US3012295A - Molding apparatus - Google Patents

Description

3 Sheets-Sheet 1 Filed April 15, 1959 INVENTOR. ROBERT LAPSLEY ATTORNEY.

Dec. 12, 1961 R. LAPSLEY 3,012,295

MOLDING APPARATUS Filed April 15, 1959 3 Sheets-Sheet 2 INVENTOR. ROBERT LAPSLEY W ZZZ/4,56

ATTORNEY Dec. 12, 1961 R LAPSLEY MOLDING APPARATUS Filed April 15, 1959 3 Sheets-Sheet 3 FIG. 6

INVENTOR. ROBERT LAPSLEY Wzdzf ATTORNEY United States Patent Ofilice 3,012,295 Patented Dec. 12, 1961 3,012,295 MOLDING APPARATUS Robert Lapsley, Berrien Springs, Mich., assignor to Clark Equipment Company, a corporation of Michigan Filed Apr. 15, 1959, Ser. No. 806,689

2 Claims. (CI. 22-13) The present invention relates to apparatus for molding complex which may be used in the casting of certain forms having irregular or oddly positioned portions.

Bladed or vaned rotor wheels such as are employed in hydrodynamic torque converters have been difficult to form in a single casting by the use of prior methods because of the complex contour of the vanes. Ordinarily, the vanes on such wheels are supported either on a hub or a rim, or in some cases, between a hub and a rim. In casting the complete wheel, one or more core members having cavities therein conforming to the desired vane configurations are employed and the hub and rim or, in some cases, one or the other, are cast integrally with the vanes. A principal dilficulty which has previously been encountered in using this method of casting bladed wheels has been the initial formation of the core. In accordance with one prior art technique, multiple part cores are employed, but such cores are difiicult to assemble and, in addition, the finished product is characterized by the presence of a large number of burrs or projections, commonly called flash, which must subsequently be removed. Accordingly, a one-piece core is preferable.

In accordance with one prior art method of making a one-piece core for the vanes of rotor wheels, there is employed a heat disposable pattern which is melted and removed from the core in a liquid state after the core has been hardened. Since the pattern cannot be re-used, the production cost is relatively high. In accordance with another prior art technique, the vanes are specially designed to permit unscrewing of the pattern from the casting in a die-casting process. However, it is preferable to design the vanes for optimum performance rather than for simplicity of manufacture. Accordingly, both of these methods of making bladed rotor wheels leave much to be desired.

An object of the present invention is to provide a new and improved apparatus comprising a core box for molding a one-piece core having irregular or oddly positioned portions.

A further object of the present invention is to provide a new and improved core box for molding a one-piece core which may be utilized to form the vanes in a cast rotor wheel.

A still further object of the present invention is to provide a new and improved apparatus for molding a one-piece core for a vaned element wherein the vane patterns are separate elements which are removed from the core in a radial direction.

Briefly, the above and further objects are realized, in accordance with the present invention, by providing an apparatus using a multi-piece core box having a plurality of removable core box elements cooperating to form a one-piece core. The core box generally comprises a removable outer annular pattern member supported upon a base plate which has an upstanding inner annular pattern portion formed integrally therewith and concentric with the outer annular pattern member. A removable inner annular pattern member is supported in upstanding position upon the inner annular pattern portion and cooperates therewith to form a locating means and support for the inner ends of a plurality of removable vane pattern elements which are disposed radially in the annular space between the inner and outer annular pattern portions. The outer pattern member also provides a locating and supporting means for the radially outer ends of the removable vane pattern elements. The removable vane pattern elements conform precisely to the form of the vanes which it is desired to cast and are removable from the core in a generally radial direction after the core has become partially hardened so as to be self-supporting.

