SAFETY I.V. CATHETER ASSEMBLY
FIELD OF THE INVENTION
This invention relates to the catheter assembly and more particularly to a safety intravenous catheter assembly to place the catheter into the human body reducing the likelihood of the accidental needle-stickiness injuries and infections.
BACKGROUND OF THE INVENTION
Catheter insertion devices are well known in the art. When a catheter is inserted into a patient for the intravenous delivery of a fluid, a disposable needle passing through the catheter cannula is utilized to make a puncture to permit entry of the tip of the cannula/needle into the patient. The needle is then withdrawn leaving the catheter in place either for a direct hook up to a bottle of fluid to be delivered, or to be capped for later use. The needle which is now contaminated with blood or other body fluid must be disposed of without creating a risk of needle sticks to medical personnel which are engaged in the operation of inserting a catheter. There are different kinds of withdrawn mechanism in the catheter assembly. Behind the mechanism, there are two basic objectives, one is safe removal of the needle, and another is disposal of the needle. The withdrawn of the needle should be as safe so that no harm to the paramedic or patient should occur. In the process of disposal, the needle should be deposed in a way leaving no risk of any kind of infection to anybody. Keeping these objectives in mind, the catheter assembly is designed. One more objective is, that catheter assembly should be simple in use, economical and should be capable of covering less space while in non use state. After use, a danger to clean up and medical waste disposal personnel continues if the used needles are not rendered harmless in some way. Caps or covers that can be mounted over the needle are not a satisfactory solution because they must be put in place and can come loose and expose the used needle.
In prior art, several patents for the cannula assembly with various structures and features can be found. Stocking et al have the US Pat. No. 5,704,914 discuss about a catheter assembly disclosed which includes a flexible catheter, a hub attached to the catheter which defines a lumen and an adjoining flash back chamber which communicate with the catheter, and a flexible resilient diaphragm attached to the hub through which a hypodermic needle such as a catheter introducer needle can be passed. The diaphragm

prevents a liquid, such as blood, which has been introduced into the hub lumen from
flowing past the diaphragm and beyond the hub when the diaphragm is unpenetrated. A
hollow tubular body may also be included to which a cannulated catheter needle can be
either stationarily or movably attached. The body is removably attached to the hub behind
the diaphragm. If movably attached to the body, the needle has a retracted position fully
recessed within the body for safe storage and an advanced operative position extending
through the diaphragm, hub and catheter. A needle occluding member may also be
provided to prevent a liquid such as blood from flowing through the needle into the body.
The member may be a movable guide wire or a stationary obturator member. A liquid
outlet port can be provided on the side of the hub and a multi-position stop cock can be
mounted on the hub to direct liquid flow from the catheter to the side port while blocking
flow toward the diaphragm and vise versa. Shaw et al, have their US Patents No. 5,989,220
discloses a self-retracting IV catheter introducer automatically retracts the catheter needle
safely within housing when the connector attached to the cannula is separated from the
housing after the cannula has been inserted into a patient. In one embodiment the housing
comprises a retraction tube enclosing a retraction body having a rear portion mounted
within the retraction tube and a front portion carrying a needle and extending through an
opening in the front of the retraction body. A connection surface on the exposed front of
the retraction body is frictionally engaged with a corresponding connection surface on the
connector. Abutting surfaces between the connector and the retraction tube serve as stops.
Releasable frictional engagement of the connection surfaces prevents retraction. Shaw et al
revealed another invention through U.S. Pat. No. 5,817,058 wherein there is a retractable
catheter introducer structure includes a stepped housing and a retractable needle holder.
The head of the needle holder is held in a first embodiment by means of a plunger tube
having a landed front opening and in a second embodiment wherein the head of the needle
holder is possessed of a surrounding ring member which can be pressed upon and released
by the open mouth of an elongated tube. A catheter needle extends from the front of the
housing to which a catheter assembly is removably attached. Both embodiments provide
one handed operation. Retraction is triggered by pulling on the housing with the plunger
tube backed against the palm of the hand to release the needle holder. Until the introducer

