Methods performed by medicine injection apparatuses
Operations performed by a medicine injector having a barrel with a receiving cavity to slidably receive a syringe subassembly for axial movement therein. Upon removal of a safety and release of a syringe driver, the syringe driver moves forward and injects the syringe needle. One or more penetration controls are shown for controlling injection needle penetration depth. In some forms of penetration control a sleeve and spring are used in the methods performed. This construction and a cushioning piece or pieces may be used to reduce the forces experienced by the syringe subassembly. A load distribution ring may further be used with a cushion, spring and guide ring which may be used to help distribute deceleration loading experienced by the syringe subassembly.
1. A method performed during operation of a medicine injection apparatus, comprising:
selecting a medicine injector having:
a tube including a barrel and a nose cap attached thereto;
a receiving cavity within the tube;
a syringe subassembly within the receiving cavity, the syringe subassembly including a reservoir, an injection needle, a hub between the reservoir and the injection needle, and a resilient cushion on the hub;
a driver adjacent one end within the tube; and
a penetration controller adjacent another end within the tube opposite the one end, the penetration controller including a control sleeve that is removable from the tube and a return spring within the control sleeve radially between the control sleeve and a part of the syringe subassembly; the control sleeve having an abutment surface at one end, another end opposite the one end, and an inside diameter; the return spring having an enlarged portion with an outside diameter greater than the inside diameter of the control sleeve; the enlarged portion of the return spring being retained between the other end of the control sleeve and the nose cap; and the resilient cushion being located axially between the abutment surface and at least a part of the hub;
driving the syringe subassembly toward extension of the injection needle from the barrel, the syringe subassembly contacting the abutment surface;
absorbing energy of the syringe subassembly and stopping the needle at a desired position using the control sleeve and the return spring; and
absorbing energy of the syringe subassembly in the resilient cushion.
2. A method according to claim 1 wherein the control sleeve has a length and the spring extends along substantially all of the length of the control sleeve, the spring exhibiting a fully compressed length and the fully compressed length of the spring being less than the length of the control sleeve.
3. A method according to claim 1 wherein the other end of the control sleeve comprises a plurality of flange lobes, the enlarged portion of the spring comprises at least one coil exhibiting the outside diameter, and the at least one coil is retained between the flange lobes and the nose cap.
4. A method according to claim 1 wherein the other end of the control sleeve comprises a plurality of flange lobes, which are in frictional engagement with the nose cap.
5. A method according to claim 1 wherein the resilient cushion is in the form of a ring around the hub.
6. A method according to claim 5 wherein the syringe subassembly further comprises a load distribution ring located axially between the cushion ring and the abutment surface and the absorbing energy in the resilient cushion further comprises the load distribution ring distributing force to the resilient cushion as applied by the syringe subassembly to the abutment surface.