Transport installation, step member equipped with protective projecting step edges, and method of protecting lateral edges of a transport installation

In transport installations, particularly escalators, a latent danger of jamming exists between a moving step and the stationary skirt panels mounted laterally near the steps, above all for flimsy footwear. In the escalator step according to the invention, throughout a danger zone coinciding with the precursive level run of an escalator step run, a tread edge member laterally adjacent each step is positively shifted upwards by a certain amount. In a return run of the escalator step run, this tread edge member is held by a spring force in a position lying flush with a tread surface of the step. The relative motion occurring between each step and a traction member for forming a constantly horizontally running tread surface of the step in the precursive level run of the escalator step run, results also in an angular displacement between an escalator step body of the escalator step and a cam or crank arm connected with a pivot axis of the traction member. This angular displacement is exploited for actuating the lateral tread edge members in that an entrainment pin or crank pin mounted on the cam or crank arm actuates a rocker arm pivoted on the step body. In turn the rocker arm appropriately moves the tread edge member upwards and downwards.

BACKGROUND THE INVENTION 
The present invention broadly relates to passenger transport installations, 
especially escalators and, more specifically, pertains to a new and 
improved construction of an escalator step and also pertains to a new and 
improved method of protecting lateral edges of transport installations. 
In the context of this disclosure, the term escalator step refers to any 
support member for the transport of passengers or articles by means of a 
sequential train of such support members. A preferred application of the 
inventive step member is in passenger escalators. 
In its more particular aspects, the invention relates to an escalator step 
of an escalator step run comprising a plurality of escalator steps and two 
continuous transporting or traction means, which escalator step run is 
guided between two stationary skirt panels and which escalator step 
possesses tread edge members protruding or projecting beyond, i.e. above, 
the tread surface on both lateral sides. 
It is known that in escalators, a latent danger of jamming prevails, above 
all for flimsy footwear, between the moving step and the stationary skirt 
panel. Jamming accidents usually arise then when a passenger stands 
laterally so close to a limit of the tread surface of the step that a shoe 
brushes against the stationary skirt panel mounted laterally of the step. 
In addition to the thus resulting friction counter to the direction of 
travel, at the locations where the step risers either retract or deploy, 
there arises a relative motion transverse to the direction of travel 
resulting in friction transverse to the direction of travel. This motion 
and the therewith associated friction arise at either the upper or the 
lower transition or landing region of the escalator, depending on the 
direction of travel. This motion can draw flimsy footwear in between the 
moving step and the stationary skirt panel. 
In other words, the present invention relates to a step or step member for 
an escalator in which an escalator step run comprising a plurality of such 
step members and two continuous traction means is guided between two 
stationary skirt panels. The step member comprises a step body having a 
tread surface, two lateral sides and at least one lateral side wall. The 
step body is provided with a respective tread edge member arranged at each 
of the two lateral sides and projecting above the tread surface. 
Expressed in a different manner, the step or step member of the present 
invention is for a transport means, especially passenger transport means 
such as escalators and moving sidewalks or walkways. The step member 
comprises a step body having a substantially horizontal tread surface and 
two lateral walls. The step body is provided with a tread edge member 
arranged at least at one of the two lateral walls for performing extension 
and retraction motions relative to the step body such that each tread edge 
member projects above the substantially horizontal tread surface in an 
extended position thereof and such that each tread edge member is 
substantially flush with the substantially horizontal tread surface in a 
retracted position thereof. 
The present invention also relates to a transport means, especially a 
passenger transport means such as an escalator or a moving sidewalk or 
walkway. The transport means comprises continuously circulating traction 
means having a predetermined path of travel. The continuously circulating 
traction means comprise chain wheel axles extending transverse to the 
predetermined path of travel and each having two ends. The continuously 
circulating traction means comprises link members extending substantially 
parallel to the predetermined path of travel and each having a first end 
and a second end. A respective link member of the link members is attached 
to each end of the two ends of each chain wheel axle and fixed against 
rotation relative thereto. 
The method of the present invention is for protecting the lateral edges of 
transport means comprising step members and continuous traction means 
having discrete link members, especially passenger transport means such as 
escalators and moving sidewalks or walkways. The method comprises the 
steps of providing each step member with a tread edge member arranged at 
least at one of two lateral walls of the step member for performing 
extension and retraction motions relative to the step member such that 
each tread edge member projects above the substantially horizontal tread 
surface in an extended position thereof and such that each tread edge 
member is substantially flush with the substantially horizontal tread 
surface in a retracted position thereof. 
