GB2062121A

GB2062121A - Lockable pumping device

Info

Publication number: GB2062121A
Application number: GB7937453A
Authority: GB
Original assignee: DINES PLASTICS Ltd
Current assignee: DINES PLASTICS Ltd
Priority date: 1979-10-29
Filing date: 1979-10-29
Publication date: 1981-05-20

Abstract

A lockable pumping device for use, e.g., as a liquid dispenser, comprises a plunger 10 which is reciprocable against the action of a spring 7 relative to a barrel 1 which may, for example, be fitted to a container from which liquid is to be dispensed. The liquid is dispensed via a spout 11 which also constitutes an operating member for the device. The pumping device is lockable by means of one or more keys 16 provided on the plunger 10 and cooperable with an annular groove 18 provided on the inner periphery of a gland 14 fitted to the barrel 1. The key 16 is engageable in the groove 18 by relative rotation of the plunger 10 and barrel 1 so that the key 16 is engageable in a keyway 17 provided in the gland 14. <IMAGE>

Description

SPECIFICATION Lockable pumping device This invention relates to a lockable pumping device.

Many liquid dispensers which are marketed today include a pump comprising a plunger movable within a barrel. However, the plunger can be accidentally knocked causing it to be actuated, resulting in spillage of liquid. Additionally, such dispensers can prove quite awkward to transport because the plungers are normally biassed in a fully extended position outside the body of the dispenser. According to the present invention there is provided a lockable pumping device comprising two members which are relatively reciprocable to cause pumping of a fluid, at least one key associated with one of the members and arranged to cooperate with a groove extending around the axis of reciprocation to lock the members against relative reciprocation and a keyway disposed to permit entry of the key into said groove when the members are in a predetermined rotational position relative to one another.There may of course be a number of keys distributed, preferably equi-angularly, around said axis.

The or each key may take the form of a stud or projection on one of the members. The keyway may be a slot communicating with the groove in a plane substantially perpendicular to the axis of reciprocation.

The device may be a dispensing pump and comprise a plunger movable along the axis of a barrel which has a gland surrounding the plunger at the top of the barrel. The pump may be constructed such that liquid flows through a channel extending longitudinally of the plunger and out through, for example, a spout forming a handle at the top of the plunger. The key may be provided on the plunger, preferably at the top of the plunger adjacent the handle, whilst the gland surrounding the plunger may be provided with a slot, constituting the keyway communicating with the groove which is also formed in the gland.

Alternatively, the gland may be provided with the key and the plunger with a keyway and associated groove. Preferably, the key is integral with the plunger or gland.

The invention will now be described with reference to the accompanying drawing in which the sole figure is a cross-section through a lockable reciprocating pump in accordance with the invention.

The reciprocating pump includes a barrel 1 incorporating a primary chamber 2. At the lower end of the barrel 1, there is a secondary chamber 3, which communicates via a neck 4 to a supply of the liquid which is to be dispensed. A first ball 5 rests in a frustoconical seating 6 in the secondary chamber 3 and acts as a non-return valve to prevent liquid from flowing back out of the primary and secondary chambers during operation of the pump. The ball 5 is prevented from entering the primary chamber 2 by an extension of the spring 7 in the primary chamber which lies across the entrance to the secondary chamber 3. The spring 7 acts against an annular shoulder formed on a hollow piston-connector 8 which carries a piston 9 and is connected to a plunger 10.The plunger 10 has a handle 1 A channel 12, through which liquid to be dispensed flows, is provided along the axis of the plunger 10 and inside its handle 11. A second ball 13 sits at the top of the piston connector 8 and acts as a non-return valve to prevent liquid in the channel 12 from flowing back into the primary chamber 2. The plunger 10 is movable along the axis of a gland 14 which is screwed into the barrel 1 and thereby grips the walls 1 5 of the liquid dispenser to hold the pump in position. The plunger 10 is provided with an integral projection 1 6 which acts as a key.The gland 14 is provided with a slot 1 7 adjacent to the plunger 10 which acts as a keyway and is capable of receiving the key 1 6. The key 1 6 is situated towards the top of the plunger 10 such that in normal operation of the pump the notch does not enter slot 1 7. Slot 1 7 communicates with an inner groove 18.

