Abstract:
A clamping holder provides both an apparatus and method enabling quick, precise automatic re-positioning of positional devices, particularly useful in edging and milling applications. A clamping holder is capable of automatically approaching, lifting up to surround, engaging and picking up a positioning device, translating to a proper and precise placement location, lowering it into place, disengaging the clamping holder, lowering to provide exit clearance around the positioning device and moving away to either position the next positioning device or to move on to the next task. In addition to this automatic mode, the spindle may also be manually loaded by a worker standing well outside the work area of the main processing machine. A spindle shaped clamping holder has a radial side opening to accept a bearing member and piston support of a locational device. Within the clamping holder is a chamber having a self centering tapered surface to allow the cylindrical shape of the locator bearing member to be exactly centered in the clamping holder when the clamping holder lifts or when the locator downwardly moves within the clamping holder. A single acting, spring opposed, piston clamps down upon the top surface of the cylindrical locator bearing which locks the locator bearing and piston into exact centered alignment with the clamping holder.

Description:
FIELD OF THE INVENTION 
     The present invention relates to improvements in the field of holding devices for machines. More specifically, the present invention relates to a device and method which permits automatic lifting and placement of material locator stops to eliminate the need for workers to enter the dangerous work area of a process machine. 
     BACKGROUND OF THE INVENTION 
     In many instances, it is necessary to locate a position indicating structure with respect to a work piece which is to be milled, sanded, ground, etc. The precision and stability of the positional device is important, as is the ability to re-position the positional device. In computerized machinery, the computer needs to know exactly where the work piece is located in order to precisely operate on the work piece. In older machinery, individual components which either located the work piece, or even which were general supports needed to be bolted down, requiring worker intrusion into the work area. Improvements to the work area enabled the use of a vacuum to hold down work piece supports and locators so that they could be more quickly moved or moved using hooks or poles where necessary from outside of the work area. Where the work pieces are not required to be specifically placed, such as a general support, the use of a pole or other distance manual device allows the worker to remain outside of the work area and push the supports about the table. This is very difficult and increases in difficulty where the general supports have significant weight. Even where a general support is only a few pounds, movement across a table can be difficult. If difficult for use with general supports, the precise locator supports simply cannot be manipulated without the operator getting into the work area of the machine. However, movement of the supports or other structures for specific exact placement are virtually impossible to accomplished by a worker from the edge of a work zone. 
     Even the best method of location, described in issued U.S. Pat. No. 5,562,276, to the inventor herein, discloses the use of an angled device which can be machine located, with a worker placing a vacuum hold down locator against the angled device to insure that the locator is exactly positioned. For this to occur, the worker still must be in a position to visually assure that the locator is precisely located. The vacuum can then be remotely applied to hold the locator down, but where the worker must crawl into the process space each time, the full effectiveness of the use of vacuum hold down during machine set-up is not realizable. 
     The content of U.S. Pat. No. 5,562,276 is incorporated herein by reference. This was a major advance in machine locator technology, since it enabled the locators to be automatically raised to enable location of the work piece, and automatically lowered to enable work to be done on the work piece. However, the human operator was still required to manually go onto the table to make certain that the locator was positioned precisely on the angled device. 
     Currently, and especially in the material grinding industry (including glass, granite, marble and the like), a variety of edge configurations are available, with these complex shapes being ground by a router-type spindle which travels around a work piece. The locator of the U.S. Pat. No. 5,562,276 has a pneumatic operator which rises to enable entry of the work piece to a position tangentially abutting a stop surface of the locator device. After locating the work piece by abutting it against a stop surface of the locator, the stop surface is pneumatically lowered to permit grinding work to be done on the work piece. Where a number of runs of the same type of material generally is to be done, the locators can be left in place, raised as the new material is loaded and the stop surface lowered when the material is being processed. 
     Particularly with machines having larger and more powerful grinding devices and which act upon larger work pieces, the locator devices need to be larger, have larger bases to oppose a tilting force from the work piece as it is being positioned. The need for increased size and more stable work pieces makes physical placement even more onerous. Workers thus spend even more time within the process machinery positioning the material locators, which requires exact location such that the process machinery will register the location of the work piece positioning stop device. 
