GB2187798A - Material dispenser - Google Patents

Abstract

A dispenser for a tube, 3, of pasty material, comprises a tube housing, 1, and a collar, 6, to retain the shoulders of the tube while permitting the neck or nozzle of the tube to protrude. A piston, 7, is adapted to expel the contents of the tube by turning it outside in. A trigger, 11, actuates drive teeth, 17, to advance the piston by engaging a rack of teeth, 10, on the piston. <IMAGE>

Description

SPECIFICATION Material dispenser This invention concerns a material dispenser, more especially it concerns a dispenser for fluid material pre-packaged in a tube.

Viscous, and more especially tacky materials such as sealants for building and construction use, are difficult to dispense in a reliable and controlled manner. It is known to use a number of different dispensers for pre-packaged materials. For example, the metal skeleton gun is in wide-spread use; a plunger driven by a friction drive mechanism from a trigger bears on a plastic cap in the rear of a stout cardboard cartridge, thus expelling material through a nozzle in the front of the cartridge. The skeleton gun and cartridge exhibit a number of disadvantages, however. The gun and cartridge combination is heavy and requires considerable strength to use, and small-handed people in particular find difficulties. The material may escape around the edge of the cap and may foul the mechanism.Additionally, since the cap cannot be airtight the device is not suitable for hygiene-type materials or those adversely affected by air. The cartridge, which is itself a relatively expensive item, may twist in the gun and may even burst.

The other dispensers for such materials which have had any real form of commercial success are "aerosol" cans and syringe-type dispensers. The "aerosol" pressurised dispensers are very expensive throw-away items and are restricted to use with low to medium viscosity materials. All "aerosol" dispensers are explosive when subjected to heat. Such dispensers are more easy to use than the skeleton gun, although some difficulty may be experienced in tight corners. The lever mechanism used to actuate the flow of material has been known to snap off. The main disadvantages with the syringe-type dispenser are the low capacity and initial awkwardness when the plunger may be too far from the thumb.

As with the skeleton gun, there may be leakage and air access around the plunger.

It is an aim of the present invention to devise a dispenser suitable for dispensing essentially all types of pre-packaged pasty material, not limited significantly to material viscosity and applicable to such materials as sealants, mastics, adhesives, putty and grouts, mortars and cements which do not harden prematurely, lubricants, paints, cosmetics, food pastes including creams and sauces, medical creams and pastes, barrier creams and gels and soaps. Many other materials, whether currently supplied pre-packaged, or not, may be dispensed according to the present invention.

The present invention provides a dispenser comprising a tube housing suitable for a flexible-walled tube of material, a collar portion at a first end of the housing and adapted to retain the shoulders of said tube and provided with an aperture through which the neck of said tube may protrude, a piston having a face and located within the housing and adapted to expel the contents of said tube of material fitted in the housing by turning the tube outside in during advance of the face of the piston towards said first end, and means to advance the piston. Conveniently, the means to advance the piston comprises a rack of teeth mounted on the piston and one or more ratchet teeth adapted to engage the rack and to urge it to advance.The ratchet tooth or teeth may be desirably actuated by a trigger mechanism, and more especially by a trigger on a butt, preferably of such dimensions that at least two fingers of a hand can be used to compress the trigger towards the butt. Other means to advance the piston, for example electrical or pneumatic drive means, may be used, however.

Although the components of the dispenser may be of metal, it is envisaged that all or substantially all the components are conveniently of moulded rigid plastics material, other than possibly some pins, screws or springs.

An efficient and re-usable dispenser may be readily and economically constructed according to the present invention. The collar portion may be integral with the tube housing, but is desirably a separate part detachably connected to the housing, for example a screw-on collar, enabling the tube of material to be easily replaced when necessary or desired.

Although the tube may have a flat base, the invention operates successfully with a base of the common pinched type. The tube must be so constructed that it may be turned outside in without tearing or splitting, and may be of suitable metal and/or plastics construction. A preferred tube is of laminated plastics, and tubes of laminated plastics are currently used for certain cosmetics and toothpastes. The neck of the tube may be formed with an integral nozzle, which may be cut open for use and, if necessary, re-sealed with a cap, or a nozzle, may be screwed on. The choice of cap, nozzle, or other closure, may be made according to the intended use of the material.

The neck of the tube protrudes, as has been already stated, through the aperture in the collar portion and there is substantially no danger of the dispenser being soiled by material from the tube, especially since there is no movable cap in the base. It is desirable that the tube should fit the housing closely and it is therefore envisaged that tubes will be sold with dispensers and as replacements. Marketing considerations may result in differing sizes of dispensers according to the invention for different uses, and hence different tube sizes.

