US822146A

US822146A - Pneumatic hammer.

Info

Publication number: US822146A
Application number: US3621200A
Authority: US
Inventors: Edward C Meissner
Original assignee: Chicago Pneumatic Tool Co LLC
Current assignee: Chicago Pneumatic Tool Co LLC
Priority date: 1900-11-12
Filing date: 1900-11-12
Publication date: 1906-05-29
Anticipated expiration: 1923-05-29

Description

PATBNTBD MAY 29, 1996.

E. C. MEISSNER. PNEUMATIC HAMMER.

APPLIGATIUN FILED Nov.12, 1900.

? @gli 6 7 .,f//J7//Vl//zf/l/f//l//l//f bri/UUR /suff No. 822,146. PATENTED MAY 29, 1906.

E. C. MEISSNBR. A PNEUMATIG HAMMER.

Arrmoulox FILED Bov.12, 19.00.

2 SHEETS-SHEET 2.

Ihren/r.'

TED STATES PATENT CEEICE.

EDWARD C. MEISSNER, OE ST. LOUIS, MISSOURI, ASSIGNOR, BY MESNE ASSIGNMENTS, rIfo CHICAGO PNEUMATIC 'TOOL COMPANY, A CORPO- RATION- OE NEw JERSEY.

' PNEUMATIG HAMMER. f j

EL No..822,146; .Specification of Letters Patent.- 'i VIa-.texited. MaySQQ-I19O. Appiicauoumeanovgmbe'r12,19o. smania. 36,212;

= T0 dll wil/0m it may @1000m/f' form of construction-as to the supplemental Be it known that I, EDWARD C. MEISSNER, exhaust, in which the exhaust passes' to.thej .5 5 .a citizen of the United States, and a resident atmosphere directly or transversely throughf.` I' ofthe city of St. Louis and State of Missouri, a wall ofthe cylinder.

5 have -invented vcertain new and useful lm- The principal elements of my construction y; rovements in. Pneumatic Hammers, of are a handle, a valve-bushing 2,'Fig. 10, .1n-n y ,l Vwhich the following is a specification. closed in said handle, a valve 3, Fig. 11, in 6o My invention relates to what are comsaidbushing, a barrel or oylinder'4-,1-clamped monlyknown as pneumatic hammersgand to said? handle in alinement therewith, l" -1 'o lthe object thereof is to produce a hammer of 1, 2, and 12, and a pston in said cylinder. this character having novel and advanta- VThe motive fluid employed will conj geous features of construction and operation venience be referred to ascompre'ss' air] 65 U -wl1ich. will be apparent from the description The handle comprises a:grasping"iportion-`z i hereinafter given. and a cylindrical portion Yhavin ajcy-lindlfie'a Chief among the advantages of'my hamsocket extending nearly the fulllengt'hth 'I ,ner may be mentioned, first, a novel 'and eili-` g of, Fig. 12. The `purposeiof this:,so'ek'eigy cient valve and valve movement 5 second, the contain theivalveand valv -bushing; biitffor v7o'.; "provision of supplemental exhaust and, reasonspof economy f, and c.onvenience". "go third,'jthe provision of means for cushioning manufacti'iije-it is preferable to fit asepflrate-f-jl he rearward stroke of the.. piston orplungerfi'v cylindrical sleev'e or socket piece 1' injthe inthe presentinstance 1` l1ave shown `my vsocket ofthehandle rathe'thanmount the."A ,Y nventin-embodied-inwhat isdlesgnated a valve-bushing directly in the'handlefscket- 7 5 longistrokdfor "'riveting. hammer, in itself. Thissocket-piecelis, in eecttaf 'art which the piston has a length of stroke ofthe handle and constitutesla valve ck; j greater thanfitsown length and in which my The bushing 2 iits in the rear end nventionvfinds useful application; but my socket, and the end ofthe barrel or cylin v'rl 1 nventiony isf-not limited to this Species of 4 is reduced to lit' into the fore end of .saidf Y8o hammer.` Y socket-piece and abut a lainsi; the endof they thev accompanying drawings, which bushing, the loore at t e fore end of/ said-f formpart 'fof this specification, and wherein socketiece being enlarged to accommodate.

ocfcur,'Figure 1 is a central longitudinal secsurface of said cylindrical ortionof'thehan- -8 5 tin.pf my device, Showing the valve in its dle is threaded to alloWa t eaded sleevel to?4 fj rearmost oropen position. Fig. 2 is a simiwork thereon, and the front end of-Said 3511er. view showing the valve in its foremost sleeve has an inwardly-extendin "ange 7 .orclosed-pcsition.' Fig. Sis across-sectional which overlaps and engages aL s oulderf" view on the dotted line 3 3 of Fl.g.l. Fig. 4 formed on the cylinder in posti'on tofabu lis a cross-.sectional view on .the lince 4 ofv against the end of thclmndlef- The rearend Fig. 1; Fi 5 is a cross-sectional view on the of said sleeve is provided with ratchet-teeth" 40 line -5 5 of vig. 1. Fig'. 6 is a cross-sectional 9, Fig. 9, anda spring-pressed boltlO, 'ro-. view on the line 6 6 of Fi 1. Fig. 7 is 'a' vided with ratchet-teeth 11 in'its e'n ,ris cross-sectional 'View on the line 7 7 of Fig. 1. mou Ited on the handle position to' e11' -95 Fig. 8 is a crass-sectional view on the line 8 8 ga e the .teeth on said collar, and thereby of Fi 1. Fig. gis@ detail side viewshowing loc i said-collaragainst rotation, f 1 45 theevice for preventfrng the unlocking of Thef-valve-bush' g 2 is a cylindrical .sleeve Athe threaded collar. Fig. 10 is a sectional iittin tightlyinthesocket-pieceofthehadle, l detail view of the valve-bushing. Fig. 11 is a Yand t e valve 3 isa cylindrical vpiece"J fitting roo sectional detail view of the valve. Fig. 12 in' said bushing and movable endwise thereisnan enlarged.l longitudinal section of the in. The valve-bushing has holes extending '50*v` upperend of the hammer with the parts through the sidev thereof and loca-ted -as fl' in thepositions shown in Fig. 1; and Fig. lows, Figs. 10 and 12: One ofsaid holes 12 A 13, Ia section of the intermediate portion oi' is located back of the rearmost position of the 1, o5f. `'.thecylinder or barrel, illustrating a mndifv'. valve. and the

