This invention relates to threaded retainers. It is disclosed in the context of threaded retainers for retaining air caps, nozzles and the like on the front ends of coating dispensing devices (hereinafter sometimes spray guns). However, it is believed to be useful in other applications as well.
Various types of manual and automatic spray guns are known. There are, for example, the manual spray guns illustrated and described in the following listed U.S. Patents and published applications: 2003/0006322; U.S. Pat. Nos. 6,712,292; 6,698,670; 6,669,112; 6,572,029; 6,460,787; 6,402,058; RE36,378; 6,276,616; 6,189,809; 6,179,223; 5,836,517; 5,829,679; 5,803,313; RE35,769; 5,639,027; 5,618,001; 5,582,350; 5,553,788; 5,400,971; 5,395,054; D349,559; 5,351,887; 5,332,159; 5,332,156; 5,330,108; 5,303,865; 5,299,740; 5,289,974; 5,284,301; 5,284,299; 5,236,129; 5,209,405; 5,209,365; 5,178,330; 5,119,992; 5,118,080; 5,180,104; D325,241; 5,090,623; 5,074,466; 5,064,119; 5,054,687; D318,712; 5,022,590; 4,993,645; 4,934,607; 4,934,603; 4,927,079; 4,911,367; D305,453; D305,452; D305,057; D303,139; 4,844,342; 4,770,117; 4,760,962; 4,759,502; 4,747,546; 4,702,420; 4,613,082; 4,606,501; D287,266; 4,537,357; 4,529,131; 4,513,913; 4,483,483; 4,453,670; 4,437,614; 4,433,812; 4,401,268; 4,361,283; D270,368; D270,367; D270,180; D270,179; RE30,968; 4,331,298; 4,248,386; 4,214,709; 4,174,071; 4,174,070; 4,169,545; 4,165,022; D252,097; 4,133,483; 4,116,364; 4,114,564; 4,105,164; 4,081,904; 4,037,561; 4,030,857; 4,002,777; 4,001,935; 3,990,609; 3,964,683; and, 3,940,061.
It is also known in the art of vehicle fuel tank filler neck caps to provide the caps with clutches permitting the caps to be driven onto the filler necks to predetermined torques. This prevents, among other things, overtightening of the cap onto the filler neck and possible damage to the gasket that seals the cap to the filler neck to prevent the escape of fuel and fuel vapor from the fuel tank.
The disclosures of these references are hereby incorporated herein by reference. The above discussions are not intended to be a representation that a complete search of all relevant art has been made, or that no more pertinent art than that listed exists, or that the listed art is material to patentability. Nor should any such representation be inferred.
One fairly common characteristic of such spray guns is a threaded ring at the front of the spray gun for retaining on the front end of the spray gun an air cap, nozzle, or the like, necessary for the proper operation of the spray gun. A problem associated with such threaded rings is that they can be overtightened. Overtightening may make it difficult to remove the threaded ring if it should be necessary or desirable to remove the air cap, nozzle, or the like which the threaded ring is holding on the spray gun, for example, to clean it, repair it or replace it. Additionally, overtightening the air cap, nozzle, or the like can distort the shape of the air cap, nozzle, or the like. Such distortion can change the physical, spatial relationships of the various orifices provided by such an air cap, nozzle, or the like. Changing the spatial relationships of such orifices can adversely impact the quality of atomization of the coating material being dispensed from such a spray gun. This, in turn, can adversely impact the coating provided by the dispensed coating material.
According to the invention, a retaining ring is provided for a coating material dispenser including a nozzle for the discharge of coating material and a cap having a plurality of orifices arrayed in a spatial orientation with respect to the nozzle to supply a flow of gas or a mixture of gases to aid in dispensing of the coating material from the nozzle. The retaining ring is adapted for retaining the cap on the coating material dispenser with the plurality of orifices in the spatial orientation. The retaining ring includes first and second members. The second member is adapted for coupling to the coating material dispenser. The first member includes a first torque limiting driving member. The second member includes a second torque limiting driven member for engaging the first torque limiting driving member to limit the torque which the second member can apply to the coating material dispenser in response to manipulation of the first member.
Illustratively, the retaining ring comprises an axis about which it is to be rotated to couple the cap to, and uncouple the cap from, the coating material dispenser. The first torque limiting driving member comprises a driving face which extends generally radially and axially of the axis and a camming face which makes an acute angle with the driving face of the first torque limiting driving member.
Illustratively, the second torque limiting driven member comprises a driving face which extends generally radially and axially of the axis and a camming face which makes an acute angle with the driving face of the second torque limiting driven member. The driving faces of the first and second torque limiting driven members engage to drive the retaining ring off the coating material dispenser. The camming faces of the first and second torque limiting driven members engage to drive the retaining ring onto the coating material dispenser.
