US1319034A - Oliver - Google Patents

Description

0:0. APP.- PNEUMAHC IMPLEMENT.

APPLICATION FILED 'JAN- I9. 1915.

1,319,034. Patented oct. 21,1919.-

UNITED sTATEs PATENT oEEicE,

OLIVER 0. APP, 0F NEW YORK, N. Y. i

PNEUMATIC IMPLEMENT.

To all whom t 'ma concern.' 4

Be it known t at I, OLIVER O. APP, a citizen of the United States, residing at the city of New York, in the borough of Man- -hattan and State 0f- New `York,'have invented certain new and useful Improvements in Pneumatic Implements-.of which the foll implements which are brought into contactv with the rock, as a rock drill, or pneumatic hammer and' in fact any fluid pressure devices ofthis character. t

The primary object of this invention is to provide an implement Ywhich automatically starts operating when the tool carried thereby is brought into contact with and pressed against the Work and will immediately stop operating before another blow can be delivered when the pressure is removed from the tool. With' tunneling machines where the invention has its chief adaptation, this is of importance since the several implements carried by the rotating head operate under varying conditionsand frequently one or more of the tools are not in contact with the rock.

while the others are operating. Under these 'circumstances the implements 'whose tools are not in contactwith the rock should immediately cease operating otherwise the next blow of the hammer or piston of the instrument will drive the tool from its holder and also break or otherwise injure the parts of the implement. Another object of the invention is to provide an implement of this character of a' Specification of Letters Patent.

section of ,an implement. constructed in accordance with the principles of my invention;

Figs'. 2,3, 4 and 6, respectively, are sections taken on the lines ,2 2, 3-3, 1 /1,A

6 6, respectively; and

Fig. 5 is an end View of the implement looking toward the left. l The implement casing or cylinder 1 is 'open at both ends and is' preferably constructedof steel as are practically all of the Patented Oct. 21, 1919. Application led January 19, 1915.4 Serial No. 3,016.

other parts of the implement, so as to minimize the danger of the breakage, due to the vibrations and strains to which they are nec-v essarily subjected. The vopen rear end' of this casing is closed by a head 2 which fits intothe bore of the casing',`these parts being accurately machined so that they' form an air-tight joint. The head2 is provided with a flange 3, fitting against the rear annular end face of the casing againstl which it is maintained by a heavy set-screw 4, which is threaded into an aperture in `a boss carried by a hollow casing 5. This casing or cap which has suitable exhaust openings 5 therein is threaded interiorly and is screwed down over the'exterior surface ofthe rear end of the casing l, the construction described maintaining the headfirmly in place against the heavy pressureto which it is subjected. The interior surface ofthe head is ,provided with a cylindrical recess 7, the outer walls of the recess diverging slightly as at 8,- forming a chamber into which the end of the piston enters at the completion of its rearward stroke, the purpose of which will be hereinafterset forth.

Fitted into the forward end of the casing 1, is a differential piston or hammer which is constructed from a solid lbar of steel and has noopenings inthe same, this piston constituting the striking member which delivers the blow `against the tool and in one practical embodiment of the invention is about 3% inches in diameter at its larger end, and vweighs about 25 pounds, so that 'it constitutes a solid massive piece which is not liable to shatter, spread or in othervways be injured by the repeated blows which it strikes. vThis piston is cylindrical in vform and consists of the two heads 10' and 11; the head 10 which faces the rear end of the casing is of somewhat larger diameter than the other `head r12 to which it is joined by a neck i piece 12 so that a shoulder 13 is provided `against which the fluid Vpressure may act constituting a differential piston.

The casing is bored to suitable diameters as at 14 and 15 so that the'heads 1() and 11 may have a sliding lit therein, and three or four thousandths of an inch clearance is preferably allowed so that there will be no tendency for the pistonl to stick should it expand slightly, due to the heat generatedby the friction between the walls of the casing and the piston, or due to the concussion of the blows which the piston strikes against the tool holder. However, to avoid any leakage of the fluid, the heads are providedA with piston rings 16.