other holes

13, 14, 15,. 116, '17,*

ab@ n likesymb'ols refer to like parts wherever they said re uced end of the cylinder. The outer f "Il :l

and 18 are opposite the valve in its advanced covered when the valve is in its rearward position, Fig. 12. Back of the admission-port 13 are three

ports

15, 16, and 17, the foremost, 15, of which communicates with a passageway 20, extendin longitudinally through the wall of the va ve-block and the wall of the cylinder, and terminating in a port 21 in the forward end of the cylinder. The rearmost, 17, of said three ports communicates with a passage-way 22, extending longitudinally through the wall of the valve-block and thewall of the cylinder and terminating in a port 23, formed in a circumferential groove 1n the cylinder, near the rear end thereof. Themiddle port 16 of said three communicates with theatmosphere through a passageway 24 in the valve-block and handle and constitutes the main exhaust-port of the device. Two grooves 25 26 are formed in the valve 3 in position.' to register alternately with the exhaust-port 16. The front groove 25 registers at all times with the foremost, 15, of said three ports, and the rear groove 26 registers with the rearmost, 17 of-said three ports at all times. By this construction the front end of the cylinder is vented or exhausted through the port 21, passage-way 20, port 15, groove 25, and the main exhaustport 16 and passage-way 24,.when the valve 1s in its rearward position, Figs. land 12, admitting live air to the rear of said cylinder, and when the valve is in its forward position, Fig. 2,-tl1e rear portion of the cylinder isopen to the atmosphere through port 23, passageway 22, port 17, groove 26, main exhaustport 16, and passage-way 24.

vIn order to effect the movement of the valve 3, an annular rib 27 is formed on the rear end thereof, Fig.- 11, whereby zthe cross"- sectional area of the rear end exceeds that of the front end. In other words, the valve is of the differential type, whose larger pressure area in the present instance faces rearwardly and whose smaller ressure area faces forwardly., The bore of t e bushin is enlarged at the rear end to'form a cham er or space to; accommodate said rib, Fig. 10, and the shoulder 28 thus formed in said bushin limitsthe forward movement of the va ve. The rearward movement of -said valve is limited by a hollow or concaved lug or cap 29 in the end of said bushing and aving a flange extending over the end thereof.

The outer front ledge of this-cap is recessed,A

the barand notches or holes 30 are formed in said end and lie opposite the rearmost port 12 in the bushing. `From this ort -12 a passa eway 31 extends through t e handle and t e wall of the cylinder to a port 32 in the middle portion of the cylinder between the ports 21 to 23, hereinbefore mentioned. In the operation ofthe device as soon as the piston or plunger'5 in its forward movement uncovers the intermediate port 32 air from the cylinder flows through said port 32, passage-way 31, and port 12 into the space in the rear of the valve 3 and exerts pressure upon the rear end of said valve. Both ends of the valve are thus submitted to pressure from the same source; but the ressure on the rear end of the valve exceeds t at on the front end by reason of the area of the rear end being the larger. Consequently the valve moves forward to the positionillustrated in Fig. 2 and shuts ofl` the admission of air into the rear end of the cylinder. A vent-hole 33, formed throu h the handle and the bushing at the shouler thereof, permits the admission and escape of air in front of the rib 27 on said -valve, andfthus keeps the pressure thereon' constant.

The return of the plunger is effected by live'air admitted into the front end of the of a tool or button set 34 fits therein tiofht enough to secure a sufficient pressure. Trliis live air enters the front end of `said cylinder throughl the duct or passage-way 20, which communicates with the ort 15 of the bushing in frontv of the main exhaust-port 16. For this purpose a small port 14, Fig. 10, communicating with the main air-duct 19 is formed vin the bushing 2 back 'of the main admission-port 13 in position to register with the first groove 25 of the valve in the forward position thereof and in position to be closed y the end portion of said valve in the rearward position thereof. By this arrangement as soon as the valve is moved forwardly to close the main admission-port 13 tothe rear end of the cylinderand bring-its front groove 25 into register with the small port 14 of the su ply-duct, Fig. 2, live air enters the front en of the cylinder through the small duct 14, front groove 25 ofthe valve, port 15,

passagefway 20, andl port 21. As the rear end of the cylinder is open to the atmosphere while the valve is in its forward position, the air admitted through the small duct 14 into the front end of the cylinder forces the piston rearwardly. In order -to prevent the accidental return of the valve to its rearward position, the small duct 14 is bored at such an angle `as to cause the air flowing therethrough to impinge against the front wall of the front groove o the valve, whereby the pressure on said front wall is greater than the pressure on the rear wall. i v

