NZ248879A - One-piece one way valve made of resilient plastics material - Google Patents

Description

Patents Form #5 2*8879 8 SEP 1994 '} v NEW ZEALAND Patent* Act 1953 rOMPT.FTF. SPF.fTFFIf? ATTON TITLE: Valve We, Simcro Tech limited Address: 23 Bandon Street, Hamilton, New Zealand Nationality: New Zealand hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: PF05JWP FEE CODE-1050 248879 This invention relates to valves of the kind usable in positive displacement liquid pumps and particularly to valves suited to use in vaccinators, drench guns 5 or the like for administering a predetermined volume of liquid to an animal either internally or externally.

According to one aspect of the invention, there is provided a valve to allow passage of liquid therethrough in one direction but to inhibit flow of said liquid 10 therethrough in the opposite direction, the valve including a static element, a mobile sealing element and spring means to bias the mobile element relative to the static element and in which the static and mobile elements and the spring means are formed as an integral body of the same material, in which the mobile sealing element includes a substantially cylindrical skirt portion having a free 15 end to bear against and thereby seal against a surface of a body to which the valve is adapted to be fitted, the sealing element including an integral blanking portion from which the skirt portion protrudes, so as to close the skirt portion, and in which a guide member extends from the blanking portion, the guide member being adapted to allow the liquid to pass it and to be a sliding fit in a 20 co-axial bore of said body to which the valve is adapted to the fitted, whereby to retain said free end of the skirt portion generally in a plane normal to said bore.

Preferably said valve is formed as a moulding of a resilient plastics material.

According to another aspect of the invention, there is provided a valve in which the static element is an integral part of a piston, co-axial therewith.

One embodiment of the invention is described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is a side view of a drench gun, incorporating two valves according to the invention, Figure 2 is a section along the line II - II in Figure 1.

Figures 3,4 and 5 are perspective views at enlarged scale of three 6886MMIS. 49'6/bs/ns & ^ ^ A 248879 shown in Figure 2.

Figure 6 shows part of Figure 2 at enlarged scale, and Figure 7 shows another part of Figure 2, at enlarged scale.

Figure 8 shows an alternative embodiment to that shown in Figure 4, and Figure 9 shows an alternative to Figure 5.

In the drawings, a drench gun, includes a handle 10 to the bottom of which is pivoted the bottom of a trigger member 11. The upper end of the handle 10 is integral with a substantially cylindrical body 12 from which protrudes a coaxial transparent chamber 13. A nozzle 14 is fastened coaxially on the end of the chamber 13 remote from the body 12, conveniently by a threaded connection.

An outlet valve 15, shown particularly in Figures 4 and 6 comprises an integrally formed plastics moulding having an annular flange 16 trapped between a shoulder on the nozzle 14 and the end of the chamber 13.

As shown in Figures 4 and 6, a first cylindrical portion 17 extends from the flange 16, and is a close fit in a bore 23 of the chamber 13, whereby the cutlet valve 15 is radially located therein. A pair of curved diametrically disposed arms 18 carry a second cylindrical portion 19 closed by a diaphragm 20 adjacent the arms 18. A cruciform or three-lobed section locator 21 extends from the diaphragm 20 and is a sliding fit in a coaxial bore 22 in the outlet of the chamber 13. The internal surface of the chamber 13 between the bores 22, 23 includes a conical portion 24, against which the free end of the second cylindrical portion 19 of the outlet valve 15 is urged by the arms 18, which also act as springs. Thereby, the free end of the second cylindrical portion 19 is sealed against the conical portion 24.

When the pressure within the chamber 13 becomes less than the pressure within the nozzle 14 the sealing of the second cylindrical portion 19 to the conical portion 24 inhibits the flow of any liquid or air from the nozzjynta the% 6886HAKS. 496/bs/us ~6 loss 248879 chamber 13. However, as the pressure within the chamber 13 is raised, the consequent axial force on the diaphragm 20 becomes greater than the axial force exerted by the arms 18, so that the latter flex, allowing the second cylindrical portion 19 to move axially from the conical portion 24, whereby the contents of the chamber 13 can be discharged through the nozzle 14.

As shown particularly in Figure 7 the right hand end of the body 12 carries an externally ribbed dose adjustment member 25 which can be rotated on the body 12 to a plurality of predetermined angular positions. The centre of the member 25 is formed as a bearing 26 in which a hollow piston rod 27 is slidable. The right hand end of the piston rod 27 is formed as a hose connection 28. The piston rod 27 is connected to the upper end of the trigger member 11, whereby movement of the trigger member 11 relative to the handle 10 moves the piston rod 27 in and out of the body 12.

