US1688021A - Pneumatic tool - Google Patents

Description

J. R. L.v SAN-ros PNEUMATIG TOOL med Dec. 15. 1922 oo. ds

Oct. 16, 1928.

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. provide a novel construction of valve and actuating means therefor whereby the valvev the piston Patented Oct. 16, 1928.

NroFFlcE.

JOHN R. L. SAN TOS, OF BALTIMORE, MARYLAND, ASSIGNOR, BY MESNE ASSIGNMENTS, l

'ro onions-o PNEUMATICTOOL NEW y JERSEY; I

COMPANY, OF NEW YORK, N. Y., A

coRPoRArroN 0F PNEUMATIC Toor..

Application led December 175, 1922. l Serial No. 607,184.

This invention relates to improvements inV percussive tools and has for one of its objects to provide an improved tool wherein the lmotive Huid for operating the piston or plunger is controlled by a both directions bylive air in distinction to being moved in one direction only by live air and in a reverse direction by compression that is produced by the piston or plunger' on one ot its strokes. Y f l j Another `object of the invention is to provide an improved construction of tool wherein or plunger' may be either longer or shorter thanits stroke. Y

A further object is to provide an improved structure wherein the valve, which controls the motive iiuid that actuates vthe plunger may be subject to a constant live pressure from one direction and to a variable continuous live air-pressure to move it in a reverse direction. v v

A still further object of the invention is to which has differential areas may bev subjected to constant llive motive pressureon both areas but in which the pressure on thelarger area will be vented whenthe valve'is to be moved by the pressure on the smaller area.

With these, and other objects in view, the invention is illustrated in the accompanying drawing, wherein,- Y l Fig. l shows a tool in longitudinalsection which or plunger nearingthe limit of lits operating stroke.

Fig. 2. illustrates a similarsectional view through the tool,-the section however being taken in a plane at a right angle to that of the view in Fig. l, the pistonor plunger nearingits return or 11p-stroke. v

Fig. 3 shows the detached valve in side valve that isactuated in,`

. the box and cylinder simply the present invention v.is fem-Y bodied,-the valve being down andthe piston,

and with thevalve up and,`

tains a piston or plunger 2. In the present instance the piston is shown with av length that is shorter than its stroke or shorter than one-half the length of the cylinderchamber, but this is not necessary and lthe invention is not to beso-constructed or restricted. y At the upper end of the cylinder there is provided a valve-box 3 with a valve 4 therein,-a disk v5 being interposed between quired ports and passages can be formed with more convenience when the disk and box are separate, as in this instance. l

A cap 6 titsk downoverthe box and disk and screws onto the upper end of the barrely and thereby locks the several parts together. At the lower end 0f the barrel there is pro` vided a working tool-7, such for example,ras a rivet-set and it is obvious that or plunger, on its down or forward stroke, Will strike the tool 7 and thereby vperform the Work for which lthe particular tool is designed., p v x l.

A live-air or motive-Huid supply-passage 8, extends through the cap-so that asupplyhose (not shown) may be connected therewith and' constantly supply live motive-fluid to' g said passage. j p A f f Anexhaust passage 9 is provided through the valve-box and cap and opens to the atmosphere for the exhaust of Huid pressure, as and for a purpose that will presently be'ex'plained. The cylinder is provided with a longitudinal channel 12,v whose upper end opens' through the disk v5, ybeneath the 'valve and whose lower end opens into `the cylinder-k chamberin a plane adjacent to an exhaustibecause the ref,

4the piston port Y10,'which latter extends through `the cylinder-wall to theatinosphere., v

the name valve lift-air-exhaustchannel"because .its function .is'to` ously-supplied lift-air from beneath the valve by venting it totheatmosphere throughtho x l cylinder-chamber andexhaustport l0. V

A passage 13 is provided in the valve-box 3, and the lower end offthfis passage, turns laterally and opens at the Vcenter of; the box y and at the underside yof the valve 4.

The upper end of this passage 13 isin constant communication with a live-air. supply, that will'presentlybe explained,-and for this reason I term this passage as a constant liveair valve-lift passage.

vTo distinguish ythe spaces in theV cylinder exhaust the continu lil) " around the exterior of. the valve,

above and below the piston or plunger 2, l designate the upper cylinder space as chamber 14, and the lower cylinder space as chamber 15.

The cylinder 1, is further provided with what I term a piston or plunger litt-channel 16 which latter extends from the lower end ot chamber 15, up into the valve-box 3 and turns inwardly to the center oli' the box where it opens at the side of the valve 4.

The box 3V is provided near its top with an annular groove 17 and an upper chamber 18, while a so-called Hip-chamber 2O is provided in the bottom ot the box.

The box alsohas a passage 21 whose uppe end opens into the upper annular groove l( and whose lower end extends down to and communicates with the cylinder chamber14 above the piston or plunger 2, as shown in broken lines in Fig'. 2 or' the drawing.

The valve 4 has a central passage 22, which extends from the upper end thereoit'downwardly and then turns laterally and opens into an annular circumferential groove 23 and it will be noted that this annular groove 23 is located on the larger diameter of the valve.

The cap 6 is provided with an annular liveair supply channel 26 which latter is in constant communication with the live-air supply 8, and it is this channel 26, with which the constant live-air valve-lift passage 13, is also in constant communication so that live air is constantly supplied tothe larger bottomV area of the valve 4.

