US727431A - Pneumatic tool. - Google Patents

Description

No. 727,431. PATENTE) MAY 5`, 1903.

' 0. W. PECK.

PNBUMATIG Tomi'. PPLIUATION FILIJDJULY 17, 19702.

2 SHEETS-SEEET l.

No MODEL.

A :nn/Hmml WITNESSES ATTORN EY No. 727,431, PATENTE) MAY 5, 1903.v o. W. BECK. PNEUMATIG Tool-. APPLIATIDH FILED JULY 17, 1902.

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ATTGRNEY Yiliarrnn STATES Patented May 5, 1903.

ATENT OFFICE.

CLARENCEIV. PECK, OF ATHENS, PENNSYLVANIA, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO IMPERIAL PNEUMATIO TOOL COMPANY,

OF ATHENS, PENNSYLVANIA.

PN EUNIATIG TOOL.

SPECIFICATION forming part of Letters Patent No. 727,431, dated May 5, 1903.

I Application filed July 17, 1902- Serial No. 115.958. (No model.)

To @ZZ whom, it inlay concern:

Be it known that I, CLARENCE W. PnoK, a citizen of the United States, residing at Athens, in the county of Bradford andState of Pennsylvania, have in vented certain new and useful Improvements in Pneumatic Tools, of which the following is a specification.

My invention relates to improvements in pneumatic hand-tools wherein a reciprocating 1o piston actuated by compressed air or other iiuid under pressure is made to drive various tools such as are used in chipping, calking, drilling, and other operations.

The main feature of my invention relates to the valve mechanism by which the movements of the piston are controlled and wherein the valve is arranged concentric with the piston-cylinder in order thattheremay be a maximumpiston travel, together with a minizo mum length of tool; andthe object of this portion of my invention is to providea valve which shall be positive and steady in its operation and which will impart a quick change of stroke to the piston, thereby` increasing 2 5 the number of blows per minute of the piston upon the head yof the working implement, and, furthermore, to so construct the valvechamber as to provide a cushion for the piston upon reaching the end of its rearward 3o Stroke.

Another feature of my invention relates to improvements in the controllingvalve, by which the admission of the air to the tool is controlled and adjusted, the object of this portion of my invention being to provide a liner and more sensitive adjustment than is present in the tools now known to me.

Other features of my invention relate to the construction and arrangement of the 4o valve, valve-box, ports, and passages, whereby I attain improved results, which novel features of constructionwill appear hereinafter and be more particularly pointed out in my claims.

I attain the objects of my improvements by the construction and arrangement of parts, as illustrated in the accompanying drawings, wherein I have shown my invention as applied to apneumatie hammer, and in which- Figure l represents a longitudinal section of mycomplete tool; Fig. 2, a plan view of the same, the rear portion being shown as sectioned at right angles to. Fig. l; Fig. 3, a section on an angle intermediate between the sections shown in Figs. l and 2; Fig. 4:,a rear 55 View of the cylinder with the other parts removed; Figs. 5, 6, and 7, sectional details of the valve-box and valve, and Figs. 8 and 9 details of the throttle-valve.

Like letters refer to like parts throughout 6o the several views.

A represents the cylinder or barrel of the tool, provided at one end with a socket to receive the shank of a chisel or other implement, and at the other end havinga flange B, with a rearwardly-projecting rim C, against which is set the forward face of the valve-box D, said valve-box being centered by fitting within the rim C. This valve-box is carried within a chamber E, to which is attached the 7o operating-handle F. The exterior wall of chamber E is screw-threaded to receive the sleeve G and jam-nut H, by which the several parts are assembled and rigidly secured together. W'ithin the valve-box D, which is 75 provided with passages, ports, and grooves, as hereinafter described, is a cylindrical valve I, adapted to travel longitudinally therein, the inner diameter of which corresponds with the bore of thecylinderA and forms a prolon- 8o gation thereof. This valve is provided with ports and exterior grooves, which as the valve reciprocates are brought into alinement with the grooves and ports in thevalve-box to permit the admission and exhaust to and from the ends of the piston P by way of corresponding passages and ports in the cylinderA, as will hereinafter appear. At the rear of the valvebox and held between it and the head of chamber E is a anged bushing J, which projects 9o into the valve I, thereby forming a chamberj, in which the rear anged portion of the valve I reciprocates and io and fromy which chamber ports and passages are led to the cylinder through the valve-box, whereby air is alternately admitted to and exhausted from the opposite sides of this anged portion of the valve as the piston P travels back and forth in the cylinder to shift the valve at the proper periods. roo

