US20060264744A1 - Method and Apparatus for Injecting Fluid into Animals and Disposable Front Loadable Syringe Therefor - Google Patents

Abstract

An animal fluid injector replaceable syringe and method of replacement of the syringe in the injector are provided in which the syringe is loadable and unloadable into and from the injector through the front of the injector, thereby permitting replacement without retraction of the syringe plunger drive or disconnection of the injection tubing. A mechanism in the injector, which includes, for example, a key on cam ring operated by a lever with one hand of an operator, interacts with structure such asymmetrically spaced notches on the back end of the syringe to, for example, rotate the syringe and simultaneously translate or rotate a coupling on the syringe plunger into and out of engagement with jaws of the plunger drive in the injector.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This application is a divisional of application Ser. No. 10/730,302 filed Dec. 8, 2003, now U.S. Pat. No. 7,081,104, which is a divisional of application Ser. No. 09/970,289 filed Oct. 2, 2001, now U.S. Pat. No. 6,659,979, which is a divisional of application Ser. No. 08/924,017, filed on Aug. 29, 1997, now U.S. Pat. No. 6,315,758, which is a continuation of Ser. No. 08/455,984 filed May 31, 1995, now U.S. Pat. No. 5,738,659, which is a continuation of Ser. No. 08/158,765 filed Nov. 30, 1993, now U.S. Pat. No. 5,456,669, which is a divisional of Ser. No. 07/881,782 filed May 11, 1992, now U.S. Pat. No. 5,279,569, which is a divisional of Ser. No. 07/712,110 filed Jun. 7, 1991, now U.S. Pat. No. 5,300,031, all of which are hereby incorporated by reference herein.
FIELD OF THE INVENTION
• The present invention relates to injectors and more particularly to disposable replacement syringes for animal fluid injectors.
BACKGROUND OF THE INVENTION
• Injectors are devices that expel fluid, such as contrasting media, from a syringe and through a tube into an animal. The injectors are provided with an injector unit, usually adjustably fixed to a stand or support, having a drive that couples to the plunger of the syringe to drive it forward to expel fluid into the tube, or that may be driven rearward to draw fluid into the syringe to fill it. Usually the syringe is a disposable replacement type.
• In the injection phase where the plunger is driven forward, pressures are developed in the syringe that range from, for example, twenty-five psi for some applications to over 1000 to 1200 psi for other applications. Syringes that will contain fluid under such pressures are expensive and therefore impractical where the syringes are to be disposable. Accordingly, many such injectors, such as angiographic injectors, for example, have been provided with pressure jackets fixed to the injector units and into which the syringes are inserted. The pressure jackets contact the outer surfaces of the syringe to restrain the walls of the syringe against the internal pressures.
• To hold the syringes in the pressure jackets, the jackets of the prior art have been configured to surround the front ends of the syringes to restrain the syringe front wall against forward acting forces of the drive and the fluid pressure and to hold the syringe in the jacket. Because the front end of the pressure jacket is closed, rear loading was necessary, and accessibility thereto was provided by hinging or rotating the jacket to allow for removal and replacement of the syringe from the rear. The opening and reclosing of the injector unit to replace the syringe requires a certain amount of time, which, in the course of the procedure being performed, is not wholly desirable.
• Furthermore, while for many years injector units of various types have been capable of disconnection of the plunger drive from the drive coupling on the syringe plunger at any position of the plunger within the syringe, retraction of the drive is typically required before the syringe can be removed. This is because the opening of the injector unit to remove and insert the syringe from the rear requires, for example, a translating or rotating of the jacket from the axis of the drive, which cannot be achieved if the plunger drive is extended.
• For example, at the end of an injection procedure, the syringe plunger typically is forward, as is the plunger drive. Since, in the prior art injectors that load from the rear, the pressure jacket is moved through the position that the drive occupies when extended in order to remove the syringe. Hence, the syringe cannot be immediately removed without retracting the plunger drive. Further, the disposable tubing that connects to the nozzle of the syringe must be disconnected from the syringe in order to remove the syringe from the jacket. Additionally, when an empty new syringe is inserted, the drive must be in its retracted position.
• More often than not, the syringe is inserted empty and filled by retraction of the plunger with an injection tube connected to a supply of the fluid that is to be injected. In addition, before an empty new syringe can be filled, it is necessary that the plunger be fully forward in the syringe so that the syringe can be filled by rearward retraction of the plunger. As a consequence of the need with such prior art injectors to retract the drive upon loading the syringe, it is then necessary to fully advance the drive to the position in which it is in engagement with the plunger and the plunger is in its full forward position. The drive then engages a coupling on the plunger of the replacement syringe. This need to retract and advance the drive contributes to a loss of time in the syringe replacement process.
• Accordingly, there has been a need to more quickly load and unload disposable replacement syringes in angiographic injectors, and for injectors and replacement syringes that can accommodate a more efficient process of syringe replacement.
SUMMARY OF THE INVENTION
• It is an objective of the present invention to provide a method and apparatus by which replaceable syringes can be more efficiently loaded into and unloaded from injectors.
• It is a more particular objective of the present invention to provide an injector, more particularly an angiographic injector, a replacement syringe therefor, and a method of replacing the syringe in the injector that provide for more efficient replacement of the syringes in the injector. It is an additional objective of the present invention to provide an injector wherein a used syringe can be removed and a new one inserted in the injector without retraction of the drive from the pressure jacket, in most applications. It is a further objective of the invention to allow for the removal of the used syringe from the jacket without disconnection of the injector tube from the syringe nozzle.
