US2223095A - Internal combustion drill - Google Patents

Description

INTERNAL COMBUSTION DRILL Nov. 26, 1940. c, r| CHARLES 2,223,095

INTERNAL COMBUST ION DRILL NOV. 26, 1940. Q L. CHARLES 2,223,095

INTERNAL COMBUSTION DRILL Filed July 10, 1957 4 Sheets-Sheet 5 Nov. 26, 1940. C, CHARLES 2,223,095'

INTERNAL COMBUSTION DRILL Filed July 10, 1937 4 Sheets-Sheet 4 i Y Zz/'eW/(Z'LW f A 7,15 65 @gri l fW/e@ Patented Nov. 26, 1940 UNITED STATES INTERNAL coMBUs'rroN DRILL Carl L. Charles, Winnetka, lll., assigner to Gas Tool Patents Corporation, a corporation of Delaware Application July 10, 1937, Serial No. 153,049

Claims. (Cl. 121-7) This invention relates to an internal combustion drll1, and more particularly to 'an improved form of such a drill.

One feature of this invention is that means 5 are provided for rotating the tool during drilling; another feature of this invention is that the rotating means is operated without the necessity of an independent supply of power, although the power forthe drill is explosive in character; yet

lo another feature is that the tool is rotated during the return stroke of the piston-hammer; a further feature is that the body of the drill is so arranged as to provide improved cooling for the piston return spring; other features andl advantages of this invention will be apparent from the following speciiication and the drawings, in which:

Fig. 1 is a vertical view, principally in section, of a drill embodying the invention disclosed herein; Fig. 2 is a fragmentary transverse sectional view along the line 2-2 of Fig. l; Fig. 3 is a horizontal sectional view along the line 3 3 of Eig. 2; Fig. 4 is a horizontal sectional view on the line --il of Fig. 2; Fig. 5 is a view looking upward along the line`5-5 of Fig. 2; Fig. 6 is a sectional view of the groove along the line S-- of Fig. 2; Fig. '7 is a sectional view of the compression chamber along the line 'I--l of Fig. l; Fig. 8 is a fragmentary sectional view of a modied form of the lower end of the drill; Fig. 9 is a transverse sectional View along the line @-9 of Fig. 8; and Fig. l0 is a View along the line l-l@ of Fig. 8.

The drill disclosed herein is an internal comgg bustion hammer of the free piston type. In the whereby impacts from the piston hammer l2v during operation of the drill are transmitted to the tool I4 to effect the desired work. Tool-rotating means is provided at the bottom of the hammer, and will be more fully described hereafter.

The cylinder I I has, adjacent the anvil housing I3, a portion having radial grooves or notches I 6, which form a space or compression chamber adapted to have a combustible charge furnished thereto from the charge-forming unit II, here shown as comprising a gasoline tank and carburetor, through an intake port not here shown. A transfer passage I8. in cooperation with the openings I9 through the piston d2, provides means for transferring the combustible charge to the combustion chamber 20 above the piston, where the charge is finally compressed on the upstroke of the piston and red by a spark-plug 2l at a time determined by the timer device 22. The tiring of this charge results in the downward or working stroke of the piston, which compresses the return spring means 23 and at the end of its travel strikes the anvil l5 to transmit a sharp blow to the tool i4. The energy stored in the return spring 23, aided by the rebound from the anvil, then returns the piston to repeat the operation. The drill or hammer is thus seen to work on the conventional two-strike cycle internal combustion principle.

A pair of handles 2i and 25 are provided to enable the operator to properly locate the tool lf3 at the beginning of the drilling operation, and to maintain the travel of the tool in the desired direction during drilling. A starting rod 2S enables the device to be conveniently started, since manual depression of this rod depresses the piston i2. One or two operations of this rod thus draws in a charge, transfers it to the combustion chamber, and fires it to initiate operation of the drill. Ignition current is supplied from an outside source, not here shown, through the cable 2l entering the drill through the handle 24.

While drills of this general type are known in the art, they have been open to several objections. ln the rst place, the return spring means 23 has heretofore contacted the piston I2 directly, and has been customarily placed in the subpiston compression chamber. Such construction permitted the direct conductive transfer of the heat of explosion through the piston to the spring, and resulted in excessively high spring temperatures during operation. The nature of these temperatures may be realized from the fact that the outside walls of the cylinder I I, even though provided with cooling ns, frequently attain temperatures of iive to six hundred degrees Fahrenheit when the device is working. Considerable difliculty with spring breakage was long encountered in devices of this type, and it was learned that the excessive temperatures of the spring contributed greatly to this diiiiculty.

