The present invention relates generally to dispensers for liquid products and particularly to so-called "trigger pumps" of the kind which have a trigger operable to drive a piston along a pump chamber against the action of a spring and so to force liquid product under pressure from the pump chamber and through a dispensing orifice in an nozzle.

According to a first aspect of the present invention there is provided a trigger pump dispenser comprising: a body; an outlet nozzle; a pump chamber; a piston for defining a variable volume in the pump chamber and movable between a retracted position of larger chamber volume and an inserted position of lesser chamber volume; a trigger coupled with the piston and movable from a starting position at which the piston is in the retracted position and a depressed position at which the piston is in the inserted position; biasing means for biasing the trigger towards its retracted position; an inlet port and an outlet port defined by the body and adapted to be in communication with the pump chamber; an inlet valve adapted to close the inlet port when liquid to be dispensed is in the pump chamber and the piston is moved from the retracted position to the inserted position as the pump chamber decreases in volume, the inlet valve being adapted to open the inlet port when liquid to be dispensed is drawn into the pump chamber through the inlet port as the pump chamber volume increases when the piston is moved from the inserted position to the retracted position, and an outlet valve adapted to open the outlet port when the pump chamber decreases in volume as liquid therein is dispensed through the outlet port and adapted to close when the pump chamber increases in volume, the outlet valve comprises a precompression valve operable to allow liquid through the outlet only after a predetermined elevated pressure is established in the pump chamber, the valve having a movable valve member carried on or by a spring member which biases the valve member to a closed position but flexes in response to the elevated pressure in the chamber acting on the valve member to move the valve member to an open position so that liquid can pass from the chamber and thereafter be dispensed through the outlet nozzle.

This aspeci of the invention therefore provides a precompression function in a pumping cylinder of a trigger sprayer which only allows pressurised liquid to be expelled when the pressure of the liquid in the cylinder is above a certain predetermined level. The precompression system can be used to prevent fluid from being discharge at too low a pressure and allows for an improved spraying pattern as liquid can be pressed out of an outlet nozzle as a predetermined and relatively high pressure.

The spring valve member may compose a flexible annulus which can carry the movable valve member and flex once the predetermined elevated pressure is reached to allow the movable valve member to move to its open position and thereafter return the member to the closed position when the elevated pressure state in the chamber is removed at the end of the pressure stroke.

The valve body member may be inflexible. In other words, it is the spring valve member which flexes in order to move the valve member rather than that valve member itself flexing.

According to an alternative aspect of the present invention there is provided a trigger pump dispenser comprising: a body; an outlet nozzle; a pump chamber; a piston for defining a variable volume in the chamber and thereby pump liquid into and out of the chamber for dispensing through the outlet nozzle; a trigger coupled with the piston and movable to cause the piston to pump liquid; and biasing means for biasing the trigger to a retracted position; the nozzle is movable from a first position in which it is in fluid communication with the pump chamber and a second position in which fluid communication is blocked, the pump comprising child-resistant locking means for locking the nozzle in the second position and which must be released to allow movement to the first position.

This aspect of the present invention therefore provides a safety feature which can lock the trigger pump in a closed position in which liquid cannot be dispensed through the outlet nozzle. A child-resistant feature is provided on the pump, for example on the nozzle itself, which must be disengaged before the nozzle can be moved to a position in which liquid can be dispensed there through. In one embodiment the locking means comprises a resilient member provided on the nozzle and movable between a locked position and an unlocked position. The combination ot a requirement for the locking means to be disengaged as well as the nozzle to be moved to the second position can be used to provide an effective child- resistant feature.

According to a further aspect there is provided a trigger pump dispenser comprising: a body; an outlet nozzle; a pump chamber; a dispensing passage; a piston for defining a variable volume in the chamber and thereby pumping liquid into and out of the chamber for dispensing through the nozzle via the dispensing passage; a trigger coupled with the piston and movable to cause the piston to pump liquid; biasing means for biasing the trigger to a retracted position; a shroud; the nozzle is movable from a first 'on' position in which it is in fluid communication with the dispensing passage and a second, 'off position in which fluid communication is blocked, the nozzle having indicator means carried on or by the nozzle body which are alternatively brought into register with windows on the shroud to indicate if the nozzle is in the On' or 'off position.

Aspects of the present invention and embodiments thereof may be provided in combination with a container. Aspects and embodiments of the present invention may be used separately or in combination.

The present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a section of a trigger pump dispenser formed according to an embodiment of the present invention; Figure 2 is a section of a trigger pump dispenser formed according to an alternative embodiment of the present invention;

Figure 3 is a side elevation of a piston forming part of the dispenser of Figure 1 ; Figure 4 is a side elevation of a piston forming part of the dispenser of Figure 2;

Figure 5 is a section of an outlet valve forming part of the dispenser of Figure 1 and shown in a closed position; Figure 6 is a section of the valve of Figure 5 shown in an open position;

Figure 7 is a perspective view of a child-resistant spray nozzle formed according to an alternative embodiment of the present invention; Figure 8 is a section of the nozzle arrangement of Figure 7;

Figure 9 is a rear perspective view of the nozzle of Figures 7 and 8; Figure 10 is a perspective view of a dispensing barrel forming part of the dispenser shown in Figure 8; and

Figure 1 1 is a perspective view of a nozzle arrangement formed according to an alternative embodiment.

Referring first to Figure 1 there is shown a trigger pump dispenser generally indicated 10.

