Patent Publication Number: US-7591435-B1

Title: Safety air guns

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application is a continuation-in-part of U.S. application Ser. No. 29/249,811, filed Oct. 23, 2006, which is hereby incorporated herein by reference. 

   BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1  shows a perspective view of an embodiment of a safety air gun. 
     FIGS. 2-3  show top and bottom plan views, respectively, of the safety air gun embodiment of  FIG. 1 . 
     FIGS. 4-6  show side, front, and back elevation views, respectively, of the safety air gun embodiment depicted in  FIG. 1 . 
     FIG. 7  depicts a safety air gun embodiment held in a user&#39;s hand. 
     FIGS. 8-9  depict prior-art air guns held in a user&#39;s hand. 
     FIG. 10  provides relative coordinate measurements for the contour of a safety air gun body embodiment. 
     FIG. 11  depicts a longitudinal cross-section of an embodiment of a safety air gun. 
     FIG. 12  shows another embodiment of a safety air gun. 
     FIGS. 13-18  illustrate embodiments of levers for a safety air gun. 
     FIG. 19  illustrates a side view of a nozzle. 
     FIG. 20  shows a side view of a valve stem. 
     FIG. 21  illustrates a side view of a valve body. 
     FIG. 22  illustrates a longitudinal cross-section of a valve body. 
     FIG. 23  shows a longitudinal cross-section of an embodiment of a body for a safety air gun after the body has been formed with an inlet bore segment, an outlet bore segment, and a valve bore segment. 
     FIG. 24  depicts a longitudinal cross-section of an embodiment of a body after the intermediate bore segment has been formed and threads have been formed in the inlet bore segment, the outlet bore segment, and the valve bore segment. 

   DETAILED DESCRIPTION 
   Safety air guns (“airguns”) are used to deliver a stream of pressurized air through a nozzle to a target. Exemplary uses include clearing debris, removing dust, and other cleaning tasks. Airguns typically include a handle and a nozzle connected to the handle. The handle receives a pressurized air supply and directs it to the nozzle under the control of a user-operated valve. 
     FIGS. 1-6  show various views of an embodiment of a safety air gun  10 . The safety air gun includes a body  14  having a shape that curves from an inlet end  25  to an outlet end  26 , thereby defining a convex side  27  and a concave side  29 . The body  14  may define a bore extending between the inlet end  25  and the outlet end  26 . A valve-operating lever  12  may be positioned on the convex side  27  of the body  14  and operably coupled to a valve (not shown) that regulates flow through the bore. A valve chamber assembly having valve body  24  and valve stem  20  may be positioned on the convex side of the body  14  such that the valve stem  20  makes contact with lever  12 , such as at strike plate  18 , upon actuation. 
   The convex side  27  and/or the concave side  29  of body  14  may be formed with straight and/or curved surfaces. The body  14  may bulge in a portion adjacent to the inlet end  25 . The body may also have a protuberance  31  extending from the concave side near the outlet end  26 , thereby defining a hook region  38  with part of concave side  29 . The hook region  38  may be of any shape that provides an adequate holding support or resting position for an index finger while the device is in use. For example, the protuberance  31  may have a relatively large width proximate the body, to provide a large contact area for the index finger, and may taper distally to provide a small tip to facilitate hanging up the gun by the tip in a small hole. 
   A pivot pin  28  may extend between the guards and through a hole (element  53  in  FIG. 11 ) in the body, thereby allowing lever  12  to pivot about an axis defined by pivot pin  28  and relative to body  14 . The lever may include grip features, such as ridges  30 , to help improve a user&#39;s grip on the lever. The lever  12  may be curved along its longitudinal length between the attachment position and the more distant of the two ends. The lever curvature may be constant (i.e., the lever forms a sector of a circle), or it may follow other curves, such as a sector of a parabola, ellipse, oval, involute, or a curvature of increasing radius from the attachment position to the more distant of the two ends; the lever may have regions with curvatures differing from one another, may have regions of varying curvature, and/or may have regions with no curvature. 
