US20090000757A1

US20090000757A1 - Core-package handler and method

Info

Publication number: US20090000757A1
Application number: US11/768,415
Authority: US
Inventors: Christopher J. Colon
Original assignee: International Engine Intellectual Property Co LLC
Current assignee: International Engine Intellectual Property Co LLC
Priority date: 2007-06-26
Filing date: 2007-06-26
Publication date: 2009-01-01
Also published as: MX2008008300A; JP2009006398A; KR20080114557A; BRPI0803870A2; CN101337262A; EP2008738A1; CA2632808A1

Abstract

A plurality of grippers (502) is connected to a frame (800) of a machine (504). Each gripper (502) includes a drive portion (704) that includes a driven gear (712), a shaft portion (506) that is connected to the drive portion (704) and has an elongate shape with a centerline, and a head portion (508) that is connected to an end of the shaft portion (506) that is opposite the drive portion (704). The head portion (508) extends past an outer dimension of the shaft portion (506). At least one actuator (718) is connected to at least one drive shaft (716) that includes at least one driver gear (714). The driver gear (714) is meshed with the driven gear (712) of the gripper (504) such that a motion of the actuator (718) is transferred in turn to the drive shaft (716), to the driver gear (714), to the driven gear (712), and finally to the gripper (504) such that the gripper (504) rotates about the centerline.

Description

FIELD OF THE INVENTION

This invention relates to casting apparatus and processes, including but not limited to core-package handling methods and apparatus.

BACKGROUND OF THE INVENTION

Internal combustion engines include crankcases having a plurality of cylinders. The cylinders contain pistons whose reciprocating motion due to combustion events may be transferred through a crankshaft to yield a torque output of the engine. Often, engine crankcases are made of cast metal, and include passages integrally formed therein for the transfer of various fluids from one location of the engine to another. Fluids typically transferred through passages in an engine include coolant, air, fuel, oil, and so forth.
Known methods of manufacturing engine components include casting the components out of metal. A typical engine component is cast having one or more internal passages formed therein, and is then typically finished using various machining operations. Cast components are formed, typically, by pouring molten metal into a mold. The mold has an internal surface that forms a desired external shape of a part when the molten metal solidifies. Internal features are usually formed by cores, typically substantially made of sand or another suitable material, that are placed into the mold prior to pouring the molten metal.
Typical cores include one or more interlocking portions that are assembled into a core-package. The core-package is placed into a mold-half in what will be the internal cavity of the finished mold assembly. Handling the core-package for placement into the mold half is a delicate operation, primarily due to the brittleness of the core-package.
In a typical manufacturing setting, a single mold may form more than one internal cavity for casting multiple engine components per metal pouring operation. This means that a single mold may receive multiple core-packages before the pouring operation is performed. Often, core-packages are damaged during placement into the mold, yielding relatively high rates of material to be scrapped. This and other issues may be avoided as follows.

SUMMARY OF THE INVENTION

A plurality of grippers is connected to a frame of a machine. Each gripper includes a drive portion that includes a driven gear, a shaft portion that is connected to the drive portion and has an elongate shape with a centerline, and a head portion that is connected to an end of the shaft portion that is opposite the drive portion. The head portion extends past an outer dimension of the shaft portion. At least one actuator is connected to at least one drive shaft through at least one linkage that includes at least one driver gear. The at least one driver gear is meshed with the driven gear of the gripper such that a motion of the actuator is transferred in turn to the drive shaft, to the driver gear, to the driven gear, and finally to the gripper such that the gripper to rotates about the centerline.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an outline view of a mold half having three core-packages disposed therein.

FIG. 2 is a cross-section view of a set of known grippers engaging a core-package.

FIG. 3 is an outline view of a known core-package having recesses.

FIG. 4 is an outline view of an improved core-package having shallower recesses in accordance with the invention.

FIG. 5 and FIG. 6 are cross-section views of a gripper while engaging and disengaging a core-package in accordance with the invention.

FIG. 7 is an exploded outline view of a drive mechanism for a gripper in accordance with the invention.

FIG. 8 is an outline view of a machine that is arranged to engage multiple core-packages using grippers in accordance with the invention.

