Patent Document

TECHNICAL FIELD 
     This invention relates to brushes, and has particular, though not exclusive, application to toothbrushes. 
     BACKGROUND ART 
     Current toothbrushes are commonly one of two different types. The first type requires the user to dispense a quantity of toothpaste from a tube or container onto the bristles of the toothbrush. Such an arrangement requires the provision of separate containers and toothbrushes, and the step of charging the toothbrush with toothpaste from the container prior to use, which can be a messy and time-consuming operation. 
     The second type of toothbrush incorporates its own container of toothpaste, usually in or as the handle of the toothbrush. The container, once empty, can either be refilled or replaced. However, such arrangements suffer from a number of disadvantages, not the least of which is that the overall toothbrush is of relatively complex construction and is therefore expensive to manufacture, operation of the toothbrush usually requiring the actuation and/or manipulation of several different elements within the system. 
     For example it is known to provide a toothbrush provided with a head having one or more openings therein feeding to the bristles, and a flow control mechanism for the toothpaste including a slide member movable longitudinally within the brush relative to the head to open and close the or each opening whereby paste from a container connected to the head can be pumped from the container through the or each opening, when open, onto the bristles. 
     However, the provision of the slide member within the neck and head of the toothbrush imposes severe restrictions on the configuration of the toothbrush, and in particular prevents the provision of an angled, flexible neck as is currently considered desirable for optimum handling purposes. Furthermore, the presence of the slide member necessitates the neck and head of the toothbrush being of a thickness greater than would otherwise be desirable. 
     Furthermore, the openings in the head through which the paste flows to the bristles tend to retain paste therein even after use, and/or are such as to cause water ingress to the head of the toothbrush. Such water ingress can result in bacterial growth within the toothbrush resulting in an unhygienic product. 
     SUMMARY OF THE INVENTION 
     It would be desirable to be able to provide a toothbrush which overcomes the aforementioned disadvantages, and in particular which enables flexibility in design, is simple to operate and is hygienic in use. 
     According to the present invention there is provided a brush comprising a head including a plurality of bristles thereon, at least one outlet in the head feeding to said bristles, a container of paste connected to said head, and actuating means for feeding paste from the container longitudinally of the brush to the head, characterised by, for the or each outlet, a control valve of a flexible plastics material including a diaphragm portion and a nose portion extending from one side of the diaphragm portion, the control valve being positioned within the head with the central axis thereof substantially perpendicular to the direction of flow of paste to the head and having a normal rest position in which the nose portion engages in, to seal, the outlet in the head, the other side of the diaphragm portion of the control valve remote from the nose portion being open to the atmosphere, the arrangement being such that, on operation of the actuating means, paste is fed under pressure from the container to the head to engage with the one side of the diaphragm portion to distort said diaphragm portion whereby the nose portion of the valve is displaced from the outlet and paste is dispensed therethrough, and, on subsequent depressurisation of the paste, the control valve returns, under the influence of its inherent flexibility and atmospheric pressure, to its rest position with the nose portion seating in, to seal, the outlet. 
     It will be appreciated that, with such an arrangement, it is the pressure of the paste itself which serves to open the or each outlet in the head by deforming the or each valve, there being no requirement for any mechanical linkage between the actuating means and the head of the brush. Thus the hollow neck of the brush which conventionally interconnects the container with the head can take a variety of configurations, and may be angled relative to the length of the brush, and flexible relative to the main body of the brush, while the neck and head can be correspondingly reduced in thickness compared with the aforementioned known arrangements. 
     Additionally, operation of the actuating means serves the multipurpose of simultaneously feeding the paste to the head, opening the or each outlet and feeding the paste through the or each outlet to charge the bristles in a single action. 
     In a preferred embodiment of the invention a hollow neck portion extends between the container and the head, the head including a chamber therein in one sidewall of which is formed the or each outlet and in the opposed sidewall of which is mounted the or each control valve. 
     The head of the brush may comprise a cup-shaped end portion into which the neck portion feeds, the base of the end portion forming the opposed sidewall in which the or each control valve is mounted, and a closure portion including a base plate from which project the plurality of bristles, the base plate being a sealing fit in the end portion to define, together with the end portion, the chamber within the head, the base plate forming the one sidewall of the chamber containing the or each outlet. 
     Alternatively the head of the brush may comprise an end portion integral with the neck portion and having the chamber defined therein between one sidewall and an opposed sidewall of the end portion, the neck portion feeding into the chamber, the plurality of bristles projecting from the surface of the end portion containing the one sidewall, the or each outlet being formed in the one sidewall of the end portion and the or each control valve being mounted in the opposed sidewall of the end portion. 
     Conveniently an opening is formed through the opposed sidewall for the or each valve, the radially outer edge regions of the diaphragm portion of the valve being secured at or adjacent the bounding edge of the opening whereby the chamber within the head is sealed from the atmosphere. 
     In one embodiment of the invention the radially outer edge regions of the diaphragm portion of the control valve are molded or welded to the bounding edge of the opening in the opposed sidewall, whereby the control valve is permanently secured to the head. 