   Space between the body and the lever may be covered with pinch guards  22  to help prevent pinching a user&#39;s skin between the body and lever when the lever is actuated. Pinch guards  22  may also connect the lever to the body, as shown in the drawings. 
     FIG. 4  provides a side view of the safety air gun embodiment. Dimension S refers to the longitudinal curved length of the lever measured from a distal end to a proximal end of the lever  12 . In some embodiments, dimension S may have a length of at least 4⅛ inches. Such a length may make it possible for a user to grasp and/or press the lever with the entire length of the thumb and thenar eminence (the body of muscle at the base of the thumb), effectively increasing the lever&#39;s mechanical advantage and/or reducing pressure on the user&#39;s tissue by increasing the contact area. Point T is a point at which a perpendicular dropped from the convex surface of the body  14  is tangent to a curve that defines in part the hook region  38 . Dimension B defines a curved length of the concave side extending from point T to outlet end  25  and in some embodiments may be at least 4 inches. In some embodiments, length S may be at least as long as the body length B. Dimension P is measured from the center of the pivot pin  28  to the outlet end  25  and may be in the range of 0 to about 1 inch, such as ¾ inch or less. The pivot may alternatively be positioned at or within similar distances from the outlet end. Positioning the pivot near one of the ends, in combination with providing dimensions S and B as described, helps to ensure that the safety air gun fits across a user&#39;s palm without terminating in the center of the palm. This positioning helps prevent the gun from exerting pressure on the nerves, sheaths, and other structures in the user&#39;s palm that are vulnerable to repetitive-stress injury. It also allows tubing attached to the inlet end (not shown) to drop away downward, thereby minimizing bending moments on the user. The pivot may be so positioned as to be roughly or exactly coaxial with the axis of rotation of the thumb when it moves from an open position into an open-fisted position. 
   Further combining these dimensions with an angle or curvature in the body helps to align the nozzle direction with the user&#39;s forearm axis, thereby permitting use of the device with the wrist in a neutral position.  FIG. 7  depicts the safety air gun embodiment held in a user&#39;s hand. The gun is comfortably nestled in the user&#39;s palm between the third, fourth, and fifth digits and the thenar eminence. The index finger is positioned in the hook region to anchor and stabilize the user&#39;s grip. The thumb and the thenar eminence rest against the lever. The dimensions of the gun are such that when the user&#39;s wrist is in a neutral position relative to the forearm (i.e., neither adducted nor abducted), the nozzle of the gun is aligned with the user&#39;s forearm. Moreover, the slight bulge in the body near the inlet end (hidden by the user&#39;s fingers in  FIG. 7 ) encourages the user to grip the gun body above the bulge instinctively, thereby helping to ensure that the inlet end is not positioned in the center of palm but is rather offset slightly. The bulge may also help to prevent reactive forces from wrenching the gun out of the user&#39;s hand during operation. The bulge, in combination with the other disclosed features, may contribute to encouraging the user to assume an ergonomic grip on the device. Indeed, these features may contribute synergistically to encouraging an ergonomic grip. 
   Prior art guns do not encourage an ergonomic grip and do not achieve the relationships described above. See, for example,  FIGS. 8-9 . The gun shown in  FIG. 8  is actuated by pressing a push-button with the thumb. This requires holding the gun so that its inlet end lies in the middle of the user&#39;s palm. In this position, the gun has a tendency to press against nerves, sheaths, and other structures in the palm and thereby creates discomfort during prolonged use and/or risk of repetitive-stress injury. Also, its nozzle direction is not aligned with the user&#39;s forearm, thereby requiring the user to abduct the hand at the wrist to achieve alignment—a position that is uncomfortable for extended periods. The body of the gun shown in  FIG. 9  does not curve from the inlet end to the outlet end or otherwise angle the inlet end relative to the outlet end. Consequently, when the gun is held in the most comfortable grip with the wrist in a neutral position, the nozzle axis is not aligned with the forearm axis. In this case, the user must adduct the hand at the wrist to compensate—also a position that is uncomfortable for extended periods. Users may try to compensate for these uncomfortable positions and reduce the amount of adduction/abduction required to make the nozzle horizontal by instead pronating the forearm. Pronation, however, creates new disadvantages: in the pronated position, the user cannot use the biceps muscle significantly to support the forearm, and tubing connected to the inlet end points upward and/or outward, creating additional bending moments on the user and increasing the perceived weight of the device. 
