Compact composite handrails with enhanced mechanical properties
10287133 ยท 2019-05-14
Assignee
Inventors
Cpc classification
B32B1/00
PERFORMING OPERATIONS; TRANSPORTING
B32B2250/44
PERFORMING OPERATIONS; TRANSPORTING
B32B2307/54
PERFORMING OPERATIONS; TRANSPORTING
B32B27/12
PERFORMING OPERATIONS; TRANSPORTING
B32B3/04
PERFORMING OPERATIONS; TRANSPORTING
B32B2274/00
PERFORMING OPERATIONS; TRANSPORTING
International classification
B32B7/02
PERFORMING OPERATIONS; TRANSPORTING
B32B3/04
PERFORMING OPERATIONS; TRANSPORTING
B32B5/02
PERFORMING OPERATIONS; TRANSPORTING
B32B1/00
PERFORMING OPERATIONS; TRANSPORTING
B32B3/08
PERFORMING OPERATIONS; TRANSPORTING
B32B27/12
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A handrail includes a carcass, a stretch inhibitor arranged within the carcass, a cover bonded to the carcass, and a sliding layer secured to the carcass. At a central width axis of the handrail, a face height between an upper exterior surface of the cover and a bottom surface of the sliding layer may be less than about 8.0 mm. The carcass may be formed of a first thermoplastic material, the cover may be formed of a second thermoplastic material, and the first thermoplastic material may be harder than the second thermoplastic material. The first thermoplastic material may have a modulus at 100% elongation of between 10 and 16 MPa, and may have a hardness of between 93 and 96 Shore A.
Claims
1. A handrail, comprising: a carcass comprising a first side carcass portion, a second side carcass portion spaced apart from the first side carcass portion, and a central carcass portion of generally uniform thickness extending between the first and second side carcass portions, the carcass tapering in thickness around the first and second side carcass portions, the central carcass portion defining an upper interior surface, and the first and second side carcass portions defining first and second concave interior surfaces, respectively, adjoining the upper interior surface on either side thereof; a stretch inhibitor arranged within the central carcass portion; a cover bonded to the carcass, the cover comprising a first side cover portion covering the first side carcass portion, a second side cover portion covering the second side carcass portion, and a central cover portion of generally uniform thickness extending between the first and second side cover portions adjacent to the central carcass portion, the central cover portion defining an upper exterior surface, the first and second side cover portions defining first and second convex exterior surfaces, respectively, adjoining the top exterior surface on either side thereof, the first and second side cover portions further defining generally opposed first and second side interior surfaces, respectively, and the first and second side cover portions yet further defining first and second lower interior surfaces, respectively, adjoined between the first and second concave interior surfaces and the first and second side interior surfaces, respectively; and a sliding layer secured at least to the upper interior surface and the first and second concave interior surfaces, wherein, at a central width axis of the handrail, a face height between the upper exterior surface and a bottom surface of the sliding layer is less than about 8.0 mm, wherein the carcass is formed of a first thermoplastic material, the cover is formed of a second thermoplastic material, and the first thermoplastic material is harder than the second thermoplastic material, and wherein the first thermoplastic material has a modulus at 100% elongation of between 12 and 15 MPa and a hardness of between 93 and 96 Shore A.
2. The handrail of claim 1, wherein the face height is less than about 7.5 mm.
3. The handrail of claim 2, wherein the face height is between 7.0 mm and 7.5 mm.
4. The handrail of claim 3, wherein, at a central height axis of the handrail, side thickness dimensions between each of the first and second convex exterior surfaces and a respective inner surface of the sliding layer is less than about 8.0 mm.
5. The handrail of claim 4, wherein the side thickness dimension is less than about 7.5 mm.
6. The handrail of claim 5, wherein the side thickness dimension is between 7.0 mm and 7.5 mm.
7. The handrail of claim 1, wherein the first thermoplastic material has a hardness of between 94 and 95 Shore A.
8. The handrail of claim 1, wherein a lip stiffness force of at least 10 kg is required to increase a mouth width between the first and second side interior surfaces by 7 mm in an extruded section, measured using first and second jaw elements applying load to the first and second side interior surfaces, respectively, of a test piece of the extruded section, each of the first and second jaw elements extending a length of approximately 30 mm, and the length of the test piece substantially exceeding the length of the first and second jaw elements.
