US1352191A - Pneumatic tool - Google Patents

Description

F. L. mima.y

PNEUMATIC TooL.

APPLICATION FILED JULY 14, |919.

,A 1,352', 1 91 Patenteaspt. 7, '1920.v

` 3 SHEETS-SHEET 3.

UNH'D' STATES PTENT; FFICE.

FRANK L. HENIG, or CHICAGO, ILLINoIs, AssIeNoa To IIENIG ENGINE oo., or CIIIcACo,

' ILLINoIs, A CORPORATION or ILLINOIS.

PNEUMATIC TOOL.

Speceaton of Letters Patent.

raten-ted sept. v, Iazo.

Application filed vJuly 14, 1919. Serial No. 310,813.

To all whom t may concern v -Be it known that I, FRANK L. HENIG, citi- Zen of the United States, residing at Chicago, in the county of Cook 'and State of Illinois, have invented certain new and useful Improvements in Pneumatic Tools; and I do here-by declare the following to. be a. full, clear, and exact description ofthe invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to fluid-operated percussive tools, such as pneumatic hammers, one of its general objects being to provide a tool of this class which will be simple and cheap in construction, which will have a relatively low recoil; and one which can readily be operated both with wide variations in the pressure of the fluid and with wide variations in speed. Furthermore, my invention aims to provide a tool of this general class in which the admission, exhaust and cushioning of the fluid are all controlled partly by the movement of the piston and partly by a single and` relatively light valve member; in which the valve member is semil balanced and hence responsive in movement to slight pressure variations; in which continuous Operation at a high degree of eiiiciency may be obtained without a high degree of accuracy in the machining of the parts, and in which the operating eiiiciency of the appliance may therefore be well maintained even after the parts show wear as the result of prolonged service. Furthermore, my invention aims to provide atool of the class described in which the effective action can easily be varied, thereby permitting a ready adjustment. of the tool for different conditions, and one in which the weight and movement' of the valve member are both so slight as to render the same practically noiseless. Still further objects will appear fromthe following specification, and froml the accompanying drawings, in which drawings Figure 1 is a central and longitudinal section through the barrel and part of the handle of a pneumatic riveting hammer embody` ing my invention, showing the position of the 'parte during the initial part of the forward stroke vof the piston.

Fig. 2 is a fragmentary section showing the valve in its forward position while the piston is traveling rearwardly.

Fig. `3 is a longitudinal and centralsection through another embodiment of my invention, namely one in which the valve member has only a single groove. v 7

Fig. 4 is a transverse section through the tool of Fig. 3, looking forwardly `from the rear end of the ma-in cylinder, or from thek line 4-4 of Fig. 3.

Fig. is a transverse section through the same tool taken along the line 5-5 of Fig. 3, with the valve in the same position as in Fig. 4.

Fig. 6 is a longitudinal section'similar to Fig. 3, but showing the positionof the'parts when the piston is approximately at the middle of its return stroke;

Fig. 7 is an enlargement of a part of Fig. 6, with some of the Huid passages omitted to avoid confusion.

In the embodiment of Figs. 1 and 2, the tool of my invention includesv a cylinder l having a main bore 2 enlarged at its forward end to house the shank 3 of a rivet setting tip. The main bore 2 slidably houses a piston 4 and this bore is desirably enlarged at its rear end to house a sleeve 17 which has portions of numerous entrance and eX- haust passages formed in it, this separate sleeve being employedy for thevconvenience in manufacturing the tool. rFhe sleeve 17 has a bore which slidably houses a singleA valve member controlling the entrance and exhaust passages,` as hereafter more fully described. Threaded upon the cylinder 1 at the rear end of the latter is a handle 5 having a bore 8 through which compressed air is supplied 'for Operating the tool. Thisl handle desirably has the end of its threaded bore arranged for abutting against the rear end of the sleeve 17, so that the handle clamps this sleeve firmly in its normal position.

rFhe valve member desirably consists of a '40 .t'he'fo'mvard end of the cylinder.

