Reciprocating pumps for soaps, pastes and the like

DESCRIPTIVE MEMORY filed in support of a request for

PATENT OF INVENTION formed by: STERLING-WINTHROP GROUP LIMITED for: Suction and fulling distribution pumps.

The present invention relates to suction and pressure pumps for the delivery of fluid substances such as soap preparations, as well as other detergent or toilet preparations, food products and the like in the form of pastes, creams and liquids having different degrees . viscosity. ·

The object of the invention is to provide a reliable pump of simple construction. '

The present invention relates to a suction and pressure distribution pump comprising a cylinder, a piston slidable therein and also able to be moved manually against the action of a spring between an external position vis-à-vis the cylinder. cylinder and an internal position, a tubular sleeve slidably mounted on an inner end of reduced diameter of the piston to move relative to the latter between a first and a second position displaced axially by movement of the piston between its outer position and its inner position to adjust the communication between the space of the cylinder located inside the inner end of the piston, as well as an inlet port and an outlet port provided respectively in the piston, this outlet port leading to an outlet passage extending in the longitudinal direction of the piston, the aforesaid tubular sleeve closing the outlet port when it occupies its first position, while it closes the entrance light when it occupies its second position. .

The tubular sleeve acts as a slide valve mounted on the piston and slidable with respect to both the piston and the cylinder to uncover the inlet and outlet ports in predetermined positions during dispense strokes and piston return. To this end, there is advantageously provided, at the inner end of the piston, a retaining element which engages on one end of the tubular sleeve, the udder

- 3 tone comprising a stop element intended to come into engagement on the other end of the sleeve, in order to determine the first and the second position of the tubular sleeve relative to the piston. Preferably, the tubular sleeve comprises sealing elements such as one or more O-rings creating friction between the tubular sleeve and the wall of the cylinder. In this way, during the sliding of the piston, the tubular sleeve is initially kept stationary relative to the cylinder until the retaining element or the stop element engages therein, the piston and the sleeve moving. then in unison for the remainder of the piston stroke.

The substance to be dispensed is introduced through the inlet lumen into the cylinder space behind the end of the piston. When manual pressure is exerted on the piston from its outward position to initiate a working stroke, the tubular sleeve initially remains stationary in the cylinder and the piston slides in the sleeve until the latter comes into contact with it. the stop element provided on the piston. By the time this position is reached, the tubular sleeve has closed the inlet lumen and opened the outlet lumen. Following contact between the stop element and the tubular sleeve, the latter performs a complementary movement with the piston sliding in the cylinder and, through the rest of the working stroke, the soap is expelled from the cylinder space by the exit port and the longitudinal passage provided in the piston. At the end of the working cours.e, the piston is released and the spring can return it to its external position. The friction again immobilizes the tubular sleeve in the cylinder during the initial part of the return movement of the piston; during this initial movement and while the inlet lumen is still closed, the pressure in the cylinder space drops below atmospheric pressure, so that a certain amount of the substance present

- 4 in the outlet passage is forced back into the cylinder space via the outlet port. This back suction or positive discharge prevents the substance remaining in the outlet passage from dripping out of the end of the latter and thus, it is not necessary to provide a one-way sealing end cap at the outlet. distribution, as is often the case with distributor pumps. Aspiration continues until the piston has made an outward return stroke a distance sufficient to completely close the outlet lumen or open the inlet lumen. Preferably, the outlet lumen and the inlet lumen are axially separated by a distance substantially equal to the axial length of the tubular sleeve so that when one of the lumens is open the other is simultaneously closed. When the inlet lumen is opened, the cylinder space begins to fill with the substance to be dispensed and, at the end of the outward stroke, the elements return to their original position in which the intended retainer element. on the piston engages on the tubular sleeve.

Preferably, the arrangement and the configuration of the tubular sleeve, of the stop element and of the retaining element are such that there is only a point contact during their engagement. In this way, the tubular sleeve is prevented from jamming with the piston and, moreover, the sleeve remains stationary during the initial part of the distribution and return strokes of the piston.

