Passenger conveyor balustrade

A balustrade for use with passenger conveyors including a second deck member bent to assume an arcuate shape at landings, and having a U-shaped cross-section adapted to be opened facing the center of the arc, and deformation preventing strips formed by bending the second deck member adjacent its opening which defines an inner periphery of the arcuate-shaped sections of the second deck member.

LIST OF PRIOR ART REFERENCE (37CFR 1.56 (a)) 
U.S. Pat. No. 3,321,059 Knoepel May 23, 1967, 198-16 
U.S. Pat. No. 3,353,650 Schroeder et al Nov. 21, 1967 198-16 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a balustrade for use with passenger conveyors 
such as escalators, electrically operated passageways and the like and, 
more particularly, to a balustrade which is formed of stainless steel 
sheets. 
2. Description of the Prior Art 
Passenger conveyors have spread widely as fixtures which are indispensable 
to a building as a means for satisfying the needs of persons who utilize 
the building. In recent years, a variety of demands have been put forward 
for industrial designs of balustrades. As is well known, the balustrade 
constitutes a major part of a designed body in the passenger conveyor, and 
it is generally recognized by the parties concerned that whether the 
balustrade has an attractive industrial design or not is a major selling 
point in respect of making a discrimination among room designs. 
As described in U.S. Pat. Nos. 3,321,059 and 3,353,650, the balustrade 
includes stationary members except for an endless series of steps adapted 
to convey passengers thereon, and moving parts such as handrails. As 
described above, each balustrade includes, as main components thereof, a 
main deck member upon which handrail is mounted, a lower deck member and a 
glass panel, all of which constitute an object for industrial design. It 
is conventional to form the main and lower deck members by extruded 
material of aluminum alloy, of which surfaces have been subjected to 
alumite treatment. 
Aluminum alloy material has been widely used for the main and lower deck 
members of a balustrade since it is advantageous in its formability into 
substantially complex shapes. However, the use of this material has a 
disadvantage in that the manufacturing cost thereof continues to be 
increased due to high electric power consumption and the raw material 
therefor tends to be reduced. However, what is more significant than the 
high manufacturing cost is the fact that aluminum alloy material is 
relatively soft (as compared to such metallic materials as steel) to be 
readily marred. This presents a serious problem in which the respective 
members of balustrade present scratches and impressions on the inner sides 
thereof facing the steps after the members have been contacted by a large 
number of passengers during several years of operation. Thus such 
passenger conveyors present an unsightly appearance. Particularly in the 
case of passenger conveyors installed in underground markets, corrosion of 
the material of the balustrades caused by underground water adds to 
deterioration of the industrial design of the balustrades. 
Therefore, stainless steel sheets have begun to be used in place of 
aluminum alloy material, which sheets are superior to the latter in price 
stabilization, hardness and anticorrosive resistance. However, the use of 
stainless steel for balustrades raises the technical problem of the 
material being deformed when worked to bend the same. Since this problem 
has not been solved satisfactorily, the practice of using a stainless 
steel sheet has not yet become popular. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a balustrade for 
passenger conveyors which is highly productive and obviates the 
aforementioned problem of deformation upon bending. 
The object of the present invention can be accomplished by a balustrade for 
use with passenger conveyors including a handrail guide for guiding a 
handrail adapted to be moved in synchronism with a endless series of 
steps, a first deck member and a second deck member connected to the first 
deck member and having a U-shaped cross-section with its opening facing 
the opposite side of the handrail, each of said first and second deck 
members being bent to assume an arcuate shape at landings, the improvement 
comprising deformation preventing strips provided adjacent the opening 
about the arcuate-shaped sections of the second deck member and bent 
inwardly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As shown in FIG. 1, the passenger conveyor comprises balustrades each 
including stationary members except for an endless series of steps 1 
adapted to convey passengers thereon, and a handrail 2 disposed above the 
steps. The stationary members comprise mainly a main deck member 3 for 
supporting the handrail 2, a lower deck member 4 and a balustrade glass 
panel 5, all of which are objects of industrial design. A material for 
balustrades is, first of all, required to have a good bending workability 
since the contour of balustrade consists of concave or U-shaped curve, 
T-shaped terminal curve and unique, streamlined arc. 
Referring now to FIG. 2, the prior main deck member 3 made of aluminum 
alloy has a glass panel 5' fitted thereinto at the lower portion thereof 
and has a guide 2a secured thereto at the upper end portion thereof by 
means of bolts 6, which guide guides the handrail 2. The configuration in 
section of the main deck member 3 is conventionally determined such that 
portions of the main deck member 3 are thickened at areas where wrinkles 
tend to be produced (as at 3a in FIG. 2), are thinned at areas where 
wrinkles are hard to be produced (as at 3c in FIG. 2), and are in the form 
of decorative line (3b). In the prior art, attempts have been made to meet 
the requirements of compensating for the lack of workability of the 
material and increasing the attractiveness of the decorative design as 
aforementioned. 
In FIG. 3, there is shown a main deck member formed of stainless steel 
which have come to attract attention in recent years. A thin sheet of 1 to 
3 millimeter in thickness t is subject to bending by means of a press 
brake to provide a main deck member having a desired cross-sectional 
shape. Therefore, it is conventional neither to provide any variation in 
thickness of the material nor to provide a decorative line. As it is, the 
main deck member 3 is produced by separately forming a first U-shaped deck 
portion or member 7a and a second U-shaped deck portion or member 7b, and 
then secure them together by means of bolts 8 when assembled. 
