US3845895A

US3845895A - Apparatus for cracking castings

Info

Publication number: US3845895A
Application number: US00447021A
Authority: US
Inventors: Y Nakahara
Original assignee: Nagoya Metal Co Ltd
Current assignee: Nagoya Metal Co Ltd
Priority date: 1974-02-28
Filing date: 1974-02-28
Publication date: 1974-11-05
Anticipated expiration: 1991-11-05

Abstract

An apparatus for cracking castings characterized in that; a cracking piece is placed between a cracking tool and a crackingtool receiving member; the cracking tool is pressed on a piece to be cracked so as to lodge the point of said tool in said piece; an abrupt temperature rise is caused in a press-and-slide portion on which the cracking tool is pressed, a cooling water is injected in a small gap produced between the cracking tool and the cracked face of said piece, thereby rapidly cooling said press-and-slide portion as well as heat affected zone in said piece, for rendering same embrittled; whereby both the physical and chemical actions are concurrently caused.

Description

United States Patent [1 1 Nakahara Nov. 5-, 1974 l l APPARATUS FOR CRACKING CASTINGS Primary ExuminerAndrcw R; Juhasz Assistant ExaminerLeon Gilden 75l tzYtkNkh ,N ,J" E73; 2 or N a M l c Ltj Attorney, Agent, or F1rmKarl W. Flocks ssrgnee: agoya e a 0.,

Nakagawa-Ku, Nagoya, Japan ABSTRACT [22] Flled: 1974 An apparatus for cracking castings characterized in [21] Appl. No.: 447,021 that; a cracking piece is placed between a cracking tool and a cracking tool receiving member; the cracking tool is pressed on a piece to be cracked so as to lll. 225/93.5],3f55 lodge the point of Said tool in Said piece; an abrupt 58 Field nearer11111111115155;555:155, 104, 105, tempeiature is Faused a i Portion 225/2 on VYlllCl] the cracking tool is pressed, a cooling water s in ected in a small gap produced between the crack- [561 References Cited iliiffi'ciilngiaii filisi2355351135lifiis1131 21 UNITED STATES PATENTS heat affected zone in said piece, for rendering same 684,686 10/1901 Grotz 225/935 embritfl d; whereby both the physical and chemical 3)? i ill Z ,5 actions are concurrently caused. e 1C 1 Claim, 5 Drawing Figures APPARATUS FOR CRACKING CASTINGS BACKGROUND OF THE INVENTION This invention relates to a cracking apparatus for use in cracking castings, nonferrous metals or extremely thick plates for reuse and for use in cutting same. More particularly, the present invention relates to an apparatus for cracking castings, wherein when an abrupt temperature rise occurs in a pressand-slide portion between a cracking tool and the lodged face thereof in a piece to be cracked, on which portion a cracking tool is pressed, cooling water is injected into the press-andslide portion with the attendant downward movement of the cracking tool exerting pressure on said piece, whereby both the physical actions and chemical actions are substantially concurrently caused during the cracking operation, thereby instantaneously producing an amazingly strong cracking force of several times as high as the power posessed by the cracking apparatus itself, with the assurance of accurate and efficient cracking for castings, or cutting thereof.

Hithereto, the cracking of castings by the use of the cracking apparatus of the type has resorted to the power posessed by the cracking apparatus alone. For this reason, the cracking ability is low relative to the pressure level used. Beside, the cracking apparatus is extremely expensive. In the meantime, the casting process for cast-iron makes amazing progress to such a technical level that ductile and high strength cast iron permit mass production for commercial demand.

However, the conventional cracking apparatus, in case it is used for cracking or cutting such high strength casting, fails to achieve a satisfactory performance. To cope with such a failure, it is prevailingly practised that the pressure of the cracking apparatus is increased or decreased according to mass of a cracking piece, so as to achieve an intended cracking performance, or that for cracking an extremely thick material, a number of holes are drilled in the material to be cracked, for lodging wedges therein, which is known as so-called a wedge cracking process.

To solve inconveniences encounted, it is an object of the present invention to provide .an apparatus for cracking castings, wherein the physical and chemical structure-breaking actions are utilized so as to produce a cracking force increased to several times as much as that given by the cracking apparatus itself, thereby achieving instantaneous cracking for a material to be cracked.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate a preferred embodiment of the present invention, wherein;

FIG. I is a side elevational view of the cracking apparatus;

FIG. 2 is a front elevational view of the same; and

FIGS. 3(a), 3(b) and 3(0) are enlarged side elevationalviews of an essential part of the cracking apparatus, illustrative of respective step of cracking.