• It is still a further objective of the present invention to provide an injector, replaceable syringe and method of syringe replacement with which the replacement of the syringe can be achieved with simple motions by the operator or with rapid operation of injector unit mechanisms.
• An additional objective of the present invention is to provide an injector and replaceable syringe therefor that will facilitate control of the orientation of the syringe in the jacket, and thereby provide for positive, rapid and reliable engagement of the syringe with locking structure that holds the syringe in the jacket, engagement of the plunger drive and plunger drive coupling, or connection of the injection tube to the outlet of the syringe.
• A further objective of the present invention is to provide for easy to operate mechanism and reliable locking structure for locking the syringe in place in the pressure jacket of the injection unit.
• Another objective of the present invention is to provide an injector and syringe arrangement that minimizes or eliminates the probability of spillage from the syringe nozzle flowing into the injector equipment, and otherwise enhancing the ability to maintain sterility and cleanliness of the equipment.
• According to the principles of the present invention, there is provided an angiographic injector having a front end loadable syringe that can be loaded into and removed from the injector pressure jacket through an opening that is provided in the front end of the pressure jacket. To provide this front end loadable feature, the syringes of the preferred and illustrated embodiments of the present invention are provided with a front wall that is pressure restraining, that is, is of sufficient strength to support the front of the syringe against the expected pressures within the syringe, and that is securable to the front end of the pressure jacket so as to complete the pressure restraining enclosure of the syringe within the pressure jacket and hold the syringe in the jacket. In one preferred form, this front end of the injector is formed of a separate pressure restraining cap made of material that is separate from the front wall of the syringe and may be reusable. In another preferred form, the cap may be formed integrally of the front syringe wall. With the cooperating structure of the jacket and the syringe, restraining of the pressure jacket along the front and sides of the syringe is provided where the jacket allows for the replacement of the syringe from the front.
• In one preferred and illustrated embodiment of the invention, the front end of the syringe locks to the front end of the pressure jacket through a cooperating engagement of mating threads on the syringe jacket. The threads include external thread sections formed at the front end of the pressure jacket and internal threads formed on an outwardly extending flange or rim of the front wall of the syringe, preferable on a pressure restraining cap. Alternatively, other securing or locking structure such as a clip or an adaptor, for example, may be employed to join the syringe to the jacket.
• In the preferred embodiment of the present invention, the threads are engageable in a limited number of angular positions to thereby predetermine the angular orientation of the syringe in the pressure jacket. Additionally, other keys and keyways carried respectively by the unit and by the syringe limit the angular position in which the syringe may be inserted into the jacket to a unique predetermined angular orientation. Preferably, three keyways, such as slots or notches, unequally spaced around the back, rearward or proximate edge of the syringe body, engage similarly spaced keys or tabs on the unit at the rear end of the pressure jacket to permit insertion of the syringe into the jacket in one and only one orientation.
• Further in accordance with principles of the present invention, in its preferred embodiment, a coupling on the syringe plunger is centrally located and symmetrical about the axis of the plunger. A pair of jaws on the plunger drive is moveable either by transverse straight or arcuate translatory motion or by forward longitudinal motion to form a connection between the coupling and the drive. Once coupled to the drive, the coupling remains engaged to the drive during longitudinal motion of the drive to cause the plunger to move forward or backward with the drive. Disengagement occurs thereafter only upon transverse translational motion of the plunger with respect to the drive. In certain embodiments, this translatory transverse motion occurs by translatory movement of the jacket, and the injector unit door that carries the jacket, with respect to the plunger drive and the unit housing. In other embodiments, an asymmetrical coupling is provided that engages and disengages the plunger drive upon rotational movement of the syringe with respect to the drive.
• Preferably, the motion for locking the syringe to, and unlocking the syringe from, the jacket is achieved by rotation of the syringe in the jacket, and preferably, this motion is linked to, and occurs simultaneous with, the motion that engages and disengages the plunger coupling and drive, whether that coupling is by translation or rotation. In addition, the syringe and plunger drive are so dimensioned and positioned to prevent contact between the drive and the sterile interior wall of the syringe, regardless of the position of the drive, as the syringe is being loaded.
• Preferably, the syringe is formed of a cylindrical body, with the front end in the shape of a truncated cone that terminates in a forwardly extending neck with an orifice at its remote end that is connectable with an injection tube. The front end of the syringe is shaped so as to direct fluid leaking from the nozzle outwardly around the front end of the jacket. This prevents leakage, which often results upon disconnection of the injection tubing, from entering the space between the pressure jacket and the syringe body.
• Replacement of the syringe begins, in the preferred embodiments of the invention, with the unlocking the syringe at its front end from the front end of the pressure jacket, preferably by rotating the syringe with respect to the jacket, and by disengaging the plunger drive from the syringe plunger, alternatively by transverse translational or rotational motion, preferably simultaneous with and linked to the motion that disengages the syringe from the jacket. The unlocking of the syringe from the jacket occurs, for example, by loosening mating threads at the front of the syringe and jacket. The twisting of the syringe in the jacket is linked to motion that either translates transversely or rotates a coupling on the syringe plunger out of engagement with the plunger drive.