Mounted in the front endof the casing or cylinder 1 is a nose-piece or bushing 17, which is driven into the casing with a force fit and is thereby prevented from turning, the internal diameter of the casing being slightly larger than the bore 15 to provide a shoulder 18 against which the rear end of the bushing is vadapted to seat. Slidably mounted in this bushing is a. tool holder 19 which is preferably cylindrical in form throughout the greater portion of its length but is squared at its rear end as at 2Q, the squared end passing through a suitable squaied,aperture in the rear end of the bushing ornose piece 17. This tool holder is mounted so as to freely slide within the bushing and is prevented from' inadvertent displacement therefrom by a pin 21, which fits into a suitable groove 22 cut in the. bushing 17 and passes throughopeningsl in the casing; the tool holder having an elongatedy groove 2e in its lower face just abovethe pin, the walls of which co-operate with this pin to limit the free movement ofthe tool holder. The ends of the pin 21 extend the outer periphery of the casing andare flush with the same'and a resilient spring band 23 surrounds the casing and covers the ends of the pins to prevent their inadvertent dis.

placement. The tool holder 19 is also preferably of steel and constitutes asolid massive piece, the weight of which is approximately fifteen pounds,'wherev a plunger o r piston 'of twenty-five pounds of weight is used, the tool holder being lighterthan the plunger so that'when the latter is driven against the same, there will not be the tendency foi.` the plunger to rebound, butrather for `the heavier mass to drive the tool holder forward and fol-low it through a greater distance whereby the strength of the blow delivered is increased. The front end of the tool holder is provided with la centrally disposed squared recess whichas adapted to receive a tool 25, thesliank of the tool being squared to t within this squared aperture. The' tool is preferably shoittin length so as it will not be broken or shattered by the violent impact with which it strikes against the rock or other namely, the tool, tool holder and piston, are alone subjected to the severe strains and stresses occasioned bythe driving of the piston forwardly against the tool holder with such severe blows as to cause the shattering of the rock and since they are all of steel and in each instance constitute'a single solidmassive piece, which` are not liable to be broken, but will readily withstand any tendency to shatter or spread.

The tool holder extends beyond the front end' ofthe casing and is provided with an annular flange 26 whichy is provided with an annular groove 27 therein which is adapted to receive one portion of a spring/ resilient retaining clamp 28 which also engages notches 29 in the square-corners of the tool for retaining `the latter against inadvertent displacement from thetool holder due to the vibration of the implement when in operation.

Between the walls 14 and' 15 of the casing yand neck 12 of the piston which is of slightly smaller'diameter than the Ahead 11, there is formed an annular chamber or space a which is bounded at its ends by the shoulder 13 which connects the neck with the large head 10 of the piston and at the other end by a shoulder 12 which connects the neck with the small head 11 of the piston.

Referring now to the manner in which the implement is pneumatically actuated, as before stated, the differential piston hammer is provided with a shoulder 13, which, together with a shoulder12, formed by the junction of the neck l12 of the piston with its head 11, and the walls of the cylinder, forms a chamber a to which 'Huid pressure is admitted through ports'` 30 and 31, leading through the top partof the casing. The port 31, as shown, is preferably inclined and converges towardthe porta 30 and the cylinder. Adjacent the inner ends of these ports, the bore of the cylinder has a groove or annular section of slightly lenlarged diameter, as at b, so that when the piston is in its extreme forward movement-and the shoulder 13 rests against the shoulder l5 which connects the bores 14 and 15 of the cylinder, Huid pressure will still be freelyadmittedto exert its pressure against the shoulder 13.

The admission' of the fluid pressure through theI ports 30 and 31 is controlled by the valve mechanism which will now be described.

The `curved peripheral surface of the casing above the ports 30 and 31 is -cut away as at 32, to provide a fiat seat upon which the valve chest 33 is mounted and secured in place by the bolts 34 to provide a substantially air tight connection between the chest and casing. The main reservoir chamber of the slide valve. The fiuid pressure. is admit-- ted to the chamber c of the valve chest Y through the pipe 38, which is threaded into a sleeve or boss 39carried by the valve chest, it being understood that the pipe 38 conducts the fluid pressure to the implement from any. suitable source. Leading rearwardly from the chamber c is a conduit 40 which is enlarged at its rear end as at 41 and extends downwardly so that the rear end of the slide valve is exposed to the action of the fiuid pressure. The opposite or front end of the valve is open to the atmosphere, the passage 42 being provided through the front face of the valve chest into which one end of a loosely fitting rod 43 is adapted to extend, so that it presses against the end of the slide valve. The' rod 43 extends forwardly to the extreme forward end of the casing and lies in a groove 44' in the casing. The front end of this rod abuts against a lug 45, whichY forms an integral part of the tool-holder. As .the rod 43 fits loosely into the opening 41 in the front end of the valve chest, the same is open to the atmosphere, and in order to prevent the leakage of the fluid pressure between the contacting faces of the valve and valve chest along the line 46, a fiap Valve of leather or other construction is fitted into the slide valve. This flap valve may comprise a flap of leather 47, which is inserted into a suitable transverse groove-in the top surface of the valve. It has been -found impossible, however, in the construction of the implement shown, to make the joint entirely airtight, and this fact has been taken advantage of in lubricating the tool holder, which is accomplished by providing the duct o48. As is common in fluid pressure tools or implements of this character, the lubricating oil is fed in mixed with the compressed air, so that when the same escapes between the surfaces designated 46, the oil will follow the i groove in the casing until it reaches the duct, which will carry it downwardly, tothe face of the tool-holder so that the same will slide without undue friction in the bushing 17. v