structure is separated, the catheter assembly remains attached to the housing after retraction is triggered giving the operator greater control by reducing uncontrolled fluid egress.
Isaacson et al has US Pat No. 5573510 whereby a safety intravenous catheter assembly is provided by interconnecting a safety receptacle for a retractable intravenous needle with a catheter that carries the needle and is advancible into a vein punctured by the needle. A coupling that is removably fastened to the catheter has an elongate stem portion that extends backwardly into the safety receptacle past a needle-stopping member within such receptacle. Such needle-stopping member is active to normally prevent backward movement of the needle into the receptacle. However, ultimate forward movement of the coupling with respect to the needle-stopping member following catheter emplacement into the vein permits movement of such needle-stopping member to non-stopping position, so that a tensioned spring can automatically urge the needle backwardly to a position wholly within the safety receptacle that protects against any accidental pricking, whereupon such receptacle, with its protectively contained needle, is discardable following removal of the coupling and the protectively encased needle from the emplaced catheter to prepare the catheter for IV connection and to prevent reuse of the contaminated needle. The needle-stopping member may be a stop gate that is cammed into open position or that is provided with a spring tensioned to open the gate when the rearward end of the coupling stem has passed through it in the manual advancement of the catheter into emplaced position in a vein of a patient.
Other prior arts also known for the retractable catheter assembly with various structures and features. Rodd et al, have the patent No. NZ544485, discuss about their invention relating to "cannula/catheter introducer with retractable needle'. Shaw et al, have their patents No. HK1078035, and US Pat No. 6,872,193 disclose the "IV catheter introducer with retractable needle". Shaw et al, have their another patent No. HK1066491 with "Self-retracting IV catheter introducer". Pressly Sr. et al revealed their invention as U.S. Pat. No. 6942652 wherein Retractable I-V catheter placement device is given including an intravenous catheter placement device. Chang et al has US Pat No. 6322537 with the title Safety intravenous catheter wherein a medical IV catheter is described.

The above prior arts are used to place the catheter for the intravenous activities. But it has been observed that still there is a requirement of the catheter assembly which can be useful for placing the catheter safely avoiding any infection to any human being including medical personnel, should be simple in structure, economical and should cover lesser space as compare to existing ones. By overcoming the drawbacks, the present invention is provided which may be useful from every aspect as stated above.
SUMMRY OF THE INVENTION
The present invention is directed to the intravenous catheter assembly which is used for the successful placement of the catheter into the human body. The objective of the catheter assembly is to place the catheter into the human body or vein safely without any harm to the patient or medical personnel. Another object of the catheter assembly is to dispose the needle/cannula unit avoiding any kind of infection to anybody who comes in its contact after its use. Moreover, there is one more object of the invention as to provide a catheter assembly with a simple structure which covers less space in its non use condition as compared to the usable condition. The catheter assembly includes two sub assemblies, one is catheter unit and another is housing unit. The catheter unit has a catheter shaft, catheter hub and catheter head. The catheter shaft is designed of a thin tubular shape structure insertable into the human body through its distal tip with the external support. The catheter shaft is insertably adhered through its rear end into the catheter hub, which is further studded into the catheter head. The housing unit has a cannula unit and tubular unit designed with three tubular members which frame a unit with proper engagement with each other. The connection between the diameters or circumferences of all three members is as: outer tubular member > middle tubular member > inner tubular member. As engagement, the inner tubular member slidably moves inside the body of the middle tubular member along with its length in the similar way as a piston moves inside the cylinder. However, the middle tubular member slidably moves inside the outer tubular member in the same way as a piston moves inside the cylinder. The cannula unit, including a needle hub and stainless-steel needle/cannula extending at front end of needle hub, occupies the tubular unit through its front end insertably into the rear opening of inner tubular member of tubular unit. The needle hub of cannula unit is fixed at its cork shaped head or base which is stuffed into the

