Automatic retractable lancet assembly

• US 4,388,925 A
• Filed: 03/23/1981
• Issued: 06/21/1983
• Est. Priority Date: 03/23/1981
• Status: Expired due to Term

• Current Assignee: Becton, Dickinson & Co
• Original Assignee: Becton, Dickinson & Co
• Inventors: Burns, James A.
• Primary Examiner(s): Thaler, Michael H.
• Application Number:
  US06/246,523
• Time in Patent Office: 820 Days
• Field of Search: 128/314, 128/315, 128/329 R, 128/329 A, 128/330, 128/638, 128/218 A, 128/218 F, 128/253, 128/770
• 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 5/15144 comprising driving means, e.g. a spring, for retracting the piercing unit into the housing

Abstract

An automatic retractable lancet assembly includes a housing with a sharp-pointed lancet movably mounted therein. A depressible plunger and slide mechanism actuates the movement of the lancet outwardly from the housing. After this outward movement is completed, the actuator elements become dissociated from further movement of the lancet. Subsequently, the lancet is automatically retracted back inside the housing by virtue of a spring element.

Claims

1. An automatically retractable spring lancet assembly for piercing human skin which assembly includes automatic release of the drive spring for retraction, characterized by

(a) a housing having an aperture;

(b) a plurality of elongate openings in said housing;

(c) a lancet mounted in said housing for reciprocable movement therein;

(d) a point on said lancet positioned adjacent the interior side of said housing aperture;

(e) a depressable plunger mounted for reciprocation in said housing in the end thereof opposite said housing aperture;

(f) the outer end of said plunger extending out of said housing for engagement;

(g) a sleeve slidable on said housing and positioned to engage said lancet in the piercing forward movement thereof;

(h) a first compressed spring extending between said housing and said sleeve for the piercing forward movement of said lancet upon engagement of said plunger;

(i) a second uncompressed spring extending between said lancet and said housing for the compression thereof and automatic retraction of said lancet after the said piercing forward movement thereof;

(j) cooperating means extending between said plunger and said housing for automatically disengaging said first spring from said lancet after said lancet completes its piercing movement for allowing the automatic retraction of said lancet back through said housing aperture;

(k) a flexible skirt positioned on said housing for maintaining said sleeve in position for compressing said first spring; and

(l) a plurality of flexible arms adapted to flex outwardly upon depression of said plunger and contact said flexible skirt and cause said skirt to flex outwardly to thereby become disengaged from said sleeve thereby releasing the restraining force applied to said first spring so that said sleeve moves forward to cause the said forward piercing movement of said lancet.

2. The assembly of claim 1 wherein said sleeve is positioned to restrain said first spring in a compressed condition before said plunger is depressed.

3. The assembly of claim 1 wherein said sleeve includes a plurality of inclined surfaces adapted to be engaged by said plunger flexible arms upon depression of said plunger for causing said flexible arms to flex outwardly.

4. The assembly of claim 1 wherein said housing includes a plurality of longitudinally extending openings circumferentially spaced around its periphery and said sleeve includes a plurality of feet with one each extending through one of said openings for engaging said lancet.

5. The assembly of claim 4 wherein said feet are included on a plurality of flexible legs on said sleeve, said legs adapted to flex outwardly upon distal movement of said sleeve whereby said feet become disengaged from said lancet after said second spring has become compressed, said disengagement of said feet thereby releasing the restraining force applied to said second spring so that said second spring becomes decompressed and thereby automatically retracts said lancet back inside said housing.

6. The assembly of claim 5 wherein said housing includes a plurality of inclined surfaces adapted to be engaged by said flexible legs upon distal movement of said sleeve for causing said legs to flex outwardly.

7. The assembly of claim 1 wherein said housing and said plunger are made of plastic and said lancet is made of metal.

8. The assembly of claim 1, further characterized by

(a) said housing, said plunger and said lancet are cylindrical and coaxial.

9. An automatic retractable lancet assembly comprising:

a substantially cylindrical housing having an aperture;

a sharp-pointed lancet movably mounted in said housing with its point lying adjacent the interior side of said aperture;

a depressible plunger coaxially mounted inside said housing in the end thereof opposite from said lancet including a plurality of flexible arms adapted to flex outwardly upon depression of said plunger;

a first spring mounted inside said housing restrained in a compressed condition, before said plunger is depressed, by a slidable sleeve positioned on said housing, said sleeve including a plurality of flexible legs each having a projecting foot thereon for engaging said lancet;

a flexible skirt positioned on said housing for maintaining the sleeve in position for compressing said first spring and adapted to flex outwardly upon the outward flexing of said plunger arms so that said skirt becomes disengaged from said sleeve to release the restraining force applied to said first spring causing said sleeve to move distally and thereby move said lancet outwardly from said housing; and

a second spring mounted inside said housing in a substantially decompressed condition before said plunger is depressed said second spring adapted to become compressed after said sleeve moves distally and causes outward movement of said lancet, said flexible legs of said sleeve adapted to flex outwardly after distal movement of said sleeve whereby said feet become disengaged from said lancet after said second spring has become compressed, said disengagement of said feet thereby releasing the restraining force applied to said second spring so that said second spring becomes decompressed and thereby automatically retracts said lancet back inside said housing.