GB2503275A

GB2503275A - Electrically powered portable syringe

Info

Publication number: GB2503275A
Application number: GB1211050.8A
Authority: GB
Inventors: John Setchell
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-06-21
Filing date: 2012-06-21
Publication date: 2013-12-25
Also published as: GB201211050D0

Abstract

A syringe which is portable and hand held, has self contained power actuation by means of trigger 30 activating power supply or battery 29, is repeatedly refilled via inlet 11 and upon activation delivers or injects a selected volume of fluid from chamber 6 through outlet 9. The piston 5 has an open space which is filled as the injection takes place, and as piston 5 is withdrawn to the ready position fluid moves from said space to chamber 6 through a one-way valve. The dosage may be adjusted via potentiometer 32. The electrical motor 1 may have a gearbox 2 and moving shaft 4. This syringe may be used to dose livestock.

Description

An Electrically Powered PpbJe Swjnge

Field of the Invention

The Invention relates to a hand held portable power actuated self filling syringe preferably intended for drench vaccination of livestock.

Background to the Invention and Prior Art known to the Anulicant The closest prior art document known at the time of filing of this application is US Patent 5,269,762 dated 14 December 1993, which discloses a hand held battery powered device to drive a syringe for hypodermic injection of fluids into humans during operating theatre procedures. A syringe filled with fluid may be installed in the device, which under control of a trigger-shaped switch drives the plunger within *the syringe displacing the fluid which travels along a tube to the hypodermic needle and into the patient The syringe is not automatically refilled as the intention is that it is used only once. The disclosure specifically eliminates the use of electronic control of the device as being too expensive and unreliable at that time, the operation being electro-mechanicaf One of the objects of the Invention is to reduce physical stress of those drench vaccinating maybe hundreds of livestock, which may be agitated, possibly in conditions of poor weather or light. Such vaccination requires placing a specific dose of liquid in the animal's throat via its mouth. This is generally currently achieved using a hand operated syringe, squeezing the handle of which pushes the plunger within the syringe forward, ejecting fluid via a delivery nozzle placed in the animal's mouth. To facilitate repeated treatments the syringe is self filling via a flexible tube from a back-pack bottle worn by the Operator. The handle of the syringe is spring-loaded to drive the piston back for automatic refilling.

The manual strength and dexterity required to perform this operation against spring pressure and hydraulic resistance when treating numerous animals can be very testing, and may contribute in the long term to Repetitive Strain Injury.

Useful advances in vaccine development, and increasing responsibility for Animal Welfare are requiring more frequent and widespread drench vaccination of livestock.

Summary of the Invention

In its broadest independent aspect, the Invention provides a portable selfpowered automatically refilling syringe for repeatedly administering a variable specific dose of vaccine orally to livestock The vaccine fluid is carried in a back-pack bottle by the Operator, and is drawn into a syringe via a flexible tube during powered operation of the syringe. During the delivery stroke of the syringe piston a. specific volume of fluid is ejected via a fixed or flexible tube into the animal's mouth, and an equal amount of fluid is drawn in behind the syringe piston from the back-pack in readiness for the next dose. This arrangement of fluid both upstream and downstream of the piston allows the inlet port to which the flexible tube is connected to be in a fixed position on the syringe, and not inconveniently move with the piston shaft presenting possible trap-hazard.

A pair of non-return valves in the syringe ensure that fluid passes along the hydraulic path direction from back-pack to animal during the delivery stroke.

When the specified dose has been delivered the syringe piston automatically stops and returns to its starting position, a valve in the piston opening under hydraulic pressure to allow the next dose of fluid to pass downstream through it as the piston returns. The spring-loaded second non-return valve closes ensures that fluid does not return back along the hydraulic path to the back-pack bottle.

In a subsidiary aspect the above dosing cycle is initiated by the Operator squeezing a trigger-switch on the handle of the device. This may be a "fire and forget" process which does not require monitoring or continued squeezing of the triggerduring the cycle. The process may be automatically disarmed for a set time of perhaps S seconds following the delivery cycle to prevent accidental double-dosing to an animal.

