US1108834A - Pneumatic hammer. - Google Patents

Description

E. G, DETRICK.

, PNBUMATIG HAMMER.

APiLIoATIoN FILED SEPT. 25, 1913. v f

Patented Aug. 25, 1914.,

2 SHEETS-SHEET 1` mm, ATTORNEY B. G. DETRIGK. a PNEUMATIG HAMMER.

APPLICATION FILED SEPT. 25, 1913.

Patented Aug. 25 1914, Y

2 SHEETS-SHEET 2` IIIII WITNESSES ATTORNEY .EMMETT Gr. DETRIGK, F VCKS'BURG, MISSISSIPPI.

'PNEUMATIC HAMMER.

. Specication of Letters Patent.

Patented Aug. 25, 1914.

Application led September 25, 1913. Serial No. 791,803.

To all whom t may concern l -Be it known that I, EMMirri` G. DETRICK, a citizen of the United States, residing at Vicksburg, in the county of Warren and State, of Mississippi, have invented a new and useful Pneumatic Hammer, of which lthe following is a specification.

l, This invention has reference to improvements in pneumatic hammers, and is to be understood as useful for any purpose where av rapid succession of blows is desired.

' It is the object of the present invention to provide a pneumatic hammer structure of extreme simplicity and at the same time one that is reliable in operation and not liable to become disabled because of the presence I. of obstructing matter, since the device of the present invention is largely self cleaning and is free from allcomplicated parts.

ln accordance with the present inventionthere is provided a freely reciprocable plunger or hammer designed to deliver a succession of blows to a suitable tool or tool holder and the body of the structure has certain ducts and ports to which the hammer is relatedA as a reciprocable valve, while the exhau'st is always freely openand hence oers n o impediment at anytime to the escape of air. The structure is furnished with valves which, however, are' springless Iand respond solely to air pressure, and these valves are so related to the hammer that vthe air for reci' rocation of the hammer.

their operation is not afterward directed to the hammer, wherefore the full and direct force of the air is always utilizable for the tudinal section of a pneumatic hammer embodying the invention.l and showing .the plunger atthe termination of its act-ive stroke. Fig. 2 is a section on the line 2-2 of Fig. 1.` Fig. '3 is a fragmentary section similar to Fig. 2 and showing the hammer at the beginning of as active Stroke. Fig. i isa sec-tion on the line 4-4 of Fig. 1. Fig. 5 is a perspective view of a valve block employed in the structure. Fig. 6 is an end view of the valve block as seen from the opposite end to that shown in Fig, 5. Fig. 7 is a section on the line 7-7 of Fig. 4c. Y

Referring to the drawings, there is Shown an elongated body member 1 usually cylindrical in cross section and terminating at one end in a laterally expanded head 2. Extending axially through the body 1 is a bore 3 which may be of equal diameter throughout, and is laterally expanded into a counterbore et within the head 2. That end of the bore 3 remote from the head 2 contains a sleeve 5 having a longitudinal passage therethrough of smaller diameter than the bore 3, and this sleeve is designed to receive a stem 6 on the corresponding end of a tool holder4 7 such as is customarily employed in pneumatic hammers, the term hammer being used as comprehensive enough to cover the use of the tool of the present invention for any purpose to which it islap'plicable.

Extending longitudinally through Vthe body member 1 to one side of the bore 3 is a duct or passage 8 of a length equal to that of the bore 3 between the counterbore 4 and the inner end ofthe sleeve 5, but at one point this duct 8 is interrupted by a web or wall 9. The duct 8 has ports 10, 11, 12 and 13 opening therefrom into the bore 3 at respectively different points. The ports 11 and 12 are on opposite sides of the web or wall 9, while the port 10 is between the port 11 and the Ahead 2, and the port 13 opens into the bore 3 closely adjacent to the inner end of the vsleeve 5. On the opposite side of the body 1 or at any other appropriate point the body 1 has another longitudinal passage 14 of less length than the passage 8, and this passage has ports 15 and 16 opening into the bore 3. The port 15 is closer to the head 2 than the port 10 and the port 16 is located between theports 12 and 13 in the direction of the length of the body 1, but closer to the'port 12 than to the port 13.

At other points about the body member 1- are longitudinal ducts or passages 17 and 18, respectively, exterior to the bore 3, the passage 17 being as long as the passage 8 and provided at the end corresponding to the inner end of the sleeve 5 with a port 19 0pening into the bore 3, the ports 13 and 19 being located at about the same distance from the head 2. The passage 13 is shorter than the other passages and extends from the head 2 but a relatively short distance and at its inner end is provided with a port 20 opening into the bore 3 closer to the head 2 than the port 10. For convenience the passages 8, 14, 17 and 18 are disposed about the bore 3 in approximately ninety degree relation, but this is not obligatory. However, for reasons which will hereinafter appear, the passages 17 and 18 are arranged approximately diametrically opposite one to the other. The passage 18 is also provided at theend adjacent to the counterbore 4 with a port 21 opening into the bore 3.

