Abstract:
An air brush is shown and described including a replaceable, rotatable, nozzle head including a media port and a needle arrangement. Media contamination of the air brush is limited to the removable nozzle head, thereby making the air brush body free of media contamination. By rotatable mounting of the nozzle head, a variety of media sources are made available, ranging from gravity fed devices such as media top and side cups to suction fed devices such as media jars. The trigger arrangement of the present invention presents an actuator shaft movable longitudinally in response to trigger movement for engagement of the needle of the nozzle head. Mechanical coupling between the air brush body and nozzle head is limited to structural coupling for mounting the nozzle head and an abutment relationship between the actuator shaft and the needle. This allows rotational freedom of movement for the nozzle head relative to the body, and also ease of dismounting by simply separating the nozzle head from the air brush body. The air brush provides both a double-action and single-action trigger for broad versatility in selected modes of use. Overall, the simplified mechanical design and improved operational abilities provide an air brush of great versatility and low maintenance.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates generally to media delivery apparatus, and particularly to air brush construction and media delivery systems.  
           [0002]    An air brush is characterized by a compressed air source and a media source integrated into a handheld device. The compressed air originates from an air compressor delivering compressed air by way of an air hose to the air brush. An intricate set of passageways through the structure of the air brush, including a valve for controlling flow of compressed air, deliver the compressed air to the nozzle. Upon actuation of a spray button, a needle valve releases a flow of media near the outlet of the air brush body while concurrent therewith a source of compressed air is released by valve actuation to provide an air flow around and past the needle valve outlet. The air flow draws media from the needle valve outlet and the media is atomized as it exits the body of the air brush within the air flow. In operation, the user depresses the spray button while moving the device in a desired pattern to produce the atomized spray and desired media coverage.  
           [0003]    Such handheld air brushes are generally complicated mechanical devices including intricate passageways for delivering media and compressed air and requiring various lever and spring assemblies responsive to actuation of the spray button to produce the desired media flow and air stream at the outlet of the air brush. Such mechanical complexity contributes to a generally expensive item requiring significant maintenance and cleaning.  
           [0004]    Because the media flows within the body of the air brush, an air brush requires an intermediate cleaning step between use of different media or media colors. Where media is introduced into the air brush and continuing through to the nozzle outlet, the air brush structure is contaminated with each media or media color used and must be carefully cleaned before a new media or color can be used. In some air brush arrangements, a needle extends along the entire length of the air brush, the needle tip being positioned forward at the nozzle outlet to control media discharge by longitudinal movement of the needle relative to the nozzle outlet. To disassemble such air brush arrangements, the needle is withdrawn from the rear of the air brush, i.e., the tip is pulled through the entire length of the air brush structure. Because the needle tip is necessarily contaminated with media, such procedure contaminates all portions of the air brush having contact with the needle tip during withdrawal of the needle.  
           [0005]    Air brushes are typically used in elaborate art work requiring fine control over media delivery and, in many cases, many different media or many media colors in a single project. Cleaning is particularly burdensome in such use of an air brush because the artist often must apply a great number of colors before the work is complete and for each color change an intermediate cleaning step is required.  
           [0006]    Air brushes come in a variety of basic configurations. In one arrangement, a cup holds a reservoir of media which flows under the influence of gravity out the bottom of the cup and into the air brush structure. In other air brush arrangements, media is held in a jar positioned below the air brush with a tube extending into the body of media within the jar and communicating with media flow passageways of the air brush. As the air flow draws media from the media passageways, media is pulled from the jar and into the air brush. If an artist wishes to use both types of air brushes, the artist must have available two separate air brushes.  
           [0007]    It would, therefore, be desirable for an air brush to be less difficult to use, less complicated in mechanical operation, less expensive, and permit more convenient switching between media or media color.  
         SUMMARY OF THE INVENTION  
         [0008]    A preferred embodiment of the present invention in a first aspect is an air brush comprising a body and a nozzle head. The nozzle head provides a media port and also contains entirely the needle and nozzle arrangement to limit media contamination to the removable nozzle head. The mounting arrangement of the nozzle head relative to body further provides freedom of rotation and, thereby, support for a variety of media sources and user selected orientation during use. The air brush body includes an actuator shaft responsive to trigger movement to engage by abutment the rear end of the needle located entirely within the nozzle head. Relative position between the actuator shaft and the trigger is selectively established to govern the magnitude of media delivered in a media spray relative to a given trigger position.  
