Abstract:
A hand held masking machine is described having one or more of the following features: a structurally designed metal frame, a directional handle with thumb grip, a cutting blade with a slotted adjusting means, a sheet reel including a wire spring with four pressure points for various core sizes, and a tape reel with a tapered face and flexible ribs that holds a variety of tape widths.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of masking machines. Particularly, it relates to masking machines such as those used for applying tape and other surface preparatory materials. More particularly, the invention relates to improvements to enhance the utility of a masking machine. 
     BACKGROUND 
     Devices for the application of tape and other surface preparatory materials, such as paper, plastic sheets, etc., are well known and are generally referred to as masking machines. Generally, masking machines are employed for protecting a designating portion of a surface from a finish or treatment applied to an adjacent portion of the surface in preparation for painting, trimming and other finishing techniques; for example, in general painting and decorative trimming of vehicle bodies, walls of buildings and other large and small items. 
     There is a need to create masking machines with improved mechanical properties and enhanced ergonomics for the user. For example, there is a need to provide for a masking machine one or more of the following: an ergonomic thumb grip, a directional handle for improved dispensing control and improved cutting of sheet and tape, a blade slot fastened with screw or thumbscrew to masking machine to allow smooth adjustment and quick changing of sizes of the cutting blade, an improved sheet reel spring that holds a masking roll evenly onto a sheet reel, and a tapered spring that allows the masking roll to slip onto a tape reel. 
     Information relevant to hand held devices can be found in U.S. Pat. No. 3,950,214 (Pool et al.), U.S. Pat. No. 4,096,021 (Pool et al.), U.S. Pat. No. 4,379,019 (Pool), U.S. Pat. No. 4,667,891 (Pool), U.S. Pat. No. 4,783,016 (Pool), U.S. Pat. No. 4,913,767 (Longworth), U.S. Pat. No. 5,667,636 (Cayford et al.); each of the foregoing United States Patent is hereby incorporated herein by reference. Each one of these referenced items, however, suffers from one or more of the needs cited above. 
     For example, one disadvantage is that they do not use an ergonomic thumbgrip. 
     For example, another disadvantage is that they do not have a blade slot fastened with a screw or thumbscrew to the masking machine to allow smooth adjustment and quick changing of sizes of the cutting blade. 
     SUMMARY 
     It is an object of the present invention in one embodiment to provide a hand held masking machine for dispensing sheet and tape to a surface comprising: a frame having an outer side and an inner side, and a forward portion and a rearward portion; an offset section to the frame displaced in the direction of the outer side of the frame; a tape roll holder mounted on the outer side of the rearward portion of the frame for rotation about a first axis, the tape roll holder adapted to have a roll of tape mounted thereon; a reel mounted on the inner side of the offset section of the frame for rotation about a second axis, the reel adapted to have a roll of sheet having a hollow cylindrical bore mounted thereon for rotation about the second axis; a offset bracket mounted on the frame between the forward and reward positions and extending in a direction substantially parallel to the second axis and away from the inner side of the frame; a handle including a thumbgrip secured to the offset bracket and depending from the handle bracket so that the hand of the user of the masking machine is spaced from the inner side of the frame; and a guide bar having a slotted adjusting means mounted on the front portion of the frame. Preferably, the reel further comprises two retention members coupled thereto, each retention member having two outwardly projecting contact portions, and more preferably the reel further comprises at least two fluted outer surfaces. Also preferably, the tape roll holder has an inner end closer to the frame and an outer end and further comprises three radially extending circumferentially spaced hub portions having longitudinally extending ribs that define a peripheral surface that is tapered from the inner end to the outer end and adapted to the bore of the core of the tape roll. In a another preferred embodiment, the guide bar having the slotted adjusting means mounted on the forward portion of the frame comprises a mounting bracket mounted on the forward portion of the frame and extending inwardly from the frame in a direction substantially parallel to the second axis and a nose plate having a locking mechanism coupled to the mounting bracket and wherein the guide bar comprises an adjustable blade slot; wherein the guide bar is coupled to the nose plate using the locking mechanism, and more preferably the locking mechanism is selected from the group consisting of set screw, thumb screw or screw lock. In yet another preferred embodiment, the reel further comprises two retention members coupled thereto, each retention member having two outwardly projecting contact portions, and more preferably the reel further comprises at least two fluted outer surfaces. In another preferred embodiment, the invention further comprising a tensioning means coupled to the inner side of the frame wherein the tensioning means functions to contact the tape to the edge of the sheet, and more preferably, the tensioning means comprises an arm having a tensioning fixed end, a tensioning free end, a secured projection and a torsion spring wherein the torsioning fixed end is movably coupled to the inner portion of the frame such that the secured projection is urged toward the reel. 
