AU613871B2 - Monostroke syringe pusher for automatic parenteral injections with servo-control and programming - Google Patents

Description

J J

PCT

AU-AI-75153/87 ORGANISATION MONDIALE DE LA PROPRIETE INTELLECTUELLE Bureau internationtil 0 DEMANDE INTERINAW,)NALE PU C lV R- RA7R DE dLOERATION EN MATIERE DE BREVETS (PCT) (51) Classification interna iwml des 1revets9 y h~n~ oublication Internationale; WO 87/ 07843 A6IM 5/14 Al (43) Date de publication internationale: d~cemrbre 1987 (30.12,87) (21) Num~ro de la demnande Internationale: PCT/FRS7/00226 (22) Date de d~libt international: 1 (31) Num~ro (1e Ia demande prioritaire: (32) Date do priorit6: (33) Pays de prlorit6: 7 juin 1987 (17,06,87) 86/08781 8 juin l1986 (18.06.86)

FR

(71)(72) Diposants et inventeurs: HAZuiN, Bernard [FR/ FR]; 25, avenue Rapp, F-75007 Paris SAUSSE, Andr6 (FR/FR]* Q2, avenue Franklin Roosevelt, F- 92230 Sceaux (FR).

(74) Repr6sentant comnaun: HAZON, Bernard; 25, avenue Rapp, F-75007 Paris (FR), (81) Etats d~sigis: AT (brtvet europ~en), AU, BE (brevet europ~en), CH (brevet europ~en), DE (brevet europ~en), DK, FR (brevet eueop~en), GB (brevet europ~en), IT (brevet europ~en), J11, LU (brevet t:;trop~en), NL (brevet europ~en), SE (brevet europeen), us.

Publi~e &ev~c rapport de recherche internationale, 18FEB 1988

AUSTRALIAN

12 JAN 1988 PATEINT OPPICE

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(54)Title: MIONOSTROKE SYRINGIE 'qHEIR, FOR AUTOMIATIC PARENTERAL CONTROL AND PROGRAN4M NO INJECTIONS- WU~H SE~RVO- (54)Titre: DISPOSITIF POUSSE-SERINGUEl MONOCOURSE POUR TtQUES A ASSURVISSEMENT ET PROGRAMMATION (57) Abstract INJECTIONS PARENTERALES AUTUvIA, Moniostroke syringe-pusher f~or ambulatory medicinal injections with selfwcontained electric supply by means of r(echargeab~o batteries of a 7t motoreducing system which drives a coaxial 1 worm screw, This w,rm screw actuates a which provides fee the translation of the syringe 26 pistor,. T4t asse,,nbly is contained in it substan- t tially sealed rigid envelope which also provides 2 for the guiding or the carriage. The rotation angle 1 of the worm, screw corresponding to the delivery of the unit volume is controlled by two servocontrol loops, The delivery rate of boluses is controlled by a programming unit and/or a clock, An excessive pressure or a continuous, inadvertent operation or the motorce.tion unit sets thle Irrevocable backwvard retuen, ot thc device together with a sound alarm, (57) Abre'g6 Dispositif monocourse pousse-seringue pour injections m6dicani~itelt'scs ambultolres !i alimeuntation Olectrique autonome par batteries rechargeables d'unt motor~ducteur entraltlank une vis-sans-fin coaxiade. Cette vls-sahs~fin attaque un chariot assurant la translation du piston de lit seringve. Tout i'ensemble est contenu danis une eniveloppe rigide quasi- 6tanche servant aussi d~ gtuider to chariot. L'angle de rotaton, de [a vis-sans-rin correspondarit, dX a dllivrance du volume unitaire est contr6k6 par deux boucles d'asservissemertt, La fr~qucnce de d~livrance des bolus est contr~le par un pro, granimateur et/ou une hoiloge, (Ine pression extcessive aussi biert qu'un fonctionnemetnt continu intempeitif du motor6.

d t ucteur d~clencho le retour ardi~e Irr6yocable avea alarme sono re.

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SINGLE-STROKE SYRINGE-DRIVER DEVICE FOR AUTOMATIC PARENTERAL INJECTIONS WITH SERVO-CONTROL AND

PROGRAMMATION

Background of the Invention The control of the flowrate during injections, whether they be intravenous, intravascular or subcutaneous, with the existing single-use equipment, remains random even in the hands of a trained operator.

