US1590269A - Automatic safety device for pneumatic hammers - Google Patents

Description

June 29 1926.

2 Sheets- Sheet l C. B. WADE AuToMATc sxggfngnc Fon PNEUMATIG HAramBRs 'Y -ys/a.

.lu-ne 29 1926.

C. B. WADE AUTOMATIC SAFETY D-EVICE FOR PNEUMATIC HAMMERS Filed March 22, 1924 2 Sheets-Sheet 2 which controls the inlet Patented June 29, 1926.

unirse stares insane Partnr trice.

CHARLES B. VJ'ADEV, OF'ROANGKE, VIRGINA.

Application filed March 22, 1924. Serial No. 701,159.y

My inventiourelates to a safety device used on pneumatic hammers of any description such as riveting, calking and chiseling hammers, and the like.

In hammers of this class, the bit inserted at the operating end of the hammer fits loosely therein so that in case the pressure on the bit is momentarily released While the trigger is still held to admit pressure fluid into the hammer, it often happens that the bit is thrown out violently from the hammer, thereby causing serious accidents.

The main object of the present invention is to furnish an automatic safety device which closes the inlet port for the pressure fluid into the pressure chamber of the hammer immediately the bit is moved away from the Work independently of whether the trigger actuating' the throttle for admitting pressure fluid into the hammer is released or not. Accordingly, the plunger Vin the hammer will immediately be stopped against the bit so that the latter cannot fly out from its seat. p

ln some pneumatic hammers of late lconstruction an operating rod is furnished abutting the collar on the bit at one end and at the opposite end in Contact with a valve sure chan'iber. This valve is installed in axial alinement with the operating rod with the consequence that the pressure fluid *.vill act directly on the contacting end thereof and push the rod hard against the bit, and the operator will have to overcome this additional pressure when he applies the hammer against the work.

This disadvantage is entirely removed from the safety device forming the subject matter of the presentY invention, so that the operator does vnot have to use more force than with an ordinary pneumatic hammer Without such safety device.

In the accompanying drawings,V Figure l is a fragmentary side elevation and partial With a preferred axial section'of the hammer construction of the safety device; Figure 2 is a side elevation section of some of the details;

Figure 3 is a top plan of the safety device:

Figure 41s a bottom same;

and not driven port in the air pi'esand partial view of the casing or valve block containing the main parts.

plan view of the f Figure 5 is a vertical section along line 5&5 of Fig. 3;

Figure 6 vis a similar section along line 6-5 of Fig. 3; i

Figure' is a sidey for saidcasing.

Figure 8 is al fragmentary vertical section of the hammer with a slightly modified form of safety device; f

Figure Sis a top plan view, corresponding to Fig. 8, of the casing used in the modified form shown in Fig. 8, and u Figure l0 is a fragmentary sectional view of the upper end of the liaminershowing still another modification. Y V

Fig. 1l is a detail section on the' line ll-ll of Fig. l.

ln the drawings, Vreference ruimer-al represents the cylinder of a pneumatic hammer and 16 is a bit vmounted in the usual manner in the lower end of the cylinder l5 and retained therein by a clipV 17 permitting a slight reciprocatio-n of the bitin relation to the cylinder. The upperend of the cylinderl is threaded as at 18 in yorder to receive a head 19. This head is provided with a conventional handle 2O in which a fluid pressure passage 2ll containing the usual throttle with 'a groove or port 23 opening through the flat roof 2st of the' head Vinto the Working cylindrical pressure chamber of the hammer. lu the upperend of the cylinder is the usual sleeve 26 which tstightly on the shoulder 2'? ink thepressure chamber and houses the plunger, the pressure fluid. exhausting from the sleeve in the usual manner. ln or er to accurately seat the sleeve in the cylinder l5 and prevent it from turning. the lower end ofthe sleeve is provided With a-dowel 28 adapted to engage a corresponding .recess shoulder 27 of the cylinder. The upper end of the sleeve' is similarly 'provided with dow'els 30,' the functioning of which will be described later. The construction thus far described is Well-known andconstitutesV no part o-f my present invention'. i

elevation of a bushing l'Along one side of the cylinder l5 is guide 3l extending the' formedv a tubular I entire length thereof and opening at its loivei-,end above a collar valve' connects a supply hose 22.

