Dispensing – Plural sources – compartment – containers and/or spaced jacket – With discharge assistant for each source
Reexamination Certificate
2000-09-01
2001-09-18
Derakshani, Philippe (Department: 3754)
Dispensing
Plural sources, compartment, containers and/or spaced jacket
With discharge assistant for each source
Reexamination Certificate
active
06290101
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to epoxy guns and, more particularly, to hand-operated epoxy guns of the type employing dual component cartridges and dual ejector pistons for dispensing two component materials.
2. Description of the Background
There are a wide variety of dispensing guns that are used to dispense many types of fluid compositions such as urethane, vinyl, polyester, epoxy and other plastics. Conventional dispensing guns are constructed to provide a barrel to receive a cartridge containing fluid compound which has a dispensing nozzle at one end. These dispensing guns typically have a plunger shaft that is driven by a manual trigger. A piston disk is mounted at the end of the plunger shaft, and hand operation of the trigger moves the plunger shaft and piston through the cartridge to urge compound therefrom. In some cases, such dispensing guns are adapted for use with a double cartridge for dispensing two-component chemical systems such as epoxy and hardener. These are twin-barrel epoxy guns have a pair of plunger shafts commonly driven by a manual trigger mechanism. Some of the two-component chemicals such as epoxy/hardener are of different viscosities which create uneven ejection pressures on the ejection pistons. Additionally, some of these materials are very thick and difficult to eject and require considerable pressure.
For example, U.S. Pat. No. 5,104,005 to Schneider, Jr. et al. issued Apr. 14, 1992 discloses a dual-component gun having a high-pressure ratchet assembly. Also of interest is U.S. Pat. No. 3,767,085 to Cannon et al. which shows a double barrel syringe having a common mixing chamber. Received in the barrels are cartridges containing the two constituents to be mixed, each cartridge having a rear plug which is engaged by a piston. The dual piston rods are urged axially inwardly so that pistons
71
and
72
(
FIG. 1
therein) are urged their full distance through the cartridges.
It is greatly advantageous if these dual-cartridge type guns can accommodate a range of the various-sized dual-compound cartridges that are now available. Otherwise, it would be necessary to purchase multiple guns, one for each cartridge size. A helpful feature in this latter regard is shown in U.S. Pat. No. 5,197,635 to the inventor herein and issued on Mar. 30, 1993. The '635 patent discloses a snap-on piston assembly provided at the ends of the dual plunger shafts (see
FIG. 9
therein). The snap-on piston assembly
450
includes a piston
455
, and a hollow cylindrical base
460
on which piston
455
is mounted. When a plunger shaft is fully inserted within base
460
, a detent ball-bearing
510
releasibly locks it onto the end of the plunger shaft. Many shapes and sizes of pistons
455
may be easily interchanged with this assembly in order to accommodate the various twin epoxy cartridges now available.
While the above-described snap-on piston assembly
450
helps to accommodate different sized cartridges, it also creates a need to secure the various dual cartridges in place despite fixed-size barrels. Often, odd-sized cartridges are used and these must be centered and secured regardless of their size. Otherwise, the cartridges may become loose or uneven and this will cause one side of the tube to extrude more material than the other side. With epoxy or any other two-part compound, the mix ratio is of utmost importance. Centering the cartridges also helps to prevent blowback, a problem of compound extruding rearwardly which in most cases destroys the cartridge and wastes expensive compound. One known attempt at a solution is a spring-biased centering disk that rides the plunger shaft behind the piston. Once the pistons are inserted into the cartridges, the centering disk behind each piston is spring-biased into the rear apertures of the cartridges to thereby keep them centered relative to the plunger shafts. These centering disks are commercially available on certain dispensing guns such as the Cox model PPM-300. Unfortunately, for each piston size, a different centering disk must be kept on hand. In addition, each time a cartridge is exchanged for one of a different size, a different-sized centering disk must be assembled onto the plunger shaft, and this is a tedious and time-consuming process.
It would be greatly advantageous to provide a means for securing and centering various sized cartridges without ever having to touch, adjust, change or remove the centering components for any reason.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a cartridge stabilizing plate for dual barrel dispensers which centering the cartridges on the plunger shafts and thereby helps to maintain the proper mix ratio of epoxy or any other two-part compound, and also helps to prevent blowback (unwanted compound extruding rearwardly).
It is another object to provide a cartridge stabilizing plate as described above that accommodates a range of different piston sizes, thereby avoiding the need to change parts each time that the size of the cartridge(s) changes.
It is a further object to provide a cartridge stabilizing plate as described above that can be economically manufactured and installed onto a dual-barrel dispensing gun at least cost of time and materials.
According to the present invention, the above-described and other objects are accomplished by providing a stabilizing plate for a dual-barrel dispensing gun of the type having a pair of laterally-displaced and adjustable plunger shafts with end-mounted pistons for extruding compound from both cartridges of a variety of sizes of twin cartridge packs. The cartridge stabilizing plate spans both plunger shafts rearwardly of the pistons for engaging both sides of the twin cartridge pack seated in the barrel in order to align the cartridge pack relative to the plunger shafts during use. This feature helps to maintain a proper mix ratio from both sides of said twin cartridge pack. Moreover, the stabilizing plate is capable of accommodating a range of different cartridge sizes, thereby avoiding the need to change parts each time that a different-sized cartridge is used. The stabilizing plate is formed with side-by-side apertures to pass the plunger rods of the dispensing gun, and the apertures may be formed as incremental holes corresponding to the incremental lateral positions of the plunger rods relative to the various standard cartridge sizes. The stabilizing plate is defined by a front face having a series of radial centering channels of increasing diameter, for example, two channels on one side respectively sized to seat 750 ml and 300 ml capacity cartridges of a twin cartridge pack, and three channels on another side respectively sized to seat 300 ml, 150 ml, and 75 ml capacity cartridges. A pair of biasing springs are carried, one on each corresponding plunger shaft behind the stabilizing plate, and a pair of set screws anchor both sides of the stabilizing plate to a corresponding plunger shaft. The stabilizing plate centers the cartridges on the plunger shafts and thereby helps to maintain the proper mix ratio of epoxy or any other two-part compound, and also helps to prevent blow-back (unwanted compound extruding rearwardly). The stabilizing plate can be adapted to accommodate a range of different cartridge sizes, thereby avoiding the need to change parts each time that a different-sized cartridge(s) is used. Moreover, the stabilizing plate can be economically manufactured of molded plastic and installed onto a dual-barrel dispensing gun at minimal additional cost of time and materials.
REFERENCES:
patent: 3767085 (1973-10-01), Cannon et al.
patent: 3933273 (1976-01-01), Cox
patent: 5236105 (1993-08-01), Galex
Bui Thach H
Derakshani Philippe
Law offices of Royal W. Craig
LandOfFree
Cartridge stabilizing plate for dual barrel dispensers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cartridge stabilizing plate for dual barrel dispensers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cartridge stabilizing plate for dual barrel dispensers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2549079