Abstract:
An air spray device includes a barrel with a passage therein, a valve body disposed in the passage and actuated to move to permit fluid communication between an inlet and an outlet of the passage, spray tube with a first tube portion connected to the outlet, and a second tube portion telescopically fitted in the first tube portion, and a nozzle portion which is disposed outwardly of the second tube portion to generate a compressed air stream for removing dust from an object. Retaining members are disposed in the spray tube for retaining the spray tube in one of stretched and retracted positions. By the telescopic spray tube, the dust to be removed will not fly over the user, and the air spray device is convenient to store.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an air spray device, more particularly to an air spray device with a telescopic spray tube that is convenient to use and store. 
     2. Description of the Related Art 
     Referring to FIG. 1, a conventional air spray device is shown to include a barrel  1  with a passage  102  which has an inlet  103  and an outlet  104 , a valve body  3  which is disposed in the passage  102  between the inlet  103  and the outlet  104  and which has upper and lower O-rings  302  and an annular groove  301 , an actuator  5  which is pivotally disposed on the barrel  1  via a pivot pin  4  to actuate the valve body  3  so as to align the annular groove  301  with the inlet  103  and the outlet  104  in order to permit compressed air from the inlet  103  to flow through the outlet  104  and to spray out from a spray tube  6  that is connected to the outlet  104  so as to remove dust on an object for cleaning purposes, and a biasing member  2  which can bias the valve body  3  to align one of the upper and lower O-rings  302  with the inlet  103  and the outlet  104  to interrupt the fluid communication therebetween. 
     Since the length of the spray tube  6  is fixed, dust to be removed from the object may fly over the user during operation. This is particularly undesirable when the air spray device is applied in conjunction with a painting and coating device. In addition, after use, some painting and coating material may be left in the nozzle portion  61 , thereby resulting in inconvenient cleaning thereof. Moreover, numerous air spray devices are required for operating with different materials of painting, thereby resulting in inconvenience during usage. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide an air spray device in which a spray tube has a plurality of tube portions telescopically fitted over each other so as to be stretchable and retractable for added convenience during storage and use. 
     According to this invention, the air spray device comprises a barrel with an inner surrounding wall to define a passage which has an inlet and an outlet downstream of the inlet. A controlling member includes a valve body which is disposed in the passage between the inlet and the outlet, and a stem portion which has an inner end engaging the valve body and an outer end extending from the inner end and transversely and outwardly of the inner surrounding wall so as to be actuated to move the valve body to permit fluid communication between the inlet and the outlet. A biasing member is disposed to bias the valve body to interrupt the fluid communication between the inlet and the outlet. An actuator is disposed on the barrel to actuate the outer end of the stem portion to move the valve body against a biasing action of the biasing member. A spray tube includes first and second tube portions. The first tube portion has a first proximate end which is connected to and which is in fluid communication with the outlet, a first distal end opposite to the first proximate end in a longitudinal direction and downstream of the first proximate end, and a first intermediate tubular portion interposed between the first proximate and distal ends. The first intermediate tubular portion includes a first outer tubular wall surface, and a first inner tubular wall surface which defines a first conduit opposite to the first outer tubular wall surface radially and disposed between and communicating with the first proximate and distal ends. The second tube portion has a second proximate end which is inserted into the first conduit, a second distal end which is disposed opposite to the second proximate end in the longitudinal direction and downstream of the second proximate end and which extends outwardly of the first distal end, and a second intermediate tubular portion which is interposed between the second proximate and distal ends. The second intermediate tubular portion includes a second outer tubular wall surface to be telescopically fitted in the first conduit in the longitudinal direction and to be slidable between a stretched position, where the second proximate end is close to the first distal end, and a retracted position, where the second proximate end is close to the first proximate end, and a second inner tubular wall surface opposite to the second outer tubular wall surface radially and defining a second conduit that is in fluid communication with the first conduit. A nozzle portion is disposed outwardly of the second distal end and distal to the second proximate end, and is fluidly communicated with the second conduit. A first retaining member is disposed on and extends radially and inwardly from the first inner tubular wall surface proximate to the first proximate end so as to arrest further movement of the second proximate end toward the first proximate end in the retracted position. A second retaining member is disposed between the first distal end and the second outer tubular wall surface proximate to the second proximate end to arrest further movement of the second proximate end toward the first distal end in the stretched position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments of the invention, with reference to the accompanying drawings, in which: 
     FIG. 1 is a sectional view of a conventional air spray device; 
     FIG. 2 is an exploded perspective view of a first preferred embodiment of a spray tube of an air spray device according to this invention; 
     FIG. 3 is a sectional view of the first preferred embodiment in a retracted state; 
     FIG. 4 is a sectional view of the first preferred embodiment in a stretched state; 
     FIG. 5 is a sectional view of a second preferred embodiment of this invention in a retracted state; 
     FIG. 6 is a sectional view of the second preferred embodiment in a stretched state; 
     FIG. 7 is a sectional view of a third preferred embodiment of this invention in a retracted state. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Before the present invention is described in greater detail, it should be noted that same reference numerals have been used to denote like elements throughout the specification. 