This arrangement minimizes the physical input necessary by the Operator to administer drench vaccination, and allows him or her to give full concentration to Health and Welfare of the animal and the Operator.

In a further subsidiary aspect the trigger-switch squeezed by the Operator instructs electronic control circuitry to draw electrical current frOm a removable and rechargeable battery within the handle of the device to drive a reversible direct current motor. This motor drives an integral gearbox which in turn rotates an integral captive screw. The screw rotates inside a threaded drive shaft, as a reaction to which the shaft moves forwards driving the attached syringe piston during the delivery stroke. As the shaft moves forwards it carries the sliding connection (tap) of an adjacent linear potentiometer, voltage values from which are used by the electronic control circuitry to sense the piston at-rest and full-dose positions. When the full-dose position is sensed the electronic control circuitry automatically reverses the polarity of electrical voltage to the motor, which consequently goes into reverse and returns the piston to the sensed at-rest position.

In a further subsidiary aspect the Operator may set the delivery dose volume by pressing and turning a knob on the device. Pressing the knob engages a non-latching switch which instructs the electronic control circuitry to allow the knob to take control of the motor and thus the syringe piston position. Turning the knob then adjusts a potentiometer which advises the electronic control circuitry to drive the motor and thus piston backwards or forwards to a position chosen by the Operator, gauged against volume calibration markings along the syringe cylinder wall by turning the knob. The potentiometer attached to the knob has a logarithmic scale to allow setting of critical small doses most accurately. Releasing the knob disengages the switch, which instructs the electronic control circuitry to read the voltage value of the linear potentiometer adjacent to the chosen shaft position and use it as the new dosing stroke limit.

In a further subsidiary aspect the motor, gearbox, shaft.housing, and all electronic circuitry are housed in a dirt and splash proof non-shattering plastic housing which has no sharp edges and is integral with handle and rubber-blister covered trigger switch. This provides a robust physical construction for outdoor use, and minimizes injury hazards to the animal or Operator. The housing incorporates a handle for single handed operation of the device, located beneath centre of gravity of the device to minimize effort required to align the delivery nozzle during operation.

Brief Description of the Figures

Figure 1 shows a section through the device, indicating position of elements within the housing.

Figure 2 shows details of the syringe in section shown in figure 1, and axial views of the two non-return valves.

Figure 3 shows a schematic of the electronic control circuitry.

Detailed description of the Figures

Figure 1 shows the device generally referenced with housing (3), cylinder of syringe (6) and delivery nozzle (9).

The electrical motor (1) may be integral with gearbox (2j. shaft encasement (3), and moving shaft (4). These four items are commonly collectively known as a Linear Actuator. They convert stored electrical energy from the battery (29) to linear movement of the shaft (4). The rechargeable battery (29) may be removable to provide duty & spare, and may be rated at 12 volt to allow convenient recharging from vehicle cigarette lighter socket whilst providing maximum available power.

The syringe piston (5) is attached to end of the shaft (4) and travels with it forward to provide dosing, and backwards to refill volume downstream of the piston.

Vaccination fluid enters the syringe via inlet port (6) over which is ptaced a flexible tube from the Operator's back-pack. Fluid is then drawn into the syringe cylinder (6) as the piston (5) is pushed forwards by the shaft (4J During this dosing stroke fluid downstream of the piston exists through the one-way valve (8) which is opened by hydraulic pressure, and through the delivery nozzle (9) to the animal.

The nozzle shown in figure 1 is that used for drench vaccinating small stock such as lambs) but other nozzles may be used such as hook nozzle or nozzles on flexible tube to suit the livestock being treated and conditions. The nozzle may be changed and * non-return valve (8) cleaned or repaired by removing screwed securing collar (10).

Plastic housing (34) provides physical location and protection for the electronic elements and Linear Actuator assembly. Rechargeable battery (29) may be removed from the housing via a detachable cover at base of the handle.

