Patent Publication Number: US-2004050489-A1

Title: Device and method for peeling film

Description:
TECHNICAL FILED  
       [0001] The invention relates to a method and an apparatus for stripping, in a simple manner, a film adhered on a surface of an article such as a surface of panel of a cathode ray tube, wherein stripping means with a heated edge strips the film adhered on a surface of panel of the cathode ray tube, clamp means clamps stripped end of the film, and then moving means moves the clamp means.  
       BACKGROUND ART  
       [0002] The cathode ray tube (hereinafter referred to as CRT) made of glass has a panel covered with a functional film (hereinafter simply referred to as film) having an antireflection coating to prevent the reflection of surrounding scenery in the panel and an antistatic coating to prevent the panel from being dirty.  
       [0003] This film is made of, for example, polyethylene terephthaiate (PET) which is adhered to the panel with an adhesive made of acrylic resin. To reuse a condemned CRT, it is melt after the film is striped off the surface of panel to be recycled as glass resources. Stripping of the film from the surface of panel prevents the film and the adhesive from being molten in glass cullet that is the molten glass pellet, thereby avoiding reduction of the purity of the recycling glass.  
       [0004] Stripping of the film from the surface of panel can be achieved by, for example, stripping it with a tool such as a knife, softening the adhesive using chemicals to reduce its adhesion, or softening the adhesive by heating the surface of film with a hot-air blower or the like to reduce the adhesion of the adhesive.  
       [0005] However, stripping the film using a tool such as the knife described above and a slotted screwdriver leads to not only work inefficiency and treacherous, but also very laborious because such tool is slippery on the work.  
       [0006] Softening the adhesive using chemicals to reduce its adhesion has an adverse effect on a human body and the environment. Besides, this procedure has a drawback in that it takes much long to strip the film and requires additional processing of the chemicals used.  
       [0007] Heating the surface of film by a hot-air blower or the like causes the adhesive too soft to make it difficult to strip the film off the surface of panel and causes the molten adhesive to remain on the CRT panel, thereby requiring additional process to remove the residual adhesive. Heating the surface using a gas burner in place of the hot-air blower also makes the film itself molten together with the adhesive, thereby failing to strip them.  
       [0008] Cutting into the boundary between edge of the film and the surface of panel of the CRT film using a sufficient physical shock of an air doctor to blow air at high pressure to it completely fails to strip the film off the surface of panel. Using an ultrasonic oscillatory knife has a problem in that vibratory percussion of a cutting edge of the knife against the glass surface of the CRT sometimes breaks the film. Forced detachment of the film with a rotary brush or the like results in an easily stainable sticky mixture of the film and the adhesive, which is rather dirty, so that the film cannot be perfectly striped.  
       DISCLOSURE OF INVETION  
       [0009] It is, therefore, an object of the invention to provide a method and an apparatus, simple in structure, for quickly and securely stripping a film adhered on a surface of an article.  
       [0010] In accordance with one aspect of the invention, there is provided an apparatus for stripping a film adhered to an outer surface of an article, the apparatus comprising a stage for mounting the article thereon with film-adhered surface of the article oriented upward, stripping means having an edge for stripping one end of the film adhered to the outer surface of the article, the stripping means allowing the edge to be heated, clamp means for clamping the one end of film, the one end being stripped by the stripping means, and moving means for moving the clamp means.  
       [0011] In accordance with another aspect of the invention, there is provided a method of stripping a film adhered to an outer surface of an article, the method comprising steps of mounting the article with film-adhered surface of the article oriented upward, stripping side end of the film adhered to the outer surface of the article with a heated edge, and clamping the side end of film stripped at the above stripping step to further strip the film continuously.  
       [0012] According to the method and the apparatus of the invention for stripping the film, it is possible to soften only the adhesive on the back of the film by a heated edge of the stripping means, thereby allowing the edge to smoothly cut into the boundary and stripping the film. By clamping a forward end thus stripped of the film with the cramp means and by moving the clamp means by the moving means, the film may be easily, quickly, and securely stripped off the outer surface of article, to which the film has been adhered. 
