US2446830A - Percussive apparatus - Google Patents

Description

1948- c. A. HIRSCHBERG 2,446,830

PERCUSS IVE APPARATUS Filed March 2, 1945 2 Sheets-Sheet l INVENTOR. 62w! A. Ez'nsdlezy,

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- Alta 717g 1948- c. A. HIRSCHBERG 2,446,830

PERCUSSIVE APPARATUS INVENTOR. CJarles Afihscffiez' Patented Aug. 19, 1948 NlTED STATES TENT OFFICE 3 Claims. 1

This invention relates to improvements in percussive apparatus such as rock drills, automatic hammers, and like impact producing mechanisms, whereby the means for imparting impact upon the drill steel or other tool to be actuated is of the explosive or internal combustion engine type.

The invention has for an object to provide a percussive apparatus of the kind above referred .to comprising an impact delivering means slidably reciprocable in a cylinder, with the upper portion of said means and of said cylinder operating to provide the piston and explosive chamber of an internal combustion engine, a crank-shaft having a fly-wheel, and said impact delivering means being provided with novel axially aligned means adapted to so cooperate with said crank-shaft that the latter is automatically connected and disconnected with said impact delivering means in timed relation to the power stroke thereof, whereby the initial phase of said power stroke is utilized to actuate the fly-wheel. the impact delivering means being thereupon freed to complete itspower stroke unimpeded by the crank-shaft, and finally whereby the inertia of motion of the fly-wheel reengages the crankshaft with the impact delivering means to effect the return or recovery stroke thereof; the aligned relation of said crank-shaft engageable means with the central longitudinal axis of the impact delivering means being adapted to avoid transmission of side thrust to the latter, thus reducing frictional resistance to its reciprocable movements to a minimum.

Another object of this invention is to provide in percussive apparatus of the kind referred to an internal combustion engine means of the two cycle type for producing the power stroke of the impact delivering means, wherein the cylinder and piston structure is of compound form comprising a main piston operative in the explosion chamber of the cylinder and a diametrically enlarged secondary piston operative in a correspondingly enlarged fuel mixture induction chamber of said cylinder, means being provided for delivering a fuel mixture to said induction chamber, and means being provided for transferring the fuel mixture from said induction chamber to the explosion chamber of the cylinder.

Other objects of this invention, not at this time more particularly enumerated, will be understood from the following detailed description of the same.

An illustrative embodiment of the invention is shown in the accompanying drawings, in which:

Fig. 1 is a longitudinal sectional View of percussive apparatus according to this invention, the impact delivering means being shown in elevation, and at the top of its recovery stroke; Fig. 2 is a similar view, with parts broken away, and showing the impact delivering means at the end of its power stroke; Figs. 3 and 4 are similar fragmentary views, respectively showing progressive phases of the crank-shaft movement operative to effect a recovery or return stroke of the impact delivering means; and Fig. 5 is a longitudinal sectional view, taken on line 5-5 in Fig. 1, parts being broken away.

Similar characters of reference are employed in the above described views, to indicate corresponding parts.

Referring to the drawings, the reference characters i9 and II respectively indicate upper and lower sections of a cylinder, which are suitably connected together in axially aligned, end to end relation.

The top part of the upper cylinder section In is provided witha bore of suitable diameter, whereby to form an eXplosion chamber l2. The top end of said explosion chamber i2 is closed by a cylin-, der head l3, which issuitably secured to the top end of said upper cylinder section lll That portion of the walls of said upper cylinder section 10 which bound the explosion chamber I2 may be cored to provide internal spaces or passages lli through which a cooling fluid may be circulated, if so desired. Below the explosion chamber i2, said upper cylinder section in is provided with a second bore of enlarged diameter and suitable length, whereby to provide a fuel mixture induction chamber l5. upper cylinder section Hi and the entire length of the lower cylinder section If is provided with a bore l6 which is preferably, but not necessarily,

somewhat larger in diameter than that of the.

fuel mixture induction chamber l5. Said bore It provides a slideway for the guide piston portion of the impact delivering means of the ap paratus hereinafter described.

