US845905A - Percussive hand-tool. - Google Patents

Description

4 SHEETS-SHEET 1.

No. `845,905. PATENTED MAR. 5, 1907. H. B. STOCKS & J. R. WEBB, JR.

PERGUSSIVE HAND TOOL. APPLICATION FILED SEPT/28,1903,

TH: Numels Erg-Rs ca., wAsMlNaroN, n. cA

N0.'845,9o5. PATENTED MAB.. 5. 1907. H. B. STOCKS @E J. R. WEBB, lJR.

4 SHEETS-SHEET 2.

IERCUSSIVEA HAND TOOL.

APBLIOATION FILED sBPT.2s.19oe.

1H: Hormis PETERs co.. wAsmNcmN, D. c.

No. 845,905. PATENTEDMAR. 5, 1907. H. B. STOCKS n J. R. WEBB, JR.

PERGSSIVE HAND TOOL.

APPLIOMKIION FILED sBPT`.2a.19o.

4 SHEETS-SHEET 3.

1HE Namzls PETERS ca., wAsHlNafoN, n. x2.

No .F845

PATENTBD MABL, 1907. H. B. STOCKS & J. R. WEBB, JR.

PEROUSSIVE HAND TOOL.

- APPLIOATION FILED sEPT.2s.19o6.

4 SHEETS-SHEET 4.

UNITED STATES PATENT OFFICE.

HARRY BENWELL STOCKS AND JOHN RACKER WVEBB, JR., OF MANCHESTER,

ENGLAND, ASSIGN ORS TO THE CLIMAX PATENTS LIMITED, OF MAN- CHESTER, ENGLAND.

PERCUSSIVE HAN D-TOOL.

Specification of Letters Patent.

Patented March 5, 1907.

inclination filed September 28,1906. Serial No. 336,582.

.T (lr/ZZ whom t may concern:

Be it known that we, HARRY BENWELL STOoKsand JOHN RACKER l/VEBB, Jr., subtuated by compressed air in which a piston l or tup reciprocates within a cylinder, as 1s well understood.

Under our invention we use two continuous streams of air under pressure for the blow and return stroke, and we also employ a valve governing the admission of motive fluid to the piston of the hammer, such valve having a small area on which motive iiuid is constantly acting, tending to force the valve over in one direction, and a large area on which motive fiuid intermittently acts to move the valve at the required times in the contrary direction.

l/Ve are aware that the principle set out in the preceding sentence is not novel g but the essential novel feature of our invention, in addition to the particular construction and operation of .the valve and system of ports, consists in the employment of a continuous stream of'air under high pressure for the blow stroke and a continuous stream of air under low pressure for the return stroke, so that the hammer works economically and with an absence of vibration and shock or jar.

We may under our invention construct the hammer so that the air under high pressure is admitted behind the piston for the whole of the blow stroke, or with a modification in detail suchv air under high pressure may be cut o'lfwhen the piston has made but a portion of its stroke, the remainder of the stroke being worked by the expansive power of the admitted fluid. We could also use either air under high pressure or air under low pressure for constantly loading the smaller area cf the valve governing the admission of motive fluid to the tool.

l tion'of its blow stroke.

In the accompanying drawings, Figure l represents asectional elevation on the line A B, Fig. 2, of a percussive hand-tool constructed in accordance with our invention, in which the valve is loaded constantly on its smaller area with air under high pressure. Fig. 2 is a sectional plan thereof. Figs. 3 and 4 are respectively sectional elevation and sectional plan of a similar hammer, but provided with an expansion-valve to cut off air under high pressure when the piston has made but a por- Figs. 5 and 6 are sectional elevation and plan of a percussive lhand-tool in which a single valve only is used loaded constantly on its smaller area with air under low pressure; and Figs. 7 and 8 are similar sectional elevation and plan of a percussive hand-tool similar to Figs. 5 and 6, but provided with an expansion-valve.

It will be noted in the percussive handtools illustrated in the accompanying drawings like parts are similarly lettered to avoid repetition of description of these parts.