9. The handrail of claim 1, wherein a lip stiffness force of at least 7 kg is required to increase a mouth width between the first and second side interior surfaces by 7 mm in a spliced section, in which a joint is formed between ends of two separate lengths of the handrail, measured using first and second jaw elements applying load to the first and second side interior surfaces, respectively, of a test piece of the spliced section, each of the first and second jaw elements extending a length of approximately 30 mm, and the length of the test piece substantially exceeding the length of the first and second jaw elements.
10. The handrail of claim 1, wherein the first thermoplastic material is polyester thermoplastic polyurethane having a melt flow index of between 5 and 20 g, and the second thermoplastic material is polyester thermoplastic polyurethane having a melt flow index of between 20 and 40 g.
11. The handrail of claim 1, wherein the sliding layer comprises yarns having a residual shrinkage of at least 7.0%.
12. In combination, the handrail of claim 1 wound about a reel to form a spool of the handrail maintained in a reverse bend orientation, in which the first and second side carcass portions and the first and second side cover portions that are spaced from the stretch inhibitor and a neutral axis of the handrail are placed under slight tension.
13. An intermediate handrail product, comprising: a sliding layer comprising a planar portion and first and second upstanding edge portions; a carcass on the sliding layer and centrally disposed between the first and second upstanding edge portions, the carcass being generally rectangular and comprising first and second edges spaced apart from the first and second upstanding edge portions, respectively; a stretch inhibitor arranged within the carcass; and a cover covering the carcass, and extending between the upstanding edge portions, wherein, between each of the upstanding edge portions and the respective edge of the carcass, the cover contacts the sliding layer, wherein the carcass is formed of a first thermoplastic material, and wherein the first thermoplastic material has a modulus at 100% elongation of between 12 and 15 MPa and a hardness of between 94 and 95 Shore A.
14. The intermediate handrail product of claim 13, wherein the cover comprises: first and second bottom surfaces that are in contact with the planar portion; first and second side surfaces that are in contact with the first and second upstanding edge portions, respectively; and an upper surface having first and second raised portions and a valley between the first and second raised portions, and the first and second raised portions are offset inwardly in relation to the respective first and second edges of the carcass.
15. The intermediate handrail product of claim 14, wherein: a central height dimension between the valley and an inner surface of the sliding layer is about 8.2 mm; a raised height dimension between the first and second raised portions and the inner surface of the sliding layer is about 10.5 mm; and a valley width dimension between the first and second raised portions is about 62.0 mm.
16. The intermediate handrail product of claim 15, wherein: a carcass height dimension between a top surface of the carcass and an inner surface of the sliding layer is about 6.0 mm; a carcass width dimension between the first and second edges of the carcass is about 67.0 mm; and a product width dimension between outer surfaces of the upstanding edge portions is about 92.0 mm.
17. The intermediate handrail product of claim 14, wherein each of the upstanding edge portions comprises a curved end that is embedded within the cover.
18. The intermediate handrail product of claim 13, wherein: the cover is formed of a second thermoplastic material, and the first thermoplastic material is harder than the second thermoplastic material; and the first thermoplastic material is polyester thermoplastic polyurethane having a melt flow index of between 5 and 20 g, and the second thermoplastic material is polyester thermoplastic polyurethane having a melt flow index of between 20 and 40 g.
19. The intermediate handrail product of claim 13, wherein the sliding layer comprises yarns having a residual shrinkage of at least 7.0%.