FIG. 9 is a flowchart for a method of handling core-packages with a machine in accordance with the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT

The following describes an apparatus for and method of handling core-packages for placement into mold cavities for casting of metal components having internal passages. A known core-package handling apparatus is shown in FIG. 1 through FIG. 3 for comparison.
A mold-half 100 that is part of a partially assembled mold assembly (not shown) is presented in FIG. 1. The mold-half 100 is shown containing three core-packages 102 placed within a cavity 104 of the mold half 100. The mold-half 100 is a lower half of a mold assembly. An upper half of the mold assembly (not shown) is typically placed over the mold-half 100 to complete and seal the cavity 104 around the core-packages 102 in preparation for casting. When the mold assembly is assembled, molten metal is poured through a mouth cavity 106 that is formed in the mold-half 100. The liquid metal that fills the mouth cavity 106 flows through a feed passage 108, past a slag filter 110, and into the cavity 104 to surround the mold-packages 102 and fill the cavity 104.
A plurality of wells 112 are formed in the mold-half 100 between and around each of the core-packages 102 that are disposed therein. Each of the plurality of wells 112 fills with molted metal during a pouring operation. The metal portions left after the metal in the mold assembly has solidified, which can weigh about 75 lbs. (43 kg.) are not part of the components being manufactured and are removed during a finishing operation. The metal slugs that are left over after the metal portions have been removed can typically be recycled. It is desirable to minimize the amount of metal that is poured into each mold assembly during the casting operation, and it is also desirable to minimize the amount of metal that is unused in the components being made. This amount of metal that is unused by the components that fills each of the plurality of wells 112 depends on the size and volume of the wells 112.
The wells 112 that are typically used are large enough to accommodate grippers 200 that engage each core-package 102 while handling each core-package 102 for and during deposition into the mold-half 100 or any other operation. Each gripper 200 is typically connected to a depositor machine 202, and is capable of pivotal motion with respect to the machine 202. The grippers 200 are typically used in pairs in a configuration whereby each set of grippers 200 opposingly engage a section of the core-package 102, as shown in the cross-section view of FIG. 2. The opposing configuration of the grippers 200 is necessary to avoid impartation of shear loads onto the section of the core-package 102 being engaged that may damage the brittle core-package 102. Even so, often times it has been observed that compressive loads imparted onto core-packages by grippers may cause damage and breakage in the core-packages, which in turn increase scrap rates in the manufacturing processes.
The cross-section of FIG. 2 shows each gripper 200 with solid lines in an engaged position, and in dotted lines in a disengaged position, for example, when the core-package 102 has been deposited in the cavity 104 of the mold-half 100 and the machine 202 is retracting upwards. Each gripper 200 has a head portion 204 that engages the core-package 102 at a recess portion 206 thereof that is formed along a region of the core-package 102 that lies downward while the core-package 102 is resting in the mold-half 100.
An outline view of a typical core-package 102 is shown in FIG. 3. The core-package 102 is presented from a bottom-surface 300 perspective or from a perspective visible by the mold-half 100 as the core-package 102 is being lowered into the cavity 104. The core-package 102 has a plurality of legs 302 of common height but of various configurations that contact a bottom surface of the cavity 104 of the mold-half 100 while the core-package is deposited therein. A height of the legs 302 determines a thickness of metal along the bottom surface 300 of the core-package 102 after the component has been molded and hardened. The plurality of recess-portions 206 that are arranged to accept the grippers 200 are also visible. There are four recess-portions 206 in the core-package 102 shown, but other numbers can be used for larger core-packages. The four recess-portions 206 are arranged in two opposing pairs for the reasons described. After a component has been formed around the core-package 102, each of the four recess-regions 206 has filled with solidified molten metal and adds unnecessary weight to the component. It is desirable to decrease such a “dead weight” in components being manufactured. The issues described thus far, and other issues, may advantageously be avoided as described below.
An outline view of an improved core-package 402 is shown in FIG. 4. The core-package 402 includes legs 404 that are similar to the legs 302 of the core-package 102 shown in FIG. 3. The legs 404 protrude from a bottom surface 405 of the core-package 402. The core-package 402 also includes a plurality or recess-portions 406 that at least partially extend around the bottom surface 405 to form a plurality of dents 408. Compared to the typical recess-portions 206, the recess portions 406 of this embodiment are advantageously fewer and shallower to reduce the amount of unnecessary metal in the finished part.
Detailed cross-section views of the improved core-package 402 during deposition into an improved mold-half 500 by use of an improved gripper 502 that is attached to a depositor machine 504 are shown in FIG. 5 and FIG. 6. The improved gripper 502 includes an elongate shaft 506 that is connected to the machine 504 on one end, and has a head portion 508 that is connected to the shaft 506 on another end and that protrudes laterally therefrom. The gripper 502 is advantageously capable of rotating by at least 90 degrees with respect to the machine 504, and because it does not pivot, it advantageously requires a smaller footprint with which to engage and disengage with the core-package 402.