This is all the more true when, from the same syringe, a plurality of unitary volumes must be delivered either spread out in time or distributed in a plurality of sites. Whether it is question of a continuous or discontinuous flowrate, its control can be ensured only by that of the translation of the piston of the syringe.

This is why numerous devices for mediate translation have been proposed, using in general a screw or a rack of which the movement is controlled either by direct reading, or, better, by servo-control, whether this mechanism be driven directly by the operator as in French Patent No. 85/09015 or by a general and electrical servo-mechanism.

The utility of such devices is particularly obvious for so-called long-duration medical treatments such as repetitive administration of drugs such as antimitotics, antibiotics, hormones, particularly if it is CASE: 162,330 2 desired not to multiply the number of injections and consequently the number of cutaneous punctures.

In the present art of administration of such medicamental treatments, repetitive intravenous injections are generally resorted to. To that end, a venous perfusion by gravity is most often set up by means of a catheter or an intravascular needle permanently connected to a tube provided with a flowrate control means and into which are repetitively injected the drug or drugs in a zone which is perforatable and self-closing ad hoc. This technique, whose sole purpose is to prevent obturation of the catheter by coagulation of the blood, presents numerous drawbacks, particularly during the patient's displacements.

In fact, the maintenance of a constant pressure gradient between the perfusion bottle and the vascular system is random, even impossible, this causing blood to flow back into the tube, generating untimely coagulation and virtual impossibility of maintaining a sufficient flowrate of perfusion.

In the present invention, it is chosen to substitute for the pressure generator constituted by a gravity-feed bottle, a flow generator which is constituted by a syringe. In addition, this flow generator, contrary to the pressure generator, allows intra-arterial injections and a better control of subcutaneous and intradermic perfusions, i.e. in situations where the counter-pressure developed at the site of injection is high and uncontrollable.

Numerous automatized syringe-driver devices have been proposed, such as those of British Patent Application No. 77/09947, U.S. Patent 3 858 581, 82/355102. The devices shown in these references comprise a piston-driver mechanism composed of a motor, an endless screw rotating on bearings, and a carriage disengageable from the endless screw allowing manual 3 rearward return. The endless screw and the carriage are totally or partially visible. The casing comprises a means for securely containing the syringe. Control of the flowrate was obtained in the earliest embodiments by controlling the angular speed of the motor.

More recently, and in order to extend the range of flowrates available, a discontinuous functioning of the motor has been preferred, the mean angular speed thereof being variable from 1 to 100. In general, this result is obtained by a D.C. motor whose rotation is initiated by a clock and terminated by a cam mechanically secured to the endless screw and acting directly on a contactor. Insofar as the duration of the pauses between injections are short having regard to the half-life of the drug injected, the variations in systemic concentration of the drug will be negligible.

The total duration of emptying the syringe is a variable which depends on the nominal volume of the syringe, the desired mean flowrate and the titer of active product in the solution injected.

summary of the Invention In the present invention, the entire electromechanical system for advancing the piston is located inside a guide-envelope which serves as a support means for two lateral faces of a casing which contain the syringe, without additional containing means. The advantage of this technique resides in the considerable compactness and miniaturization of the device. The mean flowrate is obtained by the delivery of a fixed number of volumes or boluses injected at each period during a predetermined total duration.

Description of the Drawing Fig. 1 is a view, in perspective, of a device i: %h t 4 according to this invention on which is mounted a syringe; Fig. 2 is a view of the device shown in Fig.

1, also in perspective, but partly broken away and with the device rotated 180' from the position shown in Fig. 1; Fig. 3 is a side view of a further embodiment of the invention; Fig. 3A is a partial end view of the device shown in Fig. 3; Fig. 4 is a side view of an electro-mechanical mechanism contained within the device shown in Fig. 2, the side wall of the device being removed to expose the mechanism; Fig. 5 is a schematic diagram of a control circuit for the mechanism shown in Fig. 4; Fig. 6 is a schematic diagram of a control circuit for an electro-mechanical system contained within the device shown in Fig. 3; and Fig. 7 is a schematic diagram of a circuit for monitoring the state of discharge of the batteries used in devices according to this invention, Detailed Description of the Invention By way of non-limiting example, we shall describe a syringe-driver device with constant unitary volumes, programmed by clock, particularly intended for the maintenance of intravenous catheters during ambulatory treatment.

