Automated tile placement machine

Methods and apparatus are provided for the automated assembly of individual tiles on a surface in a predetermined pattern. In one exemplary embodiment, an automated apparatus comprises a tile dispenser with an open ended shoe portion adapted for holding a stack of regularly shaped tiles, and a tile advancement mechanism for incrementally advancing tiles in the shoe toward the open end thereof. The automated apparatus may further comprise a robotic mechanism adapted to retrieve a tile from the end of the tile stack, and place the tile on the surface.

TECHNICAL FIELD AND BACKGROUND

The instant invention relates generally to surfaces and panels comprising individual tiles arranged in a predetermined pattern, and methods of constructing such surfaces and panels. The technical field may include, for example, ballistic armor panels comprising regularly shaped ballistic grade ceramic tiles arranged in a close fitting assembly on a backing made of ballistic resistant composite materials.

DESCRIPTION OF THE EMBODIMENTS

The instant invention is described more fully hereinafter with reference to the accompanying drawings and/or photographs, in which one or more exemplary embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be operative, enabling, and complete. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention. Moreover, many embodiments, such as adaptations, variations, modifications, and equivalent arrangements, will be implicitly disclosed by the embodiments described herein and fall within the scope of the present invention.

Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Unless otherwise expressly defined herein, such terms are intended to be given their broad ordinary and customary meaning not inconsistent with that applicable in the relevant industry and without restriction to any specific embodiment hereinafter described. As used herein, the article “a” is intended to include one or more items. Where only one item is intended, the term “one”, “single”, or similar language is used. When used herein to join a list of items, the term “or” denotes at least one of the items, but does not exclude a plurality of items of the list. Terms such as “connected” or “attached” as used herein are intended to denote direct, indirect (with intermediate elements), rigid, and flexible linking arrangements, as well as linking arrangements with one or more degrees of freedom.

Referring now to the drawing figures, an exemplary automated tile placement machine in accordance with the present disclosure is indicated generally inFIG. 1at reference numeral10. The operative mechanical elements comprise a linearly movable assembly table12, left and right robots14mounted above the assembly table12to a gantry18, and left and right tile dispensers in the form of automatic tile feeders20. The tile placement machine10may further include automatic control elements, comprising for example left and right machine controllers21, a programmable logic controller (PLC)28, a human machine interface (HMI) station30, and a perimeter encroachment sensor13. In general, the tile placement machine retrieves individual tiles one at a time from the tile feeders20, and assembles them on the movable assembly table12in a predetermined pattern. The tile placement machine may be utilized in this manner, for example, to assemble ballistic armor panels using ballistic grade ceramic tiles arranged in a specific manner dictated by a particular tactical application.

FIG. 2depicts an exemplary tile dispenser in the form of automatic tile feeder20. The tile feeder20includes a shoe22that is essentially an elongated channel with an open end23, and adapted to hold a stack of regularly shaped tiles. The shoe22may include protruding guide rails24along the sides and bottom of the channel to facilitate tile alignment and to guide the tiles as they advance through the shoe toward the open end23. In the depicted embodiment, there are two evenly spaced guide rails24in the bottom of the channel, and one guide rail24on each side. The guide rails may be of any cross-sectional shape, such as flat or round, and made from any dimensionally stable material having a relatively low friction coefficient, particularly with respect to ceramic. For example, in one exemplary embodiment the guide rails are round steel rods.

In addition to guiding the tiles, the guide rails24may also act as tracks for a trolley32, best seen inFIGS. 3 through 6. The trolley32is a tile advancement mechanism, essentially in the form of a motor driven push plate for incrementally advancing a stack of tiles in the shoe22toward the open end23. In the illustrated embodiment the trolley mechanism32comprises an upper carriage34and lower carriage36movably disposed on opposite sides of the shoe floor38. The front of the upper carriage34comprises a push plate35that defines the effective length of shoe22, and in operation bears directly against the stack of tiles. As best seen inFIG. 5, the shoe floor38has a central slot40to allow for a mechanical connection41between the upper and lower carriages34,36. The shoe floor38also has a pair of spaced apart guide rails24on the bottom side mirroring those on the top side of the floor, with both sets of rails24serving as tracks for the wheels42of both upper and lower carriages. Thus the trolley32is freely movable along the length of shoe22via wheels42rolling along the rails24on both sides of shoe floor38.