In a preferred embodiment, a manually engaged dispensing head is attached to the outer end of the piston and has a dispensing passage directed downward and communicating with the longitudinal outlet passage formed in the piston. The spring can then be mounted between the distribution head and a flange projecting radially outwards and provided on the cylinder.

The above characteristics and advantages of the present invention, as well as others, will emerge more clearly on reading the following description of a suction and pressure distribution pump according to the present invention, with reference to the accompanying drawings in which: Figure 1 is a longitudinal section of the suction and pressure pump mounted in a soap dispenser; and Figures 2 to 5 are sectional views illustrating the pump respectively under different operating conditions.

Figure 1 shows part of a soap dispenser provided with a dispensing pump according to the present invention. The soap dispenser comprises a reservoir 1 intended to contain a certain quantity of a fluid soap preparation to be dispensed, the drawing showing only the lower part of the wall of this reservoir. A suction and pressure pump 2 is fixed to the wall of the tank by means of screws 3.

The pump 2 comprises a cylinder 4 in which a piston 6 can slide. A flange 5 protruding radially outwards and provided on the cylinder constitutes a means for fixing the pump 2 to the wall of the tank by means of the screws 3 of such that the major part of this pump is located in the tank 1 to be immersed in the soap preparation that this tank contains. A distribution head 8 is rigidly fixed to the outer end of the piston 6, while a return spring 10 mounted between the head 8 and the flange 5 pushes the piston outwards into the outer position or rest position shown. in Figures 1 and 2. A locking screw 12 screwed through the wall of the cylinder engages on an inclined face 14 of the piston 6 in order to prevent the latter from leaving the cylinder.

The inner end 15 of the piston 6 in the cylinder 4 has a reduced diameter compared to that of the rest of the piston and the cylinder 4. A tubular sleeve 16 is slidably mounted on the inner end 15 of reduced diameter. . An O-ring 18 fitted in the sleeve 16 seals against the wall of the cylinder 4. A retainer 20 is attached to the inner end of the piston to prevent sleeve 16 from sliding out of the end of the piston. .

A supply orifice 22 made in the wall of cylinder 4 is in permanent communication with a longitudinal groove 24 made in piston 6. This groove 24 opens onto an annular shoulder 26 formed on the piston at the outer end of the reduced diameter portion 15, while an inlet port 28 consisting of a second longitudinal groove formed in the piston extends the along part 15 between the inner end and a position a short distance from the shoulder 26. The piston 6 occupying its extreme outer position (as shown), a space 29 located at the inner end of the cylinder is filled with fluid soap preparation to be dispensed which has been sucked from the reservoir 1 into the pump through the orifice 22, the groove 24 and inlet lumen 28. Retainer 20 is made such that soap can pass through it or flow freely around it to enter and exit space 29. Arrows 30 in Figure 2 indicate the flow of the soap preparation.

The shoulder 26 acts as a stop element on which the front end 17 of the sleeve 16 engages in order to define an extreme position of the axial displacement of the sleeve 16 relative to the piston 6. The other extreme position is defined. by the inner end of the sleeve 16 on which the retaining element 20 engages. In the illustrated embodiment, the retaining element 20 has the shape of a star washer.

An outlet lumen 32 opening radially on the reduced diameter end 15 of the piston 6 terminates in a longitudinal passage 34 provided in the piston. A distribution passage 36 'directs downwardly in the distribution head 8 communicates with the outer end of the outlet passage 34.

The operation of the pump will now be described with reference to Figures 2 to 5.

Figure 2 shows the piston occupying its extreme outer position in which it is pushed by the spring 10. The locking screw 12 is engaged on the face 14, while the sleeve 16 occupies, relative to the piston 6, a rear position in which it comes into contact with the retaining element 20. The space 29 of the cylinder fills with the soap preparation which has penetrated as indicated by the arrows 30.