Trigger-switch (30) is pressed by the Operator and initiates the automatic dosing and refilling cycle, and is electrically connected to the electronic circuit board (27), which in turn is connected to the electric motor (27) to rotate forwards or backwards as required. Linear potentiometer (28) senses the position of the shaft (4) sending values to the electronic control board (27). Dose setting knob (33) may be depressed by the Operator to close switch (32) and turned to adjust potentiometer (31) both of which are used by the electronic control board to move the piston (5) to required dose volume as indicated by calibration marking on the syringe cylinder (6).

Figure 2 shows the syringe in detail, with axial elevation view of the two non-return valves.

Collar (7) provides physical connection between the syringe cylinder (6) and static case of the travelling shaft (3). It may be secured to the shaft case with screws (12) and to the syringe cylinder which screws into it with "0" ring seal (14). Collar (7) also houses "0" ring seal around the travelling shaft (13) and accommodates inlet port (11) screwed into it.

The syringe piston (5) is secured to end of the travelling shaft with screw (24) through spacer-washer (25), which with shaft-end chamfer (26) allows fluid flow to holes in the piston (22). During the dosing stroke hydraulic pressure holds flexible diaphragm (23) against the piston disc (5) which together with "0" ring seal (21) forces fluid downstream. This pressure against the poppet valve (8) compresses spring (17) and moves the "0" ring seal (18) away from its tapered seat (19) in body of the valve (15). "0" ring seal (16) retains hydraulic pressure atthe push-fit of valve body (15) into reduced diameter end of the syringe cylinder (6).

Collar at head of nozzle (9) allows the valve poppet to travel downstream when open, whilst retaining end of spring (17). "0" ring seal (20) maintains hydraulic pressure where nozzle collar is a push-fit into valve body (15). Retaining collar (10) screws to base of reduced diameter syringe cylinder (6), securing nozzle (9) in place.

Figure 3 shows a schematic of the electrical control system for powered operation of the syringe.

Removable rechargeable battery (29) provides preferred voltage of 12 volts to power the circuits. It is connected to electronic control board (27) which receives electrical information from switches and potentiometers, and is programmed to operate the direct current electrical motor (1).

Sliding tap of linear potentiometer (28) is moved by the shaft (4) as it travels backwards and forwards, thus the voltage value from it allows the electronic control board to read where the shaft is in its cycle.

Trigger-switch (30) is pressed by the Operator and sends a signal to the electronic circuit board which initiated the cycle.

Non-latching press switch (31) and logarithmic potentiometer (32) are used by the Operator to set the extent of shaft travel and thus dosage volume. Switch (31) instructs the electronic circuitry to allow voltage from potentiometer (32) temporary priority to drive the motor backwards or forwards to locate the piston in a position of the Operator's choosing for dose volume. Release of switch (31) signals the electronic control circuitry to read voltage from potentiometer (28) and use it as a referencefor the new end of travel for the dosing stroke.

Claims

Claims 1) A syringe which, in use, is portable and hand held, and has self contained power actuation; a syringe which repeatedly refills and delivers or injects a selected volume of fluid; the effort of operation of the said syringe being provided by an electrically driven motor, gears, and screwed shaft.
2) A syringe according to Claim 1) into which the fluid is continuously admitted through a dedicated fixed position inlet port.
3) A syringe according to Claims 1) and 2) wherein fluid is admitted to the syringe simultaneously with delivery of the preceding dose.
4) A syringe according to any of the preceding claims, wherein electrical motor providing motion of the piston is controlled in direction and length of stroke by electronic circuitry referring to switches and or potentiometers operated by the syringe Operator and or the travelling shaft.
5) A syringe according to any of the preceding claims, wherein the Operator may set the volume of fluid to be dispensed using switch and potentiometer to control the electronic control circuitry to position the syringe piston, this position thereafter being the electronic reference for future doses until amended by the Operator.