US1058268A - Internal-combustion percussive engine. - Google Patents

Description

L. L. SCOTT. INTERNAL COMBUSTION PERGUSSIVE ENGINE. APPLIUATION FILED 111111.11, 1912.

1,058,268., Patented Apr. 8, 1913.

ATTORNEY thereof;

i .UNITED sTATEs PATENT ormoni .4 I LEWIS L. SCOTT, 0F ST. LOUIS, MISSOURI, ASSIGNOR TO SCOTT LOUIS, MISSOURI, A CORPORATIONOF MISSOURI.

DRILL COMPANY, OF ST.

INTLRruir.-colvmusrronA PERcUssIvE ENGINE."

Patented Apri s, 1913.

Application led March 1i, 1912. Serial No. 6&3,015..

To all whom t may concern.'

Be it known that I, LEWIS L. SCOTT, a citizen of the United States, residing at St. Louis, Missouri, have'invented a certain new and useful Improvement in Internal-Combustion Percussive Engines, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same, referencebeing had to the accompanying drawings, forming part of this specification, in' which- Figure 1 is' a vert-ical longitudinal section of an engine constructed in accordance with my invention. Fig. 2 is a sectional view on line A-A of Fig. 1. Fig. 3 is a top plan View partly in horizontal section. Fig. 4 is a sectional view on line B-#B of Fig. 2.

This invention relates to improvements in internal combustion percussive engines intended to be used particularly in connection with rock drills and the like.

The object of my present invention is to provide means for lholding the explosive pressure within the firing chamber until the piston strikes the end of the block or drill so as to obtain the driving blow on the end of the saine.

Another object is to provide improved means for cushioning the connect-ion between the piston and crank-shaft, the hammer piston being free from the crank shaft when the blow is struck.

In the drawings, l indicates the cylinder and 2 the explosion chamber at the rear end 3 is the compression chamber which receives the charge of ,mixed air and gas through port 4 and channel 44.

5 is t-he head which closes the front end of the chamber in cylinder 1 and 47 is the head which closesthe rear end of said cylinder,

. the latter head being ported and providing a mount for check valve 37 held to its Seatby a spring 38 whereby the compressed charge of air and gas is admitted to the chamber 2. Head 5 affords .a mount for means for r0- tating chuck 6. Y l

7 indicates a piston adapted to reciprocate in cylinder 1,said piston having a hammer head S designed to strike a block 9 mounted in head 5 through which the blow is transmitted to the drill 10.

Where it is desired to rotate the drill lugs i 11 are provided on drill 10, lwhich lugs t in slotsl in the chuck 6 s0 that if the chuck is rotated the drill is rotated in unison therewith. Chuck 6 is provided with Worm te'eth 12, preferably at its inner end, .and which operate in an internal for circumferential groove in the head 5 which Worm teeth -mesh with a worm 13 mount/eden a shaft- 14.4

Shaft 14 is intermittently rotated by means of an eccentric 15 'carried by the main shaft 16 so as to oscillate the yoke or rock arm 17 (mounted on the end of shaft 14) by means of the connect-ing pitman rod 18. The oscillation of arm 17 intermittent-ly rotates4 i shaft 14 by means of a ratchet' and pawl mechanism or by means of collar 19 mounted on the shaft 14 and held in frictional engagement with said shaft by a spring 20 bearing therebetween and a collar 21 threaded on the shaft. This collar 19 has a clutch face engaging a clutch member 19a on shaft 14, as shown in Fig. 2. A roller 22 is mounted in the inclined slot 23in the arm 17, as shown in Fig. 4, so that when the arm 17A is rocked in one direct-ion, shaft 14 will be rotated, while the movement of the arm in the opposite "direction permits' the shaft to remain stationary, this recovering of arm 17 causing the roller to be moved against a shoulder 24 in the arm 17. The object of thus providing a friction drive` for the drill is to prevent the breakage of parts in the. event that the drill becomes wedged in the drill hole. l n

Piston 7, before referred to, is bored to receive 'a piston 25,`preferably introduced through the open end of the bore, which rear end is {closed by a removable head 26. A cross pin 27 is carried by piston 25,'the ends of said pin extending through slots 33 in the walls ,ofl the piston 7 and slots 34 in the/walls of cylinder 1 and are connected to pitman rods 28 and29. Rod'28 is connectyed tocrank pin 30 carried by main shaft 16,

while the rod 29 is connected to an eccentric 3l whose throw is equal to that of the crank pin 30. A fly Wheel 32 is mounted upon one end of shaft 1'6.