           [0009]    The preferred embodiment of the present invention includes a body including a trigger assembly wherein the trigger assembly presents at a head mounting site an actuator shaft movable longitudinally in response to actuation of the trigger. The air brush further includes a nozzle head defining a nozzle conduit, the nozzle conduit providing a nozzle outlet. The nozzle head further includes a coupling structure removably mountable to the body at the head mounting site. The nozzle head includes a needle and spring arrangement, each residing coaxially within the nozzle conduit with the spring biasing the needle away from the nozzle outlet. An abutment end of the needle opposite the nozzle outlet is positioned relative to the actuator of the air brush body whereby the actuator may urge the needle forward toward the nozzle outlet. The nozzle head further includes a media port communicating with the nozzle conduit intermediate of the nozzle outlet and the abutment end of the needle. In accordance with one aspect of the preferred embodiment, rotational mounting of the nozzle head relative to the air brush body allows variation in media sources employed and user selection of device orientation while in use.  
           [0010]    The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation of the invention, together with further advantages and objects thereof, may best be understood by reference to the following description taken with the accompanying drawings wherein like reference characters refer to like elements. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:  
         [0012]    [0012]FIG. 1 is a side view of an air brush according to a preferred embodiment of the present invention in a first mode of operation.  
         [0013]    [0013]FIG. 2 is a side view of the air brush of FIG. 1 partially disassembled and illustrating a second mode of use and adjustment mechanism for trigger operation.  
         [0014]    [0014]FIG. 3 is an exploded sectional side view illustrating individual components of the air brush of FIGS. 1 and 2.  
         [0015]    [0015]FIG. 4 is a sectional view of the air brush taken along lines  4 - 4  of FIG. 3. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]    The preferred embodiment of invention as illustrated in the drawings is an air brush  10  comprising a body  12  and a nozzle head  14 . The nozzle head  14  is removably mountable, i.e., easily mounted and dismounted by the user, relative to the body portion. An alien screw  15  threadably engaging the body  12  and bearing against a portion, described more fully hereafter, of nozzle head  14  secures nozzle head  14  upon the body  12 . Furthermore, and as will be discussed more fully hereafter, media contamination is limited generally to the nozzle head  14 . Generally, media contamination is limited to the nozzle head  14  because media is introduced to the air brush  10  at the nozzle head  14 , rather than the body  12 , and because the nozzle head  14  contains entirely the needle applied to the nozzle outlet. When the nozzle head  14  is removed from body  12 , body  12  is not contaminated and, therefore, requires no cleaning step. Also, because media contamination is limited to the nozzle head  14  and because nozzle head  14  is easily disassembled and serviced, the user generally enjoys reduced effort in servicing and use of air brush  10 .  
         [0017]    With reference to FIG. 1, air brush  10  is shown including a trigger  16  operable in two dimensions, i.e., a double-action trigger. More particularly, trigger  16  is spring biased to an upper or extended position and may be depressed, as indicated by direction arrow  18 , to activate an air flow to the nozzle head  14 . Trigger  16  may also be pivoted, as indicated by double headed arrow  20 , to control a volume of media exiting air brush  10 . Air brush  10  couples to an air hose  22  serving as a source of pressurized air. As may be appreciated, pressing trigger  16  selectively delivers the pressurized air to nozzle head  14  for developing a media spray  24 . As will be discussed more fully hereafter, an adjustment knob  50  establishes a range of movement for the needle within nozzle head  14 , thereby establishing a range of media metering available when operating trigger  16 . The trigger arrangement provided under the present invention serves both a dual-action and a single-action trigger function. Thus, the user may depress trigger  16  and move trigger  16  longitudinally in a double-action fashion, or may simply adjust the knob  50  to a given position, maintain trigger  16  in a given longitudinal position, and depress trigger  16  in a single-action fashion.  