The fluid pressure is admittedto the rear end of the piston by means of the longitudinally disposed inlet conduits`l50, which, asis clear from Fig. 2 of the draw1ng,are drilled in the side walls of the casing, and are ten in number, five being arranged each side, al-

-vide theconduits 63 w o en to the atmosphere at their rear endsf. T ese conduitsare four in number, and are 1 though a greater or less number of conduits may be provided, the essential point being that sufHcient conduit areabe provided so that the fiuid pressure may pass freely to the rear end of the piston at the proper timein the operation of the-same. These conduits 50 lead into the bore 14 of the casing through openings 51 at their front ends and at their rear ends by the openings 52, the casing being of enlarged diameter adjacent the openings 52 to provide a ybeveled surface 53 so that when the head of the piston reaches the ports 52,v the fluid pressure willnot be cut off but will permit the fluid pressure to enter the compression cup chamber 7.

The exhaust ports for the casing are, in the preferred embodiment of my invention, formed by providing longitudinal grooves in the. exterior surface of the casing, which grooves are surrounded by a metallic shell 54 which is fitted over the casing to form the exhaust conduits( The casing is preferably of reduced diameter so that the-exterior surface of the shell and the front end of the casing will be flush; the front end of this shell fitting against a shoulder 55, while the rear end fits into a suitable groove 56 formed in the c ap 5, which rigidly maintains the same in place. These exhaust conduits are in several sets, one set 57 being four in number and arranged in the lower portion of the casing, which conduits lead into the cylinder at a' point 58 adjacent the end of the tool-holder and also through openings 59 which are arranged to the rear of the piston when the'same is in its forward position. The conduits 57 extend to Ithe extreme rear of the casing and also through openings 60 formed inthe flange of the cap 3, so that the air may be freely exhausted through the exhaust'opening 5 in the cap 5. Another set of exhaust conduits 61 four in number, lare arranged on the top' of the casing at the rear end thereof, which conduits havevopenings 62 leading into the cylinder at -a point in radial alinement with the openings 59, and lsimilar to the other exhaust conduits described, pass through vsuitable openings in the fiange of the cap 3', so that they may be exhausted through the openings 5. For the rear end of the cylinder 8 exhaust conduits are therefore provided, but for the forward end of thecylinder, since the'valve mechanism prevents the conduit from being extended forwardly, and since the inlet conduits 50v prevent other conduits from beingformed in the side of the casing and extended to the rear end of the casinglit is necessary to proshownin cross section in Fig.' 4', and openv into the cylinder as 'at 64 extending lrearwardly yof the cylinder to a point approxiichpreferably do not mately opposite the ports 30 and 31; these conduits will Ibe hereinafter -referred to in the description of lthe operation of the implement.

Assuming that the line pressure is being conducted to the implement through the pipe connection 38, and that the tool is removed from work, the fluid -pressure behind the slide valve will immediately throw it ,i to closed position andthe tool will remain inactive. 1f, however, the tool 25 is forced against the work through `the instrumentality of the rod 43 the valve 35 will be pressed or moved toward its openy position corresponding to the pressure which is exerted by the tool upon the work. The registering of the ports in the slide valve with the ports 30 and 31 will admit fluid pressure to the chamber a, and since the rear of the piston is open to atmosphere through the exhaust conduits 57 and 61, the fluid pressure exerted against the shoulder 13 will tend to force the 'piston rearwardly in the cylinder at a considerable speed. As the 'piston moves to its rearmost position the shoulder 13 passes beyond the openings 51 of the inlet conduits 50 so that the lfluid pressure is admitted behind the piston and as the momentum of this piston carries it rearward, a. part of the fluid pressure will be trapped withinthe compression cup 7 and compressed to an extent greater than line pressure. As for Y example, the speed of the piston may be such that its momentum will be'suficientto permit it to compress the fluid pressure within the trap chamber 7 to of its volume, there will be a corresponding increase of pressure, and if a line pressure of 80 lbs. were used, this would be 640 lbs., which would be acting against each square inch of the rear face of the hammer or' piston to again move it forward.