as hereafter described@ Thus arranged, the cylinder land the sleeve 17 together form the barrel of the tool, which barrel is pro-- vided with pass-ages, duplicated in the bar- 5 rel to'any desired number to afford therequired'total cross section, onlyY one of each of the passages being shown in the sectional views of Figs. l and 2, to avoid confusion in reading :the drawings; Thus, the

sleeve 17 has an entrance passagev 9 opening at itsV rear end into'the borc- S of the handle and opening at its forward end into the main bore 2 of the barrel at point slightly forward of thervalve memberwhen the latter is in its rearward position. 'lhis passage 9 therefore affords an inlet for vthe compressed air to the rear of the barrel or behind the vpiston 1l. Likewise, the passage lleadingfrom the forma-:d end of the bolre2 to a point near the rear end of the sleeve will afford means for admitting the compressed'airfto the forward end of the Y bore '2vbu't this passageflhas an inlet portion 2O lwhich extends radially inward of the sleeve and which is closed by the cylinder part 18 when the valve 'is in its rearward position. rlhe passage l5 also has another connecting portion 2l which alines with the groove @of the valve memberl when the rlatter inits rearward position, so that this Vgroove connefts the passage 2l with an outlet duct l2 opening to the outer air and having one yofits inlets in alinement with the passage 2l. Consequently,

when the valve isin its rearward position,

the forward end of the bore 2 is connoited through the passages l5 and 21..,and through groove 6, with the outlet. duct l2,

the rc r therebyT affording an exhaust passage for it the vsame time, the forward groove 'Y of the valve member affords another connection to the outlet l2, namely to the intermediate exhaust passage .l0 which opens into the bore 2 ata point somewhat ahead of the piston when the latter is at its starting point. Initially, the piston will therefore be moved forwardly by theconipressed air entering through the passage 9, and the air in front of thi'oughboththe passages l0 andl. y "lll/.hilo this is occurring, the valvemenr ber isinaintai erl in its Yree '.1 5rd position bythe compre o itself, since this air presses against both faces of the web 2G and the larger diameter of the forward end of the valve member produces a differential effect Vtending` to move this'member toward the'rear and therefore holding it in its rearmost position. rlhe valve is therefore held 'lirmly in position, while the piston travels. forward. In moving forward, the piston vfirst shuts olf the connection from the foix ward end of the bore 2 to the intermediate exhaust passage l5, and when the piston the piston will beV expelled has entirely passed the forward end of this i passage l0, the latter is automatically connected to the part of thev main bore behind the piston. Consequently, thecompressed air which still lentersthrough the inlet'9 can exhaust through the passage l0 vas soon as the piston has moved entirely vand rear faces of the Vvalve member, the

actuating air will move the` valve member forwardly to the position of Fig. 2, thereby bringing the groove 6 out of alinement 85v with'any ofthe passages in the barrel and therefore disconnecting the outlet l2 from the passage 'l5 leading to the forward end of the bore As the valve moves forward, its rear end exposes the terminal portion 20 of the passage l5, so that the actuating air from the bore of the handle can flowV through the passages 20 and l5 to the extreme forward end of the bore 2, thereby admitting livel air' in front of the piston. Pit the same time, the forward groove 7 has moved out of alinement with the intermediate exhaust ylO and intoalinement with the rear end of a compression-controlling passage Lile\'vise,tthe shoulderrat the juncture of the'two differentially diametered portions of the valve member has moved away from its stop and the smaller diameter of the portion adjacent to the groove 7 cooperates 105 with the latter in connectinO the passage 13 with the outlet l2, asshown in Fig. 2. rThis passage 13 therefore affords an exhaust outlet for the rear of the cylinder, while the original inlet 9is shut off by the forward 110 l portionof the valve member.

' lW ith the valve in this forward position, the pressure of the live air admitted through the passage lo forces Vthe piston rearwardly,

and the air back of thevpiston'exhausts 115 freely through the passage 13 until thepis-V ton itself closes the entrance to this latter .passage and thereby 'entraps theV residual air between the rear end of the piston and the valve member. As the piston continuesv 120 its rearward movement, this entrapped air iscompressed, and as soon asthe resulting pressure overbalances the'pressure of the live air on the rear face of the valve member,l the valve is moved rearwardly toI its initial position, after which the above described cycle ofL operation is resumed..r j

lowever, while have heretofore described my invention in an embodiment in` which the valve member has two grooves,

the differentially diametered'valve portions,

as shown in Figs. B'to 7 inclusive. In this case, the said shoulder closes the connecting bore 14 while the valve is in its initial position, while the groove 6 connects the passage 15 with the outlet 12 (as shownin Fig. 7)

and the inlet 9 acts as in the first described embodiment. l/Vhen the piston has entirely passed the mouth of the intermediate passage 10, this connects the groove 6 with the rear portion of the bore 2, and the'groove in turn affords a connection to the outlet 12. Consequently, the air behind the piston Vexhausts through this outlet, thereby reducing the pressure on the forward face of the valve until the pressure of the live air on the rear face of the valve slides the latter forward into the position of Fig. 6.