I/Ve will refer first to Figs. l and 2, in which the valve is loaded constantly on its smaller area with air under high pressure. The tool consists of a cylinder a., in whichis freely slidable a piston b, provided with an annular recess c at its rear end. The cylinder o is secured to the boss d of the handle c by means of a screwed nut f, bearing against a flange g on the inner end of the cylinder, the iange g contacting with a disk h, interposed between the flange g and a valve-box t', contained in the boss d of the handle e. The mouth of the cylinder a is provided with a bush to carry the end of a chisel 7c or other tool. The meeting faces of the end of the valve-box i and the boss d of the handle f are formed to provide concentric annular recesses m n. A tube 0, conducting air under high pressure, is secured to the inlet o in the handle, and another tube p to conduct air under low pressure is connected at p to thel handle. From 0 a passage g connects with the annular recess m, and a similar passage r connects p with the recess n. Each of the passages g r is governed by a piston-valve s, slidable in a chamber s', the lower end of which is closed by a screwed plug s2. A trigger t is mounted on a fulcrum a, the trigger being disposed between the valves s s. This trigger is provided with a horn o, through which and pro- ICO jeeting from each side thereof is a cross-pin w, disposed on the top ot the valves s s. Normally the air under pressure in the conducting-tubes is sutlicient to maintain the valves s s in the elevated position shown in Fig. l. When pressure is applied upon the valves 8 s by means et the trigger t, the valves are depressed, and communication is established between the passages o p and ports g r, so that air under high and low pressures is conducted to the annular grooves m n, respectively, the groove m containing air under high pressure and the groove n air under low pressure. distribution-valve is litted capable et a sliding movement to a certain extent. rlilis valve fr; is vformed hollow with exhaust-passages y `formed therein. lt is ot two dii'leu ent diameters to 'term a shoulder e, and also an annular groove 2 is provided near lie end in the smaller diameter. Ports are 'termed in. the valve-box i, communicating with tle high and low air-pressure recesses m n, witlthe valve x, and with ports leading to the front and rear ot the piston l). As shown in Fig. 2, the piston l) is at the inner end olt its stroke and the valve a; is in correct position to admit air under high pressure (assuming the valves s s to be depressedby the trigger t) to the b ack ot the piston tor the blow stroke. Air under high pressure is constantly acting on the small area .e of the valve such air und er pressure being admitted to tlc area e `from the groove m via the ports 3 and 4, forcing the valve a over into the position shown in Fig. 2. The reduced diameter ot tl'e valve Qc enables air under high pressure to pass to the port or ports 5 and from thence tltrough the hole or holes 6 in the disk 71y to tle back oit the piston l), actuating the piston tor tlte blow stroke, the residual air under pressure o'l the previous return stroke in trent of tle piston exhausting through the port 7 out ot the aperture 8 at the inner end ot such port 7, uncovered by tle valve x to the exhaustpassage 9 in the handle of the tool, and so to atmosphere. lhen the piston l) is just attaining the end ot its blow stroke, tlte annular recess c uncovers the entrance 10 to a port 11, which port 11 is then put into coml munication with the cavitym, containing air 'under high pressure, by means et the port f3,

so that air under high pressure is admitted to the tront or large area 12 ot the valve :11, overcoming the air under high pressure acting constantly on the small area e' and moving the valve ac into the position shown in Fig. 1 Air under low pressure can tlen pass trom the recess n tlirough the port 13 in tle valvebox i, around the annular groove 2 in the valve to the groove 18, and by way ol" the port S to the port 7 tlirou the hole 7l in tlc disk 71 and so to the `trent ot tl'ie piston l), returning the piston to the position shown in Fig. 2. On the return stroke of the piston l) ln the valvewbox i a eaaees residual air of the previous blow stroke is exhausted through the aperture or apertures (l in the disk 71. and the port or ports 5 to the annular groove ltytrom which it passes through the exhaust-ports 1 1/ through the hollow valve :l: to the exhaust S), and so to atmosphere. rlo enable the air under high pressure acting con stantly on the small area .z ot the valve a: to return the valve x to the position shown in Fig. tor the i'-.ext blow stroke, the port 1.1V is continued. forward and is provided with an outlet 13b into the cylinder c. This outlet 13h is uncovered when the piston l) is attain.- ing the end ot its return stroke, and the air under high pressure previously admitted to act on the large area 12 ot the valve a; exhausts into the cylinder a, bringing about sueh a reduction ot pressure against the area 12 o't the valve x that the air under high pressure constantly acting on the small area .e is en abled to move the valve a: over in the position shown in Fig. 2, and. the described cycle ol operations tor the blow and return strokes is repeated. The hammer is automatically self-starting, tor suppose when the air under di'tlerent pressures is admitted by the valves s s the piston l) should be in the position shown in Fig. 1 ,while the valve :I: is in the position illustrated by Fig. 2, the air under high pressure would p ass round the annular groove c in the piston l) and be conducted by the port 1 1 to the iront or large area 1.2 on the valve rr, toreing it back to the correct position shown in Fig. 1 to admit air u nderlow pressure Ytor the return stroke. (ln the contrary, should the piston l) be ready 'l'or the blow stroke, as shown in Fig. 2, and the valve a; be in the po sition. indicated. in Fig. l air under high p res sure, which constantly acts on the small area e', would as soon as admitted by the valve s ilorce the valve .r 'forward to the correct position illustrated by Fig. 2.