• Then the syringe is removed from the jacket through the open front end of the jacket. This removal may take place without retraction of the plunger drive, should the drive be advanced in the pressure jacket at the time of disengagement from the plunger coupling. The used syringe may also be removed without disconnection of the disposable injection tubing from the nozzle of the syringe.
• When the used syringe is removed, a replacement syringe is inserted into the jacket through its open forward end and the front end of the new syringe is locked to the front end of the jacket, preferably by relative rotation of the syringe in the jacket to cause, for example, engagement between mating threads on the front end of the syringe and the front end of the jacket. The plunger drive, in one embodiment, is translated to bring the plunger coupling engaging jaws into alignment with the plunger coupling, preferably simultaneously with the locking of the syringe to the jacket. The jaws thereby either engage the coupling upon the translatory motion, or thereafter engage the coupling by longitudinal advancement of the drive against the coupling. In one embodiment, the jaws are positioned off center of the drive so that the drive, whether in the engaging or the disengaging positions, does not contact a syringe as the syringe is guided by the jacket during loading.
• In an alternative embodiment, engagement of the plunger drive with the coupling occurs by relative rotation of the drive and the coupling, preferably by rotating the coupling relative to a stationary plunger drive, rather than by translational motion between the drive and the coupling. Only if the rest position of the plunger of the replacement syringe is behind the final position of the plunger drive at the time it was disconnected from the coupling of the plunger of the syringe being replaced need the plunger drive be retracted.
• The engagement and disengagement motions between the plunger drive and plunger drive coupling, and between the syringe and the pressure jacket, are provided with manually operable mechanism that, in the preferred and illustrated embodiments, rotates the syringe in the jacket and further either rotates or translates the coupling with respect to the plunger drive, with a simple one hand operated mechanism. The mechanism provides a convenient lever, operable through a short arc, to rotate the syringe in the jacket and to then, preferably, translate the pressure jacket that carries the syringe and is carried by the injector unit door, or to otherwise move the syringe with respect to the drive, to bring the plunger coupling of the syringe into or out of alignment with the plunger drive.
• The present invention provides a disposable syringe that may be replaced in an angiographic or CT injector with great efficiency and speed. Further, replacement may occur without retraction of the plunger drive of the injector unit. Simple and rapid one hand operation of the engaging and disengaging structure is provided.
• These and other objectives of the present invention will be more readily apparent from the following detailed description of the drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of an angiographic CT injector embodying principles of the present invention.
• FIG. 1A is a perspective view of an another form of angiographic injector embodying principles of the present invention.
• FIG. 2 is an exploded perspective view of a portion of one preferred embodiment of the injector ofFIG. 1.
• FIG. 3 is a perspective view of the portion of the injector ofFIG. 2.
• FIG. 4 is a cross-sectional view along lines4-4 ofFIG. 3 illustrating a replaceable syringe unlocked from the housing for insertion into or removal therefrom.
• FIG. 5 is a cross-sectional view similar toFIG. 4 but illustrating the syringe locked to the structure carried by the housing.
• FIG. 6 is a cross-sectional view along the line6-6 ofFIG. 5.
• FIG. 7 is an elevational diagrammatic illustration of the injector ofFIG. 1 with the pressure jacket and syringe removed, and showing the syringe locking structure in the locked position such as inFIGS. 5 and 6.
• FIG. 8 is an elevational diagrammatic view similar toFIG. 7 illustrating the syringe locking structure in the unlocked position such as inFIGS. 2-4.
• FIG. 9 is an elevational diagrammatic view similar toFIG. 7 illustrating the locking mechanism in the housing door release position.
• FIG. 10 is a cross-sectional view through the housing of the injector taken along lines10-10 ofFIG. 1 with the plunger drive disengaged from the syringe plunger coupling.
• FIG. 11 is a view of a portion ofFIG. 10 illustrating the plunger drive longitudinally moving into engagement with the plunger coupling.
• FIG. 12 is a view of a portion ofFIG. 10 illustrating the plunger drive in engagement with the plunger coupling.
• FIG. 13 is a front view of a portion of another embodiment of the injector ofFIG. 1.
• FIG. 14 is a view of an alternative embodiment of a portion of a syringe according to principles of the present invention.
• FIG. 15 is a cross-sectional view similar toFIG. 5 of an alternative embodiment of the invention, illustrating alternative engaging structure between the front ends of the syringe and jacket.
• FIG. 16 is a cross-sectional view similar toFIG. 5 of a further alternative embodiment of the invention, also illustrating alternative engaging structure between the front ends of the syringe and jacket.
• FIG. 17 is a front end view of still a further alternative embodiment of the invention, also illustrating alternative engaging structure between the front ends of the syringe and jacket.
DETAILED DESCRIPTION OF THE DRAWINGS
• Referring toFIG. 1, an angiographic injector10 according to another preferred embodiment of the present invention is illustrated, configured for CT applications. The injector10 includes a ceiling mounted support11, adjacent a CT X-ray unit, to the lower surface of which is rigidly supported a vertically descendingsupport column12.
• Remote from the support11 is an injectorcontrol module console13 behind a wall which isolates the operator area from the X-ray equipment. Theconsole13 is located adjacent a control14 of the X-ray equipment. Electrical power and control cables (not shown) communicate power and control signals through the support11 and thecolumn12 and to apower lead15. Theconsole13 connects with aninjector control module16, which includes a programmable microprocessor (not shown) to which commands and programming codes are input through a keyboard17 on theconsole13. Theconsole13 is also provided with anoperator display18 to aid in interfacing the input commands and injector status with the operator.
