Abstract:
The present invention provides a device for controlling a hand wheel of a machine tool and a method for using the same.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to machine tools. More particularly, the present invention relates to a device for controlling a hand wheel of a machine tool and to a method for using the same. 
         [0003]    2. Description of the Related Art 
         [0004]    Computer numerically controlled (“CNC”) machine tools use various cutting tools, such as drills, end mills, reamers, and taps, to manufacture a workpiece into a final part. The cutting tools are held by a movable, rotating spindle under the control of a part program to selectively contact the workpiece and remove material from the workpiece. The result is a manufactured part having a desired shape. 
         [0005]    The machine tool itself may be provided with a control system for automatically positioning the workpiece and the cutting tool. For example, the control system may include a computer software program for automatically operating the machine tool. Machine tools may also be provided with devices for manually positioning the workpiece and the cutting tool. For example, the machine tool may include a hand wheel. A user may rotate the hand wheel to indicate a desired motion, position, and/or velocity of the machine tool. 
         [0006]    Currently, when a user manually positions the workpiece and/or the cutting tool using the hand wheel, the machine tool receives information from the hand wheel using an optical glass code system. The system includes a glass code wheel, an LED, and an optical detector. The glass code wheel has etched portions that block light from the LED from passing through to the optical detector and clear portions that permit light from the LED to pass through to the optical detector. The glass code wheel must be precisely machined and etched, and the optical detector must be precisely aligned with the glass code wheel. Additionally, the glass code system may require dedicated software to interpret signals from the optical detector. 
       SUMMARY 
       [0007]    According to an embodiment of the present invention, a machine tool is provided having at least one movable element, a control system, a rotatable hand wheel, and a pointing device. The pointing device is coupled to the hand wheel. The pointing device is configured to track a movement of the hand wheel and communicate the movement to the control system. The control system is configured to control the at least one movable element based upon the movement of the hand wheel. 
         [0008]    According to another embodiment of the present invention, a device is provided for manually operating a machine tool. The device includes a rotatable hand wheel and a pointing device. The pointing device is coupled to the hand wheel. The pointing device is configured to track and communicate a movement of the hand wheel. 
         [0009]    According to yet another embodiment of the present invention, a method is provided for manually operating a machine tool. The method includes the steps of providing a hand wheel with a pointing device coupled to the hand wheel and rotating the hand wheel. The method further includes the steps of tracking a movement of the hand wheel with the pointing device, communicating the movement of the hand wheel to a control system, and positioning a movable element of the machine tool based upon the movement of the hand wheel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0011]      FIG. 1  is a schematic diagram illustrating a method of the present invention for using a pointing device to track movement of a hand wheel of a machine tool; 
           [0012]      FIG. 2  is an elevational view of the pointing device coupled to the hand wheel according to an embodiment of the present invention; 
           [0013]      FIG. 3  is a view similar to  FIG. 2  of the pointing device coupled to the hand wheel according to another embodiment of the present invention; 
           [0014]      FIG. 4  is a bottom plan view of the pointing device coupled to the hand wheel according to an embodiment of the present invention; 
           [0015]      FIG. 5  is a view similar to  FIG. 4  of the pointing device coupled to the hand wheel according to another embodiment of the present invention; and 
           [0016]      FIG. 6  is a view similar to  FIG. 4  of the pointing device coupled to multiple hand wheels according to an embodiment of the present invention. 
       
    
    
       [0017]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION 
       [0018]    The embodiments disclosed below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings. 
         [0019]    Referring to  FIG. 1 , machine tool  10  is provided for manufacturing a workpiece. Machine tool  10  may include, for example, a milling machine, a lathe, or a drilling machine. Machine tool  10  includes cutting tool  12  held by a movable, rotating spindle. In operation, cutting tool  12  of machine tool  10  selectively contacts the workpiece (not shown) under the direction of a part program and removes material from the workpiece, resulting in a manufactured part having a desired shape. For example, cutting tool  12  may be in the form of a drill bit, an end mill, a reamer, or a tap. 
         [0020]    Referring still to  FIG. 1 , machine tool  10  includes at least one movable element  14 . Movable element  14  may include, for example, cutting tool  12 , tool magazine  13 , and/or a workpiece positioning or handling mechanism such as workpiece table  16 . As previously mentioned, cutting tool  12  contacts the workpiece to remove material from the workpiece. Tool magazine  13  is configured to store numerous cutting tools  12 . Workpiece table  16  is configured to fix the workpiece in place and to move the workpiece relative to cuffing tool  12 . As movable element  14  changes position, the relative position between cutting tool  12  and the workpiece also changes. For example, cutting tool  12  may be raised and lowered (Z direction) relative to the workpiece and tool magazine  13  may be rotated. Similarly, workpiece table  16 , and the workpiece attached thereto, may be moved side to side (X direction), moved back and forth (Y direction), and raised and lowered (Z direction) relative to cutting tool  12 . Workpiece table  16  may also include a rotary table that rotates the workpiece relative to cutting tool  12 . 