Various developments have become known by means of which it has been tried 
and is still being tried to obviate the danger set forth above. One of 
these developments which is known from the U.S. Pat. No. 4,236,623, 
granted Dec. 2, 1980 consists in raising the lateral portions of the step 
tread or surface by wedging a plastic profile or rib into the outermost 
two grooves of the tread so that this portion of the step is rendered 
uncomfortable to escalator users such that they will stand on the planar 
tread surface adjacent this raised rib. The wedged plastic profile or rib 
additionally possesses a gentle inclination on the surface facing away 
from the skirt panel. A shoe nevertheless brought to bear on this location 
also assumes a slight inclination or canting. If the shoe also 
simultaneously bears against the skirt panel, a portion of the ensuing 
horizontal force will be taken up by the raised step edge and the friction 
on the skirt panel and thus the danger of drawing the shoe in between the 
step edge and the skirt panel is reduced. 
A further development of this nature is known from the U.S. Pat. No. 
4,413,719, granted Nov. 8, 1983 in which, inter alia, plastic components 
are set in a guiding fashion on the lateral tread sides which slidingly 
bear against the skirt panel. The plastic components possess a low 
coefficient or friction and fully take up the play between the step and 
the skirt panels, thus greatly reducing the danger of flimsy footwear 
being drawn in. 
However, both inventions have the disadvantage that the raised side 
portions of the steps or treads require more lateral space when running 
through the upper and lower comb plates and the danger of jamming is 
substantially increased when running into a comb plate when a wedged 
plastic component loosens during the course of time or is missing from the 
step tread for any reason. 
SUMMARY OF THE INVENTION 
Therefore, with the foregoing in mind, it is a primary object of the 
present invention to provide a new and improved construction of a support 
member or step member for a transport means which does not exhibit the 
aforementioned drawbacks and shortcomings of the prior art constructions. 
Another and more specific object of the present invention aims at providing 
a new and improved construction of an escalator step or step member of the 
previously mentioned type in which the step or step member reduces the 
danger of jamming between the steps and the skirt panels and requires no 
additional space when running through comb plates and with which no 
additional danger of jamming can arise when running through a comb plate. 
Yet a further significant object of the present invention aims at providing 
a new and improved construction of an escalator step or step member of the 
character described which is relatively simple in construction and design, 
extremely economical to manufacture, highly reliable in operation, not 
readily subject to breakdown or malfunction and requires a minimum of 
maintenance and servicing. 
Now to implement these and still further objects of the invention, which 
will become more readily apparent as the description proceeds, the 
construction of the present invention is manifested by the features that 
the projecting tread edge member is movably located and is held in a 
protruding or projecting safety position throughout a danger zone against 
a spring force by a cam or crank arm mounted on a pivot pin of a 
transporting medium or traction means and by an actuation means mounted on 
a lateral or side plate or wall of a step body and is pressably 
retractable outside the limits of the danger zone by the spring force into 
a position lying flush to the tread or step surface of the step or step 
member. 
In other words, the step member of the present invention is manifested by 
the features that each projecting tread edge member of the respective 
tread edge members is movably mounted. The step member comprises a spring 
means capable of exerting a force. The step member is subject to passage 
through a danger zone and defines a projecting safety position for the 
tread edge member. The continuous transport or traction means has at least 
one pivot pin. Respective cam means are mounted on each at least one pivot 
pin. A respective actuation means is mounted on each at least one side 
wall. The tread surface defines a flush position for the respective tread 
edge members. The respective cam means and the respective actuation means 
hold each projecting tread edge member in the projecting safety position 
counter to the force within the danger zone. Each projecting edge member 
is depressable into the flush position beyond the danger zone. 
Expressed differently, the step member is manifested by the features that 
spring means are arranged between the step body and the tread edge members 
for biasing the tread edge members into the retracted position. A chain 
wheel axle is journaled in the step body and is fixedly connected to a 
traction means of the transport means. The step member is provided with 
actuation means responsive to angular displacement of the chain wheel axle 
relative to the step body for selectively placing the tread edge members 
in the extended position during a predetermined portion of a path of 
travel of the transport means. 
