US1636651A - Valve for pneumatic tools - Google Patents

Description

. 1,636,651 July 19 1927' l w. A. SMITH, JR,

VALVE FOR PNEUMATIC TOOLS Filed Nov. 5. 1926 Patented July 19, 1927.

, UNITED STATES APA 1,636,661 TENT OFFICE.

WILLIAM A. sMITII, JR., OE NEW YORK, N. Y., AssIeNoRv TO INGERsoLL-RAND ooM- EANY, OE JERSEY CITY, NEW JERsEY, A CORPORATION OE NEW JERSEY. Y

`VALVE EORINEUMAT'IC TOOLS.

Application filed November This/invention relates to pneumatic tools, but more particularly to an improved distributing valve for tools of this type.

The objects of the invention are to obtain a quick and positive action of the valve and to obtain a powerful blow of the hammer piston against the working implement.

Other objects will'appear hereinafter and to all of these ends the invention consists of the combination of elements, features of con struction and arrangementof parts having the general mode of loperation substantially as hereinafter described and claimed and illustrated in the accompanying drawings, in r which Figure l is a sectional elevation of a pneumatic tool showing' the reciprocatory elements in one or' their limiting positions, and

Figure 2 is a view similar to Figure l showing the valve and the piston in another position.

Referring to the drawings, the tool comprises a cylinder A having a bore B in which is arranged a reciprocatory hammer Apiston r C provided in this instance with a neck C near its forward end. A free exhaust port D is formed in the cylinder A for exhausting pressure fluid from the front end of the cylinder and is controlled only by the pis- 30 ton C.

A closure for the front end of the cylinder A is provided in the form of a front cylinder washer E which projects partly into the cylinder and has a bore F to receive slidaloly an anvil block G adapted to transmit the blows of the hammer piston C to a drill steel 'H supported by a. front headL J. A plate K interposed between the front cylinder washer E and the front head J acts as a closure tor the front end of the bore F and is bored to receive slidably the front end of the anvil block G. The forward portion of the bore F is in this instanceV enlarged somewhat to accommodate a head L carried by the. anvil block G intermediate its ends.

The rearward end of the cylinder bore B is closed by a plate O which also serves as a seat for a valve chest P in this instance arranged at the rearward end of the cylinder. 50 Tn accordance with the present invention the valve chest P is provided with a longitudinal chamber Q, having an enlarged portion R' at its forward end.

l/ithin the chamber Q is arranged a dilerential type distributing valve S having 5, 1926. serial No. 146,394. f

an enlarged head rT which extends into the enlarged .portion ROI' the chamber Q and has front and rearward actuating surfaces T `and T2 respectively. In the rearward portion ofthevalve S is a recess U which is in constant communication with the atmosphere tl'irough an exhaust passage V in the Yvalve chest P. l Y

A plurality of` ports YVV are formed through the valve S, preferably near the rearward endthereof, and are adapted to registerwvith a supply passage X leading through the valve chest, the plate O and the wall oi the cylinder A-to the front end of the cylinder bore B. Radial ports Y leading from the .forward end of the recess U through theenlarged head T are adapted to register with a supply passa-ge Z leading from the valve chamber to the rearward end of the cylinder bore B for exhausting pressure fluid 'trom tl'ierearward end ot the cylinder A@ I Y Y f f Suitable'means are provided to utilize a portion of the pressure fluid admitted to the rearward end of thev cylinder bore B for throwing the valve rearwardly. To this end a passage'b formed in the cylinder A leads from a point rearwardly of the free exhaust port D to communicatevwith its rearward end with the enlargedportionR of the chamber Q.. Within the enlarged 'head T is formed an expansion chamber o andvp'orts fl leading from the expansion chamber c are adapted to communicate with the passage o when the valve is in its forward position to admit pressure fluid into the said expansion chamber c. The exhaust .of pressure fluid from the expansionchamber c -is effected through a .passage e leading from the front end of the :chamber Q to a point in the cylinder Abore B preferably in the same transverse plane asythe exhaust Vport D.