' .In addition to the exhaust through the` IOO IIO

` from the valve into the cylinder,

seal-i6 l lead directly through the wall of the cylinder,-

as illustrated in Fig. 13; but it is preferable to have it extend longitudinally through the -wall thereof and through the handle, as in Figs. 1, 2,.and 12,so that the expelled air will not interfere with the work. As clearly illustrated in Figs. 1 and 2, taken vin connectionwith Figs. 4, 5, and 6, a supplemental exhaust'- passage 56 extends from its port 55 rearwardly through the body or wall of the barrel or cylinder, through the reduced rearward end of such cylinder, Fig, 4, through a portion of the cylindrical socIiet piece or bushing 1 and then emerges on the inner wall of said socket piece or bushing in position to register with the circumferential groove 16, which is in constant communication with the main or regular exhaust-port and passage 24, as clearly illustrated in Fig. 6. Obviously the outlet end of passage 56 may be differently positioned for communicating with the outer air, if desired. The functions of this supplemental exhaust are to release the pressure at the front end of the cylinder before the piston completes its return stroke, so that said piston will not have a forcible impact at the rear limit of its stroke to decrease the resistance to the advancing piston by increasing the rapidity of exhaust from the front end of the cylinder, also to cooperate with the main exhaust-port in releasing the pressure at the rear end of the cylinder just before the piston reaches the limit of its forward stroke, whereby the piston rebounds freely after its impact, and thus avoids objectionable jarring. Y

In order to protect the valve against the possibility of impact of the piston, the rear end of the cylinder is closed by a plate or block 60, hereinafter designated a cushionplate. This plate consists of an imperforate circular body portion and an annular portion on the rear face of said body portion. The outer diameter of 4the annular portion is llarger than that of the body. The bore of vthe cylinder is enlarged at the rear end and the annular portion of the plate fits in said bore and abuts against the shoulder formed by such enlargement. In order to admit air a slot 61 is cut in the annular portion of said plate in register with a slot or port in the end of the cylinder. This last-mentioned slot commucates with a passage-way 62, extending forwardly inthe wall of the cylinder, and opening into said cylinder through a port 63 a suficient distance from the end thereof to affordV a suitable cushion for the piston, as hereinpressure after described. By this arrangementA the air admitted in the rear of said cushion-plate passes through the slot thereof and thence f through the passage-way in the cylinder-wall and enters the cylinder near the rear end thereof. In operation the piston upon its return stroke closes the port 63 of the passage-way 62. The air thus confined in the rear end of the cylinder is compressed to fa higher degree than the normal or ordinary working and not only constitutes a positive cushion, but initiates the forward movement of the piston and drives it far enough to uncover the admission-port 63.

' It is desirable in ariveting-harnmer-to have a button set incorporated as a part thereof. v

For this purpose a nosing or sleeve 3 5 is inserted and rigidly secured in the end of the cylinder. The projecting end of this sleeve is enlarged and has a groove 36 formed in the periphery thereof. In this groove fit the flanges 37 of two semicircular pieces 38, which project beyond the end of the nosing. These pieces 38 are firmly clamped in place by a strong circular spring or resilient split ring 39,which rests in ooves 40,provided therefor in the outer sur aces of said pieces, whereby said pieces constitute clamping-jaws for holding the shank of the button Set or tool, Figs. 1 and 3. In order to better perform this function, each of the clamping-jaws is provided with a groove 41 on its inner face and the shank of the button set or tool is provided with a rib 42 for interlocking therewith, said rib and grooves being preferably beveled to facilitate insertion and removal of the button The shank of the button set fits in the nosing tight enoughl to insure the retun of the piston, but the rib and grooves are arranged to permit a slight endwise movement of the shank.

The admission of air is controlled by a throttle-valve in the handle. This valve is a hollow cylindrical cup 43, ittin in a tubular sleeve 44, which is set into a cy indrical bore in said handle. The middle portion of this bore is enlarged to form an annular oove 45 around said sleeve, and the sleeve 1s provided with a series of perforations 46 in register with said groove. The outer end of said bore is threaded and is closed by a threaded cap 47, fitting thereon and constituting an abutment for a helical spring 48, which rests inside of said sleeve and bears against said cup. The admission-duct 19 extends from a tap at the side of the handle into the groove around said sleeve and from the bottom of the bore to the main-valve admission-port 13. The spring keeps the valve-cup normally in its advanced position, so that its sides close the perforations in the sleeve, and the air is admitted or shut off at the perforations in the sleeve according as the valve-cup is in its backward or advanced position. The movement of the valve-cup is effected by a lever set or other tool.