         [0018]    Air brush  10  also couples to a media source, in FIG. 1 illustrated as a jar  26  coupled to nozzle head  14  at a media port  28  thereof. As will be described more fully hereafter, air brush  10  is not limited in the type of media source employed. Media port  28  may be positioned by rotation to receive many types of media source. More particularly, air brush  10  defines a central longitudinal axis  30  and nozzle head  14 , by virtue of its mounting arrangement relative to body  12 , may be rotated about axis  30 . Thus, media port  28  may be moved to a selected position about axis  30 . For example, and as illustrated in FIG. 2, media port  28  may be moved to an upstanding position and receive a media cup  32 . Due to its freedom in rotational orientation fully about axis  30  and relative to body  12 , media port  28  may be coupled to a broad spectrum of media sources. Furthermore, rotation about axis  30  supports a broad spectrum of user selected device orientations when in use. For example, each user may have a preference for device orientation depending on the method of gripping the device when in use and the orientation of the surface to which media is applied. By providing a rotatable nozzle head  14 , the user enjoys a broader range of selectable device orientations for a given media source employed.  
         [0019]    Turning now to FIG. 2, showing nozzle head  14  separated from body  12 , a stepped cylindric mounting site  40  of body  12  receives a matingly compatible stepped cylindric coupling structure  42  of head  14 . Each of mounting site  40  and coupling structure  42  are coaxial relative to axis  30 , thereby permitting rotation of nozzle head  14  about the axis  30 . In this manner, nozzle head  14  may assume a selected rotational position about axis  30  and relative to body  12 .  
         [0020]    Nozzle head  14  is removed from body  12  by sliding coupling structure  42  along axis  30  and out of mounting site  40 . In accordance with the present invention, no mechanical components span the gap between body  12  and nozzle head  14 . As described more fully hereafter, mechanical interaction between body  12  and nozzle head  14  is by abutment between a needle of nozzle head  14  and an actuator shaft of body  12  responsive to trigger  16 . Movement of the needle is in response to actuation of trigger  16 , yet nozzle head  14  may be removed from body  12  by simply sliding coupling structure  42  out of mounting site  40 . Also, body  12  delivers to mounting site  40  pressurized air in response to actuation of trigger  16 . Nozzle head  14  receives the pressurized air at coupling structure  42  for use in developing the media spray  24 .  
         [0021]    [0021]FIG. 2 also illustrates an adjustment knob  50  at the rear of body  12 . A rear handle  51 , including internal threads  51   a  threadably mounts to a collar  52  threadably attached to body  12  just forward of knob  50 , and including external threads  52   a  receiving handle  51 . Handle  51  is a hollow structure receiving therein the knob  50  and providing appropriate support for air brush  10  when held in the hand of the operator thereof, i.e., handle  51  rests against the user&#39;s hand when held in the traditional fashion of an air brush. As described more fully hereafter, adjustment, i.e., turning about axis  30 , of knob  50  establishes a selected position of actuator shaft  142  relative to trigger  16 . This provides adjustment in trigger position relative to needle position. The user of air brush  10  may thereby establish a selected magnitude of media volume delivered in response to a given trigger  16  position.  
         [0022]    [0022]FIG. 3 is a sectional view detailing the internal components of air brush  10 . FIG. 4 is a sectional view taken along lines  4 - 4  of FIG. 3 further illustrating internal components of air brush  10 . In FIGS. 3 and 4, body  12  defines an air valve chamber  60  and a threaded hose mount site  62  whereby hose  22  attaches to body  12  and provides pressurized air to chamber  60 .  
         [0023]    Within chamber  60 , a valve stem  64  resides. A spring  66  captured between a disk  68  of stem  64  and a lower shelf  70  of chamber  60  urges the valve stem  64  toward trigger  16 . Stem  64  extends out of chamber  60  and supports a pivot pin  16   a . The upward extending portion of stem  64  finds lateral support in the apertures  71  of body  12  through which stem  64  passes. As may be appreciated, stem  64  further enjoys longitudinal movement through apertures  71  of body  12 .  