The present invention provides improved means for cooling the spring by placing it in a portion of the cylinder or bore separated not only from the piston but even from the subpiston compression chamber by an inverted cup member 28. This member is here shown as in closely fitted slidable contact with the internal wall of the anvil housing I3, so that-even when the piston and member are at vtheir uppermost position the portion of the bore in which the spring 23 lies is completely sealed from the compression chamber.

The anvil housing is so arranged as to permit circulation of air therethrough during operation of the drill, being here shown as provided with a pair of valved openings 23 and 30. These valvesare so arranged that during upward travel of the member 2s air is drawn in through the' opening 29, and during downward travel thereof on the working stroke of the piston this air is expelled through the opening 30. Thus, cooling air is constantly passing around the coils of the return spring means'23, and this spring is very eiilciently cooled. Even' though lthe member 28 is in conta'ct with the piston I2, the fact that it is exposed to the cooling influence of air on its inner side and of the incoming fresh charge on its 'outer side prevents undue direct transfer of heat. While the bore is slightly larger in the compression chamber to provide suiilcient room for`the desired volum'e of charge, this space is here shown as increased by the previously mentioned radial grooves I3.- The outer edge of the member 23, moreover, is tapered to permit admittance of the charge to the openings I3 in the piston, through which openings it is delivered to the transfer passage I8 when the piston registers therewith.

In order to drill to any depth into a substance such as rock it is necessary to rotate thetool f during the drilling operation, s o that it will cut a substantially flat bottom surface rather than wedging itself into the rock. In order to ac-v al tool-rotating means of the type-knownand used in connection with pneumatic drills cannot be adapted to an internal combustion drill of the free piston type, since they operate on either' the rifle bar principle or make' use of the expansive force of some uid such as air \or steam.

Where a rie bar is used, the actual Work cgi/ rotating the tool is done on the up or return,`

stroke of the piston, and it is impracticable for the return spring 23 'to be of suicient strength to accomplish such rotation. The explosive force of the combustible charge, of course, is not adapted to operate drill rotating motor means of the type used in air'vhammers, for example.

The present hammer includes automatic mean for rotating the tool during drilling, the rotation being accomplishedduring the return or upstroke of the piston but the energy therefor being delivered during the working stroke ofthe piston. That is, near the termination of its working stroke the piston stores a certain amount of energy byplacing one or more springs under strain, and as soon as the piston starts on its upward stroke this stored energy effects rotation of the tool. Rotation of the tool immediately after a blow has been struck, is, of coursethe preferable time, since the tool has then rebound- Referring more particularly to the embodiment of this drill-rotating means here disclosed. it will be seen that the anvil t5 has an expanded lower portion, which portion is provided with'grooves 3l and 32 adapted to slidably contact and be splined on portions of the tie- rods 33 and 34 exf tending longitudinally of the drill on opposite sides thereof. rThe anvil isv thus non-rotatably mounted in the drill body, but is so arranged as to permit limited movement longitudinally thereof. In this connection, it will be understood that all reference as to direction of motion of various parts is made on the basis of the drill here shown, and if the placement of the drill in general be changed; the absolute direction of such motions should .be considered changed in accordance therewith.

. Beneath the anvil and carried by the housing 35 is a rockable member 33, such member being arranged to rock or oscillate about an axis coinciding with that of the tool I4.` Thelower surabove.

' The housing 35 carries on opposite sides thereof a pair of cylinders 4I and 42, in' which slide longitudinally movable plungers 43 and 44. of coiled springs 45 and 43 are arranged under compression, so that movement of the plungers 43 and 44 serves to store energy therein. The rockable member 33 is provided with a pair of shoulders 41 and 43 adapted to lie in cooperating relation with shoulders 49 and r5I) on the plungers 43 and 44, respectively. Anti-friction members 5| and 52, Ahere shown as steel rollers, are interposed between the shoulders 41 and 49 and 43 and 50. It is thus apparent that clock'- wise` rotation of the rockable member 33 (with particular reference to Fig. 3) will cause movement of the plungers 43 and 44 to place the .springs 45 and 43 under compression strain,

and thus to store in them' energy imparted from the pistonl through longitudinal movement of the anvil. This longitudinal movement of the anvil, ofcourse, is the striking movement which imparts the blow to the tool I'4.