Referring now toFIG. 7and alsoFIG. 3, the trolley mechanism32is positively advanced along the shoe22by means of a linear actuator, indicated generally at reference numeral44. The linear actuator44may be any suitable form of known mechanical, electrical, or hydraulic device, or combination thereof adapted for incrementally advancing the trolley32. For example, in the illustrated embodiment the linear actuator44comprises a drive track46containing a lead screw (not shown) rotatably driven by a motor48. The trolley mechanism32is slidably connected to the drive track46by a guide housing50, and operatively engaged with the lead screw by a lead nut internal to housing50. The trolley mechanism32, along with tiles stacked in front of the push plate35may thus be incrementally advanced along the shoe22toward the open end23by starting and stopping motor48in a controlled manner.

In accordance with one embodiment the linear actuator44via motor48is started and stopped in response to sequenced electronic signals. For example, the actuator may be started in response to a first signal generated by the control system, and stopped in response to a second signal generated by a position sensor. The first signal may be automatically generated by the control system in response to a particular preceding event, such as the removal of a tile from shoe22by a robot14. Upon receiving the first signal, the actuator44begins pushing the stack of tiles toward the open end23of shoe22.

A second signal may be generated using a tile position sensor to detect when the stack of tiles in shoe22has advanced by a certain amount such as by the thickness of one tile. Referring toFIG. 8, an exemplary position sensor in the form of a laser switch52is located at the open end23of shoe22, and aimed directly across the path of the advancing tile stack. The laser switch52is tripped when the front tile of the stack breaks the beam, generating a second signal, and stopping the linear actuator and tile stack at that point. Then, once the front tile is removed by a robot14, a first signal is again generated by the control system, and the above described sequence repeats.

The open end23of shoe22may further comprise registration means for accurately and consistently positioning the front tile for robot pick up. For example, in the embodiment shown in the drawings, the registration means involves pushing the tile against a physical stop. Referring again toFIG. 8, the pushing is accomplished using upper and lower pneumatic actuators56disposed on one side of the open end23of shoe22. The actuators are positioned to be aligned with the edge of the front tile in a stack, and may be vertically positioned to work with standard tile sizes, such as 4 inch square tiles, or 2 inch×4 inch rectangular tiles. When activated, the moving portions58of one or both actuators56extend toward the edge of the front tile, driving the tile laterally against the guide rail24on the opposite side of the shoe22. The actuators may then be retracted, leaving the tile in contact with one side rail24and both bottom guide rails24. The resulting three point contact with the guide rails24provides a repeatable tile position for facilitating consistent retrieval by a robot14.

As shown inFIG. 1, the tile placement machine10may comprise two automatic tile feeder20adjacent each side of the table12. The tile feeders20are positioned such that the shoes22are tilted back at an angle to the horizontal with the open end23elevated. Tilting the shoe back in this way serves to keep the stacked tiles together and against push plate35, as well as reducing the tendency for the front tile in the stack to topple out of the shoe. The shoe may also include flexible tabs54located on the end of the shoe near the top, that project into the path of the advancing tile stack for providing additional security to the front tile. The tabs54are stiff enough to prevent the front tile from falling after the linear actuator stops, but flexible enough to be easily displaced by the edge of the front tile when tile is withdrawn by the robot14for placement on the movable table12.

Once accurately positioned at the end of the shoe, the front tile in the stack is retrieved by a robot14and placed in a predetermined position on the table12. The robot14may comprise various robotic mechanisms or combinations of mechanisms. For example, in the embodiment shown inFIG. 1, robot14is a high precision, six axis robot of the type typically used for industrial manufacturing and assembly. One such example of a suitable commercially available six-axis robot is the model IRB140sold by The ABB Group, located in Zurich, Switzerland.

Robot14may be fixed to the gantry18at a location such that it can reach the tile feeders20on one side of the table12, and at least one half of the table. As can be seen with reference toFIG. 1, the tile placement machine10may be configured with left and right robots14and tile feeders20for accessing respective left and right halves of table12. It should be appreciated that additional degrees of freedom may be added to the robotic system, such as for example the ability to translate the robots laterally with respect to gantry18, should such capability be desirable or more efficient for a particular machine configuration.

