WO1994008726A1

WO1994008726A1 - A pump dispenser

Info

Publication number: WO1994008726A1
Application number: PCT/GB1993/002161
Authority: WO
Inventors: Miro S. Cater
Original assignee: Bespak Plc
Priority date: 1992-10-21
Filing date: 1993-10-20
Publication date: 1994-04-28
Also published as: EP0665771A1; TW262522B; CN1087294A; US5335830A

Abstract

A dispenser has a piston (4) slidable in a first cylinder (11) connected to a second cylinder (12) of smaller diameter. A first tubular member connected to the piston provides a discharge passage and a second tubular member extends through the first cylinder into the second cylinder during the actuating stroke. A sliding seal is formed between the second tubular member and the second cylinder and an aperture (26) provided in the second tubular member acts as both inlet and outlet port during the actuating stroke and return stroke respectively. A valve member (31) controls direction of flow through the aperture and is axially movable by a stem extending through the first tubular member and connected to an actuator (60). Lost motion between the piston and stem provides automatic actuation of the valve member and can be selectively locked to provide locking means preventing discharge. The pump dispenser is particularly suited for dispensing lotions.

Description

A PUMP DISPENSER

Pump dispensers are manually operated devices typically disposed on the top of a container of fluid for dispensing the fluid in a desired form from a dispenser nozzle. Dispensers of this type as disclosed for example in US 5,046,644 employ a piston which is reciprocatable in a cylinder to vary the volume of a pump chamber and inlet and outlet ports individually controlled by valve means for opening and closing them to allow fluid to enter and leave the pump chamber.

The present invention is directed toward a new type of pump dispenser having a simplified structure having fewer and less complicated components and anufacturable at significantly reduced cost. This dispenser also has other advantages as described in more detail below.

According to the present invention there is disclosed a dispenser comprising a first cylinder, a piston slidable in the first cylinder to vary the volume of an annular pump chamber defined therein, a first tubular member integral with the piston and extending outwardly of the first cylinder and through which a discharge passage extends, a second tubular member constituting an inner wall of the annular pump chamber and defining a bore communicating with a liquid supply means, a valve member slidably received in the bore and co-operable in a rest position of the valve member with a valve seat defined by the piston to close the discharge passage, and a stem connected to the valve member and extending through the first tubular member, characterised by the second tubular member being integral with the piston and defining an aperture comprising one or more openings communicating between the chamber and the bore and by the valve member being movable relative to the aperture in response to relative movement of the stem and piston between an actuated position in which the chamber communicates with the dispensing channel via the aperture and the rest position in which the chamber communicates with the liquid supply means via said aperture.

Preferably the dispenser comprises a second cylinder formed integrally and co-axially with the first cylinder, the second cylinder having a smaller diameter than that of the first cylinder and having an internal surface sealingly engaged by an annular periphery of the second tubular member.

An advantage of the continuous sliding sealing contact with the second tubular member is that smooth operation without clogging is ensured.

The second cylinder may optionally comprise a re-entrant tubular section having an outer cylindrical surface sealingly engaged by the annular periphery of the second tubular member.

An advantage of such a re-entrant tubular section is that it provides a suitable support for a dip tube.

The dispenser may comprise a spring located externally of a body constituted by the first and second cylinders and engaging an actuator mounted on the stem to bias the actuator and stem away from the body.

An advantage of locating this spring externally of the body is that it does not come into contact with fluid within the dispenser. It is therefore possible to manufacture the dispenser such that the only metal component is the spring which does not contact the fluid to be dispensed. Alternatively the spring may be located in the bore and may engage the valve member so as to bias the valve member into the rest position and the stem outwardly of the first cylinder.

Conveniαntly the dispenser comprises an actuator fixedly connected to an end portion of the stem and connection means operable between the first tubular member and the actuator such that lost motion is provided between reciprocating movement of the stem and the first tubular member.

The dispenser may comprise locking means selectively operable to prevent relative axial movement between the stem and the first tubular member so as to selectively lock the valve member in a position in which the discharge passage is closed. Conveniently the locking means comprises co-operating key formations of the first tubular member and the actuator whereby the locking means is actuable by rotation of the actuator relative to the first tubular member.