The forward movement of the piston is, therefore initially received by Lthe comf pressed air within the chamber 7, and after the end of the piston has passed out of this chamber the fluid pressure will be admitted to the cylinder behind the piston until the shoulder 13 again covers the openings 51 of the inlet conduits 50, after which the piston will move forward under the expansive action of the' fluid preure until the exhaust ports 59 and 62 are opened when the piston will continue its forward movement under its own momentum until it strikes the squared end 20 of the tool-holder, which blow will be communicated to the tool 25 which is incontact with the work and cause the tool to impinge against the rock or other hard surface to be out to shatter the same. lurinfr this forward movement of the piston, as in a l movements of the piston, the chamber to the front of the head 11 is open to atmosphere through the. exhaust conduits 58, but in order to prevent any unnecessary retardation of the piston on its forward stroke the additional exhaust conduits 63 are provided, which, as described, do not lead to the atmosphere, but merely serve as an auxiliary space in which part of the air to the front of the head 11 which lcan escape through the conduits 57 may be compressed on the forward stroke of the same. This has been found a desirable construction, since the exhaust ports 57 which open to the atmosphere are not of sufficient area to permit the desired rapid reciprocati'on of the piston within the cylinder. If desired, the conduit 63 lcould also lead to the atmosphere, but this construction would weaken the casing and 1 have found this unnecessary when the additional compressing space is supplied.

During this forward movement of the piston the fluid pressure which is admitted to the chamber is forced back into the valve chestl by the forward movement of the shoulder 13, but the comparative areas of the shoulder 13 and the rear face of the piston are such that this slight retardation of the piston in its forwardv movement does not materially affect its speed and the force of the blow delivered.

Just prior to the piston striking the toolholder the'chamber to the rear of the piston is thrown to exhaust by means of the exhaust conduits 57 and 61 as has been referred to, and after the lblow is delivered the piston again moves rearwardly under the pressure exerted upon the shoulder 13. The actuation of the piston while in operation is very rapid and in the actual ,embodiment'of the machine as many as 1000 blows per minute have been struck which, due to the weight of the piston, will cause the tool tol impinge against the rock with such violent force that large pieces of the rock are broken from the mass which it is desired to cut, which operation will be continuous aslong as the slide valve remains open. If, however, the tool is not pressed against the work, the unbalanced slide valve will then immediately move to closed position, and through the instrumentalityv of the rod L13 which bears against a portion of the tool holder, force the same forwardly in the cylinder unt-il the walls of the groove 24 engage the pin 21. This movement of the slide valve is practically instantaneous, since in the practical embodiment of my invention which 1v have constructed, the area of the rear face of the slide valve is at least of a square inch area,

and since the line pressure is from'75 to 95 lbs'., this whole pressure is exerted against the slide valve to throw it forwardly. 1t

is also clear that by providing a plurality of portsin the casing and slide valve to completely close these ports 31, the slide valve does not have to move through an extended distance. rlhis action, as stated, is practically instantaneous and due to the construction of the differential piston and air ports and arrangement of inlet and exhaust ports shown, the piston will be stopped before it is moved to deliver a blow against the tool holder, irrespective of its position at the instant the tool is removed from the work. If, for example, the piston hasjust delivered its blow and is in the position shown in Fig, 1 when the slide valve is closed, the fluid pressure will act expansively against the shoulder 13 and move the piston rearwardly until the exhaust openings 57 and 62 are closed. After closing the exhaust openings the air to the rear of the head 10 will be compressed until the pressure exerted upon the shoulder 13 is equal to the same and the piston willecease moving. Again, assuming that the piston is in its rearmost position and has just started forwardly on its stroke when the valve is closed, here the pressure of the 'compressed air in the trapped chamber 7 will cause the piston to move forwardly at a relatively great speed. This speed will be increased after the piston leaves the chamber as the fluid pressure admitte'd to the chamber through the openings 52 is permitted to act .expansively, but during the forward driving of the piston, since the slide valve is closed, the shoulder 13 will compress the air in the chamber a, which, in the normal operation of the valve. is permitted to l back into the line through the open ports 30 and-31, and the forward movement of the piston will continue until the air within the Chamber a, that is, the air which is trapped by the closing of the slide valve, is compressed until the pressure which it exerts upon the shoulder 13 equals the pressure of the fluid against the rear face of the head J same manner, if the piston is in any of its before another blow can be delivered by the' 10, which, as has been stated, is acting expansively. The piston will, therefore,l be stopped on its forwardmovement before a blow can be delivered lagainst the tool-holder to `drive the saine from the cylinder and perhaps break the pin 21 or mutilate the tool-holder, due to theshock which would be occasioned by the impact of the walls of the groove 24 against the Ipin 21. In the intermediate positions and is moving forwardly or rearwardly, it will b e stopped before the blow can 'be delivered. And I find that even Where the implement is operated so that its piston will deliver from 1000 to 1200 blows a minute, in every instance,

