Lancet injector

• US 4,503,856 A
• Filed: 04/07/1983
• Issued: 03/12/1985
• Est. Priority Date: 06/29/1981
• Status: Expired due to Term

• Current Assignee: Sherwood Services AG
• Original Assignee: Sherwood Medical Company (Medtronic Plc)
• Inventors: Cornell, William D., Evans, Carnot
• Primary Examiner(s): Yasko, John D.
• Application Number:
  US06/483,074
• Time in Patent Office: 705 Days
• Field of Search: 128/314, 128/315, 128/333, 128/329
• US Class Current: 606/182
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150412 Pointed piercing elements, e.g. needles, lancets for piercing the skin blade-like piercing elements A61B5/150442
• CPC Class Codes: A61B 5/15113 Manually triggered, i.e. the triggering requires a deliberate action by the user such as pressing a drive button
• CPC Class Codes: A61B 5/15117 comprising biased elements, resilient elements or a spring, e.g. a helical spring, leaf spring, or elastic strap
• CPC Class Codes: A61B 5/1513 comprising linear sliding guides comprising tooth-shaped elements A61B5/15132
• CPC Class Codes: A61B 5/1519 comprising driving means, e.g. a spring, for propelling the piercing unit
• CPC Class Codes: A61B 5/15194 fully automatically retracted, i.e. the retraction does not require a deliberate action by the user, e.g. by terminating the contact with the patient's skin

Abstract

A lancet injector is provided which has a tubular housing, a slidable lancet holder in the housing, a compression spring connected between the holder and one end of the housing, and a holder control member extending through a longitudinal slot in the sidewall of the housing. The control member is operable to move the lancet holder to a latched retracted position against the force of the spring, release the holder so that it moves linearly under the force of the spring and inertia to a skin piercing position and then back to a neutral position in which the spring is in a free length condition.

Claims

1. A lancet injector comprising an elongate housing having a generally longitudinally extending slot in the sidewall thereof, a lancet holder longitudinally slidable in said housing and adapted to releaseably receive a lancet for piercing the skin, spring means in said housing having one end connected to said holder and the other end connected to a proximal end portion of said housing, and a control member extending through said slot and connected to said holder for manually moving said holder, said control member being movable to move said holder linearly in a proximal direction against the force of said spring means to a releasable retracted position thereby compressing said spring means, said control member being movable to release said holder from said retracted position so that the force of said spring means and the inertia of said holder during movement thereof moves said holder linearly in a distal direction to a lancet piercing position in which said spring means is tensioned so as to move said holder proximally from said piercing position to a neutral position where said spring means is in a free length neutral force condition, said control member being distally movable to move said holder to a lancet access position distally beyond said lancet piercing position.

2. The injector of claim 1 wherein said slot includes a first recess for receiving said control member and holding it and said holder against the compressive force of said spring means thereby latching said holder in the retracted position, and a second recess for receiving said control member and holding it and said holder against the tension force of said spring means for latching said holder in said lancet access position.

3. The injector of claim 1 or 2 wherein the distal end of said holder is distally beyond the distal end of said housing when said holder is in said lancet access position.

4. The injector of claim 1 or 2 wherein said spring means is a coil spring and the sole functional spring in the injector.

5. The injector of claim 1 or 2 wherein said slot includes a longitudinally extending slot portion connected at the proximal end with said first slot recess and having a wall at the distal end thereof, said control member being engageable with said wall to limit the distal movement of said holder after release thereof from said retracted position and define said lancet piercing position when said control member is engaged with said wall, said holder being movable from said piercing position to a neutral force position wherein said spring means is in the free length neutral force condition and proximal of said wall.

6. The injector of claim 5 wherein said slot includes a second longitudinally extending slot portion connected with said first named slot portion and said second recess, and said spring means is arranged to bias said holder in a rotary direction.

12. The injector of claim 1, 2, 8 or 10 further including an end cap removably connectable to the distal end of said housing and having an opening for movement therethrough of a needle point of a lancet connected to said holder during a skin piercing operation.

13. The injector of claim 1, 2, 8 or 10 further including a lancet having a handle and a needle point extending from the distal end of said handle, and wherein said holder includes a sleeve having an open distal end for slidingly receiving said handle in frictional engagement with the sidewalls of said sleeve.

7. A lancet injector comprising an elongate housing having an elongate chamber therein, a lancet holder linearly slideable longitudinally in said chamber and adapted to hold a lancet, spring means in said chamber, a slot in the sidewall of said housing extending generally longitudinally of said housing and having first and second recesses, a control member connected to said holder and extending through said slot to the exterior of said housing for manually moving said holder, said control member being movable to a latched retracted position into said first recess to thereby move said holder against the force of said spring means to a retracted position within said chamber wherein said spring means is in compression, said control member being movable from said latched retracted position in said first recess so that the force of said spring means effects linear distal movement of said holder and control member longitudinally to lancet skin piercing positions, said control member being distally movable longitudinally in said slot distally beyond its skin piercing position to a latched lancet access position in said second recess wherein said spring means is in tension and said holder is held against longitudinal movement by walls of said second recess and wherein said holder can be loaded with a lancet.

8. The injector of claim 7 wherein said holder extends distally outwardly of the distal end of said housing when said control member is in access position.

9. The injector of claim 7 or 8 wherein said spring means is fixedly secured at its opposite ends to said holder and a proximal end portion of said housing, respectively.

10. A lancet injector comprising an elongate housing, a lancet holder longitudinally slideable linearly in said housing and adapted to have a lancet releaseably connected thereto, a coil spring in said housing fixedly connected at one end to said holder and fixedly connected at the opposite end to a proximal end portion of said housing, said housing having an opening through the sidewall thereof, a manually operated control member connected to said holder and extending through said opening to the exterior of said housing for controlling the movement of said holder, said housing opening having sidewalls defining first and second longitudinally extending slots, said first slot being connected to and extending distally beyond said second slot, said second slot having a distal end wall, said sidewalls also defining a first recess disposed arcuately relative to said second slot and connected thereto, and a second recess adjacent the distal end of said first slot and connected to and spaced arcuately relative thereto, said control member being in a neutral position proximally of said distal end wall of said second slot when said spring is in its neutral force condition, said control member being movable proximally in said second slot from said neutral position into said first recess to thereby latch said holder in a retracted position with said spring compressed and urging said control member in a distal direction toward said first recess, said holder being movable under the forces of said spring from said retracted position in response to movement of said control member from said first recess to momentarily move said holder from said retracted position and said control member distally in said second slot to skin piercing positions in which the distal tip of a lancet when connected to said holder is moved distally of the distal end of said housing for piercing the skin of a patient when disposed adjacent the distal end of the housing, said control member being movable distally beyond said neutral position and engageable with said distal end wall of said second slot to limit the distal movement of said holder, said control member being movable from said neutral position thereof distally and linearly in said first slot and then into said second recess to thereby latch said holder in a lancet access position wherein a lancet may be inserted and removed from said holder, said spring being tensioned when said control member is in said second recess to urge said control member in a proximal direction towards said second recess.

11. The injector of claim 10 wherein said spring applies a rotary biasing force against said holder, and said spring is the only functional spring in the injector.