1. Field of the Invention
The invention relates to caulking guns of the type which removably hold a tube of caulking material which is discharged through a spout at the end of the tube. More particularly, the invention relates to an improved caulking gun which has a manually operated flow-stopping slide valve which blocks the flow of caulking material within the spout when the valve is moved to a closed position.
2. Description of the Prior Art
There are various types and styles of caulking guns which hold a tube of caulking material in a generally trough-shaped frame. A trigger and handle mechanism is mounted on the rear of the frame for manually moving a plunger forwardly within the tube to force caulking material from the tube through an end spout by forcing the bottom wall of the tube axially along within the tube. The top or front wall of the tube is retained by the end wall of the frame which usually has a slotted opening through which the tube spout or nozzle projects. The plunger may have a series of ratchet teeth formed along a straight shaft portion thereof which are engaged by a spring-biased detent on the trigger mechanism for advancing the plunger within the tube and for retaining the plunger in its forwardmost position upon release of the pressure-applying trigger. Other caulking gun constructions, such as shown in U.S. Pat. No. 4,081,112, use a novel spring arrangement for retaining the plunger in its forward position.
One problem which is common with nearly all known manually actuated caulking guns is the continual discharge of the caulking material from the spout for a short period of time even after the pressure on the trigger mechanism has been released. This discharge will continue until the pressure within the tube of caulking material has equalized. This results in a waste of caulking material and can create a clean-up problem. Also, possible damage can occur to the surrounding area if the caulking is being done in an existing or finished dwelling or location. Even if the pressure which is applied to the plunger is released and the plunger retracted from within the tube of caulking material, a small amount of material will still flow from the end of the spout due to the pressure build-up within the caulking material. Such a manual retraction of the plunger after each application, although reducing the continual discharge problem, is extremely time consuming and difficult.
There is no known caulking gun construction of which I am aware which provides a positive manually actuated flow stopper which blocks the flow of caulking material within the spout in a simple, convenient and economical manner.
USPTO Backgrounds
USPTO Backgrounds