The devices are composed of a syringe-driver mechanism proper and of an electronic programmable assembly with a power supply independent of the mains.

The syringe-driver device shown in Fig. 4 is composed of a geared motor advantageously constituted by a D.C. motor without iron rotating with energization k 35 by permanent magnet of low inertia, and of a reduction

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S- 5 -5 gear with high yield and a coaxial driven shaft on i which is directly fixed an endless screw by a rigid bushing. The geared motor is fixed at its front end by means of an elastic material which enables it as well as the endless screw to float lightly inside a guide-envelope in order to overcome the inevitable defects in alignment of the assembly, the endless screw i being free of any bearing. The endless screw (3) screws and unscrews in a threaded carriage bearing a S 10 piston-driver stud and a magnet acting on switches and/or inverters outside the guide-envelope The endless screw bears in addition a rotary magnet which acts on another switch (10) sensitive to the magnetism and outside the guide-envelope Guiding of the carriage is effected by the envelope itself which is to that end a profile of polyhedral section homologous to that of the carriage The upper face of the guide-envelope includes a slot intended for the passage of the piston-driver stud A slitted elastic curtain (11) (see, also, Fig. 2) protects the endless screw and its carriage against the entry of dirt and the like into the guide-envelope The curtain (11) may advantageously be made of a water-proofed fibrous material, for example, a textile felt, secured to a small plate (13) screwed to the guide-envelope The lower face of the guide-envelope constitutes a support and a protection for an electronic assembly described hereinafter and for the supply battery.

A box-like casing (Fig. 1 and Fig. 2) for the device is disposed around the guide-envelope which provides reinforcement thereof.

This casing has the form of a rectangular parallelepiped, both internally .nd externally. Its upper face is directly formed by the upper face of the guide-envelope Its rear face (26) is removable and bears alone the controls (14) and displays (15) of the I r 6 apparatus. Its lateral faces are extended above the guide-envelope by expansions (16 and 17) over the whole length of the casing, Adequately formed, the expansions (16) constitute a syringe-holder grip of arcuate section in the front part of the apparatus. The expansions (17) comprise a pair of parallel walls and serve to partly enclose and protect the piston of the syringe (19).

Two bands (18) parallel to the casing and screwed to the wall of the casing reinforce the whole and improve the elasticity and the solidity of the syringe-holder grip. In this way is obtained a particularly light and compact casing which may be made by simple and inexpensive means and in which the introduction of the guide-envelope and its contents, the electronic control means, and the rear-holder (26) aSsembly is particularly easy and rapid.

The inventive apparatus, by its simple geometrical form and the excellent protection of the syringe (19) provided by the expansions (16) and (17) of the casing and the protection of the piston driving mechanism provided by the guide-envelope is particularly suitable for ambulatory treatment, for example, being carried in a patient's garment pocket or fixed by a mini-harness to the patient.

Two principal modes of operation of the inventive devices are now described, One such mode, which uses the device shown in Figs. 1 and 2, is particularly intended for maintaining the permeability of intravascular catheters and/or for the injection of medicaments.

In this mode of operation, the following functions, by way of example, are performable: forward operation of the syringe piston, stroke by stroke, separated by periods of relaxation, rapid forward operation and initialization, and rapid, irrevocable rearward return controlled either manually or 'i; 7 automatically in the event of excessive prolongation of the duration of the active period.

These different functions are provided, respectively, by the motor driving circuit (Fig. 5) as follows: For forward operation stroke by stroke, a clock capacitor (51) is charged at a constant rate through a transistor (QI) functioning, in association with a constant voltage dropping Zener diode as a constant current source. One electrode of the capacitor (51) is connected to the anode of an anode gated thyristor the gate of which is connected to one electrode of the Zener diode hence held at a constant voltage. When the charging of the clock capacitor (51) reaches a level where the voltage thereacross exceeds the turn-on voltage of the thyristor (Ti) an anode voltage slightly in excess of the gate voltage), the thyristor (Ti) turns on thereby providing a path for discharge of the capacitor This discharge current, passing through a resistor (54), causes a voltage spike which is applied, via a diode (DI) to the gate electrode of a thyristor (31), thereby turning it on.