     The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its structure and its operation together with the additional object and advantages thereof will best be understood from the following description of the preferred embodiment of the present invention when read in conjunction with the accompanying drawings. Unless specifically noted, it is intended that the words and phrases in the specification and claims be given the ordinary and accustomed meaning to those of ordinary skill in the applicable art or arts. If any other meaning is intended, the specification will specifically state that a special meaning is being applied to a word or phrase. Likewise, the use of the words “function” or “means” in the Description of Preferred Embodiments is not intended to indicate a desire to invoke the special provision of 35 U.S.C. §112, paragraph 6 to define the invention. To the contrary, if the provisions of 35 U.S.C. §112, paragraph 6, are sought to be invoked to define the invention(s), the claims will specifically state the phrases “means for” or “step for” and a function, without also reciting in such phrases any structure, material, or act in support of the function. Even when the claims recite a “means for” or “step for” performing a function, if they also recite any structure, material or acts in support of that means of step, then the intention is not to invoke the provisions of 35 U.S.C. §112, paragraph 6. Moreover, even if the provisions of 35 U.S.C. §112, paragraph 6, are invoked to define the inventions, it is intended that the inventions not be limited only to the specific structure, material or acts that are described in the preferred embodiments, but in addition, include any and all structures, materials or acts that perform the claimed function, along with any and all known or later-developed equivalent structures, materials or acts for performing the claimed function. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of one preferred embodiment of a masking dispenser handle with thumbgrip. 
         FIG. 2  is a horizontal view of one preferred embodiment of an adjustable blade slot and set screw. 
         FIG. 3  is a perspective view of one preferred embodiment of a blade/nose assembly. 
         FIG. 4  is a bottom view of one preferred embodiment of a four point sheet reel spring(s). 
         FIG. 5  is a detailed view of one preferred embodiment of a sheet reel with spring(s). 
         FIG. 6  is a bottom view of one preferred embodiment of a tape reel with tapered face. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Turning now to the drawings in which like reference characters indicate corresponding elements throughout the several views, attention is first directed to  FIG. 1  which shows a hand held masking machine including a frame  20  having substantially a side section  22 , offset section  23  and offset bracket  24 . Offset section  23  and bracket  24  extend in opposite directions from side section  22 . For purposes of orientation, it is considered that frame  20  includes a forward portion  25  and a rearward portion  27  and an inner side  510  and an outer side  520 , as further seen in  FIGS. 1 and 2 . At the forward portion  25 , frame  20  is provided with a mounting bracket  28  which is coupled to a nose plate  26  having outer arcuate surface  29 . Frame  20 , including each of the foregoing named elements, may be made of any material that would provide sufficient structural strength, but is preferably made from material such as plastic and/or metal, and is more preferably made from steel preferably having structural features (such as bends) to increase the structural integrity. Preferably, the mounting bracket  28  is of any material that would provide sufficient structural strength, but is preferably made from material such as plastic and metal, and/or is more preferably made from a plastic. 
     An elongate guide bar  30 , stamped from relatively thin sheet metal, is detachably carried by nose plate  26  that is coupled to the mounting bracket  28 . Guide bar  30  includes an arcuate portion  32  and serrated cutting edge  33 . Orientated perpendicularly to side section  22 , guide bar  30  further includes a fixed end  34  detachably secured to nose plate  26  that is coupled to the mounting bracket  28  and a free end  35 . Arcuate surface  29  of nose plate  26  is matingly received within arcuate portion  32 . 
     Tape roll holder  36  is rotatably mounted upon a spindle, not immediately illustrated, integral with rearward portion  27  of frame  20 . Holder  36  is retained upon the spindle by means of a washer  37  and a screw  38  which is threaded into the spindle. Holder  36  rotates about a first axis substantially parallel to the screw  38  length (longitudinal axis of the screw), which is generally parallel to guide bar  30  and especially cutting edge  33 . A roll of coiled, pressure-sensitive tape having a core with a bore may be detachably carried by tape roll holder  36 . 
     A roll of coiled sheet (also called sheet material or masking material), for example paper or plastic, is held by a reel holder  90  rotatably carried by offset section  23 . The reel  90  is rotatable about a second axis which is parallel to the first axis of the roll holder  36 . 
     A handle  50  including a thumbgrip  51  for optimal control and comfort, having an axis generally parallel to side section  22  and generally perpendicular to axes of the tape roll holder  36  and reel  90 , extends from offset bracket  24 . During operation, a human hand holds handle  50  with the thumb on the thumbgrip  51  and moves the masking machine in a direction to dispense the tape and sheet. Accordingly, as sheet is dispensed and remains stationary, tape roll and sheet roll rotate. While the thumbgrip  51  may be made of any suitable material such as plastic, metal or wood, the presently preferred material is plastic. The sheet roll is offset relative to the tape roll such that tape overlaps one end of the sheet roll. Therefore, tape includes a first continuous component which is secured to the edge of the sheet and a second component which is available for continuous adhesion to the surface to be masked. Arcuate portion  32  of guide bar  30  functions as a shoe wiping along tape to ensure adhesion to the surface. 
