US3463290A - Handrail belt for escalator - Google Patents

Description

Aug. 26, 1969 Filed Jan. 24.l 1967 TAKASHI TAJIMA HANDRAIL BELT FOR ESCALATOR 2 Sheets-Sheet 1 Aug. 26, 1969 TAKASHI TAJIMA 3,463,290

HANDRAIL BELT FOR ESCALATOR Filed Jan. 24, 1967 f 2 Sheets-Sheet 2 United States Patent O 3,463,290 HANDRAIL BELT FOR ESCALATOR Takashi Tajima, Sagamihara, Japan, assignor to Mitsubishi Denki Kabushiki Kaisha, Tokyo, Japan Filed Apr. 24, 1967, Ser. No. 633,002 A Claims priority, application Japan, Apr. 27, 1966,

U.S. Cl. 198-16 4 Claims ABSTRACT OF THE DISCLOSURE This disclosed belt is of a generally C-shaped cross section and comprises a plurality of cotton sailcloth webs bonded together in a stack of laminations with a bonding agent, and a dressing rubber layer secured to the outer surface of the stack. A tensioning member is sandwiched between each pair of adjacent laminations on the central ilat portion of the C and preferably on the lower half thereof and extends throughout the length of the belt. The tensioning member is composed of an array of textile cords juxtaposed widthwise of the belt, and each cord is prepared by paralleling and twisting any suitable inorganic yarn or yarns such as glass filaments high in tensile strength and low in elongation and any suitable organic yarn or yarns such as rayon filaments easily wettable with a bonding agent involved and highly flexible in a proportion of `from 9:1 to 5:5. The resulting belt is very low in elongation and can be longitudinally bent along a circle having a radius as small as 220 mm. Further there is no fear that the tensioning members peel olf from the adjacent webs during service.

This invention relates to improvements in a handrail belt for use in an escalator system and more particularly to tensioning members embedded in such a handrail belt.

The conventional type of handrail belts for use in escalator systems has been generally composed of a core member comprising a plurality of sailcloth Webs made of a cotton fabric or the like and bonded together into a stack of laminations with any suitable bonding agent, tensioning members interposed between adjacent laminations to prevent any longitudinal elongation of the belt, and a dressing layer of rubber material covering the outer surface of the stack. The tensioning member might be formed of any suitable organic textile cord relatively high in tensile strength or any suitable thin metallic wire rope. The organic textile cords were excellent in that they were easily wettable with the associated bonding agent and highly flexible but they were disadvantageous in that they were insucient to prevent any longitudinal elongation of the belt. On the other hand, the metallic wire ropes were effective for preventing such elongation but they were disadvantageous in that they impeded the fllexibility of the belt as compared with the organic textile cords. Sometimes the wire ropes might be broken during service resulting in the end portions of the broken wire ropes projecting externally beyond the dressing rubber layer.

In is, accordingly, a general object of the invention to eliminate the abovementioned disadvantages.

It is another object of the invention to provide a new and improved handrail belt for use in an escalator system high in flexibility, substantially free from any longitudinal elongation and reliable in operation.

It is a more special object of the invention to provide a new and improved handrail belt especially suitable for use in the latest type of escalator systems tending to decrease a bending radius of the belt as moved just past 3,463,290 Patented Aug. 26, 1969 either of the upper and lower newel portions thereof to magnitude as small as possible.

The above cited objects and other objects Which will become apparent as the description proceeds are accomplished by the invention providing a handrail belt for use in an escalator system, incl-uding a core member comprising a plurality of sailcloth webs bonded together into a stack of laminations with a bonding agent and a layer of rubber material covering the outer surface ofthe stack, the belt being of a generally C-shaped cross section, wherein a tensioning member is sandwiched between each pair of adjacent laminations on a predetermined portion of the belt and extends throughout the length thereof, and wherein the tensioning member comprises an array of lengths of a textile cord juxtaposed widthwise of the belt, and including an inorganic fibrous material high in tensile strength and low in elongation and an organic fibrous material high in both adhesiveness to the bonding agent involved and ilexibilty in a proportion of from 9:1 to 5:5 and in paralleled and twisted yarn state.

Preferably, the tensioning members may be disposed only in a relatively flat, central portion of the C.

Advantageously, the inorganic brous material may be glass filaments while the organic fibrous material may be rayon filaments.

The invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side elevational view of an escalator system incorporating the teachings of the invention;

FIG. 2 is a cross sectional view of a handrail belt constructed in accordance with the teachings of the invention;

FIG. 3 is a fragmental plan view of -a tensioning member illustrated in FIG. 2;

FIG. 4 is a fragmental perspective view, partly in section, illustrating how both side ears of a handrail lbelt is locally raised outwardly in the case that portion of the belt traveling past a newel portion of an escalators balustrade has a bending radius smaller than that previously used with parts broken away; and

FIGS. 5a to c inclusive are diagrammatic views useful in explaining the results of the invention.

