Patent ID: 8137287

Claim:
A device, comprising: a housing including a stop with a first contact portion and a second contact portion; a cannula having a portion in the housing; and a movable cannula block in the housing, the moveable cannula block attached to the cannula, the movable cannula block having a distal end with a face that includes a first portion and a second portion recessed relative to the first portion of the face, the recessed second portion disposed in alignment with the second contact portion of the stop such that movement of the cannula block towards the stop brings the first portion of the face of the cannula block into contact with the first contact portion of the stop and rotates the cannula block to bring the recessed second portion into contact with the second contact portion of the stop; wherein the housing includes ribs defining a channel that receives at least part of the cannula block, the channel having a channel width; and wherein the cannula block has a middle portion disposed proximally of the asymmetric distal end of the cannula block and a distal end width of the part of the cannula block received in the channel is greater than a width of the part of the cannula block received in the channel at the middle portion and less than the channel width; wherein the width of part of the cannula block received in the channel is a distance along a line perpendicular to the ribs defining the channel from an outermost surface on a first side of the part of the cannula block received in the channel to an outermost surface on a second side, opposite the first side, of the part of the cannula block received in the channel.