Patent ID: 12246928

DETAILED DESCRIPTION

The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element or region to another element or region as illustrated in the accompanying drawings. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the drawings.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used herein specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Disclosed herein are a fluid-operated gripping apparatus for holding a workpiece (e.g., such as a honeycomb body) in a working orientation, and associated methods for gripping and holding a workpiece using such an apparatus. Fluid-operated first, second, and third actuators, each comprising an actuator rod coupled with a moveable piston arranged within a cylinder, are equally spaced around a perimeter of a workpiece and configured to be coupled to a single pressurized fluid source. A fluid circuit (e.g., a pneumatic or hydraulic circuit) is provided to cause the actuators to extend (i.e., during a closing stroke of the gripping apparatus) according to the force equalization principle. The fluid circuit also serves to cause the actuators to retract (i.e., during an opening stroke of the gripping apparatus). Each actuator may comprise an extend chamber and a retract chamber, and therefore embody a double-acting cylinder. An end of each actuator comprises an end effector having a three-degree-of-freedom rotational joint and being configured to contact a surface of the workpiece at exactly two points (thereby serving as a kinematic contact). This avoids avoid over-constraining the workpiece, thereby permitting orientation of the workpiece (e.g., relative alignment of an axis of the workpiece) to be maintained while gripping is performed. In certain embodiments, over-constraining the workpiece may be further avoided by providing a backstop configured to contact an end face of the workpiece, with the backstop being coupled with a three-degree-of-freedom (3DOF) rotational backstop joint. The gripping apparatus easily accommodates workpieces of various sizes (e.g., diameters) without requiring particular

FIGS.2A and2Billustrate a portion of a gripping apparatus30according to one embodiment, withFIG.2Aproviding a bottom plan view andFIG.2Bproviding a side cross-sectional view taken along section line2B-2B shown inFIG.2A. The gripping apparatus30comprises fluid-operated first, second, and third actuators32A-32C that are arranged 120 degrees apart from one another and supported by (e.g., suspended from) a structural mounting ring50using intermediately arranged mounting brackets54A-54C. As shown, the actuators32A-32C are arranged in a substantially horizontal plane. Referring toFIG.2A, each actuator32A-32C comprises a cylinder38A-38C and points radially inward toward a center of a circular opening52defined by the structural mounting ring50. Each actuator32A-32C additionally comprises an end effector44A-44C having a joint48A-48C and a forked end portion46A-46C. In certain embodiments, the joints48A-48C may embody pivot joints capable of pivotal movement relative to a single plane. In certain embodiments, the joints48A-48C may embody 3DOF joints (e.g., ball joints) capable of pivotal movement relative to a multiple planes. A backstop60having a workpiece receiving surface62is centrally arranged within the opening52of the structural mounting ring50. As shown inFIG.2B, the backstop60has an associated three-degree-of-freedom (3DOF) rotational backstop joint64to permit pivotal movement in multiple planes relative to an upper support element (not shown). As shown, the 3DOF rotational backstop joint64may comprise a ball joint, or may comprise multiple pivotal joints each allowing pivotal movement in a different plane.

With continued reference toFIG.2Bin which internal portions of the first actuator32A are shown, the first actuator32A comprises a piston34A and an actuator rod36A coupled to the piston34A, with the piston34A being configured to move within the cylinder38A. The cylinder38A comprises an extend chamber40A and a retract chamber42A, thereby embodying a double-acting cylinder. Pressurization of the extend chamber40A causes the actuator rod36A to extend outwardly relative to the cylinder38A, and pressurization of the retract chamber42A causes the actuator rod36A to retract into the cylinder38A. InFIGS.2A and2B, each actuator32A-32C is shown in a retracted positon. With continued reference toFIG.2B, the extend chamber40A and the retract chamber42A may be selectively pressurized with pressurized fluid (e.g., liquid or gas) through a fluid circuit (such as described hereinafter in connection withFIGS.4A-4C). It is to be appreciated that the second and third actuators32B,32C may be identical to the first actuator32A, thereby comprising elements corresponding to those illustrated and described in connection with the first actuator32A.