During deposition of the core-package 402 into the mold-half 500, the gripper 502 is rotated such that the head portion 508 protrudes from the shaft 506 in a direction toward the core-package 402. The core-package 402 in this position is disposed around at least a portion of the gripper 502, with the shaft of the gripper 502 disposed at least partially within one of the recess-portions 406, and the head portion 508 of the gripper 502 disposed in contact with the dents 408 in the bottom surface 405 of the core-package 402.
After the core-package 402 has been deposited into the mold half 500, it disengages from the core-package 402 by rotating about the major axis of the shaft 506 such that the head portion 502 moves around and away from its respective recess 406. After the gripper 502 has rotated about 90 degrees or otherwise enough for the head portion 508 to clear the recess 406, the machine 504 lifts and pulls the grippers 502 out of the mold-half 500. Because the grippers 502 require less volume within which to engage the core-package 402, as compared to the pivoting grippers 200 shown in FIG. 2, a plurality of wells 512 that are formed in the mold-half 500 are considerably smaller and have considerably less volume than the wells 112 described earlier. This smaller volume is advantageous because it considerably reduces the amount of metal that will have to be removed after the casting operation is complete, and reduces waste material that would need to be recycled. Moreover, the lack of compressive force onto the core-package 402 considerably reduces the scrap rate of components in the manufacturing process.
An outline exploded assembly view of a drive mechanism 700 that may be used to operate each of the grippers 502 and is included in the machine 504 is shown in FIG. 7. The gripper 502 includes a gripper portion 702 and a drive portion 704. The gripper portion 702, as described above, includes the shaft 506 and head 508, and is what protrudes from the machine 504. The drive portion includes a first stop 706 that is coaxially connected to an end of the shaft 506 opposite the head 508. A bearing 708 is connected coaxially with the first stop 706, and a second stop 710 is connected coaxially in series with the bearing 708. A circular gear or pinion 712 is connected to the second stop 710. The pinion 712 has a plurality of teeth formed therein that are arranged along a periphery of the pinion 712, and constructed to mesh with a plurality of teeth formed in a linear gear or rack 714. When the machine 504 is fully assembled and operating, the pinion 712 is meshed with the rack 714.
The rack 714 is connected to a drive shaft 716. The drive shaft 716 is operably connected to an actuator 718 that is capable of causing the shaft 716 to reciprocally move with respect to the gripper 502. The actuator 718 can be any type of actuator capable to selective motion. For example, the actuator 718 can be a hydraulic or pneumatic cylinder, an electric motor or linear solenoid, and so forth. The reciprocal motion of the shaft 716 causes rotation of the gripper 502 due to the meshing between the rack 714 and pinion 712.
An outline view of one embodiment for a portion of the machine 504 is shown in FIG. 8. The machine 504 includes a frame 800 that has four sleeves 802 attached thereto. Each sleeve 802 forms an opening 804 that slideably engages a post (not shown) that allows the machine 504 to selectively move along the post, in either direction, during operation. An equipment-plate 806 is connected to the frame 800. The plate 806 has many different components mounted thereto, and also serves as a platform for connecting various actuators and other components (not shown) that are used during operation of the machine 504. This embodiment of the machine 504 is configured to handle three core-packages at any one time. Hence, many of the components that are connected onto the plate 806 are arranged generally in sets of three, but other arrangements may be used.
The plate 806 includes three pluralities of grippers 808. Each plurality of grippers 808 comprises three grippers each that surround one of three core-package pads 810. During operation of the machine 504, anywhere from one to three core-packages may be engaged into one or more of the three pads 810. Each core-package can be retained to the machine 504 by engagement to the three corresponding grippers 808 as described above.
There are additional features or components connected to the plate 806 that facilitate retention and alignment of core-packages. A plurality of retainers 812 are connected to the plate 806. Each of the retainers 812 includes a pin that selectively extends and retracts such that a core-package disposed within a pad 810 is pushed away from each pad 810 and against the corresponding grippers 808 for stability during transport. In the embodiment shown, there is one retainer 810 that corresponds to each pad 810, for a total of three retainers 812, but more retainers 812 can be used.
A plurality of alignment posts 814 are connected to the plate 806. The alignment posts 814 are arranged to align each core-package being transported to the respective grippers 808 and pad 810. The alignment posts 814 are arranged in two sets per pad 810, and disposed adjacent to an outer perimeter of the plate 806. During operation of the machine 504 at times when one or more core-packages are engaged with one or more sets of grippers 808, each alignment post 814 may contact and/or be in close proximity to a respective core-package. Other components, such as actuator(s) (not shown) or linkages (not shown) can also be connected or associated with the plate 806. These other components are constructed to selectively control the motion or the grippers 808, the retainers 812, and/or the motion of the frame 800.
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1. A machine for depositing at least one core-package into a cavity of a mold, the machine comprising:

a frame that is moveable in two directions, wherein a plurality of grippers is connected to the frame, wherein each gripper comprises:

a drive portion that includes a driven gear,

a shaft portion having an elongate shape with a centerline, wherein the shaft portion is connected to the drive portion, and

a head portion connected to the shaft portion on a distal end thereof that is opposite the drive portion, wherein the head portion extends past an outer dimension of the shaft portion;

at least one actuator connected to at least one drive shaft through at least one linkage, wherein each linkage includes at least one driver gear;

wherein the at least one driver gear is meshed with the driven gear of the at least one gripper such that a motion of the actuator is transferred to the drive shaft, a motion of the drive shaft is transferred to the driver gear, a motion of the driver gear is transferred to the driven gear, and a motion of the driven gear is transferred to the gripper; and wherein the motion of the gripper is a rotational motion about the centerline.

2. The machine of claim 1, wherein the machine defines at least one pad for accepting a core-package, and wherein there are three grippers connected to the machine for each pad.

3. The machine of claim 2, further comprising at least one alignment post operably associated with the frame and disposed adjacent to a periphery of the at least one pad.

4. The machine of claim 2, further comprising at least one retainer operably associated with the frame, wherein the at least one retainer includes a reciprocating pin that at times selectively extends to push a core-package against one or more head portions of the plurality of grippers.

5. A method of handling one or more core-packages during construction of a mold, comprising the steps of:

readying a core-package for placement into a mold cavity;

aligning the core-package onto a shipping surface;

positioning a machine having a receiving surface over the core-package;

lowering the machine over the core-package such that the core-package becomes disposed adjacent to the receiving surface;

disposing two or more grippers that are attached to the machine, each gripper having an elongate shaft with a centerline, into respective recesses of the core-package;

rotating each of the two or more grippers about its centerline such that a head portion disposed on an end of each gripper is positioned underneath the core-package.

6. The method of claim 5, further comprising the steps of:

raising the machine while the core-package is engaged by the two or more grippers;

moving the machine to a new position over a mold cavity;

lowering the machine over the mold cavity such that the core-package is disposed within the mold cavity;

rotating the two or more grippers such that their respective heads are no longer underneath the core-package;

raising the machine away from the mold cavity leaving the core-package disposed in the mold cavity.

7. The method of claim 5, further comprising the steps of:

activating a retainer having a reciprocally mounted pin such that the pin extends to push the core-package against the head portions of the two or more grippers; and

selectively retracting the pins.

8. A method of handling a core-package for placement into a mold cavity formed in a mold, comprising the steps of:

engaging a core-package with a depositor machine, wherein the depositor machine has a plurality of grippers protruding therefrom, wherein each gripper comprises an elongate shaft having a centerline and a head disposed on a distal end of the elongate shaft, wherein the head protrudes laterally from the elongate shaft, and wherein each gripper is advantageously capable of rotating by at least 90 degrees with respect to the depositor machine;

wherein the step of engaging the core-package with the depositor machine is accomplished by rotating each gripper in a first direction such that each head moves around the centerline in a direction toward the core-package until each head is disposed beneath the core-package;

disengaging the core-package from the depositor machine;

wherein the step of disengaging the core-package from the depositor machine is accomplished by rotating each gripper about the centerline in a second direction that is opposite the first direction of rotation such that each head moves around the centerline in a direction away from the core-package until each head clears the core-package completely.

9. The method of claim 8, wherein the step of rotating each gripper along the first and second directions is accomplished by activating an actuator, wherein the actuator is connected to a drive shaft having a rack gear, wherein each gripper includes a pinion hear that is meshed with the rack gear, and wherein the actuator causes the drive shaft to move reciprocally such that the rack gear causes the pinion gear to rotate.

10. The method of claim 8, further comprising the steps of:

raising the depositor machine while the core-package is engaged by two or more grippers;

moving the depositor machine to a new position over the mold cavity;

lowering the depositor machine over the mold cavity such that the core-package is disposed within the mold cavity; and

raising the depositor machine away from the mold cavity.

11. The method of claim 8, further comprising the steps of:

activating a retainer having a reciprocally mounted pin such that the pin extends to push the core-package against each head at times when the core-package is engaged to the depositor machine; and

selectively retracting the pins.