Abstract:
A tool for depositing material onto a three-dimensional surface comprises a first tubular member comprising a first guide surface and a second guide surface. The tool further comprises a second tubular member comprising a first guide surface engaging the first tubular member first surface and comprising a second guide surface engaging the first tubular member second surface. A first resilient member is disposed to urge the second tubular member in a first axial direction relative to the first tubular member. A tubular material holder is disposed axially within the second tubular member. A second resilient member is disposed in the tool to urge the holder in a second axial direction opposite to said first axial direction.

Description:
FIELD OF THE INVENTION 
     The invention pertains to a tool for operating on three-dimensional surfaces, in general, and a tool to mark lines in the manufacture of cranial remodeling devices, in particular. 
     BACKGROUND OF THE INVENTION 
     Cranial remodeling is utilized to correct for deformities in the head shapes of infants. Prior to the development of the Dynamic Orthotic Cranioplasty SM  method of cranial remodeling by Cranial Technologies, Inc, the assignee of the present invention, the only viable approach for correction of cranial deformities was surgical correction of the shape of the cranium. Dynamic Orthotic Cranioplasty SM  utilizes a treatment protocol in which the DOC BAND® cranial remodeling device is custom produced for each subject to be treated. 
     In the past, custom cranial remodeling devices were produced by first obtaining a full size and accurate cast of the actual head shape of each subject. This cast was then modified to produce a second or desired head shape model. The second or desired head shape model is used to form the cranial remodeling band for the infant. In the past, the second or desired shaped head shape model was obtained by manually modifying the first cast to form the desired shape model. 
     Cranial Technologies has maintained a “library” of the casts of the head casts of infant&#39;s deformed heads and the corresponding models of the desired corrected head shapes. 
     Cranial Technologies, Inc. continued its pioneering developments with its proprietary DSI® digital image capturing system and its Digital Surface Imaging®methodology for the time efficient and safe image capture of three-dimensional full head images. 
     More specifically, the DSI® digital image capturing system was utilized to capture DSI® digital data representative of digital images of each cast of a deformed head and each corresponding model of the corrected head shape and store the DSI® digital data for each digital image in first and second databases, respectively. The first and second databases were utilized to train a neural network. 
     In its continuing efforts, Cranial Technologies further developed a system that utilized these first and second databases to automatically produce digital data representative of a modified head shape from DSI® digital data representative of a deformed head. 
     The data representative of the deformed head is utilized to provide a full size replica of the modified head shape. On that full size replica, a polymer plastic material is formed as a step in the production of a custom DOC BAND® cranial remodeling device. 
     After the polymer plastic material is formed on the full size replica, the polymer plastic material must be cut as step in forming a final DOC BAND® cranial remodeling device. The cutting of the material is along trim lines that are customized for the specific customized DOC BAND® cranial remodeling device. 
     Cranial Technologies further developed a methodology and a computer program implementing that methodology to generate corresponding trim lines for each customized DOC BAND® cranial remodeling device. That methodology is the subject of prior patents owned by Cranial Technologies, Inc. 
     With the methodology and computer program it is possible for to use a Computer Numerical Control (CNC) machine cutting tool to directly cut the shape of the cranial remodeling device in the polymer plastic material utilizing the computer generated trim line. 
     Although it is possible to automatically cut along the computer system generated trim lines, we have determined that it is desirable to first draw or mark the trim lines on the polymer plastic surface. Drawing the trim lines allows a product finisher to use skilled judgment to adjust the trim lines as necessary in finishing the product. 
     We discovered that there is considerable difficulty in drawing or marking the trim lines on the complex three-dimensional surface of a cranial remodeling device. Although CNC machines are particularly useful when cutting a complex three-dimensional bodies, it is difficult to program a tool to just contact the surface of a complex three-dimensional surface with perfect accuracy to provide trim line markings on the surface. The problem is especially aggravated where the surface being marked is a plastic surface. When the plastic surface is digitized, the inherent noise that occurs in the digitization appears as surface variations to the CNC machine 
     We tried to find a marking tool usable in a CNC machine that could be used to draw trim lines as part of our manufacturing process. We found commercially available rigid drawing or marking tools that are suitable for use in CNC machines. However, all of those marking tools require 100% accuracy in locating the surface. If the location of the surface is not perfectly located, the marking tool may impact the surface and break or damage the surface, or the marking tool may not actually touch the surface with the result that the trim line is not drawn, or the marking tool may when drawing the trim line damage the surface in portions, mark the surface in portions, and miss the surface in other portions. 