rear end of outer tubular member of tubular unit. The cork shaped head act as a barrier for the backward direction of the inner & middle tubular members beyond the length of outer tubular member.
The middle tubular member includes a pair of wings formed at its rear outer surface and outer tubular member has a ring shaped stopper means formed inside front end. While moving in forward direction inside the body of the outer tubular member, the middle tubular member hooks up at its rear edge through the help of its wings and ring shaped stopper means of outer tubular means. The inner tubular member and middle tubular member include a pair of wings & ring shaped stopper means at the rear outer surface & inside front end. On moving in forward direction inside the body of the middle tubular member, the inner tubular member hooks up at its rear edge through the help of its wings and ring shaped stopper means of middle tubular member. When middle & inner tubular members of unit move in forward and backward direction inside the body of outer & middle tubular members respectively, the cannula unit remains stable at its base. The catheter unit is fitted through catheter head to the nose mounted at the front end of inner tubular member.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a plan view of intravenous catheter assembly, thus illustrating the preferred embodiment of our invention.
FIG. 2 shows a longitudinal cross-sectional view of intravenous catheter assembly.
FIG. 3 shows the cross sectional view of intravenous catheter assembly on the line of E-E of FIG. 2.
FIG. 4 shows the longitudinal cross-sectional view of middle tubular member of intravenous catheter assembly and its cross-sectional view on the line of G-G.
FIG. 5 shows the longitudinal cross-sectional view of inner tubular member of intravenous catheter assembly and its cross-sectional view on the line of H-H.
FIG. 6 shows the longitudinal cross-sectional view of outer tubular member of intravenous catheter assembly and its cross-sectional view on the line of J-J.
FIG. 7 shows a plan view of cannula unit of intravenous catheter assembly.

FIG. 8 & 9 shows the cross-sectional views of cannula unit on the line of P-P & 0-0 respectively of FIG 7.
FIG. 10 shows a longitudinal cross-sectional view of cannula hub of intravenous catheter assembly.
FIG. 11 shows the cross-sectional view of cannula hub.
FIG. 12 shows the longitudinal cross sectional view of catheter unit of intravenous catheter assembly.
FIG. 13 shows the cross sectional view of catheter unit of intravenous catheter assembly on the line ofH-H of FIG. 12.
FIG. 14 shows the cross sectional view of catheter unit of intravenous catheter assembly.
FIG. 15 shows a plan view of catheter shaft of catheter assembly.
FIG. 16 shows the longitudinal cross-sectional view of first stage opening of intravenous catheter assembly.
FIG. 17 shows a close up view of portion A of Fig 16.
FIG. 18 shows the longitudinal cross-sectional view of second stage opening of intravenous catheter assembly.
FIG. 19 shows a close up view of portion A of Fig 18.
FIG. 20 shows the longitudinal cross-sectional view of third stage opening of intravenous catheter assembly.
FIG. 21 shows a close up view of portion A of Fig 20.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Figs. 1 illustrate the Intravenous (I.V.) catheter assembly of invention in its normal state with the catheter unit X1 and housing unit X2. The catheter unit X1 remains attached at its head with the housing unit X2 and its distal tip is covered with cap or lid 3. Figs. 2 & 3 show the longitudinal cross sectional view & cross sectional view of the catheter assembly before the cannulation. All the components of the said catheter assembly can be seen in this view. Figs 4-11 describe the housing unit X2 with the detailed view of all its components. Figs. 12-15 illustrate structure of the catheter unit of the intravenous catheter

assembly. Figs 16-21 demonstrate all three possible opening stages of the Intravenous catheter assembly.
As shown in Fig 2, the housing unit X2 of Intravenous (I.V.) catheter assembly
includes a cannula unit and tubular unit designed with three tubular members. All these
three tubular members are assembled in a way that the middle tubular member 8 slidaly
moves in both ways within the outer tubular member 7 along its length. One more, inner
tubular member 9 of the housing X2 moves slidably within the middle tubular member 8 in
forward and backward direction along its length. The cannula unit occupies the inner
tubular member 9 through its base or head 11 at the outer rear end of outer tubular member
7. Fig 4, 5 & 6 show all three tubular members as outer tubular member 7, middle tubular
member 8 & inner tubular member 9. The outer tubular member 7 has a pair of rectangular
shaped slots 16 at the rear end which have its narrow openings at the edge or
circumference. These slots have been designed at the said circumference with equal
distance. At the inside front end of the outer tubular member 7, there is a ring shaped
stopper means 17 near the front edge. The middle tubular member 8 has a pair of wings 12
formed in the rectangular shaped slots at the rear end. The middle tubular member 8 has a
ring shaped stopper means 13 also at its inside front end in similar way as the outer tubular
member has. The inner tubular member 9 is designed with another pair of wings 14 in the
rectangular shaped slot at the outer rear end. As a part of process, the middle tubular
member 8 is insertably fitted into the outer tubular member 7. The said middle tubular
member 8 is inserted from its front side into the first tubular member 7 through its rear
opening. At the next step, from the front end, the inner tubular member 9 is inserted in this
unit though its rear end into the rear opening of middle tubular member 8. Now inner
tubular member 9 can slidably move inside the middle tubular member 8 along its length
and middle tubular member 8 can slidably move inside the body of outer tubular member 7
along its length. This tubular sub assembly engages all tubular members and all members
make a unity during the slidable movement. To keep all tubular members engaged with
each other, there have been provided the stopper means, hitches, wings and locking means,
which may be explained hereinafter. In the subassembly, the cannula unit (shown in Fig 7)
is liberally inserted through its distal tip from the rear entry of the inner tubular member 9.
On insertion of the cannula unit, the cannula 1 & cannula hub 10 cross the passageway of