Tiles are retrieved from the tile feeders20using a suitable chuck, or end effector on the robot14.FIG. 9depicts an exemplary vacuum type end effector60comprising a mounting bracket62for attachment to the robot, a hollow post64extending from bracket62, and a chuck assembly65at the end of post64. Chuck assembly65comprises a chuck plate66with four compliant tile supports68, one at each corner of plate66on the side opposite post64. Each compliant tile support68comprises a spring loaded pin70in an adjustable pin housing72. An internal compression spring biases the pin70out of the housing72, and provides compliance when the pin is pressed against a fixed object such as a tile.

The chuck assembly further comprises a rubber bellows74that extends from the center of chuck plate66on the same side as the tile supports68. The bellows74may comprise multiple segments76as shown, ending at a suction cup78. A contiguous vacuum passage through plate66, post64, and bracket62connects bellows74through a hose75to a vacuum pump located in robot14. A surface of an object may be gripped by placing the suction cup78against the surface and pumping down the pressure in bellows74. The reduced pressure holds the suction cup78firmly to the surface, and also causes bellows segments76to contract, thereby pulling the gripped object toward the chuck plate66and into pressing contact with spring pins70. It should be appreciated that the springs supporting pins70may be configured such that some or all of the pins70are forced at least partially into housings72from the force applied to the pins by a gripped object. The spring compliance and vacuum level may be effectively used in this manner to firmly seat a gripped surface against all four pins. A surface gripped by the end effector60may be released by simply releasing the applied vacuum.

FIG. 10depicts an assembly table12in accordance with the present disclosure, comprising generally a table top82mounted on a pair of frame rails84atop a base86. The table top82is a very flat and rigid plate made of a suitable high strength and warp resistant material such as aluminum. The top82is fitted with suitable bushings or rollers underneath that allow it to freely slide back and forth along frame rails84in the directions indicated by arrows “A”. A drive system comprising a motor88and lead screw90, similar in principle to the arrangement described above in reference to the shoe22, may be used to very accurately move and position the table top82at desired points along the frame rails84.

Referring toFIG. 11, the table top82may include an array of holes92for receiving steel dowel pins94used for positioning and fixing various articles to the table surface. For example, as will be described in greater detail below, the dowel pins94may be used as pilot surfaces to guide the edges of a tile being placed onto the table, or to accurately position a panel substrate onto which tiles will be placed. Dowel pins may also be conveniently used to mount fixtures or other articles to the table top, such as for example the panel assembly plate96as shown inFIG. 11. In particular, each panel assembly plate96may be pinned at two locations through mount holes97that are configured to align with a respective pair of holes92in the table. The dowel pins used in holes97are sized to be at least slightly below flush with the top of assembly plates96.

Taller dowel pins94may be located in holes92around and between the panel assembly plates96, and used for example to position a panel substrate98atop the panel assembly plate96as shown in the cross-section view ofFIG. 12. In the case of an armor panel, the panel substrate98may be a rigid, ballistic composite material forming an integral portion of the finished panel. As can be seen, the panel substrate98is larger than, and overhangs assembly plate96, facilitating hand removal of the panel substrate from the assembly table after a tile assembly process.

Instead of the holes and dowel pins described above, the table top82may alternatively comprise various other fixtures or systems for positioning or holding workpieces on the table. For example, in one alternative embodiment the table top includes an array of threaded holes for receiving threaded fasteners that may be used to pilot or clamp workpieces to the table top. In another alternative embodiment the table top is a vacuum chuck comprising an array of relatively small holes connected to a vacuum source. In addition, various other fixtures and mounting devices are foreseeable to those skilled in the art, and within the scope of the present disclosure.

The tile placement machine is capable of simultaneously assembling two tile panels by utilizing both robots14and tile feeders20on both sides of table12. As shown inFIG. 13, table12may be configured with multiple lanes of panel assembly stations200, such that half of the assembly stations are accessible by the left robot14, and half accessible by the right robot. The number of lanes, and the number of assembly stations per lane may of course vary depending upon the type and size of panels being constructed. For example, the machine could be used to assemble one large panel instead of multiple lanes of smaller panels, with the left and right robots14assembling their respective halves of the large panel.

