeth. 18. A disposable syringe according to claim 1, wherein the immobilizer spring clip is substantially semi-cylindrical. 19. A disposable syringe according to claim 1, wherein the side wall is rough. 20. A disposable syringe according to claim 1, wherein the plunger rod is provided with a thumb contact disc which is intended to break and separate from the plunger rod after single use. 21. A disposable syringe according to claim 18, wherein the disc is separated from the plunger rod in a fracture plane of reduced diameter. 22. A disposable syringe according to claim 1, wherein the plunger rod is provided with at least one region of reduced diameter, smaller than the diameter of the ratchet teeth. 23. A disposable syringe according to claim 1, wherein the region of reduced diameter is placed in close proximity to the piston. 24. A disposable syringe according to claim 1, wherein the region of reduced diameter is positioned just above the immobilizing clip after the plunger has moved first proximally and fully distally. 25. A disposable syringe according to claim 1, wherein the plunger rod is provided with a thumb contact disk having an annular dovetail configuration which cooperates and immobilizes a female dovetail opening. at the proximal end of the barrel, so that the completely distal movement of the plunger rod with respect to the barrel immobilizes the plunger within the barrel. 26. A disposable syringe according to claim 1, wherein two or more contact points are provided in the immobilizer spring clip. 27. A disposable syringe according to claim 1, wherein the barrel is provided with a visual calibration scale. A disposable syringe according to claim 1, wherein the immobilizing spring clip is provided with an alignment tab, which rides on the edges of the ratchet teeth to ensure that the immobilizing spring clip does not become jammed during assembly distal of the plunger. 29. A disposable syringe according to claim 1, wherein the tensional resistance of the plunger is less than the frictional force that embeds the point of contact of the immobilizing clip within the side wall. 30. A disposable syringe according to claim 1, wherein the ratchet teeth are marked with means indicating the dose. 31. A disposable syringe according to claim 1, wherein the maximum capacity of the syringe is 1 cc. 32. A disposable syringe according to claim 1, wherein the immobilizing spring is a metal sheet of a single thickness. 33. A disposable syringe according to claim 1, wherein the plunger material is made of brittle material. 34. A disposable syringe according to claim 1, wherein the immobilizing spring comprises a hexagonal open ended shape., where the opening is smaller than the diameter of the base of the ratchet teeth. 35. A disposable syringe according to claim 1, wherein the alignment tab is located centrally on the immobilizing spring and opposite pairs of the contact points are placed on both sides of the tab. 36. A single use syringe according to claim 1, wherein the thickness of the immobilizing spring clip material through all the diameters of the barrel is only one thickness. 37. A single use syringe according to claim 1, wherein the dose of the syringe is limited by the distance that the piston can travel until it abuts the distal edge of the immobilizing spring. 38. A disposable syringe according to claim 11, wherein the seal means provides uniform pressure to the base of the immobilizing spring clip. 39. A disposable syringe according to claim 11, wherein the immobilizing spring clip is further provided with an alignment and anti-jamming feature comprising a first tongue directed distally and a second tongue directed inwardly and inwardly. proximal 40. A disposable syringe according to claim 39, wherein the second tongue is substantially semicircular. 41. A disposable syringe according to claim 1, wherein the plunger rod is comprised of one or more frustoconical ratchet teeth. 42. A disposable syringe according to claim 1, wherein the plunger rod has two or more frusto-conical ratchet teeth. 43. A single use syringe according to claim 41, wherein the plunger coupling means comprises at least one inwardly directed ratchet tooth engaging a cam tooth. 44. A single-use syringe according to claim 43, wherein the cam tooth flexes radially on the surface of the ratchet tooth as the plunger rod moves proximally. 45. A single use syringe according to claim 43, wherein the cam tooth engages the base of a ratchet tooth when the plunger rod moves distally. 46. A disposable syringe according to claim 43, wherein the immobilizing spring is provided with a space of flexibility between the cam teeth and the contact point.