In order to dispense a predetermined quantity of the soap preparation, manual pressure is exerted on the dispensing head 8. When the piston 6 begins its inward stroke, following the frictional engagement between the O-ring 18 and the cylinder 4, the sleeve 16 is kept stationary relative to the latter and the piston begins to move through the sleeve 16. During the first part of this movement, the outlet lumen 32 remains closed and the soap begins to be delivered from the space 29 towards the reservoir 1 until the communication is cut by the front end 17 of the sleeve. sealing the inlet lumen 28. At the same time, the outlet lumen 32 begins to open. When the lumen 32 opens, the soap trapped in the space 29 is expelled out of the latter by the exit lumen 32, then it enters the passage 34. The lumen 32 is fully open when the front end 17 of the sleeve engages and comes into contact with the annular shoulder 26 (Figure 3). Then, with the piston continuing to move inward, the sleeve 16 moves in unison with the piston 6. The soap is dispensed out of the passage 36 made in the head 8 (see arrows 38 in figure 4), until the movement of the piston is controlled by the engagement of the head 8 on the outer end of the cylinder 4 .

The head 8 is now released and the spring 10 returns the head 8 and the piston 6 to their outer position. Following the friction with the wall of the cylinder, the sleeve 16 is again held stationary relative to the cylinder 4 during the initial return movement of the piston and, while the inlet lumen 28. is always closed by the sleeve 16 preventing any communication with the groove 24 and the reservoir 1, it creates, in the space 29, a pressure lower than the atmospheric pressure sucking and pushing the soap still in the passages 34 and 36, as shown by arrows 40 in Figure 5. Thanks to this positive delivery of the soap, the latter is prevented from dripping from the dispensing head 8, while it is not necessary to provide, at the end of the dispensing passage 36, a self-dispensing nozzle. - waterproof to one way. This delivery ceases when the piston 6 is returned outward a sufficient distance for the sleeve 16 to discover the front end of the inlet port 28 or for it to have closed the outlet port 32. The axial length of the sleeve 16 must be at least equal to the distance x (figure 5) between the extreme inner edge of the outlet lumen 32 and the extreme outer edge of the inlet lumen 28. The space 29 then begins. to fill again with soap from the reservoir 1. The sleeve 16 engages the retaining element 20, then it moves with the piston 6 until the elements finally assume the positions shown in the figures 1 and 2. .

The sleeve 16 therefore acts in the manner of a slide valve regulating the inlet and outlet ports 28 and 32 in predetermined positions of the distribution and return strokes of the piston 6 and its operation is controlled by the movement of the latter in cylinder 4.

It is desirable that the front end 17 of the sleeve only comes into point contact with the annular shoulder 26 in order to

- 9 to avoid a hydrostatic blockage which would cause the sleeve 16 to move with the piston 6 as soon as the distribution head 8 is released. This point contact can be ensured by providing raised points on the front end 17 of the sleeve or on the face of the shoulder 26. Likewise, it is desirable. that there is only a point contact between the rear end of the sleeve 16 and the retaining element 20.

The length of the piston stroke determines the amount of soap dispensed each time the piston operates and features may be provided to adjust the length of this stroke. Since the face 14 is inclined, it will be understood that the distance over which the locking screw 12 is brought out in the cylinder 4, determines the outer position of the piston and hence the length of its stroke. As a variant, the inclined face 14 can be replaced by a series of steps ensuring a more positive adjustment of the stroke. Another means of adjusting the stroke would be to provide an adjustable stop, for example, a screw passing through the end wall of the cylinder and coming into contact with the end of the piston to determine the latter's inward stroke.

Two longitudinally spaced O-rings 18 may be provided on the sleeve 16 if, as a result of the use of a single O-ring 18 (as shown), this sleeve 16 is found to have a tendency to tilt and stick.

The pump can be made of any suitable material, for example, metal or molded plastic. It is preferable to use materials having low friction characteristics with respect to the surfaces on which the sliding is to take place.