In use, the body is connected to a container of fluid in such manner that fluid in the container can be drawn upward into the body via an opening in the lower end of the second cylinder. The structure is initially primed with fluid which is stored in the pump chamber. This is the rest position. When the actuator coupled to the piston and stem is manually depressed, a downstroke is initiated. The downstroke produces a downward movement first of the stem relative to the piston and then to both piston and stem. The initial movement of the stem moves the valve member away from the piston and opens the discharge path. This movement at the same time moves the valve member into alignment with the aperture and temporarily closes it. The additional downward movement moves the valve member below the aperture which is then opened and functions as an outlet port. The fluid stored in the chamber is discharged through the aperture, the discharge path and a discharge nozzle in the actuator. This discharge continues until the end of the downstroke. Removal of the manual pressure on the actuator initiates an upstroke, with the stem first moving upward relative to the piston to cause the valve member to close the discharge path. The aperture then functions as an inlet port, with fluid being drawn upward into the bore and passing through the aperture into the chamber. The actuation cycle is completed once the stem and piston have returned to their original positions and the valve member is returned to its rest position. Consequently, the dispenser utilises an aperture to act as an outlet port during a downstroke and to act as an inlet port during an upstroke. The seals formed by the sliding engagement of the piston and the inner surface of the first cylinder, the sliding engagement of the second tubular member and the inner surface of the second cylinder, and the sliding engagement of the valve member with the inner surface of the second tubular member are always in sliding contact which provide a self cleaning, wiping action.

It will be apparent to those skilled in the art that the basic pump dispenser disclosed herein is constructed of four basic parts: a body consisting of two cylinders of dissimilar diameters, the diameters of the two cylinders defining an outer boundary of a pump chamber; a piston which defines the inner boundary of the pump chamber, forming a slidable seal with both body diameters and provided with an aperture which can function as an inlet port and an outlet port; a stem which cooperates with the piston to form a discharge path which can be opened or closed and cooperates with the aperture to define an outlet port during a downstroke and an inlet port during an upstroke; and a spring to place the valve member in its rest position. Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings of which:

Figure 1 is a schematic sectional elevation of a dispenser in its rest position; Figure 2 is a schematic sectional elevation of the dispenser of Figure 1, illustrating the discharge of fluid during a downstroke;

Figure 3 is a schematic sectional elevation of the dispenser of Figures 1 and 2 illustrating the recharging of the pump chamber during the upstroke; Figure 4 is a sectional elevation of a preferred embodiment of a dispenser in accordance with the present invention shown at rest;

Figure 5 is a sectional plan view of the dispenser of Figure 4 taken along line 5-5;

Figure 6 is a sectional plan view of the dispenser of Figure 4 taken along line 6-6;

Figure 7 is a sectional elevation of an alternative dispenser utilising a spring disposed outside of the body and incorporating a locking mechanism;

Figure 8 is a sectional plan view through line A-A in Figure 7 showing the dispenser in an unlocked position; Figure 9 is a sectional plan view through line A-A in Figure 7 showing the dispenser in a locked position;

Figure 10 is a sectional plan view taken at B-B in Figure 7; Figure 11 is a sectional plan view through C-C in Figure 7; Figure 12 is a sectional plan view through line B-B in Figure 7 showing the dispenser in an unlocked position;

Figure 13 is a plan section at D-D of the dispenser in Figure 7 at a transitionary position in between unlocked and locked positions;

Figure 14 is a sectional plan view through line D-D of the dispenser of Figure 7 shown in the locked position; Figure 15 is a sectional plan view through line C-C in Figure 7;

Figure 16 is a sectional elevation of a further alternative embodiment using a spring disposed within the body; Figure 17 is an enlarged detail perspective view of the top portion of the piston of Figure 7;

Figure 18 is a sectional elevation of the dispenser of Figure 7 shown in active stroke and illustrating the discharge path; Figure 19 is a sectional elevation of the dispenser of Figure 7 showing the refill path in the return stroke and the path which empties the contents of the pump chamber into the container during the lock-down stroke; Figure 20 is a sectional elevation of the dispenser of Figure 7 in its locked down position; and

Figure 21 is a sectional elevation of a further modified form of the dispenser of Figure 7 which lacks the locking and unlocking mechanism of Figure 7. Referring first to Figures 1-3, a dispenser 1 has a body 2 having integral upper and lower vertical hollow cylinders 300 and 302 with a common vertical axis 3. (The terms "upper" and "lower" refer to the relative positions of elements of the dispenser when oriented in its normal operating position, this terminology being adopted throughout the following description.) The diameter of the upper cylinder 300 is larger than the diameter of the lower cylinder 302. The upper cylinder 300 has a first central opening 304 in its lower end communicating with the lower cylinder 302.

