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`US 20040071869Al
`
`(19) United States
`(12) Patent Application Publication
`Gilliam et al.
`
`(10) Pub. No.: US 2004/0071869 A1
`Apr. 15, 2004
`(43) Pub. Date:
`
`(54) METHOD OF COATING A TAPE MEASURE
`BLADE
`
`(76)
`
`Inventors: Edgar T. Gilliam, Franklinton, NC
`(US); James M. Critelli,
`Fuquay-Varina, NC (US)
`
`Correspondence Address:
`COATS & BENNETT, PLLC
`PO BOX5
`RALEIGH, NC 27602 (US)
`
`(21) Appl. No.:
`
`10/268,432
`
`(22) Filed:
`
`Oct. 10, 2002
`
`Publication Classification
`
`(51)
`
`Int. CI? ....................................................... BOSD 1/12
`
`(52) U.S. Cl. ............................................ 427/180; 427/458
`
`(57)
`
`ABSTRACT
`
`A metallic tape blade may be substantially coated with a
`powder and then passed through an induction unit to heat the
`powder and form a coating on the blade, with the blade
`having a concavo-convex cross-section when passing
`through the induction unit. Alternatively, the metallic tape
`blade is substantially covered with a powder consisting
`essentially of nylon having a particle size of 20 microns or
`less and then passed through an induction unit to heat the
`blade and form a nylon coating derived from the powder
`thereon. Alternatively, a nylon coating is applied to the
`metallic tape blade, with the coating having a thickness of
`not more than 0.0015 inches and an abrasion resistance
`according to ASTM D968-81 of at least 30 liters of sand.
`One or more of these aspects may be combined to form a
`tape blade having a protective coating thereon.
`
`50
`
`~
`
`54
`"-.._
`
`66
`
`FUSING
`UNIT
`
`60
`
`64
`
`APEX TOOL GROUP, LLC - EX. 1013-001
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`

`

`US 2004/0071869 Al
`
`24
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`Patent Application Publication Apr. 15,2004 Sbeet 1 of 3
`
`10
`
`~
`
`16
`
`FIG.1
`
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`

`

`Patent Application Publication Apr. 15, 2004 Sheet 2 of 3
`
`US 2004/0071869 Al
`
`12 r
`
`FIG. 2
`
`FIG. 3
`
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`

`Patent Application Publication Apr. 15,2004 Sheet 3 of 3
`
`US 2004/0071869 Al
`
`50
`
`~
`
`54
`\-....
`
`60
`
`(58
`
`66
`
`62
`
`FUSING
`UNIT
`
`POWDER
`STATION
`
`64
`
`FIG. 4
`
`~68
`
`68m
`
`FIG. 5A
`
`FIG. 58
`
`12
`
`12
`
`68m
`
`APEX TOOL GROUP, LLC - EX. 1013-004
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`

`

`US 2004/0071869 A1
`
`Apr. 15, 2004
`
`1
`
`METHOD OF COATING A TAPE MEASURE
`BLADE
`
`FIELD OF THE INVENTION
`
`[0001] The present invention is directed generally to tape
`measures and, more particularly, to a coated tape measure
`blade and a method of making the same.
`
`BACKGROUND OF THE INVENTION
`
`[0002] Modern power return tape measures (or "tape
`rules") typically include a coiled tape that is spring-biased
`towards a retracted position. A housing generally surrounds
`protects the tape and biasing spring and includes an opening
`through which a distal end of the tape extends. The distal end
`of the tape is pulled away from the housing during use, and
`when released, the spring pulls the tape back into the
`housing so that the tape returns to the retracted position.
`
`[0003] The tape blades for such devices are typically
`formed from a metal ribbon that assumes a concavo-convex
`configuration when outside the housing, but that is wound
`into a revolute coil inside the housing with each layer of the
`coil having a fiat cross-section. While the base material of
`the blade is typically metal, the surface of the blade material
`is rarely bare metal. Instead, the blade material is typically
`painted, printed with length indicia, and then coated with a
`polymer coating to improve abrasion resistance and/or
`reduce friction. This polymer coating is typically applied by
`passing the ribbon material over a coating roller and then
`through an oven to cure the coating.