The admission of pressure fluid to the drill is effected through an inlet passage f in the valve chest P, leading to a. port g in the valve chamber between the supply passages X and Z.v The means for conveying pressure fluid from a suitable source of supply to the inlet passage f have been omit-ted from .the drawings, but it is to be understood that IUO such means may Yconsist of the usual hose 0r pipes commonly used for this purpose.

A .small passage 7L in the valve chest P registers at one end with the ports el in the head T to establish communication between chamber c and the passage f for admitting pressure fluid .to the expansion chamber c for holding the valve after said valve has been thrown rearwardly.

In order to prevent the tool from jumping away from the work upon the admission of pressure fluid to the front end of the cylinder, a passage y' communicating at its rearward end with the` supply passage X is formed through the front end of the cylinder and through the front cylinder washer E to communicate with its forward end with the enlarged portion of the bore I?, forwardly of the head Ii of the anvil block. In this way, upon the admission of pressure fluid to the front end of the cylinder, a portion of such pressure fluid will pass into the bore F and acting against the head L of the anvil block will hold said anvil block firmly against its seat until the free exhaust port D has been uncovered by the piston C, whereupon the pressure fiuid from the bore F will be exhausted to the atmosphere together with the pressure fluid 'in the front end of the cylinder,

In the operation of the device, with the valve in the position illustrated in Figure. l, pressure fluid entering the inlet passage 'f will pass through the port g and thence through the supply. passage Z into the rearward .end of ythe cylinder' bore B to drive the piston C forwardly to deliver its blow. on the anvil block G. After the piston C uncovers the passage b, pressure fluid will flow from the rearward end of the bore B through said `passage b and through the ports Z in the valve head T and throw the valve rearwardly. y

IVith the valve in this position, the ports Z will be moved into registry with the small passage 7L so that pressure fluid will flow directly from the inlet passage into the expansion chamber c for holding the valve S in thrown position. Such pressure fiuid admitted into the expansion chamber' c will then remain therein to hold the valve rearwardly7 until the piston C has returned rearwardly a suiiicient distance to enable the neck C to establish communication between the exhaust passage e and the exhaust port d, whereupon the pressure fluid in the expansion chamber c will be exhausted to atmosphere through the channels described. After the pressure the expansion fluidin the expansion chamber c has been thus exhausted, the live pressure fluid acting against the rearward actuating face T2 will throw the valve S forwardly to again ladmit pressure fluid through the supply passage Z `into the rearward end of the cylinderbore B.

With the valve in its rearward position, the radial ports Yin the head T will register with the supply passage Z and the pressure fluid in the rearward end of the bore B will then be exhausted through these channels and ,through the recess Il in the valve and the passage V to the atmosphere. Similarly, after the valve has been thrown forwardly, the ports IV in the valvewill be in registry with the front supply passage X to permit the exhaust of any pressure fiuid or air compressed by the piston from the front end of the cylinder bore B through the valve and through the passage V to the atmosphere. y

I claim: i

A pneumatic tool comprising a cylinder having a free exhaust port for the front end thereof, a piston in the cylinder controlling the free exhaust port, said piston having a neck, a valve` chest having a valverchamber, supply passages leading from the valve chamber to the ends of the cylinder, a valveV chamber having a recess in constant communication with the atmo-sphere, a head on one end of the valve having opposed actuating surfaces and an expansion chamber, said head also having radial ports, the rearward actuating surface being constantly exposed to pressure fluid for throwing the valve forwardly, ports in the valve to register with the supply passages for exhausting pressure fluid from the ends of the cylinder into the recess, a kicker passage leading from the cylinder and adapted to register with t-hel ports in the head for admitting pressure fluid to the expansion chamber to throw the valverearwardly, and an exhaust passage leading from the front end of the valve chamber. to a point in the cylinder in the same transverse plane as the free exhaust port, communication between the exhaust passage and the free .exhaust port being controlled by the neck of the piston.

In testimony whereof I have signed this specification.

WILLIAM A. SMITH, JR.'

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