just as soon `as a tool is removed from the work the same immediately stops actuating piston against `(the tool and tool-holder. It is for this reason that the jform of implement shown is especially` adapted f or use with tunneling machines', since in )this adaptation it is impossible to manually control any of the toolswhich are placed upon a rotating head, and the actuation ofthe same must be Y formin due to the simplified form of the valve mechanism, wherein the use of any distributing valves orother auxiliary valves isentirely dispensed with and the control is directly from the main valve.

Another important feature of the invention may be grasped by considering the pressure exerted by thefluid against the unbalanced slide valve, as it is obvious that this ma be controlled within the widest. possib e limits, since if it is desired to 'obtain an implement which will actuate after a certain pressure is exerted upon the point of the tool, it is only necessary to design the slide valve so that, the area which is eX- posed to the fluid p-ressure will correspond thereto; as for example, if in heavy opera tions where the line pressure is 80 lbs. and it is desirable that the tool should only operate when it is pressed with considerable pressure against the work, the slide valve may be so designed'that it exposes an area of l sq. in. to the fluid pressure, in which instance it will take 100 lbs. pressure or I more upon the point of the tool to move the valve to fully open position.

Another advantage of the form of valve mechanism disclosed is that if the tool is only pressed lightly against the lwork the f result will be a correspondinglylight blow, as it is obvious that upon a slight movement of the tool-holder and rod 43 the slide valve will only be partially opened and the amount of fluid pressure Vadmitted to the chamber a will not be sufficient to permit the piston to strike a blow of full strength, as the fluid pressure will act expansively for the greater part of the stroke of the piston.

I claim:

1. In a uid pressure operated implement,

a cylinder, a piston therein having an annular shoulder, said piston and cylinder forming an annular chamber one wall of which is formedby said annular shoulder, a port in said'cylinder leading to said annular chamber, a valve for controlling said port said valve normally biased to its closed position, and means operated by being pressed'against the work for opening said valve.

2. In a fluid pressure operated implement,

a cylinder, a piston therein having an an' nular shoulder, said piston and cylinder an annular chamber onel wall of which is formed by saidannular'shoulder, a port in said cylinder leading to said annular chamber, a valve for controlling said port said valve being normally biased to its closed position, a movable tool carried by said cylinder, and a connection from said movable tool to said valve Whereby When said tool is pressed against the Work said valve is brought to its open position.

3.. ln a pneumatioally operated implement, a cylinder, a diiferential piston therein having an. annular shoulder, said cylinder and piston forming an annular chamber one wall of which is formed by the annular shoulder, a main inlet, port leading to said annular Chamber, a valve controlling said port, and Huid-pressure means for urging saidrvalve toits closed position, and a connection to said valve for opening said Valvewhen pressure is applied to said connection.

4. ln'a pneumatically operated implemend a cylinder, a differential piston therein having an annular shoulder, said cylinder and piston forming an annular chamber, one Waii of which is formed by the annular shoulder, a main inlet port leading to said annular chamber, a valve controlling said port, a

tool movably mounted in said Cylinder, means for urging said valve to its closed position and said tool to its outward position, said means including an intereonneonemesi tion between said tool and valve whereby the movement of one of these parts controls the movement or" the other.

5. ln a pneumatieally operated implement,

Y a cylinder, a differential piston therein having an annular shoulder, said cylinder and piston forming an annular chamber one Wall of which is ornied by the Wall of the shoulder, a main inlet port leading into .said chamber, a valve for controlling said port having unequal fluid pressure acting against its opposed faces and continually urging said Valve to its closed position, Aand a conneotion between said valve and tool permit-ting one to aetuate the other, the unbalanced pressure acting against said valve being of siiiiieient force to move said tool to its outward position.

ln Witness whereof l subscribe my signature7 in the presence of two Witnesses.

OLVER O. APP.

Witnesses:

@Vamo CHAPIN, Josnri-i A. BUoiiiair.

Images