When the clock capacitor (51) discharges through the thyristor the voltage at the thyristor anode drops below the voltage at the gate and the thyristor (TI) turns off. This allows the beginning of the recharging of the capacitor The clock capacitor (51) and its associated circuit elements thus comprise a relaxation oscillator (29) where the rate of oscillation, the frequency of the output voltage spikes (across resistor is a function of the linear charging rate of the capacitor Because, as hereinafter described, the output voltage spike causes a momentary activation of the motor the period between the output voltage spikes controls the relaxation time between forward strokes of the syringe 8 piston (21).

Returning to the thyristor when it is turned on, in response to a voltage spike from the relaxation oscillator current is applied, via a photo diode to the base electrodes of two complementary transistors (Q2) and The transistor (Q2) is thus turned on, and current is applied to the motor to cause rotation of the endless screw (3) (Fig. 4) attached thereto. This causes a forward stroke of the syringe piston.

Stopping of the motor is obtained by the closure of a disruptive switch (10) sensitive to the rotary magnet through the guide-envelope such closure causing turn-off of the thyristor (31) by shortcircuiting the thyristor anode to its cathode. Although the thyristor (31) is thus turned off, current to the motor continues to flow via the closed switch until the further rotation of the magnet relative to the switch (10) causes a re-opening of the switch. This eliminates the current supply to the base of the transistor (Q2) thereby turning it off and stopping rotation of the motor. Any back EMF generated by the armature of the motor is short circuited through the transistor (Q3) to ground, thereby rapidly stopping the motor.

For rapid forward driving of the syringe piston, to arrive at an initial position from which, for example, a stroke by stroke operation follows, a manually operated driver switch (14) is closed for applying a continuous source of current to the motor This causes continuous rotation of the motor independently of the opening and closing of the switch A variant of this function may be obtained by a manually operated switch, not shown, which considerably increases the charging current of the clock capacitor (51) of the principal relaxer (29).

~For rearward return of the carriage an 3 9 inverter relay (IR) is energized either manually, by means of a switch or with the aid of an auxiliary relaxation oscillator The inverter relay (IR) controls relay contacts (62) and and when the relay is energized, the contacts flip from the positions shown in Fig, 5 to the positions indicated by the arrows. When the relay is de-energized, the contacts flip to their original positions.

Flipping of the relay contact (62) from the position shown in Fig. 5 thus connects the positive terminal of the battery to lad which is connected to the motor via a resistor The motor is thus driven in the reverse direction by current flow through the resistor the motor, and the transistor (Q3) to ground.

As shown in Fig. 5, a lead (L3) short circuits a horn During forward driving of the motor, which is the situation illustrated in Fig. 5, current passing through the motor is shunted around the horn by the lead and the horn does not sound. However, upon operation of the inverter relay (IR) and the flipping of the relay contact the lead (L3) i disconnected i from the horn and connected instead to lead This accomplishes two things, one is that the horn is not short circuited by the lead and current from the battery, via relay contact (62) and lead passes through the horn to cause sounding t',ereof.

The other thing accomplished is that the flipped contact (64) provides a continuous circuit from the battery through the inverter to around, Thus, when the manually operated switch (60) is released the relay remains energized to complete the full reverse travel of th' carriage Turn off of the relay is described hereinafter.

The operation of the relaxation oscillator (30) is similar to that of the oscillator Thus, a V.y

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10 clock-capacitor (70) has one electrode connected to the anode of an anode gated thyristor (T2) which, when turned on by the capacitor developes a voltage spike across a resistor (72) to turn on a thyristor (74) to energize the inverter relay (Once turned on, the thyristor (74) stays on until open-circuited, as hereinafter described.) Charging of the capacitor (70) occurs during those times when the thyristor (31) of the relaxation oscillator (29) is on, or when the switch (10) is closed, the charging path being from the positive terminal of the battery through the thyristor (31) or switch the photo diode the resistor (76), the lead and the resistor (78).