     Many commercially available marking tools were investigated for suitability in marking trim lines onto polymer plastic three-dimensional complex surfaces. None of the commercially available marking tools was effective. For these and other reasons, we determined that it was desirable to provide apparatus that would consistently and effectively drawing lines onto the complex surface of a three-dimensional object without risk of damage to the surface and without requiring perfect placement onto the surface. 
     SUMMARY 
     In one embodiment of the invention, a tool for depositing material onto a three-dimensional surface is provided. The tool comprises a first tubular member comprising a first guide surface and a second guide surface. The tool further comprises a second tubular member comprising a first guide surface engaging the first tubular member first surface and comprising a second guide surface engaging the first tubular member second surface. A first resilient member is disposed to urge the second tubular member in a first axial direction relative to the first tubular member. A material holder is disposed axially within the second tubular member. A second resilient member is disposed in the tool to urge the holder in a second axial direction opposite to said first axial direction. 
     In another embodiment, a tool for marking a three-dimensional surface is provided. The tool comprises a first tubular member adapted to be carried by a motive spindle of a machine of a type capable of moving said spindle along a plurality of axes. A second tubular member is in telescoping engagement with the first tubular member. A first resilient member urges the second tubular member in a first axial direction relative to the first tubular member. A tubular material holder is disposed axially within the second tubular member. A second resilient member urges the holder in a second axial direction opposite to the first axial direction such that the tubular material holder is retained within the tool. 
     In a further embodiment, apparatus for working a three-dimensional surface is provided. The tool comprises a first tubular member adapted to be carried by a motive spindle of a machine of a type capable of moving said spindle along a plurality of axes. A second tubular member is in telescoping engagement with the first tubular member. A first resilient member urges the second tubular member in a first axial direction relative to the first tubular member. A tool holder is disposed axially within the second tubular member. A second resilient member urges the holder in a second axial direction opposite to the first axial direction such that the tool is retained within the holder. 
     In another embodiment of the invention, a tool for depositing material onto a three-dimensional surface to mark trim lines for a cranial remodeling device is provided. The tool comprises a first tubular member adapted to be received in a spindle of a 5-axis computerized numeric control mill machine. The first tubular member comprises a first guide surface and a second guide surface. The tool further comprises a second tubular member comprising a first guide surface engaging the first tubular member first surface and comprising a second guide surface engaging the first tubular member second surface. A first resilient member is disposed to urge the second tubular member in a first axial direction relative to the first tubular member. A tubular material holder is disposed axially within the second tubular member. The tubular material holder is adapted to retain marking material therein and extending therefrom. A second resilient member is disposed in the tool to urge the holder in a second axial direction opposite to said first axial direction. 
     In yet a further embodiment, a tool for marking a three-dimensional surface is provided to mark trim lines onto the surface prior to cutting the surface to form a cranial remodeling device is provided. The tool comprises a first tubular member adapted to be carried by a motive spindle of a machine of a type capable of moving said spindle along a plurality of axes. A second tubular member is in telescoping engagement with the first tubular member. A first resilient member urges the second tubular member in a first axial direction relative to the first tubular member. A tubular material holder is disposed axially within the second tubular member. The tubular material holder is adapted to hold material for marking the surface A second resilient member urges the holder in a second axial direction opposite to the first axial direction such that the tubular material holder is retained within the tool. 
     In various embodiments of the invention, a graphite marking material is advantageously used in the marking tool to mark trim lines onto a polymer plastic surface 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The invention will be better understood from a reading of the following detailed description in conjunction with the drawing figures in which like reference designators identify like elements, and in which: 
         FIG. 1  illustrates an embodiment of the tool of the invention; 
         FIG. 2  illustrates the tool of  FIG. 1  in a first operational state; 
         FIG. 3  illustrates the tool of  FIG. 1  in a second operational state; and 
         FIG. 4  illustrates the tool of  FIG. 1  in a third operational state; 
         FIG. 5  shows an insert of marking material; and 
         FIG. 6  illustrates the tool of  FIG. 1  mounted in a spindle of a machine. 