With a hammer constructed as described the air under high pressure is admitted behind the piston l) during the whole ot the blow stroke, but we may provide means, as illustrated in Figs. 3 and Ll, tor cutting o'llI the air rnder high pressure when the piston has made but a portion ot its stroke, so that the remainder ot the stroke would be completed by the expansive action ot the admitted air under high pressure. To ell'eet this, we provide the valve-box i with an expansionfalve 15, consisting ot a ring ot metal with equal areas 15" 15'y and 'formed with anii'iternal annular recess 1.6, the valve 15 being slidahle 'fluid-tight on a seat prepared Vtor it in lthe valve-box, as illustrated. Air under lovY pressure vtrom the port 13 acts eonstanlllv against the area 15h ot the valve 15, as will be seen trom an inspection ot Fig. its shown :in Fig. 4, the valve .r has been moved 'forward by air under high pressure acting constantly. as explained, on the small area e, and the v: lve 15 has also been moved forward by the air llO under low pressure. The air under high pressure is thus admitted from the ports 3 4 to the groove 5a, and by a port or ports 20 to the recess 16 in the valve 15 and a port or ports 21 to ports 22 through holes 23 in the disk h, and thus behind the piston b. When half or any other predetermined portion of the blow stroke has been completed, a hole 17 in the cylinder (see Fig. 3) is uncovered by the piston b, and the air under high pressure behind the piston enters a port 18 and is conducted by a passage 19 in the disk h to the front area 15a of the expansion-valve 15, forcing it back against the air under low pressure acting on the area 15b into the position shown in Fig. 3, and thus cutting off the supply of high-pressure air to the back of the piston b. The remainder of the stroke is thus completed by the expansive force of the admitted air under high pressure. The air of the previous return stroke in front of the piston b is exhausted through the port 7 to atmosphere through the exhaust-outlet 9, as already described with reference to Figs. 1 and 2. For the return stroke the valve is moved backward into the position shown in Fig. 3 by high-pressure air admitted to the ont or large area 12 of the valve via the ports 3, 1.0, and 11, as previously described when referring to Figs. 1 and 2. Air under low pressure is then admitted through the port `13 and annular groove 2 to the annular recess 13, to the ports 8 and 7, to the front of the piston b, returning the piston for the next blow stroke. On the return stroke of the piston l the residual airpressure of the previous blow stroke behind the piston b is swept out through the holes 23 in the disk h, ports 22, to the ports`21, and from thence through the holes 'y to the interior of the valve and so to atmosphere through the exhaust-outlet 9, as clearly seen in Fig. 3. f

It has already been explained, when referring to Figs. 1 and 2, how the air under high pressure acting on the large area 12 of the valve is reduced sufficiently to enable the valve to be forced forward by the air under high pressure acting constantly on the small area .2 of the valve in readiness to admit air under high pressure behind the piston b for the blow stroke and to exhaust the forward end of the cylinder a. In the construction shown in Figs. 3 and 4 it is necessary to also move the expansion-valve 15 forward again into the position indicated in Fig. 4. This is effected by providing the port 18 with an outlet 19EL into the cylinder a, such outlet being uncovered when the piston b has completed its inward stroke, so that air under high pressure admitted to the front area 15a of the expansion-valve is reduced in pressure by exhausting into the forward end of the cylinder a, which at this instant is placed in communication with the atmos- 5 phere by the forward movement of the valve l fr, as previously explained. Air under low pressure which is constantly admitted behind the area 15b of the expansion-valve 15 via the port 13 is thus venabled to force the expansion-valve forward to enable it to admit high-pressure fluid behind the piston b for the blow stroke.

