US2246535A - Pneumatic device - Google Patents

Description

June 2l, 1941.

c. G. PLAYFAIR PNEUMATIC DEVICE Filed April 19, 1937 2 Sheets-Sheet l {Ibi/ffii.. ,ladri/figlia.

Patented June 24, 1941 Nemrah TAT E S 6 Claims.

The present invention relates to a pneumatic conduit construction broadly adapted to provide air passages in various equipments.

Although not specincally limited thereto the present invention will be particularly described in application to a barrel device for a pneumatic tool which may be utilized for the actuation of polisher heads, cutting devices, saws, and other reciprocatory mechanisms or implements.

In the usual type of pneumatic tool with a barrel and piston, it is necessary to provide a valve means for alternately changing the pressure on opposite sides of the piston or differential pressure responsive device, which valve is connected with opposite ends of the piston by external tubing or passageways which must be most carefully and laboriously drilled into the cylinder body.

Even Where the cylinder is of relatively heavy metal of substantial thickness increasing the Weight of the tool, it is most dinicult to drill a straight passage therethrough for a considerable length to assure communication between the opposite sides of piston and the valve construction. And in spite of the high cost of these drilled passages it has been found preferable to utilize them as Vcompared to the difficulties encountered withexternal piping which prevents satisfactory gripping of the barrel andwhich is subject to being bent, damaged or broken upon handling.

It is therefore'arnong the objects of the present invention toh provide an improved pneumatic tool construction which may be readily and inexpensively manufactured at lowcost, and which will provide passageway connections between the' valve and the opposite sides of the piston, all with necessity of utilizing external piping Aand long drilled passageways thereon.

Another object isto provide apneumatic construction generally adaptable for pneumatic devices or for other purposes Where air, gases or iiuids are to be by-passed or controlled in their flow by means of valving means in connection with a main container, cylinder or passageway, without the necessity of utilizing an external piping and without the need for providing long drilled passageways.

In designing pneumatic tools of the character above described and particularly provided with elongated barrels, `it has 'not been found most satisfactory to provide reversing valve constructions or other valve mechanisms which must be actuated by external connections from the movement of the piston.

Particularly Where a rotary valve is employed to reverse connections to the piston and alternate the differential pressure applied thereto, it has not been found most satisfactory to use pinion and rack constructions Where the rack is actuated by a lost motion connection with the piston or with the reciprocatory element whether it be a reciprocating polishing or friction head, cutting tool, a iile or some other implement.

It is'therefore among the further objects of the present invention to provide a valve construction for a pneumatic tool of the character described, which valve construction may be actuated by the piston directly without the necessity for external rack and pinion connections and without substantial increase in the bulk or eX- pense of the pneumatic tool.

A still further object of the present invention is to provide an improved polishing head for a pneumatic tool of the character described which will readily accommodate itself to surfaces of various curvatures and shapes.

Other objects will be obvious or will appear during the course of the following specification.

In accomplishing the above objects it has been found most satisfactory to provide a cylinder say of steel or bronze tubing, which tubing is preferably punctured or holed in desired places where ports for pneumatic ingress or egress are desired.

These ports then may be covered by inverted trough or channel members designed to connect the desired ports, and these trough or channel members preferably are of sheet metal and flanged and the ports and trough or channel members are so arranged that the members will extend longitudinally on the outside of the steel or other barrel, parallel to the axis.

These ianges may then be line-welded o1' spotwelded or even soldered to the body of the liner.

The tube thus prepared with the flanged channel or trough members attached thereto is then positioned in a proper mold or die, into which a low melting or metal alloy, preferably aluminum, is poured, which metal alloy will then enclose the liner and the trough members attached thereto effectively sealing the various channels and troughs from each other and giving a relatively light weight cylinder construction which may be utilized as the handle of the tool with its initial roughened casting left as is, without finishing since this provides a better handV grip.

Within the barrel is preferably positioned a reciprocating valve and a piston, the valve being at one end and the whole tool being controlled by a manually actuated valve to admit or cut olf air pressure thereto.

rThe reciprocatory valve is preferably actuated by the air pressure and by the piston in its motion to move backwardly and forwardly, assuring the desired reciprocatory motion of the piston.