     In addition, for different runs of different material, re-positioning of the pneumatic locator devices, regardless of size, requires the precise re-positioning of the locator devices. This precise re-positioning takes significant amounts of time. Given the high cost of the process machinery, loss of time and money occurs during change in setup, making the unit cost of a particular run configuration setup quite high. Lowering the time and effort required in changeover will significantly lower the cost of making short runs of material. The ability to make less expensive short runs is valuable, especially where other cost factors in the distribution channel naturally favor short runs, so long as the short runs are of modest additional cost. Thus the cost savings of short run setup ripple through the vertical distribution system. 
     The limitation most encountered in process machinery is the limitation of the main robotic member, typically a spindle or rotational driver having little complex robotic capability. The main capability of the main process member relates to its locational ability, rotational orientation locatability and perhaps one or two other control aspects. In the case of material cutting and polishing machinery, for example, the main robotic member has the ability to select tools, rotationally orient to pick up to rotate to grind and also the ability of a single on and off pressurized air source. The manipulability is thus limited. Utilization of the existing robotic translational capability to the greatest extent possible to eliminate the need for workers to enter the work process space is highly desirable. What is therefore needed is a method and device which will harness the existing robotic ability of the process machine to enable placement of position locators precisely, but without costly additional robotic positioning and manipulation equipment. 
     SUMMARY OF THE INVENTION 
     The devices and systems of the present invention encompasses both an apparatus and method enabling quick, precise automatic re-positioning of positional devices, particularly useful in edging and milling applications. A clamping holder is capable of automatically approaching, lifting up to surround, engaging and picking up a positioning device, translating to a proper and precise placement location, lowering it into place, disengaging the clamping holder, lowering to provide exit clearance around the positioning device and moving away to either position the next positioning device or to move on to the next task. In addition to this automatic mode, the spindle may also be manually loaded by a worker standing well outside the work area of the main processing machine. 
     The working spindle carries a spindle shaped clamping holder having a radial side opening to accept the bearing member and piston support of a locational device. Within the clamping holder is a self centering tapered surface to allow the cylindrical shape of the locator bearing member to be exactly centered in the clamping holder when the clamping holder lifts or when the locator downwardly moves within the clamping holder. A single acting, spring opposed, piston clamps down upon the top surface of the cylindrical locator bearing which locks the locator bearing and piston into exact centered alignment with the clamping holder even where the locating member is asymmetrical or where pneumatic hoses place significant lateral forces on the locator. The locator is then translated, using the main working portion of the process machinery, to an exact location where it is placed on the working surface, and unclamped. The clamping holder is then moved downward so that the cylindrical bearing member of the locating device is within the radially located clearance space, and the clamping holder along with the main working portion of the process machinery is moved away from the locator. The clamping holder may be vacuum operated so that it may be fixed solidly to the working surface as soon as it is placed downwardly upon the working table, otherwise the vacuum placement may occur after the clamping holder has moved away from the positioning device. This enables selective remote vacuum fixation to realize its full potential by keeping workers out of the work space, and able to selectively affect placement and vacuum lock down of the positioning devices remotely. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention, its configuration, construction, and operation will be best further described in the following detailed description, taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a prior art drawing showing a machine operator placing a vacuum locator using an angled block suspended from a working spindle in a glass grinding machine; 
     FIG. 2 is a perspective view of a clamping holder of the present invention approaching a cylindrical upper bearing member and piston of a work piece positioning device; 
     FIG. 3 is a perspective of the completion of the approach of FIG. 2 in which the cylindrical upper bearing member is captured within an upper chamber of the clamping holder; 
     FIG. 4 is a partially exploded view of the clamping holder of the invention separated from a conic tool holder and showing details of the attachment to the conic tool holder; 
     FIG. 5 is a completely exploded view showing the illustrative component parts of the clamping holder of the invention; 
     FIG. 6 is a side sectional view with greater detail of the inside of the clamping holder and shown in a position having just captured the cylindrical upper bearing member of a work piece positioning device; and 
     FIG. 7 is a view in accord with FIG. 6 but where the piston is actuated downward and where the cylindrical upper bearing member of a work piece positioning device is forced into its frusto-conical centering lower chamber and where the work piece positioning device is centered with respect to the clamping holder. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The description and operation of the invention will be best described with reference to prior art FIG. 1, which is a perspective view of a process machine worker manually positioning a locator which was described in the U.S. Pat. No. 5,562,276. From the top, a motor unit  11 , drawn in phantom, engages a conic tool holder  13  which is used to engage a compatible device at the driving end of the motor unit  11 . The conic tool holder  13  has registering notches  15  at opposite sides thereof so that the position of any tool to which it is connected can be registered or keyed to the exact rotational position, typically accomplished by maintaining a constant starting position when taking a tool from a tool rack or by computer input rotational command at a desired moment during the positioning cycle. The conic tool holder  13  shown has 180° rotational symmetry (some tool holders are asymmetrical) and is illustrated to emphasize the need for obtaining an exact angular registration, even where the conic tool holder  13  has such 180° symmetry. 