`
`[0004] Obviously, increasing the blade coating thickness
`has the beneficial effect of increasing the abrasion resis(cid:173)
`tance; however, increasing the coating thickness increases
`also the space consumed by the coiled blade, thereby del(cid:173)
`eteriously increasing the overall size of the tape measure.
`
`[OOOS] Separately, the conventional technique of applying
`the polymer coating to the blade material-using a coating
`roller-has proved somewhat problematic, particularly in
`forming a coating of a relatively uniform thickness without
`undesirable voids.
`
`[0006] As such, there remains a need for alternative meth(cid:173)
`ods of coating a tape measure blade. While it is not required,
`it is preferred that the alternative methods address one or
`more of the problems discussed above.
`
`SUMMARY OF THE INVENTION
`
`[0007] The present invention is directed to a coated tape
`measure blade and a novel method of making the same. In
`one embodiment of the invention, a metallic tape blade is
`substantially coated with a powder and then passed through
`an induction unit to heat the powder and form a coating on
`the blade, with the blade having a concavo-convex cross(cid:173)
`section when passing through the induction unit. In another
`embodiment, the metallic tape blade is substantially covered
`with a powder consisting essentially of nylon having a
`particle size of 10-20 microns or less and then passed
`through an induction unit to heat the blade and form a nylon
`coating derived from the powder thereon. In yet another
`embodiment, a nylon coating is applied to the metallic tape
`blade, with the coating having a thickness of not more than
`about 0.001 inches or less per side and an abrasion resistance
`according to ASTM D968-81 of at least 30 liters, and more
`
`preferably at least 40 liters, of sand. In still other embodi(cid:173)
`ments, one or more of these aspects are combined to form a
`tape blade having a protective coating thereon.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0008] FIG. 1 shows a power return tape measure that
`may employ a tape blade constructed in accordance with the
`present invention.
`
`[0009] FIG. 2 is a perspective view of a concavo-convex
`tape blade.
`
`[0010] FIG. 3 is a cross-sectional view of the tape blade
`of FIG. 2.
`
`[0011] FIG. 4 shows a process line for forming a coating
`on the tape blade of FIG. 2.
`
`[0012] FIG. SA shows a top view of a coil having a
`non-circular shape suitable for the induction unit of the
`process line of FIG. 4.
`
`[0013] FIG. SB shows a side view the coil of FIG. SA.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`[0014] As the present invention relates to a coated tape
`measure blade, particularly for so-called power return tape
`measures, a brief discussion of such devices may be helpful
`in understanding the present invention. As illustrated in
`FIG. 1, a power return tape measure, generally designated
`10, typically includes a coilable measuring tape or blade 12
`and an associated housing 20. The distal end of the tape 12
`may include an end hook 14 to prevent it from being
`retracted into the housing 20. A tape-biasing device (not
`shown), such as a spring, is operatively connected to the tape
`12 to bias it towards a retracted orientation. A locking
`mechanism, including a toggle 16 or similar actuator is
`provided to aid in controlling the movement of the tape 12
`into and out of the housing 20. One or both sides of the
`housing 20 may include a clip 18, as desired. The housing
`20 may include a main case or shell 22 and a grip element
`24 mounted on the shell22. Shell22 is preferably made from
`a durable material such as a hardened plastic (e.g., ABS,
`polycarbonate, or the like) and may be constructed from two
`portions joined together by suitable screws 26, as is known
`in the art. The housing 20 is preferably sized to fit within a
`user's hand, and also conveniently stored on a work belt or
`in a toolbox. As the present invention primarily relates to the
`tape blade 12, additional details of the construction of the
`tape measure 10 are not necessary for one of ordinary skill
`in the art to understand the present invention. If additional
`details are desired, see U.S. Pat. Nos. 4,527,334; 4,976,048;
`6,349,482, and U.S. patent application Ser. No. 10/174,629,
`filed Jun. 19, 2002, which are incorporated herein by refer(cid:173)
`ence.
`
`[001S] The tape blade 12 is typically formed from a
`relatively thin metal ribbon 32 shaped to form the desired
`concavo-convex cross-sectional shape (as shown in FIGS.