The rate of charging of the capacitor (70) is selected so a' to exceed the normal on time of the thyristor (31) (including the time of closure of the switch so that during the normal stroke by stroke mode of operation, the charge on the capacitor never reahes a level sufficient to operate the relaxation oscillator. During the relaxation time between strokes, when the thyristor (31) is off, the capacitor (70) discharges through the resistors and (55) so no accumulation of charge occurs during normal stroke-by-stroke operation.

converselyv, if the forward advance of the syringe piston is excessively resisted, resulting, for example, from an excessive pressure within the syringe caused by blockage of flow from the syringe, the rate of rotation of the screw is reduced or stopped, the magnet is slow reaching the angular position to activate the motor turn off switch and the thyristcr (31) remains on an excessively long time.

This allows charging of the capacitor (70) to the level necessary to turn on the thyristor (T2) to energize the inverter relay This, in turn, causes, as described, driving of the motor in the reverse Wi 11 direction.

The foregoing described function replaces at the same time a device for detection of racing by accidental elimination of the relaxations and the end of forward stroke. The end of rearward stroke is ensured by a normally closed switch (20) (Figs. 4 and sensitive to the magnetic field of the magnet the opening of the switch in response to the arrival of the magnet serving to remove power from the system and to allow the various relay contacts to revert to the positions shown in Fig. 5, The system is thus ready for a new sequence of operations.

Determination of the maximum force exerted by the assembly comprising the geared motor endless screw carriage and paston-driver stud on the piston (21) of the syringe (19) is obtained by means of control of the current through the geared motor (2- Adjustment of the current to a maximum value chosen as corresponding to an excessive pressure is en&ured approximately by a ballast resistor (68) in series with the geared motor and completed by a fine adjustment of a resistor (76) limiting the base current of the transistors mounted in common emitter which supply the geared motor.

In a version more especially intended for iterative intradermic injections, the casing takes the form of a pistol (Fig. 3) in the stock of which is housed the battery which is accessible through a cover plate The rest of the casing has the parallelipipedic form already describad and comprises in particular the sam zeans of fixation and protection of the syringe.

With the pistol form, a stroke by stroke forward operation, a rapid advance and an automa

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Irrevocable rearward return are also possible.

These different functions are obtairne respectively (Fig. 6): 12 4 f "4Z For stroke by stroke operation, a capacitor charged directly from the battery, is connected by a switch (82) (the "trigger" of the pistol grip shown in Fig. 3) to a thyristor (84) for turning it on. The turned on thyristor (84) causes rotation and subsequent stoppage of the motor in the same manner as describeC in connection with Fig. For rapid forward operation, a manually operated switch 14' is provided for the direct supply of i0 the bases of the two complementary transistors Q2 and Q3.

For rearward return, a normally open switch (22) (see, also, Fig. 4) is provided adjacent to.the guide envelope at the forward end-of-stroke position of the carriage the switch (22) being closed in resonse to the magnetic field from the magnet (8) carried by the carriage. The closing of the switch (22) (Fig. 6) energizes the inverter relay (IR) which causes, as described in connection with Fig. 5, the rearward movement of the carriage. Also, as described in connection with Fig. 5, the flipping of the relay contact (90) and (92) (Fig. 6) provides a current path through the inverter relay after the switch (22) is reopened by rearward movement of the carriage.

The only display is constituted by an electroluminescent diode (15) visible through a transparent stopper (24) (Fig. 3) located at the front of the guide envelope and which is supplied when the thyristor (84) (Fig. 6) or the switch (10) (actuated by the rotary magnet are conductive.

The permanent emission nf light from diode thus indicates that the geared motor is live but hindered by an excessive reaction of the piston (21) of the syringe (19) translating an obstacle to the flow 3$ of tfuid contained therein.

The transparent stopper (24) advantageously bears a threaded blind hole in which rotates a screw i 13 with knurled cylindrical head which serves as a stop to adjust the penetration of the needle (23) into the patient's dermis. The head of this screw (25) in contact with the patient's skin may be capped by singleuse cups.

In one variation, the switches and/or inverters used for determining the forward and rearward ends-of-stroke may be replaced by a reversible counter counting the positive and negative turns of the endless screw with the result that the number stored in the reversible counter is representative of the position of the carriage between the ends-of-stroke. This embodiment presents the advantage of being able easily to vary the position of the ends-of-stroke and, on doing so, of adapting the stroke of the carriage to the stroke of the piston of the syringe.

