US2942311A - Method and apparatus for stripping casting - Google Patents

Description

June 28, 1960 e. B. MEGINNIS METHOD AND APPARATUS FOR STRIPPING cAsTmc Filed Aug. Tea, 1957 I .6 A g F v \:/W.\/\!\M\//4 \\\\\.\\\-/W/.W R. W Y. L a W. m H 1 lll I: w A I A WW ,4 Mr A A 1!. A .A r A ll! M ill A. 2 d a. I. Z MW .6 fi W v, i 5 i f 2 A 2., I w 9 A v f- A III AW] I Z I, w! A .A II A I1 I! v 2 w a M MAT/lib United States METHOD AND APPARATUS FOR STRIPPING CASTING Filed Aug. 28, 1957, Ser. No. 680,799

4 Claims. (Cl. 22-1) The present invention relates to a method and apparatus for stripping a metal tube used in forming a cast object and which method and apparatus maximizes the material salvageable in the formation of such object.

In the process of forming a casting in which a steel tube or cup is used in conjunction with a material to which an additional material is to be bonded, it has heretofore been the practice after the casting has been completed to machine away thesteel tube or cup. In this process the rough casting including steel cup is non-concentric, none the less, a concentrically moving cutting tool is used to remove the cup which has resulted in scrap material in which the steel tubing cuttings are inextricably mixed with the metal thereadjacent in the casting with a resultant non-salvageable waste product. Further, the necessity for machining away the steel tubing has occasioned high machine tool wear further adding to the cost of the casting forming process.

In the present invention a method and apparatus have been devised in which it is possible to practically completely salvage the cast material as scrap and further in which no machining operation is necessary in separating the steel tubing from the remainder of the casting.

In the subject invention the steel cup or tube is reverse drawn relative to the casting which turns the cup inside out and in so doing mechanically separates the tubing from the casting in such a way that very little casting material adheres to the tubing. Further, when the tubing or cup is practically completely inverted the tube is sheared off from the remainder of the casting which may thereafter be finished to size.

It is also an object of the present invention to provide a punch and die apparatus in which the expendable steel cup is automatically stripped from the punch after the tube has been sheared and further in which the casting is stripped from the punch when the latter is withdrawn from the die. v

The details as well as other objects and advantages of the present invention will be apparent from a perusal of the description which follows.

In the drawings:

Figure l is a partially sectioned view of the subject apparatus; V

Figure 2 is a fragmentary partial section of the apparatus prior to the stripping of the tube from the casting; and

Figure 3 is a partially sectioned view of the apparatus just prior to the completion of the stripping operation.

A punch press is shown generally at in Figure 1 and save as will be particularly described and claimed constitutes no part of the present invention. Press 10 includes a punch member 12 suitably mounted therein and adapted to be moved downwardly to cooperate, in the manner to be described, with a die 14.

, A typical cast member with which the subject apparatus may be employed is shown generally at 16. The casting 16 in this instance, includes a steel backing member 18 on which a bronze face 20 is adapted to be cast.

atent O F 2,942,311 Patented June 28, "1960 To cast the bronze face 20 onto member 18, a steel tube or cup-shaped member 22 having a flange 24 at its lower end is welded into a recess 26 formed in one end of the backing member. In this way an annular space is formed between member 18 and cup 22 and into which space molten bronze is poured. The bronze thereafter forms an alloy bond with back member 18. It is to be understood that the particular metals noted are merely for illustrative purposes and the present apparatus and method may be utilized with any casting in which it is'desired to remove an expendable and non-frangible core member therefrom.

After the casting is poured and has solidified it is mounted on the die 14 and more particularly on the shear ring 28.

The punch 12 includes a main shank portion 30 which terminates in a tapered end section 32. End section 32 includes a recess 34 formed therein and adapted to s1idably receive a piston or ejector member 36. The piston member 36 is suitably recessed and bored at 38 to permit a stud 40 to pass therethrough and be threaded into a threaded bore 42 in the tapered section 32 to prevent the ejector piston 36 from becoming detached from the punch 12. A plurality of such studs may be employed if necessary.

A plurality of matching recesses 44 and 46 are formed in the tapered section 32 and piston 36 and are adapted to receive therewithin compression spring members 48. For reasons to be described, the spring members 48 are adapted to bias piston member 36 in an extended position relative to the tapered section 32. Punch 12 is formed in a way to provide a shearing collar 50 disposed intermediate sections 30 and 32 thereof.