         [0021]    Referring still to  FIG. 1 , machine tool  10  further includes control system  18 . Control system  18  may be configured to receive user inputs, to execute a part program, and/or to control movement of movable element  14 . Control system  18  may include a personal computer having a software program for operating machine tool  10  and for executing a part program, such as a computer numerically controlled (CNC) software program. 
         [0022]    Referring to  FIGS. 1-3 , machine tool  10  further includes hand wheel  20 . Hand wheel  20  may be rotated by a user. In operation, the user rotates hand wheel  20  to direct movable element  14  to move or to change the velocity of movable element  14 . The user may manually direct movable element  14  to move or change velocity during set-up and positioning of machine tool  10  and/or during operation of machine tool  10 . For example, during operation of machine tool  10  by a part program, the user may modify the velocity of movable element  14 . Hand wheel  20  may include handle  22  to assist the user in gripping and rotating hand wheel  20 . Hand wheel  20  may further include detent mechanism  24 , illustrated in  FIG. 2 . Detent mechanism  24  is configured to hold the rotational position of hand wheel  20  in place, to provide tactile feedback to the user, and to provide consistent and repeatable rotational increments resulting in consistent and repeatable movements of movable element  14 . Hand wheel  20  may also include markings to indicate its rotational position. 
         [0023]    To communicate movement of hand wheel  20  to control system  18 , pointing device  26  is provided, as illustrated in  FIGS. 1-3 . Pointing device  26  includes any device capable of tracking a moving surface, referred to herein as tracking surface  28 , and communicating the tracked movement to control system  18 . More specifically, pointing device  26  may include sensor  30  capable of tracking movement of tracking surface  28  and output  32  capable of communicating the tracked movement to control system  18 . Tracking surface  28  need not include any special features for pointing device  26  to operate properly. For example, tracking surface  28  need not include patterns, slots, or holes. In fact, the Twin-Eye Laser Sensor available from Philips Electronics of the Netherlands may be capable of tracking a mirrored tracking surface  28 . Pointing device  26  may further include enclosure  33  to surround, shield, and protect sensor  30 . 
         [0024]    In an exemplary embodiment of the present invention, pointing device  26  includes a computer mouse or the working components of a computer mouse. More specifically, pointing device  26  may include a roller-ball mouse, a track ball mouse, an optical mouse, a laser mouse, or any other type of computer mouse. Rather than moving pointing device  26  relative to a stationary tracking surface  28 , such as a desk or mouse pad, tracking surface  28  itself may move relative to a stationary pointing device  26 . Alternatively, pointing device  26  may function as it normally would by moving pointing device  26  relative to tracking surface  28 . 
         [0025]    Sensor  30  of pointing device  26  is capable of detecting motion of tracking surface  28  in at least one dimension. Sensor  30  may also be capable of both emitting and detecting signals, or a separate component may be provided for emitting signals that sensor  30  detects. For example, if pointing device  26  includes an optical computer mouse, pointing device  26  may include a light-emitting diode (LED) that emits light onto tracking surface  28 , and sensor  30  may be capable of sensing light reflected by tracking surface  28 . As another example, if pointing device  26  includes a laser computer mouse, pointing device  26  may include an infrared laser diode that emits light onto tracking surface  28 , and sensor  30  may be capable of sensing light reflected by tracking surface  28 . An exemplary sensor  30  is relatively tolerant of various physical arrangements of pointing device  26  and tracking surface  28 , including variations in distance between the components. Further, the precision of an exemplary sensor  30  may be altered via a command from control system  18  to accommodate these various physical arrangements. For example, the sensitivity of sensor  30  may be altered to vary the apparent speed of tracking surface  28  without having to modify the physical arrangement itself. 
         [0026]    Output  32  of pointing device  26  is capable of communicating with control system  18 , such as a personal computer. For example, output  32  may include a universal serial bus (USB) connector, a PS/2 connector, a serial port connector, or another known connector. Control system  18  may include a port configured to receive output  32  of pointing device  26 . For example, control system  18  may include a USB port, a PS/2 port, a serial port, or another suitable port. 