The dispenser comprises: a nozzle 15; a dispensing barrel 20; a shroud 25; a trigger 30; a piston 35; a pump cylinder 40; a closure 45; an inlet valve 50; an outlet valve 55; and a dip tube όθ.

The trigger 30 can be used to cause the piston 35 to move within the cylinder 40. The interior of the cylinder 40 defines a pump chamber the effective volume of which is defined by the piston 35. Movement of the piston 35 to increase the pump chamber volume causes fluid from an associated container (not shown) to be drawn up through the dip tube 60 and into the cylinder 40 via the inlet valve 50. During this "sucking" stroke the inlet valve 55 remains shut. When the trigger 30 is pulled towards the closure 45 the piston 35 is moved to decrease the pump chamber volume. This causes the inlet valve 50 to shut and the outlet valve 55 to open as described in more detail below with reference to Figures 5 and 6. Liquid from the pump chamber flows through a dispensing passage 21 in the barrel to the nozzle 15 for dispensing.

In order to return the trigger to the rest position a spring (not shown for clarity) is provided which biases it to the rest position.

Referring now to Figures 5 and 6 the outlet valve 55 is shown in more detail. In Figure 5 the valve 55 is shown in the closed position. In this position an outlet port 42 from the pump chamber 1 is blocked and liquid in the chamber 1 cannot pass into an outlet passage 43 that leads to the dispensing barrel. The valve 55 comprises a movable valve member 56 which is supported on an annular spring member 57. The member 56 comprises a disc-shape pressure plate 58 from the periphery ot which the spring 57 extends. At the other end of the spring 57 an annular retention leg 59 projects and is used to hold the valve 55 against the pump chamber cylinder 40. A stop block 59A projects from the reor face of the pressure disc 58.

In this embodiment the valve 55 is formed from a thermoplastic elastomer material and is carried on a base 65 formed from polypropylene, which gives a degree of rigidity to the structure. In use, as the piston causes a decrease in the pump chamber volume pressure builds up agoinst the disc 58. The disc 58 is held in position by the spring 57 until a predetermined pressure threshold is reached after which the disc 58 is pushed away from the outlet 42 as shown in Figure 6. The disc 58 itself is inflexible and moves by virtue of the flexing of the spring 57. This causes the valve 55 to move away from the outlet 43A at the entrance to the passage 43 so that liquid can be forced from the chamber 1 into the passage 43 and onward for dispensing.

Referring now to Figure 2 there is shown a trigger pump 1 10 formed according to an alternative embodiment. The pump 1 10 is identical to the pump 10 shown in Figure 1 except that the piston 135 is longer as also illustrated in Figures 3 and 4 showing the pistons 35, 135 from Figures 1 and 2 respectively.

Both pistons 35, 135 are provided with identical connection means 36, 136 for connecting them to the trigger 30, 130. By providing standardised interconnection means different sized pistons can easily be substituted into the remainder of the dispenser. By providing a longer piston for the dispenser 1 10 the maximum fill volume of the pump chamber 1 ) is effectively decreased, as is the stroke length. This means that a dispenser with a lower capacity is easily formed.

Referring now to Figures 7 to 10 there is shown a child-resistant nozzle arrangement formed according to an alternative aspect of the present invention.

The nozzle 215 is rotatably connected to the end of a dispensing barrel 220. The dispensing barrel 220 includes an arcuate dispensing outlet 222 through which liquid to be dispensed must flow.

The nozzle 215 can be rotated relative to the barrel 220 between an open and a closed position which are 180° apart. In an open position the nozzle inlet is aligned with the discharge outlet 222 of the barrel 220; whereas in the closed position the inlet and outlet are not aligned. The nozzle can thereby be moved into and out of fluid communication with a pump chamber.

The nozzle 21 5 is provided with a tamper evident locking pin 216 shaped to fit into a notch 223 formed in a locking plate 224 on the barrel 220. When the pin 21 is engaged in the notch 223 the nozzle 215 cannot be rotated. The pin 216 is carried on a resilient arm 21 7 which supports a push tab 218.

In order to disengage the pin 21 6 from the notch 223 the pull tab 21 6 is pushed away from the barrel plate 224. The nozzle 215 can now be rotated so that the outlet 222 is in alignment with its inlet and product can be dispensed. In the open position the pin 216 rests in a further notch 223A which is opposite the notch 223 on the plate 224. Each side of the notch 223A is defined by an inclined edge 223B. Because the edges 223B are inclined, the nozzle can be moved from the open position to the closed position without the need to move the tab 218 because the pin 216 can ride up the edges 223B so as automatically to disengage it from the slot 223A.

The nozzle 215 is provided with two identical semi-circular tabs 219 A, 219B. The tab 219 A is positioned so that when the nozzle 215 is in the off position as shown in Figure 7 the tab 219 A resides in a semi-circular cut-out 226A provided on the cowl 225. Similarly, the tab 21 B is positioned so that when the nozzle 215 is rotated to the on position it resides in a cut-out 222B in the cowl 225. A clear indication of whether the nozzle is in the on or off position is thereby provided, as well as an effective child-resistant functionality.

Referring now to Figure 1 1 there is shown a nozzle 315 formed according to an alternative embodiment. The nozzle 315 is similar to the nozzle 215 of Figures 7 to 9, except that in this embodiment there is no child-resistant feature; so the nozzle is freely movable between the on and off positions. The nozzle 315 is again provided with indicator tabs which alternately become visible in different respective windows 322a, 322b in the upper surface of the shroud 325 depending on the open/closed status of the nozzle.

It will be appreciated that the different aspects and embodiments described herein can be used together or separately.