FIG.3is a perspective view of an end effector44A as shown inFIGS.2A and2Barranged in contact with a cylindrical workpiece20(which may embody a honeycomb body) at two single points of contact68A-1,68A-2. The end effector44A comprises a forked end portion46A that defines first and second curved contact surfaces66A-1,66A-2each having a convex curvature and configured to contact a cylindrical wall26of the cylindrical workpiece20(which extends between end faces22,24thereof) at a single contact point68A-1,68A-2, such that the end effector44A as a whole is configured to contact the cylindrical workpiece20at exactly two contact points68A-1,68A-2. The end effector44A further comprises an axial body portion70A defining a central opening72A through which an actuator rod or rod extension structure (not shown) may be inserted. The axial body portion70A further comprises a vertical bore74A that may receive a pin or other structure (not shown) that couples the end effector44A with a pivotal joint48A. In certain embodiments, the end effector44A may be configured to pivot in a single (e.g., horizontal) plane relative to an associated actuator rod (not shown). In certain embodiments, the end effector44A may be configured to pivot along multiple planes relative to an associated actuator rod, such as by providing a single 3DOF rotational joint (e.g., a ball joint) or multiple sequentially arranged two-degree-of-freedom (2DOF) joints therebetween. By contacting a cylindrical workpiece at exactly two points with each of three end effectors (such as the end effector44A), and providing end effectors that are pivotally coupled to associated actuator rods, the workpiece is not over-constrained, thereby permitting orientation of the workpiece to be maintained while gripping is performed.

FIG.4Ais a top plan view of an end effector44A as shown inFIGS.2A,2B, and3, with contour lines provided along visible surfaces. The end effector44A comprises a forked end portion46A that defines first and second curved contact surfaces66A-1,66A-2each having a convex curvature. As shown, the first and second curved contact surfaces66A-1,66A-2are arranged 120 degrees apart from one another. The end effector44A comprises an axial body portion70A that comprises a vertical bore74A arranged to receive a pin or other structure (not shown) for coupling the end effector44A with a pivotal joint (not shown) permitting pivotal movement along one or multiple planes (e.g., as a 2DOF or 3DOF joint) between the end effector44A and an actuator rod (not shown).FIG.4Bis a cross-sectional view of a segment of the forked end portion46A of the end effector44A, taken along section line4B-4B shown inFIG.4A, showing curvature of the curved contact surface66A-1. As shown, a radius of curvature R of the curved contact surface66A-1may exceed a body thickness of the forked end portion46A. In certain embodiments, the end effector may be fabricated of a polymeric material (e.g., polyethylene, polyurethane, ABS, polyimide, silicone, etc.) having coefficient of friction, surface finish, and durometer properties in sufficient ranges to facilitate gripping of a workpiece (e.g., a ceramic honeycomb body, either before or after complete solidification) without conferring damage to sidewall surfaces thereof.

FIG.5Ais a diagram of a fluid circuit80showing interconnections between a pressurized fluid source82, valves84,86A-88C,88A-88C, fluid lines90, and fluid-operated first through third actuators32A-32C according to one embodiment of the present disclosure, with the fluid circuit80being configured to cooperate with components such as shown inFIGS.2A-2Bas part of a gripping apparatus for holding a workpiece in a working orientation. Each actuator32A-32C comprises a piston34A-34C with an actuator rod36A-36C coupled thereto, with the piston34A being configured to move within a cylinder38A-38C. Each cylinder38A-38C embodies a double-acting cylinder, comprising an extend chamber40A-40C and a retract chamber42A-42C to permit fluid-controlled movement of the piston34A-34C for both extension (i.e., during a closing stroke of a gripping apparatus) and retraction (i.e., during an opening stroke of a gripping apparatus) of the piston34A-34C. A pressure admission valve84is coupled with the pressurized fluid source82, and may be coupled with a vent or drain (not shown). In certain embodiments, the pressure admission valve84may comprise a five-port, two-position, four-way valve, although other types and/or combinations of valves may be used in certain embodiments. Downstream of the pressure admission valve84, first through third actuator-specific valves86A-86C are provided in parallel, to selectively (i) admit pressurized gas into the extend chamber40A-40C of each cylinder38A-38C and (ii) admit pressurized gas into the retract chamber42A-42C of each cylinder38A-38C. In certain embodiments, each actuator-specific valve86A-86C comprises a three-port, two-position, three-way fluid-piloted valve, although other types and/or combinations of valves may be used in further embodiments. The extend chamber40A-40C of each cylinder38A-38C has an associated check valve88A-88C to inhibit flow of pressurized fluid from one cylinder38A-38C to another cylinder38A-38C. The check valves88A-88C enable pressure to equalize during the closing stroke of a gripping apparatus, which in turn allows an end effector (not shown) of every actuator32A-32C to come into contact with a surface of a workpiece and the same pressure level to be attained in the extend chamber40A-40C of each cylinder38A-38C. By disallowing backflow, the check valves88A-88C ensure that extend chamber pressure is maintained, thereby keeping a workpiece held in position. Since the check valves88A-88C disallow backflow of pressurized fluid, an alternative path for fluid escape path is provided to permit the actuators32A-32C to be moved to a retracted position. This is provided with the actuator-specific valves86A-86C, since when the retract chambers42A-42C are pressurized, the actuator-specific valves86A-86C are triggered, permitting pressurized fluid to be exhausted from the retract chambers42A-42C.