During normal operation of the reciprocating pump, when primary chamber 2 is full of liquid, the plunger 10 is depressed. This forces the first ball 5 into its seating 6 to prevent liquid exiting via the secondary chamber 3. The second ball 13 is forced off its seating on the piston connector 8 and liquid is forced up the channel 12 and out through the handle 11. When the plunger is released, the spring 7 forces the piston connector 8 and thus the piston head 9 back up the barrel to a position against the underside of the gland 14 whilst the plunger 10 is forced back out of the barrel to its original fully extended position. At the same time the difference in the pressure on either side of the first ball 5 lifts this ball off its seating 6, causing liquid to flow through the neck 4 and the secondary chamber 3 into the primary chamber 2.

Also because of a pressure differential the second ball 13 returns to its seating on the top of the piston connector 8 and prevents liquid flowing back into the primary chamber 2 from the channel 12.

In order to lock the reciprocating pump, the plunger 10 is pushed down further than is usual in normal operation of the pump so that the key 1 6 passes through slot 17 into groove 18. The plunger is then rotated so that the key 1 6 is no longer aligned longitudinally of the plunger with the slot 1 7. The spring 7 thus cannot return the plunger to its original fully extended position but forces the notch 1 6 against the underside of the top surface of the gland 1 4. The plunger is now locked in position. To unlock the plunger, it is rotated until the notch 1 6 coincides with the slot 1 7. The spring 7 will then act to force the plunger back out of the barrel 1 to its original fully extended position.

The groove 18 may slope upwardly in the circumferential direction away from slot 1 7 to provide a detent for the key 1 6 so that in the locked position the plunger has to be depressed during the unlocking action. Means may be provided in order to adjust the limits of travel of the plunger and piston during a pumping stroke so that the volume of liquid pumped per stroke is altered accordingly.

Claims

1. A lockable pumping device comprising two members which are relatively reciprocable to cause pumping ef a fluid and at least one key associated with one of the members and arranged to cooperate with a groove extending around the axis of reciprocation to lock the members against relative reciprocation and with a keyway disposed to permit entry of the key into the groove when the members are in a predetermined rotational position relative to one another.

2. A device according to Claim 1 wherein there are a number of keys distributed equiangularly around the axis of reciprocation.

3. A device according to Claim 1 or 2 wherein the or each key is in the form of a stud or projection on one of the members.

4. A device according to any one of Claims 1 to 3 wherein the or each keyway is a slot communicating with the associated groove in a plane substantially perpendicular to the axis of reciprocation.

5. A device according to any one of the preceding Claims in the form of a dispensing pump, the members being a plunger and a barrel along the axis of which the plunger is movable, the barrel having a gland surrounding the plunger at one end of the barrel.

6. A device according to Claim 5 and constructed such that liquid being dispensed flows through a channel extending longitudinally of the plunger.

7. A device according to Claim 6 wherein the liquid is dispensed via a spout forming a handle at one end of the plunger.

8. A device according to any one of Claims 5 to 7 wherein the or each key is provided on the plunger.

9. A device according to Claim 8 wherein the gland surrounding the plunger is provided with a slot, constituting the keyway communicating with the groove which is also formed in the gland.

10. A device according to any one of Claims 5 to 8 wherein the gland is provided with the key and the plunger is provided with the keyway and associated groove.

11. A device according to any one of the preceding Claims wherein the arrangement is such that relative movement of the two members along their axis of reciprocation beyond the range of movement which, in use, takes place during pumping, is required to engage the or each key with its associated keyway.

-12. A pumping device constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.