Fitted to the bore 3 so as to reciprocate therein freely yet snugly, is an elongated hammer or plunger'22 having a reduced central ortion 23 producing a groove 24 cir cumfleirentially about the middle part of the plunger.

Seated in the counterbore 4 is a block 25 shown as cylindrical in form, although not necessarily so, but such form .is the most convenient vtol through the block 25 is a passage 26 having laterally expanded ends 27 each closed by aj'scre'w plug 28 and from each expanded portion 27 there .extends a'port 29, 30, respectively, in alinement with the respective passages v17 and 18, and constantly open thereto. Each enlargement 27 where it joins the corresponding end of the passage 26 is formed into a valve seat 31 yadapted to recei've a valve 32, 33, respectively, each having a stem 34 entering the passage 26, and these stems are 'ogsuch length that when one valve i is seated'the other valve is held away from its seat. rI rhe passage 26 at about a mid point communicates constantly with a pas sage 35 extending radially through the block 25 and opening at the periphery thereof and n'ear the outer end this passage 35 has a port 36 in line and constantly communicating with the passage 14.

' Extending through the block 25 in parallelism with the axis thereo'fis lanother pas# sage 37v in constant communication with the passage 8 where it opensinto the counterbore 4, while still another passage 38 is formed through the block 25 parallel with the axis'of the block to accommodate a'pin 39 having one end seated in asocket 40 ap*` propriately formed in the head 2, so that when the block 25'is lodgedwithin the counterbore 4 the pin 39 maintains itin proper position. The pin 39 is to be taken as typfor holding the block 25 in constant relation with the parts with which its passages communicate.

The head 2 is seated in a socket' member' 41 having a handle 42 formedon or secured 'thereto and the handle 42 need not di'er materi ally from handles as customarily provided for pneumaticA hammers. In the construct. Diametricallyv incassa drawings the exterior of the head 2 and the portion of the socket member 41 receiving the head 2 are shown as correspondingly screw threaded, but even in this particular the showing of the drawings need not be strictly followed. The head 2 has fo m d therethrough a radial passage 43 com n1- cating with au opening or port 44 rough the socket member 41 and the 'Ssages 43 and 44 are in line with the passage 35 and in constant communication t erewith. Since the parts may not alway/s lit accurately lthe inner wall of the head 2 is provided with a circumferential groove/f' 45 and numerous passages 46 are formed through the head in addition to the passage 43, while the inner 'control of a manipulating lever 51 on the handle 42, so arranged that when the handle is grasped the valve 50 may be opened thus admitting air to the passage 8. The valve 50 and its manipulating devices may follow the usual practice and hence need no special description. The socket member 41 is formed with a shallow recess 52 where coming in contact with the block 25 so that air entering the tool may be distributed certainly to the passage 3 Let it be assumed that in the state of inaction the parts are in the position shown in F ig. 1 with the plunger 22 against the stem 6 at the end of the bore 3 remote from the head 2. Under these circumstances-one of the valves 32 or 33 is seated, but it is immaterial which one this may be. The operator grasps the handle 42 and by pressure on the lever 51 causes `the openingv of the lvalve 50 and air under pressure is admitted to the passage 8, it being assumed that an air hose is connected to the socket 49. In the position of the parts assumed the port 1Q is closed or blanked by the corresponding larger end of the plunger 22 and the port 20 is also closed thereby, whilethe other larger end of" the plunger 22 closes the port 16. However,-

the ports 11`and 12 arein communication through the groove 22 then. bridging these ports, andthe port 13 is o ene to the bore 3 between the correspon" in l K y end.` of the plunger and the innerA end the y sleeve 5,