Referring now to FIG. 1 there is illustrated an escalator system to which the invention is advantageously applicable. An arrangement illustrated comprises a supporting frame 10 having disposed therein a moving stairway and a drive (not shown), a balustrade on each side thereof including a plurality of balusters 12 planted on the upper edge of the supporting frame 10 and a plurality of cover panels 14 secured to the balusters 12, and a handrail belt 16 in the form of an endless belt adapted to be driven by the drive to travel along the -balustrade 12-14. The abovementioned components are of the conventional construction except for the belt 16 and need not be described here in detail. [It is sufficient to be said that the escalator system is of the latest design by which the upper and lower newel portions of the balustrade have the respective bending radii as small as possible.

Referring now to FIG. 2, there is illustrated, in cross section, a handrail belt constructed in accordance with the teachings of the invention. The handrail belt generally designated by the reference numeral 16 is in the form of an endless belt having a generally C-shaped cross section and includes a central ilat portion 18 and a curved end portion 20 or 20 forming each side portion of the belt 16 and commonly called an ear. As shown in FIG. 2, the belt 16 comprises a plurality of sailcloth webs 22 made, for example, of a cotton fabric and bonded together into a stack of laminations with any suitable bonding agent 24 such as neoprene rubber, a tensioning member, generally designated by the reference numeral 26, in the form of a layer sandwiched between each pair of adjacent Webs 22 forming the lower half of the central at portion 18 and extending throughout the length of the belt '16. The belt 16 further is provided on the outer surface with a dressing layer 28 of any suitable rubber material such as a synthetic rubber sold under the trademark Hyparon by E. I. du Pont de Nemours and Company, Wilmington, Del., U.S.A. The same bonding agent as that used to bond the webs 22 may be used to secure the tensioning member 26 to the adjacent webs 22 and also secure the dressing layer 28 to the outer surface of the stack.

The tensioning member 26 is composed of a textile cord consisting of an inorganic fibrous material high in tensile strength and low in elongation and an organic fibrous material easily wettable with the bonding agent involved and high in flexibility. Preferably the inorganic fibrous material is a glass yarn and the organic fibrous material is a rayon yarn. A proportion of amount of the inorganic material to the amount of the organic material may preferably range from 9 to l to 5 to 5. Yarns made of such inorganic and organic fibrous materials in a proportion just specified are paralleled and twisted into a cord. A plurality of lengths of the cord thus produced are juxtaposed as warp yarn 30 and woven with lengths of weft yarn 32 of any suitable material into a cord fabric as shown in FIG. 3. Therefore it will be understood that the resulting tensioning member has a high tensile strength, a low elongation and a high flexibility as well as being capable of being wetted with the bonding agent involved thereby to be firmly attached to the adjacent webs after the bonding agent has been cured.

If desired, a plurality of lengths of the cord alone may be disposed in a form of a layer. Alternatively they may be bonded into a layer with any suitable bonding agent.

According to the teachings of the invention, the tensioning members 26 should be disposed in the central at portion 18 of the belt 16.

The reasons for this will now be described in conjunction with FIG. 4 and FIGS. 5a to c inclusive. If the belt has its core composed of a single material, the neutral axis about which the belt is longitudinally bent will be in its position illustrated at line X1-X1 in FIG. 5a. Under these circumstances, if the particular portion of the belt 16 enters its position where it has applied thereto a longitudinally bending force, or if it travels just past a newel portion of the associated balustrade as designated by the reference character A in FIG. 4 then the opposed ears 20 and 20 thereof will be subjected at the free edges to a high internal compressive force in the bending direction thereby to be locally raised or ridged outwardly in the direction of bending radius as designated by the reference character B in FIG. 4. The stress resulting from the compressive force is concentrated on the weak portion of the free ear edge until the free ear edge portion is locally raised or ridged as shown in FIG. 4. Further the raised belt portion may be damaged due to a fatigue by its bending.

On the contrary, the provision of the tensioning members 26 disposed in the central flat portion 18 of the belt 16 as in the invention causes the neutral axis as above described to change its position from line Xl-Xl illustrated in FIG. a to line X2-X2 illustrated in FIG. 5b. Under these circumstances, when the belt 16 is just passed through its position where it has applied thereto a longitudinal bending force, then an internal stress produced in each ear by that force will change the coniguration of the belt as a whole as shown at solid line in FIG. 5c. In other words, both ears and 20 expand outwardly as shown at solid line in FIG. 5c to be prevented from being locally raised outwardly due to the internal stresses leading to no occurrence of the objectional phenomenon such as shown in FIG. 4. The lower in elongation the material for the tensioning members 26 will be as compared with the material for the ears 20 and 20 the greater i the effect just described. Iln FIGS. 5a to c inclusive the lowermost horizontal line designates a central axis about which the belt is longitudinally bent with a bending radius of R.

