WO1992014434A1

WO1992014434A1 - Syringe tip connection apparatus with insertion indicator

Info

Publication number: WO1992014434A1
Application number: PCT/US1992/001470
Authority: WO
Inventors: George K. Austin, Jr.; Mathew H. Parlier
Original assignee: A-Dec, Inc.
Priority date: 1991-02-22
Filing date: 1992-02-24
Publication date: 1992-09-03
Also published as: AU1425592A

Abstract

A syringe tip connection apparatus (110) includes an internal detent mechanism (160) for securing the connection between a syringe tip (20) and the syringe head (22). The syringe tip (20) is provided with an indicium (80) for providing a visual indication to the user that the syringe tip (20) is properly connected to the syringe head (22).

Description

SYRINGE TIP CONNECTION APPARATUS WITH INSERTION INDICATOR

_* TECHNICAL FIELD

The present invention relates to an apparatus fo , 5 connecting a syringe tip to a syringe head.

BACKGROUND INFORMATION A syringe is used in dentistry for controlled delivery of liquid or air, or a combination of liquid and air to the mouth of the patient. A syringe generally 10 includes a syringe head that is manipulated by the operator and connected via flexible conduits to a source of water and compressed air. A tubular elongated syringe tip is connected to the syringe head.

A conventional syringe tip comprises an inner 15 tube and a concentric outer tube. The inner tube mates a one end with a liquid-outlet port in the syringe head, thereby providing a conduit for the liquid from the syringe head to the free end of the syringe tip.

The outer tube of the syringe tip has an inside 20 diameter that is slightly greater than the outside diameter of the inner tube, thereby defining between the inner and outer tubes an annular air delivery chamber extending along the length of the syringe tip. The air delivery chamber is substantially closed at the tip end 25 that connects to the syringe head, except for an air- inlet port in the outer tube that connects that chamber with an air-outlet port carried in the syringe head. Air flows out of the air delivery chamber at the free end of the syringe tip. 30 The operator controls the flow of liquid or gas through the syringe tip by operating valves that are mounted in the syringe head.

Syringe tips are disinfected after use with a single patient. Consequently, the mechanism employed for 35 connecting the syringe tips to a syringe head should provide for quick and reliable replacement of syringe tips, while ensuring that the syringe tip is properly reconnected each time it is replaced. SUMMARY OF INVENTION This invention is directed to a syringe tip connection apparatus that permits the rapid removal and replacement of syringe tips without the use of tools and provides a useful indication to the user of whether the syringe tip is properly reconnected to the syringe head. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an exploded perspective view depicting a syringe tip connection apparatus formed in accordance with the present invention.

Fig. 2 is an enlarged cross sectional view of the apparatus connected to a syringe head.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to Figs. 1 and 2, the syringe tip connection apparatus includes a connector assembly 110 and syringe tip 20, which components combine to permit connection and disconnection of the syringe tip 20 to a conventional syringe head 22 without the use of tools. The conventional syringe head 22 includes a threaded aperture 24, the innermost end of which aperture is in a fluid communication with a liquid-outlet port 26 and an air-outlet port 28 formed in the head 22. The liquid-outlet port 26 is connected to a flexible conduit (not shown) that extends from the syringe head 22 to a source of liquid, such as water. Similarly, the air- outlet port 28 is connected to a flexible conduit that connects the syringe head 22 with a source of compressed air. The liquid-outlet port 26 and the air-outlet port 28 are opened and closed by internal valves. A (mult)- position button 30 is manipulated by the operator to control the valves.

The syringe tip 20 includes an elongated inner tube 32 and a concentric outer tube 34. The syringe tip 20 has a connecting end 36 that connects to the syringe head 22, and a free end 38 from which the liquid and air are expelled.

The syringe tip 20 connection to the syringe head 22 is effected by the connector assembly 110. The connector assembly 110 includes a generally tubular coupler 140. The coupler 140 has near its innermost end 142 (Fig. 2) a threaded portion 144 that threads into th threaded aperture 24 in the syringe head 22. The interi surface 176 of the coupler 140 is shaped to engage an

Allen wrench that can be extended into the coupler 140 f threading the coupler 140 into the head 22 before the syringe tip 20 is inserted through the central opening 1 in the connector assembly. An annulus 146 is formed to protrude from the innermost end 142 of the coupler 140. An O-ring 148 fit inside the annulus 146. The annulus 146 and O-ring 148 are sized so that the O-ring 148 is firmly compressed against the syringe head 22 and, once the syringe tip 20 is connected to the syringe head 22, around the portion o the syringe tip inner tube 32 that protrudes from the outer tube 34 (Fig. 2). The O-ring 148, therefore, seals the connection between the liquid-outlet port 26 and the inner tube 32. The outer tube 34 of the tip 20 is crimped to th inner tube 32 at connecting end 36 to close the end of an air delivery chamber 70 that is defined between the outer tube 34 and the inner tube 32. An annular recess 72 is formed near the crimped end. Two or more inlet ports 74 are formed through the outer tube 34 at the recess 72. A air passage 75 is defined between the outer surface of th tube 34 and the inner wall 176 of the coupler 140 at the crimped end of the outer tube 34. With the syringe tip 2 connected to the head 22, the air passage 75 is in fluid communication with the air-outlet port 28 in the syringe head 22 via holes 178 in the innermost end 142 of the coupler 140.

