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Publication numberUS904725 A
Publication typeGrant
Publication dateNov 24, 1908
Filing dateDec 20, 1906
Priority dateDec 20, 1906
Publication numberUS 904725 A, US 904725A, US-A-904725, US904725 A, US904725A
InventorsCharles B Richards
Original AssigneeCleveland Pneumatic Tool Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
US 904725 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)



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Specification of Letters Patent.

Patented Nov. 24, 1908.

Application filed December 20, 1906. Serial No. 348,708.

To all 'iv/mm it ma ,1/ concern:

Be ity known that I. (lnAuLns l. Rlcnauos, a qitizen of the United States. resident ot' Cleveland, county ot' (luyahoga. and State of Ohio, have invented certain new and useful ln'iprovements in ln|p:ut-.l`ools, ot which the following is ay specification, the principle oithe invention being herein explained and the hest mode in which l have contcmplatml applying that principle, so as to distinguish it from other inventions.

The annexed drawing and the following description set forth in detail, one mechanical form embodying thc invention; such detail construction being but one of various mechanical forms in which the principle otl the invention may be used.

Said annexed drawing represents au axial section of a pneumatic unpacttool embodying my invention.

The present embodiment oi' my improvements herein disclosed is an impact tool ot' the so-called valvelcss type. in which the rcciprocating plunger which impacts upon the shank of the working-tool acts as a distributing valve to control the distribution ot' the motive fluid to reciprocate the plunger.

The particular type of impact tool herein disclosed is a. so-called plug-drill, that is, an impact tool in which the impact of the reciprocating plunger is delivered to a stone,- drilling bit for the purpose of drilling holes in stone or similar substance to admit of thc insertion of wedges for cleavage, lewis-pins` for the attachment ot' hoisting devices, or for similar purposes.

A further improvement disclosed in the present impact tool resides in the provision of means for conducting a continuous stream or jet of live-air down through the drill-bit and into the hole in the stone for the purpose of mucking the drilled hole, that is, blow` ing out the dust or debris produced by the drill-bit in drilling the hole in the stone.

It Will be evident to any one familiar with the art to which this class of tools belongs, that the construction of the barrel and plunger of the tool may be employed in other impact tools besides plug-drills, and that also the device for conveying fluid under pressure through the drill-bit may be applied to other forms of rock-drilling tools besides the specie form herein disclosed.

`The tool has a barrel, 1, the upper or inner end of which is externally screw the diameter threaded t'or the attachment of a grasping and manipulating handle, Q. which in the present instance is illustrated in the form of a spade-handle, although it` may, of courstp, he ot' any other desired or convenient form. 'lfhe lower or outer end of the barrel has a. hore. il. into the lower or outer part of which a tool-nose, t, is secured. The axial bore ot' thisl tool-nose is polygonal and serves to receive and hold the polygonal shank, 5, of the drill-bit or other working-tool. At the upper end ot the bore 3 is formed an Aannular shoulder or rib, (i, so that. a cylindrical chamber is formed between the upper or inner end of thc tool-nose or socket and said shoulder. A cylindrical striker, 7, has play within this chamber, and is formed with a circumferential annular groove, 8, and with a nose or projection, 9, upon its upper end andadapted to be struck by the reciprocating plunger. 'lhe striker is formed with an axial bore, 10, extending from its under side up into the body ot the striker and then by a lateral channel`r 11, out into the bottom of the circumferential annular groove.

.\ port, 12, is t'orlncd in the side of the i striker-clmmber so as to register and communicate. with the circumferential groove of the striker in whatever position within its chamber the latter may be` and this port communicates with a channel, 13, in the Wall ot' the hammer-barrel. which channel eX- tends into and communicates with the liveair inlet. 14, t'orined in the side of the barrel a short distance above the middle of the same and at the`middle of the plunger-chalubcr within the barrel. The lower end of the pllinger-chamber, above the annular rib or shoulder 6, is formed into a large-diameter chaniher, 15, having one or more exhaust-ports, 16, through its wall out into the atmosphere. A smaller-diameter chamber, 17, is formed between this exhaustchamber and the point. in the plunger-chamber at which the live-air inlet enters 'the plunger-chambcr, at. which point. the dialnetcr of the'pltlnger-chandail' is enlarged to torni a piston-elmmber` 1S, which extends up to a distance Jfrom the upper end of the plunger-chamber, where it is again enlarged to 'form a live-air chamber, 19. A two-diameter or differential plunger, 20, reciprocates within the plunger-chamber, and is for the greater portion of its length of of the small-diameter portion of the saine. The upper portion oi the 1 employed.