The polisher head which is shown by way of illustration preferably is supported on a rod, extending forwardly from said piston, and carried in an external tubular element substantially forming an extension of said cylinder, said tubular element may be provided with a handle at its external end and the tubular element may be slotted to receive a bracket for carrying the polishing head, cutting tool or other device.

The polishing head is preferably so connected with said bracket as to permit movement in two directions and give a universal joint eiect.

Other features will be specifically described in connection with the drawings, which show by way of illustration and not by way of limitation, one of the many possible embodiments of the present invention.

In the drawings:

Fig. 1 is a longitudinal section view of one form of pneumatic device according to the present invention.

Fig. 2 is a sectional view of the barrel and valve upon the line 2 2 of Fig. 1 with the valve in a diierent position.

Fig. 3 is a transverse sectional view at right angles of Fig. l with the barrel and valve in section and with the piston and valve in a different position than shown in Fig. 1.

Fig. 4 is an enlarged transverse sectional viev,7 upon the line 4--4 of Fig. 2, showing the barrel and valve construction.

Fig. 5 is an enlarged transverse sectional View of the barrel with the piston and valve removed therefrom.

Fig. 6 is a perspective view and partial section with the cast metal casing or covering broken away to more clearly show the construction.

Figs. '7 and 8 are enlarged diagrammatic sectional views illustrating the valve and piston operation.

Fig. 9 is a sectional View illustrating the end packing of the cylinder construction.

Referring to Figs. l to 3 the barrel A, provided with a piston B, an automatic valve C, a hand valve D, and an implement E taking the form of a polishing head.

The barrel to which the present invention is particularly directed is -best shown in Figs. 4 to 6 and it consists of a steel or metal liner 2Q, which is punctured or holed at suitable places indicated at 2l and 22 in Fig. 5.

The ports 2l and 22 are preferably so arranged longitudinally at the barrel that cooperating ports may be covered by the trough members 2B, 24, 25, 26, 21, 23, said trough members preferably being spot-welded at their iianges 29 to the body of the liner or sleeve 2t.

When these trough or channel members 23 to 29 are attached by welding of the anges 2Q to the shell or liner 2Q, the entire device may be placed into a form or die, in which the aluminum body or cover 3i! may be cast thereon to form the structure as best shown in Figs. 4 and 5.

This aluminum body may be left roughened with the irregularities of the die or mold and it may be threaded at its ends, as indicated at 3l and 32, to receive the caps 53 and Se of the pneumatic device.

The cylinder thus formed is of light weight, may be conveniently gripped, is inexpensively manufactured, and eliminates the need of drilling a cast metal barrel and the use of external piping.

This cylinder construction is the principal feature of the present invention and it is obvious that it may be applied to other devices, not speciically shown and/or described in the drawings of the present application.

The various passageways 23 to 28 may be made of any desired cross sectional area without the regard to sizing of drills or thickness of metal and the casting Sil will assure that no leakage will take place between the various trough and channel members. It is obvious that the construction described and the method of forming pneumatic passages may be applied to other devices such as carburetors or other domed cylindrical structures in which a sheet metal base is employed, suitably ported, the ports of which will be connected by suitable trough or channel members 23 to 28, as shown in 6.

The thickness of casting of the aluminum sheet Si@ may be varied and other metals may be readily employed, if their weights and melting points favorably compare to that of aluminum.

The valve structures C and D are not shown in detail in Figs. 1 to 3, the valve structure C being shown ybest in Figs. 7 and 8.

In the arrangement shown in Fig. 1, the air enters through the hose or tube 35, as indicated by the arrow 5t (see Figs. 1 and 3), and then passes the hand valve D, which is contained in the head of the cap 33.

As shown the end of the pipe 35 is screwed into a tapped bore 3l in the nipple 38 and enters into the bore `llii, which communicates with the peripheral bore it in the plunger portion 4i of the push valve ft2. lThe push valve l2 is held in position by threaded nut i3 and the spring M tends to elevate said plunger from the position shown in Fig. l to cut oi' the peripheral groove 40.

Air under pressure will be admitted to the barrel A, the piston B, and the valve C, when the plunger or hand valve D is depressed to the position, as shown in Fig. 1.