I/Vhen the valve has thus moved forward, its larger diametered portion exposes both the upper outlet of the'compression-controlling passage 13 and the lower end of the bore 14, so that the air behind the piston can exhaust through this bore 14 after the piston has closed the inlet to the intermediate passage 10. However, when the piston during its rearward strolre also` passes the inlet of the passage 18, the'exhaust for the rear of the cylinder is shut off and the entrapped air is then compressed between the piston and the valve until the resulting pressure moves the valve back toits initial position of Figs. Sand 7. This shuts off the supply of compressed air to the forward end of the cylinder and restores the initial air supply and exhaust connections for the cylinder. The cycle of operations is then resumed, the rate of reciprocation being governed by the pressure at which the air issupplied, and by .the distance which the piston has to move before closing the inlets from it to the passages 10 and'13. Y

It will be obvious from the above that with both of the described embodiments nov complicated shape whatever is required for the piston, as a simple solid cylinder suffices. for this, and that the valve member can be quite light and easily constructed since it has no bores whatever through the same. It will also be obvious that by increasing or decreasing the number of the ports, and by shifting the connections of the passages 10and 13 'to' the cylinder longitudinally of the latter, I' can readily vary-the operation'ofmy appliance,including the extent to which the entrapped air is com-V pressed by the piston during. its rearward stroke. 'So also, with a completely 'maniev factured tool, I V.can effect a considerable variation by simply plugging up a part'of the ports, as for example by the simple'expe-dient of slipping nails into the v-rearendsv ofthe passages 9.. v w

Moreovensince the valve member is subjected on bothjfaces to the pressure of the actuating' `fluid during lalmost the entire forward stroke of thev piston, the tendency for fluid Vto leak past this' valve is `practically negligible, so that I do not require an exact itand amable to operate the tool of my .invention successfully even after the parts have shown considerable wear. VSo also, since the shoulder on the piston when in its rearward position `is pressed tightly by the air pressure against the correspond ing shoulder in the sleeve. 17, I make vit difficult for the .exhaust to leak around the valve when `the valve is in its rearward position, and hence do not require an exact fitting at these points. Furthermore, by employing a` plurality of ports arranged about the axis of the main cylinder, I am able to use relatively small bores for each and can therefore work with a quite short longitudinal movement of the valve member. Then, since this valve member is nearly balanced by the pressures against its oppositerfaceis, and since I'can readily commonly required as the minimum` for.

operating pneumatic tools, namely with pressures ruiming down to only one or two pounds.

-I claim as my invention:

1. In a rpneumatictool, a cylinder, ton therein, an inlet for the cylinder, a

a pissingle exhaust outlet, an exhaust and an l intermediate passage inthe cylinder, a compression-controlling lpassage in the cylinder, and a valve having means whereby in one position to connect said exhaust outlet and. intermediate. passage to the cylinder and ina second position to connect the vcompression-controlling passage to said exhaustl outlet.

2. In a. pneumatic tool, a cylinder having a piston' therein,fan exhaust outlet, aA pair of vpassages. in the cylinder leadingto the forward end and to an intermediate point in the cylinder, a third passage leading into the cylinder rearwardly of the intermediate point, and a valveV in the cylinder having twoy grooves arranged for connecting the exhaustoutlet respectively with said pair of passages in one position of the valve and ina second position to have one of its grooves connect the third passage with the exhaust outlet.

