Needle safety shield

A needle safety shield 10 for use with a syringe 10 having a barrel 14, a needle and a plunger rod 16. The safety shield 10 has a first tube 22. A second tube 26 is arranged for sliding movement within the first tube 22. A pin 46 is connected to one of the first and second tubes 22, 26. An activation ring 32 has a stop 72. A drive spring 34 biases the activation ring 32 in a proximal direction to place the stop 72 in engagement with the pin 46 to retain the first and second tubes 22, 26 in a retracted configuration. The movement of the plunger rod 16 to engage the activation ring 32 compresses the drive spring 34, moving the activation ring 32 distally, and moving the stop 72 out of engagement with the pin 46, allowing the drive spring 34 to move the first and second tubes 22, 26 into an extended configuration.