`2-3) when extended from the housing 20, and the desired fiat
`cross-section when coiled inside the housing 20. The under(cid:173)
`lying metal ribbon 32 is typically a steel alloy, such as
`medium to high carbon steel (e.g., 1095 steel or 1050 steel),
`with a thickness in the general range of 0.004 to 0.0055
`inches. While not required, the ribbon 32 forming the core
`
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`

`US 2004/0071869 A1
`
`Apr. 15, 2004
`
`2
`
`of the tape blade 12 preferably has a uniform thickness
`across its width and along its length. The ribbon material
`itself may be formed into the desired shape using any one of
`a variety of known techniques, such as roll forming. The
`metal ribbon 32 is typically painted and then printed with
`appropriate length indicating indicia 36 using known tech(cid:173)
`niques. Thereafter, the printed tape blade 12 is coated with
`a suitable protective coating 34. The purpose of the coating
`34 is to increase abrasion resistance and/or to provide a low
`friction surface to aid in coiling the blade 12.
`
`[0016] The present invention relates to one or more meth(cid:173)
`ods of coating the tape blade 12, and preferably the painted
`and printed tape blade 12. As such, the discussion will
`assume that the tape blade 12 is painted and printed with the
`length indicating indicia 36 prior to the coating process, but
`this is not strictly required for all embodiments.
`
`[0017] The coating process may take place at a coating
`process line 50, such as that shown in FIGS. 4-5. The coating
`process line 50 typically includes a let-off station 52, a
`coating station 60, and a take-up station 56. The let-off
`station 52 operates in a 10 conventional fashion to supply the
`painted and printed tape blade material 12 to the coating
`station 60, and the take-up station 56 operates in a conven(cid:173)
`tional fashion to receive the coated tape blade 12 from the
`coating station 60. Further, it may be advantageous to
`include suitable accumulators 54,58 on the input and/or
`output portions of the process line 50 so that the tape blades
`12 may be supplied to the coating station 60, and output
`therefrom, in the form of rolls of concatenated blades (e.g.,
`multiple blades 12 riveted end to end), as is known in the art.
`
`[0018] For the preferred embodiments of the invention,
`one primary difference with the prior art coating processes
`lies in the use of a novel process within the coating station
`60. As shown in FIG. 4, the coating station 60 has two
`principle components-the powder unit 62 and the fusing
`unit 66. The powder unit 62 applies a polymer based powder
`64 to the ribbon 32; this powder 64 is subsequently fused
`into a coating 34 in the fusing unit 66. In the powder unit 62,
`the ribbon 32 is routed through a vortex of polymer particles
`64 that have been triboelectically charged. The particles
`themselves are preferably nylon, more particularly nylon 11
`with a particle size of 10-20 microns or less, and preferably
`15 microns or less. Such nylon should be commercially
`available from Atofina Chemicals of Philadelphia, Pa. The
`triboelectric charge is applied by agitating the powder 64
`using one or more blowers (not shown), such as the tri(cid:173)
`boelectric powder spray gun of the type generally described
`in U.S. Pat. No. 5,402,940, which is incorporated herein by
`reference. The mixing action of the powder 64 causes a
`positive static electricity charge (sometimes referred to as a
`triboelectric charge) to build up. The tape blade 12 is
`grounded, such as by grounding a feed roller immediately
`upstream of the powder unit 62, giving the tape blade 12 a
`relatively negative charge (with respect to the powder 64) so
`that the powder particles 64 are attracted to the blade 12. The
`combination of the very small particle size of the powder 64
`and the triboelectric charging is believed to help form a
`uniform layer of powder 64 on the ribbon 32. In addition,
`because a vortex of powder 64 is used, rather than a roller,
`the ribbon 32 may optionally have its "normal" concavo(cid:173)
`convex cross-sectional shape while passing through the
`powder unit 62.
`
`[0019] A powder unit 62 for use with the present invention
`may be formed using a number of off-the shelf components
`supplied by Nordson Corp. of Amherst Ohio. For instance,
`a triboelectric powder spray gun of part numbers 631201,
`631271, 630008, and 133403 may be used in conjunction
`with a model 163567 hopper having a model 631401!