     Referring to FIGS. 2,  3  and  4 , the first preferred embodiment of the air spray device according to the present invention is shown to comprise a barrel  10 , a biasing member  30 , an actuator  14 , a spray tube  40 , a nozzle portion  50 , and a plurality of retaining members. 
     The barrel  10  has an inner surrounding wall to define a passage  12  which has an inlet  121  and an outlet  122  downstream of the inlet  121 , and a controlling member which includes a valve body  20  disposed in the passage  12  between the inlet  121  and the outlet  122 , and a stem portion  201  which has an inner end that engages the valve body  20  and an outer end that extends from the inner end and transversely and outwardly of the inner surrounding wall so as to be actuated to move the valve body  20  to have an annular groove  25  aligned with the inlet  121  and the outlet  122  to establish fluid communication between the inlet  121  and the outlet  122 . 
     The biasing member  30  is disposed to bias the valve body  20  to interrupt the fluid communication between the inlet  121  and the outlet  122  via upper and lower O-rings  23 ,  24  which are sleeved on the valve body  20  and which are disposed at opposite sides of the annular groove  25 . 
     The actuator  14  is disposed pivotally on the barrel  10  to actuate the outer end of the stem portion  201  to move the valve body  20  against a biasing action of the biasing member  30 . 
     In this embodiment, the spray tube  40  includes first, second and third tube portions  41 ,  42 ,  43 . 
     The first tube portion  41  has a first proximate end  411 , a bushing  48  which is inserted into the first proximate end  411  and which has an externally threaded portion  481  that engages threadedly an internally threaded portion  123  of the outlet  122  and that is in fluid communication with the outlet  122 , an O-ring  413  which is sleeved on the first proximate end  411  to provide an air-tight connection, a first distal end  412  which is disposed opposite to the first proximate end  411  in a longitudinal direction and downstream of the first proximate end  411 , and a first intermediate tubular portion which is interposed between the first proximate and distal ends  411 ,  412 . The first intermediate tubular portion includes a first outer tubular wall surface  414 , and a first inner tubular wall surface  415  which defines a first conduit  416  opposite to the first outer tubular wall surface  415  radially and which is disposed between and which communicates with the first proximate and distal ends  411 ,  412 . 
     The second tube portion  42  has a second proximate end  421  which is inserted into the first conduit  416 , a second distal end  422  which is disposed opposite to the second proximate end  421  in the longitudinal direction and downstream of the second proximate end  421  and which extends outwardly of the first distal end  412 , and a second intermediate tubular portion which is interposed between the second proximate and distal ends  421 ,  422 . The second intermediate tubular portion includes a second outer tubular wall surface  424  of a diameter which is smaller than that of the first inner tubular wall surface  415  so as to be telescopically fitted in the first conduit  416  in the longitudinal direction and to be slidable between a stretched position (as shown in FIG.  4 ), where the second proximate end  421  is close to the first distal end  412 , and a retracted position (as shown in FIG.  3 ), where the second proximate end  421  is close to the first proximate end  411 , and a second inner tubular wall surface  425  which is disposed opposite to the second outer tubular wall surface  424  radially and which defines a second conduit  426  that is in fluid communication with the first conduit  416 . 
     The third tube portion  43  has a third proximate end  431  which is inserted into the second conduit  426 , a third distal end  432  which is disposed opposite to the third proximate end  431  in the longitudinal direction and downstream of the third proximate end  431  and which extends outwardly of the second distal end  422 , and a third intermediate tubular portion which is interposed between the third proximate and distal ends  431 ,  432 . The third intermediate tubular portion includes a third outer tubular wall surface  434  of a diameter which is smaller than that of the second inner tubular wall surface  425  so as to be telescopically fitted in the second conduit  426  in the longitudinal direction, and a third inner tubular wall surface  435  which is disposed opposite to the third outer tubular wall surface  434  radially and which defines a third conduit  436  that is in fluid communication with the second conduit  426 . 
     In addition, each of the first and second distal ends  412 ,  422  has a ring portion  4121 ,  4221  which extends radially and inwardly therefrom to frictionally and slidably contact a respective one of the second and third outer tubular wall surfaces  424 ,  434  so as to confine a respective one of clearances between the first inner and the second outer tubular wall surfaces  415 ,  424 , and between the second inner and the third outer tubular wall surfaces  425 ,  434 . Each of the second and third inner tubular wall surfaces  425 ,  435  defines a pair of insert holes  4211 ,  4311  to communicate with a respective one of the second and third outer tubular wall surfaces  424 ,  434 . 