     
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
     [0013]FIG. 1 is a schematic perspective view illustrating a configuration of an apparatus for stripping a film off the surface of panel of a CRT according to the invention;  
     [0014]FIG. 2 is a perspective view of a hot knife;  
     [0015]FIG. 3 is a cross sectional view taken along lines A-A of FIG. 2;  
     [0016]FIG. 4 is a cross sectional view taken along lines B-B of FIG. 2;  
     [0017]FIG. 5 is a perspective view of clamp means;  
     [0018]FIG. 6 is a cross sectional view taken along lines C-C of FIG. 5 with a film retaining panel forced against a lower panel;  
     [0019]FIG. 7 is a schematic view of moving means;  
     [0020]FIG. 8 is a plan view in schematic form depicting a relationship between the CRT and the hot knife;  
     [0021]FIG. 9 is a diagram illustrating operations of the apparatus for stripping the film;  
     [0022]FIG. 10A is a fragmentary plan view illustrating Step  1  of a method for stripping a film according to the invention;  
     [0023]FIG. 10B is a fragmentary lateral view illustrating Step  1  thereof;  
     [0024]FIG. 11A is a fragmentary plan view illustrating Step  2  thereof;  
     [0025]FIG. 11B is a fragmentary lateral view illustrating Step  2  thereof; and  
     [0026]FIG. 12 is a diagram illustrating a hot knife according to a second embodiment of the invention. 
    
    
     BEST MODE FOR CARRING OUT THE INVENTION  
     [0027] Referring to the drawings, embodiments of an apparatus for stripping a film according to the invention will now be described below. Although the invention will be particularly described with reference to a film adhered to a surface of panel of the CRT as an example, the invention is generally applied to an article having an outer surface to which a film is adhered.  
     [0028]FIG. 1 is a schematic perspective view illustrating a configuration of the apparatus for stripping the film adhered to the surface of panel of the CRT according to the invention. The apparatus  1  is designed to strip the film  3  adhered to the surface  2   a  of panel of the CRT  2  with an adhesive. The apparatus  1  comprises a stage  5  for mounting the CRT  2  thereon, a stripping mechanism  6  mounted above the stage  5 , and a tool box  7 .  
     [0029] The film  3  is made of, for example, a PET film having a thickness in ranges of 100 to 250 micrometers, and a coat of adhesive  4  having a thickness in the range of 20 to 50 micrometers is adhered to the back of the film (see FIG. 10). An adhesive applied to the film contains 99% of acrylic polymers and 1% of solvent for adhesion.  
     [0030] The stripping mechanism  6  comprises a hot knife  9  for allowing it to be heated and for stripping the film  3 , clamp means  10  for clamping the forward end of the film  3  thus stripped by the hot knife  9 , and moving means  12  for moving the clamp means  10 . The tool box  7  is provided to keep thereon tools such as the hot knife  9 . Details of the clamp means  10  and moving means  12  will be described later.  
     [0031] The invention permits quick and secure stripping of such film  3  adhered to the surface  2   a  of the panel of the CRT  2  with ease by stripping the film  3  off the surface  2   a  of the panel of the CRT  2  with the hot knife  9 , and clamping the forward end of the film thus stripped with the clamp means  10 , and moving the clamp means  10  using the moving means  12 .  
     [0032]FIG. 2 is a perspective view of the hot knife  9 . The hot knife  9  has a substantially rectangular shaped grip section  13  for allowing it to be held, a planer knife section  14  forwardly projecting from the grip section  13 , and a temperature regulation section (not shown) for controlling a temperature of the knife section  14 . The knife section  14  and the temperature regulation section are connected to an end of a code  16 , the other end of which is connected with a control panel (not shown). In FIG. 2, the reference number  15  indicates a temperature regulation dial for setting the temperature of the temperature regulation section.  