Although the deck portions or members 7a and 7b lack variety in industrial 
design (such as the use of a decorative line) and it is troublesome to 
join the two deck portions or members 7a, 7b together by means of bolts, 
there has been an increasing demand for deck members made of stainless 
steel because they are resistant to scratches, are highly durable, and 
present deep gloss thereon which is favored by many people. 
The manner in which a balustrade deck member made of stainless steel are 
subjected to bending will now be described by referring to the deck member 
7a by way of illustration. 
As shown in FIGS. 4 to 7, opposite end portions a and b are subject to 
tension in the directions of arrows A and B with the deck member 7a faced 
inwardly, so that an outer peripheral surface g.sub.1 may have radius or 
curvature R.sub.1 and an inner peripheral surface g.sub.2 may have radius 
of curvature R.sub.2. In this case, reaction forces against the tensile 
forces in the directions of arrows A and B are distributed over 
substantially all the area of the inner peripheral portion as designated 
by an arrows c, and the outer peripheral surface g.sub.1 is elongated as 
indicated by the arrows D. As a result, the portion of the deck member 7a 
disposed inwardly of a neutral axis L, as shown in FIG. 6, begins to 
contract as indicated by an arrows F (FIG. 5). Such phenomenon is 
physically natural, but causes disadvantages as presently to be described 
when this type of thin stainless steel sheet is bent. 
More specifically, the aforementioned contraction indicated by arrows F 
manifests itself as large wrinkles on the inner peripheral surfaces 
g.sub.2, as shown in FIG. 7. Therefore, the flange portions of the deck 
member 7a extending over a width of W are displaced laterally a distance 
S.sub.1 (FIG. 6). It will be appreciated that much work is required to 
correct the deformation of the deck member 7a into a regular shape. The 
wrinkles S are, of course, greatly related to the position of the neutral 
axis L from the viewpoint of strength of materials, and can not be avoided 
due to the shape of the deck member 7a, as shown in FIG. 6, in which the 
neutral axis L is spaced a short distance n from the outer peripheral 
surface g.sub.1 and a radius of curvature R3 at the neutral axis L is 
close to radius of curvature R1 (&gt;R3.apprxeq.R2) of the outer peripheral 
surface g.sub.1. Therefore, it will be apparent that in order to eliminate 
wrinkles S or displacement S.sub.1, the neutral axis L should be 
positioned near the inner peripheral surface g.sub.2 where wrinkles tend 
to occur. 
As an alternative measure for preventing wrinkles S from being produced, 
that portion of the deck member 7a which may produce wrinkles can be 
thickened so as to absorb wrinkles therein, as shown in FIG. 2. However, 
such measure cannot go well in cases where stainless steel sheets of a 
uniform thickness are subject to bending to form deck members 7a. Thus, 
their has been a significant problem in the preventing of wrinkles in 
balustrades made of stainless steel. 
FIGS. 8 and 9 show one embodiment of the invention. In the drawings, a 
handrail (not shown) and a balustrade glass panel 5 are similar in 
construction to those of the prior balustrade. According to the present 
invention, a deck member 9a is substantially U-shaped in cross section and 
includes deformation preventing plates 10, each of which extends a 
distance M.sub.1 inwardly along an inner peripheral surface g.sub.3 
(corresponding to g.sub.2 of the prior deck member). The deformation 
preventing plates 10 are formed upon bending in a press brake when a 
stainless steel sheet is formed into a substantially U-shaped body. The 
distance over which each deformation preventing plate 10 extends along the 
surface g.sub.3 is 1.5 or more, preferably 2 to 4 times the thickness t of 
the sheet. The deformation preventing plates 10 increase the flexural 
rigidity of the inner peripheral surface g.sub.3 (as seen from FIG. 9, the 
cross-sectional area of the inner peripheral surface portion g.sub.3 is 
greater than that of the inner peripheral surface portion g.sub.2 in FIG. 
6), and the neutral axis l is displaced substantially toward the inner 
peripheral surface g.sub.3 to be positioned a distance N from the outer 
peripheral surface g.sub.1 where N is larger than n (N&gt;n), and the radius 
of curvature is R4 at the position of the neutral axis l. 
(R1-R4.apprxeq.N). It will be apparent that wrinkles are difficult to be 
produced. In addition, the inner peripheral surface portion g.sub.3 is 
increased in flexural rigidity to be effective in eliminating wrinkles. 
From the foregoing description, it will be appreciated that the present 
invention provides deck members which facilitate bending work and 
facilitate production thereof. Moreover, the invention is advantageous in 
that problems associated with scratches and corrosion can be solved so as 
to render a passenger conveyor durable. 
It is to be understood that the invention is not limited to the specific 
shape of the deformation preventing plate of the deck member shown and 
described hereinabove. For example, the plate may assume the shape as at 
11 in FIG. 10, in which the plate is turned down to be brought into 
contact with the flange portion of the deck member 9a. The invention 
essentially resides in the provision of a deck member which is U-shaped in 
section and is provided at the inner peripheral surface thereof with 
deformation preventing plates. The shape and the width of the deformation 
preventing plate may be selected as desired. The deformation preventing 
plate can be applied to the deck member as illustrated, but also to all 
the members adapted to be subject to bending work. The material used for 
forming the deck members of the balustrade is not limited to stainless 
steel sheets, but may be common steel sheets.