• Attached to thecolumn12 is an articulatingadjustable arm19. To the remote end of thearm19 is adjustably supportedinjection module unit20. Thearm19 is capable of setting theunit20 at varying positions adjacent a patient bed of the CT unit.
• Referring toFIG. 1A, anangiographic injector10aaccording to another preferred embodiment of the present invention is illustrated. Theinjector10aincludes awheeled base11ato the top of which is rigidly supported a vertically adjustableupstanding support column12a. To the top of thecolumn12ais supported acontrol module platform13a. Electrical power is communicated from a power cord (not shown) through the base11 and theupstanding support12aand through a power lead15ato a control module16arigidly supported to theplatform13a. The control module16aincludes a programmable microprocessor (not shown) to which commands and programming codes are input through akeyboard17aon the module16a. The module16ais also provided with an operator display18ato aid in interfacing the input commands and injector status with the operator. Attached to theplatform13ais an articulating adjustable arm19a. To the remote end of the arm19ais adjustably supported theinjection module unit20.
• Theinjection module unit20 of the embodiments ofFIGS. 1 and 1A includes ahousing21 which contains the operating drive structure of theinjector10 or10a. Thehousing21 has asupport bracket23 fixed thereto and adjustably pivotally supported to the remote end24 of the articulatingarm19 or19a. Thehousing21 has pivotally attached to the front thereof adoor25 at the front thereof which is pivotally connected to thehousing21 at a longitudinally extending pivot or hinge pin26 (FIG. 2) rigidly supported on thehousing21 and extending forwardly from the front of thehousing21.
• On the top of thehousing21 is an injector position and local control panel27 having aposition indicator scale28 thereon, which displays the position of the injector drive to the operator. The panel27 also includes a pair of forward and reverse drive direction control buttons29, which are selectively actuatable to activate a drive within thehousing21 in either the forward or reverse directions.
• Extending forwardly from the front of thedoor25 is an injector syringe andpressure jacket assembly30, the structure of which can be better understood with reference toFIGS. 2-5 below. The syringe andjacket assembly30 includes a hardplastic pressure jacket31, which may be of opaque or transparent material, a removable and replaceabledisposable syringe32, which may be of opaque, transparent or semi-transparent material, and related structure hereinafter described.
• Thesyringe32 is disposable, and includes walls which will withstand only moderate or low pressure. The walls are usually outwardly deformable under operating pressures, particularly pressures of 300 psi or more. Such higher pressures are necessary to overcome pressure drops through the injection tubing at higher flow rates, which are often desirable. Thejacket31 is made of a stronger transparent material that will withstand the operating pressures. When thesyringe32 is contained in thejacket31, it is surrounded by thejacket31 and supported by thejacket31 against expansion caused by the fluid pressure within as thesyringe32 expands against the jacket wall.
• Thepressure jacket31 has a generally cylindrical inner bore33 extending therethrough from aproximate end34 adjacent thedoor25 to aremote end35 of thepressure jacket31 toward the front of theunit20. Thebore33 is dimensioned so as to receive through theremote end35 thedisposable syringe32 and to support the syringe against expansion from fluid pressure within such fluid pressure may range to more than a thousand psi. Thepressure jacket31 has anannular flange37 extending outwardly around theproximate end34. Theflange37 is integrally formed with the jacket cylinder and is shaped to conform to anannular recess38 surrounding acircular hole39 in thedoor25 to which thejacket31 may be assembled by insertion from the rear. The hole or opening39 in thedoor25 and the cylindrical bore33 of thejacket31 are concentric with a longitudinal axis40 on which also lies anaxis41 of thesyringe32 when thesyringe32 is positioned in thebore33 of thejacket31. Thejacket31 is firmly and rigidly attached to thedoor25 with a pair ofscrews43, only one of which is shown, which are threaded into a pair of holes44 in the back of the door25 (FIG. 2). An O-ring seal46 surrounds theflange37 of thejacket31 in therecess38 of thedoor25.
• Thesyringe32 includes asyringe case50 formed of a single piece of molded plastic material, apressure cap51, a tubing collar52 (FIG. 3) and a plunger54 (FIGS. 3-5). Thesyringe case50 includes acylindrical syringe body55 having an openproximate end56 and aremote end58 to which is integrally formed a conicalfront wall57. Thefront wall57 is truncated at its forward end, to which is integrally formed anelongated neck59 extending from thewall57 at the center thereof. Theneck59 of thesyringe case50 has an orifice60 (FIG. 3) in its remote end which communicates with aninternal syringe cavity61 formed within theneck59, the conicalfront wall57 and thecylindrical body55 of thecase50 of thesyringe32. The rear end of thecavity61 is further defined by a forward facingconical surface64 of theplunger54. Theconical surface64 is of a slope which conforms to the slope of the interior of the conicalfront wall57. Theplunger54 is slidable within thebody55 of thesyringe case50 such that thecavity61 is of variable volume.
• Near the front end of theneck59 of thesyringe case50, just behind the orifice60, is anexternal thread66 configured to mate withthreads67 on the interior of collar52 (FIG. 3). Thethread66 in theneck59 has anstop69 at near forward end thereof to engage an abrupt step70 on thethread67 of thecollar52 so that, when thesyringe32 is properly oriented in thejacket31, thecollar52, when loosened to its maximum extent, will assume a predetermined orientation so as to present, in an upwardly facing orientation, a tubeend receiving slot62 formed in the remote end of thecollar52. Thisslot62 is of T-shaped cross-section so as to receive theenlarged flange end63 of atube65 through which fluid from thesyringe cavity61 is injected into a patient.
• Thecap51 is generally conical in shape and has an innerrearward surface75, which conforms to the front surface of theconical wall57 of thecase50 of thesyringe32. In certain embodiments, the rearwardconical surface75 of thecap51 may be bonded to the front surface of theconical wall57 of thecase50 of thesyringe32, or it may be formed integrally therewith, molded from the same plastic material as thecase50 of thesyringe32. In the preferred and illustrated embodiment, thecap51 is separate from thesyringe body portion55 and has a pair of holes ordetents76 into which fit a pair ofprojections77 extending forwardly from and formed integrally on the outer surface of theconical wall57 of thecase50 of thesyringe32. The cooperation of the pins orprojections77 with the holes ordetents76 prevent the cap from rotating with respect to thesyringe case50 when thecap51 is mounted on thesyringe32.