The impact delivering means of the apparatus is slidably reciprocable within the above described cylinder structure and comprises a unitary structure provided at its upper end with an engine piston l'l adapted to slidably fit the explosion chamber 12 so as to reciprocate therein. Spaced from and below said engine piston i7 is a fuel mixture control piston l8 adapted to slidably fit the fuel mixture induction chamber l5 so as to reciprocate therein. Said fuel mixture control piston I8 is connected with the engine piston 11 by an intermediate axial shank portion I9 of substantially.

The lower part of said reduced diameter; being smaller in diameter than said engine and control pistons. At its lower end, the impact delivering means is provided with a guide piston 20 adapted to slidably fit the bore I6 of the cylinder structure so as to reciprocate therein. Extending between said fuel mixture control piston I8 and said guide piston 20 is a cam-frame 2| of suitable width, the same being disposed in a transverse plane intersecting the longitudinal axis of the impact delivering means. The upper end of said cam-frame is unitarily connected with the fuel mixture control piston I8 by an upper neck portion 22. The lower end of said cam-frame is unitarily connected with the guide piston 20 by a lower neck portion 23. Said cam-frame is provided with a circular opening which defines a lift cam member 24. Leading tangentially from said opening, so as to extend outwardly and upwardly therefrom is an extension of said opening adapted to provide a longitudinal slideway 25.

The cylinder structure is provided at opposite sides thereof with bearing portions 26 which are aligned on a transverse axis extending at right angles to the plane of said cam-frame 2 I. Jour-- naled in and between said bearing portions 26 is a crank-shaft 2'1. Said crank-shaft is provided with spaced crank-arms 28 adapted to straddle the cam-frame 2|. Extending between the outward ends of said crank-arms 28 is a crank-pin 29 upon which is mounted suitable anti-friction means 30. Said crank-pin 29 and its anti-friction means 30 extends through the opening of said cam-frame 2|, whereby to cooperate with the lift cam member 24 of the latter. Said crankshaft is provided with an outer end portion 3| arranged to extend exteriorly from the cylinder structure, and fixed on said outer end portion 3| is a fly-wheel 32.

Connected with the upper section II] the cylinder structure is means for admitting a fuel mixture into the fuel induction chamber I5. This means comprises a valve casing 33 having a passage 34 terminating in an inlet port 35 which communicates with the interior of the fuel induction chamber I5. Said inlet port 35 is normally closed by an inwardly opening spring closed valve 36. Connected with the intake end of the valve casing passage 34 is a fuel mixture delivery conduit 3'! which leads from a suitable carburetor device (not shown).

Also connected with the upper section I of the cylinder structure is means for transferring a fuel mixture from the induction chamber I to the explosion chamber I2. This means comprises a by-pass housing 38 having an outlet port 39 leading from the interior of said fuel induction chamber I5 to a valve chamber 40. Said outlet port is normally closed by an outwardly opening spring closed valve 4|. Said valve chamber 40 communicates with a fuel mixture receiving chamber 42. Said receiving chamber 42 communicates with the explosion chamber I2 through a fuel admission port 43.. Said admission port 43 is closed by the engine piston II, but is opened temporarily when the top end of said engine piston II passes the same as said engine piston, in descending. completes its down or power stroke. The upper section of the cylinder structure is provided, in a side thereof opposite to that at which said admission port 43 is located, with an exhaust port 44; said exhaust port being likewise located so as to be opened temporarily when the top end of the engine piston I! passes the same as said engine piston, in descending, completes its down or power stroke. Suitably arranged to enter the explosion chamber I2 is a spark plug 45, which is adapted to be electrically controlled and operated in a manner well known; or any other suitable form of explosive charge ignition means may be provided.

The lower section II of the cylinder structure terminates in a tool receiving member 45 having a suitably shaped and bushed throat member 41 provided with an axial passage 48 to receive the shank end portion 49 of a drill steel 50 or other impact operated tool. Projecting downwardly from the guide piston 20 is an axially aligned striking member 5| adapted to be reciprocated with the impact delivering means of the apparatus, whereby, upon operation of the latter, to intermittently strike the steel or tool with forceful driving blows.

Connected with the free end of the tool receiving member 46 is a drill or tool retaining and aligning means, which may optionally comprise a manipulatable coupler body structure 52 of the kind fully disclosed in my copending application for Letters Patent Ser. No. 553,164, filed September 8, 1944, now Patent No. 2,430,716, or one of any other known type.