     The motor unit  11  is typically located on a motion control device which has the ability to move the motor unit  11  in three dimensions within a defined works space over a table. The location method of FIG. 1 involves the use of an angled locator block  17  being connected to the conic tool holder  13  and with the motor unit  11  being commanded to move to a location where a positional device  19  is to be situated. The angled locator block  17  has a pair of angled surfaces  21  into which an upper bearing member  23  must be exactly positioned, by hand. Once the motor unit  11  has achieved the correct location and height, a worker must crawl into the machine space and manually push the positional device  19  into place with respect to the angled locator block  17 . 
     Once the positional device  19  is located, the worker must crawl out of the work space, and command the motor unit  11  to move to the next location into which the next positional device  19  is to be located. The motor unit  11  must move away from the positional device  19 , and is normally raised up rather than attempting to move laterally away since it usually has no angular registration. Raising it avoids tipping the positional device  19  over or moving it forcibly about the table. 
     The positional device  19  carries a base  25  which may be extremely eccentrically mounted with respect to a base housing  27 . A pair of nested piston structures includes an outer piston member  29  and an inner piston member  31  so that the positional device  19  will be able to drop the cylindrical upper bearing member  23  as far down from its maximum height as possible to allow maximum working area for the process operations after setup is achieved. Other features seen on the positional device  19  include a lower pneumatic fitting  33  and an upper pneumatic fitting on the base housing  27 , which operate the outer and inner piston members  29  and  31  to an up or down position depending upon which of the fittings  33  and  35  are pressurized. A fitting  37  is located on the base  25  which is used to independently apply vacuum to enable the base  25  and thus the entire positional device  19  to be fixed firmly on any flat working surface within the work area. The vacuum controls are most advantageously located off the working area, and in the configuration of FIG. 1, a worker  39 , whose hand is seen in FIG. 1, cannot take full advantage of the remotely located vacuum controls. Any time the worker  39  has to locate himself within the work area, no matter what degree of safety interlocks are applied to the controls, an inherent unsafe condition exists. 
     All of the fittings  33 ,  35 , and  37  are expected to have quick release connectors at the open end shown to facilitate rapid connection and disconnection of air supply and vacuum supply hoses. Other details of the conic tool holder  13  include an upper land  41  useful for being grasped and manipulated by the motor unit  11 . At the center of the land  41  is an air entry port  43  with which the conic tool holder  13  makes air available, if possibly utilizable by any tool which the conic tool holder  13  was interconnected. In the case of machines for cutting and polishing glass, stone, granite and the like, the port  43  is used to supply pressurized air, or liquid coolant, in an on and off or pressurized and non-pressurized state to enable further actuatable control of any tool secured to the conic tool holder  13 . The pressurized air input can be used for other purposes, such as clearing the line between tool changes. 
     Referring to FIG. 2, a clamping holder  51  is shown in place underneath a conic tool holder  13 , the details of the attachment of the clamping holder  51  to the conic tool holder  13  shown later. Clamping holder  51  has a first end abutting the conic tool holder  13  and presenting an almost continuous exterior profile. Clamping holder  51  has a first plate  53  at its first end. Below the first plate  53  are a series of connecting pillars  55  which surround a piston chamber annular ring  57 . Both the lower ends of the pillars  55  and bottom of the piston chamber annular ring  57  contact a second plate  59 . The pillars  55  join the first plate  53  to the second late  59  and sandwich the piston chamber annular ring  57  therebetween. 