The movable table embodiment ofFIG. 13comprises four lanes: lanes201and202on the left side; and lanes203and204on the right side. The table may be initially positioned with a first row208of four assembly stations, one from each of lanes201through204, located proximate robots14for initiating tile placement. So positioned, the left and right robots14may be operated to simultaneously assemble tile panels at left and right assembly station pairs206and207respectively of row208, moving the table top82as required during the assembly process. Once the four panels of row208are complete, the table may then be moved to a starting position for the next row (209) of assembly stations200to begin assembly of four more tile panels.

The tile placement machine is also capable of constructing tile panels using tiles of more than one type. The various tile types may include for example variations in tile size, shape, material, hardness, strength, color, surface finish, or other attributes. For example, referring again to the table assembly ofFIG. 13, a tile feeder20adjacent the left side of the table may contain a first tile type, used exclusively in panels constructed in lanes201and202, while a tile feeder on the right side of the table may contain tiles of a second type used exclusively in panels constructed in lanes203and204. Alternatively, the tile placement machine may comprise two tile feeders20adjacent each side of the table12, with one containing a first type of tile, and the other containing a second type of tile. In this kind of configuration, each robot is capable of constructing panels using exclusively the first or second types of tiles, or panels using both types of tiles.

In one exemplary embodiment, the tile placement machine comprises two tile feeders adjacent one another on each side of the table as shown for example inFIGS. 1 and 13, with one tile feeder on each side adapted for square tiles, and the other tile feeder adapted for rectangular tiles the size of a square tile cut in half. Of course the tile placement machine may be configured with more than two tile feeders per side, and more than two tile types as may be dictated by any particular application or production schedule.

An exemplary process of retrieving tiles from shoe22and assembling the tiles on table12will now be described. As an initial matter, the position of the table may be determined, and adjusted if necessary by translating the table top82along frame rails84. For example, in the above described embodiment in which a panel substrate98is located atop an assembly plate96, an appropriate position comprises positioning the table top82where a particular row of panel substrates98is properly positioned relative to the robots14for panel assembly to proceed.

A tile retrieval and placement sequence begins by moving the end effector60on robot14to a first position for engaging and capturing the front tile in a tile feeder20. Referring toFIG. 14, the shoe22of a tile feeder20is loaded with a stack of ceramic tiles310ready to be dispensed. A robot end effector60, such as the type described above in reference toFIG. 9, is brought into gripping engagement with the front tile312of the stack. The level of vacuum used for gripping is sufficient to pull the tile312firmly against and slightly compress all four spring loaded pins70of the end effector60.

With the tile312firmly gripped, the end effector60is moved straight away from the end of shoe22, taking the tile with it as the tile edges push the flexible tabs54out of the way.FIG. 15shows tile312positioned slightly away from the end of shoe22, having been pulled from shoe22by the end effector60. Through a series of coordinated movements the robot then brings the tile to the table above a location at which the tiles are to be assembled. For example, the robot may initially bring the tile to a position as shown inFIG. 16, immediately above and facing a panel substrate98positioned on table top82of assembly table12. Panel substrate98may be one of a plurality of such panels arrayed about the table top82, each mounted using dowel pins94and an assembly plate96in the manner described above in reference toFIGS. 11 and 12. If the table is not already in the proper position, it may be adjusted at this point as described above, prior to tile placement.

If the tile is the first tile to go on the panel substrate98, placement may simply comprise moving the tile to a position immediately above the intended placement position, and moving the end effector straight down until the tile is seated on the panel substrate98.FIG. 17depicts a first tile of a panel assembly being placed on the assembly plate96at the end of a movement directly downward by the end-effector from the position ofFIG. 16. Once the tile is seated, a downward force may be applied to the tile to press it onto the panel substrate98by continuing to move the end effector60toward the table. The compliance of the spring loaded pins70serves to regulate the pressing force and prevent overloading and damaging the tile. In addition, the surface of the panel substrate may have an adhesive treatment or film to hold the tile in place after the end effector60is withdrawn.