As soon as the blow of the piston has been completely absorbed, the rebound and the return spring 23 start it upwardly out of .contact with the anvil, and the energy stored in the springs 45 and 43 is then able to move the rockable member 36 in a counter-clockwise direction to return it to its original position.

A4 pair Although the tool I4 vprojects through" the I rockable member 36, it is loosely mounted therein, and does not move therewith. Instead, a clutch member 52 is provided which is non-rotatably splined to the tool I4. This clutch member is rotatable within the rockable member 33 in one direction only, rotation'in the opposite ldirection being prevented by the action of the spring-urged rollers 53 with the surfaces 54,

which converge toward'the inner surface of the rockable member 36. Y Thus, rocking or oscillating of the member 33 results, through the interable member rotates in a. clockwise direction (again looking down from above), it merely idles with respect to the' clutch member 52, the tool standing still in the hole as a result of the fricf tion of its contact with the rock. When the springs drive the rockable member back in a counter-clockwise direction, however, the rollers Siserve to lock the members 36 and 52 together, so that the tool is rotated throughout a small portion of arc. The use of a clutch of the type disclosed is highly advantageous, since any small movement of the rockable member is suiiicient to cause the desired rotation of the tool. Were a conventional ratchet device to be used, it would be necessary to( have a considerable range of motion of the rockable member to insure engaging the next tooth of the ratchet device, orA else the teeth would have to be so small or so 'close together as to result in frequent breakage thereof.

It will be seen that a very eiiicient and rugged method of automatic drill rotation /is thus provided in the embodiment of the'drill disclosed herewith. Various parts are balanced so that undue transverse strains are not imposed on the mechanism. That is, there are two links on opposite sides whereby-longitudinal movement of the anvil istransformed into rotational move,- ment ofthe rockable member; there are two springs on opposite sides in which the energy is stored; and two connections on opposite sides of the rockable member to balance the translation of its rotational movement into longitudinal movement of the plungers 43 and 44. While thel movement of the anvil member l5 is spoken of as longitudinal or. downward, this is again with reference to the body of the drill. In actual practice, the drill body bounces or jumps somewhat during drilling, as a result of the reaction of the explosion against the cylinder head, and thus the change of relationship between the anvil member and the rest ofthe drill body is really composed partly of downward movement of the anvil and partlyof upward movement of the rest of the drill'body.-

An improved lower end construction achieving automatic tool rotation during drilling is shown in Figs. 8-10. The drill is here shown only in a fragmentary way, the other portions thereof being similar to that illustrated more fully in Figs. 1-7. l

'I'he drill is here shown as comprising a cylinder 60 having journalled therein a sleeve bearing 6l.' This sleeve bearing is longitudinally movable inthe cylinder and abuts a shoulder therein at the upper extremity of its travel, in the position illustrated in Fig. 8. Within the sleeve bearing is mounted for longitudinal movement an anvil 62, which anvil has an enlarged base portion 63 splined on either side on the tie rods 64 and 65, so that it may be Vmoved longitudinally but not rotatably with respect to the v cylinder.

The lower end of the drill carries a rockable .member 6B adapted to cooperate with members lvabout its axis v the .movement ofthe tool is unidirectional only.

` 'I'he expanded portion 63 of the anvil and the rockablemember 66' are-provided with cooperating recesses or sockets, as for example13 and 14..

Links 15 and 16 are here shown as rod members having hemispherical ends adaptedto be received by the sockets. It will be noted that these links -lie at an angle to the movement of the anvil, and

thus serve to translate the longitudinalmovement thereof into rotational movement of the rockable-member, as described in connection with the-'previous-modiflcation of .such a drill. The particular form of links shown here, inconnection 'with' the two-piece anvil, has been found ,to give improvedtranslation of the longitudinal force resulting -from the impact of the piston into the rotational force storing energy in the springs 69 .and 10 to rotate the tool 1|.

The particular modication of this drill shown in Figs. 8-10l also includes means for supplying a iuid under pressure to an opening 11.axial of the tool 1I. vStandard tools of the type used for deep rock drilling, for example, are provided-with the central bores and it is desirable to admit uid under pressure thereto at intervals in order to blow out the dust and the like from the hole to prevent clogging thereof during drilling.

