Fluid sprinkling – spraying – and diffusing – Flow line or nozzle attached or carried handgrip or handle – Pistol grip type
Reexamination Certificate
2000-11-06
2002-08-13
Evans, Robin O. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Flow line or nozzle attached or carried handgrip or handle
Pistol grip type
C239S525000, C239S527000, C239S414000, C222S145500
Reexamination Certificate
active
06431468
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to dispensers and gun-like dispensing devices used in the foam industry, and more particularly, to a dispenser which is adapted for easy, low-cost mass production manufacture capable of simple, selective actuation to prevent inadvertent or unintended discharge of chemical products.
Over the last couple of decades, there has been an ever-increasing use of polyurethane and like plastic foams for a number of applications. Urethane and related products, including isocyanurates, silicones, phenolics and epoxies, are well known as having a number of desirable characteristics. These include the potential for excellent insulation, compatibility with blowing or foaming agents, reproducibility of chemical characteristics, and excellent chemical and physical properties in the finished product.
Many urethane foams are resistant to degradation by many common solvents, moisture and atmospheric oxidation. Urethanes provide the best combination of heat insulation and physical strength for a given cost. The foam is naturally an adhesive material and bonds well to any number of substrates. In this connection, it can add structural strength to many articles where such strength is an important element. Fire retardance may be achieved easily with available formulations.
Urethane foams, being the reaction product of two individual components, may be varied in chemical composition for a number of purposes. Thus, urethane foams may be formulated so as to provide a finished product which is quite rigid, which is semi-rigid, or which is somewhat flexible and/or elastomeric. Foams of the kind in question may be made with almost exclusively closed cells, or with a desired proportion of open cells.
The types of products with which the instant invention may be used are primarily the two-component and single component closed cell foam types of product used for insulation purposes in building structures as well as open-celled foam types that are commonly used for packaging applications. The components of the foam are passed at high pressures above 40-250 p.s.i. through a hand-held dispenser which serves to meter and mix the components thoroughly in a nozzle from which they are discharged. Chemical components are taken directly to a job site in pre-pressurized cylinders, or shipped in bulk tanks that utilize external pumps or other methods of pressurization. Here, the amount of product required to be dispensed is not so large as to require permanent, expensive equipment, as would be used in a factory. However, the amount of product used is significantly larger than could be accommodated by using small, individual aerosol cans, for example. The individual containers of the components carry from several pounds up to 25 to 50 pounds or more of each component. These tanks are sufficiently portable to be moved about on the job site by one worker, but yet are able to provide sufficient foam to provide several hundred or thousand board feet of coverage.
Hand-held dispensers are used with these smaller chemical supply tanks and such dispensers provide the advantages and characteristics of low cost, reliability, and safety in use.
U.S. Pat. No. 4,676,437, issued Jun. 30, 1997, and assigned to assignee of the present invention discloses a representative construction in such a hand-held dispenser. This dispenser takes the form of a gun with a trigger and a safety for preventing inadvertent discharge of the chemical components from the dispensing gun. Such discharges are unwanted and may be unsafe.
The operating pressures, reactive components and other characteristics of the foam are such that unintended discharge is unwanted. These discharges create waste that clutters up the working area. Often these discharges result from careless or improper handling when users forget or disregard resetting the safety. One disadvantage of the dispenser of the '437 patent is that manipulating the safety from an “on” position to an “off” position is and difficult and sometimes requires the use of two hands to move it. Another disadvantage is that resetting the trigger safety after use of the dispensing gun is not an automatic, or natural step taken in actuating the dispenser. The structure of this safety also makes manipulation from an “off” position to an “on” position easy to forget. Consequently, after the initial use the trigger safety is usually not moved back to an “on” position. In such situations if the gun or dispenser is inadvertently dropped during use, the trigger may be activated by the fall of the gun and foam is inadvertently discharged.
Therefore, there is a demand for a simple-to-use, automatically resetting safety on a foam dispenser which would provide the advantages and characteristics of low cost, safety and reliability in use.
The present invention is therefore directed to a safety mechanism for hand-held foam dispensers that overcomes the aforementioned disadvantages.
SUMMARY OF THE INVENTION
It is therefore a general object of the present invention to provide a foam dispenser which is adapted for easy, low-cost mass production manufacture and which includes an improved safety mechanism that is easy to use and which prevents inadvertent operation of the dispenser.
Another object of the present invention is to provide a safety for a foam dispenser which automatically resets to an “on” position after each use.
Yet another object of the present invention is to provide a safety incorporated into the trigger of a foam dispenser, which may be manipulated to an “off” position simultaneously with the trigger being grasped for effecting the discharge of foam from the dispenser.
Still yet another object of the present invention is to provide a foam dispenser having a safety extending from a grasping surface of a trigger of the dispenser such that a user may manipulate the safety and trigger with one hand in a natural grasping motion in order to actuate the discharge of foam components.
A further object of the present invention is to provide a trigger lock for a fluid dispensing apparatus, wherein apparatus has a handle, a trigger moveably mounted to the apparatus and capable of depression toward the handle to open a passage in the dispenser to permit fluid to pass through, the trigger having a lock member integrated therewith, the lock member having an actuating portion extending lengthwise of the trigger and depressible by a user, whereby depression of the lock member moves the lock member out of interference with a stop surface of the handle, so that the trigger may be fully depressed and the dispenser actuated, and the apparatus including a means for biasing the trigger into an open, non-depressed position.
The present invention accomplishes these and other objects by way of its novel and unique structure. A preferred embodiment of the present invention is characterized by a dispenser for mixing together two reactive foam components to form an expandable foam and dispensing the expandable foam, including a body portion having foam component entrances and a foam mixing chamber. A handle extends from the body portion to facilitate grasping and operation by a user. The flow control valve is located in the body portion for controlling flow of foam components entering the dispenser mixing chamber. A trigger is movably mounted to the body portion in opposition to and spaced apart from the handle. A safety latch, or trigger lock, is provided that prevents unintended operation of the dispenser. The safety is incorporated into the body of the trigger and it extends length wise of the trigger and has a projecting portion that projects past the grasping surface of the trigger. The safety is placed on the trigger so that it may be easily depressed when the trigger is grasped by a user, thereby permitting operation of the trigger. Likewise, when the user is not grasping the trigger, the safety is biased into a safety position so that even if the dispenser were to be dropped, the safety will prevent operation of the dispenser and discharge of the foam component
Brown Daniel P.
Dean Michael C.
Evans Robin O.
Flexible Products Company
Vedder Price Kaufman & Kammholz
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