In operation of the apparatus, on a down-stroke of the fuel mixture control piston I8, a reduction of pressure occurs in the induction chamber I5 so that the valve 36 is caused to open, thus drawing from the delivery conduit 31 and through the valve casing passage 34 the fuel mixture from the supply thereof, and admitting the same into the induction chamber I5 through the opened inlet port 35. On an up-stroke of the piston I8, the valve 36 closes the inlet port 35, and the fuel mixture within the induction chamber I5 is, by compression, driven outwardly therefrom through the outlet 39. The pressure of the outgoing fuel mixture opens the valve M, and admits the fuel mixture to the receiving chamber 42. Since the piston I8 and the engine piston I! are unitary and move together, the rising movement of the engine piston closes the fuel admission port 43 which leads from the receiving chamber 42 into the explosion chamber I2 of the cylinder structure (see Fig. 1), and consequently the fuel charge, delivered into the receiving chamber 42 by the rising movement of piston I8, is trapped and temporarily held in said receiving chamber, pending a succeeding descent or power stroke of the engine piston I'l induced by the firing of a previously admitted fuel charge compressed within the explosion chamber I2 during the aforesaid rising movement of said engine piston. As the engine piston I! completes its descending or power stroke movement, it passes and thereby opens both the exhaust port 44 and the fuel admission port 43 (see Fig. 2), thereupon the fuel mixture charge previously stored in the receiving chamber 42 rushes into the explosion chamber I2 and displaces the spent gases of combustion by discharging the same through the exhaust port 44. The above described sequence of operations is successively repeated, whereby the apparatus is provided with a power producing agency of the two-cycle internal combustion engine type.

As viewed in Figs. 1 to 4 inclusive of the drawings, the crank-shaft 2'! and fly-wheel 32 are arranged to rotate in anti-clockwise direction. Since the cam-frame 2| is unitary with the described engine pistons, so as to reciprocate in company therewith, when said cam-frame 2I and engine pistons reach the limit of up-stroke movement, the crank-pin 29 reaches and somewhat passes the limit of its up-swinging' movement, and is moving toward the slideway 25 of the camframe 2!, but has not cleared or moved out of contact with the lift cam member 24 of said camframe. The firing of an explosive charge within the explosion chamber 52 is timed to occur when said parts are in such relation, whereupon the resulting explosion in the explosion chamber drives downward the engine pistons so as to effect a power stroke thereof, and thereby transmitting a down-thrust to said cam-frame 2| connected therewith. Such down-thrust of the cam-frame exerts a like power transmitted down-thrust or kick to the crank-pin 29 and crank-arm 28, thus transmitting to the crank-shaft 2'5 and fly-wheel 32, a rotating impulse operative to renew inertia of motion thereof. After receiving such thrust or kick, the crank-pin 29 moves into alignment with the slideway 25 of said cam-frame 2 i, thereby allowing the impact delivering means to move freely downward in the cylinder structure, unimpeded or unhampered by the crank-shaft 27. The impact delivering means being thus freed during the completion of its power stroke, its descent is only limited by contact of the striking member 5! thereof with the drill steel or tool 49-50, and consequently a power induced impact of said striking member upon the latter delivers thereto an operating blow of considerable force.

While the impact delivering means is completing its power induced descent, the inertia of movement of the revolving fly-wheel 32 continues the revolution of the crank-shaft 21!, whereby to complete the down-swinging movement of the crank-pin 29, and thereupon cause the same to enter upon its up-swinging movement, so that by the time the impact delivering means reacts from the blow transmitted thereby to the drillsteel or tool, the ascending crank-pin 29 will meet and engage the lift cam member 24 of said camframe (see Fig. 3). After the crank-pin 29 engages the cam-member 24, continued ascent of the former in contact with the latter under the inertia of movement of the fly-wheel 32, will exert an up-moving effect upon the impact delivering means (see Fig. 4), until up-stroke thereof is completed and the above described cycle of operations is repeated.