     In the preferred embodiment shown in  FIG. 2 , the guide bar  30  (some times called a cutting blade) includes a slotted adjusting means such as a blade slot  210  and a locking mechanism  220  to couple the guide bar  30  to the nose plate  26 . Preferably, the locking mechanism  220  may be a set screw, thumb screw or screw lock that allows the blade to be adjusted in a continuous manner, and more preferably without tools. 
     In the preferred embodiment shown in  FIG. 3 , that further shows a different view of the nose plate  26  that is coupled to the mounting bracket  28 . Preferably, the nose plate  26  accommodates industry standard cutting blades.  FIG. 3  also shows a tensioning means  60  for applying tension to the outer surface of the sheet roll and checking uncoiling of the sheet. It is seen that the improved sheet tensioning means  60  includes an arm  62  having tensioning fixed end  63 , tensioning free end  64 , secured projection  78  and a torsion spring  73  (or other biasing means) such that the fixed end  63  is movingly coupled to the frame  20  and the torsion spring  73  functions to urge the secured projection  78  toward the reel  90  to contact the tape to the edge of the sheet. Such tensioning means are well known and have been described U.S. Pat. No. 4,667,891 which has been incorporated by reference herein. 
     Attention is now directed to the preferred embodiment shown in  FIGS. 4 and 5 , in which is seen a retention member  104  for stabilizing the inner core of the sheet (sometimes called a masking roll) material as it is being dispensed. In accordance with the masking machine described in connection with  FIGS. 1 through 3 , a spindle  750  extends from offset section  23  of frame  20  in a direction toward the free end  35  of guide bar  30 . The reel  90  includes a holder  77 , having inner end  93 , outer end  94  and fluted outer surface  95  preferably comprising core stability ribs  310  (a preferred embodiment of the holder  77 ) and more preferably auxiliary ribs  320 . It further includes a blind bore  97  which is rotatably journaled upon the spindle. Screw  98 , passing through washer  99  and outer end  94 , threadedly engages the free end of spindle  750  for attachment of holder  77  to frame  20 . Conventional prior art practice teaches that the fluted outer surface  95  is slightly larger than the bore of the cardboard core of the sheet roll whereby the flutes partially embed within the core for retention of the sheet roll. 
     Retention member  104  (also known as a spring or contact spring), fabricated of a flexible material such as music wire, includes contact elements  105  and center elements  106 . Each contact element  105  is bent to form two outwardly projecting contact portions  109 . While not being held to this theory, it is believed that the retention member  104  form two outwardly projecting contact portions  109  (also called a double lobed spring) that increases the stability of the sheet (also known as masking material) roll on the reel. 
     The improved tape roll holding means of the instant invention, shown in  FIGS. 1-4  and  6  includes a tape roll holder  36  having inner end  123 , outer end  124  and a plurality of three radially extending circumferentially spaced hub portions  410  tapered on the outer surface  125  and each having each having longitudinally extending ribs  127 . The outer surface  125  of the three radially extending circumferentially spaced hub portions  410  and the longitudinally extending ribs  127  define a peripheral surface that is adapted to the bore of the core of the tape roll. Spaced apart, outwardly projecting longitudinally extending ribs  127 , that are also tapered from larger to smaller from the inner end  123  to the outer end  124 , normally engage the bore of the core of the tape roll. Another bore extends axially through tape roll holder  36 . Screw  38  passing through bore and carrying washer  37  is threaded into spindle  128  for attachment of holder  38  to frame  20  in accordance with conventional practice. Tape roll holder  36  may be made of any material of sufficient strength, such as metal, wood or plastic, but is preferably formed of plastic in accordance with conventional injection moulding techniques. 
     The preferred embodiment of the invention is described above in the Drawings and Description of Preferred Embodiments. While these descriptions directly describe the above embodiments, it is understood that those skilled in the art may conceive modifications and/or variations to the specific embodiments shown and described herein. Any such modifications or variations that fall within the purview of this description are intended to be included therein as well. Unless specifically noted, it is the intention of the inventor that the words and phrases in the specification and claims be given the ordinary and accustomed meanings to those of ordinary skill in the applicable art(s). The foregoing description of a preferred embodiment and best mode of the invention known to the applicant at the time of filing the application has been presented and is intended for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and many modifications and variations are possible in the light of the above teachings. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application and to enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.