`163555 "tribo pump" and a model 631152 control unit. The
`powder 64 in the hopper is preferably in the form of a
`fluidized bed of powder that is pumped to the triboelectric
`powder spray gun by the tribo pump. The output of the
`triboelectric powder spray gun is fed to a generally cylin(cid:173)
`drical vortex tower tangent to the outer wall thereof. In the
`vortex tower, half the input of charged powder 64 is directed
`along the inside of the outer wall, and half the input is
`deflected by an internal deflector towards a point appro xi(cid:173)
`mately 180° away from the input point. The vortex tower
`may be made from PVC, be approximately eight inches in
`diameter and approximately eighteen inches tall. The bottom
`of the vortex tower may be tilted towards an exhaust port
`leading to filter for pulling powder laden air out of the vortex
`tower for recycling to the hopper. The hopper may also be
`vented via a hose that lead to the vortex tower, with an input
`port approximately 6 inches below the input from the
`triboelectric powder spray gun and offset by approximately
`90°. The bottom of the vortex tower should have a slit cut
`therein to allow for the passage of the blades 12 being
`processed. This slit may optionally be faced with soft
`bristles to help prevent unwanted escape of powder 64 from
`the vortex tower.
`[0020] From the powder unit 62, the powdered ribbon 32
`proceeds, preferably directly, to and through the fusing unit
`66. While traditional coating furnaces are either electrical
`resistance heaters (or more rarely gas-fired ovens), the
`fusing unit 66 for the present invention is preferably based
`on the induction principle wherein a time-varying electro(cid:173)
`magnetic field is applied to the blade 12 via coil 68. In
`preferred embodiments, the electromagnetic field has a
`frequency of approximately 450kHz. Such an electromag(cid:173)
`netic field causes the metallic ribbon 32 to heat up very
`quickly and substantially uniformly. Additionally, the use of
`induction heating allows the blade 12 to have its "normal"
`concavo-convex cross-sectional
`shape while passing
`through the fusing unit 66 at a high line speed (e.g., forty to
`sixty feet per minute) without adverse coating effects pro xi(cid:173)
`mate the lateral edges of the blade 12. The heat from blade
`12 causes the powder 64 to fuse, forming the preferably
`transparent coating 34 on the painted and printed blade 12.
`The blade 12 then passes outside the fusing unit 66 for
`cooling. Note that it is preferred that the blade 12 not
`encounter any rollers or other guides, either while passing
`through the fusing unit 66, or immediately thereafter, until
`the coating 34 has cooled sufficiently; however, if desired,
`the first roller downstream from the fusing unit 66, typically
`disposed ten feet or more downstream, may be so-called
`cooling roller to additionally cool the blade 12. The final
`coating thickness should be on the order of 0.001 inches or
`less on a given side of the blade 12.
`[0021] As described above, the preferred fusing unit 66
`utilizes the induction heating principle. The relevant elec(cid:173)
`tromagnetic field is generated by passing electricity through
`a coil 68, with the blade 12 passing through the central
`opening in the coil 68. Preferably, the coil 68 has a non(cid:173)
`circular shape, such as that shown in FIGS. 5A-5B. As
`shown in FIGS. 5A-5B, the coil 68 may include a main coil
`
`APEX TOOL GROUP, LLC - EX. 1013-006
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`US 2004/0071869 A1
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`Apr. 15, 2004
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`3
`
`section 68m with spaced windings supported by stabilizer
`68s and leads that are insulated from one another by insu(cid:173)
`lator 68i and held together by ties 68t. The coil 68 may be
`formed from Y4 inch cooper tubing, coated with suitable
`ceramic coatings. The coil may have a generally oval center
`opening with an inner dimension of approximately 3¥2
`inches by% inches, as shown in FIGS. 5A-5B. Indeed, if the
`coil 68 is in the shape shown in FIGS. 5A-5B, two or more
`blades 12 can be passed through the coil 68 simultaneously
`without adversely affecting the fusing operation. Of course,
`additionallet-offs 52 and take-ups 56, etc. may be required
`if more than one tape blade 12 is to be coated simultaneously
`using the same coating station 60. Further, the required
`power for the induction coil 68 will vary based on process
`conditions, but a coil 68 of 5 KW running at about 60% is
`believed sufficient for operations with two blades 12 passing
`through the induction unit 66 simultaneously at a line speed
`of 40-60 feet/minute.