     
    
    
     DETAILED DESCRIPTION 
     U.S. Pat. No. 7,127,101 issued Oct. 24, 2006; U.S. Pat. No. 7,142,701 issued Nov. 28, 2006; U.S. Pat. No. 7,162,075 issued Jan. 9, 2007; U.S. Pat. No. 7,177,461 issued Feb. 13, 2007; U.S. Pat. No. 7,227,979 issued Jun. 5, 2007; U.S. Pat. No. 7,242,798 issued Jul. 10, 2007; U.S. Pat. No. 7,245,743 issued Jul. 17, 2007; U.S. Pat. No. 7,280,682 issued Oct. 9, 2007; and U.S. Pat. No. 7,305,369 issued Dec. 4, 2007 are all assigned to Cranial Technologies, Inc., assignee of the present application, and the disclosures contained in each of the patents are expressly incorporated herein by reference. 
     The aforementioned Cranial Technologies Patents describe systems and methodologies to which the present invention is particularly well suited. In particular, U.S. Pat. No. 7,227,979 describes a methodology and system in which trim lines are generated for customized cranial remodeling devices and in which the trim lines are utilized to produce corresponding customized cranial remodeling devices. 
       FIG. 1  illustrates one embodiment of a tool  100  in accordance with the principles of the invention. Tool  100  comprises a first tubular member or outer tube  101 . Outer tube  101  is of cylindrical shape. In other embodiments, outer tube  101  may be of a different shape. One end  101   a  of outer tube  101  is closed by a surface  115   a . Surface  115   a  may be provided by an end cap  115  as shown in  FIGS. 1 - 4 , or by a surface carried by the machine into which tool  100  is used as shown in  FIG. 6 . 
     The other end  101   b  of outer tube  101  has integrally formed thereon a radially inward extending flange or lip  103  that carries a first guide surface  103   a . The inner wall  101   c  of outer tube  101  provides a second guide surface  101   d . 
     A second tubular member or inner tube  105  is disposed partially within and telescopically extending from outer tube  101 . The end  105   a  of inner tube  105  disposed within outer tube  101  has a radially outward extending flange or lip  107 . Lip  107  carries a first guide surface  107   a . First guide surface  107   a  slideably engages second guide surface  101   d  of outer tube  101 . The outer wall  105   b  of inner tube  105  provides a guide surface  105   c . Guide surface  105   c  slideably engages second guide surface  103   a    101   d  of outer tube  101 . 
     A first resilient member or device or spring  111  is disposed within outer tube  101 . One end of spring  111  engages surface  115 . The other end of spring  111  engages the top surface  105   d  of inner tube  105 . Spring  111  is selected such that inner tube  105  extends outside of outer tube  101  a predetermined distance as shown in  FIG. 1 . 
     The other end  105   e  of inner tube  105  carries a tapered outer collar  119  of a chuck or collet assembly  131 . Collar  119  may be affixed to inner tube  105  by any one of a number of conventional means. In the embodiment shown in the drawing figures collar  119  has a threaded portion  119   a  carrying threads that engage mating threads carried by inner tube  105 . 
     A tubular material holder or tubular marking lead or working tool or third tubular member or implement holder or tubular tool holder  123  is telescopically disposed within inner tube  105 . Implement holder  123  includes a collet  121 . Implement holder  123  includes a lip  123   a  that forms a guide surface  123   b . 
     The inner surface  105   f  of inner tube  105  includes a guide surface  105   g . Guide surface  105   g  is slidingly engaged by guide surface  123   b  of implement holder  123 . 
     A second resilient member or spring  127  is disposed within inner tube  105 . One end of spring  127  engages an annular surface  119   b  carried on the inside of collar  119 . The other end of spring  127  engages a surface  123   c  of holder  123 . Spring  127  is selected such that it urges implement holder  123  into inner tube  105 . 
     In the embodiment shown, an insert  500  of a marking material such as that shown in  FIG. 5  is utilized to mark trim lines. It has been determined that use of graphite marking material is particularly advantageous on the polymer plastic material that is utilized in the Doc Band®. 
     To install insert  500  into tool  100 , collar  119  is pushed such that inner tube  105  is fully inserted into outer tube  101 . Spring  127  carries the top of holder  123  into engagement with surface  115 . As first sloped surface of collet  121  disengages second sloped surface of collar  119  it spreads or opens such that insert  500  may be installed into holder  123  as shown in  FIG. 2 . 