A piston 4 is slidable in said body 2. The piston 4 has a first tubular member in the form of a vertical hollow cylindrical upper section 5 open at upper and lower ends 306, 307 respectively, a first extension 308 projecting radially from the outer surface of the lower end 307 and a second tubular member in the form of an axially extending second extension 301. The second extension 310 has upper and lower ends 309 and 311 respectively, the lower end 311 being open, and radially extending openings together constituting an aperture 312 being defined by the second extension located intermediate the ends 309 and 311 of the second extension 310. Typically, the aperture 312 comprises two or more circu ferentially equispaced openings which are horizontally aligned so as to have the same axial position relative to the second extension 310.

The first extension 308 is always in peripheral sealing engagement with an inner surface of the upper cylinder 300. The second extension 310 has an outer surface 313 and is always in peripheral sealing engagement with an inner surface 303 of the lower cylinder 302. An annular pump chamber 13 is defined within the upper cylinder 300 and is bounded at its inner radius by the second extension 310. The second extension 310 defines a cylindrical bore 14 communicating with the aperture 26.

A vertical stem 314 is slidable within and extends through the upper section 306 of the piston 5. The stem 314 and the upper section 5 of the piston 4 are radially spaced apart to define a vertical discharge path 316 therebetween. The stem 314 has an enlarged head 318 constituting a valve member which is always in slidable peripheral sealing engagement with an inner surface 315 of the second extension 310 of the piston 4. The head 318 has a rest position as shown in Figure 1 at which the head is disposed above the apertures 312 and at the same time engages the lower end 307 of the upper section 5 to close the discharge path 316. By forming a radial seal in the bore 14 the valve member or head 318 thereby constitutes a shuttle valve mechanism.

A spring 320 cooperating with the stem 314 normally biases the head 318 into the rest position. The spring 320 is disposed between a lower end wall 317 of the lower cylinder 302 and the head 318.

In use, the body 2 is connected to a container of fluid (not shown) in such manner that a supply of fluid in the container can be drawn upward into the body via an opening 322 in the lower end wall 317 of the lower cylinder 302 and into the bore 14. The dispenser is primed with fluid being stored in the pump chamber 13.

When an actuator 60 (of the type shown for example in Figure 4) coupled to the piston 4 and stem 314 is manually depressed, a downstroke is initiated. The downstroke produces a downward movement first of the stem 314 relative to the piston 4 and then to both piston and stem. The initial movement of the stem 314 moves the head 318 away from the piston 4 and opens the discharge path 316. This movement at the same time moves the head 318 into alignment with the apertures 312 and closes them. The additional downward movement moves the head 318 below the apertures 312 which then open and function as an outlet port as shown in Figure 2. The fluid stored in the upper cylinder 300 is discharged through the ape ;ures 312, the discharge path 316 and through a discharge nozzle 70 in the actuator 60. This discharge continues until the end of the downstroke. Removal of the manual pressure on the actuator 60 initiates an upstroke, with the stem 314 first moving upward relative to the piston 4 to cause the head 318 to close the discharge path 316. The apertures 312 then function as an inlet port 327 as shown in Figure 3 with fluid being drawn upward into the lower cylinder 302 and passing from the lower cylinder through the aperture 312 into the upper cylinder 300. The actuation cycle is completed once the stem 314 and piston 4 have returned to their original positions and the head 318 is returned to its rest position as shown in Figure 1.

Consequently, the dispenser 1 utilises the same apertures 312 to act as an outlet port 325 during a downstroke and to act as an inlet port 327 during an upstroke. The sliding engagement of the first extension 308 and the inner surface 301 of the upper cylinder 300, the sliding engagement of the second extension 310 and the inner surface 303 of the lower cylinder 302, and the sliding engagement of the head 318 with the inner surface 315 of the second extension 310 provide a self cleaning, wiping action.