• To hold thecap51 against theconical wall57 of thecase50 of thesyringe32, sixresilient tabs78 are formed about a centralinner hole79 of thecap51. Thetabs78 are separated by six equally spaced radial slots80 (FIG. 3). Thehole79 in thecap51 is equal to or only slightly greater in size than the circular forward end of theconical wall57 of thecase50 of thesyringe32. Theneck59 of thesyringe32 has an enlarged straight section81 slightly greater in diameter than thehole79 in thecap51 and also greater in diameter than the forward end of theconical wall57 of thecase50, thereby forming agroove82 at the juncture of the straight neck portion81 with theconical wall57 so that the tips of thetabs78, which are sufficiently resilient to slide over the enlarged neck portion81 as thecap51 is inserted on thecase50 of thesyringe32 with thehole79 surrounding theneck59 to snap fit into thegroove82.
• Thesyringe32 includes structure that is configured to lock thesyringe32 to the front end of thejacket31 by cooperating with mating structure on thejacket31. Thejacket31 has, spaced around the circumference thereof near the remote orfront end35 of thejacket31, four equally spaced outwardly projectingthread sections85. Thesethread sections85 are slightly less than 45° in extension around the circumference of thejacket31 and are spaced apart with gaps of slightly greater than 45°. Thecap51 has acylindrical rim87 in which are formed four similarly sized and spacedmating thread sections86. Thethread sections86 project inwardly toward thejacket31 when thesyringe32 is positioned in thejacket31. As such, when thesyringe32, with thecap51 assembled to it is inserted into thejacket31, thethreads86 of thecap51 pass through the spaces between thethreads85 on thejacket31 to a point behind thethreads85. When so inserted, thesyringe assembly32 with thecap51 may be twisted clockwise 45° to tighten and thereby secure thecap51 to thejacket31 by engagement between thethreads85 and86 as shown inFIG. 5, to thereby lock the syringe in thebore33.
• Thepiston54 of thesyringe32 is molded of an elastomeric material. Preferably, thepiston54 includes two portions molded of different materials and bonded together. These portions include a forward moreflexible portion90 in which is formed the forwardconical surface34. Thisforward portion90 has a pair of outwardly extendingrings91 formed in the periphery thereof to make sealing engagement with the inside of the wall of thecylindrical body55 of thesyringe case50. The rearward portion of thepiston54 is a flat circular surface to which is bonded the flat circular forward surface of a more rigidrear portion93 of thepiston54. The rearrigid portion93 of thepiston54 is molded of a harder stronger plastic material and has a rearward facingcircular surface95 having a rearward extendingcoupling96 integrally formed thereon at its center. Thecoupling96 includes a rearwardly extendingcylindrical shaft97 on theaxis41 of thesyringe32 and a larger symmetricalcylindrical button98 integrally formed at the rear end of thecylindrical shaft97.
• Referring toFIG. 10, apiston drive assembly100 is illustrated contained within thehousing21. Thedrive assembly100 includes anelectric motor101 mounted within the fixedhousing21 and having arotary output shaft102 with adrive gear103 fixed to the remote end thereof. Thedrive gear103 is positioned for driving engagement with a drivengear104 fixed near the rear end of a drive screw orshaft105 supported at its rear end in abearing106 fixed in thehousing21. The screw orshaft105 has a continuous externalhelical thread107 thereon which mates with interior threads of acarriage108. Thecarriage108 is slidably supported in abushing109 fixed in thehousing21. Theshaft105 rotates within thehousing21 about alongitudinal axis112.
• At the forward end of thecarriage108 is supported a pair of hookedjaws114 which are pivotally mounted at their rearward ends by a pair of pivot pins115 to thecarriage108. Thejaws114 are biased toward theaxis112 by a pair ofballs116aand116bof resilient material positioned between the outside of thejaws114 and an innercylindrical wall117 of arecess118 formed in the forward end of thecarriage108. Theballs116a,116bare partially captured in depressions in the outer surfaces of thejaws114. Theballs116a,116bbias the jaws toward their innermost position toward theaxis112. The innermost position of the jaws is determined by aspacing block119 on theaxis112 of thecarriage108 at the center of thecavity118.
• When asyringe32 is locked in thejacket31 with itsaxis41 and the axis40 of thejacket31 may be in alignment with theaxis112 of theshaft105, theplunger54 may be located in thecylindrical body55 of thesyringe case50 in a position forward of theremote end56. Preferably, however, thejaws114 are displaced to the side ofaxis112 of theshaft105 so that as thejaws114 andcoupling tip98 are in their disengagement position, maximum clearance is provided so that thesyringe32 may be inserted into thejacket31 without the sterile internal walls of thesyringe31 touching the components of the drive, as illustrated in the figures.
• In the engaging position, thejaws114 are nonetheless in alignment with thecoupling98 on theaxes40 and41 of thejacket32 andsyringe32. In such a situation, thejaws114 may be in a retracted position at the center of theopening39 of thedoor25 adjacent to theproximate end34 of thejacket31, and out of engagement with thecoupling96 on theplunger54. From this position, operation of themotor101 rotates theshaft105 and drives thecarriage108 forwardly to move thejaws114 toward and into engagement with thecoupling96 on theplunger54. This engagement takes place as shown inFIG. 11 where a pair of tapered cam surfaces120 at the forward interface of the tips of thejaws114 engage the enlarged portion orbutton98 of thecoupling96 to expand the jaws, as shown inFIG. 11, to snap around thebutton98 of thecoupling96 to form a driving engagement between thedrive assembly100 and thecoupling96 of theplunger54 as shown inFIG. 12. Once so engaged, any forward or reverse movement of thecarriage108 under the power of themotor101 will cause theplunger54 to be driven either forwardly or backwardly in thesyringe body55.