The vallve has ahead 27, at its upper .end which is: designedv to enter the upper boxchamber 18 and this head is always subject to live air-pressure from the supply passage 8, so that both ends of the valve 4 are constantly subject to direct live air that has not been used to doany work.

O pemtz'oa.

In 1 of the drawing the piston or plunger 2' isl presumed to be moving downto strikethe working-tool 7. The valve 4l is down.

Live air fromy supply passage 8 will pass through chamber 18-to groove 17 of the valvebox then flow down through passage 21 of the box to the upper chamber 14 above the iston or plunger 2v and act on the upper end 'of the latter to drive it down.

As the piston 2 -moves down air from the lower chamber 15 of the cylinder maylexhaust through port 10 until the piston covers it and may also pass up through channel 16 and escapey around the reduced neck-part 28 of the valve, Vwhich at this moment is so positioned inthe box as to connect the upper end of the channel 16 with the exhaust port 9. This exhaust vfrom chamber 15 beneath the piston or plunger prevents the poclreting of air between the lower end of the plunger said valve as long as the lower end or' cylinder of channel 12, then and the inner end ot the working tool 7, so that the plunger can deliver a blow directly on Vthe tool.

The valve 4 will be kept down in Fig.V 1) notwithstanding the continuous delivery of live pressure through passage 13 to the larger under or cause lthis live air simply passes on down pas-v sage 12 into the cylinder below the piston and then exnausts through port 10 to the atmosphere.

Thus it will be understood that while constant live air is supplied by passage 18 under the valve 4', the pressure is not built up under channel 12 isvopen or uncoverec by the piston 2. Vhen piston 2 has moved down vin the cylinder far enough Afor its lower'end to cover the entrance to channel 12, further exhaust of the constantly supplied live air through passage 13 will be cut oit and immediately the pressure in said channel 12 and 'flip-chamber 2O under the larger lower endorl the valve 4 will build up (because ot the constant supply from 13 and no escape) and the valve 4 will then be moved up notwithstanding the Constant pressure on the smaller upper end or head 27.

This operation thus places the valve in ther rip-position shown in Fig.V 2 of the drawing.

The piston or plunger now being down and the valve 4v being up, live mitted beneath the plunger to litt the latter. This is effected as follows: y

Live air from supply passage 8 will pass down through the central port 22 in the top ot the valve then out into upper annular valve-groove 23 which latter, at this moment is in register with the upper end o'l'li't-channel 16ywhile the lower endy of said lift-channel opens beneath the plunger when the latter is down inthe cylinder. l

To enable the plunger tomove up, it is necessary to exhaust the pressure from its upper side that is in chamber 14 and this exhaust (when the valve is up) is from the bottom side of the valve, be-

air must be adtop ot the chan'ber 14 through passage 21 K to annular box-groovev 17 then down around the reduced neck 28 of the valve to and through the exhaust y When the plunger has moved up far enough to uncover exhaust port 10 and the lowerend the pressure from valvechamber 2O and the under side of the valve will escape bypassing down lthrough channel 12 into the cylinder Chamber 15 beneaththe plunger and out through exhaust port 1() to the atmosphere. l y

By thus relieving the `pressure greater bottom area of they valve, the constant pressure on the smaller topv or head 27, will push the valve down. The precise time at which this shifting of the valve takes place may readily be determinedr by the relative on the sizes of the box passage channel 12 (Fig. l);

Having described my invention, I claim,- l. In a percussivetool, a cylinder, aplunger, a valve-box having an upper annular chamber, an exhaust passage, a passage that extends through the kbox and opens into the upper end of the cylinder` and another passage that is continually supplied With live motive fluid and which extends from the upper side of the box and opens-at the center thereof near the bottom of the box, a. valve having tWo pressure areas one greater than the other the lesser pressure area being subject to 'a substantially constant pressure and the greater pressure area of the valve being subject to a 13 (Fig. 2) and the continuous pressure from the box-passage which is continuously7 supplied with livemotive fluid Which it ydelivers near the bottom of the box, means controlled by the plunger for conlining the continuously supplied motiveY fluid until the valve is shifted, and means comprisng a passage extending from the lower end oi the cylinder up to and through the valve-box, said passage at its upper end being provided With a lateral and inwardly extending opening, adapted when the valve is lifted to register With an annular channel formed about the valve, Which latter is in communication with a longitudinally extending passage formed in the valve body and in communicat-ion with the supply of live motive fluid.

2. In a percussive tool, a cylinder, a valvebox, a plunger in the cylinder, a valve in the box, said valve having differential areas, a cap itting over and holding t-he box and cyl- 'fecting the return or inder in rigid relation, means for supplying motive fluid in full volume to one side ot' the valve to subject the same to a substantially constant pressure, and means for supplying motive fluid in restricted amount to the other.

side of the valve to subject the latter side to continuous pressure, means for effecting a variation in the lat-ter pressure to move the valve against the constant pressure,V and means including an axial passage in said valve for supplying motive fluidV for the non-Working stroke of said plunger When said valve is Y valve to subject the same to substantially con'- stant pressure, means for supplying motive fluid in restrictedvamount to the opposite side of said valve to subject the latter side to continuous ressure, means 'controlled by the plunger 01' effecting a variation inthe said continuous pressure to move the valve against theconstant pressure, said valve having lan axial passage extending from said constant pressuremeans and terminating in an annular groove on the exterior of the valve, and means registering with said groove on shifting-of the valve by said continuous pressure for efnon-Working stroke of said plunger. Y

In testimony-whereof I ax my signature i JOHN R. L. SANTOS.

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