' 125 lthe plunger b einghel'd awayfromthe' sleeve, by a sllght -projection ofthe stem`6 into the' bore 3. Air undervpressure'therefore finds its way along,the 'passage 8 thrughthepor't into the groove 24 andfrom thence by 130 way of the port 12 into the continuation of the passage 8 on the other side of the web 9 and by way of the port 13 into the bore 3 and exerts its pressure upon that end or head of the plunger 22 at the time engaging the stem 6. The air under pressure also inds its way from the bore 3 through the port 19 into the passage 17 and from thence into the enlargement 27 containing the valve 33 and if at the time this valve is open, the air under pressure immediately closes it and at the same time causes the opening of the valve 32. The compressed air at once impels the plunger 22 away from the stem 6 toward the block 25 and this causes the progressive closing ofthe ports 12 and 11 and the ultimate opening of the port 10 to the groove 24. The initial movement of the plunger 22 is unimpeded because air within the bore 3 between the plunger and the head 25 finds ready escape through the port 15 into the exit passage 14 which is always in free communication with the atmosphere through the port 36, passage and passages 43 and 44. The plunger quickly closes the port '15, but still there is an exhaust passage for air within the bore 3 between the plunger and the block 25 by way of the ports 21 and 30, and the passage 26 where opened by the valve 32, said passage 26 being at all times in free communication with the atmosphere through the passage 35. The expansive force of the air is exerted upon the plunger to move it toward the block 25 until ulti- .air is under greater pressure than the air tending to hold the valve 33 closed, the latter valve is forced open and the valve 32 is closed, thus cutting off the escape of air from the bore 3 between the plunger and the block 35 before the plunger reaches the block 25, and, moreover, the rapidly diminishingk space within the bore 3 receives air under full pressure thro-ugh the port 21. Simultaneouslv with the establishment of the conditions just named the other end of the plunger has moved to a position to uncover the part 16 to the end of the bore 3 first receiving air unoler pressure, while the passage 17 always communicating by the port 19 *with the end of the bore 3 remote from the block 25 is now in communication with the atmosphere through the open valve 33. The rapid accumulation of air pressure between the plunger andtheI block 25 not only interposes a strongl air cushion preventing the plunger from reaching the block 25, but full air pressure at once acts upon the block 25 to drive it toward the stem 6 which it strikes with all the force imparted to it by the air pressurebehind it, for air pressure is not again established at the striking end of the plunger until the port 12 is uncovered, which does not take place until approximately the time that the blow is struck. Then,and then only, is there established an air pressure-sufficient to reverse the valves and returnV the plunger to the beginning of its power stroke.

The air cushion established between theV plunger and the head 25 at the termination of the retractive movement ofthe plunger Aprevents any shock or jar which might occur should the plunger strike metallic parts,'and also does away with the necessity of a buffer spring, while at the end of the power stroke the full force of the plunger is utilized with# out the retardation by the establishment of bufing pressure or the presence of a buiing spring. a

Experience has shown that the plunger will reciprocate at high speed, say, about two thousand strokes per minute, while the -power of the stroke is in excess of that of commercial forms of pneumatic hammers of like air consumption.

No springs whatever are used in the working parts of the hammer, the two valves employed being responsive solely to air pressure, and this air pressure is not weakened by performing work before it reaches the valves, nor does any ofthe compressed air do any work before reaching the plunger. Full power is therefore available for all the work performed and the parts respond vigorously and with full efliciency.

The passages and ports can be made of ex,- ceptionally large size, so that any particles liable to choke small assages, and which sometimes find access t creto, have nomaterial effect upon the device of the present invention and should small particles of grit or the like find their way into the passages and ports the plunger readily vforces them out on its return stroke. valves 32 and 33 leak to some extent, it only means a slight waste of air without a material reduction in the eflciency of thedevice.

All the ports through which the main air passes are controlled by the plunger and the `Even should 'the only valves other than the plunger itself opening into the bore on each side of the interruption, two other ducts each having a plurality of ports leading into thebore, with one of said two ducts opening constantly to vthe atmosphere and the other of said two ducts constituting both a live air and an exhaust duct, means responsive to live air bore said duct having its continuity linter-y mediately interrupted and provided with ports opening into the bore on each side of the'interruption, ,another duct shorter than therst-named duct and .provided with a plurality of ports opening .into the bore and saidduct also opening constantly to the atmosphere, another duct in the body member having a plurality of ports opening into the bore, a fourth duct extending longitudinally of the body member and communicating with the bore at the end thereof into which the first-named duct leads, and a valve structure located at the opposite end of the body member/and there communicating with the third and fourth named ducts, said valve structure being responsive to live air pressure su plied through the said ducts controllable t ereby and opening and closing said -Jducts'to the atmosphere.

3. A pneumatic hammer comprising an elongated body member with a longitudinal bore and a live air duct extending longitu-` dinally through the body member and at one end opening into the corresponding end of the bore, said duct having its continuityintermediately interrupted and provided withy ports opening into the bore on each side of the interruption, another duct shorter than the irst-named duct and provided with a plurality of ports opening into the bore and said duct also opening constantly to the atmosphere, another duct in the body member having a plurality of ports opening into the bore, a fourth duct extending longitudinally of the body member and communicating with the bore at the end thereof into which the first-'named duct leads, and a valve structure located at the opposite end of the body member and there communicating with the third and fourth named ducts, said valve structure being responsive to live air pressure supplied through the said ducts controlled thereby and opening and closing said ducts to the atmosphere, the valve structure comprising separate valves and Vincluding a duct constantly open to the atmosphereat an intermediate point and provided at op- `posite sides with' oppositely directed valve seats for the valves.