It will be observed that the cam-frame 2i and the cooperating crank means of the crank-shaft 21 are centrally aligned between opposite sides of the cylinder structure, and thus in axial alignment with the reciprocable impact delivering means of the apparatus. As a consequence of this the up-thrust transmitted by the crankshaft through the cam-frame to the piston members of the impact delivering means is centrally applied along the axis of the piston members, whereby side thrust is eliminated and cant-ing or tilting of the piston members is avoided. By reason of this, undue frictional resistance to longitudinal movement of the impact delivery means is avoided, and wearing of the cylinder structure walls and piston member sides out of true is substantially reduced if not entirely prevented. This is a factor contributing greatly to smooth action of the apparatus in use, as well as prolongation of its useful life.

It will be further observed, that the described construction provides a very compact, simple and highly efiicient percussive apparatus of the type wherein the power generating agency is of the internal combustion engine type.

Having now described my invention, I claim:

1. In percussive apparatus having a power 6. generating agency of the internalcombustion enginetype, a cylinder structure the upper portion of which constitutes an explosion chamber, a unitary impact delivering means re'ciprocable' iin said cylinder structure comprising engine piston means movable in said explosion chamher, a guide piston movable in the lower portion said cylinder structure, a cam-frame centrallyaligned between opposite sides of the cylinder structure intermediate and in axial alignment with said engine piston means and said guide piston, and a striking member unitary with projecting axially downwardly .from said e piston, said cam-frame having a circular H218, the perimeter of which provides a lift cam member, and a slideway leading tangentially upward from said opening parallel to the longitudinal axis of the impact delivering means, reby to permit free movement of the latter during the end phase of its operative stroke, a crank-shait journaled across said cylinder structure, the crank-pin of said crank-shaft extending through said cam-frame opening and being cooperative with the cam member formed by the perimeter of the latter, a fly-wheel affixed to an exterior end of said crank-shaft, and means at the lower end of said cylinder structure to hold a tool to be actuated in the path of and subject to the impact of said striking member.

2. In percussive apparatus having a power generating agency of the internal combustion engine type, a cylinder structure having an upper portion of reduced cross-sectional area to provide an explosion chamber having a fuel mixture admission port and an exhaust port, said cylinder structure having a portion of relatively enlarged internal cross-sectional area immediately below said explosion chamber adapted to provide a fuel mixture induction chamber, valved fuel mixture admission means communicating with said induction chamber, valved fuel mixture outlet means leading from said induction chamber, a fuel mixture receiving chamber in communication respectively with said outlet means and the admission port of said explosion chamber, in which a fuel charge is temporarily stored and compressed, a unitary impact delivering means reciprocable within said cylinder structure comprising an engine piston movable in said explosion chamber, a fuel mixture control piston movable in said induction chamber, a guide piston movable in the lower portion of said cylinder structure, a cam-frame centrally aligned between opposite sides of the cylinder structure intermediate and in axial alignment with said fuel mixture control piston and said guide piston, and a striking member unitary with and projecting axially downwardly from said guide piston, said cam-frame having a circular opening, the perimeter of which provides a lift cam member, and a slideway leading tangentially upward from said opening parallel to the longitudinal axis of the impact delivering means, whereby to permit free movement of the latter during the end phase of its operative stroke, a crank-shaft journaled across said cylinder structure, the crank-pin of said crank-shaft extending through said cam-frame opening and being cooperative with the cam member formed by the perimeter of the latter, a fiy-wheel affixed to an exterior end of said crank-shaft, and means at the lower end of said cylinder structure to hold a tool to be actuated in the path of and subject to the impact of said striking member.

3. In percussive apparatus having a power generating agency of the internal combustion engine type, a cylinder structure the upper portion of which is of stepped bore to provide an upper explosion chamber and a lower fuel mixture induction chamber, means to admit a fuel mixture into said induction chamber, means to by-pass fuel mixture from said induction chamher to said explosion chamber, a unitary impact delivering means reciprocable within said cylinder structure comprising a compound engine piston means movable in said explosion and induction chambers, a guide piston movable in the lower portion of said cylinder structure, a camframe centrally aligned between opposite sides of the cylinder structure intermediate and in axial alignment with said engine piston means and said guide piston, and a striking member unitary with and projecting axially downwardly from said guide piston, said cam-frame having a circular opening, the perimeter of which provides a lift cam member, and a slideway leading tangentially upward from said opening parallel to the longitudinal axis of the impact delivering REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 20 Number Name Date 1,642,949 Gilman Sept. 20, 1927 1,977,645 Roberts Oct, 23, 1934 2,333,419 Fitch NOV. 2, 1943

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