US2973892A - Feeding arrangement for metal spray gun - Google Patents

Description

March 7, 1961 Filed March 3, 1959 A. F. HEDDE FEEDING ARRANGEMENT FOR METAL SPRAY GUN 2 Sheets-Sheet 1 INVENTOR.

JMOLL March 7, 1961 A. F. HEDDE 2,973,892

FEEDING ARRANGEMENT FOR METAL SPRAY GUN Filed March 3, 1959 2 Sheets-Sheet 2 g 8 /o 5 /b /4l 7 Q 7b 9 w I M E W H0 2 INVENTQR. i MM FEEDING ARRANGEMENT FOR METAL SPRAY GUN Andr F. Hedda, Paris, France, assignor to Societe Nouvelle de Metallisaiion, Paris, France Filed Mar. 3, 1959, Ser. No. 796,950

Claims priority, application France Mar. 4, 1958 2 Claims. (Cl. 226-484) The present invention relates to a feeding arrangement for feeding a rod-shaped material to a pressurefluid operated atomizing gun, and more particularly to a feeding arrangement for feeding a fusible metallic rod or wire to a gun for melting; therein by the application of heat and for spraying of a jet of. molten atomized metal by a stream of gas under pressure.

In conventional guns of the type described above, the wire or rod is fed to a source of heat by two grooved pulleys arranged on substantially parallel respective shafts. Itv is usual to have both pulleys in permanent engagement with a driving motor and to stop feeding of the rod-shaped material to the source of heat in the gun by moving one of the pulleys away from the wire so as to relieve the pressure of the pulleys against the wire. In such an arrangement, one of the pulleys is mounted on a radially movable shaft while the other pulley is mounted on a shaft, the position of which is fixed.

It has been found that with such an arrangement, the friction between the. pulley mounted on the fixedly positioned shaft and the rod-shaped material is sufficient even after removal of the other pulley to cause continued feeding of a certain amount of rod-shaped material after the controls of the spray gun have been set to interrupt spraying. 1

Since the controls for the source of heat in the gun and for the feeding: mechanism are interlocked, an

atent f) 2, ment of the rod with the cooperating atomizing elements of the gun An additional object is a feeding arrangement which is secured against contamination by solid particles in the ambient atmosphere and is-thus not subject to wear by such. particles.

With these and other objects in View, the invention mainly consists in a feeding arrangement of the type generally described having a support, a source of. pressure fluid, two shafts mounted on the support andtwo grooved pulleys respectively mounted on the shafts'in such a manner that respective portions of the grooves of the pulleys face each other so that a rod-likematerial may be clamped between the facing groove portions. The feeding arrangement of the invention furthermore provides means for simultaneously rotating the pulleys, means responsive to the pressure of the pressure fluid for urging each of the shafts to move in a predetermined respective direction relative to the support in such a manner as to urge the facing groove portions of the pulleys toward a line fixed with respect to the support and amount of rod orwire-material is fed into the gun after 7 the source of heat and the stream of. atomizing fluid have been discontinued; This material isnot fused. Itv

is wasted or may interfere with proper functioning of the: gun when operation is resumed.

Feeding of. rod-shaped material to the gun by two cooperating pulleys, one of which is mounted on a fixedly positioned shaft whereas the shaft of the other pulley is radially movable makes it diflicult or even impossible to operate such a gun with fusible materials of different diameter or with. a fusible material the diameter of which varies beyond a very close range of tolerances.

Proper functioning of the gun depends on very precise alignment of the axis of the rod or wire of fusible material with the source of heat and with the stream of atomizing fluid. A feeding arrangement having two pulleys mounted respectively on a fixedly and movably positioned shaft causes a different axial position of the material. fed if the. diameter of the material varies or if. materials of different diameter are employed.

A principal object of the invention is a feeding arrangement for a rodshaped heat fusible material in an atomizing gun or. the like operated by a fluid under pressure in which feeding of the material is started and instantaneously stopped when flow of the pressure fluid is started and. interrupted respectively.

Another object is a feeding arrangement of the type described which. is capable of accommodating rod-shaped material of varying diameter without disturbing the aligntangential to each of the pulleys, and means permanently urging each of the shafts to move in a respective direction opposite to the'predetermined direction.