     FIG. 10  depicts an outline of a safety air gun body shape and provides relative coordinates (in inches) for points along the convex and concave sides. In various other embodiments, a body&#39;s convex and/or concave sides may follow points within ⅛ inch, 1/10 inch, and/or 1/16 inch of the relative coordinates indicated. 
     FIG. 11  depicts a longitudinal cross-sectional view of a safety air gun embodiment. The body  14  defines a bore extending from the inlet end  25  to the outlet end  26 . The bore may be formed from a series of segments, such as linear segments. In the depicted embodiment, the bore has four linear segments. An inlet bore segment  52  may extend from an opening at the inlet end  25 . A valve bore segment  54  may open to the convex side of the body  14 . The valve bore segment  54  may communicate with the inlet bore segment  52 . An intermediate bore segment  50  may communicate with the valve bore segment  54 , and an outlet bore segment  48  may communicate with the intermediate bore segment  50  and open at the outlet end  26 . The intermediate bore segment  50  may be oriented at an angle such that it can be accessed from outside the body through the valve bore segment opening on the convex side without having to drill or otherwise create any other holes in the body. Such an arrangement facilitates, for example, creating the intermediate bore segment in a single step such as by casting, drilling, or otherwise, as described below. 
   All or portions of the inlet bore segment  52 , the outlet bore segment  48 , and/or the valve bore segment  54  may be threaded to facilitate attachment of pieces to those bores. For example, a hose can be attached to the inlet end by screwing it into the inlet bore segment; nozzle  34  can be attached to the outlet end by screwing it into the outlet bore segment (although it may be attached in other ways, such as press-fitting, or it may be integrally formed with the body); and/or valve body  24  may be attached to the body in the valve bore segment with a similar variety of techniques. 
   The valve body  24  and valve stem  20  may be placed in the valve bore segment  54  to regulate flow through the bore. A spring  44  may be so positioned relative to the valve stem as to bias the valve to a closed position. 
   As discussed above, the body may be curved or angled to permit an ergonomic hold. The nozzle and/or part of the body near the outlet end (and/or outlet bore segment) may be aligned along axis  64 , and the part of the body near the inlet end (and/or inlet bore segment) may be aligned along axis  62 , such that line segments originating from the intersection of the two axes and extending toward the inlet end and the outlet end, respectively, define an included angle α. In the embodiment depicted in  FIG. 11 , included angle α is 130°. In other embodiments, the included angle α may be in the range from 90° to 170°, 90° to 135°, 90° to 130°, no larger than 133°, and/or 110° to 130°. 
   In some embodiments, the lever may be positioned on a side of the body  14  opposite the included angle and operably coupled to the valve. 
   As shown in  FIG. 12 , lever  12  may be attached to the body  14  at an attachment position that is at or adjacent the outlet end  26 . 
   Levers are shown in greater detail in  FIGS. 13-18 . A side view of a lever  12  without an outer coating is shown in  FIG. 13 . The lever may have a constant radius of curvature or may be formed with a flat portion and/or multiple radii. The outer coating material may include rubber, plastic, and/or one or more polymers. The coating may be applied to lever by placing the lever core in a mold and injection-molding the cover around the core. The lever core may be composed of a wide variety of materials, such as metal, steel, and/or plastic. 
