US1791582A - Vibrator - Google Patents

Description

Feb. 10, 1931. J. T. STONEY 1,791,582

VIBRATOR Filed June 28, 1924 m MW Patented Feb. 10, 1931 UNITED STATES PATENT Pris JOHN T. s'roniiy, or CLEVELAND, onro, ASSIGNOR rona nonn n. s'ronnr, or LAKEWOOD, OHIO VIBRA'IOR Application filed June 28, 1924. Serial No. 722,971.

This invention relates to vibrators of the Referring to the accompanying drawings, fluid operated reciprocating plunger type and the vibrator casing consists of an outer cylin-- is an improvement over the vibrator covered drical casing 1 which is open at one end and an by my co-pending application Serial N o. inner cylinder 2 which is adapted to be in- 628,158, filed April 2, 1923. serted into the outer casing through the open This invention is designed particularly for end thereof, the rear end of the cylinder 2 use in foundries for cleaning sand from castbeing closed by an end plate 3 which bears ings by the method disclosed in my applicaagainst the integral rear wall of the outer tion Serial N o. 7 22,970, of even dateherewith, casing, andthe outer end of the inner cylin-- e and has for its objects to provide a fluid operderbeing-closed and held in place by means of so ated vibrator which is effective in carrying a front closure member 4 which has a porout the operations above referred to and in tie-n that fits within the end of the outer caswhich the impact of the piston in one direcing and has flanges 5 overlying the edge tion is effectively cushioned without impartthereof, the flanges 5 being secured to the ing vibrations to the cylinder casing or supcasing by means of tap bolts 6. The inner s porting frame. cylinder is held against rotative movement It has been found that the castings may be in the casing by means of a screw stud 7 cleaned much more rapidly by eliminating which is screwed into a threaded opening in the vibrations due to impact of the piston or the outer casing and projectsinto an opening striker against the end of the cylinder on its in the inner cylinder. Extending through return stroke and additionally it has been the closure member 4 at the center thereof is found that a vibrator such as disclosed herea percussion member 8 which fits in a central in may be used informing sand molds. By opening in the head l, projects beyond the in imparting vibrations to a mold filled with her face thereof to receive the impact of the loose sand by a rapid succession of sharp piston and is provided with an enlarged head taps or percussive impacts in one direction 9 against which the casting 10 to be cleaned only, the same may be caused to quickly settle is held as shown in Fig. 4-. l/Vhen the vibraand pacl: in the mold. tor is used for compacting the sand in a mold, With the above and otherobjeots in view, the cylinder is mounted in vertical position v39 the invention may be said to comprise the beneatha mold supporting table 11 as shown as device as illustrated in the accompanying in Fig. 5 with the percussion member bearing drawings hereinafter described and particuagainst the underside of the table. Within larly set forth in the appended claims, tothe cylinder there is mounted a piston or gether with such variations and modificastriker 12 which has two peripheral grooves 35 tions thereof as will be apparent to one forming three spaced peripheral flanges 13,

skilled in the art to which the invention ap- 14 and 15 which have-a sliding fit within the pertains. inner cylinder 2. Between these flanges the Reference should be had to the accomannular grooves form with the wall of the panying drawings forming a part of this cylinder two annular chambers 17 and 18.-

4o specification in which Fig. 1 is a central lon- The chambers 17 and 1.8 are separated by the so gitudinal section through the vibrator; Fig. central flange 14 which is imperforate, the 2 is an end elevation of the vibrator with a chambers 17 and 18 being in communication portion broken away to show the exhaust with the-interior of the cylinder at opposite ports in section; Fig. 3 is a side elevation of ends of the piston through annular rows of as the piston; Fig. l shows the vibrator arports 19 and 20 throughtheflanges 13 and 15. ranged in horizontal position with a casing An air inlet chamber is formed in the wall of held against the percussion member; Fig. 5 the inner cylinder by a bore 21 extending shows the vibrator shown in vertical position longitudinally from the forward end, the with the vibrator bearing against the underend of the bore being closed by a screw plug '50 side of a mould supporting table. 22. The inlet chamber 21 communicates ing and communicates with the chamber, a

suitable valve 26 being provided in the pres sure line to control the admission of pres.

sure to the cylinder. An annular exhaust chamber 27 surrounds the inner cylinder 2 substantially midway between the ends thereof, the chamber 27 being formed by complementary grooves formed in the inner surface of the outer e sing and the outer surface of the inner cylinder. Communication between the interior of the cylinder and the exhaust chamber 27 is established through either of two parallel ci culnferentially extending rows of exhaust ports 28 and the air escapes from the exhaust chamber through an exhaust pipe 29 which is attached to the outer casing and communicates with the exhaust chamber adjacent the ports 28. The

7 two rows of ports 28 are so positioned that as the piston moves past the. ports pressure is exhausted alternately from opposite sides of the piston so that as pressure is being admitted to one side of the piston, air permitted to escape from the opposite side. Once thepiston is started it will continue to reciprocate as long as pressure is supplied to the cylinder due to the automatic reversal of pressure by the movement of the piston past the ports. The reciprocating movement of the piston is so rapid that in normal operation of the vibrator the leakage of air as the piston passes the central point is very slight.