29 furnished in theV n 32 onthev-bit 16.`` Above the shoulder 27 the guide is conl tinu'ed half ofit, as at 38, being furnished in the side of the sleeve 26, see particularly Fig. 2. The upper end of this guide is enlarged, as at 34, toaecommodatemthe on the lact-uating-rod '36 jwhiei'i v sf'slidfably in the guide with its extreme loive'fr end restingupon the collaiI 32 of the bit`16,.

As indicated'in Fig. 4{yt-lie upp'erfend `-of the cylinder 1.5 continues abovethe top end of the sleeve 26, and kinthe end f tl'ie"cyl-` inder between the endof thepsleeve.,andthe roof 24 of the head 19 is inserted a 4cylindricalj'plugyor valve block withflat top and the bottom side. offwhieh is is closed by a cap 42 preferably threadedin to thefvalve block against Concentric with the bore 40 are yemlnterbores `or annular 44 the former of 'which is positioned centrally therein, that 'iis' toV say, substantially in theaXial-,plane of the valve block and the cylinder 15. The'. other-groove isvadj acent tliejopen end of the bore. tersecting at right ga1-1g-le's' `withtheI bore 40 is drilled `a transversepaseage 545i-fthe open bushing. provided two grooves 4.3 and :endsv of'which-are -close'dby l'tight fitting plugs 4,6. From this transverse-rpassageextendfupwardlyto :the top "facenof the housing 3?, two ports47 adapted to register with theportsV 23 itheghammerhead '19.. In the bottom Y fae'ef'48 ofthe 'valve block 37 "iscut an annularfgroove 49,- the outer diameter of which' "is substantially the sanefas the ldistance between the outer@ walls Aof-.the ports 47 Yin the top of the `block. tablish communie ation `between this annular groove 49 and the transverse bore 40 Ea passage 50 is pr'ovided between the two, see sparticularly gigs. 4V and f6. :Thei enlarged porblock 37, half; ofthisl extension 522being1cut in the valve-block'and'the otherhalf inthe Depending "on: the length ofV cylinder-*15. the bushing I41the innemend -of the -latter will also? be eut out, as'at"`53,'1infFig., in head 35 l.-'ofv vtheactuating"rod order y thatthe 36 will be able to'freely"reciprocate in the guide. Inorder to'faeilitate manufacture,

through theytop ofgefthevalve blovelzSLf/as seen inFigs L 2`1and: "3 and 'thegpenendpf had 35,

'In `forder to eswall thereof and the valve block 37. The

reason'for furnishing this plug 54 is to provide an abutmentlforthe upperend of the lieadf' ofthe actuating rod'to limit its upward movement. y

VIn the bushing 41 is mounted to recipro- `-cate yav'alve plunger `55 between which and theL cap 42 `is inserted a compression spring "56,'s"e`eFig."l. 'This plunger has a head 5T,

neek 58:-.and5pabase 59, all integral parts. A seat is furnished in the bushing 4l forthe tapered end of 'the-base L59 ofthe valve-plunger-. This forms a tight `joint when the 4valve plug -is pressed into'the seat by the spring 56,V thus vpreventing all leakage forward ofthe base, that is to say,from the inlet ports 63 to the outlet ports 64. In'y ordergto take care of fany leakage tothe :rear ofthe -valvephuiger :and lpermit escape of air -whieh would otherwisehe compressed -by the opening movement of 'the val-vez and preventy itsfcomplete opening, a small air ventor exhaust passage 74 .is provided in the cap 142.and continued through thewalls of the cylinder v15 and the head 19. The head has-'a tapered nose 60adapted-toregister with fthe correspondingly beveled upper 'end ofuthe lactuating krod head 35, as Ibest 'seen in Fig.