35 and 36 are ports cut in the side of piston 7 to permit air at atiriospheric pressure to enter the spaces 45 and 48 between the ends of pistons 7 and 25. These ports are located a little distance from the end of the chamber in the piston 7 se as to provide a vio euehien between are pistone fr ena' 25, ee Win be explained later, although 1n practice it is not absolutely necessary to .use the cushion chamber 48.

5 The charge of mixed air and. gas enters chamber 2 of cylinder 1 through valve 37 which valve is normally held closed by spring 38, before referredto.

39 indicates an exhaust valve for the spent gases, said valve being normally held closed by means of a spring' 40. This valve 39 may be dispensed with if desired.

41 indicates a cam secured to shaft 16 and which coperates with the roller 42 on the 1.5 end of the valve rod 43'which carries the valve 39. Any form of mixing valve may be attached to port 4.

The operation is as follows: The mixed air and gas is drawn into chamber 3 through 20 port 4 and 'channel 44 on the retracting by means of a spark arrangement commonly used in gasolene engines. Piston 7 will now be driven outward under the pressure of the explosion and' will, through the hammer head 8, strike the block- 9, theblow being transmitted to the ydrill 10. Hammer 8 strikes block 9 before crank 16 reaches its dead center and also before the pressure isrelieved in chamber 2 by valve'39. The momentum of the fly wheel causes the crank to continue its movement so that piston 25 will move outward independently .of the piston 7 and allow thecrank shaft to pass its dead center without the end of piston 25 contacting with piston 7 and therefore without shock to its bearings as the'air between the end -of piston 25 and piston 27 forms av cushion. As the piston 25 moves outwardly it uncovers port 36 and lets air at atmospheric pressure enter space 45 between the two pistons, and thus an effective cushion between the pistons on the return stroke is provided which cushions the piston 25 against the shock of the explosion behind piston 7. The exhaust valve is opened and closed during the outward independent movement of piston 25, and as the crank passes its dead center and starts on the back stroke, piston 25 will compress the air in chamber 45 until the piston 7 is caused to move-therewith. Port 435 is uncovered on the back stroke and air at atmospheric pressure will enter the chamber 48 so as to provide a cushion between the outer ends vof the two 65 pistons to absorb any shock due to a reigo'aaeea' bound of piston 7 in striking ,its blow. As these operations continue, it will be apparent that explosions occur in chamber 2 on every out stroke and when piston 7 approaches the end of its out stroke it will, through its energy, strike the block 9 and at the time of delivering such a blow be absolutely free from the crank shaft. At the time of striking its blow the explosive pressure is behind the pist-on 7, thereby making the blow very effective. rllherotation of the drilling tool .will occur, as before described and water or air may be run through the steel drill forv the purpose of removing 'cuttings from the drill hole, connections for same being made 30 lat 46 (Fig. l). In operation piston 7 practically becomes a floating piston entirely in-` dependent from the crank shaft and its bearings and has a dilferential stroke withrespect to the internal piston 25. rIhe stroke of piston 25 is determined by its connections to shaft 1G rand may be said to be fixed.

For purposes distinguished in the following claims I shall designate piston 25 as aninternal piston and floating piston 7 as an external piston.'

What I claim is:

1. In an internal combustionl percussive engine, the combination of a cylinder having valved ports for t-he admission of air and gas and the exhaustion of the spent gases, a floating piston operating in .said cylinder and an internal fixed-stroke piston operating within the floating piston, said pistons being moved in a forward direction by the expansion of exploded gas within the cylinder, and a crank shaft connected with the fixed stroke piston and operable to move the pistons on the rearward stroke.