In its more specific aspects, the invention provides that the shafts carrying the feed pulleys are in permanent engagement with drivingmeans and are each mounted in bearing members acted upon by a fluid under pressure by means of which the gun is operated so that the pulleys are urged against each other by the pressure of the fluid against: the bearing members for clamping the rod shaped material. Upon interruption of the flow of the fluid, the pulleys are each moved away from the rodshaped fusible material by a resilient member permanently urging them apart with a force insuflicient to overcome the force of the fluid under pressure. With such an arrangement, axial movement of the rod-shaped fusible material has been found to stop immediately when the flow of the pressure fluid is interrupted and the pres sure thereof is permitted to dissipate. As soon as the flow of pressure fluid is'restored, the pulleys are urged against each other so as to clamp the fusible material therebetween and to feed it to the gun.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together I with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a side elevational view, partly in section, of a gun of the type described equipped with the feeding arrangement of the invention;

Fig. 2 is a sectional view of a control valve for Operating the inventive feeding arrangement; and

Fig. 3 is a fragmentary sectional view of the gun of V Fig. 1 taken on the line IIIIII.

Referring now to the drawings and more particularly to Fig. 1, there is shown a metal spraying gun for atomizing a rod-shaped fusible material by a stream of gas after it was molten by a flame. The operating parts of the gun are enclosed in a housing 10 from which the spray nozzle 15 projects. Three conduits 16, 17, and 0 18, respectively, supply a combustible fluid, a combuss tion supporting fluid, and an atomizing fluid to the gun.

Examples of suitable fluids are respectively propane, oxygen, and compressed air, but the invention is not limited to any specific fluids, nor is it exclusively applicable'to metal spraying guns in which reaction of a combustible fluid with a combustion supporting fluid is the source of heat for melting a fluidizable rod-shaped material,

Flow of filuids from the conduits 16, 17 and 18 is simultaneously controlled by a multiple rotary control valve in the housing 10 actuated by a lever 19. The multiple valve also includes a valve element controlling admission of the atomizing fluid to the feeding arrangement. An electric motor 20 is arranged in the housing 10 to supply driving energy to the feeding arrangement of the invention. Line current is supplied to the electric motor 20 by a cable 21. The fusible material 30 which may be a metal wire is drawn into the housing 10 by the feeding arrangement of the invention through a guide tube 29.

Fig. 2 illustrates in radial cross section the element of the multiple rotary valve operated by the lever 19 which cooperates with the feeding arrangement of the invention. There is shown a .valve housing 22 formed with three openings therein communicating respectively with the atomizing fluid conduit 16,. a forked conduit 3 and the atmosphere. A rotary valve plug 23 is mounted in the valve housing 22 for rotation by' means of the valve lever 19. The plug 23 has a T-shaped bore 24 which permits'connecting the forked conduit 3 either to the conduit 16 or to the atmosphere.

Fig. 3 which shows a fragmentary sectional view of the gun of Fig. 1, illustrates the feeding arrangement of the invention which is mounted in the housing 10. There is shown a support block 11 secured on the inside of the housing 10 and formed with a cylindrical bore 13. Two plungers 4 and 4' closely fitting the bore 13 are axially movable therein between respective end portions closed by plugs 28 and 28'. A shoulder 13a inwardly projects into the central portion of the bore 13 from the support plug 11. The plungers 4 and 4 are provided with circumferential annular grooves 4a in which packing rings 5 are arranged for preventing leakage of fluid past the plungers from the end portions of the bore 13. The faces of the plungers 4 and 4' arranged opposite each other for abutment against the shoulder 13a are provided with axial recesses 4b in which respective ends of a compression spring 6 are retained so as to urge the plungers 4 and 4 to move away from each other.

The plungers 4 and 4 each have a bore transverse to the axis of the bore 13 and communicating with corresponding bores in the support block 11. The shafts 7a and 7b are arranged in these bores with radial clearance. One respective end of the shafts 7a, 7b is supported in oscillating bearings 2 and 2' mounted in the wall of the housing 10. Respective portions of the shafts spaced from the ends are supported in oscillating bearings 12 and 12 mounted in the respective transverse bores of the plugs 4 and 4.

Grooved pulleys 1a and 1b are fixedly mounted on ends of the shafts 7a and 7b respectively which project outside the support block 11, and are fastened to the shafts by cap nuts 8. Resilient annular seals 14 and 14' are provided between circular surfaces of the pulleys 1a and 1b and the opposite outer surface of the support block 11 to prevent entry of atmospheric contaminants such as solid particles of the material being atomized into the interior of the support block 11.