The cylinder 6D of the drill is here shown as provided with a connector 18 adapted to have supplied thereto a iluid under pressure, as for example, by a exible air hose leading from a tank or other source of compressed air. The inner wall of the-cylinder adjacent the sleeve bearing 6l is provided with a groove 19 of a length equivalent to the normal travel of the sleeve bearing. Y

groove 83 adapted to register with the groove 82,

and a T-shaped bore 84 serves to deliver the fluid to the bore or opening 11 in the tool,l registering therewith at. the anvil surface which contacts the upper end of the tool to deliver the impacts thereto. l A

This arrangement provides a path for iiuid under pressure from the connector 18 to the opening 11 in the tool. I'his path is not disturbed by movement of the parts during'operation of the drill, since the annular registering grooves permit the parts to rotate with respect to each other without blocking the ow of uid and the wide groove 19 prevents longitudinal movement of the sleeve bearing 6l without any choking of the flow. This is important, since deep holes are best blown by the delivery at intervals thereto of a come parativelylarge volume of air -in a very brief period. That is, it is desirable to supply a cubic foot or more of air at an initial pressure of fifty and said drill includes a spring for eilecting moveblows from .said piston on the working stroke thereof and transmit them to said tool; a rockable member; means whereby movement otsaid anvil with respect to the drill rocks said member; and clutch means between said rockable member and said tool whereby uni;directional rotation of said tool is effected. l I l 2. Apparatus of the character claimed in'ciaim l, wherein downward movement of said anvil' as a result of the blow offsaid piston eilects movement of said rockable member in one direction,

ment of said rockable member in the opposite di- 3. A percussive drill of the character described,

, including: a cylinder; a piston reciprocable therein; means for eiecting working strokes oi; said piston; a tool; an anvil adapted to receive blows from saidpiston on the working stroke thereof and transmit them to said tool; a rockable member; means whereby downward movement of said anvil as a result of the blow of said piston eects movement of said rockable member in one direction; a pair of opposed springs placed under strain by said movement of the rockable member for eiecting return movement thereof; and clutch means between said rockable member and said tool whereby uni-directionalrotation of said tool is effected, said clutch comprising a spring-urged roller between a pair of converging surfaces.

4. Apparatus of the character claimed in claim 3, wherein the means for eiecting movement of the rockable member comprises a link between said anvil and said rockable-member, said link being inclined to the direction of movement oi said anvil.

5. Apparatus of the character claimed in claim 3, wherein the means for effecting movement of the rockable member comprises a pairy of links received by grooves in said anvil and saidrrockable member, said links tapering toward said yrockable member and being inclined to the direcaasaoes y i by said spring eilects rotation of said toollduring return o1' said piston.

r, 7. A percussive drill of the character described, including: a cylinder; a piston reciprocable therein;` means for effecting working strokes ot said piston; a tool; a sleeve bearing; an anvil longitudinally movable in said sleeve bearing and nonrotatably splined with respect to said cylinder,

said anvil being adapted to receive blows from said piston on the working strokethereof and transmit them to said tool; a rockable member; means whereby downward movementof said anvil as a result of the blow of said piston effects movement of said rockable member in one direction; a pair of opposed springs placed under strain by said movement of the rockable member for effecting return movement thereof; and clutch means between said rockable member and said ltool whereby uni-directional rotation of said tool is eiected, said clutch comprising a springurged roller between a pair of converging surfaces.

8. Apparatus of the character claimed in claim i 7, wherein the means for effecting movement 5f the rockable member comprises a pair of links received by sockets in said anvil land said rock able member and inclined to the direction of movement of said anvil,v said links being rods with spherical end portions. I.

9. An internal combustion drill,of the charreciprocable therein; a tool; an anvil adapted to receive blows from the piston and transmit them to the tool, the anvil being non-rotatably mountted in the drill for limited longitudinal movement; a member mounted for uni-directional rotation, said member having the tool non-rotatably splined thereto; and means connecting the l anvil and the member for translating longitudinal movement of the anvil into rotation oi the member between the blows, including means for storing energy during downward movement of the anvil, and wherein rotation of the tool is ef fected, after it has been struck a blow, by such stored energy.

10. An internal combustion drill of the character described, including: a cylinder; a piston reciprocable therein; aftool; a member interposed between said piston and said tool and adapted lto transmit blows to said tool, said member being longitudinally movable in said drill; meansfor -storing energy during downward movement of the member; and rotatable means for rotating said tool, said means being actuated by the stored energy.

3G, acter described, including: a cylinder; .a piston f

Images