Having placed the tile, vacuum is released, and the end effector is lifted away from the table, leaving the first tile accurately positioned at a desired location on panel substrate98. The robot14then returns the end effector60to the tile feeder20to retrieve the next tile in the stack. The table may again be repositioned as needed prior to, during, or after retrieval of the next tile from the tile feeder.

In placing second and subsequent tiles on the panel substrate98, the edges of the previously laid tiles may be advantageously used to help guide the tiles being placed to facilitate a tight assembly. Minimizing the gaps between adjacent tiles may be desirable, for example, when assembling ballistic tiles to form a ballistic armor panel. Referring now toFIG. 18, a second tile412is held by end effector60proximate a panel substrate98on top of which is a previously placed first tile312. End effector60and tile412are shown at a starting position inFIG. 18, where the edge of tile412is offset from the edge of tile312by a small distance “d”, and tile412is spaced above the panel substrate98. Tile412may be entirely above tile312as shown in solid lines, or partially overlapping such that the bottom of tile412is below the top of tile312as shown by dashed lines.

From the starting position ofFIG. 18, tile412is moved into edge contact with tile312as shown inFIG. 19. The end effector may be moved slightly (for example about 0.001 to 0.003 inches) beyond the point of first edge contact to ensure full edge contact between the two tiles, or as close to full contact as possible. The resulting slight interference may be accommodated through compliance of the end effector's grip on tile412, in particular through lateral flexibility of the pins70and bellows74, and by slipping of the tile relative to pins70if needed. With the tile edges in contact, and a slight lateral pressure of tile412against tile312, tile412is moved directly downward into contact with panel substrate98and pressed into place as shown inFIG. 20.

The above described sequence of using a previously placed tile to guide a next tile may be repeated to lay a row of tiles, for example, along an edge of a panel substrate98. For panels that include more than one row of tiles, the same process may be continued, with a minor change to accommodate placing tiles that abut two previously placed tiles instead of one.FIG. 21shows a partially completed panel substrate98already containing a first row120of tiles121through124, and a first tile131of a second row130. Edge125of tile122and edge126of tile131form a corner for receiving the next tile (132) of the second row130. Tile132is shown in an offset starting position, in this case laterally offset from both tiles122and131, and again spaced above the panel like tile412inFIG. 18. From this starting position, tile132may be moved at an approximate 45 degree angle toward the corner formed by tiles122and131, until contacting both tiles, and still spaced above panel substrate98in the manner of tile412inFIG. 19. A compliant pressure may be applied along both contacting edges by again moving the end effector slightly beyond the point of contact on the same angled path. From there the tile is pressed straight down onto the substrate while maintaining the compliant lateral pressure against tiles122and131until the tile is firmly seated on panel substrate98. The end effector may then be released from tile132and sent back to the tile feeder for another tile. The above process can be repeated in any required sequence to complete the second row130, and any additional rows needed for a particular panel. It should further be appreciated that the movable table top82may be repositioned as needed during a panel assembly process, such as between tile rows.

FIG. 22is a schematic representation of an exemplary tile placement machine control system showing the previously mentioned machine and control elements connected by communication and control links420. The PLC28acts as the central master controller, taking user instructions from the HMI30, and coordinating the activities of the machine elements and the other controllers. In the depicted control system embodiment, control instructions are communicated via communication and control links420directly from PLC28to the tile feeders20, and indirectly to table12through one of the machine controllers21. The robots14receive their control instructions directly from machine controllers21.

The control system may further comprise a perimeter encroachment sensor13connected via control link to the PLC28. The encroachment sensor13may incorporate any of various known motion or proximity detection technologies for detecting a physical violation of a prescribed boundary around the tile placement machine. For example, the sensor may be configured to detect a person stepping or leaning across a defined boundary plane marked by a line on the floor around the tool. The PLC28may be programmed to then take a particular action upon receiving a violation signal from the sensor13, such as transmitting a stop signal to the machine and control elements. The PLC may further issue an audio and/or visual alarm to alert the user that a perimeter violation has occurred. The user may then access the HMI30to take appropriate action, such as clearing the alarm, and restarting the tile assembly process. It should be appreciated that the location of the boundary line, and the actions required when a violation occurs may be defined to comply with federal regulations specifically governing operation of automated machinery, namely for example, OSHA Guidelines for Robotic Safety: STD01-12-002-PUB8-1.3; and OSHA 29 CFR 1920 Subpart O, 1910.211 & 212.

