Safety Syringe

TC30^®

Detailed Description

The front end of the barrel is defined by a specialized ratchet device/system, appropriately named the retaining device (11). The retaining device(11) has multiple equally spaced fingers(111) and troughs(112). Each of the fingers(111) and troughs(112) is L-shaped. At the end of each trough(112), there is an offset taper to securely receive the corresponding bosses(32) on the needle coupler(3), thereby securing the needle coupler(3) to the retaining device(11) on the barrel(1) (See Figure 6).

The plunger(2) has a neck(21) to allow for secure fitting of the rubber seal(22). The end of the plunger(2) is designed with a conical head(23) projecting from the neck(21) and multiple spatially set inclined teeth(24) corresponding to the inner aspect of the needle coupler(3) (See Figure 6).

The needle coupler(3) has a conical front end(31) to receive the needle hub(4). At the base of the coupler(3) are multiple evenly spaced bosses(32) to correspond to the troughs(112) of the previously described barrel(1). There is an exit hole(33) at the conical end(31) and a receiving hole(34) at the base (See Figure 8). The receiving hole(34) is designed with multiple recesses(35) to correspond with the inclined teeth(24) on the plunger(2) and a shoulder(36) to correspond with the conical head(23) of the plunger(2). The needle coupler(3) is adapted to hold a needle hub(4) on its front conical end(31). An O-ring seal(37) is mounted on the needle coupler(3) to prevent barrel leaking (See Figure 6, 7&8).

The needle hub(4) comprises of a sleeve(41) and a metal cannula(42) (See Figure 6).

When the TC30^® is assembled, the needle coupler(3) is secured to the needle hub(4). And when the needle coupler(3) is inserted into the barrel(1), Each boss(32) on the needle coupler(3) can then be coupled with each trough(112) on the barrel retaining device(11). The L-shaped fingers(111) help clamp the needle coupler(3) to the barrel(1). A counter-clockwise rotation of the needle coupler(3) will secure the bosses(32) into the trough(112). With this arrangement, the needle coupler(3) is prevented from accidental movement or disengagement from the barrel(1). The worry that the needle coupler(3) may be pushed into the barrel(1) when the needle(42) is being introduced into the medical vial during withdrawal is avoided (See Figure 6). Once the medication is withdrawn into the syringe, the plunger(2) can then be pushed forward during injection. The rubber seal(22) found around the neck(21) of the plunger(2) disallow leakage and allows for proper injection (See Figure 9).

After the medication is emptied from the barrel(1), the user can further push the plunger(2) inward forcing the conical head(23) of the plunger(2) into the receiving hole(34) of the needle coupler(3) (See Figure 9, P24). This action allows the resilient push rod(25) to rest inside the receiving hole(34); allows the incline teeth(24) to engage with their corresponding recesses(35) on the needle coupler(3); and allows the conical head(23) of the plunger(2) to secure with the shoulder(36) of the needle coupler(3) (See Figure 10).

Thereafter, the user can rotate the plunger(2) clockwise 30 degrees to allow for the engagement between the incline teeth(24) and the recesses(35), and to simultaneously allow for the release of the needle coupler(3) from the barrel(1) retaining device(11) (See Figure 11). After release of the bosses(32) on the needle coupler(3) from the L-shaped fingers(111) in the retaining device(11) of the barrel(1) and after engagement of the conical head(23) of the plunger(2) to the shoulder(36) of the needle coupler(3), the needle coupler(3) and plunger(2) assembly can then be withdrawn into the empty barrel(1) (See Figure 12). When the needle coupler(3) together with the needle hub(4) are pulled back into the barrel(1), the resilient push rod(25) will press against the needle coupler(3) and hub(4) to angle the needle(42) inside the barrel(1) (See Figure 12).

If the user accidentally pushes the plunger's conical head(23) into the shoulder(36) of the needle coupler(3), the plunger(2) can still be disengaged from the needle coupler(3) as long as the user does not rotate the plunger 30 degrees clockwise.

Maintaining by Ching-Liu Studio