the inner tubular member 9 along the length of all tubular members and the distal tip comes out from the front end of inner tubular member 9. On fully inclusion of the cannula unit, the cork shaped cannula head 10' of cannula unit is insertably stuffed into the rear opening of the outer tubular member 7. There is pair of arrow shaped locking means 10" at the cannula head 10' which is fixedly inserted into the pair of slots 16 of outer tubular member 7. The arrow shaped locking means 10" is fixed into the locking slots 16 making the cannula head 10' unmoved. The cannula hub 10 of cannula unit occupies the tubular unit inside the inner tubular member 9 of subassembly of three tubular members and its head 10' stuffed into rear opening of outer tubular member 7 and work as the stopper for middle and inner tubular members for their backward motion beyond the rear edge of outer tubular member 7. For more illustration, the cross sectional views of the cannula unit has been shown in Fig 8 & 9. Also Fig 10 & 11 represent the longitudinal cross sectional view & cross sectional view of the cannula hub 10 and catheter head 10'. Both middle and inner tubular members can move slidably into the backward motion but can not move beyond the head 10'. For holding middle tubular member 8 during the forward motion within the outer tubular member 7, the outer tubular member 7 includes a ring shaped stopper means 17 at the inside front end. Also, the middle tubular member 8 has a pair of wings 12 formed in a rectangular shaped slot. On the forward movement of the middle tubular member 8, the wings 12 clasp against the ring shaped stopper 17. Due to this clasping of the wings 12 by stopper means 17, the middle tubular member 8 cannot leave the outer tubular member 7 beyond its length during the slidable movement. The middle tubular member 8 also has a ring shaped stopper means inside its front end which act as clasping member for a pair of wings 14 formed at the outer surface of inner tubular member 9. At the time of forward movement, the inner tubular member 9 is stopped through these wings 14 and do not leave its associated member 8 at the end of its length. A nose 15 is insertably mounted over the outer front end of inner tubular member 9. The outer circumference of the inner tubular member 8 is equal to the inner circumference of nose 15, which makes nose 5 insertable through its rear end over the front end of the inner tubular member 9. The front end and rear end of the nose 15 is divided by a round plate shaped divider 6. The diameter of front end of the nose is smaller than its diameter of rear end. The front end of nose 15 is fittedly insertable into the cavity of the catheter head 5 of catheter unit.

Figs 12-15 represent the structure of catheter unit X1. The catheter unit is assembled with catheter head 5, catheter hub 4, catheter shaft 2 & catheter lid 3. As shown in Fig 12, the catheter shaft 2, shown in Fig 15 also, has a distal and proximal end insertably mounted in the catheter hub 4. The catheter hub 4 normally has funnel or V shaped structure. The catheter shaft 2 is mounted with its proximal end inside the hole made on the tip of catheter hub 4. The V shaped catheter hub 4 along with the catheter shaft 2 is fitted inside the V shaped cavity of the catheter head 5. In this step, the catheter shaft protrudes through its tip from the front end through a front hole of catheter head 5. In this sub assembly or catheter unit, there is a straight passageway which is formed by the cavity of catheter head 5, cavity of catheter hub 4 and vessel of catheter shaft 2. The fluid can travel inside this passageway which is injected into the human body through the opening made on the distal tip of catheter shaft 2. The inner circumference of the cavity of catheter head 5 is almost equal to the outer circumference of the front end of nose 15.
With reference to the Fig 2, middle tubular member 8 remains inside the outer tubular member 7 along its length and inner tubular member 9 remain inside the middle tubular member 8 along its length. At the same time the cannula hub 10 occupies the inner passageway of the inner tubular member 9. However, the cannula 1 remains outside the subassembly or housing at the front side. The exposed cannula 1 is covered through the catheter shaft 2 after the catheter head inserted through the distal tip of the cannula 1 and fitted at the nose 15. This is the ready-to-use state and shortest length of the catheter assembly. Due to this shortest length it covers lesser space and useful for the transportation also.
In Fig 2, the I.V. Catheter assembly has been shown in ready-to-use state with its shortest length. After removing the lid 3 of the catheter assembly, the cannula 1 along with the catheter shaft 2 is inserted into the human vein for puncturing it. On successful placement of the catheter, the outer tubular member 7 of housing X2 is held with the fingers and one of the fingers is placed at the divider 6 of the nose 15 and the outer tubular member 7 is pulled back (as shown in Fig 16). Figure 16 represents the first stage opening of the catheter assembly. At this stage on pulling back the outer tubular assembly 7, the inner tubular member 9 comes out from the tubular unit and outer tubular member 7