IOO

IOS

lIO

; the operator.

formed in said handle to admit a short rod 49, mounted on the handle in position to be conveniently manipulated by the thumb of For this purpose a-hole 1s 50, which extends from the lever to the cup, whereby'the motion of either is transmitted to the other. In order tovequalize the pressure on the opposite sides of the valve-cu a small hole 51 is formed through the en of said cup. Y l

For the sake of clearness, brevity, and convenience of description the foregoing specification assumes thateach port and each passage-way have a separate function from the others. In practice, however, it is better to form circumferential grooves inthe valvebushing at the pointshereinbefore designated for the several orts and to have a plurality -of ports extendlng through the bushing from `the bottom of each groove. This construction not only balances the pressure on the side of the valve and provides a large port area, but also avoids the necessity of having the ports made to registe So, too, instead of single passage-ways above described a plurality of passage-ways may be used for each. The operation of my hammer. is as follows: Upon the manipulation of the lever 49 'the throttle-valve in the handle is opened so as 3o to admitv live air through the air-supply duct 19. When the valve is in its rearmost posi- ,hp

pressure in the rear end of the cylinder to retion, as shown in Figs. 1 and 12, the air-supply duct 19 communicates with the rear portion of the Ycylinder through the port 13 4in advance of its front endand the passage-way l62around the cushion-plate, and live air is admitted into said cylinder through said port 13 and passage-way 62. In this position of the valve the front end of the cylinder is open to the atmosphere through the port 21 in its end, the passa e-way 20, the port 15 in the valve-bushing, tIie front groove 25 of the valve, and the main exhaust-port 16 in the bushing and exhaust port or .ports 24, through the handle-socket to the atmos here. -The front end of the cylinder is also ectly open to the atmosphere through the-port 55 and passage-way 56. The live air admitted in the rear portion of "the cylinder therefore drives the piston forwardly without affecting the position of the valve until it passesand uncovers the port '32. When the port 32 is uncovered, the live air in the rear portion of the cylinder passes therethrough and through the passage-way 31 and the port 12into the -space or chamber in the rear of the valve. As

the rear end of the valve is of larger area than` the front end andy both sides are submitted todirect or cylinderpressure, the valve fis' driven forwardly to the position illustrated in Fig. 2. This movement of the valve closes tlr'emain admission-port 13, and at the same time it opens communication between the main exhaust-port 16 and the port 17, which'l communicates vthrough the passage-way 22 and port 23 with the rear portion of the cylinder. At the same time the front port 21 of the cylinder and its passage-way 20 are cut off from the main exhaust port 16 and brought into communication through the front groove 25 of the valve with the small port 14, communicating with the air-supply duct, so that live air is admitted to the front end of the cylinder. By this arrangement the air is cut off from the. rear of the piston andadmitted to the cylinder in front thereof before it reaches the limit of its stroke. The theory of this arrangement of ports is that by 'the time the pistonis passing the port 32 it has acquired a very rapid speed, and its momentum will carry it a considerable distance before the air admitted through the port 32 shall have had time to effect the movement of the valve, so that the piston will impart its stroke with very little resistance by reasonof air being admitted in front-of it. In this forward movement of the piston the supplemental exhaust-port 55 serves to increase Y the rapidity of exhaust from the front end of the cylinder until the piston is nearing the limit of its stroke, and after the rear end of the piston has passed said port 55, said port serves to release the pressure in the rear of said piston, whose motion at this time is continued by its own momentum. When the iston delivers its stroke, there .is very little sist its rebound, and at the same time live air is being admitted in the front end of the cyla inder to effectthe return of the piston. At the beginning of the return stroke of the piston the rear portion of the cylinder is vented lthrough the port 23, passage-way 22, port 17 of the bushing, rear groove 26 of the valve and main exhaust-port 16, and also through the supplemental exhaust-port 55 and passage-way 56. The supplemental exhaustport 55 is closed near the beginning of the backward stroke; but no effect is produced on the valve until the piston covers the port 23. When, however, the piston covers the port 23, the escape of air from the rear end of the piston-chamber by the exhaust is cut 0H and the further rearward movement of the piston compresses the air sufiiciently to cause it to return the valve to its rearward position, Fig. 12, the pressure passing from the pistonchamber to the front end of the valve-chamber for that purpose through the port 63, passage 62, and port 61. In order to insure the return of the valve lat the proper time, the valve may be loosely fitted in the bushing, or a port 64 may be drilled in the bushing from the admission-port through the front end of the bushing, Fig. 10, so as to remain uncovered by the valve at all times. By this arrangement live air is always bein admitted vin front of said valve without pro ucing any rearward position.

port 23 is closed by the piston, as in Fig. 12, the live air in the rear of the piston coperates with the air compressed by the returning piston to force the valve backwardly into its When the valve is thus forced back, it is in the position shown in Figs. 1 and 12 and ready to renew the operation hereinbefore described. The piston on its backward stroke passes the port 63, and thereby prevents the admission of'air back of the piston; but the initial forward movement of the piston is effected by the expansion of the air confined and compressed in the rear end of the cylinder by the return stroke of the piston.

As hereinbefore suggested, the supplemental exhaust instead of? being led rearwardly through the body of the cylinder to the main .or regular exhaust 24 may be led directly to the atmosphere by a port or passage extending laterally through the wall of the cylinder, as' clearly indicated in Fig. 13, in which such supplemental exhaust-port is shown at a.

p What I claim is- 1. A pneumatic hammer comprising a cylinder having ports for the admission and escape of air, a piston in said cylinder, and a valve for controlling the admission andrelease of air, said cylinder having a supplemental exhaust-port located in the forward portion thereof in position to be uncovered by the piston shortly after the initiation of its return movement and before the comple- `tion of such return movement, substantially 5 as described.

2. A pneumatic hammer comprising a cylinder having ports for the admission andI escape of air, a piston in said cylinder, and a valve for controlling the admission and release of air, said lcylinder having a supplemental exhaust-port located in the forward portion thereof in position to be uncovered by the piston shortly after the initiation of its return movement and before the completion of such return movement, said supplemental exhaust-p ort being permanently op en `to the atmosphere,substantially as described.