`
`It should be noted that the fusing unit 66 using the
`[0022]
`induction principle is capable of generating significant heat
`in the blade 12, and may even entirely melt the blade 12 if
`the blade 12 stops while in the fusing unit 66. Accordingly,
`it may be advantageous to incorporate suitable automatic
`systems that shutoff the coil 68 when line speed drops below
`a given level, such as line speed monitors and switches, etc.
`known in the art. In addition, other suitable safety measures
`known in the art may be employed, such as out-gas exhaust(cid:173)
`ing of the induction unit 66, flame detectors aimed at the coil
`68, and the like.
`
`[0023] One of the purposes of applying a coating 34 to the
`tape blade 12 is to increase the life of the blade 12. As known
`in the art, one useful predictor in estimating blade 12 life is
`the measured abrasion resistance when tested according to
`ASTM D968-81. The results of such testing are usually
`expressed as an amount of falling sand (e.g., X liters of sand)
`until failure is detected. Most, if not all, commercially
`available power return tape blades have a reading of less
`than twenty liters of sand using this test method. In contrast,
`tape blades 12 processed according to the process outlined
`above have a measured abrasion resistance of at least thirty
`liters of sand, with values of forty liters, fifty liters, or
`seventy-five liters of sand or more being more typical.
`Indeed some test results have exceed one hundred liters of
`sand. Thus, processing the tape blades 12 according to such
`a process is believed to lead to substantially improved blade
`life, even with relatively thin (e.g., approximately 0.001 inch
`thick) coatings 34.
`
`[0024] The present invention may, of course, be carried
`out in other specific ways than those herein set forth without
`departing from the essential characteristics of the invention.
`Just by way of non-limiting example, the length indicating
`indicia 36 on the tape blade 12 may be embossed, rather than
`printed, without deviating from the scope of the present
`invention. The present embodiments are, therefore, to be
`considered in all respects as illustrative and not restrictive,
`and all changes coming within the meaning and equivalency
`range of the appended claims are intended to be embraced
`therein.
`
`What is claimed is:
`1. A method of coating a tape measure blade, comprising:
`
`providing a metallic ribbon with length indicating indicia
`thereon;
`
`thereafter, substantially covering at least a segment of said
`ribbon with a powder;
`
`thereafter, passing said segment with said powder thereon
`through an induction unit to heat said segment and
`thereby form a coating from said powder on said
`segment, said segment having a concavo-convex cross(cid:173)
`section when passing through said induction unit.
`2. The method of claim 1 wherein said powder is a
`polymer.
`3. The method of claim 2 wherein said powder comprises
`nylon.
`4. The method of claim 3 wherein said powder consists
`essentially of nylon having a particle size of 20 microns or
`less.
`5. The method of claim 1 wherein said coating is sub(cid:173)
`stantially transparent.
`6. The method of claim 1 further comprising triboelectri(cid:173)
`cally charging said powder and wherein said substantially
`covering said segment with said powder comprises exposing
`said segment to said powder when said powder is triboelec(cid:173)
`trically charged.
`7. The method of claim 1 wherein passing said segment
`with said powder thereon through said induction unit to heat
`said segment comprises passing said segment with said
`powder thereon through an induction unit having a non(cid:173)
`circular coil.
`8. The method of claim 1 wherein said coating has an
`abrasion resistance according to ASTM D968-81 of at least
`30 liters of sand.
`9. The method of claim 1:
`
`wherein said powder consists essentially of nylon having
`a particle size of 25 microns or less;
`
`wherein passing said segment with said powder thereon
`through an induction unit comprises passing said seg(cid:173)
`ment with said powder thereon through an induction
`unit having a non-circular coil; and
`
`wherein said coating is substantially transparent.
`10. The method of claim 9 further comprising triboelec(cid:173)
`trically charging said powder and wherein said substantially
`covering said segment with said powder comprises exposing
`said segment to said powder when said powder is triboelec(cid:173)
`trically charged.
