Casting Handling Apparatus

The present invention relates to the field of foundry casting and more particularly to the handling of hot foundry castings while such castings are removed from the associated molds. In even greater particularity the present invention relates to sand casting such as utilized in lost foam sand casting. More particularly the present invention relates to the segregation of the casting and sand and transportation of the casting for further processing.

It is well known in the art that hot castings, particularly aluminum are susceptible to handling damage upon exiting the mold and for a period of time thereafter. Thus compressing forces and impacting forces must be avoided to insure that a high percentage of the foundry castings remain unblemished by handling.

It is the object of the present invention to provide a system for receiving a hot casting and sand mold, segregating the casting from the mold and transporting the casting for further processing with minimal damage to the casting due to handling.

It is a further object of the invention to provide such a system which is capable of handling a continuous series of castings as they are discharged from a continuously operating foundry casting system.

Yet another object of the invention is to provide additional cooling to the casting while the casting is being transported.

Apparatus embodying features of my invention are depicted in the accompanying drawings which form a portion of this disclosure and wherein:

FIG. 1 is a plan view of a tandem casting handling apparatus in accordance with my invention;

FIG. 2 is a sectional view of FIG. 1 indicated by line 2--2 showing a dump station in a lost foam casting system and my handling system adjacent thereto for receiving the castings and molds discharged thereby.

FlG. 3 is a side elevational view of a quenching tank including a walking beam conveyor;

FlG. 4 is a sectional view taken along the longitudinal axis of the tank in FlGS. 3; and

FlG. 5 is a perspective view of my basket and turntable assembly.

Referring to the drawings for a clearer understanding of my invention it will be appreciated that this apparatus is designed for use in conjunction with a sand mold casting system such as described in U.S. Pat. No. 4,736,787 owned by the common assignee herewith. In FIG. 1, such a casting system is depicted at 11 and has a pair of tandem dump stations 12 which remove the sand and casting from the casting system 11 to my handling apparatus depicted generally at 13. My apparatus 13 includes a receiving station 16 for each dump station. Each receiving station includes a support 17 for receiving sand from the dump station 12. In the embodiment shown the support 17 is a vibrating screen type conveyor which is conventional in the industry, and which moves the sand to a bin 14 from where it can be recirculated to the casting system 11. It will be appreciated that a dump table might also serve as support 17, in as much as the primary function of the support 17 is to accumulate the sand as it is dumped to cushion the landing of the enclosed casting and then to remove the sand for recirculation. It is noteworthy to mention that It Is the accumulation of sand which prevents damage to the casting; thus a sufficient depth of sand must be accumulated on support 17 to cover the lower portion of a basket 18 into which the sand and casting are deposited.

Preferably the basket 18 is made of a plurality of parallel structural members 19 (see FIGS. 2 and 5) which have a first portion 21 extending horizontally and a second portion 22 extending vertically. The structural members 19 are connected to each other by spacer bars 23 and a number of members 19 on the side of the basket 18 away from the dump station 12 have an upper portion 24 which extends upwardly and are connected to a turntable beam 26. As can be seen the baskets 18 are open on three sides and sand can readily pass between the structural members 19.

Beam 26 supports the basket 18 and an identical basket 18' at its opposite ends. The beam 26 and baskets 18, 18' are mounted to a turntable-like assembly including a disk-like plate 27 supported on an annular rail 28 which in turn rests on several casters 29 which are mounted for rotation about horizontal axis in brackets 30 attached to a support member 31 which forms a cross. At the center of the support member 31 is a drive unit 32, which may be a hydraulic motor, or hydraulic rotary actuator, which has a vertical output shaft 33 affixed to the underside of plate 27.

The support member 31 is affixed to the top of a vertical ram 34 or hydraulic actuator which can be extended to lift the beam 26 to a height such that the lower portion of the baskets 18, 18' are above the height of the sidewalls of the sand support members 17, and above the height of the sidewalls 35 of a quenching tank 36.

The quenching tank 36 has end walls 37 and a bottom 38 in watertight contact with the sidewalls 35 and a pair of watertight sleeves 39 extend across the tank and through the sidewalls 35. Each sleeve 39 has a drive shaft 41 extending therethrough and mounted in bearings 42 at each end of the sleeve 39. Each drive shaft 41 is in turn driven by a suitable motor 40, which may be electric or hydraulic, connected thereto by a belt or chain 43. Each end of each shaft 41 carries an aligned crank arm 44 which supports at the outer end thereof a vertical frame member 46, such that four such frame members are supported in matched pairs on each side of the quenching tank 36 at the ends of the drive shafts 41. Each frame member 46 has an upper and lower portion 46a & 46b respectively which are connected by bolts 47 passing through selected apertures 48 in their mating ends as shown in FIG. 3. Each vertical frame member 46 is attached at the upper end of portion 46a to each adjacent vertical frame member 46 by a lateral spanning member 51, outside the quenching tank 36 and a cross member 52 which extends over the quenching tank 36, with each attachment secured by appropriate braces such as at 53.

