Medical dispensing device

A method of dispensing a medical substance, the method comprising:

• actuating a rod distally a first distance to a maximum distal position using a first engager by applying a force upon a trigger of a medical dispensing device, the medical dispensing device comprising:
• a frame comprising a housing and a handle that extends from a proximal portion of the housing;
• the rod positioned within the housing of the frame;
• the trigger affixed to the frame and configured to move relative to the handle;
• the first engager distal to a first portion of the trigger, wherein the first engager moves distally relative to the housing when the trigger moves axially toward the handle and the first engager is configured to move distally relative to the housing when the trigger moves axially toward the handle and move proximally relative to the housing when the trigger moves axially away from the handle, wherein the first engager is configured to engage the rod as the first engager moves axially relative to the housing such that the rod undergoes a distal force when the first engager moves distally and the rod undergoes a proximal force when the first engager moves proximally;
• a distal hard stop limiting axial rotation of the trigger towards the handle, wherein the maximum distal position of the rod is defined by the distal hard stop;
• a compression spring that is engaged with the first engager;
• a proximal hard stop limiting axial rotation of the trigger away from the handle, wherein the compression spring presses the first engager into the trigger such that at least one of the trigger or the first engager is configured to rest against the proximal hard stop when the trigger is not actuated;
• a second engager that is configured to move axially relative to the housing, wherein the second engager limits proximal movement of the rod when the second engager is in contact with the rod at the actuated position;
• a second engager hard stop that defines an actuated position of the second engager relative to the housing;
• and
• a movement transfer assembly configured to transfer movement of the trigger to the second engager such that the second engager is configured to move distally when the trigger has moved axially towards the handle more than a threshold amount, wherein the movement transfer assembly includes a transferring member that distally moves the second engager relative to the housing as the trigger moves axially towards the handle after the trigger has moved axially towards the handle more than the threshold amount and until the distal hard stop limits axial rotation of the trigger towards the handle, wherein the second engager is configured to enable the rod to proximally move until the rod is in contact with the second engager while the second engager is at the actuated position;
• reducing a force upon the trigger such that at least one of a trigger or a first engager rests against the proximal hard stop, wherein reducing the force upon the trigger results in the rod proximally moving a second distance, wherein the second distance is less than the first distance.

A medical dispensing device for dispensing materials by actuating a rod distally toward a material reservoir, the medical dispensing device comprising:

• a frame comprising a housing that houses the rod and a handle that extends from a proximal portion of the housing;
• a trigger affixed to the frame and configured to pivot axially about a pivot point towards and away from the handle;
• a distal hard stop limiting axial rotation of the trigger towards the handle;
• a first engager that is configured immediately distal to a first portion of the trigger, wherein the first engager moves distally relative to the housing when the trigger pivots axially toward the handle and the first engager moves proximally relative to the housing when the trigger pivots axially away from the handle, wherein the first engager is configured to engage the rod as the first engager moves axially relative to the housing such that the rod undergoes a distal force when the first engager moves distally and the rod undergoes a proximal force when the first engager moves proximally;
• a second engager that is configured to move axially relative to the housing, wherein the second engager limits proximal movement of the rod when the second engager is in contact with the rod at an actuated position of the second engager;
• and
• means for absorbing and transferring movement of the trigger onto the second engager such that the second engager only moves if the trigger has pivoted axially towards the handle more than a threshold amount, wherein the means for absorbing and transferring movement of the trigger onto the second engager distally moves the second engager along the housing as the trigger pivots axially towards the handle after the trigger has pivoted axially towards the handle more than a threshold amount and until the distal hard stop limits axial rotation of the trigger towards the handle, wherein the means for absorbing and transferring movement of the trigger onto the second engager defines both a maximum distal position of the rod and the actuated position of the second engager.