     [0033] The knife section  14  is illustratively formed into plane, and served as a heater for heating the film  3  and the adhesive  4  on the back of the film  3  to strip them. The knife section  14  has at the leading end thereof an edge  14   a . The edge  14   a  has a sharp edge portion  14   a - 1  at a front part thereof and a dull edge portion (referred to as break edge portion)  14   a - 2  at a rear part thereof.  
     [0034]FIG. 3 shows a cross section of the sharp edge portion  14   a - 1  taken along lines AA of FIG. 2. The sharp edge portion  14   a - 1  has a function to cut into a boundary between the film and the surface of panel of the CRT and it has an acute angled tip so that it can easily cut into the boundary between the film and the surface of panel of the CRT.  
     [0035]FIG. 4 shows a cross section of the break edge portion  14   a - 2  taken along lines BB of FIG. 2. The break edge portion  14   a - 2  has a flat tip to prevent the film stripped by the sharp edge portion  14   a - 1  from being broken in error.  
     [0036] The combinatory arrangement of the sharp edge portion  14   a - 1  and the break edge portion  14   a - 2  of the edge  14   a  of the hot knife  9  is not limited to the one as shown in FIG. 2. Instead, the break edge portion can be positioned at the front part of the edge and the sharp edge portion in rear part of the edge.  
     [0037] The edge  14   a  of the hot knife  9  may have other various cross-sections such as a ridge-shape cross section, a half ridge cross section, and a slab cross section. In the example shown herein, the knife section  14  is heated by Joule heat. But it may be heated by other means such as, for example, high-frequency induction heating.  
     [0038]FIG. 5 shows a clamp means  10 . FIG. 6 shows a cross section of the clamp means taken along lines C-C of FIG. 5, with a retaining panel  21  pressed against a lower panel  19 . As shown in FIG. 5, the clamp means  10  comprises the lower panel  19 , the retaining panel  21  supported rotatably with a pair of brackets  19   a  formed upwardly on the opposite ends of the lower panel  19  and a shaft  20 , and springs  22  wound around the shaft  20 . A linear transverse protrusion  19   b  for facilitating seizing the stripped end of the film  3  extends across the lower panel  19  at the forward side thereof relative to the brackets  19   a  of the lower panel  19 .  
     [0039] The brackets  19   a ,  19   a  have through-holes both for rotatably supporting opposite ends of the shaft  20  that extends through near one side of the retaining panel  21 . Formed in about the middle of the retaining panel  21  is a transverse groove  21   a  that extends across the retaining panel  21  for engagement with the linear protrusion  19   b . The retaining panel  21  also has three hollows  21   b  at the side where the shaft  20  is extended through with them being spaced apart at prescribed intervals and the respective springs  22  are wound around the shaft  20  in the hollows  21   b . One end of each spring  22  abuts on the lower panel  19 , while the other end thereof abuts on the retaining panel  21 . As a result, the retaining panel  21  is urged to rotate about the shaft  20  by the springs  22  towards the lower panel  19 . When engaging the linear protrusion  19   b  with the groove  21  a, they firmly clamp the striped end of the film  3 , as shown in FIG. 6.  
     [0040]FIG. 7 shows an arrangement of the moving means  12 . A pair of LM guides  26  is provided side by side on the upper front end of the stage  5 , each guide extending in the longitudinal direction of the stage. In addition, a rack gear  27  is provided between the paired LM guides  26 ,  26  with it running parallel with them. The LM guides  26 ,  26  and the rack gear  27  together constitute a guide member  25 . There is provided another guide member  25  on the upper rear end of the stage  5 .  