     Below the second plate  59  is an upper chamber plate  61 . Upper chamber plate  61  carries an opening referred to as upper opening  63  which extends toward the center of the upper chamber plate and is the width of the upper chamber  65 . Below the upper chamber plate  61  is a lower chamber plate  67  having a lateral opening  69  which is narrower than the maximum width of the upper opening  63 , and having an internal lower chamber  70  the purpose being to capture a cylindrical upper bearing member  71  of a work piece positioning device  73 . 
     The positioning device  73  has a base  75 , and a heavy duty piston actuator housing  77 . Base  75  may be actuated to a stable position through the use of a vacuum or magnets, or the entire base of positioning device  73  may be made of magnetic material, or the base of positioning device  73  may be an electromagnet. Fittings  79  operate the lowering and raising of a piston rod  81 . Fitting  83  can be used where the base  75  is a vacuum base with a sealing ring, to accept a vacuum hose to deliver a vacuum supply to the positioning device  73 . Where the base  75  supports an electromagnet, the fitting  83  can be used to run wires to power the electromagnet. In this configuration, the same fitting  83  can be used for both. In cases where the base  75  is itself a permanent magnet, the fitting  83  may be eliminated entirely. Whether magnetic or vacuum or other holding force, there must be enough downward force to oppose the loading of work pieces into the work area. 
     The motor unit  11  may approach a positioning device  73  with its piston rod  81  fully extended, at a level, and from a direction relative to the rotation of the clamping holder  51  which will orient the lateral opening of the combined openings  69  and  63  to capture the upper bearing member  71  and piston rod  81  within the upper chamber  63  and an upper portion of the lower chamber  70 . Care must be used when using a 180° rotational symmetry holder such as conic tool holder  15  to insure that the clamping holder  51  achieves the exact rotational orientation. Also seen in FIG. 2 is a clamping disk  85  which will be used to apply downward force to, and abut the top of the cylindrical upper bearing member  71 , to insure that the cylindrical upper bearing member  71  is securely locked within the clamping holder  51 . 
     The initial position of capture is shown in FIG.  3 . In FIG. 3, the cylindrical upper bearing member  71  resides within the upper chamber  65  and upper portion of the lower chamber  70 , but ideally will not touch any of the internal walls of the clamping holder  51 . To complete the capture, two other steps need to occur, and they may occur in any order as needed. First, the clamping holder  51  will need to be lifted upwardly to cause the cylindrical upper bearing member  71  to move down into the lower most extent of the lower chamber  70 . Lower chamber  70  is frusto-conically shaped with a sectionally appearing tapered surface which automatically centers the cylindrical upper bearing member  71  with respect to the center line of the clamping holder  51 . Secondly, the clamping disk  85  is brought down to bear on the top of the cylindrical upper bearing member  71  to insure that cylindrical upper bearing member  71  stays locked into place at the bottom of the lower chamber  70  and cannot move in any direction with respect to the clamping holder  51 . Thereafter, the motor  11 , conic tool holder  13  and clamping holder  51  can continue to lift the work piece positioning device  73  to any other position on the work table. 
     This procedure is especially useful where the computer controller for the motor unit  11  is electronically aware of the position of the work piece positioning device  73 , as well as the fact that the piston  81  is in fully extended position. In instances where the main process machine is being set up initially, it is much easier to bring the motor unit  11  to the front of the work space, with the clamping holder  51  in an elevated position, and simply have a worker manually enter the cylindrical upper bearing member  71  of the work piece positioning device  73  into the clamping holder  51 . In this case, the only additional step is to actuate the clamping disk  85  to hold the clamping holder  51  solidly in place and then have the motor unit  11  move the clamping holder  51  to an exact position desired and then decouple. This can be done with a series of simple and programmable computer input codes. 