We do not confine ourselves to the use of air under high pressure for constantly loading the small area of the distribution-valve as the air under low pressure used for returning the piston b within the cylinder a may be employed, as illustrated in the construction, Figs. 5 to S. In Figs. 5 and 6, which we will first deal with, no expansion-valve is used, the distribution-valve admitting air under high pressure behind the piston l) throughout the entire blow stroke. For the return Astroke the valve :v and piston l) are in the relative positions shown in Fig. 5. The valve is formed with two annular grooves 2 and 2a. Air under low pressure passes from the annular groove n along the port 13,-

around the annular groove 2a in the valve :c to the groove 13a, and to the port 7 to return the piston. Air previously supplied behind the piston is exhausted through the holes 6 in the disk 7L and ports 5 to the annular groove 14, and from thence through the holes y to the interior of the valve and from thence to atmosphere by the exhaust 9. As the piston attains the end of its return stroke the port 11 permits air under pressure on the large area 12 of the valve :r to exhaust into the cylinder a, and from thence by a hole 23 to atmosphere. This reduces the pressure on the large area 12 of the valve a: to atmospheric, or thereabout, and enables air under low pressure acting constantly on the shoulder or small area z of the valve to move the valve forward in the position shown -in Fig. 6. Thus air under high pressure can pass from the groove m through the ports 3 and 4, around the annular groove 2 to the port 5, and thus behind the piston for the blow stroke. The air under pressure of the previous stroke in front of the piston exhausts through the ports 7 and S to the exhaust 9, and sov to atmosphere. When the blow stroke is completed, air under high pressure is conducted from the port 3 around the annular recess c in the piston Z) through the ports 1.0 11 behind the large area 12 of the valve c, forcing it backward into the position shown in Fig. to admit air under low pressure in front of the piston b for the return stroke.

Figs. 7 and 8 show a similar hammer to Figs. 5 and 6, but having an expansion-valve constructed and applied in manner similar to that in Figs. 3 and 4. As shown in Fig. 7, the return stroke of the piston b and the exhausting of air under pressure behind the piston is effected as described with reference to Fig.5 and can be readily followed. Vhen IOO IIO

IIS

the piston l) has been returned. to the position shown in Fig S, air under pressure in front of the area 15 of the expansion-valve l5 and air under pressure acting` on the large area l2 of the valve fr exhausts into the cylinder e through the ports 1.1 1S, and fromY thence to atmosphere through the hole 23 in the cylinder, so that alr under low pressure acting on the rear area 15b of the expansion-valve 15 and also on the small area z ol the distribution-valve is enabled to move both these valves 'forward into the position shown in Fig. 8. The cylinder a, behind the piston l), is then open to admit air un der high pressure for the blow stroke, as will be apparent. Air under pressure in front of the piston l) is exhausted to atmosphere on the blow stroke through the ports 7, S, and 9. Vilben a portion ol' the blow stroke has been ellected, the air under high pressure admitted to the cylinder a behind the piston passes through the ports 17, 18, and 19 to the liront area 15a of the expansion-valve 15, 'forcing it b ackward to the position shown in Fig. 7 and cutting oil. the supply of air under high pressure, so that the remainder of the stroke is completed by the expansive pressure of the air under high pressure admitted behind the piston.

It will be understood that the motive [luid for the blow stroke may be air under any desired pressure in excess o'l' the pressure used lor the return stroke and the air under low pressure such as will be sullicient to promptly return the piston in the cylinder in readiness for the blow stroke.

The drawings show the inventirui applied to a percussive liand-tool, but the invention may be used with larger power-hammers aetuated by air under pressure.

We declare that what we claim is l. ln percussive hand-tools, power-hammers and similar tools in which a piston or tup is reciprecated to and fro within a cylinder, inlet-ports conducting two continuous streams ol air, one under high {nessure l'or the blow stroke and one under low pressure for the return stroke, in combination with a distribution-valve having two unequal areas, the small area being constantly acted upon by air under pressure and the large area being intermittently acted. upon by air under pressure substantially as described.

2. In percussive hand-tools, power-hammers and similar tools in which a iston or tup is reeiprooated to and 'lire within cylinder, inlet-ports conducting two continuous streams of air under pressure, one under high pressure for the blew stro re and one urder low pressure for the return stroke, iu combii nation. with a distribution-valve havin g two unequal areas, the small area being constantly acted upon by air under )ji'iji'essure and the large area being intermittently acted upon by air under pressure, with means lor cutting ell admission of air under high pres- `valve to lio'rm dill sure wlren the piston has made but a portion ol its stroke substantially as described.