         [0027]    Referring to  FIGS. 2-3 , to track movement of hand wheel  20 , pointing device  26  is coupled to hand wheel  20  such that pointing device  26  tracks movement of rotating hand wheel  20 . In one embodiment of the present invention, illustrated in  FIG. 2 , pointing device  26  is coupled to hand wheel  20  such that tracking surface  28  is a surface of hand wheel  20  itself. More specifically, tracking surface  28  is the bottom surface of hand wheel  20 . In another embodiment of the present invention, illustrated in  FIG. 3 , hand wheel  20  is coupled to disc  34 , which is in turn coupled to hand wheel  20  to rotate with hand wheel  20 , such that tracking surface  28  is a surface of disc  34 . More specifically, tracking surface  28  is the bottom surface of disc  34 . As shown, both hand wheel  20  and disc  34  are mounted to rotating shaft  36  to rotate therewith. 
         [0028]    As mentioned above, pointing device  26  may include enclosure  33  to surround, shield, and protect sensor  30 . For example, enclosure  33  may be used to prevent stray electromagnetic interference from disrupting operation of sensor  30 . In one form of the present invention, both pointing device  26  and tracking surface  28  are located within enclosure  33 . In another form of the present invention, pointing device  26  and tracking surface  28  are located within separate enclosures, especially when less-stringent optical tolerances are necessary. In other words, pointing device  26  may be located within enclosure  33 , while tracking surface  28  may be located within a separate enclosure. Each separate enclosure may have a unique ingress protection (IP)/NEMA rating. In yet another form of the present invention, illustrated in  FIGS. 2-3 , tracking surface  28  need not be enclosed. The enclosures described herein may be transparent or opaque. 
         [0029]    Referring to  FIG. 4 , pointing device  26  may be configured to track movement of tracking surface  28  in one dimension. As hand wheel  20  or disc  34  coupled thereto ( FIG. 3 ) rotates in the direction illustrated schematically by arrow  38 , pointing device  26  remains stationary relative to hand wheel  20  or disc  34  coupled thereto ( FIG. 3 ). In this position, pointing device  26  tracks movement of tracking surface  28  along a single axis, illustrated schematically as X axis  40 . If pointing device  26  is capable of tracking movement in more than one dimension, control system  18  may be configured to receive inputs relating to the one dimension and to ignore inputs relating to other dimensions. 
         [0030]    Referring to  FIG. 5 , pointing device  26  may track movement of tracking surface  28  in more than one dimension. As hand wheel  20  or disc  34  coupled thereto ( FIG. 3 ) rotates in the direction illustrated schematically by arrow  38 , pointing device  26  remains stationary relative to hand wheel  20  or disc  34  coupled thereto ( FIG. 3 ). In this position, pointing device  26  tracks movement of tracking surface  28  along multiple axes, illustrated schematically as X axis  40  and Y axis  42 . In an exemplary embodiment, sensor  30  of pointing device  26  may be oriented 45 degrees from tangent  44 . In this position, the movement of tracking surface  28  along X axis  40  is equivalent to the movement of tracking surface  28  along Y axis  42 . Pointing device  26  may track movement of tracking surface  28  along both X axis  40  and Y axis  42  for redundancy, to assist in determining if sensor  30  is reporting false movement. Also, pointing device  26  may track movement of tracking surface  28  along both X axis  40  and Y axis  42  while providing separate configurations for each dimension. Each dimension of pointing device  26  may be independently programmed to track tracking surface  28  with unique speed sensitivity, resolution, laser intensity, and/or surface conditions. For example, pointing device  26  may be programmed to track movement of tracking surface  28  along X axis  40  with a low speed sensitivity to allow the system to reject slight, unintended movements of hand wheel  20 , such as movements caused by vibration or minor bumping. At the same time, pointing device  26  may be programmed to track movement of tracking surface  28  along Y axis  42  with a high speed sensitivity to allow the system to respond to intentional movements of hand wheel  20 . 