User input to the tile placement machine is via the HMI30through a communication/control link420to the PLC28. The HMI30may comprise a control panel160with physical control buttons, and a controllable touch screen162. The control panel160may include control buttons for basic operational functions, such as for example emergency stop (Estop), cycle start, and cycle stop. The controllable touch screen162may be programmed to present a series of screen images with various information displays and control options. For example, one such screen image may provide the ability to select a tile placement pattern from a library of pre-loaded recipes. The same screen or another screen may then present an option for the user to instruct the PLC28to automatically run the selected recipe. This may involve executing a software program for controlling the robots, tile feeders, and movable table in a particular coordinated manner in accordance with the selected recipe.

Selected exemplary touch screen images are shown inFIGS. 24 through 26. Referring initially toFIG. 24, the displayed image includes a graphical representation of the tile placement machine10along with status information and control options. The status information comprises for example status boxes152next to the tile feeders, table drive, robot controllers, and other operable mechanical elements shown on the screen image. Each of boxes152indicates whether the particular mechanical element is ready or not ready for a particular operation to proceed. Status information is also provided by the “Auto Mode”171and “Manual Mode”172on/off boxes located at the bottom left portion of the image ofFIG. 24. Boxes171,172serve as a quick reference to the operator for determining whether the tile placement machine is in automatic or manual operation mode. On the same screen an operator may also select from various control options, such as for example the “Maint” button176at the bottom of the image to perform diagnostics checks on the machine, or the “Alarm Summary” button177to view a history of alarm events. Pushing one of the “Reset To Feed Pos” buttons180will cause the tile feeders on that side to move the tile stacks forward, if needed, to bring the front tile in position to be picked by the robot.

If an automatic tile assembly process is interrupted for any reason, such as by a machine perimeter violation, or activation of the emergency stop, an alert may be displayed on the touch screen. The alert may also include options for continuing or discontinuing the automatic assembly process. For example, shown in the middle of the screen image ofFIG. 25is an alert box164indicating that the emergency stop has been activated by manual operation of the Estop button on control panel160. The alert box164further provides an option for continuing the automatic assembly process from the point where it left off (after manually resetting the Estop button), and an option for canceling the run altogether.

When the control system is in manual operation mode, automatic tile assembly is disabled, while various other manual controls are enabled. The enabled manual controls may allow the operator to perform operations such as for example clearing faults, loading tiles, resetting a tile feeder, and the like.FIG. 26is an example of a touch screen image accessible in manual mode from another screen image, in particular by touching the “Feeders” button175at the bottom of the touch screen image ofFIG. 24. The particular image ofFIG. 26is intended to be used specifically for performing certain manual and semi-automatic operations with the tile feeders. For example, a tile feeder trolley may be manually moved forward, toward the open end of the shoe, or backward, away from the open end of the shoe, by touching either the “Jog Fwd” and “Jog Back” buttons182, and184respectively. Alternatively, a trolley may be moved all the way back to allow for loading a stack of tiles into the shoe by touching the “Position To Load” button186, or reset as described previously using a Reset To Feed Pos button188.

For the purposes of describing and defining the present invention it is noted that the use of relative terms, such as “substantially”, “generally”, “approximately”, and the like, are utilized herein to represent an inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. These terms are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

Exemplary embodiments of the present invention are described above. No element, act, or instruction used in this description should be construed as important, necessary, critical, or essential to the invention unless explicitly described as such. Although only a few of the exemplary embodiments have been described in detail herein, those skilled in the art will readily appreciate that many modifications are possible in these exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the appended claims.

In the claims, any means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. Unless the exact language “means for” (performing a particular function or step) is recited in the claims, a construction under §112, 6th paragraph is not intended. Additionally, it is not intended that the scope of patent protection afforded the present invention be defined by reading into any claim a limitation found herein that does not explicitly appear in the claim itself.