HIGH PRESSURE SYRINGE The present invention is directed to syringes. The invention has particular utility for injecting viscous materials into a manifold, needle, catheter or the like; for example, the very viscous dye required to visualize coronary anatomy in diagnosis and treatment of arterial diseases, and will be described in connection with such utility, although other utilities are contemplated.

Currently available syringes require the exertion of a tremendous amount of hand pressure, often resulting in suboptimal injections and hand fatigue. Most syringes used for this purpose involve two loops on opposite sides of the syringe for the first and second fingers and a plunger which either fits in the palm of the hand or is operated by the thumb. Such syringes are marketed by NAMIC, MERIT, Statco, Fruend, the ACS division of Eli Lilly and other medical device manufacturers. Recently, cardiovascular innovations introduced a high pressure syringe illustrated in Fig. 1 in which a syringe 30 is mounted in a frame 32 comprising a base 34 and a pivotally mounted lever arm 36 which provides a mechanical advantage for operating the syringe 30.

Yet another high pressure syringe is shown in U. S. Patent 5,078,690.

Referring to Figs. 2 and 3 which are assembly drawings from U. S. Patent 5,078,690, the syringe comprises an outer housing portion generally indicated at 2, and an inner portion generally indicated at 4. The outer portion 2 preferably is formed of an optically transparent material, and has a downwardly extending finger grip handle 6 which is shown to be open at the rear 7. The inner housing has a downwardly extending inner handle 8 which fits within the opening 7. The upper part of the outer housing 2 defines an inner cylinder 10 in which a piston 12, carried by the inner housing 4 can fit.

Outer housing portion 2 and inner portion 4 each preferably comprise unitary molded parts formed of a medically approved material such as polycarbonate or polypropylene. A resiliently deformable sealing tip 14, formed of a

medical grade rubber, elastomer or the like, or an O-ring is carried on the forward end 24 of piston 12 and provides a high pressure seal between the piston 12 and the inner cylinder 10. A fluid feed opening 16 is provided in outer housing 2 to permit egress of the high pressure viscous liquid into a suitably attached catheter, manifold, needle or the like.

The catheter or other injection system device is attached with a female coupling known in the trade as a LUER-LOK to the outer housing male LUER-LOK tip 22. An alternative embodiment utilizes a captive and rotatable female threaded fitting with an O-ring seal affixed to the syringe tip 22. Both embodiments incorporate rotatable couplings that are snapped together.

The present invention provides an improvement in high pressure syringes. More particularly, in accordance with the present invention, there is provided a hand gun-like shape syringe having a barrel with a handle. A plunger is mounted within the barrel. A disc trigger is rotatably mounted on the handle, and has a plurality of teeth on a peripheral edge thereof for interfacing with gear teeth on a stem of the plunger. In a preferred embodiment, a gear wheel is interposed between the rotatably mounted disc trigger and the stem of the plunger for providing further enhanced mechanical advantage.

Other features and advantages of the present invention will be seen from the following detailed description, taken in conjunction with the accompanying drawings, wherein: Figs. 1-3 are side elevational views of prior art high pressure syringe devices; Figs. 4 and 5 are cross-sectional views of a syringe made in a first embodiment of the invention; and Fig. 6 is a side-elevational view; and Figs. 7-10 are cross-sectional views of two alternative embodiments of syringes made in accordance with the present invention.

Referring to Figs. 4 and 5, the syringe in accordance with a first embodiment of the present invention has three main components, a barrel 40 with a handle 42, a slidably mounted plunger 44, and a rotatably mounted disc trigger. In addition to these elements, the syringe also has other necessary or miscellaneous components, such as a seal 50 on the plunger and a disc trigger pivot pin 54. The barrel with handle is similar to other syringe designs such as U. S. Patent No. 5,078,690 that have a hand gun-like shape.

The plunger 44 is slidably mounted within the barrel 40, and has gear teeth 56 which interface with teeth 58 of the disc trigger 46. The disc trigger 46 rotates about pivot pin 54 at its center and is used to move the plunger 44.

The disc trigger and plunger work together like a rack-and-pinion gear works.

When the upper portion 60 of the disc trigger 46 of the disc trigger is squeezed, it causes the plunger to move backward in the barrel thus filling the syringe with fluid. (See Fig. 4). Conversely, when the lower portion 62 of the disc trigger is squeezed, it causes the plunger to move forward and thus injecting the fluid into the catheter system. (See Fig. 5).

An alternative embodiment of syringe in accordance with the present invention is shown in Fig. 6-8.