20. A handrail, comprising: a carcass comprising a first side carcass portion, a second side carcass portion spaced apart from the first side carcass portion, and a central carcass portion extending between the first and second side carcass portions, the carcass formed of a first thermoplastic material that has a modulus at 100% elongation of between 12 and 15 MPa and a hardness of between 93 and 96 Shore A; a stretch inhibitor arranged within the central carcass portion; a cover bonded to the carcass, the cover comprising a first side cover portion covering the first side carcass portion, a second side cover portion covering the second side carcass portion, and a central cover portion extending between the first and second side cover portions adjacent to the central carcass portion, the central cover portion defining an upper exterior surface; and a sliding layer secured to the carcass and having a bottom surface, and, at a central width axis of the handrail, a face height between the upper exterior surface and the bottom surface is between 7.0 mm and 7.5 mm.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The drawings included herewith are for illustrating various examples of apparatuses and methods of the present disclosure and are not intended to limit the scope of what is taught in any way. In the drawings:
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DETAILED DESCRIPTION
(12) Various apparatuses or methods will be described below to provide an example of an embodiment of each claimed invention. No embodiment described below limits any claimed invention and any claimed invention may cover apparatuses and methods that differ from those described below. The claimed inventions are not limited to apparatuses and methods having all of the features of any one apparatus or method described below, or to features common to multiple or all of the apparatuses or methods described below. It is possible that an apparatus or method described below is not an embodiment of any claimed invention. Any invention disclosed in an apparatus or method described below that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicant(s), inventor(s) and/or owner(s) do not intend to abandon, disclaim or dedicate to the public any such invention by its disclosure in this document.
(13) Referring to
(14) In the example illustrated, the carcass 12 includes a first side carcass portion 20, a second side carcass portion 22 spaced apart from the first side carcass portion 20, and a central carcass portion 24 of generally uniform thickness extending between the first and second side carcass portions 20, 22. The stretch inhibitor 14 is shown arranged within the central carcass portion 24. The carcass 12 is shown tapering in thickness around the first and second side carcass portions 20, 22. The central carcass portion 24 delineates an upper interior surface 26. The first and second side carcass portions 20, 22 delineate first and second concave interior surfaces 28, 30, respectively. The first and second concave interior surfaces 28, 30 adjoin the upper interior surface 26 on either side thereof.
(15) In the example illustrated, the cover 16 is bonded directly to the carcass 12 at an interface to form a continuous body. The cover 16 includes a first side cover portion 32 covering the first side carcass portion 20, a second side cover portion 34 covering the second side carcass portion 22, and a central cover portion 36 of generally uniform thickness extending between the first and second side cover portions 32, 34, adjacent to the central carcass portion 24. The central cover portion 36 delineates an upper exterior surface 78. The upper exterior surface 78 may exhibit a minor convex curve, as illustrated.
(16) In the example illustrated, the first and second side cover portions 32, 34 delineate first and second convex exterior surfaces 38, 40, respectively. The first and second convex exterior surfaces 38, 40 adjoin the top exterior surface 78 on either side thereof.
(17) In the example illustrated, the first and second side cover portions 32, 34 further delineate generally opposed first and second side interior surfaces 42, 44, respectively. The first and second side cover portions 32, 34 may each have increasing thickness towards the first and second side interior surfaces 42, 44, respectively, which compensates for the tapering of the carcass 12.
(18) In the example illustrated, the first and second side cover portions 32, 34 yet further delineate first and second lower interior surfaces 46, 48. The first lower interior surface 46 is shown adjoined between the first concave interior surface 28 and the first side interior surface 42, and the second lower interior surface 48 is shown adjoined between the second concave interior surface 30 and the second side interior surface 44, respectively.
(19) In the example illustrated, the sliding layer 18 is secured to the upper interior surface 26, the first and second concave interior surfaces 28, 30, the first and second lower interior surfaces 46, 48, and the first and second side interior surfaces 42, 44. The sliding layer 18 may include curved ends that are embedded within the cover 16 adjacent to the first and second side interior surfaces 42, 44, as illustrated.
(20) Various dimensions of the handrail 10 are illustrated in
(21) The present disclosure is directed to handrails that are generally compact in size. In some examples, the face height 52 may be less than about 8.0 mm, and the side width 54 may be less than about 7.5 mm. In some examples, the face height 52 may be less than about 7.5 mm, and the side width 54 may be less than about 7.0 mm. In some examples, the face height 52 may be between 7.0 and 7.5 mm, and the side width 54 may be between 6.5 and 7.0 mm. The carcass 12 may constitute at least 60% of the face height 52 or the side width 54 dimensions of the handrail 10, as illustrated.
(22) Vertical dimensions of the handrail 10 further include a handrail height 62, a slot height 64, and a lip height 66. Horizontal dimensions of the handrail 10 further include a handrail width 68, a slot width 70, a mouth width 72, and a stretch inhibitor width 74.