The supply-hose is coupled to the handle at K, the air-supply to the tool being controlled by the throttle-valve L, the flanged head of which seats against the ring M, which is held in place by the bushing K, the valve being pressed to its seat by the spring N. 'lhe valve is opened by pressing upon the thumb-lever O, which acts upon the valvestem, as indicated. Referring to Figs. 8 and 9, it will be seen that the Valve L has three diameters, the smallest diameter forming the stem, the nextlarger diameter ttingthe bore of the ring M, and the largest diameter forming a head l, which seats against the ring M. The force of the air-pressure against said head, in addition to the spring N, holds said valve in closed position at all times when not actuated by the thumb-lever O. The shoulder between the stem portion and the next larger diameter of the valve L is provided with a series of bevels Z', cut at diiferent angles, whereby when the valve is pressed outwardly first one bevel will open communication from the air-supply to the admissionduct c, and then the next less acute bevel, and so on, until the valve is thrown completely open. By this construction of the valve the air is admitted gradually to the tool, and after a little practice the operator can so adjust the thumb-lever O as to admit the air in varying quantities, according to the speed of the piston travel and force of blow desired. In addition to this graduated throttle-valve I provide a regulating-valve Q at the head of duct a, which valve is bored to correspond with said duct and is provided with a port b, adapted to register with the admission-passage c in valve-box D. This Valve is threaded into the handle and is provided with a serrated head S, the beveled teeth on which are engaged by a correspond'- ing beveled locking-bolt R, back of which is a coiled spring, whereby said bolt is held in engagement with said head. By turning the head S in one or the other direction port b will close the opening from duct a into passage c more or less, as desired, and the valve will be held in this adjustment by the lockbolt R.

Having thus described the principal parts of my device, the operation thereof Will now be explained in connection with the relative arrangement of the passages, ports, and grooves in valve, valvebox, and cylinder heretofore referred to. In the several iigures the piston P is shown in its outward position and the valve is shown as set for the return stroke. To accomplish this stroke of the piston, the air passes from the passage c through port d and by way of grooves d' and 'n' through port n into the' passage h, andv thence by way of port h to the front of the piston, thereby driving the piston to the rear. During this stroke of the piston the air is exhausted from the cylinder behind the piston by way of the ports t in the valve I, groove o, port tu, and passages v and .fr in the valvebox and handle. (See Fig. 3.) As the piston approaches the end of this rearward stroke the exhaust from ports t" will be cut off and the entrapped air will be compressed, and as the reduced portion p of the piston enters the bushing J, which it ts snugly, an effectual air-cushion is produced, which will bring the piston to a stop without shock upon the hand of the operator. Before the piston has quite reached the end of this stroke the groove p therein will place passages c and g in communication with passages r q (see Figs. l and 2) by way of ports g fr, thereby admitting live air through port q to the front face of the flange on valve I. At the same time the end of the piston has passed ports s and u', (see Figs. 2 and 3,) thereby opening communication between the rear of the valve and the exhaust-outlet a; by way of the port j and passages t', t, s, u, and c, and the valve will be shifted to its rearward position. In this position of the valve the ports t' therein are brought into register with the groove e', which communicates with the admissionpassage c through the port e, and the air will be admitted to the rear of the piston to force it forward. During this forward stroke of the piston the exhaust will take place through port h', passages h 7c, port fm, grooves m', o', and o, which are then in register, port w, and passages u and (See Figs. l and 3.) Just before the piston arrives at the end of its forward stroke the ports (see Fig. 2) will be uncovered and live air will pass from the cylinder through passages s t t to the port j in chambery, and the exhaust from in front of the valve in this chamber will be opened through port q', passages q and r, port r, groove p, port u, and passages u, U, and (see Figs. A2 and 3,) upon which the Valve will be shifted to its forward position, as shown in Figs. l, 2, and 3 of the drawings, and the cycle of operations will be repeated.

It will be noted that there are no differential areas on the valve to be acted upon by the duid-pressure in shifting the valve, but that admission and exhaust takes place simultaneously, first on one side and then on the other side of the valve-flange in chamber j, by reason of which I attain a positive and quick-acting Valve, the pressure upon one side of the shifting ange being relieved the moment live air is applied to the other side. While apparently there is a differential area between the front and rear faces of the iange on the valve in chamberj, as a matter of fact this difference of area does not exist, so far as the operation of the valve is concerned, because when the valve is in its rearward position the forward rim of the valve is subjected to live-air pressure within the cylinder, and when the live air is admitted to the rear of chamber j the areas at each end of the valve corresponding tothe thickness of the shell of the valve will be in balance, so that the effective pressure area on the rear portion of the valve in chamber j will correl'OO IIO

spend precisely to that on the forward side of the flange.

In order to prevent the valve from fluttering as it is shifted from one position to the other, I provide a small port f, leading from admission-passage o to chamber j, the diam-` eter and position of this port being such that in either position of the valve a small opening will be provided from said passage into the chamber j, whereby live air will be admitted, so as to force the valve to its seat and hold it there in either position, and this feature I consider as an important item `in my invention.