The transport means of the present invention is manifested by the features 
that entrainment means are attached to each of the chain wheel axles and 
fixed against rotation relative thereto. The transport means comprises 
step members each comprising a step body having a tread surface and two 
lateral walls and pivotably journaled on an associated chain wheel axle of 
the chain wheel axles. The transport means comprises means for supporting 
and guiding the step members in the predetermined path of travel. Each 
step member is provided with a tread edge member arranged at least at one 
of the two lateral walls of the step member for performing extension and 
retraction motions relative to the step member such that each tread edge 
member projects above a tread surface of the step member in an extended 
position thereof and such that each tread edge member is substantially 
flush with the tread surface in a retracted position thereof. Each step 
member comprises spring means arranged between the step member and the 
tread edge members for biasing the tread edge members into the retracted 
position. Each step member comprises actuation means for engaging the 
entrainment means of the associated chain wheel axle for selectively 
placing the tread edge members in the extended position during a 
predetermined portion of the predetermined path of travel of the transport 
means in response to an angular displacement of the chain wheel axle 
relative to the step member. 
The method of the present invention is manifested by the features that it 
comprises the steps of exploiting an angular displacement of at least one 
member, such as a link member of the discrete link members to actuate the 
tread edge member. 
The advantages achieved by the invention consist substantially in that at 
least one movably located tread edge member substantially corresponding to 
a rib on the step body is raised and then retracted again on each step in 
the region of the lateral danger zones before running through the comb 
plate, i.e. during the transition from the lower or from the upper 
precursive level or substantially horizontal path or landing region to the 
inclined path or stair region and along the inclined path between the step 
body and the skirt panel. By raising these lateral ribs or tread edge 
members, a shoe or other object already gliding along the skirt panel in 
the region of the horizontal path will be forced upwards and the 
frictional force on the skirt panel simultaneously reduced. It is, 
however, more likely that the passenger will step away from the danger as 
soon as the raising of the foot by the lateral tread edge member is 
perceived. An already raised lateral tread edge member makes it difficult 
for the passenger to press the foot or the shoe against the skirt panel 
during travel. The tread edge member translatably connected with the step 
body cannot be improperly removed from the step body without damage. A 
further great advantage also consists in that an escalator step run having 
the inventive steps or step members can be incorporated into an existing 
escalator without any significant alterations having to be undertaken on 
the escalator.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Describing now the drawings, it is to be understood that to simplify the 
showing thereof only enough of the structure of the escalator step or step 
member has been illustrated therein as is needed to enable one skilled in 
the art to readily understand the underlying principles and concepts of 
this invention. Turning now specifically to FIGS. 1 and 2 of the drawings, 
the step member illustrated therein by way of example and not limitation 
will be seen to comprise a step body for an escalator labeled with the 
reference numeral 1. A drag wheel or roller 2 is rotatably positioned at a 
lateral or side plate or wall 1.1 of the step body 1. A journal 3 for 
pivotably mounting a rocker arm 4 is mounted on the same lateral or side 
plate or wall 1.1. One end of the rocker arm 4 possesses an open-ended 
guide slot 4.1 and the other end possesses a closed guide slot 4.2. An 
entrainment pin or crank pin 5.1 mounted on a cam or crank arm 5 engages 
the open-ended guide slot 4.1. The cam or crank arm 5 is fixedly connected 
with a pivot pin 7 of a traction member 8 either directly or through a 
chain wheel axle or stepped axle 6. The traction member 8 may, for 
instance, comprise a chain structure having discrete link members as 
generally indicated in FIG. 2. The pivot pin 7 may, for instance, be 
formed integrally with the chain wheel axle or stepped axle 6. On the 
pivot pin 7 of the traction member 8, chain rollers or wheels 9 are 
rotatably journaled or mounted for supporting the step body 1 on guide 
rails 10. At each pivot pin 7, one link of the traction member 8 is 
rotatably journaled while another is fixed, causing the stepped axle or 
chain wheel axle 6 to follow angular displacements of the fixed link in 
operation. An entrainment pin 11.1 mounted at a projecting tread edge 
member 11 of the step body 1 engages the closed guide slot 4.2 of the 
rocker arm 4. The projecting tread edge member 11 is depressed or forced 
downwards by the force of a spring 12 and, outside the limits of a danger 
zone, is thereby held in a position flush with a step surface or tread 
1.2. The spring 12 is supported on a support or bracket 1.3 mounted on the 
step body 1 and acts on a support or bracket 11.2 mounted on the 
projecting tread edge member 11. The projecting tread edge member 11 is 
guided in a parallel guide means 1.4 mounted substantially perpendicular 
to the step or tread surface 1.2 on the step body 1. 
In FIG. 3, a further embodiment of a step body for an escalator is labeled 
with the reference number 21. A step roller or drag wheel 22 is rotatably 
journaled or mounted on a lateral or side plate or wall 21.1 of the step 
body 21. Horizontal guideways 21.5 and vertical guideways 21.4 are also 
provided on the side wall 21.1. In the horizontal guideways 21.5, a 
sliding plate or cam plate 24 is translatably guided and in the vertical 
guideways 21.4, a projecting tread edge member 23 is translatably guided. 