3. A pneumatic hammer comprising a cylinder having ports for the admission and release of air, a piston in said cylinder, a handle portion fastened to said cylinder and having a cylindrical socket-piece closed at one end and nested therein, and a cylindrical valve in said socket-piece in alinement with said cylinder, said valve having grooves in its side to coperate with the inlet and exhaust ports, substantially as described.

4. A pneumatic hammercomprising a cylinder having ports for the admission and release of air, a piston in said cylinder, a handle portion fastened to said cylinder and having a cylindrical socket-piece closed at one end and nested therein, said cylinder having a reduced end portion fitting within said socketpiece, and a cylindrical valve in said socketpiece in alinement with said cylinder for controlling the inlet and exhaust ports, substantially as described.

5. A pneumatic hammer comprising a handle portion having -ports for the admission and release of air, a cylinder, a piston in said cylinder and an imperforate valve for controlling the admission and release of air, one of said ports being in the rear of said valve and communicating through a passage-Way with the middle portion of said cylinder, said valve having two grooves in its side for coperation with some of said ports, and having its rear end of larger diameter than its front end, substantiallyas described. y

6. A pneumatic hammer comprising a`c'ylinder having ports for the admission and release of air, apiston in said cylinder, and a handle clamped to said cylinder and having a cylindrical socket portion, the outer portion of said socket being enlarged and the end of said cylinder being reduced to iit tight therein, and a valve-bushing in the rear portion of said socket provided with portsfor the admission and release of air, anda lon itudinally-movable valve in said bushing a apted to coperate with said bushing-ports, substantially as described.

7. A pneumatic hammer comprising a cylinder, a piston therein, a handle having a cylindrical socket portion, a valve-bushing in said socket and a valve in said bushing, the rear end of said valve being enlarged and fittinor in the enlarged bore of said bushing, and

thebfront end of said valve fitting loosely in IOO said bushing to permit the leakage of air by said front end, said hammer being provided with ports and passage-ways arranged lto be controlled by said valve and said piston, substantially as described.

8. A pneumatic hammer comprising a cylinder having ports for the admission and release of air, a piston in said cylinder, and a valve for controlling the admission and release of air, said cylinder havin a supplemental exhaust-port located in t e forward portion thereof imfposition 'to be uncovered by the rear end of the piston shortly before the forward limit of the piston-stroke, and by the front end of the piston soon after the beginning of its rearward stroke, substantially as described.

9. A pneumatic hammer comprising a cylinder having ports for the admission and release of air, a piston in said cylinder, and a valve for controllin the admission and release of air, said cy inder havin a suppl mental exhaust-port located in t e-forward portion thereof in position to be uncovered by the rear end of the piston shortly before the forward limit of the piston-stroke and by its front end shortly after the beginning of its rearward stroke, said supplemental exhaust-port being permanently open to the atmosphere, substantially as described..

10. A pneumatic hammer comprising a cylinder having ports for the admission and release of air, a piston in said cylinder, and a handle clamped to said cylinder and having a cylindrical socket portion, the outer portion said cylinder being reduced to `it tight therein, and a valve-bushing in the rear portion of said socket provided with ports for the admission and 'release of air, and having its bore enlarged at the rear end, a cylindrical valve in said bushing having a shoulder at its rear end fitting in the venlarged portion of the bushing-bore and having grooves for coperatingwith ports in said bushing, one of the ports in said bushing being located at the rear of said valve and communicating through a passage-way in the socket portion and cylinder-wall with` a port near the middle portion of the cylinder, substantially as'described. i v

12. A pneumatic hammer comprising al cylinderhavingports for theadmission and release of air, a piston in said cylinder, and a handle clamped tosaid cylinder and having a cylindrical socket portion, and a valvebusliing in said socket provided with Aports for the admission and release of air and havv in its bore enlarged at the rear end, a cylindrical valve in said bushing `having a shoulder at its rear end fitting in the enlarged portion of the bushing-bore and having grooves for cooperating with ports in said bushing, one of the ports in said'bushing being located at the rear 'of said valve and communicating through a passa e-way in said socket portion and cylinder-wa l with a port near the middle portion of the cylinder,- substantially as described. V t K 13. A pneumatic hammer comprising a cylinder, a piston therein, a handle portion fastened to said cylinder and having a socket constituting a continuation ofthe cylinderchamber, a valve-bushing in said socket, and a valve in said bushing, said valve having two circumferential grooves and being enlarged at its rear end, and said hammer having a passage-way extending from the rear of said valve to the middle rportion of said cylinder, and a main admission-port in position to be covered by the front end of said valve in its forward position and to be uncovered when the-valve is in its rearward position,y

and a main exhaust-port in position to register'with the two grooves alternately, and a.

passage-way extending from the front end ofl the cylinder to a portwhich registers with hammer comprising a -the front groove of 'the valve, and a passageway which extends from the rear portion of the cylinder to a port which registers with lthe rear groove of the valve, and a supplemental admission-port in position to register with the front groove of the valve when said valve is in its forward position, substantially as described.

14. A pneumatic hammer comprising a cylinder, a piston therein, a handle portion' fastened to said cylinder and having a socket portion, 'a valve-bushing in said socket, and a valve in said bushing, said vvalve having two circumferential grooves and being enlarged at its rear end, and said hammer havl ing a passage-way extending from the rear of said valve to the middle portion of said cylinder, and a main admission-port in position to be covered by the front end of said valve in its forward position and to be uncovered when the valve is in its rearward position, and a main exhaust-port in position to register with the two groovesalternately, and a passage-way extending from the front end of the cylinder to a port which registers with 'the front groove of the valve, and a passageway which extends from the rear portion of the cylinder to a port which registers with the rear groove of the valve and a supplemental admission-port in position to registerY with the frontA groove of the valve when said valve is in its forward position, and a supplemental exhaust-port leading from the middle portion of the cylinder to the atmosphere, substantially as described.