The outer end 166 of the coupler 140 that is opposite the annulus 146 carries external threads 150 for receiving a retainer nut 152 through which nut the syring tip 20 extends as described below. A smooth portion of the exterior wall of the coupler 140 between the threaded portions 144, 150 carries an O-ring 154 for sealing the annular space between the retainer nut 152 and syringe head 22 (Fig. 2) .

The outer end 166 of the coupler 140 has an annular recess 163 formed therein for carrying a keeper O ring 161. The keeper O-ring 161 and recess 163 are sized so that the ring 161 is continuously compressed against the syringe tip 20 that is inserted into the syringe head 22. The keeper O-ring 161 also serves to improve the sea between the syringe tip outer tube 34 and the interior surface 176 of the coupler 140 so that air in the passage 75 will be directed through the holes 178 in coupler 140 and into the air delivery chamber 70 of the syringe tip.

The retainer nut 152 is a hollow, generally frustum shaped member having an inner end 156 and an outer end 158. The interior of the inner end 156 of the retainer nut 152 is threaded to engage the threads 150 on the coupler 140. Part of the outer surface of the inner end 156 is hexagonal in cross-section for receiving a wrench for adjusting the assembly 110 as described below. The retainer nut 152 is movable relative to the coupler 140 between a locked position (solid lines in Fig. 2) and an unlocked position (shown in dashed lines in Fig. 2) as the nut 152 is threaded by hand toward or away from the syringe head 22. In the locked position, the retainer nut 152 is advanced on the threads 150 of the coupler in a manner such that the tapered interior surface 168 of the retainer nut 152 bears upon a split collet 164 that surrounds the syringe tip 20. The collet 164 is forced by the retainer nut 152 toward the outer end 166 of the coupler 140. As a result, a flanged end 165 of the split collet 164 bears upon a resilient detent O-ring 160 that is located between the collet flanged end 165 and the keeper O-ring 161 and that fits within the annular recess 62 in a syringe tip 20 whenever the syringe tip is inserted through the central opening 175 of the assembly 110 and into the syringe head 22. It will be appreciated that the central opening 175 is defined by the interior surfaces of the coupler 140, collet 164, and outer end of the retainer nut 152.

The force of the collet 164 against the detent O ring 160 and against the adjacent keeper O-ring 161 compresses those rings 160, 161 against the outer surface of the syringe tip 20. The surface 168 of the retainer nut 152 wedges the collet 164 against the syringe tip 20 for restricting rotation of the syringe tip about its longitudinal axis. Moreover, as the movement of the spli collet 164 along the tip 20 is resisted by the compressed rings 160, 161, the outermost end 167 of the collet 164 i squeezed against the syringe tip 20 by the retainer nut 152 as the nut 152 is moved toward the locked position. The collet 164, therefore, increases the rotational resistance applied to the syringe tip 20. Hand-tightenin of the retainer nut 152 provides sufficient force to the collet 164 so that the collet 164 prevents removal of the tip 20 from the head 22 unless the retainer nut 152 is thereafter loosened by hand. As the retainer nut 152 moves toward the locked position, an internal shoulder 169 formed in the nut 152 moves across part of the radially outer surface of the detent O-ring 160 to limit expansion of the detent O-ring 160 (as the O-ring 160 is compressed by the collet 164) away from the syringe tip, which expansion would otherwis reduce the force of the O-ring 160 against the tip 20.

As noted, the syringe tip 20 is held by the collet 164, detent O-ring 160, and keeper O-ring 161 against rotation whenever the connector assembly 110 is i the locked position. If desired, the retainer nut 152 ca be tightened into the locked position by applying a wrenc to the hexagonal surface portion of the outer surface of the retainer nut 152.

During manufacture of the assembly 110, a portio of the retainer nut threads 150 is deformed after the retainer nut 152 is threaded onto the coupler 140. As a result, the retainer nut 152 can not be threaded off the coupler 140 as the retainer nut is moved to the unlocked position. The effect of this irremovable attachment of the retainer nut 152 to the coupler 140 is to eliminate the possibility of losing the small internal parts (colle 164 and 0-rings 160, 161, 154) of the assembly 110, which loss could otherwise occur if the nut 152 could be completely removed from the coupler 140.