It has been found that, for the best results the tensioning members 26 are preferably disposed only in the lower half of the central llat belt portion. The tensioning members 26 disposed in the upper half of the central ilat belt portion 18 leads to a decrease in exibility of the belt 16.

Any Iorganic fibrous material such as rayon filaments relatively high in elongation are not suitable for exhibiting the same result as that above described and do not stand use particularly when the belt has a bending radius of 340 mm. or less. On the other hand, the use of the tensioning members such as metallic wire ropes low in elongation may be expected 'to exhibit the abovementioned effect. However the use of a metallic wire rope in a position where a bending radius is small adversely affects the overall exibility of the belt and may have a fear of breaking the belt.

As an example, six cotton sailcloth webs superposed each other with two tensioning members interposed between the lowermost three webs and a dressing layer made of Hyparon (trademark) was plated on the uppermost web. The assembly thus prepared with a bonding agent neoprene rubber was molded and vulcanized at a temperature of 160 C. under a pressure of 35 kgJcm.2 for 20 minutes into a handrail belt having a cross section similar to that shown in FIG. 2. The tensioning member was formed of a cord fabric including a textile cord as a Warp consisting of glass and rayon yarns in a proportion of 8 to 2 paralleled and twisted and a. cotton yarn as a weft. The cord had a tensile strength of from 17 to 18 kg./mm.3 at a :tension speed of mm./min. Specimens cut from the belt thus produced are called Specimen A hereinafter.

The precedute just described was repeated excepting that the tensioning member was formed of a cord fabric including twisted rayon yarns alone as a warp and cotton yarn as the weft. The cord had a tensile strength of from 16 to 17 kg./mm.2 at a tension speed of 150 mm./min. In this way, control specimens B were produced.

The specimens A and B were tested to determine various properties. The lfollowing table illustrates the relationship between the tensile force and elongation measured at room temperature and at a loading rate of 20 kg./min.

TABLE-RELATIONSHIP BETWEEN TENSILE FORCE AN D From preceding table it will be appreciated that the present belt is low in elongation and has a very low elongation particularly with the higher tensile tforces as compared with the control belt.

Also the adhesive strength or peel strength at room temperature of the tensioning member with respect to the adjacent sailcloth web had been determined to have a magnitude of from 5 to 6 kg./ cm. for Specimens A and a magnitude of from 5.5 to 7 kg./cm. for the control Specimens B.

A minimum radius above which the belt can be longitudinally vbent along a circle without the belt ears locally raised outwardly was 220 mm. for the present belt and 340 mm. for the control belt. These tests were conducted at room temperature.

From the foregoing it will be appreciated that the tensioning members disposed only in the central at portion of the handrail belt according to the teachings of the invention do not impede the flexibility of the resulting multilayer belt and are high in adhesion to the adjacent cotton webs as well as being sufficiently effective for substantially preventing an elongation of the belt. Therefore, there is no `fear that the adjacent layers forming the belt may peel off from each other. Further the present belt can be satisfactorily used with the latest type of escalator system wherein a radius with which the belt as traveling past either of the upper and lower newel portions of the escalators balustrade is longitudinally bent is made small as previously described.

While the invention has been described in conjunction with a few preferred embodiments Ithereof it is to be understood that it is not limited to the arrangement illustrated and that various changes in the details of construction and the arrangement and combination of parts may be resorted to without departing from the spirit and scope of the in- Ivention.

What I claim is:

1. A hand rail belt for use in an escalator system including a core member comprising a plurality of cloth webs bonded together into a stack of laminations with a bonding agent; a layer of rubber material covering the outer surface of the stack, the belt being of a generally C-shaped cross section; an integral tensioning member interposed between and adjacent to adjacent ones of said laminations in the lower half of the central flat portion of the belt to extend throughout the length thereof, comprising an array of lengths of textile cord juxtaposed widthwise of the belt and woven with a weft yarn into a cord fabric, said tensioning member including an inorganic fibrous material high in tensile strength and low in elongation and an organic fibrous material high in both adhesiveness to the bonding agent and flexibility in a proportion of inorganic to organic material of from 9:1 to 5:5.

2. A hand rail as in claim 1, wherein said cloth laminations are uniformly spaced throughout substantially the entire width of said rail.

3. A hand rail as in claim 2, wherein said cloth laminations are bonded with layers of neoprene rubber.

4. A handrail belt as claimed in claim 1, wherein said inorganic fibrous material is a glass yarn and said organic fibrous material is a rayon yarn.

References Cited UNITED STATES PATENTS 2,448,782 9/ 1948 Davis 161-93 2,669,339 2/ 1954 Hansen 198-16 FOREIGN PATENTS 955,479 4/ 1964 Great Britain.

RICHARD E. AEGERTER, Primary Examiner

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