TRACTION SHEAVE ELEVATOR
The present invention relates to a traction sheave ele-
vator.
In prior art, specifications DE-U-29704886 and EP-A2-
0631967 present elevators in which the elevator car and
the counterweight have been arranged to move along a
guide track in an elevator shaft. Both ends of the ele-
vator rope are attached to a fixed structure and the
elevator car and counterweight are carried by the rope.
The rope is passed over rope pulleys. The traction
sheave is driven by a traction, motor. Rope pulleys are
. mounted on the counterweight, on a fixed overhead
structure and on the elevator car. The basal structures
of the elevator car are provided with a pair of rope
pulleys and the rope is passed via this pair of pulleys
so that it goes once under the car and the elevator car
is thus supported by the rope.
Since the aim is- to place the elevator car in a centric
fashion in the car frame or an equivalent supporting
structure if possible and to place the car guides lean-
ing against the guide rail as close as possible to a
plane intersecting the centre line or centre of gravity
of the elevator car, it is difficult to achieve a cen-
tric supporting effect on the car or car frame of rope
suspension with ropes passing under the elevator car.
When the rope' runs via a single pair of rope pulleys
attached to the elevator car, the load is applied via
the rope pulley suspension to only one line passing un-
der the car. Furthermore, suspending the car on a sin-
gle pair of rope pulleys, especially in the case of
freight elevators used to transport heavy loads, leads
to a necessity to use thick ropes and rope, pulleys with
a large diameter.
The object of the present invention is; to eliminate the
drawbacks described above
A specific object of the present invention is to dis-
close a traction sheave elevator in which the load ap-
plied via rope suspension can be distributed over a
larger area in the elevator car structure than before.
Another object of the invention is to provide a possi-
bility to implement a rope-driven freight elevator
without machine room to replace conventional hydraulic •
freight elevators. A further object of the invention is
to disclose an arrangement that enables a lighter ele-
vator car structure to be achieved.
Accordingly the present invention provides:
1. Traction sheave elevator, comprising
- an elevator car (2), which has been arranged to move
along a guide track (A) in the elevator shaft (1);
- a counterweight (3), which has been arranged to move
along a guide track (B) in the elevator shaft (1);
- a rope (4), both ends of which are attached to a
fixed overhead structure (5) in the upper part of the
elevator shaft, the elevator car and the counter-
weight being carried by said rope;
- a number of rope pulleys (6 - 14), one of which is a
traction sheave while the others are diverting pul-
leys and via which the rope is passed and which rope
pulleys are connected to the counterweight (3J, to a
fixed overhead structure (5) in the upper part of the
elevator shaft (1) and to the elevator car (2), which
is provided with a first pair of car rope pulleys (6,
7) in which the car rope pulleys (6 and 7) are
mounted on the elevator car at a distance from each
other; and
- a traction motor (15) arranged to drive the traction
sheave (8),
characterised in that the traction sheave elevator com-
prises a second pair of car rope pulleys (9, 10) con-
nected to the elevator car, in which the car rope pul-
leys (9 and 10) are placed at a distance from each
other, and an auxiliary rope pulley (11) connected to
the fixed overhead structure (5); and that the rope (4)
is passed from a car rope pulley (7) of the first pair
of car rope pulleys (6, 7) via the auxiliary rope pul-
ley (11) mounted on the fixed overhead structure to a
car rope pulley • (10) of the second pair of car rope
pulleys (9, 10).
According to the invention, the traction sheave eleva-
tor comprises a second pair of car rope pulleys con-
nected to the elevator car, in which the car rope pul-
leys are placed at a distance from each other, and an
auxiliary rope pulley mounted on a fixed overhead
structure in the building. The rope is passed from a
car rope pulley in a first pair of car rope pulleys to
the auxiliary rope pulley mounted on a fixed overhead
structure and further to a car rope pulley in the sec-
ond pair of car rope pulleys.