• Disengagement of thejaws114 from thecoupling96 can thereafter be achieved by translational movement between thecoupling96 and thejaws114 between a disengaged position as shown inFIG. 4 and an engaged position as shown inFIG. 5. When theplunger coupling96 and thejaws114 are disengaged, thesyringe32 can be replaced without the need to retract thecarriage108 of thedrive100. This allows for rapid replacement of thesyringe32. Preferably, thejaws114 are either fully retracted toward thehousing21 where engagement by translation of thecoupling96 will occur, or thejaws114 are sufficiently within the jacket prior to replacement of the syringe so that thecoupling96 of thereplacement syringe32 will not contact thejaws114 except as thedrive100 is advanced.
• If sterility is not a problem, the most time saving approach would be to insert thesyringe32 into thejacket31 with its plunger all the way forward and the drive fully advanced so that, when the syringe is translated toward thejaws114, engagement will immediately occur and the plunger can be immediately retracted to fill the syringe.
• When asyringe32 is inserted into thejacket31 when theplunger54 is at its rearmost position toward theproximate end56 of thesyringe body55, thecoupling96 is in a position adjacent theproximate end56 of thesyringe body55 and projecting rearwardly therebeyond. When in such a position, engagement between thejaws114 and thecoupling96 is brought about by translational movement between the position shown inFIG. 4 and that shown inFIG. 5. In the unlocked or disengaged position shown inFIG. 4, theaxes40 and41 of thejacket31 and thesyringe32, respectively, as well as the center of theopening39 of thedoor25, lie spaced from and parallel to theaxis112 of theshaft105 as shown inFIG. 4. In the locked or engaged position, theaxis112 of theshaft105 is slightly eccentric relative to theaxes40 and41 of thejacket31 andsyringe32, respectively, as shown inFIG. 5. This translational movement, the engagement and disengagement between thecoupling96 and thejaws114 and the 45° rotational movement which secures thecap51 to thepressure jacket31 by engagement of thethreads85 and86 are brought about by operation of a translating andlocking mechanism125, which is best understood by reference toFIGS. 2-9.
• The translating andlocking mechanism125 includes a cam and lockingring127 which is rotatably retained in acircular recess126 in the back of thedoor25. Thering127 has a generallysemi-circular groove130 in the back surface thereof for receiving a springwire retaining clip131 having a pair of looped ends133 which extend through a pair ofslots134 in the rim of thering127 and into a selected one of three pair of diametricallyopposed notches135,136 and137 in the inner wall of the rim of therecess126 in thedoor25. The three pair ofnotches135,136 and137 represent three positions of the translating andlocking mechanism125 which are the locked, unlocked and release positions, respectively. The locked position of themechanism125 in which theloops133 of thering131 are in thenotches135, is that illustrated inFIGS. 5-7 and10. The unlocked position, in which theloops133 of thering131 are in thenotches136, is that illustrated inFIGS. 2-4 and8. The release position, in which theloops135 of theclip133 are innotches137, is that illustrated inFIG. 9. Thering127 is moved among these three positions by a manuallyaccessible handle138 in the form of acylindrical knob139 rotatably attached to alever arm140 formed integrally and extending radially from thering127 through aslot141 in the door25 (FIG. 1). Thering127 is retained in therecess126 by a pair ofscrews143 which thread into countersunkholes144 at the periphery of therecess126 in the back of thedoor25. Thesescrews143 have enlargedheads146, which, when seated in theholes144, overlie the edge of thering127, thereby securing it for rotatable movement within therecess126.
• As shown inFIGS. 2 and 6, thering127 has aninner periphery149 which is larger than the circumference of thebody55 of thesyringe case50. Accordingly, when thesyringe32 is inserted in thejacket31, theproximate end56 of thesyringe case50 extends through and is surrounded by theinner periphery149 of thering127. Asymmetric keyway structure, preferably in the form of three slots ornotches151,152 and153 (FIG. 6) are provided in the edge of theproximate end56 of thebody55 of thesyringe case50. The spacings between adjacent pairs of the notches151-153 differ from each other. Formed integrally of thering127 and projecting inwardly from theinner periphery149 thereof are three tabs orkeys155,156 and157. These tabs155-157 are spaced so as to fit into the respective notches151-153 in theproximate end56 of thebody55 of thesyringe case50 so as to rotate thesyringe32 as themechanism125 is rotated through actuation of thehandle138. Because the notches151-153 and the tabs155-157 are unequally spaced, they can only engage each other when thesyringe32 is inserted into thejacket31 in one and only one orientation. That orientation is one which will cause theslot62 of the collar52 (FIG. 3) to align 45° counterclockwise of the vertical when themechanism125 is in its unlocked position, which is a position in which it will be when the syringe is first inserted into thejacket31, and to be in an upwardly facing orientation, when fully loosened, when themechanism125 is moved to its locked position. Accordingly, thenotches135 and136 in therecess126, which receive theloops133 of thespring clip131 when respectively in the locked and unlocked positions, are 45° apart.
• The rotation of themechanism125 from the unlocked position to the locked position rotates thesyringe32 in thejacket31 and rotates the cap such that its threads move from an unlocked position as shown inFIG. 4 to the locked position ofFIG. 5, to secure the cap to thejacket31 by the engagement and tightening of thethreads85 and86.
• The translational movement of theaxes40 and41 with respect to theaxis112 is achieved by a fixed cylindrical cam follower or pin150 which projects outwardly from the fixed housing portion22 behind thering127 and into acam slot154 formed therein. Theslot154 is shaped so that theaxes40 and41 which remain fixed with respect to thering127, along with thedoor25, thejacket31, thesyringe32 and all of the structure mutually carried thereby, are moved in relation to theaxis112 of theshaft105 and the other structure mutually carried by the housing22, as themechanism125 is rotated. These axes move toward and away from each other in accordance with the shape of theslot154 determined by the radial distance from the point along theslot154 where it engages thepin150 to theaxes40 and41.