Referring now to Figures 4, 5, and 6, a preferred embodiment of the invention is provided by a dispenser 401 which utilises a body 400 comprising a hollow upper cylinder 11 having a first diameter and an integral hollow lower cylinder 12 having a second and smaller diameter.

A piston 404 has a vertical hollow upper section 20, a radially projecting first extension 21 having a large sealing periphery 405 which is in continuous sealing engagement with an inner surface 406 of the upper cylinder 11 and a second extension 22 of smaller radius which extends axially downward below the first extension. The inner surface 407 of the upper section 20 is generally cylindrical with a radially enlarged conical seat 25 formed at its lower end. The second extension 22 takes the shape of a vertical hollow cylinder having open upper and lower ends, the upper end being integral with the lower end of section 20. The lower end of the second extension 22 has a sealing periphery 408 which is in continuous sealing engagement with an inner surface 409 of the lower cylinder 12. The second extension 22 has two radially extending apertures 26 which are horizontally aligned and are circumferentially equidistantly spaced.

A stem 30 is slidably disposed within the piston 404, being radially spaced inwardly from the upper section 20 to define a discharge passage 96 therebetween. The stem 30 has at its lower end an enlarged solid head 31 having an upper surface conforming to that of the conical seat 25. The bottom surface of the head 31 is an annular flat surface 94 which is peripheral to a downwardly projecting flat disc. The head 31 has a vertical outer surface 27 which has a sealing periphery always in continuous sealing engagement with the inner surface 409 of the second extension 22.

An annular shoulder 90 is formed between the upper end of the lower cylinder 12 and the lower end of the upper cylinder 11. The annular shoulder 90 acts as a lower stop for the downward movement of the first extension 21. The lower end of the lower cylinder 12 is re-entrant to provide an inwardly and upwardly extending tubular section 410 with an inlet opening 98. This tubular section 410 may in an alternative arrangement (not shown) extend downwardly from the lower cylinder 12 if desired. In either event, a second annular shoulder 92 is formed between the tubular section 110 and the lower end of the lower cylinder 12. A spring 80 is disposed in the dispenser 401 with its lower end engaging the second annular shoulder 92 and its upper end bearing against annular flat surface 94 of the head 31.

An actuator 60 is rigidly secured to a top end portion 61 of the stem 30. A passage 62 is formed between the top end portion 61 of the stem 30 and the actuator 60 to provide fluid communication between the discharge path 96 and a nozzle 70 forming part of the actuator. A gap 67 is formed between an upper end surface 411 of the upper section 20 of the piston 404 and a recess 63 in the actuator 60. The upper section 20 makes peripheral contact against the recess 63 and remains in sliding sealing engagement therewith. The upper end of the upper cylinder 11 is mounted in a collar 40 which is surrounded by a mounting means or cup 50. Cup 50 is secured to the neck of a fluid container (not shown) and in conventional manner an air intake path 100 is formed therebetween.

In the rest position, shown in Figure 4 the head 31 engages the conical seat 25 and closes the discharge path 96. In this position, the head 31 is disposed above the apertures 26. When downward pressure is applied to the actuator 60, the actuator and stem 30 travel downwards against an upward force of the spring 80 while frictional forces between the respective cylinders 11, 12 and extensions 21, 22 initially maintain the piston 404 motionless. The depth of the gap 67 decreases progressively. The conical seat 25 and the head 31 begin, to separate as the stem 30 moves downwardly relative to the piston 404 while the head moves into alignment with the apertures 26 and closes them. As the actuation continues, the gap 67 is reduced to zero, the piston 404 is forced downward by the actuator 60, the discharge path 96 is opened, and the head 31 moves below the apertures 26 and opens them. Fluid is then forced out of the upper cylinder 11 as the available volume is reduced because of the downward movement of the piston 404 and is further forced through the apertures 26, the discharge path 96 and the discharge passage 62 for discharge through the nozzle 70.

Once the downward pressure is removed from the actuator 60, the spring 80 forces the stem 30 and actuator upwards. The frictional forces between the respective extensions 21, 22 and the cylinders 11, 12 maintain the piston 404 initially motionless until the head 31 engages the conical seat 25 and closes the discharge path 96. The piston 404 and stem 30 move upwards, producing a suction which draws fluid within the lower cylinder 12 through the apertures 26 and into the upper cylinder 11. This process continues until the piston 404 and stem 30 are returned to the rest position as shown in Figure 4 and the head 31 is then returned to its rest position.

