| 摘要 |
1493326 Spray guns G S LEVEY 10 Feb 1975 [19 Feb 1974 18 Nov 1974] 5577/75 Heading B2F An air - less spray gun. (10), Fig. 1 (not shown) comprises a liquid passageway 42, Fig. 2, a pre - orifice assembly 20 including jaw - members 64, 66 radially movable so as to vary the cross . sectional area of a pre - orifice opening 60, and a control knob 126 provided with drive keys 120 axially moving a cylindrical cam member 116 upon manual rotation of the knob 126 so that a bevelled surface 118 of the cam member 116 engages cam surfaces 84a, 86a Fig. 4 of the jaw members. Two leaf springs 68, 70 bias the jaw members apart. The opening 60 is generally circular in cross - section when the jaw members are. in a fully open position, and in the fully closed position, the opening is elliptical, the major axis of the crosssection of the opening being kept parallel to the major axis of an elliptical discharge orifice (136), Fig. 5 (not shown). A spray-tip 40 and an insert 148 engaging flat faces 144 of a pre - orifice spray capsule 58, are press fitted into a spray - tip holder 39 so as to prevent relative rotation between the orifice (136) and the opening 60. In a modified preorifice spray capsule (58'), Fig. 6 (not shown), a disc insert (172) having a through hole (173) is provided instead of a boss (104), Fig. 5 (not shown) the insert being biased in fluidsealing engagement with the jaw members by a spring (174). In a modified pre - orifice spray assembly 200, Fig. 7 the rearward axial movement of a control knob 204 and a knob closure member 206 containing springs 260, 262 causes a corresponding movement of a spray-tip assembly 208 and a pre-orifice capsule 210 relative to an adaptor 202 fixed to the gun, and deforms an elastomeric polyurethane disc 212 to reduce the diameter of a pre-orifice opening 214 owing to a relative sliding movement between a boss 202c of the adaptor and a recess 232. Pins 264 engaged in aligned bores 264a and 264b prevent the rotation of the nozzle assembly 208 relative to the gun. The disc 212 may be frusto-conical and tapering radially away from the dischargeorifice. |