4. A pneumatic hammer havingf'an elongated body member provided with a longitudinal bore and with air ducts leading into the bore and spaced apart to direct `air under pressure into opposite ends of the bore, and one of said air ducts also leading t0 the atmosphere, the .body member being provided With an exhaust duct distinct from the velongated body member having an elongated bore, and a reciprocatory plungerftherein, saidk body member having air ducts with ports communicating with the bore and controlled by the reciprocatory plunger, certain of the ducts being arranged to receive live air-under pressure and direct it against opposite ends of the plunger with onev of the live air ducts leading to the atmosphere and another of the ducts serving solely as an exhaust duct, the device being provided with means responsive to air underpressure and arranged to be operated by live air other than that operating the plunger Ifor controlling the exhaust of utilized air.

6. A pneumatic hammer comprising an elongated body member with an axial bore and a reciprocatory power plunger within the bore, a closure for ,one end of the bore having a transverse duct therein with valve seats at the ends 'andintermediately communicating with the atmosphere,` valves mounted \in the duct in operative relation to the valve seats, ducts leading through the body member and having ports communicat ing with the bore and the ports and plunger' being related to cause the latter to operate as a controlling member for the ports, one of the ducts constituting a live air duct for supplying air under pressure, and another of the ducts constituting an exhaust duct at all times communicating with the atmosphere, and others of the ducts communicating with the valve in the closure to supply live air thereto for operating the valves.`

7. A device of the type described compris.u ing an elongated body member havingan axial bore, and a reciprocatory plunger mounted therein, said body member being provided with a duct for live air and having ports communicating with the bore, another duct having ports communicating with the bore and also' communicating with the atmosphere, a block forming a closure for one end of the bore, a reciprocatory valve structure within the block movable in a direction Jperpendicular to the longitudinal axis of the bore, and ducts in the body member communicating with the bore and with the valves, thereciprocatory plunger being re lated to the ports opening into the bore and b eing constructed to control the ports to regulate the admission of live air to the bore to drive the plunger, and the admission of live air to the valves to control their action.

8. A device of the type described comprising an elongated body member with an axial bore and with a counterbored head at one end, said body member being also provided with longitudinally extended ducts having ports communicating with the bore at different distances from the counterbore, a reciprocatory plunger lodged in the bore and constructed to operate as a reciprocatory valve for the ports, a block lodged in the counterbore and having ports equal in number to the ducts in the body member and each communicating with a respective one of the ducts in the body member, and a valve structure in the block responsive to air supplied through certain of the ducts, said valve structure controlling the exhaust of air from certain of the ducts and the plunger controllin the exhaust of air fromI the opposite ends o the bore.

9. A device of the type described comprising an elongated body member with an axial bore and having longitudinally disposed ducts in surrounding relation to the bore, one duct being provided with a break in its continuity at an intermediate point with ports, two on opposite sides of the break and leading to the bore, and one of the ports enterin the bore at one end thereof, another duct aving spaced ports entering the bore, and said duct being also provided with free communication with the atmosphere, another duct having a port communicating with the bore adjacent tothe end port of the firstnamed duct, and still another duct communicating with the bore at its opposite ends and of less length than the other duct, a block forming a closure for the corresponding end of the bore and provided with ports communicating with each of the said ducts in the body member, reciprocatory valves within the block and each controlling a respective port other than those communicating with the first-named duct and the duct connected to the atmosphere, the block also having a passage communicating with the atmosphere and controlled by the valves, and a plunger mounted in the bore to reciprocate therein and constructed to control the port opening into the bore.

10. A device of the type described provided with a reciprocatory power plunger and having live air ducts controlled by the power plunger for supply"Wr air under pressure to operate the plunger, said device being provided with other live air ducts and an air exhaust duct controlled by the plun ger, and an exhaust valve structure communicating with the last-named live air ducts for receiving live air therefrom and in turn communicating with the atmosphere to exhaust the said last-named live air ducts.

11. A device of the type described provided with a reciprocatory power plunger and lhaving live air ducts controlled by the power plunger for supplying air under pressure to operate the plunger, said device being provided with other live air ducts 'controlled by the plunger, and an exhaust valve structure communicating with the lastnamed ducts for receiving live air therefrom and in turn communicating with the atmosphere to exhaust the last-named live air ducts, an exhaust duct distant from the ducts controlled by the valve structure and wholly controlled by the plunger.

In testimony, that l claim the foregoing as my own, I have hereto affixed my signature in the presence of two witnesses.

HERBERT A/SPDEN, J. D. MoCAnRoN.

Copies et this patent may he obtained. for .ve cents each, by addressing the Commissioner n! Patents. Washingtom.

said device being also provided with`

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