Auto-injector for retractable prefilled syringe
An actuation mechanism for an automatic injector includes a first actuation spring, a first actuation pill, a second actuation spring, and a second actuation pill. In an initial configuration the first actuation spring resides in a compressed, energized state substantially within an upper portion of first actuation pill and the second actuation spring resides in a compressed, energized state between the first actuation pill and the second actuation pill. An automatic injector includes a housing, an activation mechanism, an actuation mechanism, and a syringe cartridge having a plunger and a needle assembly. A retractable syringe may be utilized as a syringe cartridge, such as a prefilled retractable syringe with integrated safety features which retract the needle after use. The automatic injector may be utilized to inject the needle, deliver a drug treatment, and activate retraction of the needle. Methods of assembly and operation are also provided.
1. An actuation mechanism for an automatic injector, comprising: a first actuation spring, a first actuation pill, a second actuation spring arranged distal to and coaxially with the first actuation spring and a second actuation pill, wherein in an initial configuration the first actuation spring resides in a compressed, energized state substantially within an upper portion of the first actuation pill, and the second actuation spring resides in a compressed, energized state between the first actuation pill and the second actuation pill, and the first actuation pill and the second actuation pill are detachably, directly connected to prevent relative movement between the first actuation pill and the second actuation pill and to maintain the second actuation spring in the compressed, energized state between the first actuation pill and the second actuation pill.
2. The actuation mechanism of claim 1 , wherein the first actuation pill and the second actuation pill are detachably, directly connected by engagement between one or more connector prongs of the first actuation pill and one or more respective connection bridges of the second actuation pill.
3. The actuation mechanism of claim 2 , wherein the one or more connector prongs of the first actuation pill each have protrusions which extend outwards from the first actuation pill.
4. The actuation mechanism of claim 1 , wherein the first actuation pill has one or more locking hooks at a proximal end of the first actuation pill.
5. The actuation mechanism of claim 1 , wherein the second actuation pill has one or more retention prongs at a distal end of the second actuation pill.
6. The actuation mechanism of claim 1 , wherein the first actuation pill has one or more guide prongs extending outwards from the first actuation pill.
7. The actuation mechanism of claim 1 , wherein the first actuation pill and second actuation pill are substantially cylindrical.
8. An automatic injector comprising a housing, an activation mechanism, an actuation mechanism, and a syringe cartridge having a plunger and a needle assembly, wherein the actuation mechanism comprises: a first actuation spring, a first actuation pill, a second actuation spring arranged distal to and coaxially with the first actuation spring and a second actuation pill, wherein in an initial configuration the first actuation spring resides in a compressed, energized state substantially within an upper portion of the first actuation pill, and the second actuation spring resides in a compressed, energized state between the first actuation pill and the second actuation pill, and the first actuation pill and the second actuation pill are detachably, directly connected to prevent relative movement between the first actuation pill and the second actuation pill and to maintain the second actuation spring in the compressed, energized state between the first actuation pill and the second actuation pill.
9. The automatic injector of claim 8 , wherein the housing comprises an upper housing and a lower housing, and wherein the upper housing, the lower housing, the first actuation pill, and the second actuation pill are substantially cylindrical.
10. The automatic injector of claim 8 , wherein the first actuation pill has one or more locking hooks at a proximal end of the first actuation pill which initially engage a locking plateau at an interior proximal end of the housing.
11. The automatic injector of claim 10 , wherein the activation mechanism is capable of engaging the one or more locking hooks of the first actuation pill to disengage the locking hooks from the locking plateau of the housing.
12. The automatic injector of claim 8 , wherein the first actuation pill and the second actuation pill reside within the housing and are detachably, directly connected with each other by engagement between one or more connector prongs of the first actuation pill and one or more respective connection bridges of the second actuation pill.
13. The automatic injector of claim 12 , wherein the one or more connector prongs each have protrusions which interface with longitudinal channels along an inner surface of the housing.
14. An automatic injector comprising
a housing having an inner surface, and including longitudinal channels and one or more recesses along the inner surface,
a syringe cartridge having a plunger and a needle assembly,
an activation mechanism, and
an actuation mechanism, the actuation mechanism including
a first actuation pill residing in the housing and including one or more connector prongs, the one or more connector prongs each having protrusions which interface with the longitudinal channels along the inner surface of the housing,
a first actuation spring, the first actuation spring residing, in an initial configuration, in a compressed, energized state substantially within an upper portion of the first actuation pill,
a second actuation spring, the second actuation spring residing, in the intial configuration, in a compressed, energized state between the first actuation pill and the second actuation pill, and
a second actuation pill residing in the housing and including one or more connection bridges,
wherein, in the initial configuration, the first actuation pill and the second actuation pill are detachably, directly connected to prevent relative movement between the first actuation pill and the second actuation pill and to maintain the second actuation spring in the compressed, energized state between the first actuation pill and the second actuation pill, the first actuation pill and the second actuation pill being detachably, directly connected with each other by engagement between the one or more connector prongs of the first actuation pill and the respective one or more connection bridges of the second actuation pill,
the protrusions of the connector prongs being adapted to interface with and expand into the recesses of the housing to permit the one or more connector prongs of the first actuation pill to disengage from the respective one or more connection bridges of the second actuation pill.