When the electrical supply is provided by a cadmium-nickel accumulator battery, the rear door (26) (Fig. 3A) may advantageously be provided with a socket (27) which, connected to a charger itself connected to the mains, allows rechargirng of the accumulator battery without dismantling or removing the cover plate (28).

In order to monitor the state of discharge of th( battery, an accessory device (Fig. 7) may advantageously be made, comprising an electroluminescent diode, a micro-relaxer, a Zener diode and a shunt resistor.

The accessory device may either be integrated in the casing, or in the charger (in that case it is completed by a switch), or it may be made separately and consulted after p3ugging in the socket (27) for charging the battery.

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Claims (17)

1. An electro-mechanical single stroke syringe driver comprising: a longitudinal casing of polyhedral cross section, substantially closed and having a longitudinal slit extending along an upper face thereof; an electro-mechanical driver located within the j casing, the electro-mechanical driver comprised of: i) an electric motor; j ii) a longitudinally extending threaded rod attached at one end thereof to said motor and for rotation thereby; iii) a carriage of homologous section to that of the casing mounted on said rod and having a complementary thread whereby rotation of said rod causes longitudinal movement of said carriage between a starting position and a finishing position, said carriage including a portion extending through said slit for engagement with a syringe piston; i a longitudinally extending syringe holder of trapezoidal section, the base of which is constituted by the upper face of the casing and the sides of which are urged together by bands extending longitudinally therewith; electrical control circuits, an.; at least one rechargeable battery having a recharging terminal accessible from outside the casing for recharging the at least one battery without dismantling of the driver, wherein: -14- 0C~ S r 0391k/SC the threaded rod is without additional bearings and that rotation of the rod is controlled by a bipolar magnet rotating with said rod acting on a magnetically sensitive switch; the pressure of fluid within the syringe is controlled by measuring the electric current passing through the motor armature, and; return of the carriage to the starting position results in all control circuits being disabled except a circuit for initiation of forward operation.

2. A device as claimed in claim 1 wherein a signal for initiation of rotation of the motor corresponding to delivery of a predetermined dose is provided by a capacitor charged by a constant current which delivers an impluse to a thyristor connected to two complementary transistors connected in a common emitter configuration supplying the motor.

3. The device of claim 1 wherein rotation of the rod corresponding to delivery of a predetermined dose is determined by optical or ultra-sonic means cooperating with said rod.

4. The device of any one of the preceding claims further including a reversible analogue or numeric counter for counting positive and negative rotation of the rod and providing a readout indicative of the position of the carriage. 15 i p391k/SC

5. The device of claim 4 wherein the finishing position of the carriage corresponds to the zero position of the counter.

6. The device of any one of preceding claims 2 to 5 wherein the pulse for controlling the thyristor is furnished by a programmer.

7. The device of claim 6 wherein the programmer is a clock.

8. The device of claim 7 wherein the programmer is servo-controlled by an outside measure provided as an electrical signal.

9. The device of claim 8 wherein the outside measure is that of the plasmatic concentration of glucose of the user.

The device of claim 2 wherein when the current through the motor armature exceeds a predetermined limit, the direction of rotation of the motor is reversed.

11. The device of clai 10 wherein reversal of the motor rotation is accompanied by a sound or light signal.

12. The device of any one of the preceding claims wherein an alarm sounds when the carriage is a predetermined distance from its finishing position. I 16 j ,0391k/SC

13. The device of any one of the preceding claims wherein return of the carriage to the starting position is obtained by reversal of the polarities of the motor by means of a double j inverter controlled by the current in the motor armature, or by a manual switch, said inverter returned to a forward operation position by means of a switch operated when the carriage is at Kj the starting position.

14. The device of any one of the precediig claims characterised in that the electrical supply is at least one Nickel-Cadmium battery.

The device of any one of the preceding claims wherein an optical alarm is provided when the battery is low in stored energy.

16. An electro-mechanical syringe driver, substantially as herein described with reference to the drawings. DATED this 21st day of September, 1990. HAZON BERNARD, ANDRE SAUSSE By Their Patent Attorneys ARTHUR S. CAVE CO. A' i

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