     The nozzle portion  50  is disposed on the third distal end  432  and distal to the third proximate end  431 , and is fluidly communicated with the third conduit  436 . 
     The retaining members includes a first retaining member  482  which is an abutment wall of the bushing  48  in this embodiment, and which extends radially and inwardly from the first inner tubular wall surface  415  proximate to the first proximate end  411  so as to arrest further movement of the second proximate end  421  toward the first proximate end  411  in the retracted position. A second retaining member and a fourth retaining member are disposed between the first distal end  412  and the second outer tubular wall surface  424  proximate to the second proximate end  421 , and between the second distal end  422  and the third outer tubular wall surface  434  proximate to the third proximate end  431 , respectively. Each of the second and fourth retaining members includes abutment portions  442 ,  452  of a pair of retaining plates  44 ,  45  which are disposed on and which extend outwardly and radially from the respective one of the second and third outer tubular wall surfaces  424 ,  434  such that the abutment portions  442 ,  452  are accommodated in the respective clearance and are movable relative to the respective one of the first and second inner tubular wall surfaces  415 ,  425  so as to abut against the respective ring portion  4121 ,  4221  in the stretched position, thereby arresting further movement of the second and third proximate ends  421 ,  431  toward the first and second distal ends  412 ,  422 , respectively. Each retaining plate  44 ,  45  is detachably sleeved on the respective one of the second and third outer tubular wall surfaces  424 ,  425 , and further has a connecting end opposite to the abutment portion  442 ,  452  in the longitudinal direction and proximate to the respective one of the second and third proximate ends  421 ,  431 . An insert member  441 ,  451  is formed integrally on the retaining plate  44 ,  45  proximate to the connecting end, and is received in the insert hole  4211 ,  4311 . A third retaining member  4411 ,  4511  is connected integrally to the insert member  441 ,  451 , and extends radially and inwardly of the respective one of the second and third inner tubular wall surfaces  425 ,  435  so as to arrest further movement of the third proximate end  431  toward the second proximate end  421  in the retracted position. 
     In use, the third tube portion  43  is pulled outwardly to abut the abutment portions  452  against the ring portion  4221  so as to permit the second tube portion  42  to be pulled outwardly until the abutment portions  442  abut against the ring portion  4121  to place the spray tube  40  in the stretched position, as shown in FIG.  4 . Thus, the distance between the barrel  10  and an opening  51  of the nozzle portion  50  is lengthened so as to prevent dust on an object from flying over the user during cleaning of the object. 
     When it is desired to retract the spray tube  40  for storing the air spray device, the nozzle portion  50  is forced to move the third tube portion  43  into the second conduit  426  so as to abut the third proximate end  431  against the third retaining member  441  such that the second tube portion  42  is moved inwardly of the first conduit  416  until the second proximate end  421  abuts against the first retaining member  482 . 
     As shown in FIGS. 5 and 6, the second preferred embodiment of the air spray device according to this invention is shown to be substantially similar to the first preferred embodiment in construction. Additionally, two bushings  46 ,  47  are disposed respectively on the second and third tube portions  42 ,  43 . Each bushing  46 ,  47  includes an inner portion  461 ,  471  which is disposed on a respective one of the second and third inner tubular wall surfaces  425 ,  435  proximate to the second and third proximate ends  421 ,  431 , and which has an abutment wall  4611 ,  4711  to serve as the third retaining members, and an annular end  462 ,  472  which extends outwardly and radially of and beyond the respective one of the second and third proximate ends  421 ,  431  so as to frictionally and slidably contact a respective one of the first and second inner tubular wall surfaces  415 ,  425 . A plurality of O-rings  466 ,  464 ,  476 ,  474  are disposed between the annular ends  462 ,  472  and the first and second inner tubular wall surfaces  415 ,  425 , and between the inner portion  461 ,  471  and the second and third inner tubular wall surfaces  425 ,  435  so as to provide air-tight connection therebetween. 
     As shown in FIG. 7, the third preferred embodiment of the air spray device according to this invention is also shown to be substantially similar to the first preferred embodiment in construction. The nozzle portion  50 ′ has an internally threaded portion  52 ′ which engages threadedly and detachably an externally threaded portion of the third distal end  432 ′ of the third tube portion  43 ′ of the spray tube  40 ′. The nozzle portion  50 ′ has an opening  51 ′ downstream of the third conduit  436 ′, and an intake port  53 ′ which is disposed between and which is in fluid communication with the third conduit  436 ′ and the opening  51 ′. Thus, the intake port  53 ′, is adapted to be in fluid communication with a liquid container  60 ′, such as a painting container, to cause the liquid contained therein to be entrained in an air stream which flows from the third conduit  436 ′ and out of the opening  51 ′. 
     After use, the nozzle portion  50 ′ can be detached from the spray tube  40 ′ for convenient cleaning. In addition, the nozzle portion  50 ′ can be changed for operating with different colors of paint. 
     While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.