The sliding plate or cam plate 24 possesses an open-ended guide slot 24.1 
and two closed guide slots or cam slots 24.2. An entrainment pin or crank 
pin 25.1 mounted on a cam or crank arm 25 engages the open-ended guide 
slot 24.1. The cam or crank arm 25 is fixedly connected with a pivot or 
hinge pin 26 of a traction member 28 either directly or through a not 
particularly illustrated step axle similar to the step axle 6 of FIG. 1. 
Two entrainment pins 23.1 mounted on the projecting tread edge member 23 
engage the closed guide slots or cam slots 24.2 of the sliding plate 24. 
The projecting tread edge member 23 is depressed or forced downwards by 
the force of a spring 29 and, beyond a danger zone, is held in a position 
flush with a step surface or tread surface 21.2 of the step body 21. The 
spring 29 is supported on a support or bracket 21.3 mounted on the step 
body 21 and acts upon a support or bracket 23.2 provided on the projecting 
tread edge member 23. A chain roller or wheel 27 running on a guide rail 
30 is rotatably journaled or mounted on a pivot pin 26 of the traction 
member 28. 
In FIG. 4, a further embodiment of a step body for an escalator is labeled 
with the reference number 31 which possesses a side wall or plate 31.1, a 
step surface or tread surface 31.2 and a swivel or pivot pin 31.3. A 
projecting tread edge member 38 is tiltingly or pivotably mounted or 
journaled on the swivel or pivot pin 31.3. By the force of a torsion 
spring 39 mounted on the projecting tread edge member 38, the projecting 
tread edge member 38 is, beyond a danger zone, held in a position flush 
with the step surface or tread surface 31.2. On the lateral or side plate 
or wall 31.1, a journal pin 33 is provided on which a rocker arm 34 is 
rotatably journaled or mounted. One end of the rocker arm 34 possesses an 
open-ended guide slot 34.1 and the other end of the rocker arm 34 
possesses a closed guide slot 34.2. An entrainment pin or crank pin 35.1 
mounted on a cam or crank arm 35 engages the open-ended guide slot 34.1. 
Again, the cam or crank arm 35 is fixedly connected with a pivot pin 36 of 
a traction member 40 either directly or through a not particularly 
illustrated step axle similar to the step axle 6 of FIG. 1. On the pivot 
pin 36, a chain roller or wheel 37 is rotatably journaled or mounted which 
supports the step body 31 on guide rails 41, 42 and 43 together with a 
step roller or drag wheel 32 also rotatably journaled or mounted on the 
step body 31. An entrainment pin 38.1 mounted on the projecting tread edge 
member 38 engages the closed guide slot 34.2 of the rocker arm 34. 
In FIG. 5, a forward run of an escalator step run 50 is labeled with the 
reference numeral 51 and a return run is labeled with the reference 
numeral 52. The forward run 51 extends between a lower comb plate 53 and 
an upper comb plate 54 and comprises a lower precursive level or 
substantially horizontal landing run 55, a lower transition curve 56, an 
inclined run 57, an upper transition curve 58 and an upper precursive 
level or substantially horizontal landing run 59. The endless escalator 
step run 50 turns at a lower reversing location 60 and at an upper 
reversing location 61. In the forward run 51 of the escalator step run 50, 
the steps 1, 21 and 31 move with a substantially constantly horizontal 
step surface or tread surface, whether ascending or descending the 
inclined run 57 or traveling through the landing runs 55 and 59. 
The pivot pins 7, 26 and 36 of the traction members 8, 28 and 40 are 
fixedly connected with associated members, here links of the respective 
traction members 8, 28 and 40. In the same manner, the cams or crank arms 
5, 25 and 35 are fixedly connected to the respective pivot pins 7, 26 and 
36 either directly or through the stepped or chain wheel axle 6. The angle 
of attack of the cams or crank arms 5, 25 and 35 relative to the 
longitudinal axis of the traction members 8, 28 and 40 is thus always the 
same. The relative movement of the step body 1, 21 or 31 relative to the 
longitudinal axis of the traction member 8, 28 or 40 which serves to 
maintain the step surface or tread or tread surface 1.2, 21.2 or 31.2 of 
the step substantially constantly horizontal during the forward run of the 
escalator step run also causes a relative angular displacement between the 
step body 1, 21 or 31 and the cam or crank arm 5, 25 or 35. This 
displacement takes place in the region of the transition curves 56 and 58 
between the inclined step run and the lower and upper horizontal step runs 
55 and 59. The relative motion starts in the region of a horizontal run 55 
or 59 and reaches a maximum value in the region of the inclined run 57. 