15. A lon -stroke pneumatic hammer comprising a cy inder having its front end closed IOC with the shank of a tool, and a handle fastened to said cylinder and Vhaving a cylindrical socket portion, a bushing insaid socket havingits bore enlarged at the rear end, a valve enlarged at the rear end and iittingin said bushing, and a piston in said cylinder, said-bushing having circumferential grooves in its outer surface and ports extending through said bushing from said groove and arranged to be controlled by said valve, said hammer having passageways extending from said groove to the atmosphere and to the front and rear ends of the cylinder, and a passage-way extending from the rear of the valve to the middle portion of the cylinder, substantially as described.

16. A pneumatic hammer comprising a cylinder, a piston therein, a handle fastened to saidcylinder in alinement therewith and having a cylindrical socket portion, a bushin in said socket and a valve in said bushing, said bushing having circumferential grooves with ports leading therefrom to the interior of said bushing, the main admission-ports being in position to be covered and uncovered by the front end of said valve, and the rearmost port being at the rear of said valve, and

said hammer having passage-ways extending IIO 'rif

- from three intermediate grooves in said bush-l ing to the front and rear ends of the cylinder and tothe atmosphere respectively, substaninterior of said bushing, the main admissionports being in position to be covered and uncovered by the front end of said valve, and the rearmost port being at the rear of said valve, and said hammer havmg passageways extending from three intermediate .grooves in said bushing to the front and rear ends of the cylinder and to the atmosphere respectively, substantially as described.

18. A pneumatic hammer comprising a cylinder, a piston therein, a handle having a A socket, the outer or forward end of the socketpiece being enlarged and the rearward end of the cylinder being correspondingly reduced to fit into said enlarged end of the socketpiece, a valve-bushing located in the socketpiece and having ports and passages for the admission and exhaust of the motive fluid to and from the cylinder, anda valve arranged in the valve-bushing for governing said ports and passages; substantially as described.

19. A pneumatic hammer comprising .a handle portion having ports for the admission and release of air, a cylinder clamped to said handle portion, a piston in said cylinder, and a valve in said handle portion for controlling the admission and release of air, said valve having a groove therein and said handle portion having a small duct inclined forwardly in position to cause the air to impinge against the front Wall of said groove, substantially as described.

20. A pneumatic hammer comprising a handle portion having ports for the admission and release of air, a cylinder clam ed to said handle portion, a piston in said cy inder, and a valve in said handle portion for controlling the admission and release of air, said valve havinvr a groove therein and said handle portion thaving a small duct inclined in position to cause the air to impinge against the wall of said groove, substantially as described.

21. A pneumatic hammer comprising a cylinder, a piston therein, ports for the admission and release of air, a valve for controlling the admission and release of air, and a duct leading from the air-supply duct and opening in position and direction to cause the air to impinge against the valve in the general direction of its line of motion, sub-v stantially as described.

22. A pneumatic hammer comprising a handle portion having a cylindrical socket, a

socket-piece therein, abushin in said socketpiece and a valve in said bus g, and a cylinder clamped to said handle portion in alinement therewith, and a piston in said cylinder, said bushing, handle portion and cylinder having continuous passage-Ways therethrough for the admission and release of air, and al of said passage-Ways being controlled entirely by said valve and piston, substantially as described.

23. A pneumatic hammer comprising a handle Cportion having ports for the admission an said cylinder, and a valve for contro ling the admission and release of air, said valve being located back of said cylinder and in alinement therewith, and an imperforate plate in the rear end of said cylinder, substantially as described.

24. A pneumatic hammerv comprising la cylinder having ports for the admission and release of air, an imperforate plate at the rear end of said cylinder, a iston in said cylinder, and a handle clam e to said cylinder and having a cylindrical) socket portion, a valvebusning in said socket portion, and a valve in said bushing in alinement with the cylinder, the pressure-admission ort extending from the space back of said p ate to'a point in the piston-chamber sufficiently far from the rear end thereof to constitute an air-cushion therein, substantially as described.

25. A pneumatic hammer com rising a cylinder having passage-Ways for t. e admislsion and exhaust of pressure, and a valve controlling said assage-ways and constructed to permit lea age of air from the valvechamber to the rear end of the cylinder; substantially as described.

26. A pneumatic hammer com rising a cylinder having passage-ways for t 1e admission and release of air, and a reciprocating valve for controlling said passage-ways, said hammer having a passage-way extending from the supply-duct to the end of the valvechamber beyond the range of movement of the valve, substantially as described.

27. The combination, in an impact-tool, of a cylinder, a piston reciprocable therein, inlet and exhaust passages for the motive fluid,

and a valve movable in a chamber at one end of the cylinder and serving to control the flow ol motive fluid to and from each end of the cylinder, one face of said valve being ppen to a chamber in which motive fluid 1s compressed by the piston as the latter approaches one end of its stroke, and the other face of the valve being open to a chamber to which motive fluid under normal pressure is admitted.