DETAILED DEWCRIPTION OF THE INVENTION A hydraulic pressure type cracking apparatus is shown in the drawings. In FIG. I, a solid line shows a position of a cracking apparatus maintained in stationary condition prior to operation, as well as a position, in which the cracking apparatus has returned after the completion of the cracking operation. The dotted line illustrates a status where a cracking tool is lowered vertically towards a cracking-tool receiving member for exerting pressure on piece to be cracked. Shown at l is a main shaft which is connected to a hydraulic cylinder C and which has a lower end at which is mounted a chuck 2 thereon having a cracking tool P removably secured thereto. The main shaft 1 is so arranged as to be vertically shifted under a remote control. Denoted at 3 are guard plates which are attached in opposite diametrical positions of the lower end of main shaft, i.e., on the operational sides of the chuck 2. Shown at Q is a cracking-tool receiving member which is removably mounted on a bed 5 on which is rested the crackingtool receiving member, which bed is rigidly mounted on a bed plate 4. The receiving member Q is positioned coaxially with cracking tool P. Shown at 6 is a movable, adjusting plate which is provided on the bedplate 4 and which has one end rotatably supported by ashaft 7 on one side of bedplate 4 and the other end coupled by a supporting shaft 11 to a shaft 10 of an adjusting plate actuating hydraulic cylinder 9, said hydraulic cylinder 9 being rotatably mounted by a supporting shaft 8 on the other side of bed plate 4. The movable adjusting plate 6 is permitted, under remote control, to assume any position over a wide range of angles, irrespective of the cracking-tool receiving member Q and receivingmember resting bed 5, so as to locate a piece B to be cracked along the center line of the cracking tool P and cracking-tool receiving member Q, for the convenience of the determination of a cracking point and for facilitating the removal of cracked pieces therefrom. Shown at 12 are a plurality of cooling-water injection nozzles, which are disposed on opposite sides or around the periphery of cracking tool P and arranged in several rows in vertically parallel relationship, in a manner that each row of injection nozzles may be individually operated independently of other rows, depending upon a thickness of the piece B. The plurality of injection nozzles may be arranged in a single row, in fashion that they are vertically moved for adjusting their heights, depending upon a thickness of the cracking piece.

In cracking operation, the adjusting plate activating hydraulic cylinder 9 is actuated under remote control to pivotally move the movable adjusting plate 6 upwardly until the upper surface thereof reaches the same level as the cracking-tool receiving member Q (the adjusting plate becomes inclined), from the stationary condition as shown by the solid line in FIG. 1, where the cracking tool P is in the upwardly retracted position. Then, the piece B is placed on the movable adjusting plate 6 and shifted to a position aligned with the center of the cracking tool P as well as cracking-tool receiving member Q, so as to determine a cracking point for the piece B. Subsequently, the hydraulic cyl inder C is actuated under a remote control to move the main shaft 1 downwards. The instant the point of cracking tool P mounted on the lower end of the main shaft 1 comes to contact the piece B, the adjusting plate 6 is moved downwards, so that the cracking piece B .placed thereon may be held in clamped condition between the cracking-tool receiving member Q and the cracking tool P. With the continuing downward movement of the main shaft 1, the pressure by the cracking tool P is exerted progressively on the peice B, whereby the point of cracking tool P is lodged in the piece B by cooperation of the cracking-tool receiving member Q.

. In the mid course that the cracking tool P is making access to the cracking-tool receiving member Q, there occurs an abrupt temperature rise in a press-and-slide portion A or gap defined along the lodged face on which portion the cracking tool is pressed. The instant the temperature-rise occurs, cooling water is injected from injection nozzles 12 into the press-and-slide portion or gap A, under the continuing pressure of the cracking tool P being exerted thereon. Thus, there will instantaneously result an amazingly strong cracking force of several times as high as the power posessed by the cracking apparatus itself, thereby faciliating the cracking operation.

Referring now in detail to the cracking action described, in conjunction with FIG. 3 illustrating respective step of cracking. FIG. 3 (a) shows a status of the cracking tool P, with its point being in contact with the piece B placed on the cracking-tool receiving member Q, immediately before the application of pressure thereto and the commencement of the cracking operation. FlG. 3(b) shows that the cracking tool P is forced downwards to lodge its point in the piece B by the cooperation of the cracking-tool receiving member Q until its point makes access to the cracking-tool receiving member Q for achieving cracking. In this situation,

the pressure of the cracking tool P acts as cracking load in the direction ofG, while it acts as a lodging load in the directions ofS. Meanwhile, in the press-and-slide portion A in the cracked face of piece B, on which portion the tapered point of cracking tool P is presed, the structure of grains is subjected to a change, presenting the compressed and extremely dense grain condition. This causes a grain-struggling phenomenon, resulting in the abrupt temperature rise from 200 to 350 (a first phenomenon). When the temperature rise has occured, if the downward movement of the cracking tool P proceeds at a proper timing for further exerting pressure on the cracking piece P, there is produced an extremely small gap (0.] to 0.5 mm) between the tapered periphery of the tip of cracking tool P and the lodged face in the piece B, due to reaction difference resulting from the oil pressures fed to respective portion of the hydraulic cylinder C (a second phenomenon). At that moment, cooling water is injected from the injection nozzles 12 arranged on opposite sides of the cracking tool into the press-and-slide portion or gap A, thereby quenching the press-and-slide portion A heated to elevated temperatures and a heated layer A, and thus the structure of grain therearound becomes embrittled (a third phenomenon).