     In an alternative embodiment of the invention, the brush includes, for the or each control valve, a ring member which is a snap-fit in the opening to retain the radially outer edge regions of the diaphragm portion therein. 
     Preferably the nose portion of the control valve extends substantially the thickness of the one sidewall of the chamber such that, with the control valve in its normal rest position, the free end of the nose portion is located at or adjacent, and seals against, the end of the outlet remote from the chamber. 
     The control valve is conveniently integrally molded from a soft thermoplastic elastomer or a silicone rubber. 
     Although any suitable pump mechanism may be provided to feed the paste from the container to the head, a preferred brush is provided with actuating means including a manually-operated bellows the interior of which communicates into a reservoir positioned between the container and the head of the brush, the bellows having a normally expanded rest position, compression of the bellows feeding paste under pressure from the reservoir to the head, and subsequent release of the bellows causing the bellows to return to their rest position and to feed paste from the container to the reservoir. 
     Conveniently the actuating means comprise a one-way valve between the container and the reservoir which, on compression of the bellows, is closed whereby flow of paste between the container and the reservoir is prevented, and which, on expansion of the bellows, is opened whereby paste from the container is sucked into the reservoir through the one-way valve. 
     Preferably the bellows, the reservoir and the one-way valve comprise a single-piece moulding for location in the brush with the one-way valve at one end of the reservoir communicating with the container and with the other end of the reservoir communicating with the head of the brush. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded isometric view of a toothbrush according to the invention; 
     FIG. 2 is a longitudinal section through the toothbrush of FIG. 1; 
     FIGS. 3 a  and  3   b  are vertical sections through the head of a toothbrush according to the invention with the control valve in its closed and open positions respectively; 
     FIGS. 4 a  and  4   b  are a plan view and a longitudinal section respectively of the head of a further toothbrush according to the invention, and 
     FIG. 5 is an enlarged detail of the encircled part of the head of FIG. 4 b.    
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 2, the illustrated toothbrush comprises a hollow body member of a molded plastics material indicated generally at  2  and including an open-ended cylindrical portion  4 , a tapering intermediate portion  6 , a narrow neck portion  8  and an upwardly open, cup-shaped end portion  10  into which the neck portion feeds. 
     Located within the cylindrical portion  4  of the body member  2  is a cartridge  12  containing toothpaste, one end  14  of the cartridge  12  being sealed, and the other end of the cartridge  12  incorporating a piston  16  in conventional manner. 
     Actuating means for the toothbrush are indicated generally at  18  and comprise a flexible bellows  20 , the interior of which feeds into an integrally molded reservoir in the form of a tube  22 , the central axis of which is perpendicular to that of the bellows  20 . One end of the tube  22  incorporates a one-way valve  24  and the other end of the tube  22  is open. 
     The actuating means  18  are located in the intermediate portion  6  of the body member  2  with the end of the tube  22  incorporating the one-way valve  24  extending through the one end of the cartridge  12  to interconnect the interior of said cartridge  12  with the interior of the tube  22  by way of said valve  24 , and with the other end of the tube  22  feeding into the hollow neck portion  8  of the body member  2 , and being sealed from the interior of the intermediate portion  6 . 
     The intermediate portion  6  of the body member  2  incorporates a flexible, overmolded button  26  or thumb grip, the undersurface of which engages with the end of the bellows  20  remote from the tube  22  when said bellows  20  are in their normal expanded condition shown in FIGS. 1 and 2. Depression of the button  26  thus moves the bellows  20  into a compressed condition, subsequent release of the button  26  resulting in return of the button  26  and the bellows  22  to their normal positions as illustrated. 
     The base of the end portion  10  of the body member  2  has an aperture  28  formed therethrough in which is mounted a control valve indicated generally at  30 . 
     More particularly, the valve  30 , which is integrally molded from a soft thermoplastic elastomer or a silicone rubber, comprises a circular diaphragm portion  32  from one side of which projects a nose portion  34 . The control valve  30  is secured in the aperture  28  in the base of the end portion  10  as best seen with reference to FIGS. 3 a  and  3   b  with the radially outer regions of the diaphragm portion  32  overmolded on the bounding edge of the aperture  28  and with the nose portion  34  projecting upwardly from the base of the end portion  10 . 
     The brush is completed by a head indicated generally at  36  and including a base plate  38  upstanding from which are a plurality of bristles  40  and in which is formed a tapered outlet  42 , again as best seen in FIGS. 3 a  and  3   b.    
     The head  36  is a sealing snap-fit into the cup-shaped end portion  10  into an assembled operative position in which the outlet  42  is axially aligned with the control valve  30  and in which the nose portion  34  of the valve  30  seats in, to seal, the outlet  42  as shown in FIGS. 2 and 3 a , the base plate  38  and end portion  10  together defining a sealed chamber in the end of the brush. 
     The described toothbrush operates as follows. 
     On compression of the bellows  20  by depression of the button  26 , the volume within the brush between the one-way valve  24 , which prevents flow from left to right as viewed in FIG. 2, and the outlet  42  through the base plate  38 , which is closed by the nose portion  34  of the valve  30 , is pressurised such that fluid therein, be it air or paste, is urged into forcible engagement with the one side of the diaphragm portion  32  to distort said diaphragm portion  32  whereby the nose portion  34  is displaced from the outlet  42  as seen in FIG. 3 b , and the fluid can exit through the outlet  42 . 