Figure 7 with the accompanying cross sections shown in Figures 8 to 15 and 17 to 20 illustrates an alternative dispenser 700 which uses a spring 701 disposed outside of a body 702 and incorporates a locking mechanism. Figure 21 illustrates a modification of the embodiment of Figure 7 wherein the locking mechanism has been eliminated. Figure 16 shows an embodiment similar to that of Figures 7 to 20 which uses a spring 702 disposed within the body and incorporates the same locking mechanism. Referring first to Figures 7 to 15 and 17 to 20 the alternative dispenser 700 will now be described using corresponding references to those of preceding Figures for c . responding elements where appropriate. The dispenser 700 has a body 702 comprising an upper cylinder 11 having a first diameter and an integral hollow lower cylinder 12 having a second diameter which is smaller than the first diameter.. A piston 4 has a vertical hollow upper section 20, a radially projecting first extension 21 having a sealing periphery which is in continuous sealing engagement with the inner surface 406 of the upper cylinder 11 and a second extension 22 of smaller diameter which projects axially downwardly below the first extension. The lower end of the upper section 20 defines a conical seat 25. The second extension 22 takes the shape of a vertical hollow cylinder having open upper and lower ends, the upper end being integral with the lower end of the upper section 20. The lower end of the second extension 22 has a sealing periphery which is in continuous sealing engagement with the inner surface of the lower cylinder 12. The second extension 22 has two radially extending apertures 26 which are horizontally aligned and are circumferentially equispaced.

A stem 30 is slidably disposed within the piston 4, being radially spaced inwardly from the upper section 20. The stem 30 in horizontal cross section consists of three circumferentially equidistantly spaced legs 703 defining three discharge passages 96 therebetween. An enlargement in the form of an annular shoulder 731 connects the upper and lower portions. The shoulder 731 is engagable with the seat 25 to form a seal therewith. The shoulder 731 has a vertical outer surface 27 which has a sealing periphery always in continuous sealing engagement with the inner surface of the second extension 22. An annular shoulder 90 is formed between the upper end of the lower cylinder 12 and the lower end of the upper cylinder 11. The shoulder 90 provides a lower stop for downward movement of the upper extension 21. The lower end of the lower cylinder 12 has an inlet opening 98 through which a dip tube (not shown) can extend, the dip tube being arranged to extend into a body of liquid in the container.

An actuator 60 is rigidly secured to a top end portion 61 of the stem. A passage 62 is formed between an upper portion of the stem and the actuator 60 to connect the discharge path 96 to a nozzle 70. A gap 67 is formed between an upper end of the upper section 20 of the piston and a recess 63 in the actuator. The upper end of the upper section 20 seals against the recess 63 so as to remain in sliding peripheral engagement therewith.

The upper end of the lower cylinder 11 is mounted in a collar 40 which has upwardly extending coaxial inner and outer hollow cylindrical portions 44 and 42 respectively. Both portions 44 and 42 are open at their upper ends. The inner portion 44 is open at its lower end. The upper section 20 of the piston is in sliding engagement with the interior surface of the outer portion 44. Actuator 60 has a cylindrical hollow lower section 46 in the form of a depending skirt open at its lower end and which slides into portion 42 when the actuator is depressed.

A spring 80 is disposed outside of the body 702 so as to bear at its lower end against the collar 40 and at its upper end against the inner surface of the lower section 46 of the actuator 60, thus applying an upwardly exerted biasing force against the actuator and the stem 30, the stem being secured to the actuator.

Thus the spring 80, which is the only metal component used in the dispenser 700, is disposed out of contact with the fluid in the dispenser.

The outer cylindrical portion 44 of the collar terminates at its lower end in outer and inner frustoconical surfaces 148 and 149 which seal against the piston 4 when in its fully raised position as shown in Figure 7. The outer cylindrical portion 44 has at its upper end an internal frustoconical surface 140 which seals against the actuator 60 when the actuator is in its fully lowered position as shown in Figure 15, in between these fully raised and fully lowered positions, air is vented to the container via path 100 as shown in Figure 7.