The entrainment pin or crank pin 5.1 or 35.5 mounted on the cam or crank 
arm 5 or 35 glides, according to FIGS. 1 and 4, into the open-ended guide 
slot 4.1 or 34.1 of the rocker arm 5 or 34 mounted on the step body 1 or 
31. Here, the rocker arm 5 or 34 rotates around the pivot or journal pin 3 
or 33 and tilts downwards on one side and upwards on the other side and 
forcibly moves or actuates the projecting tread edge member 11 or 38 
through the entrainment pin 11.1 or 38.1 upwards or downwards relative to 
the step surface or tread or tread surface 1.2 or 31.2. Additionally, the 
force of the spring 12 or 39 acts constantly on the projecting tread edge 
member 11 or 38. By means of the spring 12 or 39, the projecting tread 
edge member 11 or 38 is constantly pulled toward the step surface or tread 
1.2 or 31.2 of the step body 1 or 31 and the projecting tread edge member 
11 or 38 is held in a position lying flush with the step surface or tread 
of the step body in the region of the horizontal run 55 or 59 of the 
forward run 51 as well as over the whole return run 52 of escalator step 
run 50. For example, with an escalator travelling upwards, each step 
appears out of the lower comb plate 53 with retracted tread edge members 
11 or 38 lying flush with the step surfaces or treads and thus rolls over 
or glides through the lower horizontal run 55. As soon as the step surface 
or tread of the step rises from the region of the horizontal run 55 
through the subsequent lower transition curve 56 into the region of the 
inclined run 57, the lateral tread edge members also rise gradually until 
they progress into the region of the inclined run 57 in a maximum 
projecting or extending manner at the end of the lower transition curve 
56. In this position, the steps move along the region of the inclined run 
57 and into the upper transition curve 58. The height of the extended or 
projecting tread edge members then decreases again until the steps run 
through the upper comb plate 54 after traveling through the upper region 
of the horizontal run 59 with the tread edge members flush with the step 
surface. While the projecting tread edge members are held in this flush 
position over the whole region of the return run by the force of the 
spring 12 or 39, the entrainment pin or crank pin 5.1 or 35.1 of the cam 
or crank arm 5 or 35 disengages from the open-ended guide slot 4.1 or 34.1 
of the rocker arm 4 or 34 in the upper reversing position 61 in order to 
engage again in this open-ended guide slot 4.1 or 34.1 at the lower 
reversing position 60 at the end of the return run 52 before the step 
reaches the lower comb plate 53 again and starts a further revolution. In 
the same manner, the translation of the projecting tread edge members 11 
or 38 occurs in reverse order in a downwardly travelling escalator. 
Instead of the rocker arm 4 or 34 responsible for the movement of the 
projecting tread edge members described above and illustrated in FIGS. 1 
and 4, the slide plate or cam plate 24 illustrated in FIG. 3 can be 
employed. By the relative displacement or translation of the cam or crank 
arm 25 relative to the step body 21, the sliding plate 24 is reciprocated 
for actuating the projecting tread edge member 23 upwards and downwards by 
means of the guide slots or cam slots 24.2 and the entrainment pins 23.1. 
Instead of a translation of the projecting tread edge member parallel to 
the step surface or tread of the step, as is illustrated in FIGS. 1 and 3, 
an ascendantly prone translation of the projecting tread edge member can 
be provided as is illustrated in FIG. 4, or a not particularly illustrated 
descendantly prone translation of the projecting tread edge member can be 
provided. 
It is furthermore possible to lengthen the projecting tread edge members 
illustrated in FIGS. 1, 3 and 4 and to extend the projecting tread edge 
members over the whole depth of the step. 
It will be appreciated that the teachings of the invention can equally well 
be applied to horizontal transport means analogous or related to 
escalators, commonly known as moving sidewalks or walkways. While there is 
less danger of jamming in moving sidewalks or walkways, the means or 
facilities of the invention can advantageously prevent lateral scuffing. 
In such an application, there is no transition from a horizontal run to an 
inclined run and it is therefore necessary to exploit a different angular 
displacement between the step member and the traction means, namely that 
arising as the moving sidewalk or walkway leaves the turning region and 
enters its straight run. Since this angular displacement is of the reverse 
sense, the actuation means for extending and retracting the tread edge 
members must be correspondingly modified. 
While there are shown and described present preferred embodiments of the 
invention, it is to be distinctly understood that the invention is not 
limited thereto, but may be otherwise variously embodied and practiced 
within the scope of the following claims.