Further, the cooling-water injection and the downward movement of the cracking tool P for exerting pressure on the piece B are re-started, whereby the piece B is cracked into pieces with ease shown in FIG. 3(c) (a fourth phenomenon).

It should be noted that operations of respective portions are adjusted in due time depending upon the mass of the piece B to be cracked, so that the first through fourth phenomena described may be instantaneously effected. In case any of the above-described phenomena is effected at a delayed timing, the increase in the cracking force will not be achieved. Thus, it is exremely important to adjust those phenomena so to occure in due time. For the purpose of adjusting timings, there are some cases where respective operation is repeated several times.

In the cracking operation described, the cooling water injected in the press-and-slide portion or gap A causes chemical reaction under the influence of elevated temperature in said portion, whereupon the evaporation and hence the expansion of the cooling water prevails in the lodged portion of the piece to be cracked whereby the heat-affected layer A of the piece B becomes hardened, as its grain structure remains out of balance, thus the piece B being embrittled. Such a phenomenon, in combination with the physical action such as the cracking operation due to the power possessed by the cracking apparatus, contributes to the improvement in the cracking performance.

Both the physical and chemical actions as described are concurrently caused, so as to instantaneously produce the cracking force of several times as high as the power possessed by the cracking apparatus, itself. Meant by the chemical actions are: (a) the change in the structure of particles constituting the piece B which change is caused due to the cracking tool being pressed for exerting pressure on the piece B (the cause of the temperature rise); (b) instantaneous evaporization of the cooling water and an energy producing phenomenon which is caused due to the production of static electricity; (c) a phenomenon of embrittling the structure of grains in high temperature area which is caused due to the abrupt cooling; and (d) the extremely lowtemperature gas (non-detrimental to a human being) is utilized to efficiently increase the cracking power obtained by the cooling water described in (b), so that the phenomenon of breaking the structure of the material to be cracked may be caused by the extremely large cracking power to be obtained through the genuine chemical action. Meant by the physical actions are: (a) a phenomenon of cracking a material under hydraulic pressure with the cracking force inherent to the cracking apparatus itself; (b) a phenomenon of temperature rise which is caused due to the cracking tool being pressed under pressure on the cracking piece; (c) a coolingwater instantaneous injection action; and (d) the concentrated arcing of the static electricity produced.

According to the apparatus for cracking castings of the present invention, the above-described chamical and physical actions are concurrently caused so as to provide an amazingly strong cracking force of several times as high as the power possessed by the cracking apparatus itself, and the cracking forces thus obtained are applied, in combination with the cracking force possessed by the cracking apparatus, for cracking a piece to be cracked. Thus, the cracking apparatus of the present invention may be used not only for the cracking and thus the reuse of castings or non-ferrous metals but also for the cutting of extremely thick plates. Further advantages are that the cracking operation is conducted for a short period of time irrespective of mass of a casting to be cracked, and in addition, the cutting may be conducted for a short period of time and at low cost even for extremely thick plates such as 500 mm or 600 mm thick. Besides the improvement in the cracking and cutting performances, the pressure to be exerted by the cracking apparatus itself on a material to be cracked may be saved to a considerable extent, yet the cracking apparatus is simple in construction. These contributes to providing an afficient cracking apparatus.

I claim:

1. An apparatus for cracking castings characterized in that; a piece to be cracked, placed on a crackingtool receiving member fixedly mounted on a bedplate is given a pressure progressively by a cracking tool, said cracking tool being located above said piece and adapted to be vertically moved by means of hydraulic pressure so as to lodge its point in said piece by the cooperation of said cracking-tool receiving member; and, when an abrupt temperaturerise occurs in a press-andslide portion on a lodged face in said piece on which portion the cracking tool is slidingly pressed, cooling

Claims

1. An apparatus for cracking castings characterized in that; a piece to be cracked, placed on a crackingtool receiving member fixedly mounted on a bedplate is given a pressure progressively by a cracking tool, said cracking tool being located above said piece and adapted to be vertically moved by means of hydraulic pressure so as to lodge its point in said piece by the cooperation of said cracking-tool receiving member; and, when an abrupt temperature rise occurs in a press-and-slide portion on a lodged face in said piece on which portion the cracking tool is slidingly pressed, cooling water is injected on to said pressand-slide portion, with the continuing downward motion of said cracking tool for exerting pressure thereon, whereby physical and chemical actions are concurrently caused, thereby instantaneously producing a cracking force of several times as high as a power possessed by said cracking tool itself.