         [0031]    Referring to  FIG. 6 , pointing device  26  may track the movement of more than one hand wheel, referred to herein as first hand wheel  20   a  and second hand wheel  20   b . As first hand wheel  20   a  rotates in the direction illustrated schematically by first arrow  38   a , pointing device  26  tracks movement of tracking surface  28  along X axis  40 . In the illustrated arrangement, tracking surface  28  of first hand wheel  20   a  is essentially stationary along Y axis  42  with essentially all of the rotational movement occurring along X axis  40 . To this point, pointing device  26  of  FIG. 6  performs essentially the same as pointing device  26  of  FIG. 4 . Second hand wheel  20   b  may also be provided. Rather than remaining stationary relative to first hand wheel  20   a , pointing device  26  moves radially relative to first hand wheel  20   a . As shown, pointing device  26  is coupled to second hand wheel  20   b . More specifically, pointing device  26  is coupled to rack  46  that interacts with gear or pinion  48  coupled to second hand wheel  20   b . The illustrated embodiment is not intended to limit the scope of the present invention as pointing device  26  may be coupled to second hand wheel  20   b  in other ways, such as with a worm gear or a pulley system. As second hand wheel  20   b  rotates in the direction illustrated schematically by second arrow  38   b , pointing device  26  travels over tracking surface  28  along Y axis  42  and tracks its movement over tracking surface  28 . As mentioned above, tracking surface  28  of first hand wheel  20   a  is essentially stationary along Y axis  42 , such that the tracked movement along Y axis  42  may be attributed to second hand wheel  20   b . As mentioned above, pointing device  26  may be programmed with separate configurations in each dimension to track first hand wheel  20   a  and second hand wheel  20   b  with, for example, unique speed sensitivity, resolution, laser intensity, and/or surface conditions. For example, pointing device  26  may be programmed to track movement of tracking surface  28  along X axis  40  with a low speed sensitivity to allow the system to reject slight, unintended movements of first hand wheel  20   a , such as movements caused by vibration or minor bumping. At the same time, pointing device  26  may be programmed to track movement of tracking surface  28  along Y axis  42  with a high speed sensitivity to allow the system to respond to intentional movements of second hand wheel  20   b . In an alternative embodiment of the present invention, both first hand wheel  20   a  and second hand wheel  20   b  may be provided with separate pointing devices  26 . 
         [0032]    Referring again to  FIG. 1 , pointing device  26  is capable of communicating the tracked movement of tracking surface  28  to control system  18 . In an exemplary embodiment of the present invention, output  32  of pointing device  26  may communicate incremental plus (+)/minus (−) signals, or data packets containing that information, to control system  18 . For example, as shown in  FIG. 4 , as hand wheel  20  rotates in a clockwise direction, sensor  30  of pointing device  26  tracks rightward movement of tracking surface  28  along X axis  40  and communicates corresponding plus (+) signals to a CPU within pointing device  26 . The number of plus (+) signals communicated to the CPU indicates the distance tracked by pointing device  26 . In other words, sensor  30  will send more plus (+) signals to the CPU when the user rotates hand wheel  20  quickly than when the user rotates hand wheel  20  slowly. Over an allotted time increment (e.g. 0.005-0.01 second), the CPU of pointing device  26  will count the signals and convert the signals to a data packet indicating the distance tracked over the allotted time increment. Output  32  of pointing device  26  will incrementally communicate data packets to control system  18 . Similarly, as hand wheel  20  rotates in a counter-clockwise direction, sensor  30  of pointing device  26  tracks leftward movement of tracking surface  28  along X axis  40  and communicates corresponding minus (−) signals to the CPU of pointing device  26 . The CPU then communicates data packets indicating the tracked distance to control system  18 . It is also within the scope of the present invention that rightward movement of tracking surface  28  along X axis  40  may generate a minus (−) signal rather than a plus (+) signal and that leftward movement of tracking surface  28  along X axis  40  may generate a plus (+) signal rather than a minus (−) signal. 
         [0033]    Referring still to  FIG. 1 , control system  18  is configured to receive communications from pointing device  26 . As described above, control system  18  may receive incremental data packets indicating the tracked distance from output  32  of pointing device  26 . These data packets may be associated with an electronic signature that directs the data packets to, for example, a CNC software program, rather than to an icon on a screen in a conventional manner. In this manner, control system  18  may include a separate computer mouse that controls the screen icon in the conventional manner. In operation, control system  18  interprets the data packets and then directs movement of movable element  14  accordingly. Returning to the previous example illustrated in  FIG. 4 , if a user rotates hand wheel  20  in a clockwise direction, sensor  30  of pointing device  26  communicates plus (+) signals to the CPU within pointing device  26 , and then the CPU communicates data packets indicating the tracked distance to control system  18 . Upon receiving these data packets, control system  18  directs movable element  14 , such as cutting tool  12 , tool magazine  13 , or workpiece table  16 , to move or to change velocity. For example, control system  18  may direct cutting tool  12  upward (Z direction) relative to the workpiece. The resulting motion of movable element  14  may correspond to the distance and/or speed at which the user rotated hand wheel  20 . 
         [0034]    In addition to determining incremental rotational movement of hand wheel  20 , control system  18  may determine and store the absolute rotational position of hand wheel  20 . The absolute rotational position of hand wheel  20  may be stored in non-volatile memory of control system  18 , such that the absolute rotational position is reset when control system  18  is restarted. The absolute rotational position of hand wheel  20  may also be displayed for the user. For example, the absolute rotational position of hand wheel  20  may be displayed digitally on hand wheel  20  or on a nearby computer screen of control system  18 . 
         [0035]    While this invention has been described as having preferred designs, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.