In the position of Fig. 1, the passage is feeding the recess M5, from which air under pressure flows through the channels, as indicated by the arrows in Figs. 1, 2, and 3. In Fig. 1 the air is owing into the right hand chamber F on one side of the piston. This will cause the piston to move to the left, exhausting the air in the left hand chamber G into the atmosphere through passageways in the barrel A and the valve C.

In the position of Fig. 2 the piston B is returning to the right and the valve C is in the inside position.

In Fig. 3, the poston has returned beyond the position of Fig. 2 and in short time will strike the valve C and return it to the position of Fig. 1.

The operation of the valve is more fully shown in the diagrammatic showings of Figs. '7 and 8, to which reference will now be had.

As previously described the air flows into the recess 46 from the inlet conduit 5l), the end of which is enlarged at 5l. From the chamber ,46, when the piston is moving to the right, as indicated by the arrow 52, the air will pass` from the chamber 55 through the port 53, the trough member 5G, which will be one of the members 23 to 28 of Figs. 4 to 6, through the port 55, through the annular recess 55, to the radial bore 51, the longitudinal bore the radial bore 59, the peripheral groove til, the port 6|, the trough member 52, the port G3 and to the chamber G, causing the piston B to move in the direction of said arrow 5,2.

During the movement of the piston in the direction indi-cated by the arrow 52, the air from the chamber F will be exhausted through the port 1|, the trough member 12, the port 13, the peripheral groove lil, and the atmospheric exhaust port 15 to the atmosphere.

It will be noted that shortly before the pi-ston has moved to the position of Fig. 'l in its leftward movement as shown by the arrow of Fig. 8 it has uncovered the port t4. From the port |54 of the air under pressure flows through the trough 95, the port et into the chamber 91, the air moving into the chamber 91 will cause the valve C to move from the position of Fig. 8 to the position of Fig. Y7, reversing movement of the piston B.

As shown in Fig. '1 the piston will move in the direction 52 until it strikes the valve `C and throws it back to the position of Fig. 8, the extension nipple 98 of the piston B cooperating with the recessed extension 69 on the end of said piston C, as shown best in Figs. 1 to 3.

When the piston B strikes the Valve C at the end of its movement in the direction as indicaited by the arrow 52, the port position will be changed as indicated in Fig. 8 and the piston will then move to the left in the direction in di-cated by the arrow 10 of Fig. 8. In Fig. 8 the air under pressure will flow from the chamber 46, the port 53, the trough 54, the port 55, the peripheral groove 5B, the radial bore 51, the longitudinal bore 59, the radial bore 1B, the port 11, the trough 18 and the port 19 into the chamber F.

At the same time, the air being exhausted will ilow from the chamber G through the port 80, the trough 9|, the port 82, the peripheral groove 83, the bores 9d, 95, 99, the peripheral groove 81, to the atmospheric outlet port 818.

The recess 89 having the should-er 90 and the back plate 9| will cooperate with the enlargement 92 on 'the back of the valve to limit the reci-procatory motion of the Valve C.

The back plate 9| is provided with a central bore 92, carrying the kicker extension 93, and is provided with a recess 94 receiving the enlarged portion 95.

lit is thus apparent that the valve C is automatically operated without external gearing or The piston itself is best sho-wn in Figs. 1 to 3,

and consists of a rear element 96 which has a threaded connection to the front cup element 91.

` the bore 99 of said front cup element receiving the actuating rod 99 which has the enlarged head |99, fitting in the recess lill between the piston elements 99 and 91. The fit between the bore 99 and the piston 99 is such that the piston may automatically aline itself in parallel-ism with the rod 99 even if the axes of the cylinder and rod 99 are not in alignment.

The packing ait the other end of the cylinder. as indicated by the letter H in Figs. 1 to 3, is shown in detail in Fig. 9.

In Fig. 9 the cap 34 receives three annular washers, the washers or gaskets |92 and l93 being of leather and the gasket |94 consisting of a steel disk. This steel disk preferably is closely fitted to the rod 99 and holds the gland packing |95 in position.