         [0024]    As trigger  16  is depressed, stem  64  is driven downward, in the view of FIG. 3, to allow air to escape from chamber  60  and into air conduit  74  of body  12 . In its normally biased position, disk  68  bears against an O-ring  76  and blocks a flow of pressurized air from entering conduit  74 . As trigger  16  is depressed, however, stem  64  moves against spring  66  and disables the seal provided by O-ring  76  to allow escape of pressurized air from chamber  60  into conduit  74 . Conduit  74  terminates at the mounting site  40  of body  12 . In this manner, pressurized air may be selectively provided to mounting site  40  by depressing trigger  16 . As explained more fully hereafter, pressurized air delivered to mounting site  40  is communicated to coupling structure  42  and then onto the nozzle of air brush  10 .  
         [0025]    Nozzle head  14  includes an air conduit  80  communicating pressurized air from the coupling structure  42  to a nozzle mounting site  82 . Thus, pressurized air is selectively delivered to nozzle mounting site  82  by operation of trigger  16 , i.e., by depressing trigger  16 . The stepped cylindric shape of coupling structure  42  and mounting site  40  facilitates transmission of pressurized air from body  12  to nozzle head  14 . In particular, mounting structure  42  includes a large diameter portion  42   a , an intermediate diameter portion  42   b , and a least diameter portion  42   c . Similarly, mounting site  40  includes a largest diameter portion  40   a , an intermediate diameter portion  40   b , and a least diameter portion  40   c . The diameters of portions  42   a  and  42   c  of mounting structure  42  correspond to the diameters of portions  40   a  and  40   c , respectively, of mounting site  40 . In this manner, nozzle head  14  is securely attached to body  12  by insertion of mounting structure  42  within mounting site  40 , i.e., portion  42   a  being mechanically coupled to portion  40   a  and portion  42   c  being mechanically coupled to portion  40   c . The diameter of portion  42   b , however, is less than the diameter of portion  40   b . Mounting structure  42  and mounting site  40 , when joined, define an air transfer chamber  79  surrounding mounting structure  42 . As may be appreciated, air transfer chamber  79  couples conduit  74  of body  12  and conduit  80  of nozzle head  14 . It is suggested that an O-ring  81  be positioned on the portion  42   c  to establish an air seal preventing air flow into body  12 . In this manner, air entering conduit  74  and delivered to mounting site  40  has but one path to follow, i.e., into conduit  80  for delivery to the nozzle mounting site  82 .  
         [0026]    A nozzle  86 , including external threads  86   a , threadably mounts to internal threads  82   a  of nozzle mounting site  82 . A nozzle cap  88 , including internal threads  88   a , threadably mounts to external thread  82   b  of nozzle mounting site  82 . A needle cap  90 , including internal threads  90   a , threadably mounts to external threads  88   b  of nozzle cap  88 .  
         [0027]    Nozzle head  14  defines a central bore  100  coaxial with axis  30  and terminating at the nozzle mounting site  82 . Nozzle  86  extends bore  100 , including restriction in diameter at the nozzle outlet  86   b . Within bore  100  and nozzle  86  rests a needle  102  providing at its tip in conjunction with the restricted diameter of bore  100  a media valve operable by longitudinal movement of needle  102 . Media port  28  defines a media conduit  104  communicating with a forward portion  100   a  of bore  100 . The rear portion  100   b  of bore  100  is of slightly greater diameter and carries therein a spring  110  and an O-ring  112 , each surrounding needle  102 . O-ring  112  resides at a forward end of bore portion  100   b  and sealably receives the shaft of needle  102 . Media introduced into forward bore portion  10   a  by way of media port  28  does not flow rearward into rear bore portion  100   b . Needle  102  further includes an abutment  102   a  of greater diameter than the shaft of needle  102  and only slightly smaller in diameter than the rear bore portion  100   b . Thus, spring  110  is captured between abutment  102   a  of needle  102  and O-ring  112  at the forward end of conduit portion  100   b . Needle  102  is thereby spring biased away from nozzle  86 , but may be urged toward nozzle  86  by, as will be explained more fully hereafter, an actuator shaft of body  12  driven forward into abutment  102   a  of needle  102 .  
         [0028]    With pressurized air delivered at the periphery of nozzle  86 , i.e., at the outlet of conduit  80 , and provided an escape route around nozzle  86  and out air outlet  88   c  of nozzle cap  88  will draw media from nozzle  86  so long as needle  102  allows flow of media therefrom. As previously described, needle  102  is positioned longitudinally by spring  110  and by engaging abutment  102   a  to move needle  102  toward nozzle  86 .  