Although the present invention is particularly suited for use in the molding of cores for casting bladed or vaned rotor wheels, it will be readily apparent to those skilled in the art that by a proper selection and arrangement of the removable core box elements, cores for many complex configurations may be readily molded in a single piece.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following description and claims, taken in conjunction with the accompanying drawings in which: 7

FIGURE 1 is an isometric view of a bladed or vane rotor wheel typifying a casting that is made possible by using a core made by the present invention;

FIGURE 2 is fragmentary elevational view, partly in section, that is, with the outer rim of the wheel of FIG. 1 cut away, illustrating the general configuration of the vanes;

FIGURE 3 is an isometric view of a finished one-piece core for molding a vaned wheel, which may be produced in accordance with the present invention;

FIGURE 4 is a fragmentary cross-sectional view through a mold for casting a vaned rotor showing a core made by utilizing this invention in place;

FIGURE 5 is a top plan view, partly in section, of the assembled core making apparatus of the present invention;

FIGURE 6 is a cross-sectional view of the assembled core making apparatus substantially as seen along the line 6-6 of FIG. 5; and

FIGURE 7 is a fragmentary top plan view, partly in section, of a portion of the core making apparatus illustrating the manner in which the vane pattern elements are removed from a core in accordance with the present invention. 7

Referring to the drawings, and particularly to FIGURE 1 thereof, there is illustrated a bladed or vaned rotor generally designated by the reference numeral 10 which comprises a pair of concentric annular portions 12 and 14 and a plurality of circumferentially spaced vanes 16 in- -terposed between and cast integrally with the annular portions. As previously mentioned, such a rotor may, for example, be utilized in a hydrodynamic torque converter.

A rotor of the type herein shown may be utilized as a reaction element in such a torque converter for redirecting the working fluid from a turbine to a pump. It is desirable in such rotors that the blades be of a configuration which produces a smooth oil flow within the converter and thereby provides maximum power, by incorporating the correct combination of blade contours and blade angles, which are major factors in achieving the highest possible elliciency. Such blade shapes are illustrated in FIGURE 2 of the drawings herein. As may be seen, the vanes 16 are generally fish shaped and have a twisted form; that is, the shape of each of the vanes 16 is essentially the same as would be achieved by twisting the outer leading edge of the vane about the trailing edge while holding the inner edge adjacent the annular portion 14 fixed. The vanes 16 also are tapered or of varying thickness which decreases from the radial inner to the radial outer portions thereof.

In the past the problem of removing a pattern of a vane having such a shape has prevented the manufacture of a rotor core having provision for twisted blades or vanes by casting in a single integral part. It is the purpose of the present invention to provide a new apparament comprises a circular base plate 2 8 having formed integrally therewith an upstanding inner annular pattern portion 30; a removable inner annular pattern member 32' which is adapted and arranged tobe mounted upon the pattern portion 30 and generally forms a vertical continuation thereof; a removable two-piece outer annular pattern member 34; and a plurality of circumferentially spaced removable vane pattern elements-36. The base plate 28 is provided witha shouldered flange 38 about its periphery which forms a support for the patternmemiber 34 and both the base plate 28 and the pattern member 34 are provided with a pair of cooperating diametrically opposed radially outwardly projecting lugs 40 and 42 respectively. Extending upwardly from each of the lugs 40 is anadjustable screw post 44 which is adapted and arranged to pass through an enlarged aperture 46, in the lugs 42 and together with a pivotally mounted cam member 48 and removable spacer element 50 provide an adjustable and rapid means of assembling thumb screws 88 or the like for a purpose to be developed more fully hereinafter.

As previously mentioned, the outer annular removable pattern member 34 is of two-piece construction. This construction provides a split ring type of assembly which may be assembled and disassembled by means of quickconnect cam type clamp elements 90 similar to those previously described.

Having now described in detail the structure of the various elements which cooperate to produce the improved core molding apparatus of 'the present invention,

' it is believed that a better understanding thereof may be had by describing the method of using such apparatus to mold a one-piece core such as the core 18 shown in FIG. 3. Accordingly, in order to employ the apparatus of the present invention the surfaces of the various pattern elements are first thoroughly cleaned and oiled and then assembled in the following manner. The two-piece outer annular pattern member 34 is first assembled and and disassembling the base plate 28 and pattern member 34 relative to one another. In addition, each of the lugs 42 is provided with a tthreadably received thumb screw 52 or the like which when turned down engages the lugs 40 andservesas a means to initially force the element 34 upwardly from the base plate 28 to separate them in the event they should stick together after a molding operation.