In the rest position, the shoulder 731 engages the seat 25 and closes the discharge path 96. In this position, the shoulder 731 is disposed above the apertures 26.

When downward pressure is applied to the actuator 60, the actuator and the stem 30 travel downwards against the force of the spring 80 while the frictional forces between the respective cylinders 11, 12 and the extensions 21, 22 initially maintain the piston 4 motionless. The depth of the gap 67 decreases progressively. The seat 25 and the shoulder 731 begin to separate as the stem 30 moves downwardly relative to the piston 4 while the shoulder 731 moves into alignment with the apertures 26 and closes them. As the actuation continues, the gap 67 is reduced to zero, the piston 4 is forced downward by the actuator 60, the discharge path 96 is opened, and the shoulder moves below the apertures 26 and opens them. The fluid is forced out of the upper cylinder 11 as the available fluid volume is reduced because of the downward movement of the piston 4 and is further forced through the apertures 26, the discharge path 96 and the passage 62 for discharge through the nozzle 70.

Once the downward pressure is removed from the actuator 60, the spring 80 forces the stem 30 and actuator upwards. The frictional forces between the respective extensions 21, 22 and the cylinders 11, 12 maintain the piston 4 initially motionless until the shoulder 731 engages the seat 25 and closes the discharge path 96. The piston 4 and stem 30 move upwards, producing a suction which draws the fluid upward via the lower cylinder 12, through the apertures 26 and into the upper cylinder 11. This process continues until the piston 4 and stem 30 are returned to the rest position shown in Figure 7 and the shoulder 731 is then returned to its rest position. The structure of Figure 16 is shown in simplified form, since it functions in essentially the same manner as the embodiment of Figure 7 except that the simplified structure incorporates a spring 80 disposed within the fluid path. The structure of Figure 16, absent the locking means described in detail below, is described in more detail with reference to Figure 1.

Referring now to Figure 16, an alternative dispenser 704 will now be described using corresponding references to those of preceding Figures where appropriate for corresponding elements. The dispenser 704 utilises a hollow upper cylinder 11 having a first diameter and an integral hollow lower cylinder 12 having a second diameter which is smaller than the first diameter.

A piston 4 has a vertical hollow upper section 20, a radially projecting first extension 21 having a sealing periphery which is in continuous sealing engagement with the inner surface of the upper cylinder 11 and an axially projecting second extension 22. The lower end of the upper section 20 has an annular seat 25. The second extension 22 takes the shape of a vertical hollow cylinder having open upper and lower ends, the upper end being integral with the lower end of the upper section 20 of the piston 4. The second extension 22 has apertures 26 which are horizontally aligned and are circumferentially equispaced. The lower end of the second extension 22 has a sealing periphery which is in continuous sealing engagement with the outer surface of a re-entrant tubular section 410 of the lower cylinder 12, the interior of which receives a dip tube 91.

A hollow stem 30 is slidably disposed within the upper section 20 of the piston 4. The stem 30 is open at its upper end and has a radial enlargement in the form of a disc 705 at its lower end. The stem 30 has a radially extending opening 304 located adjacent but above the disc 705. The hollow interior of the stem 30 defines a vertical discharge path 68 communicating with the opening 304 for the fluid as will be explained below. The disc 705 can engage the seat 25 to close the discharge path 68 at its lower end. The disc 705 has a vertical outer surface 27 forming a sealing periphery always in continuous sealing engagement with the inner surface of the second extension 22 of the piston 4.

The lower end of the lower cylinder 12 has an inlet opening 98 through which the dip tube 91 extends. This opening is defined by the bottom open end of the re-entrant tubular section 410 extending upwardly and concentrically within the lower cylinder 12. The separation between the lower cylinder 12 and the tubular section 410 defines an annular region 706. The lower end of the second extension 22 can be lowered into the region 706 while remaining in continuous sealing engagement with the outer surface of the tubular section 410.

An actuator 60 is rigidly secured to a top end portion 61 of the stem. A passage 62 defined within the actuator connects the discharge path 68 to a dispensing nozzle 70. A gap 67 is formed between the upper end of the upper section 20 of the piston 4 and a recess 63 in the actuator 60. The upper section 20 seals peripherally against the recess 63 and remains in sliding engagement therewith. The upper end of the upper cylinder 11 is mounted in a collar 40 which has an upwardly extending hollow cylindrical projection 707. The upper section 20 of the piston 4 is in sliding engagement with the internal surface of projection 707.

