Hypodermic needle guard

Details Hypodermic needle guard Hypodermic needle guard

2001-06-08

2002-11-26

Mendez, Manuel (Department: 3763)

Surgery

Means for introducing or removing material from body for...

Treating material introduced into or removed from body...

Reexamination Certificate

active

06485468

ABSTRACT:

FIELD OF THE INVENTION
This invention relates generally to insuring the safe disposal of hypodermic needles. In particular, this invention relates to a device that is storable on the needle and that automatically locks over the end of the needle when the tip of the needle has been retracted within the interior of the device.
BACKGROUND OF THE INVENTION
The danger of infection from accidental contact with the tip of a used hypodermic needle has long been recognized and is well documented. In most procedures, the greatest avoidable risk of accidental needle puncture, also referred to as a “needlestick”, occurs during handling of the used needle, when an operator generally inserts the used needle into a protective sheath for disposal. This action usually requires the operator to move the hand which holds the sheath toward the pointed tip of the needle, and any inaccuracy in this operation raises the possibility of a puncture. The risk of this is greatly increased if the operator is working under stress, such as time pressure or fatigue, or is handicapped by marginal eyesight or unsteady hands.
The problem of accidental needlesticks has recently engaged the attention of the United States Congress. The “Health Care Worker Needlestick Prevention Act” was recently introduced in both the House of Representatives and the Senate. The Act, if passed, would require the Secretary of Labor, acting through the Department of Labor's Occupational Safety and Health Administration, to amend OSHA's bloodborne pathogens standard to require that, among other things, employers utilize “engineered sharps injury protections.” The Act generally defines “engineered sharps injury protections” as physical attributes that effectively reduce the risk of a needlestick injury and that are built into needle devices or other sharp, non-needle devices that are encountered in a health care setting.
A number of such “engineered sharps injury protections” have been developed for needle devices to deal with the general problem of needlesticks. One such device is disclosed in U.S. Pat. No. 5,322,517 to Sircom et al., entitled “Disposable Automatic Hypodermic Needle Guard” (“the Sircom Patent”). The Sircom Patent discloses several embodiments for a protecting device for covering the tip of a needle. The protecting device takes the form of a protective guard which is initially stored on the barrel of the needle and remote from its tip, and which is displaceable to a position enclosing the needle tip where it automatically locks in this position, serving as a protecting means for the needle tip. In the embodiment shown in
FIGS. 35 through 39
, a locking device includes a pivoting or lever arm or lever
101
of stiff material, formed in the general shape of a broad U of unequal proportions, with the longer vertical leg, referred to as the locking plate
102
, provided with a hole
103
of slightly larger diameter than that of the needle shaft
1
sufficient to allow the locking plate
102
to “cant” on the needle
1
, as shown in
FIG. 39
of the Sircom Patent.
A helical compression spring
104
is contained in a largely compressed state in longitudinal cavity
105
within the guard body
106
, with its free end
125
pressing against the locking plate
102
of the lever
101
and urging the level
101
axially against the sloping internal face
107
of body
106
, making contact at pivot point
108
. The turning moment of the spring force tends to rotate the level
101
in a counter-clockwise direction about the pivot point
108
, but the shorter vertical leg
109
of the lever
101
, referred to as the latching or locking leg, prevents rotation by making contact with the needle shaft
1
at point
110
.
The slope of the face
107
in relation to the geometry of the lever
101
is chosen to develop a component of reaction force that acts at the pivot point
108
in a downward direction against the lever
101
, equal and opposite to the upward reaction force against the lever at the point
110
. This balancing of vertical forces against the lever
101
substantially removes any radial force between the needle shaft
1
and the walls of the hole
103
into lever
101
, thereby reducing axial frictional drag between the needle shaft
1
and the lever
101
when moving the guard device axially along the needle shaft.
When the needle shaft
1
is withdrawn into the protective guard and passes the point of contact with the sensing end of the locking leg
109
of the lever or pivot arm
101
, the lever
101
rotates in a counter-clockwise direction about the ivot point
108
under the urging of the spring
104
, which rotates the locking plate
102
until further rotation is prevented by the axial misalignment of the hole
103
and the needle shaft
1
.
A problem with the protective guard described in the Sircom Patent is its complexity. For example, the protective guard requires a critical geometry to. ensure that the lever
101
locks on the needle shaft
1
when the needle shaft
1
is retracted into the protective guard. In establishing this critical geometry, care must be taken to ensure a particular relationship between the thickness
111
of the latch
101
, the distance
112
between the pivot point
108
and the center of the needle shaft
1
, the diameter of the hole
103
, the diameter of the needle shaft
1
, and the coefficient of friction between the latch
101
and the needle shaft
1
.
Another problem with the protective guard described in the Sircom Patent is that the locking leg
109
of the lever
101
does not provide a mechanism whereby a wire guide can pass therethrough after the needle shaft
1
has been withdrawn into the protective guard. It is desirable to enable a wire guide to pass through the protective guard after the needle tip has been retracted into the protective guard so that the wire guide can facilitate the advancement of a catheter into the blood vessel of a patient.
SUMMARY OF THE INVENTION
The present invention is directed to an apparatus that satisfies the need for a needle guard that is easy to manufacture and that permits the passage of a wire guide therethrough even after the needle tip has been retracted into the interior of the needle guard.
A device for inhibiting unintentional contact with the tip of a needle that has features of the present invention includes a housing having an interior cavity. A portion of the needle extends through the cavity and the tip of the needle is located outside of the housing during use of the needle. A pivoting member is located within the cavity and defines a distal opening and a proximal opening. These openings are sized to allow the needle to pass through the openings in the pivoting member. The pivoting member is canted into locking engagement with the needle to prevent further movement of the needle when the needle tip is within the cavity and the needle is withdrawn from the distal opening of the pivoting member.
In accordance with another embodiment of the present invention, a device for inhibiting unintentional contact with the tip of a needle includes a housing having an interior cavity. A portion of the needle extends through the cavity and a tip of the needle is located outside of the housing during the use of the needle. A pivoting member is located within the cavity, and defines a distal opening and a proximal opening, both of which are sized to allow the needle to pass through the pivoting member. The pivoting member further defines a slot that communicates with the distal opening and has a dimension that is insufficient to permit passage of the needle therethrough. The pivoting member is canted into locking engagement with the needle to prevent further movement of the needle when the needle tip is within the cavity and the needle is withdrawn from the distal opening of the pivoting member.
In accordance with a further embodiment of the present invention, a device for inhibiting intentional contact with the tip of a needle includes a housing having an interior cavity. A portion of the needle extends through the cavity and a

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