US3111272A

US3111272A - Fiberglass spray gun

Info

Publication number: US3111272A
Authority: US
Inventors: John W Underdown; John E Ehernberger
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-09-28
Filing date: 1959-09-28
Publication date: 1963-11-19
Anticipated expiration: 1980-11-19

Description

NOV. 1963 J. w. UNDERDOWN ETAL 3,111,272

FIBERGLASS span cum Filed Sept. 28, 1959 2 Sheets-Sheet 1 Fig.

Z t Z John W. Underdown John E. E hernberger INVENTORS 1963 J. w. UNDERDOWN ETAL 3,111,272

FIBERGLASS SPRAY GUN Filed Sept. 28, 1959 2 Sheets-Sheet 2 IIIILI MII John W Underdawn John E. E hernberger INVENTORS BY ma Wzwey FM United States Patent Oil" 3,1 1 1,272 Patented Nov. 19, 1953 3,111,272 FBERGLA SPRAY GUN John W. Underdown, 1844 Linden St, and John E. Ehernberger, 1035 /2 Rose Sh, both of Sydney, Nebr.

Filed Sept. 28, 1959, Ser. No, 842,755 2 Claims. ((31. 239-420 This invention relates to fiberglass spray guns and more particularly to improvements in such equipment making the operation of the gun considerably more economical and clean.

An object of the invention is to provide a spray gun of the type for spraying a mixture of liquid plastic and chopped roving, usually fiberglass, onto a surface of a mold or preform to make various shapes and objects. Specifically, the invention improves the operation of such guns by a chopped roving tube having a discharge end through which the chopped roving is propel-led under air pressure so that the chopped particles are directed into the issuing stream or streams of synthetic resin without relying on gravity feed or the mere attraction of the roving to the issuing jets of resin.

Briefly, the invention is preferably embodied in a gun which has a pair of conventional gun sections arranged at an angle to each other so that the spray of synthetic resin merges to an apex. The frame of the gun is equipped with a chopped roving tube and has an air line or at least, a port through which air under pressure enters the tube. The high pressure air entering the tube cooperates with the walls of the tube to form a low pressure area at the inlet of the tube which is in registry with the roving cutting mechanism of the gun. This sucks the cut roving into the tube and the same air blast propels the roving suspended therein until it merges and meets the streams of synthetic resin from the conventional gun sections.

The advantages of the invention are that the chopped roving and liquid plastic, ordinarily a synthetic resin, are thoroughly mixed. A very minor fraction of the chopped roving, ordinarily fiberglass, is wasted whereas, in other conventional guns which are commercially available, a very important percentage of the chopped fiberglass is lost, ordinarily in the order of 35% to 40%, inasmuch as it falls to the fioor and/ or is not thoroughly mixed with the liquid plastic. The roving losses have been so materially reduced by the invention, which is to be considered as either original equipment or an attachment for existing guns, that the losses are in the order of 1%.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a top view of a gun equipped with means to practice the invention.

FIGURE 2 is a side view of the gun in FIGURE 1.

FIGURE 3 is a front view of the gun in FIGURE 1.

FIGURE 4 is a largely diagramamtic view showing the principal parts of the invention.

In the accompanying drawings there is illustrated a gun having

conventional gun sections

12 and 14 carried by frame 16 from which handle grip 18 depends. There is a trigger 20 to actuate the conventional guns, each of which is arranged to issue a stream of liquid substance, usually a synthetic resinous plastic in a spray pattern wherein streams 22 and 24 issue from the gun nozzles in a coplanar relation, but they converge at a slight distance in advance of the nozzles of the

gun sections

12 and 14.

Lines

26 and 28 are operatively connected with the gun sections and are under the control of the trigger 2a. In-

asmuch as the gun sections and the arrangement of the gun so far described is conventional, further detail is not given. Additional conventional parts include resilient roller 30 mounted for rotation on a spindle 32 that is mechanically carried by the frame of the gun. Idler roller 34 is located adjacent to resilient roller 30 and there is a cutter roller 36 with removable blades, driven by a motor-transmission unit 33, also attached to the frame of the gun. Roving 4t ordinarily long fiberglass strands, is fed through guide 42 carried by frame 16 and between

rollers

30 and 34. Roller St is turned by the blades of roller 36, and the roving is chopped into short lengths thereby.

