Needle assembly for drug pump

1. A needle assembly adapted for fluid communication with a vial containing a substance to be delivered to a subject, the needle assembly comprising:

a needle held in a needle holder, said needle holder confined to move in a housing; and

an activation mechanism for activating delivery of the substance through said needle, said activation mechanism comprising a safety latch having a down position that initially impedes movement of said needle holder, wherein when said safety latch is placed on the subject, said safety latch moves from said down position to an up position, in said up position, said needle holder is movable to cause said needle to protrude outwards of said housing to pierce the subject to allow administration of the substance to the subject.

2. The needle assembly according to claim 1 , wherein said safety latch is pivotally mounted on a base about a pivot.

3. The needle assembly according to claim 2 , wherein said safety latch is arranged to selectively pivot in and out of a complimentary shaped groove formed in said base.

4. The needle assembly according to claim 1 , wherein said safety latch comprises a first arrestor at a distal end thereof and a second arrestor proximal to and spaced from said first arrestor, said first and second arrestors being arranged for selectively arresting motion of said needle holder.

5. The needle assembly according to claim 4 , wherein said safety latch initially impedes movement of said needle holder by being in said down position wherein said first arrestor abuts against an ear that projects from a bottom portion of said needle holder, thereby arresting movement of said needle holder.

6. The needle assembly according to claim 5 , wherein when said safety latch is placed on the subject, said safety latch moves to said up position such that said first arrestor moves away from said ear of said needle holder to permit movement of said needle holder.

7. The needle assembly according to claim 6 , further comprising a control button that has a shaft, wherein a slanted tongue protrudes from a periphery of said shaft at a lower end thereof, and wherein when said safety latch is placed on the subject and said control button is moved, said slanted tongue applies a force against a ramp formed on said needle holder, thereby causing said needle holder to move and to rotate as said needle moves outwards of said housing.

8. The needle assembly according to claim 7 , wherein said needle holder rotates sufficiently so that said ear is arrested by said second arrestor.

9. The needle assembly according to claim 7 , wherein moving said safety latch off the subject causes said second arrestor to move away from said ear and causes said needle holder to continue to rotate due to said slanted tongue still applying a force on said ramp, wherein said needle holder rotates until said slanted tongue moves off said ramp, whereupon said needle holder moves so that said ear gets caught on a shoulder formed on said housing, thereby trapping said needle in said housing.

10. The needle assembly according to claim 7 , wherein when said control button is moved so that said slanted tongue applies the force against said ramp, said control button becomes locked in said housing.

11. The needle assembly according to claim 1 , wherein said safety latch is biased to said down position by a biasing device.

12. The needle assembly according to claim 11 , wherein said biasing device is a spring.