FIGS.5B and5Cillustrates the fluid circuit80ofFIG.5Aduring a closing stroke and during an opening stroke, respectively, of a gripping apparatus according to one embodiment. Such figures will be described hereinafter, following discussion of preparatory steps that may be employed when a gripping apparatus is used with a plugging apparatus such as a vertical pattie plunger for plugging selected flow channels of a honeycomb body. For example, during fabrication of a honeycomb body, an extruded cylindrical ceramic body comprising a honeycomb structure having internal flow channels may be further processed by a piston-actuated vertical pattie plunger that is used to plug selected flow channels. In such a process, the face alignment of the honeycomb body relative to a piston surface of the vertical pattie plunger helps to allow a more uniform depth of plugs inserted into internal flow channels of the honeycomb body. After plugging material or plugs are inserted into the end face of a honeycomb body, such plugs may be dried in place, optionally aided by heating to high temperatures. Achieving adequate face alignment of a honeycomb body relative to a piston surface of a vertical pattie plunger can be burdensome, as the honeycomb body must be gripped by the cylindrical sidewall (as at least one end face of the honeycomb body must be exposed and is unavailable for gripping), and it is advantageous to maintain the honeycomb body in a working orientation not altered by the gripping process. This gripping task can be further complicated by the need to work with honeycomb bodies of different sizes (e.g., diameters) and/or shapes.

In certain embodiments, a honeycomb body may be positioned on top of a press piston and centered thereon. At least a portion gripping apparatus as described herein may then be lowered until a swivelable (e.g., 3DOF rotatable) backstop of the gripping apparatus contacts a top surface of the honeycomb body and sufficient contact force is exerted therebetween to withstand any backlash and prevent the honeycomb body from slipping. Thereafter, valves of a fluid circuit such as described inFIG.5Amay be operated to cause the honeycomb body to be gripped in position, with actuators extended to cause end effectors to contact a curved sidewall of the honeycomb body.

FIG.5Billustrates the fluid circuit80ofFIG.5Aduring a closing stroke of a gripping apparatus. As shown, pressurized fluid flows from the pressurized fluid source82through the pressure admission valve84and check valves88A-88C to the actuator-specific valves86A-86C, which are configured to admit the pressurized fluid into the extend chamber40A-40C of each cylinder38A-38C. Presence of pressurized fluid in the extend chambers40A-40C causes the pistons34A-34C and associated actuator rods36A-36C to move in a direction from the extend chambers40A-40C toward the retract chambers42A-42C (as depicted by the hollow arrows shown inFIG.5B) into an extended position, according to a closing stroke of the gripping apparatus in which end effectors (not shown) associated with the actuator rods36A-36C are translated toward an outer surface of a workpiece. With the actuators32A-32C coupled in parallel to the same pressurized fluid source82, only the actuator32A-32C experiencing the least resistance to extension will move, and backflow of pressurized fluid is prevented by the check valves88A-88C. Upon contact of one actuator end (e.g., an end effector coupled with an actuator rod36A-36C) with the workpiece, resistance of the actuator to further movement will increase, and then another actuator will move until its end contacts the workpiece, and the process will continue until end effectors of all three actuators32A-32C have contacted the workpiece and the pressure is equal in the extend chambers40A-40C of all three actuators32A-32C. In such a state, equal force is applied by the three actuators32A-32C to a curved outer surface of the workpiece, and such force as long as fluid pressure is maintained in the extend chambers40A-40C. Notably, the force exerted by the actuators32A-32C is directly proportional to the fluid pressure supplied to the extend chambers40A-40C, such that the exerted force may be adjusted by simply altering a pressure of fluid supplied by the pressurized fluid source82. In certain embodiments, the pressurized fluid source82may comprise an adjustable pressure regulator (not shown) to facilitate adjustment of force exerted by the actuators32A-32C on a workpiece gripped by a gripping apparatus incorporating the fluid circuit80.