A cushioning plunger 30 is mounted within the rear end portion of the cylinder, the cush- H ioning plunger 30 having a sliding fit within the cylinder which is counter-bored to provide a shoulder 31 to limit the inward movement of the plunger. The plunger 30 is normally held against the shoulder 31 by fluid pressure supplied through an inlet pipe 32 which communicates with the chamber33 between the plunger 30 and rear end plate 3 through a port 34 in the cylinder 2 adjacent the end plate 3. The plunger 30 is cupsha )ed and has airearw'ardly extending skirt or ange 35 which serves to center and guide the plunger, A body 36 of a suitable liquid lubricant such as oil fills or partially fills the chamber 33 and this liquid together with the air serves toproduce a cushion effect as the plunger 30 moves towarl the plate 3. The movement otthe plunger 30 under the impact of the piston is cushioned by the body of air and oil under pressure, and the inioning plunger 30.

creasing resistance to movement of the plunger due to the liquid and air within the chamberbrings the cushionin plunger to a full stop after a slight movement thereof and before it actually impinges against the rear end plate so that the impact of the piston is completely absorbed and not transmitted to the cylinder 1. It should be noted that as the plunger moves toward the rear of the casing the skirt or flange 35 passes across the port 34 thus reducing the size of such port and impeding the escape of fluid "from the space between the end of the plunger and the cylinder. W

The plunger 30 fits in the cylinder loosely enough to permit a slight leakage of air past the same into the space behind the piston 12 and this leakage serves, when the vibrator is mounted in horizontal position, to shift the piston and hold'it in its forward position in engagement with the percussion member 8 whenever the vibrator is stopped by shutting off the valve 26, so that the piston cannot be stopped at dead center position. l'V hen mounted in vertical position as shown .in Fig. 5 the weight of the piston 12 overcomes any pressure due to leakage so that the piston, whenever the operating pressure is out cit, drops by gravity to the lower portion of the cylinder in which position the inlet port 24- communicates with the underside of the piston and the upper side thereoi is open to the exhaust ports so that the piston will always be operated when the operating pressure is admitted to the cylinder. The (JHSliiOllil'lg device also serves to lubricate the vibrator since in the operation thereof a sufiicient amount of oil will be forced past the plunger 30 into the main chamber of the piston to properly lubricate the piston.

In the operation of the vibrator the piston rapidly reciprocates and impinges alternately against the percussion member 8 and cush- The vibrations produced by impact against the percussion member are transmitted to the work while the vibrations due to impact against the cushioning plunger are entirely absorbed and dissipated by the fluid pressure and its cushion action. Thus all vibrations except those produced by impact against the percussion member are eliminated so that vibrations are transmitted to the work, either the casting to be cl aned or the mold in which sand is to be packed in one direction only.

It will be understood that when in the specification and claims I refer to the mold supporting table, I mean a table for supporting a mold flask, a core box or any containerin which sand or other material is to be compacted.

lVhile I have disclosed my vibrator with relation to a molding machine and a machine for removing sand from castings, I do not thereby limit my invention to such uses only.

Having described my invention, I claim:

1. A vibrator comprising a cylinder having 3 a reciprocating piston therein and provided pressure into the piston chamber at one side of the piston to prevent the same from stop ping in a dead center position with respect to said ports.

:2. A viorator comprising a cylinder having a reciprocating piston therein and provided with inlet and exhaust ports so positioned with respect to the piston as to be opened and closed bythe piston to reverse the direction or" movement thereof, and a cushioning device at one end of the cylinder comprising a plunger slidable in the cylinde' and means "for admitting pressure between the plunger and end wall or" the cylinder, said plunger permitting leakage of pressure into the main chamber of the cylinder to prevent the piston from stopping in a dead center position with respect to said ports.

'3. A vibrator comprising a cylinder having a reciprocating piston therein and means for supplying fluid thereto to operate the piston,

said cylinder having a percussion member at one end to receive the impact of the piston, a plunger slidably mounted in the opposite end of the cylinder, means for limiting the inward movement of the plunger, means for maintaining fluid pressure between said plunger and the end of the cylinder, and means for impeding the escape of fluid from the space between the plunger and the adj acent end of the cylinder to prevent jarring impact against said end.

at. A vibrator comprising a cylinder having a reciprocating piston therein and means for supplying fluid pressure thereto to operate the piston, and means for cushioning the stroke of said piston in one direction com prising a plunger slidably mounted in an end portion of the cylinder and movable toward and from the adjacent end wall, means for limiting the inward movement of the plunger, and means including a port opening into the cylinder adjacent said end wall for supplying fluid pressure between the plunger and adjacent end wall toward which it moves, said plunger having a part adapted to move over and restrict said port as the plunger approaches said end wall.

5. A vibrator comprising a cylinder having a reciprocating piston therein and means for supplying fluid pressure thereto to operate the piston, and means for cushioning the stroke of the piston in one direction, comprising a cup shaped plunger slidably mounted in the end of the cylinder and movable toward and from the end wall of the cylinder, said plunger having a cylindrical flange projecting toward the adjacent end wall of the cylinder, means for limiting the inward movement of the plunger, and means for supplying air under pressure to the chamber formed between the plunger and end wall of the cylinder comprising a port in the cylindrical wall of the cylinder adjacent the end wall over which the edge of said flange moves as it approaches said end wall.

In testimony whereof, I hereunto afi'ix my signature.

JOHN T. STONEY.

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