     The decoupling procedure has one or two more subtleties which relate to downward placement of the clamping holder. Preferably, and as will be shown, the clamping disk  85  will be pneumatically actuated through pressure applied to the air entry port  43  and thus the force applied to the clamping disk  85  will be subject to compression depending upon the pressure at air entry port  43 . While the unit is being placed down, it is preferable that air be introduced through one of the fittings  79  which is connected to extend the piston  81  to insure that the piston  81  remains fully extended during the downward implacement operation. This also gives a degree of spring in the piston  81 . Preferably, the upward force on the piston  81  should be greater than the downward force on the clamping disk  85 , but in any case, the downward motion of the motor unit  11  and contact of the work piece positioning device  73  will be cushioned by the pneumatic forces against clamping disk  85  and piston  81 . This prevents the motor unit  11  from driving the work piece positioning device  73  through the table if the tollerancing capability of the motion controller exceeds its clearance. In addition, the clamping holder  51  of the present invention gives another capability, that of pressing the work piece positioning device  73  down onto the table just before a vacuum is applied to the fitting  83 , or before the electromagnet in the base  75  is actuated through current applied to an electromagnet. In fact, the holding force through either vacuum or magnet can be applied during the time the motor unit  11  is exerting downward force on the clamping holder  51  so as to insure that the work piece positioning device  73  stays exactly where it is placed. This insures the ability to retrieve it later on. 
     Once the holding force through vacuum or magnet is applied (if it is applied), the clamping disk  85  is lifted to provide clearance in the upper chamber  65  for the cylindrical upper bearing member  71  to move upwardly within it, and then escape from the upper opening  63 . During this time, the pneumatic pressure urging piston  81  to the fully extended position should be continued. The motor unit  11  is then lowered, lowering the clamping holder  51  to a level where the upper chamber  65  surrounds the cylindrical upper bearing member  71 , and the upper opening  63  is before cylindrical upper bearing member  71 . The motor unit  11  and the clamping holder  51  then move in a direction away from upper opening  63  to enable cylindrical upper bearing member  71  to move evenly through the center of the upper opening until the clamping holder has moved away from the cylindrical upper bearing member  71  and work piece positioning device  73 , thus completing the placement of the work piece positioning device  73 . In cases where a permanent magnet base  75  is used, the deactivation of the holding force is not necessary so long as the motor unit  11  has enough force and power to lift the work piece positioning device  73 . 
     Referring to FIG. 4, a view of the clamping holder  51  apart from the conic tool holder  13  shows details of connection. The inlet air port  43  communicates with an inlet air port  91  of a threaded boss  93  which is preferably continuous with the first plate  53 . On the boss  93 , an upper set of threads  95  overlies a conical locating surface  97  which is used to center the clamping holder  51  with respect to the conic tool holder  13 . Preferably a locking device is used to precisely set the rotational relationship of the clamping holder  51  with respect to the conic tool holder  13  to insure that precision in rotational position of the conic tool holder  13  will translate to the clamping holder  51 . Since the forces between the clamping holder  51  and the conic tool holder  13  should occur at the conical locating surface  97 , a soft rubber gasket  99  is provided to seal out any debris which might fall atop an upper surface  101  of first plate  53 . 
     Also seen atop the upper surface  101  is a series of threaded screws  103  which lie just inside a very shallow lip  105 . The screws extend through the connecting pillars and into the second plate  59  to hold the upper portion of the clamping holder  51  together. Atop the second plate  59 , a bolt head  107  is seen which is used to secure the second plate to the lower chamber plate  67  and sandwich the upper chamber plate  61  therebetween. 
     Further details of the clamping holder  51  are seen including the lateral opening  69  and its continuity to form a lower opening  109 , as well as a lower beveled surface  111 . 
     Referring to FIG. 5, an exploded view of the clamping holder illustrates further details of construction. From the top, the threaded screws  103  can be seen passing through upper bores  113 . Below the first plate  53 , an abbreviated axial length piston  121  is seen surrounded by an “o” ring  123  which is held in a radially outwardly disposed groove (not directly seen in FIG.  5 ). The piston  121  is connected to a piston rod  125 . The piston rod  125  fits through a coil spring  127  to enable the piston  121  to operate as a single side single action piston with actuating force coming through air pressure from above and return force coming through spring action bearing from below. Piston chamber annular ring  57  is provided for the piston  121  to act within, to contain spring  127 , and to keep debris out of the internal assembly. 