The shafts 7a and 7b carry meshing gear wheels 9 which are of equal diameter. At least one of the gear wheels 9 is in driving engagement with a mating gear wheel (not shown) which is driven by the electric motor 20.

The two end portions of the bore 13 in the support block 11 communicate with respective ends of the forked conduits 3.

The aforedescribed device operates as follows:

The electric motor 20 is continuously running during working periods of the gun, that is, even when the gun is not in actual operation and the flow of the atomizing fluid is cut off. The shafts 7a and 7b are thus continuously driven by the gears 9 and the pulleys 1a and 1b continuously rotate. As long as the valve control lever 19 is in the inoperative position, the connection between the conduit 16 and the conduit 3 is interrupted by the valve plug 23. When the lever 19 is turned, fluids are permitted to flow through the conduits 16, 17 and 18, and atomizing fluid is admitted by the valve plug 23 through the forked conduit 3 to the end portions of the bore 13 in the support block 11. The pressure of the atomizing fluid urges the plungers 4 and 4 towards each other against the force of the compression spring 6. The pulleys 1a and 1b are thus moved toward each other so that a rod-shaped fusible material positioned between facing portions of the grooves of the pulleys 1a and 1b is clamped therebetween and is fed by the rotating pulleys towards the fusing and atomizing zones of the gun.

When the flow of atomizing fluid through the conduit 16 is interrupted by turning the lever 19, the valve plug 23 is simultaneously rotated into a position in which the forked conduit 3 communicates with the atmosphere and the pressure acting on the plungers 4 and 4 is dissipated. The force of the spring 6 returns both plugs to their positions close to the end portion of the bore 13. Since the position of the wire 30 between the pulleys 1a and 1b is substantially fixed by the guide tube 29, contact between the wire and both pulleys is broken almost instantaneously when the valve is turned and no unmolten material is pushed past the source of heat during interruption of the spraying process. It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of atomizing guns for spraying a fusible material differing from the types described above.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new annd desired to be secured by Letters Patent is:

1. In a feeding arrangement for feeding a rod-shaped material to a pressure-fluid operated atomizing gun and the like, in combination, a support; a source of pressure fluid; cylinder means mounted on said support; two plunger means axially movable toward and away from each other in said cylinder means between end portions thereof; rmilient means interposed between said plunger means to permanently urge the same axially away from each other; means for admitting pressure fluid from said source simultaneously to said end portions of said cylinder means for urging said plunger means axially toward each other; a bearing in each of said plungers; two shafts each mounted in one of said hearings in said plungers; two pulleys respectively mounted on said shafts, each of said pulleys having a peripheral groove, respective portions of the grooves of said pulleys facing each other; means for simultaneously rotating said pulleys, said plunger means being responsive to the pressure of said pressure fluid for urging each of said shafts to move in a predetermined respective direction relative to said support in such a manner as to urge said facing groove portions toward each other and to said resilient means for urging said shafts to move in a respective direction opposite to said predetermined direction, whereby a rodlike material may be clamped between said facing groove portions of said pulleys for feeding during rotation of said pulleys while said pressure is applied to said plunger means.

2. In a feeding arrangement for feeding a rod-shaped material to a pressure fluid operated atomizing gun and thelike, in combination, a support; a source of pressure 76 fluid; two shafts mounted on said support each turnable about the axis thereof and each pivotable about a point located on the axis of the respective shaft adjacent one end thereof; two pulleys respectively fixedly mounted on said shafts adjacent the other ends thereof, each of said pulleys having a peripheral groove facing each other at adjacent portions thereof; a pair of gears respectively fixedly mounted on said shafts adjacent at one end thereof, said gears meshing with each other; means operatively connected to one of said gears for rotating the same to simultaneously rotate said shafts; means responsive to the pressure of said pressure fluid for urging each of said shafts to pivot in a predetermined respective direction about said pivot points relative to the support in such a manner so as to urge said facing groove portions toward each other; and means permanently urg- 15 ing each of said shafts to pivot in a respective direction opposite to said predetermined direction, whereby a rod- References Cited in the file of this patent UNITED STATES PATENTS Hammon Nov. 21, 1939 2,655,066 Siegerist Oct. 13, 1953 2,660,471 Egly et a1. n Nov. 24, 1953 FOREIGN PATENTS 118,627 Germany Mar. 20, 1901

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