   As shown in  FIG. 14 , the lever may be formed with one or more holes. The holes may be formed by casting, molding, drilling, etc. The holes reduce the weight of the lever and/or allow the coating material to fill in the holes during injection molding to strengthen the bond between the outer coating and the lever, preventing slippage of the outer coating from the lever. The size, shape, and positioning of the holes may differ from what is depicted in  FIG. 14 . 
   The width and/or thickness of the lever may taper from one end to the other. 
     FIG. 15  shows a strike plate  18  having an L-shaped extension  15  extending from the lever  12 . The strike place may be located on the concave surface of the lever  12 . A portion of the strike plate  18  may be covered or excluded from the injection-molding mold during the coating process to preserve a section of metal surface to allow a metal to metal contact with the valve stem  20 . 
     FIG. 16  shows a lever with an outer surface coating. Referring to  FIG. 17 , the lever may have a U-shaped cross-section to improve its strength and/or bending resistance. Other cross-sections may be used, such as I-shaped, W-shaped (corrugated), etc. The pinch guard  22  may be covered during the coating process to allow smooth interaction between a metal pinch guard  22  against a metal body  14 . On the convex surface of the lever  12 , a plurality of friction bumps  30  may be disposed with an equal spacing or varying spacing between the bumps to allow better grip by a user.  FIG. 18  shows an isometric view of a finished lever  12  showing an exposed metal strike plate  18 . 
   An exemplary embodiment of a nozzle  34  is illustrated in  FIG. 19 . The nozzle  34  may include a threaded portion along the length to be connected to the body  14 . The nozzle may also include circular or equivalently shaped holes to let the air escape if the safety air gun  10  reaches its maximum capacity and/or to draw surrounding air into the flow. The bore of the nozzle may have a venturi (a region of decreased diameter) to increase flow velocity. A wide variety of nozzles can be used, having varying lengths and conical or frusto-conical tips. 
     FIG. 20  shows an exemplary embodiment of a valve stem  20  with strike end  37  for contacting the strike plate. The strike end may be rounded, as shown, flat, and/or angled to receive the strike plate. O-rings  21  may be seated on the stem to help seal the valve. Edges adjacent to the O-rings  21  may be chamfered or straight instead of rounded as shown in the figure. The straight portion of the valve stem  20  may be so shaped and sized to allow a spring to be disposed for lever actuation. 
   In  FIG. 21 , an exemplary embodiment of a valve body  24  is shown with O-rings  23  and a hexagonally shaped head. A portion of the valve body may be threaded to be screwed into the body  14 . The valve body  24  may retain the valve stem  20  in such a way to allow a controlled longitudinal movement of the valve stem  20  within the valve body  24  during lever actuation.  FIG. 22  is a longitudinal cross-sectional view of the valve body  24  shown in  FIG. 21 . 
   A preferred method of operating a safety air gun  10  may include grasping the safety air gun  10  in a hand so that the index finger of the hand is located in the hook region  38  and having the second, third, and fourth fingers curl around the concave side of the body  14  and the thumb resting against the lever  12 . Lever  12  can be squeezed toward the convex side of the body  14  to permit flow through the body  14 . 
   The body  14  may be formed with the inlet bore segment  52 , the outlet bore segment  48 , and the valve bore segment  54  as shown in  FIG. 23 . The forming may be accomplished in a variety of ways, such as casting, molding, injection molding, forging, electrical discharge machining (EDM), and/or machining, among other methods. After the body is formed, an intermediate bore segment  50  may be formed, such as by drilling, broaching, milling, machining, and/or EDM, among other methods. In the case of drilling, the intermediate bore segment may be drilled by advancing a drill bit through the valve chamber bore  54  at an angle as shown in  FIG. 24 . Alternatively, intermediate bore segment may be formed at the same time as the rest of the body is formed. 
   At least parts of the inlet, outlet, and/or the valve bore segments may be threaded, for example by molding and/or tapping.