     On release of the button  26 , the bellows  20  expand and return to their normal condition shown in FIG. 2, thus reducing the pressure in the aforementioned volume. As soon as the increased pressure is removed from the diaphragm portion  32  of the control valve  30 , the valve  30  immediately returns, by virtue of its inherent resiliency, the effect of atmospheric pressure on the side of the diaphragm portion remote from the nose portion  34 , and the slight draw-back pressure within said volume (see below), to its rest position with the nose portion  34  sealing the outlet  42 . 
     The net result of the bellows  20  returning to its expanded condition is to create a suction effect in the volume between the now closed control valve  30  and the one-way valve  24 , which serves to open the valve  24  whereby paste from the cartridge  12 , which is under atmospheric pressure by way of the piston  16 , is drawn into the tube  22 . This charging of the tube  22  with paste is accompanied by movement of the piston  16  to the left as viewed in FIG. 2, return movement to the right being prevented by one-way means (not shown) in conventional manner. 
     Thus it will be appreciated that initial charging of the toothbrush with paste to fill the volume downstream of the valve  24  is achieved by sequential depression and release of the button  26 . 
     Once this volume is filled, the toothbrush is ready for use. 
     The configuration of the brush is such that on depression of the button  26 , a pre-determined quantity of paste is extruded through the outlet  42  and onto the bristles  40  sufficient for use by the user on release of the button  26 , although additional paste, if required, can be obtained by further depressions of the button  26 . 
     As can be seen in the drawings, and in particular in FIG. 3 a , the nose portion  34  of the valve  30  in the rest position thereof extends substantially to the outer end of the outlet  42  and seals against said outer end in a knife edge manner whereby no previously extruded paste can remain in the outlet  42  after use of the toothbrush, no further paste can be extruded through the outlet  42 , and the ingress of water and dirt through the outlet is prevented. Such an arrangement thus results in an extremely hygienic product and virtually eliminates the possibility of bacteria growing within the brush. 
     FIG. 1 illustrates that the toothbrush comprises a small number of individual parts all of which can be separately molded and robotically assembled. 
     The opening and closing of the outlet  42 , as well as the feeding of paste to and through said outlet  42 , are all achieved as a direct result of pressurisation of the paste, and without the requirement for any mechanical linkage between the actuating means  18  and the outlet  42 . Thus there is no imposition upon the configuration of the hollow neck portion  8  which can be located at a variety of angles relative to the main extent of the body member  2  and can be flexible relative thereto, while the size of the head of the brush can be reduced compared with those containing sliders and the like. 
     FIGS. 4 a ,  4   b  and  5  detail an alternative head in which the bristles  40  are located in a series of pre-formed holes  44  in the upper surface of the end extent  10  of the brush, rather than being part of a separate head for insertion into the end extent  10 . The end extent  10  is bored to provide a chamber therein together with an outlet  42  and a seating for the control valve  30 , the diaphragm portion  32  of the valve  30  being retained in the seating by means of a snap-fit ring  46 . The diaphragm portion  32  may be overmolded on, or separate from, the ring  46 , while the ring  46  may be welded in the seating instead of being a snap-fit therein. Alternatively the ring  46  may be dispensed with and the edge regions of the diaphragm portion  32  welded or otherwise secured to the seating. 
     Clearly the precise construction of the toothbrush may differ from those detailed above without departing from the scope of the invention. The actuation means may be other than bellows operated, and may comprise relatively conventional trigger-operated pumps. It must be appreciated, however, that the described actuating means has the advantage that, in the event that the control valve  30  is inadvertently displaced from the outlet  42  subsequent to use, it will not be possible to recharge the bristles  40  with paste because of the open nature of the volume between the outlet  42  and the valve  24  and the inability to create the necessary suction effect within that volume. Such an arrangement thus prevents the extrusion of excessive amounts of paste that might otherwise occur in the event of failure of the valve  30 . 
     There may be a plurality of outlets  42  feeding to the bristles and a corresponding plurality of valves  30 , which may or may not be interconnected with one another. 
     The diaphragm portions  32  of the valves  30  of FIGS. 1,  2 ,  3   a  and  3   b  may be secured in position other than by overmolding, for example by ultrasonic welding or by being a pop-in friction fit in the associated opening  28 . 
     Other modifications and variations will be apparent to those skilled in the art. 
     The described toothbrushes are inherently user friendly in view of their compact and ergonomic design and their simple operation, while the pre-determined quantity of paste supplied to the bristles by the simple pneumatic actuating system can readily be varied to suit particular requirements. The product is ideally suited to the mass market because of its convenience for day to day use, but is also appropriate for specialised niche markets such as travellers, sportsmen and other related users. 
     Although described in relation to toothbrushes, it will be appreciated that the basic inventive concept has application to other types of brushes provided with containers for paste or other dispensable materials.

Technology Category: 1