A spring 80 is disposed inside the body 2 of the dispenser 704 and bears at its lower end against the upper end of the tubular section 410 of the lower cylinder 12 and bears at its upper end against the disc 705, thus applying an upwardly exerted biasing force against the stem 30.

In the rest position, the disc 705 seals against the seat 25 and closes the discharge path 68. In this position, the disc 705 is disposed above the apertures 26 and blocks access of fluid to the opening 304.

When downward pressure is applied to the actuator 60, the actuator and the stem 30 travel downwards against the force of the spring 80 while the frictional forces between the respective cylinders 11, 12 and the extensions 21, 22 maintain the piston 4 initially motionless. The depth of the gap 67 decreases progressively. The disc 705 begins to separate from the seat 25 as the stem 30 moves downwardly relative to the piston 4 while the outer surface 27 of the disc moves into alignment with the apertures 26 and closes them. As the actuation continues, the gap 67 is reduced to zero, the piston 4 is forced downward by the actuator, the discharge path 68 is opened, and the disc 705 moves below the apertures 26 and opens them. The fluid is forced out of the upper cylinder 11 as the available fluid volume is reduced because of the downward movement of the piston 4 and is further forced through the apertures 26, the opening 304, the discharge path 68 and the passage 62 for discharge through the nozzle 70.

Once the downward pressure is removed from the actuator 60, the spring 80 forces the stem 4 and actuator upwards. The frictional forces between the respective extensions 21, 22 and the cylinders 11, 12 maintain the piston 4 initially motionless until the disc 705 engages the apertures 26 and closes the discharge path 68. The piston 4 and the stem 30 move upwards, producing a suction which draws the fluid upwardly through the lower cylinder 12, through the aperture 26 and into the upper cylinder 11. This process continues until the piston 4 and stem 30 are returned to the rest position and the disc is then returned to its rest position. The embodiments of Figure 7 and Figure 16 utilise a locking mechanism 708 as described below which is common to the piston 4 and actuator 60 for interconnecting the piston and actuator in such manner that the dispenser can be placed in a locked down position without actuation.

As has been explained above, some relative vertical motion between the actuator 60 and the upper section 20 of the piston 4 takes place in order to initiate the discharge of fluid. If this lost motion does not take place, there can be no discharge. The locking mechanism 708 selectively inhibits this relative motion, thus preventing actuation.

The description that follows refers to Figures 8 to 14.

The upper section 20 of the piston 4 has two identical circumferentially equidistantly spaced axial slots 201 whose length is equal to the stroke of the pump. Each of these slots 201 engages a respective mating tooth 201A integral with the outer cylindrical portion 44 of the collar 40 and projecting radially inwards into central opening 250 defined by the collar. During normal actuation, the angular position of the piston remains aligned with the collar 40 such that the teeth 201A ride within the slots 201. The top surface 203 of the upper section 20 of the piston is indented to incorporate a key slot 202 which is normally aligned with a tooth 202A projecting downwardly of the actuator 60. A gap 67 is formed between the surface 203 and the bottom of the recess 63 in the actuator 60. An equivalent gap 67A is formed between the bottom of the key slot 202 and the end face of the tooth 202A. The bottom of the key slot 202 is spaced below the top surface by twice the length of the gap 67. During normal actuation of the dispenser both gaps 67 and 67A are reduced to zero in the manner previously described.

However half way down the length of key slot 202, a secondary horizontal step 204 extends from one vertical wall of the key slot 202 half way to the other vertical wall. The actuator 60 can be rotated about its vertical axis to align the tooth 202A with the step 204 whereby the actuator and the upper section 20 of the piston are so aligned that the gap 67A cannot be reduced. Consequently, during a downstroke with the actuator 60 and piston 4 aligned in this fashion, the stem 30 cannot move relative to the piston and the discharge path 68 remains closed by the head 31 while the fluid inlet path via the aperture 26 remains open. The contents of the fluid in the pump chamber 13 are displaced during this downstroke downwardly back into the container.