FIG.5Cillustrates the fluid circuit80ofFIG.5Aduring an opening stroke of a gripping apparatus. The pressure admission valve84is moved to a position to supply pressurized fluid to the retract chamber42A-42C of each cylinder38A-38C. At the same time, pressurized fluid is supplied to the actuator-specific valves86A-86C to change the valve position by piloting, thereby permitting pressurized fluid contained in the extend chambers40A-40C to be exhausted through the actuator-specific valves86A-86C. By simultaneously pressurizing the retract chambers42A-42C and depressurizing the extend chambers40A-40C, each piston34A-34C is caused to move in a direction from the retract chamber42A-42C toward the extend chamber40A-40C, as depicted by the hollow arrows shown inFIG.5C.

FIG.6is a perspective view of at least a portion of a gripping apparatus as shown inFIGS.2A and2B, showing the fluid-operated first, second, and third actuators32A-32C with associated end effectors44A-44C configured to receive a cylindrical workpiece therebetween, showing a swivelable backstop60arranged above the actuators32A-32C, and showing a structural mounting ring50supporting the actuators32A-32C. The structural mounting ring50defines an opening54, and at least a portion of the backstop60(having a workpiece receiving surface62) is centrally arranged within or proximate to the opening54. The actuators32A-32C are arranged to be equally spaced about a perimeter of a workpiece (120 degrees apart from one another) and are supported by (e.g., suspended from) the structural mounting ring50with mounting brackets54A-54C. Each actuator32A-32C comprises a cylinder38A-38C that receives fluid lines90for supplying pressurized fluid to extend and retract chambers of the cylinder38A-38C. Each actuator32A-32C is coupled with an associated end effector44A-44C via a joint48A-48C, which may comprise a ball joint in certain embodiments. A support structure for the structural mounting ring50may comprise threaded risers94that may be caused to rotate to change vertical position of the structural mounting ring50(e.g., with a workpiece gripped between end effectors44A-44C of the actuators32A-32C), such as may be useful during a GPF plugging process utilizing a vertical pattie plunger (not shown).

FIG.7is a perspective view of a cylindrical workpiece (i.e., a honeycomb body)20arranged within the gripping apparatus portion ofFIG.6. The honeycomb body20comprises a cylindrical wall that extends between opposing end faces22,24. As shown, the honeycomb body20has removable masks96-1,96-2affixed to the end faces22,24. In certain embodiments, the masks96-1,96-2may have multiple holes defined therein and may be used as part of a plugging step by which plugging material is supplied through the holes into selected flow channels of the honeycomb body20and pressed into place at a specified depth using a vertical pattie plunger (not shown). As shown, an upper end face24of the honeycomb body20is arranged against the workpiece receiving surface62of the backstop60positioned within the opening52of the structural mounting ring50. The honeycomb body20is positioned to be gripped laterally by end effectors44A-44C that are coupled by joints44A-44C to actuator rods36A-36C of actuators32A-32C, which are supported by the structural mounting ring50using brackets54. Fluid lines90are provided to supply pressurized fluid to the actuators32A-32C, and threaded risers94are provided to enable vertical position of the structural mounting ring to be adjusted. Operation of the apparatus shown inFIG.7proceeds according to steps outlined previously herein.

Although specific embodiments disclosed herein are particularly beneficial for use with workpieces having opposing circular end faces bounding a cylindrical sidewall, it is to be appreciated that gripping apparatuses disclosed herein may be used with workpieces of other shapes, such as: workpieces having one or more curved sidewalls; workpieces having at least one hemispherical or non-planar end face bounding a cylindrical sidewall; workpieces having one or more oval end faces bounding a cylindrical side wall; workpieces having workpieces having substantially polyhedral end faces (e.g., with six, seven, eight, nine, ten, eleven, twelve or more sides, optionally having rounded corners) and sidewalls of the same or similar shape, and the like. Additionally, although specific embodiments disclosed herein relate to use of a gripping apparatus comprising fluid-operated first, second, and third actuators and associated end effectors, it is to be appreciated that additional actuators (e.g., fourth, fifth, sixth, etc.) and associated end effectors may be provided in certain embodiments. In this regard, at least three actuators and associated end effectors may be provided in certain embodiments.

Technical benefits that may be realized by one or more embodiments disclosed herein include: enhanced ability to automatically grip a workpiece having curved (e.g., cylindrical) sidewalls, particularly while maintaining the workpiece in a working orientation; enhanced ability to automatically grip workpieces of different sizes (e.g., diameters) without adjustment; improved ease in adjusting gripping force exerted against sidewalls of workpieces having curved sidewalls; enhanced speed and ease of performing GPF plugging experiments; increased throughput of GPF production; and reduced labor requirements for GPF experimentation and production.

Those skilled in the art will appreciate that other modifications and variations can be made without departing from the spirit or scope of the invention. Since modifications, combinations, sub-combinations, and variations of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and their equivalents.