         [0029]    Mechanical coupling between trigger  16  and needle  102 , i.e., to establish a position for needle  102  relative to nozzle  86 , is provided by an adjustment mechanism  140 . Adjustment mechanism  140  includes the above noted adjustment knob  50 . Adjustment mechanism  140  further includes an actuator shaft  142  extending from knob  50 , a trigger engagement block  144 , and the mounting collar  52 . Mounting collar  52  includes rearward external threads  52   a  receiving handle  51  and forward external threads  52   b  threadably engaging internal threads  148  of body  12 . Actuator shaft  142  carries at its rear end the adjustment knob  50 , and at its forward end an actuator tip  152 . Actuator shaft  142  lies coaxial relative to axis  30  and, under the influence of trigger  16 , may be moved into engagement with abutment  102   a  of needle  102  whereby needle  102  may be positioned by operation of trigger  16 . Along the length of actuator shaft  142  external threads  142   a  receive threadably thereon the trigger engagement block  144 . More particularly, trigger engagement block  144  includes a forward portion having a rounded front face  144   a  and flats  144   b  on each side thereof. A trigger chamber  160  of body  12  slidably receives block  144 , and includes surfaces  160   a  and  160   b  engaging flats  144   b  to restrict rotation of block  144  about axis  30 . Block  144  further includes a rearward extending cylindric portion  144   c  including internal threads  144   d  threadably receiving threads  142   a  of shaft  142 .  
         [0030]    In this manner, rotation of knob  150  establishes a given longitudinal position of shaft  142  relative to block  144 . Furthermore, the actuator tip  152  extends through and beyond block  144  and into the nozzle head mounting site  40  (see FIG. 2), the magnitude of extension being a function of mechanism  140 . As seen in FIG. 4, trigger  16  includes downward extending legs  16   b  and  16   c , providing an opening in the structure of trigger  16  for passage of shaft  142  therethrough. Also, collar  52  rests coaxially between block  144  and knob  50 , and a spring  162  rests coaxially between collar  52  and block  144 . The assembly of shaft  142 , block  144 , collar  52 , and spring  162  threadably mount to body  12  by threading external threads  52   a  of collar  52  onto internal threads  148  of body  12 . As may be appreciated, adjustment by rotation of knob  50  modifies the position of block  144  along axis  30 . In this manner, the relative position between block  144  and trigger  16  may be selectively established.  
         [0031]    Pivotal movement of trigger  16  rearward engages the rounded front face  144   a  of block  144  to drive block  144  and shaft  142  rearward. This movement allows needle  102  to move rearward under the influence of spring  110  and thereby open a flow of media through nozzle  86 . By adjustment in knob  50 , the magnitude of media delivered for a given position of trigger  16  is selectively established.  
         [0032]    Thus, an improved air brush has been shown and described. The air brush of the present invention allows dismounting of a nozzle head from the air brush body with virtually no contamination of the body. Because the removable nozzle head  14  includes both a media port and a needle, no components of the air brush body  12  need be contaminated with media. By providing an inventory of nozzle heads  14 , a user of air brush  10  can quickly switch between nozzle heads  14  with little or no interruption in work. Furthermore, due to the simplicity of structure and operation of the air brush of the present invention, servicing and maintenance is substantially minimized with resulting improvement in overall operation and life expectancy for the air brush  10 . The air brush  10  provides versatility in receiving different types of media sources. Gravity fed media sources may be used by rotating the nozzle head  14  to provide an upstanding orientation for media port  28 . Other media sources, e.g., jar  26 , requiring suction of media therefrom may be employed by rotating nozzle head  14  to establish a downward orientation for media port  28 . Side mounted media sources may also be used by appropriate rotational positioning of nozzle head  14 .  
         [0033]    The trigger arrangement of air brush  10  provides true double action, true single action or a combination of such trigger actions by a simple mechanical arrangement.  
         [0034]    It will be appreciated that the present invention is not restricted to the particular embodiment that has been described and illustrated, and that variations may be made therein without departing from the scope of the invention as found in the appended claims and equivalents thereof.