`11. A method of coating a tape measure blade, compris(cid:173)
`ing:
`
`providing a metallic ribbon with length indicating indicia
`thereon;
`
`thereafter, substantially covering at least a segment of said
`ribbon with a powder, said powder consisting essen(cid:173)
`tially of nylon having a particle size of 20 microns or
`less; and
`
`thereafter, passing said segment with said powder thereon
`through an induction unit to heat said segment to form
`a nylon coating from said powder thereon.
`12. The method of claim 11 wherein said passing said
`segment with said powder thereon through an induction unit
`comprises passing said segment with said powder thereon
`through an induction unit having a non-circular coil.
`13. The method of claim 11 wherein said coating is
`substantially transparent.
`14. The method of claim 11 further comprising triboelec(cid:173)
`trically charging said powder and wherein said substantially
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`US 2004/0071869 A1
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`Apr. 15, 2004
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`4
`
`covering said segment with said powder comprises exposing
`said segment to said powder when said powder is triboelec(cid:173)
`trically charged.
`15. The method of claim 11 wherein said passing said
`segment with said powder thereon through an induction unit
`comprises passing said segment with said powder thereon
`through an induction unit with said segment having a
`concavo-convex cross-section when passing through said
`induction unit.
`16. The method of claim 11 wherein said coating has an
`abrasion resistance according to AS1M D968-81 of at least
`30 liters of sand.
`17. The method of claim 16 wherein said coating has an
`abrasion resistance according to AS1M D968-81 of at least
`40 liters of sand.
`18. The method of claim 11:
`
`wherein said segment has a concavo-convex cross-section
`when passing through said induction unit;
`
`wherein passing said segment with said powder thereon
`through an induction unit comprises passing said seg(cid:173)
`ment with said powder thereon through an induction
`unit having a non-circular coil; and
`
`wherein said coating is substantially transparent.
`19. The method of claim 18 further comprising triboelec(cid:173)
`trically charging said powder and wherein said substantially
`covering said segment with said powder comprises exposing
`said segment to said powder when said powder is triboelec(cid:173)
`trically charged.
`20. The method of claim 11 wherein said powder consists
`essentially of nylon having a particle size of 15 microns or
`less.
`21. A method of coating a tape measure blade, compris(cid:173)
`ing:
`
`providing a metallic tape measure blade with length
`indicating indicia thereon;
`
`applying a nylon coating to at least a segment of said
`ribbon, said coating having a thickness of not more than
`0.0015 inches and an abrasion resistance according to
`ASTM D968-81 of at least 30 liters of sand.
`22. The method of claim 21 wherein said abrasion resis(cid:173)
`tance is at least 40 liters of sand.
`
`23. The method of claim 22 wherein said abrasion resis(cid:173)
`tance is at least 50 liters of sand.
`24. The method of claim 23 wherein said abrasion resis(cid:173)
`tance is at least 75 liters of sand.
`25. The method of claim 21 wherein said thickness is
`approximately 0.001 inches or less and said abrasion resis(cid:173)
`tance is at least 40 liters of sand.
`26. The method of claim 21 wherein said coating is
`substantially transparent.
`27. The method of claim 21 wherein applying said coating
`comprises:
`
`substantially covering said segment with a nylon powder;
`
`thereafter, passing said segment with said powder thereon
`through an induction unit.
`28. The method of claim 27 wherein said passing said
`segment with said powder thereon through an induction unit
`comprises passing said segment with said powder thereon
`through an induction unit with a concavo-convex cross(cid:173)
`section.
`29. The method of claim 27 further comprising triboelec(cid:173)
`trically charging said powder and wherein said substantially
`covering said segment with said powder comprises exposing
`said segment to said powder when said powder is triboelec(cid:173)
`trically charged.
`30. The method of claim 21:
`
`wherein said segment has a concavo-convex cross-section
`when passing through said induction unit;
`
`wherein applying said coating comprises substantially
`covering said segment with a nylon powder and there(cid:173)
`after passing said segment with said powder thereon
`through an induction unit having a non-circular coil;
`
`wherein said coating is substantially transparent; and
`
`wherein said abrasion resistance is at least 50 liters of
`sand.
`31. The method of claim 29 wherein said powder consists
`essentially of nylon having a particle size of 20 microns or
`less.
`
`APEX TOOL GROUP, LLC - EX. 1013-008
`
`