The shaft (with its main bore) is straight and lies along an axis A. The outlet also lies along this axis and so is coaxial, or collinear, with the main bore and shaft. The inlet may also, but need not, be collinear with the main shaft and the outlet.
A lever 30 is connected to the body or to a part of the body (in the illustrated embodiment, it is hinged to the body) and so positioned that movement of the lever operates the seal. The valve assembly may be biased to a closed position (stem out), so that the valve assembly does not open unless the lever presses it in such a way as to open it (e.g., by depressing the stem). The lever may include a valve assembly-contacting portion 31, a hand engagement blade 32 and/or a free end 34. The hand engagement blade may be so sized and/or shaped as to permit comfortable grasping by a human hand. It may have a length sufficiently longer than the length from the pivot to the point of valve contact in the valve assembly-contacting portion to provide a mechanical advantage. Such a mechanical advantage reduces the amount of grasping force a user must exert to maintain the lever in a valve-opening position. The hand engagement blade may be coated in whole or in part with material 23 (not shown).
In a resting state, the lever adopts a first position in which its hand engagement blade is oriented obliquely to axis A. It is typically held in that position by some portion of the valve which is biased to a valve-closed position. When the hand engagement blade is pressed toward the shaft, the lever presses against the valve part (stem 38 in the illustrated embodiment) and causes it to transition to a valve-open position. The force exerted by the lever on the valve contact part must exceed the bias that tends to hold the valve in the closed position (although the force exerted by the user on the hand engagement blade may be less because it is amplified by the mechanical advantage). If the force falls below that of the bias, then the valve transitions back to its resting, closed state. This arrangement is termed a “dead-man trigger” by some because the device will automatically shut off if the user loses his or her grip on the body or otherwise loses control of the device.
A lever guard (i.e., a structure partially surrounding the lever to prevent accidental motion or damage if the airgun is dropped) may be provided.
The body may include a buttress 36. This buttress may provide a surface against which a user may thrust his or her hand to impart force to the nozzle (when using the nozzle for striking, described below). It may also serve to protect the hand and/or to protect the lever.
The body may include a boss 43 at the outlet and/or where the extension connects to the body. The boss may be coated in whole or in part with material 23.
The extension may have a length ranging from negligible (i.e., about zero inches) up to about 20 feet. Exemplary lengths include about 1 foot, about 2 feet, about 3 feet, about 4 feet, about 5 feet, and about 6 feet.
As shown in
The beveled end may have a distal tip 82 that may be used as a chisel to strike and/or break up a surface. The distal tip may come to a sharp edge or itself may be slightly blunted (surface 83); a slight blunt increases the surface area available for striking (and consequently decreases the pressure that may be applied to a surface with any given strike), diminishes the risk of jamming the tip in a crevice, and/or helps prevent deforming the tip when striking it against a hard surface.
The nozzle wall may define one or more side holes 70. These side holes may provide an alternate flow route for fluid passing through the nozzle if the outlet is partially or completely obstructed. Such an alternate route can help ensure that the fluid pressure at the nozzle outlet does not exceed some predetermined level.
The main nozzle bore may include a region 66 of reduced diameter between two regions 68, 69 of larger diameter; such a structure, termed as a “venturi,” may cause a pressure drop in fluid at the downstream large-diameter region. In one embodiment, the reduced diameter region has a diameter of about or exactly 0.4375 inches (1.11125 cm). Region 66 may have the smallest diameter in the flow path through the device (when the valve assembly is open); when it does, it meters flow through the device. When line pressure is regulated at 100 psig, the flow rate may be 150 standard cubic feet per minute.
In the depicted embodiment, side holes 70 roughly coincide with large-diameter region 69. Consequently, the pressure drop created in region 69 during operation helps to draw in air through side holes 70 and increase the total amount of flow delivered to the nozzle outlet.
The airguns described herein may be formed from a variety of materials. The materials may be chosen so as to be suited for the expected use. For example, if an airgun will be used primarily for blowing air and not for striking, then the body, extension, and/or nozzle may be made from a lightweight material such as aluminum, titanium, polymers, plastics, polyvinyl chloride, and/or combinations of these. If an airgun is intended for heavier-duty use, such as striking, then the nozzle and/or other parts may be made from a more durable material, such as steel. An airgun may be formed from two or more separate pieces that are attached to one another (e.g. by welding, soldering, brazing, blending, screwing, bolting, and/or press-fitting), and/or one or more parts of the airgun may be formed as a single integral piece.
The airguns described herein may be employed in a number of ways. For example, they may be used to clear debris from a work area (examples include a piece of industrial machinery, forms for receiving concrete or other materials, and areas in which a material has been broken up and the pieces need to be cleared away) or to break up material to be removed (such as concrete or asphalt). While the embodiments described herein concern airguns, those guns may be modified to become, for example, water guns, oil guns, or guns to spray other fluids. The “other” fluid may be supplied to the main bore or other conduit in communication with the main bore so that it may mix with the pressurized air. In this situation, the gun would emit a mixture of air and the “other” fluid. In some embodiments, the pressurized air may be omitted, so that the gun emits a stream of only the “other” fluid.