2. In an explosive engine of the character described, the combination of a' cylinder, a floating piston therein, an internal fixed stroke piston, .said pistons having differen tial movement, lsaid cylinderbeing adapted for the explosion of gas therein to move said pistons, means for providing cushions between the .ends of said pistons, a shaft rotated by the lixed stroke piston on the forward movement of the pistons and operating to return the pistons on the rearward stroke, and means for controlling the admission and exhaust of gas to and from the cylinder.

3. In an explosive engine of the character described, the combination of a cylinder, a floating piston therein adapted to cooperate with a drilling device, an internal piston, a drilling device for receiving a blow from the external piston, a shaft rotated by the internal piston, an exhaust valve, and means operable by said shaft for opening the exhaust valve after the external iston has delivered its blow upon the drilllng device. e'

4..In anexplosive enginexof the character. described, the combinationv of a cylinder,

an external lioating piston'a'ndl anlnternal. 13

fixed-stroke piston, a drilling device with.

. which the loatlng piston coperates, a shaft connected to the internal piston, and means l operated by said" drilling device.

5. In an explosive engine of the character described, the combination of a cylinder, an external Heating piston and an lnternal fixed-stroke piston, a hammer blockwith which the floating piston coperates, a'shaft shaft for rotating said connected to the internal piston, a drill ranged within the floating piston, 'a pin carrie by said internal piston, and having an end projecting through said alined slots, a shaft, and connections between said pin andl shaft for driving the latter.

In an explosive engine of the character described, the combination of a cylinder, a drilling device mounted p cylinder, two istons mounted. within the cylinder, one o said pistons being arran ed within the other, one of said pistons belng in the nature of a fioatin signed to operate the dri ing device, the oter of said pistons having a fixed stroke, a crank shaft piston and adapted to move said pistons away from the drilling device, and means for providing al cushion between said pls-- tons.

8. In an explosive engine of the character described, the combnatlon of a slotted cylinder, a. drilling device mounted in one end of saidcylinder, two pistons arranged withoneof said istons being contained by the other, one o said pistonsbeing in the nature of a fioating piston adapted to strike the drilling device, and the other of said pistons having a fixed stroke, a crank shaft adapted to receive energy from said pistons on their forward stroke for the purpose of moving them on their rearward stroke, and a pin carried by said fixed stroke piston to deliver impactupon at one end of thev piston and deoperated by the last mentionedl e ing piston. coperates andl projecting through the Vslotted cylinder, and connected to said shaft to dperate the same. A

`9. In a device of the class described, the combination, of a cylinder provided with an ex losion chamber, a oating piston in said cy 'nder in operative relation to said explos1on chamber, an anvil with which said floating piston coperates, an inner piston slidingly mounted in said floating piston, a crank the explosion chamber, and means for operating said shaft from said inner piston.

shaft for moving said pistons toward 10. In a Vpercussive engine of the characy ter described, the combination of a cylinder having-anv explosion chamber and a charge receiving chamberzo means for introducing an explosive duid `1nto the charge-receiving chamber and transmitting said fluid to said explosion chamber, means for exploding the fluid in the explosion chamber,two pistons arranged withln the cylinder, one of said pistons being mounted within the other, said diEerential moveplstons having relatively istons bein ment, one of said liver impact, and the other having a fixed stroke, a drilling device for receiving a blow from the fioatin piston, and a crank shaft operated by the ing the pistons on the rearward stroke. Y

11. In a ter described, .in combination, a cylinder providedwith an explosion chamber and a charge receiving chamber, said chambers betion whereby a charge may be conveyed from the latter to the former, a Heating piston operating within said cylinder and ada ted to deliver blows under the inuence of charges exploded inthe explosion chamber, a drilling device with which said ioata fixed stroke piston adapted to move with said Boating piston, and a crank shaft operatively connected with said xed stroke piston whereby said pistons are retracted on their rearward stroke. g

In testimon whereof I hereunto ax my si ature in e presence of two witnesses,

, this 7th day of March, 1912.

, LEWIS vL. scorn` Witnesses:

M. P. Smm, C. S. Bum

percussive engine of the characing provided with a means of communicain the na` I Vture of'a oating piston and a' apted to dexed stroke piston for movv

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