(23) Referring to
(24) Dimensions for a particular example of the handrail 10 are provided in Table 1. These dimensions are intended to be illustrative but non-limiting.
(25) TABLE-US-00001 TABLE 1 Dimension Reference mm face height 52 7.0 side width 54 6.5 handrail height 62 23.5 slot height 64 9.5 lip height 66 7.0 handrail width 68 72.0 slot width 70 59.0 mouth width 72 39.0 stretch inhibitor width 74 37.2
(26) The compact construction of the handrail 10 may reduce the power required to drive the handrail 10. For example, the handrail 10 may be approximately 30 to 40% less weight than a traditional handrail product that it is intended to replace. This reduction in weight will translate to lower power consumption on escalators, moving walkways and/or other transportation apparatus.
(27) Due to the compact sizing, the inventors have recognized that appropriate materials selection for the components is required to achieve satisfactory mechanical properties of the handrail 10.
(28) The carcass 12 may be formed of a first thermoplastic material, the cover 16 may be formed of a second thermoplastic material, and the sliding layer 18 may be formed of a fabric material. The first thermoplastic material of the carcass 12 is generally stiffer and harder than the second thermoplastic material of the cover 16, and serves to retain the mouth width 72 to provide a desired lip stiffness. The carcass 12 also serves to protect the stretch inhibitor 14, which in this case is formed of the cables 76, and the bond between the cables 76 and the first thermoplastic material of the carcass 12 may be improved by adhesive (not shown).
(29) For the carcass 12, polyester thermoplastic polyurethane may be implemented as the first thermoplastic material. In some examples, the first thermoplastic material of the carcass 12 may have a modulus at 100% elongation of between about 10 and 16 MPa and a hardness of between about 93 and 96 Shore A. In some particular examples, the first thermoplastic material of the carcass 12 may have a modulus of between about 12 and 15 MPa at 100% elongation and a hardness of between 94 and 95 Shore A. Exemplary specifications for the first thermoplastic material of the carcass 12 are provided in Table 2, which are intended to be illustrative but non-limiting.
(30) TABLE-US-00002 TABLE 2 Property Specification Units Comments Formulation Polyester TPU With anti- hydrolysis agent Hardness 93-96 Shore A ASTM D2240-00 Tensile 40 (minimum) MPa ASTM D412 Strength Ultimate 400 (minimum) % ASTM D412 Elongation Modulus @ 100% 10-16 MPa ASTM D412 Elongation Glass 20 (maximum) C. By differential Transition scanning calorimetry Processing Extrusion Melt Index 5-20 g 190 C./8700 g ASTM D1238
(31) For the cover 16, polyester thermoplastic polyurethane may be implemented as the second thermoplastic material. In some examples, the second thermoplastic material of the cover 16 may have a relatively low melt flow index, for example, on the order of between about 20 and 60 g under the conditions listed in table 3. In some particular examples, the second thermoplastic material of the cover 16 may have a melt flow index of between about 20 and 40 g under the conditions listed in table 3, and a broad molecular weight distribution so that a sharp melting point is avoided. Exemplary specifications for the second thermoplastic material of the cover 16 are provided in Table 3, which are intended to be illustrative but non-limiting.
(32) TABLE-US-00003 TABLE 3 Property Specification Units Comments Formulation Polyester TPU With anti- hydrolysis agent Hardness 83-87 Shore A ASTM D2240-00 Tensile 40 (minimum) MPa ASTM D412 Strength Ultimate 500 (minimum) % ASTM D412 Elongation Modulus @ 100% 4-6 MPa ASTM D412 Elongation Glass 20 (maximum) C. By differential Transition scanning calorimetry Processing Extrusion Broad molecular weight distribution Melt Index 20-40 g 210 C./3800 g ASTM D1238
(33) Exemplary specifications for the cables 76 of the stretch inhibitor 14 are provided in Table 4, which are intended to be illustrative but non-limiting.