The left hand end of the piston rod 27 has affixed thereto a combined piston 29 and inlet valve 30, all formed as a single integral plastics moulding. The piston 29 comprises a spigot 31 fastened on the outside of the piston rod 27 and a pair of discs 32 which are a sliding fit in the bore 33 of the chamber 13. Each disc 32 is formed with an outwardly directed resilient sealing lip 34, bearing and sealing against the bore 33 of the chamber 13. The spigot 31 also carries a pair of arms 35, which act in a manner analogous to the arms 18 and carry the inlet valve 30. The latter is identical in construction to the outlet valve 15, being a sliding fit in the bore 36 of the piston rod 27 and having a resilient third cylindrical portion 37 urged by the arms 35 into sealing engagement with a conical surface 38 extending from the bore 36. The outlet valve 15 may be smaller than the inlet valve 30.

When the piston rod 27 is moved to the left, the rise in fluid pressure in the chamber 13 urges the third cylindrical portion 37 to move firmly against the conical surface 38. Conversely, when the piston rod 27 is moved to the right the reduced pressure in the chamber 13 causes the inlet valve 30 to open, whereby liquid can be drawn into the chamber 13 through the piston rod 27.

Figures 8 and 9 show valves very similar to those shown in Figure ^&nd 5(. :.;v 6B86MM«S.496/b»/m» ; *" 24 8 8 However, the springy arms 18, 35 are replaced by integral C-shaped springy arms 50, 51 respectively. The arms 50 in Figure 8 lie substantially in a plane normal to the axis of the valve 15 and each arm 50 is mounted on a pillar 52, integral with and extending forwardly from the cylindrical portion 17.

Similarly in Figure 9, the arms 51 are each mounted on a pillar 53 integral with and extending forwardly from the valve 30.

Where the nozzle 14 is threaded onto the end of the chamber 13, the flange 16 preferably is formed with several parallel ribs 55 engaged in mating grooves in the end of the chamber 13, to inhibit wringing of the outlet valve 15 on assembly. Some shorter, thicker, intermediate ribs 56 maintain a gap between the flange 16 and the end of the chamber 13, to assist easy removal of the valve 15, when required.

The valves 15, 30 and piston 29 are preferably made of a suitable plastics material having an adequate degree of resilience and a good memory, such as acetal, nylon, polypropylene or a thermoplastic rubber. More than two of the arms 18, 35 may be used, if required.

Although the invention has been described with reference to drench guns, it is equally applicable to valves for use in vaccinators, particularly those in which the vaccine is drawn into one end of the vaccinator and displaced through a hollow needle from the other end of the vaccinator.

Finally, it will be appreciated that various alterations or modifications may be made to the foregoing without departing from the spirit or scope of this invention. 6&&6MAMS. 496/bs/ms 2 4 8 8 7

Claims (14)

WHAT WE CLAIM IS:

1. A valve to allow passage of liquid therethrough in one direction but to inhibit flow of said liquid therethrough in the opposite direction, the valve including a static element, a mobile sealing element and spring means to bias the mobile element relative to the static element and in which the static and mobile elements and the spring means are formed as an integral body of the same material, in which the mobile sealing element includes a substantially cylindrical skirt portion having a free end to bear against and thereby seal against a surface of a body to which the valve is adapted to be fitted, the sealing element including an integral blanking portion from which the skirt portion protrudes, so as to close the skirt portion, and in which a guide member extends from the blanking portion, the guide member being adapted to allow the liquid to pass it and to be a sliding fit in a bore of said body to which the valve is adapted to be fitted, whereby to retain said free end of the skirt portion generally in a plane normal to said bore.

2. A valve according to claim 1, in which the guide member comprises three or more radial blades.

3. A valve, according to claim 2, in which cross sections of the guide member in planes parallel to the plane of said free end are symmetrical radial crosses.

4. A valve according to any preceding claim in which said static element is formed with a radial flange, to be trapped and thereby sealed between two relatively axially movable components.

5. A valve according to claim 4, in which said flange or said static element is formed with a feature adapted to engage a matching feature on one of said components, to inhibit relative rotation between the valve and said one component during fitting of the valve. 248879 -7-

6. A valve according to claim 5, in which the feature comprises one or more parallel ribs adapted to engage in matching grooves in said one component.

7. A valve according to any of claim, 4 or 5 in which said flange bears one or more integral spacers, to prevent one face of the flange abutting an end of said one component.

8. A valve according to any of claims 1 to 3 in which the static element is an integral part of a piston, co-axial therewith.

9. A valve, according to claim 8, in which the piston and the valve are formed as a one-piece moulding of a resilient plastics material.

10. A valve, according to any preceding claim, in which said spring means includes a curved member attached at one end to said static element and at the other end thereof to said mobile element.

11. A valve, according to claim 10, in which the curved member lies substantially in a plane which includes the longitudinal axis of the valve.

12. A valve, according to claim 10, in which the curved member is a generally C-shaped member and lies in a plane substantially normal to the longitudinal axis of the valve.

13. A valve, according to claim 10, 11 or 12 in which there are two or more of said curved members spaced evenly apart.

14. A valve constructed and arranged and adapted to operate substantially as described herein and as shown in the accompanying drawings. JAMES W PIPER & CO Attorneys for SIMCRO TECH LIMITED