As best seen in Figure 3, as the punch 12 is moved downwardly, the piston 36 engages cup-shaped member 22 and in so doing the piston is moved axially into the punch recess 34, as seen in Figure 3. The continued downward movement of punch 12 will cause the steel cup or tube member. to be turned inside out and stripped away from the material 20 previously cast to the backing member 18. In thus reversely drawing or inverting the tube 22 very little of the material 20 will adhere thereto.

When the cup or tube 22 is completely inverted the shearing collar 50 approaches the shearing ring 22 of die '14 and continued movement will cause the cup to be sheared ofi along flange 24. Due to the tapered form of punch section 32 and the strength of spring members 48, the ejector member 36 will cause the sheared tube 22 to be stripped from punch section 32.

A ring 52 is suitably fixed to the punch shank 30 for movement therewith. A corresponding ring 54 is mounted on the punch shank 30 but is adapted to slide axially with respect thereto. Slidable ring 54 is normally axially spaced from fixed ring 52 and connected thereto through a plurality of circumferentially spaced spring elements 56. It is intended to provide means such as studs, not shown, loosely connected between rings 52 and 54 to prevent the rings from separating beyond that amount indicated in Figure 2. Y

The purpose of the ring members 52 and 54 is to insure that the casting 16 will be stripped from the punch 12 when the latter is withdrawn from the die 14. Thus, as will be best seen in Figure 3, as the shearing collar 50 approaches the shear ring 28, the movable ring 54 will engage the upper end of the casting member 16. As the punch continues its downward movement the ring 52 will be moved axially toward the movable ring 54 and in so doing will compress the spring members 56. As the punch 12 is withdrawn from the die 14 at the end of the shearing operation, the spring members 56 will cause the movable ring 54 to exert an appreciable axial force against the casting and in so doing insure that the latter will not adhere to the punch when the latter is Withdrawn preliminary to starting another stripping operation.

Thus the punch 12 includes a pair of stripping devices, piston 36 and rings 52 and 54, which are adapted respectively to strip the expended tube 22 from the tapered section 32 of the punch and also to strip the casting, per se, from the shearing collar 51L As seen in Figure 1, an open trap or chute 58 is formed below the die member 14 in the bed of'punch press in order that the expended caps 22 may be ejected from the front of the press and thereby not inhibit the continuous operation of the subject apparatus.

It is apparent that various structural modifications may be made in the subject apparatus within the scope of the inventive concept hereinabove set forth.

I claim:

1. An apparatus for removing a cup shaped liner from a hollow cast member bonded thereto comprising a die adapted to support said member with the open cup end adjacent the die, a punch,- piston means slidably mounted in the punch, means biasing said piston means axially away from the punch, said piston means being adapted to engage said cup during the movement of said punch toward said die whereby the piston means is moved into axially abutting relation with said punch, a shearing collar disposed on said punch intermediate the ends thereof, said collar being adapted to engage with and shear off said liner after said punch has inverted and mechanically separated the liner from said member, said biasing means being adapted to move said piston means to strip said liner from the punch after shearing, and means adapted to strip said member from said punch when the latter is withdrawn from said die.

2. An apparatus as defined in claim 1 in which said member stripping means comprises a first collar fixed to said punch, a second collar slidably supported on said punch, said collars being disposed on said punch anteriorly of shearing collar, and means for resiliently connecting said first and second collars in axially spaced relation.

3. An apparatus for removing a cup shaped liner from a cast member comprising a die adapted to support said member with the open cup end adjacent the die, a punch means adapted to engage the closed end of said cup and invert the latter in moving toward said die, a shearing collar disposed on said punch means intermediate. the ends thereof, said collar being adapted to shear off said liner after said punch means has inverted and mechanically separated the liner from said member, means for stripping said sheared cup from said punch means, and additional means adapted to strip said member from said shearing collar when the punch means is withdrawn from said die. 7

4. An apparatus as defined in claim 3 in which said punch means includes a tapered end section for coacting with said liner, and further in which said sheared cup stripping means is disposed in a recess formed in said tapered end section and comprises a piston slidably supported within the recess for axial movement relative to the punch, spring means biasing said piston axially away from said punch, and stop means for limiting the axially away movement of the piston.

References Cited in the file of this patent UNITED STATES PATENTS 1,393,195 Bradley Oct. 11, 1921 1,630,715 Nice May 31, 1927 2,031,982 Salzman Feb. 25, 1936 2,330,762 Tooker Sept. 28, 1943 2,422,952 Dakin June 24, 1947 2,730,763 Brundage Jan. 17, 1956 2,796,634 Chellis June 25, 1957

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