(34) TABLE-US-00004 TABLE 4 Property Specification Units Type High Tensile Steel Cord, brass plated Construction Inner 3 mm 0.20 0.01 Outer 6 0.35 0.01 Twist 9.5 0.5 mm S 1 turn per 18.0 0.9 mm Z Linear 5.34 0.27 g/m Density Diameter 1.13 0.06 mm (in) Strength 1870 (minimum) N
(35) For the sliding layer 18, a woven spun polyester textile fabric may be used. In some examples, a three ply yarn may have residual shrinkage of at least 7.0% under the conditions provided in table 6. In some examples, the woven fabric may have a minimum warp shrinkage of at least 8.75%. These high shrinkage values may be required so that the fabric shrinks and tightens in the process. Use of yarns and fabrics with lower shrinkage (generally referred to as high tenacity) may result in the textile being stretched in the process and this stretch may be frozen or otherwise retained in the product after processing, thereby resulting in a higher modulus textile layer and a stiffer product. Exemplary specifications for the sliding layer 18 are provided in Tables 5, 6 and 7, which are intended to be illustrative but non-limiting.
(36) TABLE-US-00005 TABLE 5 STAPLE FIBERS Property Specification Units Test Method Fiber Type Polyester Staple Fiber 1.28 nominal Denier AATCC 20 Linear Density Staple Length 38-52 mm ASTM D5103 Melting Point 255 C. ASTM D3418 (Peak - by DSC)
(37) TABLE-US-00006 TABLE 6 YARN Property Specification Units Test Method Type Spun Polyester Yarn count 12 (50) Cotton ASTM D1907 Count (Tex) Anti-Static 22 Denier ASTM D1433 filament Yarn Twist 11.4 0.8 TPI ASTM D1433 Yarn 4.5 (minimum) kg/end ASTM D2256 Strength Yarn 20 % ASTM D2256 Elongation at Break Residual 7.0 (minimum) % ASTM 2259 Shrinkage (Method: Dry-Heat Exposure; 75 s at 200 C.) Number Yarns 3 (12/3 construction) in Standard Ply Anti-Static 3 standard yarns Ply (standard ply) Construction blended with 1 anti- static filament Ply Twist 6.0 + 1/0.5 TPI
(38) TABLE-US-00007 TABLE 7 WOVEN FABRIC Property Specification Units Test Method Weave Venetian Anti-static 20% warp yarns plied yarn spaced approximately addition every 5.sup.th warp end level Width 1448 13 mm Roll Length 360 10 m Maximum 648 mm O.D. of roll Warp Count 47 1 EPI (Ends) Weft (fill) 44 1 EPI Count (Picks) Fabric 607 34 g/m.sup.2 Weight Wide-Width 800 800 (minimum) N/cm Tensile, Warp Weft Gauge 1.02 0.08 mm Crimp, Warp 20 5 % Crimp, Weft 5 2 % Warp 8.75 (minimum) % Shrinkage Surface 1 10.sup.12 (maximum) /square ASTM D257 Resistivity
(39) The sliding layer 18 may be prepared generally in accordance with the pretreatment methods and apparatuses disclosed in International Publication No. WO/2009/033273. However, the inventors have developed the following pretreatment and testing procedure for the handrail 10: 1. Using a knife, cut a sample piece of fabric from a bulk roll to be tested. For example, the sample may have a length of 40 to 60 cm, and a width of no greater than 20 cm. 2. Using a pen, draw a plurality of lines of various lengths in both warp and weft direction for measuring. For example, 4 to 6 lines of various lengths from 50 mm to 10 mm. 3. Using a set of calipers, measure the length of each of the lines accurately to a tenth of a millimeter and record values. 4. Set two heated plates, arranged to provide heat to both sides of the fabric, at a temperature of 2003 C., and with a gap of approximately 3 mm between the plates. 5. Insert the fabric between the plates in the gap for 751 s. 6. Let sample cool for approximately 2 m after removal from the plates. 7. Using the calipers, measure each line again and record the results. 8. Calculate shrinkage percentage for each measured line according to equation (1).
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(41) Exemplary results of the pretreatment and testing procedure are provided in Table 8.