The bronze bearing |05 closely ts the rod 99 and also the interior of the tube |91, which tube is threaded at |08 to the nipple extension |99 of the cap 34. The lock nut Il!) presses the washer against the end of the nipple |99 prevents movement of the cap relative to the sleeve |01. 'It is appar-ent, however, that by tightening the cap 34 the gaskets |92, |93, and |94 are locked and sealed and then by turning the tube |01, the gland packing |95 is forced into the recessed end of the sleeve |99 to prevent a leakage around the piston shaft. The lock nut l 9 keeps the entire arrangement in position.

Referring to the tubing l01, the end of this tube is threaded, as indicated at |98, where it receives the tapped sleeve element which is provided with outturned ears 4, carrying the handle l l5 by means of the screws H6.

The lower portion of the tube is slotted, as indicated at |11. The end of the piston rod 99 is connected at H9 to the plate H9 which project-s through said slot l1. The piston rod 99 is slotted and the plate ||9 is inserted thereinto and riveted in place. The plate ||9 receives the openings E29, which in turn receive the ends |2| of the coil springs |22, the lower end of said springs |22 being attached at |23 by the screws |29 to the polisher head E.

The lower en-d of the triangular plate ||9 is also connected to the polisher plate through a linkage l25 pivotally mounted at |26 to the plate and at |21 to the upwardly projected lugs |28 from the body |29 of said polisher head.

The polisher head is covered by the flexible felt or absorbent material |30 which is in turn covered by the sanded polishing abrasive sheet It! preferably held in position around its periphery E32 by the snap ring |33.

In operation by grasping the handle l I5 in the hand and the roughened surface of the barrel A in the other hand and then by depressing the button D with the back of the hand, the air pressure may be turned on through the tube 35 to actuate both the piston B and the valve C to cause reciprocation of said piston and of said polishing head which may be applied with the desired amount of pressure to the surface being polished or abraded.

The pivot connections |29 and |21 and the linkage |25 will assure a substantially universal connection of the polisher head and will enable movement of said polisher head in Various directions.

It is thus apparent that the applicant has obtained a most useful and inexpensive tool of particularly desirable construction.

Many other changes could be effected in the particular features of construction designed, and in methods of operation set forth, without substantially departing from the invention intended to be dened in the claims, the specific description herein merely serving to illustrate certain elements by which, in one embodiment, the spirit of the invention may be eifectuated.

What is claimed is:

l. In a pneumatic tool, a pneumatic chamber provided with a thin sheet metal cylindrical shell, a cover .for said shell, a plurality of spaced ports in said shell, and a plurality of flanged thin sheet metal trough. members forming passages inside of said cover connecting said ports.

2. In a pneumatic tool, a pneumatic chamber provided with a thin sheet metal cylindrical shell, a cover for said shell, a plurality of spaced ports in said shell, and a plurality of anged thin sheet metal trough members forming passages inside of said cover connecting said ports, said cover consisting of an aluminium layer cast onto said shell.

3. In a pneumatic tool, a pneumatic chamber provided with a thin sheet metal cylindrical shell, a cover for said shell, a plurality of spaced ports in said shell, and a plurality of passages inside of said cover connecting said ports, said passages taking the form of elongated thin sheet metal troughs spot Welded onto the exterior of said chamber.

4. In a pneumatic tool, a pneumatic chamber provided with a thin sheet metal cylindrical shell, a cover for said shell, a plurality of spaced ports in said shell, and a plurality of passages inside of said cover connecting said ports, said shell being a cylinder, said passages taking the form of elongated thin sheet metal troughs on the ex- CFI terior o1 said cylinder and said cover taking the form of an aluminium casting.

5. In a pneumatic tool, a pneumatic cylinder consisting of a steel shell, a plurality of ports in said shell, a plurality of elongated thin sheet metal trough members on the outside of the shell, and a die cast aluminium cover in said shell covering said trough members.

6. In a pneumatic tool, a pneumatic cylinder consisting of a steel shell, a plurality of ports in said shell, a plurality of elongated thin sheet metal trough members on the outside of the shell, and a die cast aluminium cover in said shell covering said trough members, the periphery of said trough members being flanged and said flanged portion being Welded to said shell.

CHARLES G. PLAYFAIR.

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