It is also possible to lock the dispenser 700 in the fully actuated locked position in which the actuator remains fully depressed by actuation of a further locking device which is operated by rotating the actuator clockwise while pushing it down as shown in Figure 20.

When the actuator 60 is rotated clockwise, the tooth 202A is first positioned above the step 204. This actuates the locking mechanism to maintain the discharge path closed during further actuation as described above. Continued rotation causes tooth 202A to engage a vertical wall 205 of the slot 204 and causes the piston to rotate. The teeth 201A are disengaged from the axial slots 201 and move upward along respective helical surfaces 207 formed externally on the upper section 20 as shown in Figure 17. At the bottom of the downstroke, the teeth 201A engage corresponding upper slots 208. Vertical outwardly extending ridges 206 are disposed between slots 201 and 208 to retain the teeth 201A in slots 208 formed in the upper section 20. The dispenser is then locked in the down position.

In order to unlock the dispenser from this position, the actuator 60 is rotated counterclockwise, causing tooth 202A to engage the opposite wall of key slot 202. Further rotation causes the teeth 201A to become disengaged from slots 208 and engage the helical surfaces 207. The spring 80 forces the piston 4 upward and the teeth 201A move downward along the helical surfaces 207 to become re-engaged with the axial slots 201. This completes the upstroke and returns the actuator and piston 4 to their rest position. During the upstroke, the cylinder 11 is refilled with fluid. Dispensers in accordance with the present invention may employ biassing means other than the metal coil springs described in the preferred embodiments.

Claims

CLAIMS :

1. A dispenser comprising a first cylinder (11), a piston (4) slidable in the first cylinder to vary the volume of an annular pump chamber (13) defined therein, a first tubular member (5,20) integral with the piston and extending outwardly of the first cylinder and through which a discharge passage (316,98) extends, a second tubular member (301,22) constituting an inner wall of the annular pump chamber and defining a bore (14) communicating with a liquid supply means (91) , a valve member (318,31) slidably received in the bore and co-operable in a rest position of the valve member with a valve seat (25) defined by the piston to close the discharge passage, and a stem (314,30) connected to the valve member and extending through the first tubular member, characterised by the second tubular member being integral with the piston and defining an aperture (26) comprising one or more openings communicating between the chamber and the bore and by the valve member being movable relative to the aperture in response to relative movement of the stem and piston between an actuated position in which the chamber communicates with the dispensing channel via the aperture and the rest position in which the chamber communicates with the liquid supply means via said aperture.

2. A dispenser as claimed in claim 1 comprising a second cylinder (12) formed integrally and co-axially with the first cylinder, the second cylinder having a smaller diameter than that of the first cylinder and having an internal surface (409) sealingly engaged by an annular periphery (408) of the second tubular member.

3. A dispenser as claimed in claim 2 wherein the second cylinder comprises a re-entrant tubular section (410) having an outer cylindrical surface sealingly engaged by the annular periphery of the second tubular member.

4. A dispenser as claimed in any of claims 2 and 3 comprising a spring (701) located externally of a body (702) constituted by the first and second cylinders and engaging an actuator (60) mounted on the stem to bias the actuator away from the body.

5. A dispenser as claimed in any of claims 1 to 3 comprising a spring (80) located in the bore and engaging the valve member so as to bias the valve member into the rest position and the stem outwardly of the first cylinder.

6. Apparatus as claimed in any preceding claim comprising an actuator (60) fixedly connected to an end portion (61) of the stem and connection means (63,67) operable between the first tubular member and the actuator such that lost motion is provided between reciprocating movement of the stem and the first tubular member.

7. A dispenser as claimed in claim 6 comprising locking means selectively operable to prevent relative axial movement between the stem and the first tubular member so as to selectively lock the valve member in a position in which the discharge passage is closed.

8. A dispenser as claimed in claim 7 wherein the locking means (708) comprises co-operating key formations of the first tubular member and the actuator whereby the locking means is actuable by rotation of the actuator relative to the first tubular member.

9. A dispenser as claimed in any preceding claim wherein the dispensing channel is defined between an external surface of the stem and an internal surface of the first tubular member.

10. A dispenser as claimed in any of claims 1 to 8 wherein the dispensing channel is defined by a duct extending through the stem and communicating with a radial bore located adjacent to the valve member.