     [0041] A slider  29  is mounted on a pair of the guide members  25 ,  25  with it extending over the pair of guide members so that the slider  29  can move along the length of the guide members. The lower panel  19 , namely, the clamp means  10  adjoins the slider  29  with them being formed integral with each other. Formed on the underside of the slider  29  are engaging grooves  29   a ,  29   a  for engaging the respective guide members  25 ,  25 . The slider  29  is further provided with a transverse shaft  30  that penetrates the slider  29 . A handle  31  is fixed on the front side end of the shaft  30 . A lever  31  a for rotating the handle  31  forwardly projects from an appropriate position of an outer ring member of the handle  31 . Recesses  29   a - 1 ,  29   a - 1  are further formed in the respective portions in the grooves  29   a ,  29   a  of the slider  29 , the portion including an intersection of the groove with the shaft  30 , and pinion gears  32 ,  32  for engaging respective rack gears  27 ,  27  are fixed on the recesses  29   a - 1 ,  29   a - 1  of the shaft  30 .  
     [0042] As a result, when the engaging grooves  29   a ,  29   a  of the slider  29  engage the respective guide members  25 ,  25 , the rack gears  27 ,  27  engage the respective pinion gears  32 ,  32 . Rotation of the handle  31  by means of a handling of the lever  31   a  causes the shaft  30  and hence the pinion gears  32 ,  32  to be rotated. Since the pinion gears  32 ,  32  engage the respective rack gears  27 ,  27 , the rotation of the pinion gears  32 ,  32  cause the slider  29  and the clamp means  10  to move longitudinally.  
     [0043] In the embodiment, the slider  29  has manually been movable using the handle  31 . The slider  29 , however, may be driven using an actuator such as a motor and a cylinder instead of the handle  31 .  
     [0044]FIG. 8 is a plan view in schematic form depicting a relationship between the CRT  2  and the knife section  14  of the hot knife  9 . The film  3  has been adhered to the surface  2   a  of panel of the CRT  2  using an adhesive by means of a rubber pressure roller of a dedicated adhesive applicator.  
     [0045]FIG. 9 is a diagram illustrating operations of the apparatus  1  for stripping the film. The CRT  2  is held in a upright position within the stage  5  with the surface  2   a  of panel thereof being oriented upward, the right and left ends thereof being held with rubber members  34 ,  34  fixed on the free ends of respective cylinder rods of air cylinders  33 ,  33  and the funnel-shaped end thereof being supported with a mount  37  or the like.  
     [0046] In operation, the edge  14   a  of the knife section  14  of the hot knife  9  is heated and abutted onto the upper right end of the film  3  (Step  1 ). The end of the film  3  lined with the adhesive  4  (hereinafter referred to simply as film  3 ) is stripped with the heated edge  14   a  of the knife section  14  of the hot knife  9  (Step  2 ).  
     [0047] The clamp means  10  then clamps the stripped end of the film  3  (Step  3 ). With the stripped end of the film  3  clamped by the clamp means  10 , the handle  31  is rotated counterclockwise with the handling of the lever  3  la to allow the slider  29  and the clamp means  10  to move along their moving way to the left, thereby causing the cramped end of the film  3  to be moved to the left to strip the film (Step  4 ).  
     [0048] As the film  3  is completely stripped off the surface  2   a  of panel of the CRT  2  by the leftward motion of the slider  29  and the clamp means  10 , the film  3  automatically rolls up soon by itself according to a trick of roll-up-behavior due to tensile deformation it had during stripping (Step  5 ).  
     [0049] Steps  1  and  2  will be further described more in detail. FIG. 10A is a fragmentary plan view illustrating Step  1  and FIG. 1 OB is a fragmentary lateral view illustrating Step  1 . FIG. 11A is a fragmentary plan view illustrating Step  2  and FIG. 11B is a fragmentary lateral view illustrating Step  2 .  
     [0050] As shown in FIGS. 10A and 10B, the edge  14   a  of the knife section  14  of the hot knife  9  abuts on the upper right end of the film  3  adhered to the panel surface  2   a  of the CRT  2  with the adhesive  4 . As the heated knife section  14  softens the adhesive  4 , this allows the sharp edge portion  14   a - 1  of the edge  14   a  to smoothly cut into the underside of both of the film  3  and the adhesive  4 .  
