Dispensing – With discharge assistant – Container with follower
Reexamination Certificate
1999-12-29
2001-07-17
Kaufman, Joseph A. (Department: 3754)
Dispensing
With discharge assistant
Container with follower
C222S571000
Reexamination Certificate
active
06260737
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to product dispensing devices, and more particularly to devices for manually dispensing viscous liquids.
BACKGROUND OF THE INVENTION
Tools, containers, or devices for dispensing viscous liquid or semi-liquid products or materials are common and. widespread, and find use in many applications, both commercial (end consumer) and industrial. Such product dispensing tools or containers ideally allow the product to be applied in an accurate, mess-free, and waste-free manner.
Conventional small-volume dispensing packages for viscous liquids such as glues, sealants, greases and the like are frequently either disposable syringes or small cartridges. Common sizes range from 10 ml to 80 ml. The syringe-type dispensers commonly use a hand plunger to expel the material contained in a tube through a dispensing outlet or nozzle. Once all the material is dispensed, the entire syringe dispenser is simply thrown away.
In some cases, mechanical hand dispensers are used. In the past, these manual dispensers have been metal or metal/plastic and have incorporated numerous components, such as springs, levers and guides. Such mechanical dispensers are typically designed to be used in conjunction with sealed cartridges containing the product to be dispensed (sealing caulk, adhesive, lubricant, etc.) The cartridges are typically tubes having a sealed dispensing outlet (a conical tip for example) disposed on one end, with the other end being open for receiving a plunger mechanism or the like from the dispenser. Just inside the cartridge's open end is a slidably-sealed, axially-movable piston, disc, or the like. For use, the cartridge is placed in a retaining/dispensing section of the dispensing device, and the plunger is brought into contact with the piston. When a user desires to dispense product, the cartridge's dispensing outlet is unsealed (typically the closed tip of the dispensing outlet is cut off), and the plunger is forced against the piston through whatever actuation mechanism is employed by the dispenser (frequently a trigger/spring/rod mechanism.) This forces the piston axially down the tube and against the product, which in turn is dispensed through the dispensing outlet.
One such dispensing device is found in U.S. Pat. No. 4,509,662, which discloses a caulking gun.
Although the above disclosed caulking gun and similar dispensing devices are still frequently used, they are disadvantageous in many respects. For example, as mentioned above, they contain many separate moving and non-moving parts, and are therefore relatively difficult and expensive to manufacture and assemble. Also, with many designs, even after the desired amount of product is dispensed the plunger mechanism may still exert force against the cartridge piston, thus causing drooling (that is, further unwanted product to be expelled through the dispensing outlet.) This frequently results in wasted product, and may also result in a substantial mess if the user does not anticipate the additional dispensed product.
SUMMARY OF THE INVENTION
Wherefore, it is an object of the present invention to overcome the aforementioned problems and drawbacks associated with the prior art designs.
Another object of the invention is to provide a low cost ergonomic dispenser with a reduced number of parts. As shown below, acceptable function can be achieved with as little as one multi-function drive component which incorporates the functions of a trigger, a pawl, a feature to release the pawl and required return springs.
Another object of the present invention is to provide a low cost dispenser with a reduced number of parts that still has a long useful lifespan.
The presently disclosed invention is a new mechanism for the operation of a manual liquid product dispenser or caulking gun. Generally, the dispenser is intended for dispensing pasty, viscous, semi-fluid products that must be applied with control and accuracy. The device incorporates a unique integral trigger and pawl drive mechanism, in which the drive is activated by a trigger or other actuator. A product dispensing cartridge, syringe or other product container is attached to the front of the dispenser via a cartridge holding mechanism. As the trigger is depressed, the pawl drive mechanism engages and advances a plunger into the product container, contacting and advancing a piston within the cartridge which in turn advances and expels product from a cartridge dispensing outlet. At the completion of the stroke, the trigger is released and the drive mechanism disengages the plunger, the disengagement interaction between the drive mechanism and the plunger causing the latter to move rearwards. A floating gripper, disposed on the plunger, limits the amount of this rearward movement, the effect of which is to decompress the product cartridge and thus prevent drooling after the completion of dispensation.
REFERENCES:
patent: 1672421 (1928-06-01), Negley
patent: 2115591 (1938-04-01), Sherbondy
patent: 2229839 (1941-01-01), Crewe
patent: 2768768 (1956-10-01), Cornell et al.
patent: 3141583 (1964-07-01), Mapel et al.
patent: 4826053 (1989-05-01), Keller
patent: 5992694 (1999-11-01), Keller
Buechner Patrick
Davis & Bujold P.L.L.C.
Kaufman Joseph A.
TAH Industries, Inc.
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