Ordinarily, the chopped roving is fed by gravity flow or by a slight propulsion as can be obtained by the rotation of cutter roller 36, forwardly of the gun and into the merging

streams

22 and 24. But, this results in considerable loss of chopped roving and poor mixture with the liquid plastic that is discharged from the

gun sections

12 and 14. This problem is overcome by means of an attachment 5% shown best in FIGURE 4. The mechanism shown in this figure is considered an attachment since it may be installed as a conversion device for existing guns. Further, it is to be clearly understood that attachment 50 may be used as original equipment in the manufacture of guns without alteration as to principle and function.

Attachment 50 consists of a tube 5 2 having an open discharge end 54 and an open inlet end 56. The tube has a curved part 50 that turns upwardly from the longitudinal axis of the balance of tube 52, this balance of the tube represented at 6!} and made of a straight portion. The upper edges 62 of the inlet 56 may be contoured to follow the contours of

rollers

30 and 36 at the lower peripheries thereof, but it is to be noted from FIGURE 4 that the inlet 56 is in direct registry with the chopped roving which is discharged from the cutter roller 56. The inlet end of tube 52 functions as a funnel to receive this chopped roving while the balance of the tube functions to direct the chopped roving forwardly and in the same general direction as the

streams

22 and 24.

There are means for adjusting the elevation of the tube 50'. One end of the tube is suitably supported, for instance by a mechanical swivel or simply by air line 64 having an inherent amount of flexibility, e.g. a copper line. The opposite part of the tube is adjustable by turning an adjust ment nut 66 carried by adjustment screw 68. The upper end of the adjustment screw is secured to the lower part of tube 52, and the adjustment screw extends through an aperture in a bracket 79 attached to or forming a part of the base or frame 16 of the gun. In FIG. 4, turning nut 66 in one direction will lower the discharge end 54 of the tube against the yielding opposition of the supporting air line 64. Turning the adjustment nut in the opposite direction will leave the tube free to be elevated by the inherent resilience in line 64. More positive means for achieving this adjustment would include a simple addition of another nut on the screw 68; swivelly connecting screw 68 to tube 52 and threading the screw in a tapped opening in bracket 7 0; providing entirely diiferent types of mechanical adjustments, etc.

Air line 64 has a control valve 76 therein and is connected with an external supply of air under pressure. When air blows under pressure through port 78 at the curved part of tube 52, the air forms a venturi action, sucking the cut roving through the inlet 56 and expelling it under pressure through the discharge end 54 of the tube. The axis of the straight part of the tube is approximately coplanar with the discharge axes of

sections

12 and 14 so that the chopped roving merges with the

streams

22 and 24 of plastic and thoroughly mixes therewith. Any losses of chopped roving are negligible, and the chopped roving has the great advantage of being more thoroughly mixed with the liquid plastic.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. -A manually operable portable spray gun comprising power operated chopping means for cutting roving, a frame supporting said means, a pair of gun sections adapted to discharge plastic in a pair of converging spray streams mounted in coplanar spaced relationship on said frame, a hollow elongated conduit comprising an arcuate part and a straight part fixed to said frame between said gun sections and coplanar therewith, said conduit being open only at its ends so as to provide a discharge end and an inlet end, said discharge end being disposed in said straight part and in proximate alignment with the spray streams, the inlet of said conduit being substantially closed by the chopping means, an air nozzle mounted within said conduit between said ends and in axial alignment with said straight part and pointed toward said discharge end to direct a jet of air towards said discharge end, said jet creating a suction at said inlet whereby air is sucked over said chopping means thereby cleaning the same and sucking said roving into said conduit, said jet of air further discharging the roving through said discharge end, and a handgrip connected to said frame and extending transverse to the plane of said gun sections, one end of said conduit being resiliently connected to said frame by a resilient tube, one end of said tube being operatively connected to said air nozzle, the other end of said conduit being connected to said frame by a manually adjustable mechanism whereby said conduit may be properly aligned with said spray streams.