     [0051] Since the melting point of the adhesive  4  is lower than those of the film  3  and the glass of the CRT  2 , the temperature regulation section sets a temperature of the knife section  14  of the hot knife  9  to a temperature close to the melting point of the adhesive  4 , thereby softening only the adhesive  4 . In this embodiment, the knife section  14  of the hot knife  9  heated to a temperature in the range of 70 to 100° C. is used. Because the softening temperature of the adhesive  4  is very low as compared with the melting points of the film  3  and the glass of the CRT  2 , only the adhesive  4  is sufficiently softened or melt to allow the knife section  14  to cut thereinto.  
     [0052] As shown in FIGS. 11A and 11B, when user of the hot knife  9  moves the knife section  14   a  of the hot knife  9  toward himself or herself, the stripped end of the film  3  and the adhesive  4  stripped by the sharp edge portion  14   a - 1  continuously ride on the break edge portion  14   a - 2  without being broken.  
     [0053] Since the temperature of the knife section  14  of the hot knife  9  is set close to the melting point of the adhesive  4 , only the adhesive  4  is softened or melt, which permits the knife section  14  to cut thereinto without difficulty. Since the edge  14   a  of the knife section  14  is formed of the sharp edge portion  14   a - 1  and the break edge portion  14   a - 2 , the sharp edge portion  14   a - 1  may cut thereinto without difficulty as well as the break edge portion  14   a - 2  can effectively prevent the stripped film  3  to be broken.  
     [0054]FIG. 12 is a diagram showing a hot knife according to a second embodiment of the invention. The hot knife  35  according to the second embodiment has a generally elongate knife-shape and has an edge  35   a  on one side thereof The edge  35   a  is formed of only a sharp edge portion. When the hot knife  35  is used for the CRT  2  having a surface of panel with convex in the direction of the shorter length thereof, a shape of the hot knife  35  can be set so as to fit the curvature of the surface  2   a  of panel along the direction of the shorter length thereof In addition, the shape of the hot knife  35  can be also set so as to freely move upward and downward according to force received from the surface  2   a  of panel.  
     [0055] The user moves the hot knife  35  toward the film  3  with the hot knife  35  being closely contact with a side end of the surface  2   a  of panel of the CRT  2  until the edge  35 a of the hot knife  35  abuts on a side end of the film  3 . The heated knife  35  soften the adhesive  4 , thereby enabling the edge  35   a  to smoothly cut into the underside of both of the film 3  and the adhesive  4 . Subsequent steps are the same as described above. Accordingly, the side end of the film  3  and the adhesive  4  can be stripped very easily and quickly in an automated manner.  
     [0056] Although the apparatus for stripping the film of the invention has been described with reference to the above preferred embodiments in which the film adhered to the surface  2   a  of panel of the CRT  2  is stripped, the invention may be applied to any case where a film adhered to the article other than the CRT is tripped. For example, the invention can be used to strip any film such as film covering plasma display or LCD display and to strip deflection plates.  
     [0057] As described above, according to the invention, the heated edge of the knife softens only the adhesive on the back of the film, thereby allowing a smooth cut of the edge and a strip of the film. Clamping the stripped end of the film by the clamping means and moving the clamping means by the moving means allow the film adhered to an outer surface of an article to be easily, quickly, and securely stripped.  
     [0058] Since the apparatus has simple structure, thereby allowing it to be constructed in a manually operable form as well as an automated form, which is cost-effective.  
     [0059] According to the invention, the film can be entirely stripped off an outer surface of an article, so that any further cleaning process, e.g. wiping of the outer surface of the article, is not needed.  
     [0060] The invention does not require any costly thermal energy needed in generating hot air or heating an object to a high temperature, resulting in low running cost.  
     [0061] The film, after stripped by the clamp means and the moving means, automatically rolls up by itself due to the residual distortion created in the film during the forced stripping, thereby allowing an easy-to-process post-removal step.  
     INDUSTRIAL APPLICABILITY  
     [0062] As described above, the apparatus for stripping the film according to the invention is suited for stripping a film adhered to an outer surface of an article such as a film covering a CRT, a plasma display or an LCD display, and a deflection panel.