- The bushing -41 isi-provided with vtwo exter- vnalfannular grooves 61 and 62, shown most ole'arlyfin Fig. 7, which register Vwith the annularfgrooves 48 and A44 ,respectively int the valve-block. .Communicating withi'the interior of the bushing 41 are radial ports y 63 "andf 264m :the grooves 6lrk :and 62 respectively formed, 'through the wall off the bushing *41. A'lhesrelative :positions of 'these ports are such that vwhen'the yplungervalve .55 fis iny a clos'ed fposition, as indicated-in Fig.jl-,-thegports 63 will be closed by the base 59""of the plunger -while theuports k64 remain constantly open 'whetherthe valve is in forn ward or retracted position.-

The operation of the device' is as follower f During"transportation"or when f the hainmer is Anot :in 1"actual use, the f position vof the parts is as shown in l, that-is teeny" vthe'jbiti"lr'is infits 'outerm'ostf position land the actuat1ng1rod36 rests vrwith.' its I'lower end against `Vtheieollar 32. i This iseau'sed" by the pressure y'of the'spring '56I against' the plunger valve '55wherebyfzthebevel nose 60eonipels the bevel head tomove downwardly. `=It willY be evident'fthat even if the trigger 65 be preseedYdown-to 'lopen the throttle. valve in "the l' passage" 21', "therebyf admitting f pressure fluid intoithe" Orts 23, this-pressure fluid canfrpass 'no ffurther -becausel the 59 of the )valve :plu'nger''eloses fup'onf the se at "175': and 'across Ath'e ports VT68, in 4lthe' bush- `upper Vbeveled end of the rod will ni'ove groove 49 in the valve block, whence it enters' the sleeve 26 to actuate the hammer plunger or piston in the usual manner.

In Figs. 8 and 9 is shown a modiicat-ion consisting in providing a central. aperture 66 in the valve block 67 instead ot the two side ports Ai?, although obviously al three ports may be used if desired. lo register with this central aperture 66, a corresponding aperture 68 is provided in the head 69 Communicating with the fluid pressure passage 70 in the latter. he operation et this inodilied device is identical with that ot the preferred form of the device, the only di't terence being that the pressure Huid enters centrally into the. bushing 7l.

ln File". l0 is shown still another modification ditl'ering from the two forms already described only by providing a valve block 7 2 of a diameter corresponding to the threads 18 on the cylinder l5. ln this case the hammer head 19 may be built slightly longer so that the block 72 rests` as before, on top ot the sleeve 26 which projects slightly above the threaded end ot the body cyl inder l5, as indicated in this figure.

The main reason for furnishing a bushing is to facilitate repairs as the bushing` is eX- posed to constant wear and it is evident that, depending upon the material used tor the valve block, the valve plunger 55 may be inserted directly into a bore furnished in the block without the ii'itermediary of a bushing.

It is also evident that in some cases the head 19 itself may be constructed to receive the valve plunger 55 although such construction would somewhat increase the cost oi manu-facture and prevent easy replacement of parts. As shown in the drawings, it will be clearly understood that this safety device can be applied very easily to existing hammers all the parts needed for the same are included in the valve block 37 with the exception ot the actuating rod 36 for which the guide 31 would have to be drilled in the hammer body.

The term bit in the specification and claims is intended to include any hind of punch, rivet set, chisel or other specific tool operated by a pneumatic hammer.

From the above description and the showing` of the accompanying drawings it will be evident that this device has still another advantage, namely, that it is immaterial in what angular position the head engages the threaded upper end of the c},flinder, because the valve block 37 is keyed in the chamber 25 through the intermediary ot the sleeve 26, which will always cause the guide poi tion 52 in the block to register with the corresponding guide portion in 'the cylinder l5.

Having thus described the invention, what is claimed as new isi Y l. rlhe, combinationv with a pneumatic hammer includingI a c flinder, a bit mounted in one end oi the cylinder and a handle at the opposite end of the cylinder having a passage for conveying pressure fluid to 'the cylinder, of a controlling` valve inounted transversely to the cylinder between the saine and the handle, yieldable means holding the controlling valve norn'ially in. closed position to cut oit flow oi pressure fluid to the cylinder, and a slidable actuating rod mounted longitudinally in the cylinder with i one end in contact with but free of the bit and its opposite end bearing freely against the end of the controlling valve in opposition to said yieldable means whereby to open said controlling valve when the bit is pressed against the work.