By reason of the large admission-ports t'` construction of my tool to the precise arrangement of the various passages, ports,l

and grooves nor to exact details of construction.

Having thus described my improvements, what I claim as my invention, and desire to secure by Letters Pat-ent, is-

l. In an impact-tool, the combination of a cylinder, a reciprocating piston therein, a cylindrical ported valve movable in line with the piston in a chamber at one end of the cylinder, and `an enlargement on the valve traveling in a separate chamber, to and from each side of which motive iinid is admitted and exhausted at each stroke of the piston to shift the valve.

2. In an impact-tool, the combination of a cylinder, a reciprocating piston therein, a cylindrical ported valve movable in line with the piston in a chamber at one end of the cylinder, a ring or iiange on the valve traveling in a separate annular chamber, to and from each side of which motive iuid is admitted and exhausted at each stroke of the piston to shift the valve.

3. In an impact-tool, ythe combinationof a cylinder, a reciprocating piston therein, a cylindrical ported valve movable in line with the piston in a chamber at one end of the cylinder, a bushing projecting into the valve from the head of said chamber, and an. enlargement on the-valve traveling in a separate chamber formed thereby, to and from each side of which motive fluid is admitted and exhausted at each stroke of the piston to shift the valve.

d. In an impact-tool, the combination of a cylinder, a reciprocating piston therein, a cylindrical ported valve movable in lino with the piston in a chamber at one end of the cylinder, a hollow bushing projecting into the valve from the head of said chamber, an enlargement on the valve traveling in a separate chamber thus formed, to and from each side of which motive iinid is admitted and exhausted at each stroke of the piston yto shift the valve, and a reduced end on' the piston which enters'said bushing on the back stroke to cushion the piston.

5. In an impact-toohthe combination of a cylinder, a reciprocating piston therein, a cylindrical ported valve movable in line with the piston in a chamber at one end of the cylinder, an enlargement on the valve traveling'A in a separate chamber, to and from each side of which motive iiuid is admitted and exhausted at each stroke of the piston to shift the valve, anda port opening into said lastnamed chamber whereby live :duid is admitted behind said enlargement ateither stroke of the valve toi-hold it to its seat.

6. In an impact-tooL-the combination of a n cylinder, a reciprocating piston therein, fa

valve to control admissionand exhaust to and' from the piston, meanscontrolled by the pis- I ton for shifting the vvalve by the motive duid, a a'ngdor' enlargement on the valve traveling in a separate chamber, and a port atqa' medial point in the Wall of said chamber in constant communication with the fluid-supply, Whereby live duid is directed to one side,

or the other of said ange at each stroke of the valve to hold' it to its seat.

7. InI an impact-tool, the combination of a cylinder, a reciprocating piston therein, a cylindrical valve movable in line with the piston in a chaz'nbei` atene end of the cylinder,

a plurality of grooves in the walls of said chamber, admission and exhaust passages and ports leading to and from said grooves, grooves on the valve acting in conjunction with the.

chamber-grooves whereby the far end of the cylinder is opened alternately to the admission and exhaust, ports through thevalve whereby the nea-r end of the cylinder is opened to admission and exhaust, the admissionports in the valve being of larger'area than the exhaust-ports, and the admission-ports and grooves in the valve-chamber for the near end of the cylinder being of larger area than;4

i those for the far end for the purpose set forth,

and means controlled by the pistonforj'shifting the valve by the motive Huid.

8. In an impact-tool, the combination of a cylinder, a reciprocating piston therein, a cylindrical valve movable in line with the piston in a chamber at one end of the cylinder, a plurality of grooves in the walls of said chamber,admission and exhaust passages and portsleading to and from said grooves, grooves and ports in the valve whereby the far and near ends of the cylinder are opened alter-l nately to the admission and exhaust, an enlargement on the valve traveling in a separateehamber, ports and passages leading from each end of said ehamberfto the cylinder intermediate its ends, and grooves on the passages leading to the admission and exhaust.

9. In an impact-tool, the combination'of a cylinder, a reciprocating piston therein, a cylindrical valve-box centered on the end of said cylinder, admission and exhaust passages through the valve-box registering with corresponding passages in the cylinder walls, grooves on the inner periphery of the valvebox with ports leading to said passages, a grooved and ported .valve movable in said valve-box in line with the piston and forming a prolongation of the cylinder, a flanged bushing held between the end of the valvebox and the'head of an inelosing chamber, i

'chamber in which travels an enlargement on the valve, and ports and passages leading to and from said chamber, under control of the piston, to the admission and exhaust.

In testimony whereof I have affixed my signature in presence of two witnesses.

CLARENCE W. PECK.

Witnesses:

' Units@ BROWN,

GEMUNN.

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