(42) TABLE-US-00008 TABLE 8 Sample Starting (mm) Shrunk (mm) % Change Width 138 125 9.42 Warp #1 105.15 95.12 9.54 Warp #2 100.88 90.54 10.25 Warp #3 100.28 88.61 11.64 Weft #1 100.99 91.3 9.60 Weft #2 103.05 93.06 9.69 Weft #3 101.44 91.12 10.17 Avg Warp % Change 10.48 Avg Weft % Change 9.82
(43) As noted in Table 7, shrinkage in the warp direction during the pretreatment should be at minimum 8.75% to yield a fabric that is both flexible and strong. The inventors have found that if the fabric used for the sliding layer does not shrink in the warp direction by at least 8.75% during pretreatment, the performance of the handrail 10 in dynamic testing may be compromised. Shrinkage in the weft direction has been found to be less important on the mechanical properties of the resulting handrail 10.
(44) The handrail 10 as disclosed herein may exhibit enhanced mechanical properties.
(45) Lip stiffness refers to the force required to open the handrail lip apart using two mechanical jaws seated inside the handrail lip. This is one particular characteristic of the handrail 10 that may be important, as it is a safety consideration that relates to the ability of the handrail to resist being pulled off of its guide. Referring to
(46) The handrail 10 may also be relatively good at maintaining straightness along its length under tension. Referring to
(47) Another characteristic that may be measured is the force required for forward bending. A nominal force of 20 N may be required to bend an 800 mm length of the handrail 10 90 over a jig with radius of 305 mm, with a maximum lip dimensional change while bent being +3/1 mm. For backward bending, a nominal force of 25 N may be required to bend a 1700 mm length of the handrail 10 90 over a jig with radius of 610 mm, with a maximum lip dimensional change while bent being +3/1 mm.
(48) Furthermore, there is a permitted bending radii that allows the handrail 10 to bend and flex with relatively smooth transitions. For a reverse (negative) bend, the handrail 10 may exhibit a 380 mm minimum bending radii. For a forward (positive) bend, the handrail 10 may exhibit a 180 mm minimum bending radii.
(49) The handrail 10 may be manufactured generally in accordance with the extrusion methods and apparatuses disclosed in International Publication No. WO/2009/033270. However, after extruding and cooling the handrail 10, it may be desirable store the handrail 10 in a reverse bend orientation. Referring to
(50) Storing and aging the freshly extruded handrail 10 in this manner places the thermoplastic components furthest from the cables 76 and the neutral axis and under slight tension. This is built in to the structure as the thermoplastic materials reach their final properties and shape while aging on the reel for an extended period of time, for example, 48 hours or more. In some examples, the handrail 10 in the reverse bend orientation may age on the reel for 7 days or more. This built in stress essentially makes the handrail 10 below the neutral axis longer so that the effects of thermoplastic and slider fabric shrinkage are negated to some degree. If the handrail 10 is stored rolled in the forward direction, the handrail 10 may have a permanent forward set so that it may be difficult to handle, more force may be required to bend it in the reverse direction, and it may be more prone to collapsing while bending. In contrast, when the handrail 10 is aged rolled in the reverse orientation, it may come off the reel and lay flat making handling easier, it may require less force to bend in reverse, and may be less prone to kinking. This may be important with a compact product as the thinner cross section may be more prone to collapse and kinking.
(51) Referring to
(52) Referring to
(53) In the example illustrated, the sliding layer 218 includes a planar portion 220 and first and second upstanding edge portions 222, 224. The upstanding edge portions 222, 224 are shown to have curved ends 226, 228, respectively, that are embedded within the cover 216.
(54) In the example illustrated, the carcass 212 is on the sliding layer 218 and centrally disposed between the first and second upstanding edge portions 222, 224. The carcass 212 is shown to be generally rectangular, and has rounded upper corners arranged between first and second edges 230, 232 and a top surface of the carcass 212.
(55) The cover 216 covers the carcass 212 and extends between the first and second upstanding edge portions 222, 224. In the example illustrated, the cover 216 contacts the carcass 212 at an interface to form a continuous body. The cover 216 is shown to include first and second bottom surfaces 234, 236, which are in contact with the planar portion 220 of the sliding layer 218 between the upstanding edge portions 222, 224 and the edges 230, 232 of the carcass 212. The cover 216 further includes first and second side surfaces 238, 240, which are in contact with the upstanding edge portions 222, 224 of the sliding layer 218, respectively.