Extending radially inwardly from the flange 38 of the base plate 28 is an annular fiat surface 54 which forms a base for the core 18 and to whichis connected the upstanding inner annular pattern portion 30. The pattern portion is provided with a horizontally extendingvsupport wall 56 across the top which has connected at the center thereof an upstanding screw post 58 which is adapted and arranged to pass through an enlarged aperture 60 in the base portion 62 of the removable pattern member '32. The screw post 5-8 is provided with a pivotally mounted cam member 64 and a removable spacer member 66 which cooperate to form a quick disconnect clamp means for securing the member 32 to theportion 30. The pattern member 32 is also provided with a pair of diametrically opposed thumb screws 68 '(see FIG. 5) -or the like which when turned down engage the support wall 56 and serve as a means to initially separate the member 32 from the portion 30 afiter a molding operation. Alignment of the parts 30 and 32 is secured by means of a suitable locating pin 70 which may be secured to one of the elements such as the element. 3!) and passes through an aperture 72 in the other of the elements.

Each of the pattern parts 3! and 32 is provided with a plurality of circumferentiaily spaced, generally radially disposed grooves 74 which are semi-circular in cross section and are adapted and arranged toregistcr with one another and to receive locating pins 76 which are afiixed to the radially inner ends of each of the vane pattern 3 elements 36.' The outer pattern member 34 is provided with 'two axially spaced sets of circuinferentially spaced,

radially disposed drilled apertures 78 and 8'8 which are adapted and arranged to receive locating pins 82 and 84 afiixed to the radially outer end; of each of the vane pattern elements 3 6. The apertures of one set such as 80 communicate with concentric enlarged threaded apertures 86 which are adapted and arranged to receive the removable vane pattern elements 36 are then assembled thereto by insertingthe locating pins 82 and84 in their respective apertures .78 and 80. This sub-assembly is then placed upon the base plate 28 whereupon the locating pin 76iwill be received within the semi-circular grooves 74 in the pattern portion 30. The pattern member 32 is then placed and clamped in position upon the pattern 'element-30 to provide the complete assembly as-shown in FIGS. 5 and 6.. The locating pins and clamp suitable core material. "Afterall of the voids in the pattern apparatusdiave been filled, the core material is permitted to harden and, if desired, this hardening may be accelerated by applying heat to the apparatus. When \the core material has become firm enough to maintain its shape without the support of the various pattern elements of the apparatus, the inne'r'annular removable pattern member 32 is removed by lifting same axially away from the molded core, after cam member 64 has been moved to a vertically disposed position. If necessary, the thumb screws 68 may be utilized to effect an initial separation of the pattern member .32 from the molded core as previously mentioned. The combination comprising the outer annular pattern member 34, the vane pattern elements 36, and the molded core, are then lifted axially up away from'the base plate 28. The vane pattern elements 36 are then removed'from the molded core by radial inward movement into the space vacated by the inner annular pattern portions '30 and 32. In order to etfect removal of the vane pattern elements 36 from the molded core, thethumb screws 88 are rotated and screwed radially inwardly to contact the locating pins 84 to initially break any bond and separate the vane pattern elements 36 from the molded core. The vane pattern elements 36 may then be removed one at a time in sequence circumferentially by pulling them radially inwardly. Since, as previously mentioned, the vane pattern elements 36 are tapered so that they are thinner at their radially outer ends, the radial inward movement thereof does not disturb the molded core. As soon as the radially outer locating pins 82 and 84 are free of their respective apertures 73 and in'the *pattern member'34, the vane pattern elements 36 are the molded core. The two-piece outer annular pattern member 34 is then disassembled and removed from the molded core and a core such as that shown in FIG. 3 results. f necessary, any thin fins or flash which may project from the molded surfaces as a result of the narrow cracks between the various pattern elements of the apparatus may be smoothed off before using the core in a casting operation.