plunger is formed with a piston, 2l, which is of the diameter of and reciprocates within the piston-chamber 18. Slots or grooves, 2Q,

are milled or otherwise formed at points in the circumference of the plunger and londitudinally extend from a point in the smalldiameter portion of the plunger a distance below the piston of the saine to point in the piston near the upper end of the plunger. The plunger is formed with an axial bore, 23, which extends from the upper end ot the plunger and down for the greater 'part ot the length of the same7 where such bore is intersected by a number of exhaust-ports, 24, radiating from the lower end of the boie and out through the sidi of the plunger7 so as to connect with the exhaust-chamber in the lower portion of the plunger-chamber when the plunger is at the lower end of its down-stroke. The drill-bit is formed with an axial bore, 25, which registers with the axial bore 10 inthe striker and entends to the cutting end of the drill so as to conduct live-air to such end or point and into the bottom of the drilled hole so as to blow the debris out ot the same.

ln practice, the live-air inlet is connected by means. of a suitable pipe or nipple to a hose or other flexible connection which conveys the motive uid to the toch-such motive fluid beirg in a majority of cases cornpressed air, while it is evident that steam or other elastic fluid under pressure may be lf the plunger is in the position illustrated in the drawing, the live-air will pass upward in the space between the smalldiaineter portion of the plunger and the sides of the piston-chamber in the barrel and will pass to the up er end of the plungerchainber through tie longitudinal grooves in the` plunger, so as to drive the piston downward to deliver its blow upon the f striker and through the same upon the end of the drill-shank.

It will be seen that by having the live-air supplied to the upper end of the plungerchamberthrough the longitudinal grooves, an ample supply of live-air will thus be provided to ldrive the plunger down and the hammering power of the impact tool will be comparatively great for a .'alveless tool. When the plunger has reached the lower end of its stroke, the exhaust-ports leading from the axial bore in the plunger will coinmunicate with the exhaust-space l5 in the plunger-chamber7 so that the live-air above the piston may escape through the exhaustport or ports in said chamber,.he admission of air above the plunger having been cut od when the upper ends of the longitudinal grooves in the plunger have passed below the shoulder formed between the upper most enlargement et the plunger-chamber, l which vmay be termed the live-air chamber, l

costas and the upper end oi the piston-chamber 18, so that the last portion of the downward strolre olf the plunger is accomplished by the expansion ot the live-air back of or above the plunger'. As soon as the air above the plunger has been exhausted and its pressure reduced, the constant air-pressure upon the small-area lower tace ol the piston 2l upon the plunger will again raise or force the plunger upward until the longitudinal grooves in the same communicate with the live-air chamber in the upper end of the barrela when the plunger will again be driven downward to deliver its blow. lt will thus be seen that the plunger is reciprocated by alternate admission and exhaust of live-air chamber in the upper end ot the plunger, and by a constant air-pressure upon a small-area piston-surface upon the plunger. rlhis provision for reciprocating the plunger .Greatly simpliies the provision for distributing the motive tluid in this impact toola and consequently simplifies construction -with accompanying strength of structure, and edecting economy in the cost or' construction.

fis long as live-air is admitted to the tool, the same is passed through the passage down4 to the circumferential groove in the striker and through theannular passage in the latter into and through the passageiin the drill' bit, thus eiecting complete mucking of the drilled hole by the constant stream or jet oi live-air through the drill-bit.

'@ther modes of ap lying the principle 100 of my invention may e employed for the inode herein explained. Change may therefore be made as re ards the mechanism thus disclosed, provide the principles of construction set forth respectively in the ol.- lowing claims are employed.

l therefore particularly point out and distinctly claim as my invention :H

l. ,ln a valveless pneumatic impact tool, the combination with a barrel or workingcylinder having air inlet and outlet, of a dierential plunger reciprocating within said barrel or cylinder and having a smallarea piston-surface exposed to constant air pressure and a large-area piston-surface and formed with an axial exclusive exhaust-passage and with inlet-passages through the small-area piston-surface.

2. ln a valveless pneumatic impact tool, the combination with a barrel orworlringcylinder having air inlet and outlet, of a differential plunger reciprocating within said barrel. or cylinder and having a smallarea piston-surface exposed to live-air pressure and a large-area piston-surface and formed with an excllisive exhaust-passage from the large piston-surface and@ through the plunger and with a live-air passage coininunioating with theconstant Aair pressure through the small-area piston-surface.v

3. ln a valveless pneuniatir impact toolI` .ne combination with a barrel toi-meti with a plunger-chamber having an exhaust-chamber and exhaust-port at its lower end and a live-air inlet at its middle and having an enlarged piston-chanibe above the inlet and a further enlarged live-air chamber at the upper end ot' said piston-chamber, of a diffta'ential plunger fitted to reciprot-ate within the plunger-chaniber and havingan enlarged piston at its upper and to reciprocate within the piston-Chamber and fornietl with an exclusiv` longitudinal exhaust-channel open through the u )per end of the plunger and through the sitles of the lower portion of the sante and with a longitudinal live-air passage extending from below the Smallarea piston-surface to a point near the upper @ntl of the enlarged piston.

ln testimony that I claim the foregoing to be niy invention I have hereunto set my hand this 7th daf,Y of December, A. Dl 1906."


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4651833 *Nov 28, 1984Mar 24, 1987Emil Schenker AgPneumatic impact tool
Cooperative ClassificationB06B1/183