(56) In the example illustrated, the cover 216 includes an upper surface having first and second raised portions 242, 244 and a valley 246 between the first and second raised portions 242, 244. The valley 246 defines a concave shape between the first and second raised portions 242, 244.
(57) In the example illustrated, the stretch inhibitor 214 is formed of a plurality of longitudinal cables 248, which are shown disposed along a central plane within the carcass 212.
(58) Various dimensions of the intermediate handrail product 210 are illustrated in
(59) In the example illustrated, the first and second raised portions 242, 244 are shown offset inwardly in relation to the edges 230, 232 of the carcass 212. In other words, the valley width 254 is substantially less than the carcass width 252.
(60) Dimensions for a particular example of the intermediate handrail product 210 are provided in Table 9. These dimensions are intended to be illustrative but non-limiting.
(61) TABLE-US-00009 TABLE 9 Dimension Reference mm product width 250 92.0 carcass width 252 67.0 valley width 254 62.0 raised height 256 10.5 central height 258 8.2 edge height 260 7.25 carcass height 274 6.0
(62) As mentioned above, the handrail 10 may be manufactured generally in accordance with the extrusion methods and apparatuses disclosed in International Publication No. WO/2009/033270. The intermediate handrail product 210 may be an extrudate product that is extruded out of a die assembly (not shown), and requires further processing to obtain the final, desired profile of the handrail 10 as shown in
(63) Referring to
(64) In the example illustrated, extending longitudinally along the upper section 266 is a bore 268 into which opens into slots 270. A transverse port 272 opens into the bore 268. The port 272 is connected to a vacuum source. This maintains a vacuum within the bore 268, for example, in the range of 8 to 12 inches of mercury. The purpose of the vacuum is to ensure that the sliding layer 218 closely follows the mandrel 262. The level of the vacuum may be determined by that necessary to ensure good accurate following of the mandrel 262 profile, while at the same time not being too high so as to create excessive drag. If a high degree of vacuum is used, then a higher tension may have to be applied to pull the handrail along the mandrel, and this may stretch the sliding layer 218. The exact length of the mandrel 112 will depend upon the intended production rate.
(65) As the intermediate handrail product 210 is guided along the mandrel 262, outer edges of the intermediate handrail product 210 are dropped downwardly, so as to have the effect of lessening the height of the first and second raised portions 242, 244 (
(66) As the intermediate handrail product 210 is guided along the mandrel 262, the upstanding edge portions 222, 224 of the sliding layer 218 may be continuously supported along the mandrel 112 and progressively dropped downwardly until they are generally horizontal, and then continued to be turned inwardly to form the final C-shaped profile of the handrail 10 (
(67) The temperature conditions in the die assembly may be such that, on leaving the die assembly, the thermoplastic materials of the intermediate handrail product 210 are still molten. Along the mandrel 262, the sliding layer 218 remains solid throughout the forming process and serves as the contact surface, and the molten thermoplastic materials may be untouched. The mandrel 262 may be heated or cooled in order to maintain the intermediate handrail product 210 at an ideal forming temperature. Depending on the production speeds at which the extrudate travels across the mandrel 262, cooling may in fact be necessary to maintain the mandrel at an appropriate temperature, for example, 50 C.
(68) At the end of the mandrel 262, the finished profile of the handrail 10 may be formed, and the thermoplastic materials may still not be properly solidified. To cool and solidify the thermoplastic materials, the handrail 10 may be passed into a cooling unit (not shown). A plurality of rollers (not shown) may also be implemented to cool and effect the skinning of the exterior of the handrail 10, the removal of die lines, and/or additional shaping of the exterior surface of the handrail 10.
(69) It will be appreciated that terms used herein to convey geometrical or mathematical relationships need not be construed with absolute precision. For example, the terms concave and convex as used herein need not be interpreted to mean structures having a curved surface that is exactly circular. These terms and other terms herein may be interpreted with some flexibility, without strict adherence to mathematical definitions, as will be appreciated by persons skilled in the art.
(70) While the above description provides examples of one or more apparatuses or methods, it will be appreciated that other apparatuses or methods may be within the scope of the accompanying claims.