US Patent 7914546 Lancet

Plastics material injected through an entry point of a mould at the location (8) is caused to deflect around a pin which creates the hole (14) in a guard (5), so as to increase the balance of flow of material to either side of the pin (9). In order to minimize the tendency for the plastics material to bend out of shape the tip of the needle embedded within an enlarged portion (13) the mould is formed such that the mould material is initially encouraged to divide and flow through outer thickened regions (10) surrounding a thinner portion. At point (12) the plastics material is therefore caused to slow down resulting in greater equalization of the flow speed of the plastics material to either side of the needle tip.