Illustratively, the first member includes a first portion providing a grip for manipulation of the first member during tightening of the retaining ring onto, and loosening of the retaining ring from, the coating material dispenser, and a second portion providing the first torque limiting driving member. Means are provided for coupling first portion nonrotatably to the second portion.
Illustratively, the retaining ring includes a plurality of first torque limiting driving members.
Illustratively, the retaining ring comprises an axis about which it is to be rotated to couple the cap to, and uncouple the cap from, the coating material dispenser. The plurality of first torque limiting driving members are equally angularly spaced around the axis.
Illustratively, the retaining ring includes a plurality of second torque limiting driven members.
Illustratively, the plurality of second torque limiting driven members are equally angularly spaced around the axis.
Illustratively, the plurality of orifices includes a central orifice and a plurality of orifices surrounding the central orifice.
Illustratively, the coating material dispenser further includes shaping orifices for directing streams of compressed gas or mixture of gases onto the coating material discharged from the nozzle. The shaping orifices are spaced forward from the central orifice and the plurality of orifices surrounding the central orifice.
Illustratively, the shaping orifices communicate with a supply gallery for the compressed gas or mixture of gases to provide compressed gas or mixture of gases for shaping the coating material discharged from the nozzle.
Illustratively, the coating material dispenser includes a valve having a somewhat frustoconically shaped portion and a complementarily configured valve seat adjacent the nozzle.
Illustratively, the coating material dispenser further includes an electrode projecting forward from the nozzle by which coating material dispensed from the nozzle becomes electrically charged.
The invention may best be understood by referring to the following detailed description and accompanying drawings which illustrate the invention. In the drawings:
Referring to
The spray gun includes a valve including a valve body 44 having a somewhat frustoconically shaped front end 46 which cooperates with a complementarily configured valve seat 48 formed by an inner wall of a front portion of the nozzle 24. A needle-like electrode 50 projects forward from valve body 44 and is coupled via its rearward extension through valve body 44 to a terminal of a high-magnitude potential supply 52 by which the particles of coating material become electrically charged as they leave the vicinity of nozzle 24. Spray gun body 20, nozzle 24, air cap 28, and valve body 44 illustratively are constructed from, for example, suitably chemically inert, electrically non-conductive resins or polymers, such as Delrine or Acetron® brand acetal resin or polyetheretherketone. Electrode 50 illustratively is constructed from metal.
Turning now to the details of retaining ring 30, it includes a ratcheting ring or clutch ring 60, a ratcheting plate or clutch plate 62, a housing 64, and a retaining nut 66. The assembled retaining ring 30 is best illustrated in
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In assembly, first ratcheting plate or clutch plate 62 is inserted into housing 64 and tabs 92 into engagement in notches 118 and pawls 98 pointing rearwardly. This fixes ratcheting plate or clutch plate 62 against rotation relative to housing 64. Then ratcheting ring or clutch ring 60 is inserted into housing 64 with pawls 74 pointing forwardly, and pawls 74 are brought into engagement with selected pawls 98 on ratcheting plate or clutch plate 62. The fingers 72 flex at the desired torque to permit relative movement between the camming faces 78 and 102, respectively, of pawls 74 and 98, respectively, to provide the torque limiting tightening feature of retaining ring 30 which reduces the likelihood of overtightening of retaining ring 30 and the consequent distortion of the spatial relationships of the various orifices in the nozzle 24 and air cap 28, or other damage to the front end of spray gun 18. Finally, threads 130 and 132 are engaged and threaded tight to complete the assembly of retaining ring 30. The driving faces 76 and 100 of pawls 74 and 98, respectively, engage when the housing 64 is turned in a direction to disengage retaining ring 30 from threads 82 on spray gun 18.
The retaining ring 30 that limits the amount of torque that may be applied to ratcheting ring or clutch ring 60. This, in turn, limits the force that may be applied to the air cap 28 and/or nozzle 24 by the retaining ring 30. This reduces the likelihood of deformation of the air cap 28 and/or nozzle 24, such as would alter the spatial relationships of the various orifices 26, 32, 34, 38 and the like of the air cap 28 and/or nozzle 24 that might otherwise adversely impact the quality of atomization of the coating material being dispensed from such a spray gun 18. The ratcheting ring or clutch ring 60 and ratcheting plate or clutch plate 62 implement a torque override device that permits the ratcheting ring or clutch ring 60 to slip once the override torque of the ratcheting ring or clutch ring 60 and ratcheting plate or clutch plate 62 is reached when the housing 64/ratcheting plate or clutch plate 62 assembly is turned in a direction to tighten the retaining ring 30 on the front of spray gun 18. The ratcheting ring or clutch ring 60 does not slip when turned in a direction to loosen the retaining ring 30 on the front of spray gun 18.