2. An attachment for a portable spray gun of the type having power operated chopping means for cutting roving and a pair of gun sections adapted to discharge plastic in a pair of converging spray streams mounted in coplanar spaced relationship upon a 'frame comprising a hollow elongated conduit including an arcuate part and a straight part for guiding and discharging said roving into said spray streams, said conduit being open only at its ends so as to provide a discharge end and an inlet end, said discharge end being disposed in said straight part, an air nozzle mounted within sm'd conduit between its ends and in axial alignment with said straight part and pointed towards said discharge end to direct a jet of air towards said discharge end to discharge the roving and to create a suction effect at the inlet end to suck roving into said conduit, means for resiliently connecting the attachment to said spray gun frame, said means comprising a resilient tube, one end of said tube being operatively connected to said air nozzle and manually adjustable means connecting the other end of the conduit to the frame.

References Cited in the file of this patent UNITED STATES PATENTS 2,255,189 Robinson et a1. Sept. 9, 1941 2,328,448 Gustafsson et a1 Aug. 31, 1943 2,585,133 Kempthorne Feb. 12, 1952 2,618,817 Slayter Nov. 25, 1952 2,702,261 Bacon et al. Feb. 15, 1955 2,787,314 Anderson Apr. 2, 1957 2,813,751 Barrett Iov. 19, 1957 2,850,421 Thompson Sept. 2, 1958 2,854,059 Palmer Sept. 30, 1958 2,860,687 Cole Nov. 18, 1958 2,870,054 Amos et a1. Jan. 20, 1959 2,929,436 Hampshire Mar. 22, 1960 2,933,125 Anderson Apr. 19, 1960 3,025,195 Kozma Mar. 13, 1962 FOREIGN PATENTS 204,774 Austria Jan. 15, 1959 817,875 Great Britain Aug. 6, 1959 560,254 Italy Apr. 2, 1957

Claims

1. A MANUALLY OPERABLE PORTABLE SPRAY GUN COMPRISING POWER OPERATED CHOPPING MEANS FOR CUTTING ROVING, A FRAME SUPPROTING SAID MEANS, A PAIR OF GUN SECTIONS ADAPTED TO DISCHARGE PLASTIC IN A PAIR OF CONVERGING SPRAY STREAM MOUNTED IN COPLANAR SPACED RELATIONSHIP ON SAID FRAME, A HOLLOW ELONGATED CONDUIT COMPRISING AN ARCUATE PART AND A STRAIGHT PART FIXED TO SAID FRAME BETWEEN SAID GUN SECTIONS AND COPLANAR THEREWITH, SAID CONDUIT BEING OPEN ONLY AT ITS ENDS SO AS TO PROVIDE A DISCHARGE END AND AN INLET END, SAID DISCHARGE END BEING DISPOSED IN SAID STRAIGHT PART AND IN PROXIMATE ALIGNMENT WITHTHE SPRAY STREAMS, THE INLET OF SAID CONDUIT BEING SUBSTANTIALLY CLOSED BY THE CHOPPING MEANS, AN AIR NOZZLE MOUNTED WITHIN SAID CONDUIT BETWEEN SAID ENDS AND IN AXIAL ALIGNMENT WITH SAID STRAIGHT PART AND POINTED TOWARD SAID DISCHARGE END TO DIRECT A JET OF AIR TOWARD SAID DISCHARGE END, SAID JET CREATING A SUCTION AT SAID LNLET WHEREBY AIR IS SUCKED OVER SAID CHOPPING MEANS THEREBY CLEANING THE SAME AND SUCKING SAID ROVING INTO SAID CONDUIT, SAID JET OF AIR FURTHER DISCHARGING THE ROVING THROUGH SAID DISCHARGE END, AND A HANDGRIP CONNECTED TO SAID FRAME AND EXTENDING TRANSVERSE TO THE PLANE OF SAID GUN SECTIONS, ONE END OS SAID CONDUIT BEING RESILIENTLY CONNECTED TO SAID FRAME BY A RESILIENT TUBE, ONE END OF SAID TUBE BEING OPERATIVELY CONNECTED TO SAID AIR NOZZLE, THE OTHER END OF SAID CONDUIT BEING CONNECTED TO SAID FRAME BY A MANUALLY ADJUSTABLE MECHANISM WHEREBY SAID CONDUIT MAY BE PROPERLY ALIGNED WITH SAID SPRAY STREAMS.