WO2009158270A2

WO2009158270A2 - Device for dispensing adhesive at high pressure

Info

Publication number: WO2009158270A2
Application number: PCT/US2009/047844
Authority: WO
Inventors: John Thomas Tolson
Original assignee: John Thomas Tolson
Priority date: 2008-06-25
Filing date: 2009-06-18
Publication date: 2009-12-30
Also published as: WO2009158270A3

Abstract

A glue gun for dispensing adhesive at high pressure has a dispensing head block capping an axial end of a tubular, adhesive receiving reservoir and formed with a diametric cylinder with an inlet from the reservoir and an outlet. A working piston is reciprocable along the cylinder between longitudinally spaced adhesive inlet and adhesive outlet ends of the cylinder to dispense adhesive at high pressure. A reservoir cup of a lubricant, anti-setting agent or solvent is mounted on an exterior of the cap block and a small bore passageway extends through the cap block between a location of the cylinder adjacent a rear of the inlet and the reservoir cup to feed the lubricant, anti-setting agent or solvent at a controlled rate to the cylinder wall at least throughout the working stroke of the piston, to prevent the piston jamming.

Description

TITLE OF THE INVENTION DEVICE FOR DISPENSING ADHESIVE AT HIGH PRESSURE

RELATED APPLICATION

Priority is claimed from my US provisional application 6175417, filed June 25, 2008, the disclosure of which is incorporated herein by reference

FIELD OF THE INVENTION

The invention relates to a device for dispensing adhesive and other setting materials at high pressure.

BACKGROUND OF THE INVENTION

My prior U.S. patents 5,928,468 issued 1999; 6,217,581 issued 2001 and, 6,402,758 issued 2002, the disclosures of which are incorporated herein by reference, teach precision injection of adhesive/cement at high pressure into dried out furniture joints and bone structures by using a conventional, high pressure lever/trigger action grease gun which is coupled to a zerk connected to an adaptor comprising a workpiece penetrating hollow, needle, optionally formed with a self tapping thread.

A typical grease gun is marketed under the registered trademark Plews- LubriMatic as part 30-465 by Plews/Edelman of Dixon, Indiana and develops up to 10,000 p.s.i.

As well known to the technician, the gun comprises a cylindrical grease reservoir axially capped by a dispensing head block provided with a diametrical working cylinder bore with longitudinally spaced apart inlet and outlet openings to the reservoir and exterior, respectively. A reciprocable working piston, formed as a solid rod is manually urged by the lever forwards along the cylinder bore from a withdrawn position, rearward of the inlet, to the outlet to dispense grease under pressure from the reservoir to the outlet.

However, when such conventional grease gun is used to dispense setting materials such as adhesive/cement or paint, when there is a pause in use and the piston is stationary in the working cylinder, especially when returned to the withdrawn position, there can be a tendency for any residual material in the bore to set, preventing or at least hindering, smooth reciprocation of the piston in the cylinder.

SUMMARY OF THE INVENTION

An object of the invention is to reduce or obviate risk of such uneven piston movement or jamming.

According to the invention, means are provided for feeding a lubricant, anti- setting agent or solvent at a controlled rate to the cylinder piston bore at least throughout the working stroke of the piston to prevent the piston jamming.

The ant-setting agent may simply be a solvent for the dispensed material. For example, where the dispensed material is a water soluble adhesive, the anti-setting agent is water. A water based paint would thinned by water and an oil based paint by an oil thinner such as turpentine. An epoxy would require an epoxy diluent. The solvent will function as an anti-setting agent.

Preferably, the feed means comprises a small passageway extending through the cap block between a location of the cylinder bore adjacent a rear of the inlet and a reservoir cup of agent mounted on the cap block exterior. As the agent is fed at a controlled rate to the cylinder bore at a location immediately behind the inlet and the piston is a sliding fit in the cylinder bore, the agent does not mix to any deleterious extent with the material dispensed by the gun while continuing to effectively lubricate the piston.

Preferably, at least a portion of the bore opening to the exterior surface of the cap block is threaded and the cup is mounted therein as a screw fit.

The well known grease gun may be modified to provide the adhesive/glue dispensing function by the relatively simple and inexpensive additional steps of boring the passageway into the block of an otherwise completed (grease) gun and mounting a suitable cup on the block exterior in operative communication with the passageway.