     Four of the connecting pillars  55  can be seen and which act to stabilize and space apart the first and second plates  53  and  59 . The threaded screws  103  extend through bores  129  in the pillars  55  to then engage threaded apertures  131  into the top of second plate  59 . Through bores  133  in second plate  59  accommodate the bolts  107 . Through bores  133  align with through bores  135  of the upper chamber plate  61 . The through bores  135  of the upper chamber plate  61  align with threaded bores  137  in the lower chamber plate  67 . This sandwiches the upper chamber plate  61  between the second plate  59  and the lower chamber plate  67 . 
     In the lower chamber plate  67 , the lower chamber  70  has a tapered wall  141  on the side, bounded by a radial groove  143 . The radial groove bears against the lower surface of the periphery of the cylindrical upper bearing member  71  of the work piece positioning device  73 . 
     Also seen is an exhaust port  145  communicates through a point within the piston chamber annular ring  57 , to enable air to breathe in and out of the space below the piston  121 . Also seen is a threaded screw  151  which secures the clamping disk  85  to the bottom of piston rod  125 . The bottom of piston rod  125  contains a threaded bore (not seen) to securely attach the clamping disk  85  to the piston rod  125 . 
     Referring to sectional FIGS. 6 and 7 further details are seen, and the action within the clamping holder  51  is illustrated. From the top, conical tool holder  13  has an internally threaded surface  161  which engages thread  95 . The piston chamber annular ring  57  is sealed with respect to first plate  53  by a first outer “o” ring  163 , and sealed with respect to second plate  59  by a second outer “o” ring  165 . The spring  127  is shown in the extended position with piston  121  at its upper position and cylindrical upper bearing member  71  having been just captured by the clamping holder  51 , in a position as seen in FIG.  4 . 
     Referring to FIG. 7, the spring  127  is shown in the compressed position with piston  121  at its lower position after the introduction of pressurized air into the inlet air port  91  which pushes piston  121  down. Cylindrical upper bearing member  71  is now forced by the clamping disk  85  into the lower chamber  70  having tapering side walls  141  which force the member  71 , and its work piece positioning device  73  to be centered exactly with respect to the clamping member  51 . Since the motion control machinery may produce forces greater than the forced produced by pneumatic pressure in either the clamping member  51  or the positioning device  73 , it is desirable for the downward pressure on the piston  121  to be applied while the motor unit  11  is raised so that the movements may be more fluid and precisely assured. 
     One consideration which should be addressed is the radial registration of the clamping holder  51  to the conic tool holder  13 . This can be accomplished by several methods. In one, the threaded connection between the clamping holder  51  and the conic tool holder  13  is simply tightened to the maximum extent, and then the radial position of the openings  69  and  93  is simply registered with the controls for the process machinery which directs motor unit  11  about the work area. Another way is to provide a locking structure which can be aligned and engaged after sufficient force has been brought to bear on the conical locating surface  97 . In addition to registering the radial position of the openings  69  and  93 , the locking mechanism would prevent any detachment between the clamping holder  51  and the conic tool holder  13 , although with such insignificant torque in the operation of the clamping holder  51 , disengagement is not expected to be a problem. Other mechanisms could be used to split the first plate into two plates, an upper first plate to be highly torqued to the conic tool holder  13  and a lower first plate to be registered with set screws or the like to the upper first plate. Other mechanism are possible, and too numerous to adequately treat here. 
     While the present invention has been described in terms of a device and system used in conjunction with all types of process machinery, and in particular with machinery for the milling, edging and machining of materials including glass, granite, marble, stone, and the like, one skilled in the art will realize that the structure and techniques of the present invention can be applied to many appliances. The present invention may be applied in any situation where the position of components are desired to be precisely located and to avoid operators having to enter the work process area of a manufacturing system to increase safety, and to reduce lost time. 
     Although the invention has been derived with reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. Therefore, included within the patent warranted hereon are all such changes and modifications as may reasonably and properly be included within the scope of this contribution to the art.