The unlocked position (dashed lines in Fig. 2) into which the connector assembly 110 may be adjusted not only permits rotation of the syringe tip 20 about its longitudinal axis, but also allows quick disconnection an reconnection of the tip 20 without the use of tools. In this regard, the retainer nut 152 is partly unthreaded from the coupler 140, thereby reducing the force applied by the collet 164 to both the detent O-ring 160 and to th syringe tip 22. Specifically, as the retainer nut 152 is moved to the unlocked position, the force of the tapered interior surface 168 of the retainer nut 152 against the outermost end 167 of the collet 164 is substantially eliminated, thereby relieving the force of the split collet 164 acting on the detent ring 160 and against the syringe tip 20.

Part of the detent O-ring 160 continuously extends into the assembly opening 175. That part of the resilient detent O-ring 160 remains urged against the syringe tip 20 that is inserted in the assembly 110. As a result, the ring 160 serves as a detent mechanism received in the recess 62 of the tip 20 for securing the tip to the assembly 110 even though the retainer nut 152 is loosened to the unlocked position. With the retainer nut 152 in the unlocked position, the syringe tip 20 can be quickly and easily removed and replaced by hand. To ensure that a replaced syringe tip is properly connected to the syringe head 22, an indicium 80 is placed on the syringe tip 20 near the connecting end 36 of the tip. The indicium 80 is located so that whenever the tip 20 is properly reconnected to the syringe head 22 (that is, whenever the detent O-ring 160 is received within the recess 62 of the tip) the indicium 80 will be adjacent to the outer end 158 of the retainer nut 152.

Preferably, the indicium 80 comprises a annular groove formed in the outer tube 34 of the syringe tip 20. The indicium 80 is located relative to the recess 62 so that the indicium will be obscured from the user's view just inside the outer end 158 of the retainer nut 152 whenever the tip is properly connected. Put another way, the user connects the syringe tip to the head by pushing the tip inwardly (to the right in Fig. 2) until the indicium 80 is no longer visible.

It can be appreciated that in the absence of an indicium, an otherwise smooth, continuous outer surface o the outer tube 34 would provide the user with no visual clue as to whether or not the syringe tip is properly connected to the syringe head 22.

Having illustrated and described the principles of the invention in a preferred embodiment, it should be apparent to those skilled in the art that the invention can be modified in arrangement and detail without departing from such principles. For example, there are numerous other methods for marking or forming structural features of the syringe tip to provide the indicium function described above. Moreover, the syringe tip of the present invention can be employed with any connector apparatus that includes an internal detent mechanism for securing the syringe tip in place. In view of the foregoing, we claim all modifications coming within the spirit and scope of the following claims.

Claims

CLAIMS 1. A syringe tip connection apparatus, comprising: a connector having an inner end attachable to a syringe head and an outer end, the connector having an opening therein; a detent member located within the connector, a part of the detent member being urged into the opening; a syringe tip having a first end shaped to fit inside the connector opening and having a recess formed therein for receiving the part of the detent member; and an indicium carried on the syringe tip and located so that the indicium is adjacent to the outer end of the connector whenever the part of the detent member is received in the syringe tip recess.

2. The tip of claim 1 wherein the indicium is a groove formed in the tip.

3. The tip of claim 1 wherein the indicium is obscured by the outer end of the connector whenever the part of the detent member is received in the syringe tip recess.

4. The tip of claim 3 wherein the indicium is a circumferential groove formed in the tip.

5. The tip of claim 1 wherein the detent member is a resilient ring mounted within the connector opening so that part of the ring protrudes into the opening.

6. A syringe tip, comprising an elongated tubular part having a first end connectable with a syringe head, the tubular part having a recess formed therein near the first end of the tubular part; and an indicium carried on the tubular part at a predetermined distance from the recess, the recess being located between the indicium and the first end of the syringe tip.

7. The tip of claim 7 wherein the indicium is a groove formed in the tip.

8. A method of making a syringe tip that is use with a connector that has an inner end attachable to a syringe head and an outer end, wherein the connector has an opening therein, and wherein a detent member is locate within the connector with a part of the detent member being urged into the opening, the method comprising the steps of: shaping a tubular member to fit into the opening in the connector; forming in the tubular member a recess for receiving the part of the detent member that is urged int the connector opening; and placing on the tubular member an indicium near the recess for providing an indication of whether the detent member part is received in the recess.

9. The method of claim 8 wherein the placing step includes the step of forming in the tubular member a groove for defining the indicium.

10. The method of claim 8 wherein the placing step includes the step of locating the indicium so that the indicium is adjacent to the outer end of the connecto whenever the part of the detent member is received in the recess.

11. The method of claim 10 wherein the placing step also includes the step of forming a circumferential groove in the tubular member.