• Thecam slot154 in thering127 is shaped such that, when themechanism125 is in the locked position as shown, for example, inFIGS. 6 and 7, the distance between thepin150 and theaxes40 and41 is at a minimum and theaxis112 coincides with theaxes40 and41. This is illustrated inFIGS. 5 and 7 wherein thecoupling96 is shown positioned between thejaws114 and in mutual engagement therewith. When themechanism125 is in the unlocked position, with theloops133 ofclip131 in the notches135 (FIG. 6) of therecess126, thepin150 lies in theslot154 in the position shown inFIG. 8, which is farther displaced from theaxes40 and41 than in the position ofFIGS. 6 and 7, so that thecoupling96 is translated to a position outside of the center line of thejaws114, as shown inFIG. 8 and further illustrated inFIG. 4.
• In the release position, as shown inFIG. 9, thepin150 is positioned at theopen end160 of the cam surface of theslot154 so that thedoor25 can be rotated upwardly about thehinge pin26, as shown inFIG. 9, to open the space behind thedoor25 for access thereto. This position may be used for cleaning the area behind thedoor25 which is sometimes necessary because of possible leakage of fluid from thecavity61 into the space behind theplunger54. This can possibly occur because the fluid within thecavity61, when being injected by forward advancement of theplunger54, may be of relatively high pressure in the range, usually over 200 psi. For applications such as the injection of contrasting fluid for CT scanning, pressure may typically be in the range of from 25 to 300 psi., while in some angiographic injection applications the pressure may range to 1200 psi or higher.
• In addition, leakage rearwardly along the exterior of theneck59 of thesyringe32 can cause fluid to flow between thebody portion55 of thesyringe32 and thejacket31. For this reason, thecap51 is caused to fit snugly against the forward surface of theconical portion57 of thesyringe32 at least sufficiently to restrict the flow of this leaking fluid onto theneck59. This is assisted by the configuration of thecap51 at therim87 thereof so as to divert away from the space between thesyringe32 andjacket31 fluid which might leak from the nozzle.
• The front of thehousing21 has formed thereon adoor stop185 having aslot186 formed therein for receiving a lug187 of thedoor25, to restrain thedoor25 against forward force exerted by thedrive100. Behind the front of thehousing21 adjacent thestop185 is amagnetic sensor188, which is responsive to the presence of amagnet189 in thelever arm139 of thehandle138. Thesensor188 generates a signal to thecontrol module16 to activate thedrive100 only when themechanism125 is in its locked position.
• Referring toFIG. 13, there is illustrated alocking mechanism225 that is an alternative to thelocking mechanism125 described above. In thelocking mechanism225, a stationary gearedrack250 is provided fixed to thehousing21. A mating gear segment254 is formed on the outer rim of thealternative locking ring227 of this embodiment. The gear segment254 andrack250 replace and function in the same way as theslot154 and pin150 of the embodiment described above. As themechanism225 is rotated by thehandle138, thedoor25 that carries thejacket31 and thesyringe32 is translated to bring thecoupling96 into or out of engagement with thejaws114 of thedrive100. Simultaneous with this translatory motion, thesyringe32 is rotated in thejacket31 to lock or unlock thesyringe32 to thejacket31 by engagement or disengagement of thethreads86 on thesyringe32 with thethreads85 on thejacket32.
• FIG. 14 illustrates an alternative to the embodiment of thecoupling96 described above. In the embodiment ofFIG. 14, there is provided acoupling296 that is T-shaped, having arectangular endpiece298 at the rearward end of a cylindrical or square shaft297 on the rearwardly facingcircular surface95 of theplunger54. Such acoupling296 engages thejaws114 by rotation of thelocking mechanism125 or225, preferably through an angle of 90°. When the orientation of theendpiece298 is parallel to the plane of thejaws114, thedrive100 is locked to theplunger54 so that axial movement of thedrive100 moves the plunger axially, in the forward direction to expel fluid form thesyringe cavity61, or in a rearward direction to fill thecavity61 with fluid. When theendpiece298 is perpendicular to the plane of thejaws114, thecoupling296 will move into or out of engagement with thejaws114 upon relative axial movement between theplunger54 and thedrive100. Thus, with this embodiment, rotational motion, rather than translational motion, causes engagement and disengagement of thecoupling296 by thejaws114. With this embodiment, orientation of thesyringe32, when loaded into thejacket31, is preferably maintained through the cooperation of the notches151-153 and the tabs154-156 (FIG. 4), so that thecoupling296 will enter thejaws114, when thesyringe32 is inserted into thejacket31, with theendpiece298 perpendicular to the pair ofjaws114.
• The locking structure between thesyringe32 and thepressure jacket31 should provide for retention of thesyringe32 in thejacket31 against the force of the fluid pressure in thecavity61 or axial force otherwise exerted on theplunger54 by thedrive100. This locking of thesyringe32 to thejacket31 is preferably achieved, as shown inFIG. 5, by structure at or near theforward wall57 of thesyringe case50. In accordance with the embodiment ofFIG. 15, such structure may includeexternal threads200 on the forward end of thesyringe body257, which mate withinternal threads201 at the remote end of thejacket31. With such an embodiment, thesyringe32 is preferably provided with anannular flange203 around thebody257 at the juncture of thebody257 with thesyringe front wall258. Theflange203 inhibits the flow of leaked fluid into the space between thesyringe body257 and thejacket31. With such an embodiment, thewall258 is either thickened, provided with reinforcing such as theribs208, or provided with other structure to resist deformation of thewall258 under the pressure of the fluid within thecavity61.
• Alternatively, areusable split clip210 may be employed to secure acontinuous flange203 of such a syringe to acontinuous flange212 at the end of the pressure jacket in the embodiment ofFIG. 16. As a further alternative as shown inFIG. 17, aring clip210ahaving anouter rim215 and rotatably mounted to thesyringe31, encircles and engages outwardly projecting threads of adisk flange213 formed at the front end of thejacket31, as thesyringe32 is twisted onto thejacket31, to engage the jacket in a manner similar to thethreads85 and86 in the embodiment ofFIGS. 2-12 above.
• The invention has been described in the context of its preferred embodiments. It will be appreciated by those skilled in the art that variations and alternatives to the embodiments described may be employed without departing from the principles of the present invention. Accordingly, this patent is not intended to be limited except by the scope of the following claims:

Claims (22)

1. A disposable replacement syringe for a front loadable injector for injecting liquid into an animal, where the injector has a syringe receiving opening on the front thereof and has syringe mating structure circumferentially displaced inside the opening, the disposable syringe comprising:

a hollow body having a cylindrical tubular wall, a central longitudinal axis, a closed forward end having a discharge outlet therein, and an open rearward end;

a plunger snugly slidable within the hollow body in direct contact with the inside of the tubular wall and having a rearwardly facing drive engaging coupling thereon;

an annular flange extending outwardly from the hollow body and monolithic therewith, the annular flange lying in a plane perpendicular to the longitudinal axis of the body; and

locking structure spaced longitudinally a fixed distance rearwardly from the annular flange monolithic with and extending radially from the tubular wall of the body a distance smaller than the outward extension of said annular flange, the locking structure being configured to engage the mating structure internal to the opening on the front of the injector to lock the syringe thereto and to thereby urge the annular flange against the opening.

2. The disposable replacement syringe ofclaim 1 for use with an injector having a pressure jacket extending forwardly therefrom, the jacket having a cylindrical bore therein, the opening of the injector being the hollow bore of the jacket, and wherein the mating structure is a plurality of internal sections fixedly located on the inside of the jacket, wherein:

the syringe locking structure comprises radially extending mating sections positioned in a plane perpendicular to the axis of the body of the syringe so as to align with internal sections on the jacket when the syringe is inserted in the jacket and to lock the syringe to the jacket.

3. The disposable replacement syringe ofclaim 2, wherein:

the annular flange is in the form of a continuous annular ring surrounding the body; and

the locking structure forms means for sealably urging the annular flange against the jacket when the syringe is locked to the jacket to inhibit leakage of spilled fluid into the injector.

4. The disposable replacement syringe ofclaim 1, wherein:

the annular flange extends outwardly from the forward end of the hollow body.

5. The disposable replacement syringe ofclaim 1, wherein:

the locking structure extends radially outwardly from the tubular wall adjacent the forward end of the hollow body.

6. The disposable replacement syringe ofclaim 1, wherein:

the locking structure comprises a four equally spaced sections lockable to internal sections of the mating structure on the injector upon rotation of 45 degrees about the axis.

7. The disposable replacement syringe ofclaim 1, wherein:

the locking structure comprises four equally spaced sections each spanning not more than 45 degrees about the axis.

8. The syringe ofclaim 1, for use with an injector having a tubular member extending forwardly from the front thereof and having a cylindrical bore therein forming the opening at the front of the injector, the tubular member having a circular front end lying in a plane; and further comprising:

means, including the locking structure, for urging the annular flange rearwardly against the front end of the tubular member.

9. The syringe ofclaim 1 for use with an injector having a continuous rim surrounding and forming the periphery of the opening, and wherein:

the annular flange is in the form of a continuous annular ring; and

the locking structure urges the annular flange rearwardly against the syringe receiving opening when the syringe is locked to the injector to form a seal with the opening to inhibit leakage of spilled fluid into the injector.

10. The disposable replacement syringe ofclaim 1, wherein:

the locking structure includes a plurality of radially extending mating sections.

11. A front loadable power injector for injecting liquid into an animal comprising:

an injector having a housing, a syringe receiving opening and a plunger driving ram mounted in the housing and extendable along an axis through the opening;

a syringe having a hollow body having a cylindrical tubular wall, a central longitudinal axis, a closed forward end having a discharge outlet therein, an open rearward end, a plunger snugly slidable within the hollow body in direct contact with the inside of the tubular wall and having a rearwardly facing drive engaging coupling thereon, an annular flange monolithic therewith extending around and outwardly from the hollow body and perpendicular to the longitudinal axis of the body, and locking structure monolithic therewith spaced longitudinally rearwardly from the annular flange and extending radially from the tubular wall of the body a distance smaller than the outward extension of said annular flange;

the locking structure being sized to engage the injector at the opening so as to lock the syringe to the injector to thereby urge the annular flange against the opening.

12. The injector ofclaim 11 wherein:

the injector has a pressure jacket extending forwardly from the housing, the jacket having a cylindrical bore therein, the syringe receiving opening of the injector being in the bore of the jacket; and

the syringe is locked to the opening of the jacket.

13. The injector ofclaim 12 further comprising:

means including the locking structure for sealably urging the annular flange against the jacket.

14. The injector ofclaim 12 wherein:

the jacket has a circular front end lying in a plane; and

the annular flange is sealably urged rearwardly against the front end of the jacket.

15. The injectorclaim 11 wherein:

the annular flange is in the form of a continuous annular ring lying in a plane and surrounding the hollow body; and

the ring is configured such that, when urged against the opening, a seal is formed to inhibit leakage of spilled fluid into the injector.

16. The injectorclaim 11 wherein:

the annular flange extends outwardly from the forward end of the hollow body; and

the injector includes a cylindrical member extending forwardly from the injector housing and having a hollow bore therethrough, the syringe receiving opening being at an end of the bore remote from the injector housing.

17. The injector ofclaim 11 wherein:

the locking structure extends radially outwardly from the tubular wall adjacent the forward end of the hollow body of the syringe.

18. The injector ofclaim 11 wherein:

the locking structure and mating structure for engagement therewith at the opening each include four equally spaced thread sections; and

the sections are configured to mutually engage upon rotation of the syringe of 45 degrees.

19. The injector ofclaim 18 wherein:

the locking structure and mating structure for engagement therewith at the opening each include four equally spaced thread sections spanning not more than 45 degrees.

20. The injector ofclaim 11 wherein:

the injector housing has a tubular member extending forwardly from the front thereof and having a cylindrical bore therein forming the syringe receiving opening;

the tubular member has a circular front end lying in a plane; and

the annular flange is sealably urged rearwardly against the front end of the tubular member.

21. The injector ofclaim 11 wherein:

the locking structure and the mating structure therefor at the opening each include equally spaced thread sections; and

the sections are configured to mutually engage upon rotation of the syringe of 45 degrees.

22. The injector ofclaim 11 wherein:

the locking structure and the mating structure therefor at the opening each include equally spaced thread sections spanning not more than 45 degrees.

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