ln a perrussive hard-tool, power-hammer or similarI tool, a cylinder, a pistou slidable within sueh cyliider, inlet-ports lor lu'o continuous streams ol air iuder dillereiu pressures, a valve-box, a hollow disl'riluuiouvalve el' unequal diameters slidable in such valve-box formed with exiiaust-passages, uuequal areas lormed on such valve to lorm dill'erei'ilial pressure areas, ports to conduct constantly air under pressure to the smaller pressure area ol" the valve, ports governed by the piston to conduct intermitlently air under pressure to the larger area el` tlze valve. an exhaust-port to atmosphere, 'ports liormed in the cylinder comniuuicatiizg with the distributioii-valve and valve-box, substaiitially as desoribed.

l. ln a percussive hand-tool or the like. a cylinder, a pis i slidable within suoli cylinder, inlet-ports 'lor two continuous streams et air under dill'erent pressures, a valve-bex, a hollow distribillion-valve el unequal diameters slidable therein lormed with exhaustpass'iages, unequal areas 'formed on sucia Iereul'ial pressure aras. ports to conduct constantly air under pressure to the smaller areay ol the valve, pons governed by the pil. in to conduct intermittently air under pressure to the larger at ol the valve, an expansioir-valve slidable in l ee valve-box, ports to eoiiduct air under low pressure oorustantly to one atea olt the expansion-valve, ports governed by the piston to oonduet air urder high pressure iulermitently to the other area ol the expansionvalve, an exhaust-port to atmosphre, ports formed in the cylinder eommuuiealing with the valves, and valve-box, substantially as deseri bed.

5. A pou/er-hamn'ier consisting ot a evliuder, means `for carrying a tool in the nuiui ii el the cylinder, a piston slidable in. the \linzler, a recess formed in the rear end olA sutil piston, a handle seeured to the cylinder, a valve-box within sueh liaiulle, a disk ser ured betul'een the eylinder end and the vulve-box. a hollow distribution-valve el unequal diameters slidable within the valve-box, exhaust-passages in such valve and au annular recess, uneipral areas on the valve to l'oriu two differential pressure areas, an exhaustpassage communirating with the hollow distributien-valve and to atmosphere, inleiporl's in the handle lor two eonlinno-osl streams ol" air under high airl low pressure, throttle-valves governing suoli inlets aud Vmea 'lier operating tue tlufottle-valvos, ports to con: uol'I :,onstaruily air under liigi pressure to the smaller areay et the distribution-valve to aetuate the valve in. one dire#- l'iiin, ports governed by the dis'itribulwuvalve to conduct air under liigh pressure behind the piston for the blow stroke, ports l 'dfi under high pressure at the end of the blow stroke around the annular recess in the rear of the piston to the larger area of the distribution-valve to actuate the valve in the contrary direction, ports governed by the distribution-valve to conduct air under low pressure in front ofthe piston for the return stroke, ports governed by the distributionvalve to exhaust air behind the piston to atmosphere, and ports governed by the piston to exhaust air under pressure acting on the larger area of the distribution-valve, at the end of the return stroke substantially as described.

6. A power-hammer consisting of a cylinder, means for carrying a tool in the mouth of the cylinder, a piston slidable in the cylinder, a recess formed in the rear end of such piston, a handle secured to the cylinder, a valve-box within such handle, a disk secured between the cylinder end and the valve-box, a hollow distribution-valve of unequal diameters slidable within the valve-box, exhaust-passages in such valve, and an annular recess, unequal areas on the valve to form two differential pressure areas, an exhaust-passage communicating with the hollow distribution-valve and to atmosphere, inlet-ports in the handle for two continuous streams of air under high and low pressure, throttle-valves, governing such inlets and means for operating the throttle-valves, ports to conduct constantly air under high pressure to the smaller area of the distribution-valve to actuate the valve in one direction, an expansion-valve slidable in the valvebox, equal pressure areas at each end of such expansion-valve, ports to conduct constantly air under low pressure to the rear oi such expansion-valve, ports governed by the distribution-valve to conduct air under high pressure behind the piston for the blow stroke, ports governed by the piston to conduct air under high pressure admitted behind the piston to the front pressure area of the expansion-valve to move the valve backward and cut off the admission of air under high pressure behind the piston when the piston has made but a portion of the blow stroke, ports governed by the distributionvalve to exhaust air under pressure in front of the piston to atmosphere, ports governed by piston to admit air under high pressure around the recess in the rear of the piston to the larger area of the distribution-valve to HARRY BENWELL STOCKS.- JOHN RACKER WEBB, JUNIOR.

Witnesses:

NORMAN KIERNAN, HUBERT BUx'roN JAMESON.

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