Referring to Figs. 6-8, the syringe includes a barrel 70 with a handle 72, a slibably mounted plunger 74, a rotatably mounted disc trigger 76 and gear wheel 78. In addition to these, the syringe also has other necessary or miscellaneous components, such as a seal 80 on the plunger and pivot pins 84, 85. As before, the barrel with handle is similar to other syringe designs such as U. S. Patent No. 5,078,690 that have a hand gun-like shape. The plunger 74 is slidably mounted in the barrel, and has gear teeth 86 which interface with teeth 88 of the gear wheel 78. The gear wheel 78 is rotatably mounted and positioned between the plunger 74 and disc trigger 76, and is contained within the handle 72. The disc trigger 76 turns about pivot pin 84 at its center and is used to rotate gear wheel 78 by interface of teeth 90 with teeth 88 of

gear wheel 78 which in turn moves the plunger 74. The disc trigger, gear wheel, and plunger all work together like a rack-and-pinion gear works.

When the lower portion 90 of the disc trigger 76 of the disc trigger is squeezed, it causes the plunger to move backward in the barrel thus filling the syringe with fluid. (See Fig. 7). Conversely, when the upper portion 92 of the disc trigger is squeezed, it causes the plunger to move forward in the barrel, thus injecting fluid in the barrel into the catheter system. (See Fig. 8).

A further alternative embodiment of syringe in accordance with the present invention is shown in Figs. 9 and 10.

Referring to Figs. 9 and 10, the syringe includes a barrel 100 with a handle 101, a slidably mounted plunger 102, a rotatably mounted double disc trigger 103 and gear wheel 104. In addition to these, the syringe also has other necessary or miscellaneous components, such as a seal 105 on the plunger and pivot pins 106,107. As before, the barrel handle is similar to other syringe designs such as U. S. Patent No. 5,078,690 that have a gun-like shape. The plunger 102 is slidably mounted in the barrel, and has gear teeth 108 which interface with teeth 109 of the gear wheel 104. The gear wheel 104 is rotatably mounted and positioned between the plunger 102 and double disc trigger 103, and is contained within handle 101. The double disc trigger 103 turns about pivot pin 106 at its center and is used to rotate gear wheel 104 by interface of teeth 110 with teeth 109 of gear wheel 104 which in turn moves the plunger 102. The double disc trigger, gear wheel, and plunger all work together like a rack-and-pinion gear works. When the lower portion 111 of the double disc trigger 103 is squeezed, it causes the plunger to move backward in the barrel thus filling the syringe with fluid. (Fig. 9).

Conversely, when the upper portion 112 of the double disc trigger is squeezed, it causes the plunger to move forward in the barrel, thus injecting fluid in the barrel into the catheter system (Fig. 10), i. e. similar to the embodiment shown in Figs. 6-8. In this latter embodiment, the double disc

trigger 103 provides additional mechanical advantage over that of the embodiment of Figs. 6-8. As force is applied to the outer disc edge 113 of the double disc trigger, it yields a higher force on the inner disc edge 114. The increase in force is a ratio of the diameters of the edges of the disc. Thus, if an operator can apply X-pounds of force to the outer disc edge, a force of greater than X-pounds will be applied to the inner disc edge and in-turn a force of greater than X-pounds will be applied to the plunger. Finger ring syringes can only produce X-pounds of force on the plunger.

The aforementioned syringes have a handle mounted to the barrel that has a gun-like appearance. It is conceived within the present invention that the shape of the handle and barrel could be different. It is possible that the handle and barrel can be aligned to each other as opposed to nearly perpendicular. In this alignment, it is still possible to have the rack-and- pinion gear mechanisms described above in order to control in-and-out movement of the plunger via rotation of the disc trigger. It is also possible to design the trigger in a manner that does not rotate, but still drives a disc with gear teeth and thus controls in-and-out movement of a plunger.

The syringe of the present invention comfortably fits in the hand and it uses the natural kinematics and grip strength of the hand. This strength is definitely optimized when filling the syringe. Finger ring syringe designs require spreading the thumb away from the forefinger and middle finger in order to fill the syringe. The design of the present syringe uses a squeezing (or grip) action to fill and empty the syringe. The syringe design also provides mechanical advantage because of the rack-and-pinion gear works, particularly the Figs. 6-10 embodiments.

The syringe design of the present invention also has other performance requirements that are expected of syringes for this type of application. They include, but are not limited to the following: Design that maximizes strength of hand.

disposa and provided sterile.

* Inexpensive-the barrel and handle may be molded as a one-piece unit.

Easy to use.

* Volume of syringe = 15 cc or greater.

Minimum pressure threshold of 20 atm without leakage.

* Force required to fill syringe or inject solution not to exceed force requirements of current available syringes * Lucent, translucent, or see-through components as needed to visualize solutions and/or a suitably marked graduated scale 92.

* Fast; able to fill or inject syringe fast when needed, for example, when priming the manifold, catheter, or tubing.

* Low tendency for air bubbles, no more than current available syringes.

* Comply with mandatory or voluntary performance standards.

* All materials meet biocompatibility requirements.