3. In a pneumatic tool, a'barrel having a Vpiston reciprocatingin the-boreof the barrel, an exhaust outlet, the barrel 'hav-Y ing a pair of passages leading respectively to the forwardend and -to an intermediatev point of the said bore, means whereby to con- Vey fluid to the piston to return same te initial position, and a slidable valve having.

two grooves disposed `for ,connecting the exhaust outlet respectively with the said passages in one position of the valve and in a second position to render said means operative. Y

4. In a pneumatic tool, a cylinder, a pis-A ton therein, said cylinder Vhaving an exhaust outlet, and further V having a 'pair of passages leading respectively to the Vforward end and to an intermediate point inthe cylinder, and a third passage rearwardly of the pair of passages, and a valve for controlling the passages and having means'whereby in one position to connect the pair of passages to the exhaust outlet'and in av second posi-Y tion to disconnect said pair of passages from the exhaust outlet and to connect the third passage to vthe exhaust outlet.

In a pneumatic tool, a cylinder, a pis-V ton therein, a sleeve having ajlongitudinal inlet passage opening atvits ends into andY adjacent the sleeve ends, an exhaust in thecylinder and sleeve, an exhaust outlet 1n the cylinder and sleeve, means whereby to y convey fluid to the piston to return same to initial position anda slidable valve in the sleeve formed when inv its rearmost position to connectv the exhaust and exhaust outlet and to render said means inoperative and when in its forward position to close the forward end of the inlet passagev and render said means operative. y

6. In a pneumatic-tool, `a cylinder, a pistonv therein, Va sleeve having a longitudinal inlet passage opening at itsrrends into and adjacent the sleeve ends, an exhaust inthe cylinder andv sleeve, an exhaust outlet in thev 1 cylinder and sleeve, an intermediate passage in the sleeve and cylinder, means whereby to convey fluid tothe piston to return same to initial position and a vslidable valve in the sleeveformed when in its rearmost posi-- tion to connect the exhaust and exhaust outlet and when in its forward position to close the forward end of the inlet passage and to effect communication between the intermediate passage and the exhaust outlet andrender said means operative. Y' 7. In a pneumatic tool, a cylinder, a piston therein, a valve Vhaving an enlarged forward end and having a pair of Aspaced peripheral grooves, an exhaustpassage and an exhaust outlet in lthe cylinder, and an intermediate passage anda rear passage in the cylinder arranged and related to the valve grooves so that whenv the latter is in its rearmost position the exhaust and intermediate-.passages will be ,connected by the respective pair of grooves to the loutlet and when the valve is in its forward position the rear passage willrbe connected to the outlet by one or" said grooves. Y y

8. In a pneumatic tool, a cylinder, Va piston therein, an exhaust outlet, a compression controlling passage, Yan exhaust passage and an intermediate passage all formed in the cylinder, and a valve control formed for connecting the exhaust and intermediate passages-to the exhaust outlet in one position ef the valve and in a second position of the latter-to connect the compression-controlling passage to the said outlet.

9. In a pneumatic tool, a cylinder, a piston therein, an inlet passage leading at one end intothe cylinder, a valve slidable between the ends of the inlet passage and formed in one position to cover said end of the passage, an exhaust and intermediate passage leading into the cylinder, an outlet for the cylinder and a` pair of peripheral groove passages formed in the valve to connect the exhaust and intermediate passagesV to .the outlet in,v one .position of the valve,

"and meanscontrolled bythe valve to convey liuid to the piston to return same Yto 'lateral terminals, means whereby to convey fluid to the piston to return same to initial l position, and a slidable valve having a pair of peripheral grooves which yin one position ofthe valve register with the .respective lateral terminals and -in asecond position render said means inoperative and bring said grooves and terminals out of register.

l1. In a pneumatic tool, a cylinder, a piston therein, an exhaust and an intermediate passage in the cylinder, an exhaust outlet in the cylinder, a compression-controlling passage in the cylinder,means whereby to convey fluid to the piston to return same to initial position andv a valve control which in one position connects the exhaust and intermediate passages with the exhaust outcompression-controlling passage to the eX- haust outlet and renders said means operative.

12. .ln a pneumatic tool, a cylinder, a piston therein, an exhaust passage leading to the forward end of the cylinder, an exhaust outlet leading to the outer air, means Whereby to convey iuid to the piston' to return same to initial position and a valve control having a peripheral groove, both the pas-k sage and outlet terminating opposite to the peripheral groove of the valve control so as to connect same in one position of the valve control and vsaid valve being iormed so as to render said means operatlve 1 in a second position of the valve.

Signed at Chicago, Illinois, July 1,1919.

FRANK L. HENIG.

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