The piston of the dispenser is required to have sufficient clearance between the inner walls of the housing and the outermost part of the piston face to permit the tube to be turned outside in without jamming due to crushing. Desirably, the piston has a flat head, and preferably the face of the head is bevelled. The rack of teeth may be formed in part of, or along substantially the whole length of the piston.

Desirably, a latch is provided to engage the teeth of the rack of the preferred construction, effective to prevent the piston slipping back in use. It is also preferred to provide a lever or trigger to release the latch to withdraw the piston for reloading, or to ease the pressure on the tube after a period of use.

The invention will now be described by way of example only, with reference to the accompanying sectional drawing.

The dispenser of the invention has a tube housing 1, moulded in one piece with a butt section, 2. The other butt section is a separate moulding (not shown), suitably affixed by screws, rivets or adhesive to the butt section, 2; such a butt permits the assembly of various components within as described below.

As an alternative, the tube housing and butt may be moulded in two halves with a hinge or pin-type fastening. The tube housing is shown with an unused flexible-walled tube 3, of pasty material. The tube has tapered shoulders, 4, and a tapered nozzle, 5, screwed on to a threaded neck of the tube (not separately shown). The tube is retained within the tube housing by a collar, 6, screwed on to a threaded portion of the housing. A piston, 7, having a flat bevelled head, 8, is slidably located between bearing lips, 9. The piston carries a rack of teeth, 10 (part of the rack only is shown), moulded along its length. A drive trigger, 11, is pivotably mounted on a pivot, 12, moulded in the butt section, and has a lever face, 13.The lever face 13, contacts a corresponding face, 14, on a drive part, 15, which slides between guides, 16, and carries teeth, 17, engageable with the rack teeth on the piston. A latch, 18, has a flexible strip pivotally mounted on the butt section at 19, and has a latch tooth, 20. The base of the latch tooth is attached to a return spring, 21, which is attached at its other end to the drive part 15. The return spring urges the drive part to return to a rearward position after it has been advanced by compressing the drive trigger. A latch release trigger, 22, also pivoted on pivot 12, has a lip, 23, bearing on the end of the latch.

In use, compression of the drive trigger advances the drive part 1 5 which drives the piston into contact with the tube 3. The tube is turned outside in, expelling its contents through the nozzle. As the rack of teeth on the piston is advanced, the latch tooth 20 jumps successive rack teeth and prevents the piston from being forced back by the reaction from the compressed tube. Release of the drive trigger causes the return spring to draw the drive teeth over the sloping teeth of the rack and to return the drive trigger to its uncompressed position. Hence, material can be easily expelled from the nozzle by successive compressions of the drive trigger. At the end of a desired period of use, operation of the latch release trigger distorts the latch and thereby withdraws the latch tooth from contact with the rack, permitting backward movement of the piston.

Claims (10)

1. A dispenser comprising a tube housing suitable for a flexible-walled tube of material, a collar portion at a first end of the housing and adapted to retain the shoulders of said tube and provided with an aperture through which the neck of said tube may protrude, a piston having a face and located within the housing and adapted to expel the contents of said tube of material fitted in the housing by turning the tube outside in during advance of the face of the piston towards said first end, and means to advance the piston.

2. A dispenser according to claim 1, wherein the means to advance the piston comprise a rack of teeth mounted on the piston, and one or more ratchet teeth adapted to engage the rack and to urge the piston to advance.

3. A dispenser according to claim 2, wherein the ratchet tooth or teeth are actuated by a trigger mechanism.

4. A dispenser according to claim 3, wherein the trigger mechanism comprises a trigger on a butt, the trigger being manually compressible.

5. A dispenser according to any one of the preceding claims, comprising a flexible-walled tube of material adapted to be turned outside in by the advance of the piston.

6. A dispenser according to claim 5, wherein the tube is formed with an integral nozzle on the neck or the neck has a thread by means of which a nozzle or a cap may be screwed on.

7. A dispenser according to any one of the preceding claims, wherein the piston face is flat with a bevelled edge.

8. A dispenser according to claim 2 or any claim dependent thereon, comprising also a latch to engage the teeth of the rack which latch is effective to prevent undesired backward movement of the piston.

9. A dispenser according to claim 8, wherein the latch has means for release.

10. A dispenser according to claim 1, substantially as herein described.