     Releasing collar  119  results in spring  127  urging holder  123  away from collar  119 . In this position, collet  121  firmly grips insert  500  and retains it in tool  100 . In addition, spring  111  urges inner tube away from surface  115  such that tool  100  and insert  500  are in the position shown in  FIG. 3   
     With spring  111 , tool  100  may operate in a range of positions from a first position shown in  FIG. 3  to a second position as shown in  FIG. 4 . 
     Turning now to  FIG. 6  tool  100  is inserted into a spindle  600  of a machine that is not shown. Tool  100  is affixed to spindle  600  by setscrews  601 . It will be appreciated by those skilled in the art that other approaches may be used to affix tool  100  to the spindle of a machine. 
     In an embodiment of the invention spindle  600  is that of a commercially available 5-axis computerized numeric control (CNC) machine that can mill a piece stock over three dimensions. The specific machine utilized is a 5-axis commercially available vertical mill that can mill three-dimensional objects with appropriate milling tools. 
     The assignee of the present invention utilizes the machine to mill a full size model of a desired head shape utilizing computer generated data regarding a desired head shape as described in the patents incorporated herein by reference above. After forming the desired head shape, plastic material is formed onto the head shape. The plastic material must be trimmed by cutting along trim lines to form the desired cranial remodeling device. 
     The system described in the referenced patents automatically generates trim lines for each custom cranial remodeling device. Tool  100  permits a milling tool in a CNC machine to be replaced with a marking tool that can draw trim lines rather than cut trim lines. The advantage of drawing the trim lines onto the three-dimensional surface rather than cutting trim lines allows for manual adjustments to be made prior to the cutting. 
     Tool  100  advantageously includes a spring biased mechanism that urges the insert  500  of marking material into engagement with a surface, and when it is in contact with a surface the spring bias permits the insert  500  to rise if the surface “rises” underneath it. 
     Most printers, plotters and other devices are designed to handle surface in two-dimensions only. Tool  100  can “write” or mark on three-dimensional surfaces. This has the additional advantage of compensating for small deviations or errors in how tool  100  is touched off or “zeroed”. Spring loading allows for small errors. 
     Tool  100  accommodates different surfaces, such as flat, round, elliptical, rough, smooth, etc. Regardless of the surface spring loading makes tool  100  adaptable to the surface terrain. 
     Although the embodiment describes a marking lead material, other marking materials may be utilized in tool  100 . Graphite, marking lead, wax, grease, China marker, adhesive, glue, marker, masking material, paint, and fluorescent die are merely representative of the type of material that may be deposited onto a surface utilizing tool  100 . The marking can be either permanent or cleanable or erasable depending on the specific application. In one application, wax could be deposited onto a surface to protect the waxed over portion during an etch operation. 
     By rotating tool  100  at a slow rate while it is in the spindle, the tip of the insert  500  can be kept sharp. 
     Although the embodiment of tool  100  shown an described above requires that the insert  500  be manually advanced, it will be apparent to those skilled in the art that an automatic self-feed utilizing an additional pressure based resilient mechanism may be utilized. 
     Although tool  100  has been described with respect to depositing material onto a surface, it should be further apparent to those skilled in the art that a cutting tool bit may also be used in tool  100  in place of insert  500 . The use of tool  100  with a cutting tool insert has certain advantages. The spring loading of tool  100  can save a work pieces from being damaged in the event of a programming error that would otherwise result in the cutting tool from smashing into the surface of the work piece resulting in destruction or damage to the work piece and/or the tool. 
     In another embodiment of the invention, a sensor could be provided in tool  100  to detect a travel limit of inner tube  105  and/or of holder  123 . The sensor could provide a signal to the machine to stop operation or cause another response to, for example, stop operation of the machine to avoid tool breakage. 
     One particular advantage of tool  100  is that it can simplify programming operation of the machine. By way of example, if it is desired to draw a line across a surface that has rises and dips such as a saw tooth, the line could simply be plotted and the spring loading of tool  100  would follow the surface. Otherwise, it would be necessary to program a more complex line with more accelerations/decelerations—a slower, more inefficient process and tougher on the mill. 
     The invention has been described in terms of various embodiments. It will be apparent to those skilled in the art that various changes and modifications may be made to the embodiments shown and described without departing from the spirit or scope of the invention. It is intended that the embodiments shown and described are illustrative of the principles of the invention and that the invention not be limited to such embodiments. It is intended that the invention be limited in scope only by the claims appended hereto, with the claims being given the broadest scope permissible under the relevant law.