retracts the needle from the catheter. In Fig 17, it can be seen that the cannula tip is still in the range of catheter head. Fig 18 shows the second opening stage of the catheter assembly. In this stage, the outer tubular member 7 is pulled back retracting the cannula more than retraction of first stage from the range of catheter head 5. At this stage the housing unit X2 appears in its fullest length and cannula 1 completely leaves the catheter. Fig 19 shows the close up view of the portion "A" showing the cannula 1 across the middle tubular member. Fig 20 represents the third stage opening of the catheter assembly in which all members of housing X2 are extended with the fullest length and the housing X2 is removed from the catheter. At second & third stage of opening of assembly, in the fullest length, the wings 12 & 14 of the middle and inner tubular members 8 & 9 hook up with the ring shaped stopper means 17 & 13 respectively and unite to form a sub-assembly. This sub assembly of housing in its extended form keeps the infected cannula assembly safe and unexposed avoiding any probability which may cause infection to any human being. Without external force the extended assembly can not shorten to its original length, therefore it is disposed in the same state.

Claims
1. A safety intravenous catheter assembly, comprising:
a tubular unit having three tubular members, said tubular members engaged with each other, the middle tubular member moves slidably in backward & forward direction inside the body of outer tubular member along its length and inner tubular member moves slidably in backward & forward direction inside the body of middle tubular member, and
a cannula unit having its associated members engaged with tubular unit, the cannula unit includes a cannula hub extending at its head and head further includes a pair of locking means.
2. The safety intravenous catheter assembly as claimed in claim 1, wherein the diameter of inner tubular member is less than the diameter of middle tubular member, and the diameter of middle tubular member is less than the diameter of outer tubular member.
3. The safety intravenous catheter assembly as claimed in claim 1, wherein the outer tubular member includes a slot with narrow opening at its outer rear end and a ring shaped stopper means at its inner front end.

4. The safety intravenous catheter assembly as claimed in claim 1, wherein the middle tubular member includes a pair of wings at its outer rear end and a ring shaped stopper means at its inner front end.
5. The safety intravenous catheter assembly as claimed in claim 1, wherein the inner tubular member includes a pair of wings at its outer rear end and a nose mounted over the outer front end of inner tubular member.
6. The safety intravenous catheter assembly as claimed in claim 1, wherein a pair of locking means mounted at the cannula head of cannula unit has the arrow shaped structure.
7. The safety intravenous catheter assembly as claimed in claim 5, wherein the nose has its front and rear part which is divided by a divider.
8. The safety intravenous catheter assembly as claimed in claim 1, wherein the cannula
unit is insertably fitted into the inner tubular member of tubular unit and cannula head
is stuffed into the rear opening of outer tubular member.
9. The safety intravenous catheter assembly as claimed in claim 7, wherein the outer
circumference of the front end of the inner tubular member is almost equal to the inner
circumference of the rear part of nose.
10. The safety intravenous catheter assembly as claimed in claim 7, wherein the diameter
of the front end of nose is less than the diameter of the rear end of nose.
11. The safety intravenous catheter assembly as claimed in claim 7, wherein the outer tubular member, middle tubular member & inner tubular member are cylindrical in shape and made of plastic material.