There is thus provided in accordance with the present invention method and apparatus which may be used in a simple and inexpensive manner to form a one-piece molded core for use in the casting of vaned rotor wheels having vanes of twisted form. A similar method and/or apparatus may be used in the casting of many other articles having relatively complex surfaces of curvature. For example, if it were desired to produce a molded core for a vaned element wherein the vanes had draft angles such that the vane pattern elements would have to be removed by radially outward movement, it is obvious that the outer annular pattern member might be readily modified to permit of its removal as a first step in the disassembly of the apparatus whereupon the vane pattern elements could then be removed from the molded core by exerting a radially outward force thereon.

While the present invention has been described herein by way of reference to but one specific illustrative embodiment thereof, it should be apparent to those skilled in the art that numerous other embodiments, modifications, alternations, and substitutions of equivalents are possible without departing from the true spirit and scope thereof. For example, certain steps in the assembly and disassembly of the core making apparatus may be effected by automatic means or machinery in a manner well-known in the art, which means or machinery could be readily substituted for the quick-connect clamp devices and thumb screw elements described herein. Another example relates to the material of the individual pattern elements 36. These may be of metal in many instances, although in some cases it is beneficial to make them of rubber or other resilient material to facilitate their removal after the core has hardened suificiently. It is, therefore, not intended that the present invention should be limited to the specific embodiment illustrated and described; nor otherwise than by the terms of the appended claims.

What is claimed as new and desired to be secured by Latters Patent of the United States is:

l. A molding apparatus for molding a one-piece core comprising a base member, an upstanding stationary annular pattern portion supported on the said base mem her, a firs-t removable annular pattern member adapted and arranged to be supported upon said stationary pattern portion, a second removable annular pattern member adapted and arranged to be supported upon said base member radially outwardly from said first removable annular pattern member and in concentric relationship with the first removable annular pattern member to form an annulus therebetween, a plurality of removable vane pattern elements adapted and arranged to be supported in the annulus for withdrawal inwardly in a generally radial direction in part at least through the space normally occupied by said first removable pattern member, and locating pins on the radially inner ends of said vane pattern elements at least one locating pin on each such element, the said upstanding pattern portion and said first removable pattern member having grooves in the abutting surfaces thereof jointly forming recesses for receiving all of the said locating pins.

2. A pattern fixture for molding a one piece core for use in casing a one-piece rotor wheel which includes a plurality of curved vanes comprising, a base member, a first upstanding annular pattern portion integral with the said base member, a second annular pattern portion adapted to be removably mounted upon said first annular pattern portion, a third annular two part pattern portion adapted to be removably mounted upon said base member radially outwardly of and in concentric relationship to said first and second annular pattern elements forming an annulus therebetween, a plurality of vane pattern elements adapted to be supported in radial arrangement in the said annulus, locating pins on the radially inner and outer ends of said vane pattern elements, said first and second annular pattern portions having grooves in register in the abutting surfaces thereof jointly forming recesses for receiving the said locating pins on the inner ends of said vane pattern elements for supponting such inner ends, said third annular pattern portion having recesses formed therein for receiving the said locating pins on the outer ends of said vane pattern elements for supporting such outer ends, and means on said third annular pattern portion adapted to engage the said locating pins on the outer ends of said vane pattern elements to initiate movement of the said vane pattern elements radially inwardly after the said annulus has been filled with mold material and following disassembly of the said first and second annular pattern portions, the said vane pattern elements being removable through the space previous-1y occupied by the said first and second annular pattern portions.

References Cited in the file of this patent UNITED STATES PATENTS 1,561,811 Wheller Nov. 17, 1925 2,301,140 Pfeiffer Nov. '3, 1942 2,510,735 Bodger June 1, 1950 2,611,161 Paul et a1 Sept. 23, 1952 2,702,418 Miner Feb. 22, 1955 2,782,477 Bean et al. Feb. 26, 1957 2,887,744 Halliday May 26, '1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N00 3 O12,2 95 December l2 1.961

Robert Lapsley ertified that error appears in the above numbered patd Letters Patent should read as It is hereby c ction and that the sai ent requiring corre corrected below.

after czomplex insert cores 'o Column 1, line 9,,

Signed and sealed this 31st day of Jul (SEAL) Attest: ERNEST w. SWIDER V D L D Commissioner of Patents Attesting Officer

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