Alternatively, only relatively minor alterations in the conventional tooling may be required. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic side elevation view of a (left hand) glue gun according to the invention;

Figure 2 is a schematic view of the inner side of the cap block of a (right hand) glue gun with the piston withdrawn, in a rearmost position, uncovering the inlet to permit a new supply of adhesive to enter the inlet, showing the location of the solvent feeding passageway communicating with the cylinder bore; and

DESCRIPTION OF PARTICULAR EMBODIMENT

As shown in Figure 1 , the glue gun comprises a conventional cylindrical adhesive reservoir 1 , closed at an upper end by a cap block 2 carrying a conventional lever operated piston mechanism 3. As shown in figure 2, the interior undersurface portion of the cap block is also conventional having a diametrical bore forming cylinder 4 slidingly receiving working piston 5 and extending from a rear piston entry opening at a rear surface of the block forwards passed a communicating materials inlet 6 to a materials outlet 7 on the upper surface of the block, as shown in fig 1. Conventional filling and pressure relief ports 8 and 9, respectively are also shown, laterally inverted in figures 1 and 2, as they show left hand and right hand operated versions, respectively. Such conventional grease gun is modified by the provision of the feed bore 10, (shown in broken lines), extending through the cap block between a location of the cylinder bore adjacent a rear of the inlet and an outer upper surface of the block where the bore is threaded for mounting a threaded reservoir cup 11 of agent on the cap block exterior. The threaded cup is similar to wick feed oil cups part no.1221 K12-19, but filled with the agent. (Another version is marketed on the website magnetoworks.com.)

The cup 11 contains wicking saturated by the agent which assists in agent retention and feeding of the agent at a controlled rate by capillary attraction. A self closing hinged cover prevents contaminants from entering the cup.

As the agent is fed at a controlled rate, preferably by capillary attraction, to the longitudinal surface of the piston and the cylinder bore at a location immediately behind the inlet and the piston is a sliding fit in the cylinder bore, the agent does not mix to any deleterious extent with the adhesive dispensed by the gun while continuing to effectively lubricate the piston. During advance of the piston in the adhesive dispensing stroke the agent comes into contact with the piston surface for substantially the entire length of the piston which is exposed to adhesive.

A dispensing tube/hose is connected at one end by a fitting to the adhesive dispensing outlet 7 and at the other end to a zerk and adaptor described in my prior patent referred to above.

Claims

1. An adhesive dispenser for dispensing adhesive at high pressure comprising a piston and cylinder assembly in which a working piston is reciprocable along a adhesive receiving cylinder to dispense adhesive therefrom at high pressure and, means for feeding one of a lubricant, anti-setting agent and solvent at a controlled rate to the assembly to prevent the piston jamming.

2. A glue gun for dispensing adhesive at high pressure comprising: a tubular adhesive reservoir; a dispensing head block capping an axial end of the reservoir; a diametrical working cylinder bore formed in the block and having longitudinally spaced apart inlet and outlet openings to the reservoir and to an exterior, respectively; a reciprocable working piston; a trigger/lever linkage operably connected to the piston to manually urge the piston forwards along the cylinder bore from a withdrawn position, rearward of the inlet, to the outlet to dispense adhesive under pressure from the reservoir to the outlet; and means for feeding one of a lubricant, anti-setting agent and solvent at a controlled rate to the cylinder to prevent the piston jamming.

3. A glue gun according to claim 2 in which the piston is formed as a solid rod.

4. A glue gun according to any one of claims 1 to 3 in which said means feeds said one of a lubricant, anti-setting agent and solvent at a controlled rate at least throughout the working stroke of the piston.

5. A glue gun according to claim 4 in which said means comprises: a reservoir cup of one of a lubricant, anti-setting agent and solvent mounted on an exterior of the cap block; and a small bore passageway extending through the cap block between a location of the cylinder adjacent a rear of the inlet and the reservoir cup.

6. A glue gun according to claim 5 in which a portion of the bore opening to the exterior of the cap block is threaded and the cup is correspondingly threaded and mounted therein as a screw fit.

7. A glue gun according to claim 5 in which the reservoir cup contains wicking saturated by said one of a lubricant, anti-setting agent and solvent.