2. The combination with a pneumatic hammer including a cylinder, a bit mounted in one end of the cylinder, and a handle at the opposite end of the cylinder having a passage for conveying pressure fluid to the cylinder, of a plunger valve mounted slidably across one end of the cylinder between the saine and the handle, an expansion spring bearing against one end of said valve to hold the valve normally in closed position cutting Voti flow ot pressure fluid, and a slidable actuating rod mounted longi tudinally in the wall of the cylinder with one end bearing upon the end oi' the plunger valvey remote trom the spring and acting in opposition to the spring and its opposite end in contact with the bit whereby to open said .valve when the bit is pressed against work,

3. The combination with a pneumatic hammer including a cylinder, a bit mounted in one end of the cylinder, and a handle at the opposite end ot the cylinder having a passage for conveying pressure fluid tc they cylinder, ot a plunger valve mounted slidably across one end of the cylinder between the same and the handle, an expansion spring` bearing against one end of said valve to hold the valve normally in closed position cutting oilC flow of pressure fluid, the opposite end of said valve being beveled and a slidable actuatingl rod mounted longif tudinally in the wall of the cylinder with one end beveled and bearing upon the beveled end of the plunger valve and acting in opposition to said spring and its opposite end in contact with the bit whereby to open said valve when the bit is pressed aga-inst work.

et. The combination with a pneumatic los llt)

CAB

hammer' including a cylinder, -a ybit mounted in one end ofthe cylinder, a handle at the opposite end Aof the cylinder having a passage 'for conveyingpressure liuid to the cylinder` and a sleeve in the cylinder, el`

a Valve block held lixedly in the end of the cylinder byand between the handle and the sleeve, a eontrolling valve mounted slidaloly in the valve blocl transversely to the cylinder, yieldable means housed inthe Valve bloel: and acting onv said valve to hold it normally closed to Cut olil flow of pressure luid, and an actuating rod mount-ed'slidably longitudinally between the Walls o'l` the cylinder and the sleeve with one end vbearing upon the Controlling Valve in opposition to said yieldable means and its opposite en( in Contact with the bit whereby to open said Valve When the bit is pressed against work.

5. The Con'ibination With a pneumatic hammer including a cylinder, abit mount ed in one end of the cylinder, handle at the opposite end of the cylinder having' a passage for conveying pressure 'fluid to the cylinder, and a sleeve in the cylinder, ol a valve block held in the Vend oi i'heioylinder by and between the handle and the sleeve and having inlet, doWels on the ends of the sleeve engaging in apertures in the body of the cylinder and in the lower side oil-the valve bloel; respectively whereby to los; VJthe valve block against turning. a eontrollinrr Valve mounted*` slidably in the valve bloei( transversely to the Cylinder, yieldable means housed in the valve bloek and acting on said valve to vhold it normally olosedto ,out od flow of pressure fluid, and an actuating rod slidably mounted longitudinally between the Walls of the cylinder and the sleeve with one end bearing upon the controlling valve in opposition'to the yieldable means and its V opposite end in Contact with the bit whereby to open said Valve when vthe bit is pressed against work.

.6. lThe combination with a pneumatic hammer including a cylinder, a bit mou-nted in one end of the cylinder, and a handle at the opposite end of the cylinder having a passage lior conveying` pressure fluid to the cylinder, ot' a slidable Controlling valve mounted transversely to the cylinder Ybetween the sameV and the handle, yieldable means acting upon one endolz said valve to hold the saine normally in closed position cutting' ofi llow of pressure fluid to the oylinder,` and means `mounted upon the Cylinder operatively enffaged rwith the bit :and said yalye and acting upon said valve in opposition to said yieldable i'neans whereby yto open the vvalve when the bit .is `pressed against Work.

7. The combination with a pneumatic hammer including a cylinder, a bit mounted in one end of the cylinder, and aihandle secured on the opposite end of 'the-cylinder and having apassage for conveying pressure lluid to the cylinder, of a Valve block secured in the dast-mentioned .end not `the cylinder :against 'the `handle and provided with ports in its top communicating with the passage ir the handle ,an outlet inthe bottom ot' the Val-ve vblock for discharging lluid into lhe cylinder, and a diametriea'l bore in eonnnunieation with said ports and sae outlet., a yalveslic'lahly mounted usaid bore andhavingv a tapered head at oneend, yieldable means for holdingthe :valve lnormally ao-ross the ports in-the .atop 'of 'the Valve hloel with its'tapered f,head projectingthrough ythe side of the block, and a roc slidably mounted in the -Wall of the cylinder With one end resting, against the vbit and its opposite' end tapered 4and resting upon the tapered head-of the Valve whereby -to .aotuate the valve in opposition to the yieldable means when' the bit is pressed to its work.

In testimony Whereolaliix my signature.

CHARLES n. wenn. [ns- 1

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