28. The combination in an impact-tool, of

a cylinder, a piston reciprocable therein, inlet and exhaust passages for the motive fluid, and a valve movable in a chamber at one end of the cylinder and serving to control the flow release of air, a cylinder, a iston in IOO IIO

motive fluid to lan cylinder, said valve having one face open toi 4a chamber in which motive fluid is compressed by the piston as the latter approaches lone end of its stroke, and another face of :.larger area than the first open to a chamber p o which motivefluid under normal pressure 29. In a pneumatic tool of the type deio scribed, a valve to,cntrol the admission and exhaustv to and from the cylinder, said valve being actuated by direct air-pressure at one stroke of the piston and by-compression of' the air between 'it and the piston at the return stroke;

30. The combination in an impact-tool, of a cylinder, a piston reciprocable therein, inlet and exhaust passages for the motive fluid, a valve movable in a chamber atone end of the cylinder and serving to control the flow of motive fluid to and from each end of the cylinder, said valve having an enlarged head, and one face of the valve being open to a chamber in which the motive fluid is com- 'ressed by the piston as the latter approaches one end of its stroke, and a passage leading fromthe chamber which receives the enlarged head of the valve to a point' in the cylinder where it will be uncovered by the piston 3c when the latter reaches the forward limit of its stroke, whereby the valve will be moved in one direction by motive fluid compressed by the piston at one end of its stroke, and in the other direction by motive fluid under normal pressure when the piston reaches the other limit of its stroke. l 31. In a fluid-pressure-operated tool, the

combination with a cylinder, of a reciprocating piston therein, a valve-casing, a diHerential piston-valve in said casing controlling the supply and exhaust of fluid-pressure to and from the opposite ends of the cylinder, said valve-casing and cylinder having ports and passages whereby the valve ismoved in one direction by air compressed by the piston and in the other direction by fluid-pressure flowing through the cylinder from the supplyort. p 32. In a pneumatic hammer comprising a cylinder having passage-ways for the admission and release of pressure and a reciprocating'valve for controlling said assage-ways, said valve having one end tting against leakage in the valve-chamber andhaving its other end arranged to permit a leakage of air into one end of the valve-chamber to insure the movement of said valve, substantially as described.

33. In a pneumatic hammer, a valve to control the admission and exhaust of motive fluid to and from opposite ends of the cylinder, said valve being moved in one directionby air compressed by the piston and in the opposite direction by the motive fluid.

' 65 34. In a pneumatic hammer,v a valve to -control the admission and exhaust of motive to one of its pressure areas through a portcontrolled by the piston, to cause the valve to admit motive fluid in front of' the piston to v drive the latter rearward, and being shifted in the opposite direction by air compressed by the piston at its backward stroke, to admit motive fluid to the rear end of the cylinder to drive the piston forward again.

35. In a pneumatic hammer, a differential valve to control the admission and exhaust of motive fluid to and from the opposite ends of the cylinder, said valve being moved in one direction by air compressed by the piston and in the opposite direction by the motive fluid.

36. In a pneumatic hammer, a differential valve to control the admission and exhaust of motive fluid to and from the opposite ends of the cylinder, said valve being moved in one direction by motive fluid admitted to the larger pressure area of the valve at the forward stroke of the piston, and in the opposite direction by air compressed by the piston at its return `stroke and acting upon the smaller pressure area of thevalve. l

37. In a pneumatic hammer, a valve to control the admission and exhaust of motive fluid to and from the opposite ends of the cylinder, said lvalve being located at the rear end of the cylinder and in line therewith and moved in one direction by air compressed by the piston and in the opposite direction by the motive fluid.

38. In a pneumatic hammer, a differential valve to control the admission and exhaust of motive fluid to and from the opposite ends of the cylinder, said valve being located at the rear end of the cylinder and in line therewith and moved in one direction by motive fluid admitted toits larger pressure area at the forward stroke ofthe piston, and in the opposite direction by air compressed by the piston at its return stroke and acting against the smaller pressure area of the valve.

39. In a pneumatic hammer, the combination of a cylinder, a piston therein, a valve for controlling the movements of the piston and having one of its pressure areas in communication with the rear end of the pistonchamber, means for admitting motive fluid to the opposite pressure area of the valve, and an exhaust-port for the rear end of the pistonchamber arranged to be closed by the piston during its return stroke to cause the air compressed by the furthermovement of the piston to shift the valve.

40. In a neumatic hammer, the combination of a cy inder, a piston therein, a differential valve for controlling the movements of the piston, and having its smaller pressure area in communication with the rear end of IOO IIO

IIS

ta-Wc) thepiston-chamber, a ort and passage leading ,from the piston-c amber to the larger pressure area of the valve and arranged to be uncovered by the piston at its forward stroke,

andv anv Aexhaust-port for the rear end of the piston-chamber arranged to be closed by the piston during its return stroke to cause the air com ressed by the piston during its further movement to shift the valve.

41. In a pneumatic hammer, a valve to control the admission and exhaust of motive fluid to and from the opposite ends of the cylinder, said valve being shifted in one direction by motive-fluid pressure at the forward movement of the piston and in the opposite direction by air compressed by the piston at its return stroke, and means for permitting a leakage of motive fluid into the rear end of .the piston-chamber during the return stroke of the piston.-

42. In a neumatic hammer, the combination of a cy inder, a piston therein, a valve for controlling the movements of the piston and having one of its pressure areas in communication with the rear end of the piston-chamber, a port controlled by the piston for admittin T motive fluid to the opposite pressure area ofthe valve at the forward stroke of the piston, an exhaust-port for the rear end ofl the'piston-chamber arranged to be closed by-th piston during its return stroke, and means for permitting a leakage of motive fiuid into the rear end of the piston-chamber during the return stroke of the piston.