Depending from the cross member 52 and inwardly of the sidewalls 35 are four vertical stringers 56 which support at their lower ends a pair of horizontal stringers 57 which extend longitudinally within the quenching tank 36. The horizontal stringers 57 in turn support a plurality of transverse stringers 58 therebetween Each transverse stringer 58 supports a plurality of upright supports 59 which are aligned beneath and support a plurality of longitudinally extending beam members 61 which serve as "walking beams". It will be noted that stringers 56 are of such length that the longitudinal and transverse stringers 57 and 58 are supported above the sleeves 39. The sleeves 39 and additional supports 62 support a plurality of fixed beams 63 on a plurality of stanchions 64, with the fixed beams 63 lying intermediate the walking beams 61 and being somewhat shorter in length. It will be appreciated that rotation of the drive shafts 41 causes a circular motion of the walking beam 61 in the vertical plane such that at the top of thIs circular motion the walking beams 61 rise above the tops of the fixed beams 63. The extent to which the walking beam 61 is above the fixed beam 63 during each rotation can be varied by varying the length of vertical support 46 or vertical stringers 56.

It should be noted that the spacing between the lower portions 21 of structural members 19 of the basket 18 is the same as the spacing between the fixed beams 63 and that when the basket 18 is in its lowermost position in the quenching tank 36 the lower portion 21 and beams 63 are aligned such that the walking beams 61 interstitially engage the lower portions 21. As can be seen in FlG. 1, a basket assembly can be placed at each end of the quenching tank 36 to cooperate with the walking beam conveyor to transport the castings.

In operation, it can be seen that the dump station 12 will lift a flask 66 containing a sand mold and casting from a gondola 67 of the associated foundry casting system 11 and will empty the contents onto the basket 18 which is positioned on the receiving support 17. The sand from within the flask 66 pours from the flask before the casting is discharged in sufficient quantity to cover the lower portion 21 of the basket 18 and thus cushions the impact of the casting dropping into the basket 18. The mechanical actuation of this step is obviously controlled to prevent operation of the dumping station 12 in the absence of a basket 18 and such control can readily be accomplished using limit switches or proximity switches (not shown) which detect the proper placement of the various components and enable the operation of the moving components. When the dump station 12 has deposited the sand and casting into the basket 18 and has retracted to replace the flask 66 on the gondola 67, the vertical ram 34 is actuated to raise the basket 18 above the sidewalls of the receiving station 17. Again, proximity sensors and limit switches may be used to detect compIetion of thIs function and enable further operation of the apparatus. As the basket 18 is raised the sand accumulated thereon passes between the structural members 19 and remains on the receiving support 17 from which it is mechanically removed by vibration or tilting or in any other suitable manner. Drive unit 32 is energized to rotate the turntable assembly through 180.degree. to reverse the position of baskets 18 and 18'. If desirable sprayer units (not shown) may be provided to rinse any remaining sand from the castings as they are carried by the basket 18 from the receiving station 17. A set of limit switches 69 may be mounted beneath the turntable assembly to control the rotation of the assembly such that the baskets 18 & 18' are moved almost precisely 180.degree. by the drive unit. When the rotation has been completed, ram 34 is utilized to lower the turntable such that basket 18' is placed in the receiving station 17 and basket 18 is lowered into alignment with the fixed beams 63. In the embodiment shown, fixed beam 63 is inside a quenching tank 36, which contains a level of quenching liquid, although castings of different metals may require different treatment such that a quenching tank may not be used. The moving beam 61 follows its circular path through the interstices between lower portions 21 and thus rises beneath the casting and urges it toward the stationary beam 63. After several revolutions of the walking beam, depending on the arc which is subtended by the stationary beam 63 and lower portion 21, the casting will be supported on the stationary beam 63 rather than the basket 18. While removal of the casting to stationary beam 63 is occurring, dump station 12 is depositing another casting into basket 18'. When the first casting is removed from basket 18 and a fresh casting deposited into basket 18:, the apparatus translates the baskets to their original positions. The cycle is repeated constantly with the castings proceeding along the walking beam conveyor to a second rotary transporter 71 identical to the one hereinabove described which removes the castings from the walking beam conveyor to another conveyor for processing. It should be noted that the use of rotary transporters at each end of the walking beam greatly facilitates the automation of the quenching tank 36.

From the foregoing it may be seen that the castings are transported from the mold through the quenching tank with minimal impact. It will be appreciated that the rotation of the drive shaft 41 can be controlled and the height of the rise of the walking beam 61 can be controlled, thus, the castings can be moved very gently, yet efficiently through the quenching tank 36. Accordingly, my apparatus greatly improves the quality of the finished product and diminishes the number of castings which must be discarded.

While I have shown my invention in one form, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the spirit thereof.