43. In a pneumatic hammer, the combination of a cylinder, a piston therein, a differential valve for controlling the movements of the piston and having oneI of its pressure areas in communication with the rear end of the piston-chamber, means for admitting motive luid to its opposite pressure area, an exhaust-port for the rear end of the pistonohamber arranged to be closed by the piston during its return stroke, and means for permitting leakage of motive fluid into the rear end of the piston-chamber during the return stroke of the piston.

44. In a neumatic hammer, the combination of a cy inder, a piston therein, a differential valve for controlling the movements of the piston and having its smaller pressure area in communication with the rear end of the iston-chamber, a port and passage leading om the piston-chamber to the larger pressure area of the valve and arranged to be uncovered by the piston at is forward stroke, an exhaust-port for the rear end of the pistonchamber arranged to be closed by the piston during its return stroke, and means for permitting a leakage of motive Huid into the rear end of the piston-chamber during the return stroke of the piston.

45. In a neumatic hammer, the combination of a cy inder, a piston of uniform diameter therein, a valve for controlling the admission and exhaust of motive fluid to and from the opposite ends of the cylinder, and a passage leading from one pressure area of the valve to the piston-chamber and opening into the latter by a port uncovered by the rear end of the piston at 'the forward stroke of the latter, to admit motive iuid from the piston-chamber to said pressure area of the valve, and uncovered by the front end of the piston at the rearward stroke of the latter to ermit said motive fluid to exhaust into the ont end of the piston-chamber.

46. In a neumatic hammer, the combination of a'cy inder, a piston therein, a valve block or bushing at the rear end ofbhe cylinder provided with a series of ports and as sages communicating with the motiveuid supply, the front end of the cylinder, the atmosphere, and the rear end of the cylinder, respectively, and a valve operating in said valve block or. bushing and having along its length two grooves or recesses for governin said series of ports, said valve having one encgl exposed to the rear end of the iston-chamber and its other end in communication with the piston-chamber through a port controlled by the piston.

47. In a pneumatic hammer, the combination of a cylinder having a piston-'chamber and ports for the admission and exhaust of the motive iiuid, means for closing the rear end of the chamber to form an air-cushion therein, a valve for controlling saidl ports and arranged in rear of the piston-chamber, the inlet-port openin into the piston-chamber at a point forwar of the rear end thereof so as to form an air-cushion therein, and a piston operating to close said inletort on its rearward stroke and be cushione rapped in the rear end of the piston-cham- 48. A pneumatic hammer having a cylinder with ports and passa es for the admission and exhaust of motive opposite ends, and a permanently-open supp emental exhaustort located intermediate the len th of thecyhnder in osition to be uncovere by the rear end of t e piston shortly before the forward end ofthe piston-stroke, to thereby exhaust the motive fluid behind the piston, and to be uncovered by the front end of the piston shortly after the initiation of the return piston-stroke, to thereby ex'- haust the motive fiuid in front of the piston.

49. A pneumatic hammer having a cylinder with ports and passa es for the admission and exhaust of'motive uid to and from its opposite ends, and a supplemental exhaust port and passa e controlled by the piston and arranged to ex aust the cylinder on opposite sides of the iston, said supplementa passage extendin from the iston-chamber rearwardly an longitudinal y through the cylinder-Wall to the main or regular exhaustport adjacent the rear end of the hammer.

IOO

by the air uid to and from its we@ a3.-

50; A pneumatic hammer having a cylin- I der with ports and passages for the admission and exhaust of motive iluid to and from its opposite ends, a valve for controlling said ports and passages, and means for exhausting the front end of the cylinder independentlyL of the valve before the piston approaches the rear end of its stroke.

51.v A pneumatic hammer having a cylinder With ports and passages for the admission and exhaust of motive fluid to and from its opposite endsa,valve for controlling said ports and passages, and means independent of the valve for exhausting the cylinder on opposite sides of the piston at the rear end of its forward stroke and near the beginning of its rearward stroke.

52. A pneumatic hammer having a cylinder with ports and passa es for the admission and exhaust of motive uid to and from its opposite ends, a valve controlling said ports and passages and moved in one direction by air compressed by the flpiston and in the other direction by motive uid controlled by the piston, and means for exhausting the front end of the cylinder independently of said valve. Y

53. A pneumatic hammer' .having a cylinder with ports and passa es for the admission and exhaust of motive uid to and from its vopposite ends, a valve controlling said ports and passages andmoved in one direction by air compressed by the iston and in the other direction by motive uid controlled by thepistonhand means independent of the valve for exhausting the cylinder .on opposite sides of the piston.

54. A pneumatic hammer having a cylinvopposite ends, and a valve controlling said ports and passages and having at its front end a piston-head governing the admission of the motive fluid to the rear end of the cylinder, said piston-head being arranged to permit leakage of the motive fluid to the rear end of the cylinder when the valve isin position to otherwise cut off the supply of motive fluid thereto.

56. In a pneumatic hammer, the combination of a cylinder, a valve-bushing having ports and passages for the admission and exhaust of motive fluid to and from the cylinder, said bushin having a circumferential groove located adjacent the rear end of the cylinder and containing a constant supply of motive fluid, a valve operating in said bushing and controlling said ports and passages, and a constantly open but restricted passage between said groove and the rear end of the cylinder.

JAMES A. CARR, WILLIAM P. CARR.