The invention has the advantage that as the elevator
car is provided with at least four pulleys placed at a
distance from each other over which the rope passes
twice, going over the auxiliary rope pulley in between,
the load is distributed over a large area in the eleva-
tor car. The elevator car can be built using a lighter
and less rigid structure than • in earlier elevators.
Moreover, the invention discloses an elevator capable
of hoisting relatively heavy loads using a motor that
has a relatively low power rating and is therefore
small.
In an embodiment of the elevator, the second pair of
car rope pulleys is at a distance from the first pair
of car rope pulleys so that the rope portion passing
via the first pair of car rope pulleys is substantially
parallel to the rope portion passing via the second
pair of car rope pulleys. The car rope pulleys are dis-
posed in a rectangular configuration.
In an embodiment of the elevator, the first pair of car
rope pulleys and the second pair of car rope pulleys
are symmetrically disposed on either side of the centre
line of the elevator car, thus producing a balanced
structure.
In an embodiment of the elevator, the counterweight is
provided with a' first counterweight rope pulley and a
second counterweight rope pulley. A second auxiliary
rope pulley is mounted on a fixed overhead structure
directly above the counterweight. The rope is passed
from the first counterweight rope pulley .to the second
counterweight rope pulley via the second auxiliary rope
pulley.
In an embodiment of the elevator, the first pair of car
rope pulleys and the second pair of car rope pulleys
are disposed under the elevator car, the rope being
thus passed by a route below the elevator car.
In an embodiment of the elevator, the first pair of car
rope pulleys and the second pair of car rope pulleys
are disposed on top of the elevator car, in which .case
the rope is passed by a route above the elevator car.
In an embodiment of the elevator, the rope is passed
from a fixed overhead structure, to which its first end
is attached, to the first counterweight rope pulley.
From the first counterweight rope pulley, the rope is
passed to the second auxiliary rope pulley. From the
second auxiliary rope pulley, the rope is passed to the
second counterweight rope pulley. From the second coun-
terweight rope pulley, the rope is passed to the pulley
on the traction motor, i.e. to the traction sheave.
From the traction sheave, the rope is passed to the car
rope pulleys of the first pair of car rope pulleys.
From a pulley in the first pair of car rope pulleys,
the rope is passed to the first auxiliary rope pulley.
From the first auxiliary rope pulley; the rope is
passed to the car rope pulleys of the second pair of
car rope pulleys. From a car rope pulley in the second
pair of car rope pulleys, the rope is passed to a fixed
overhead structure,' to which the second end of the rope
is attached.
In an embodiment of the elevator, in respect of the
rope pulleys of the second pair of car rope pulleys,
the speed ratio between the elevator car and the coun-
terweight is 1:1.
In an embodiment of the elevator, the first end of the
rope, the second end of the rope, the first auxiliary
rope pulley, the second auxiliary rope pulley and/or
the traction motor are mounted on guide rails. The
guide rails are preferably planted on the bottom of the
elevator shaft to pass the vertical forces down to the
groundwork. Passing the vertical forces via the guide
rails down • to the groundwork provides an advantage as
it makes the elevator independent of the wall struc-
tures of the building, which is a great advantage espe-
cially in feeble-constructed buildings, such as indus-
trial sheds.
In the following, the invention will be described in
detail, by the aid of a few examples of its embodiments
by referring to the attached drawings, wherein
Fig. 1 presents a diagram representing a first embodi-
ment of the traction sheave elevator of the invention,
seen in perspective view obliquely from above,
Fig. 2 presents a diagram representing a second embodi-
ment of the traction sheave elevator of the invention,
seen in perspective view obliquely from above.
Fig. 1 shows a so-called traction sheave elevator,
which can be used as a low-speed freight elevator. The
elevator car 2 has been arranged to move along guide
rails A in the elevator shaft 1. Likewise, the counter-
weight 3 has been arranged to move along its own guide
rails B in the elevator shaft. Both the elevator car 2
and the counterweight are carried by the same rope 4.
For the sake of clarity, the figures show only one
rope, but of course the rope may comprise a rope bundle
or a number of adjacent ropes, as is customary in ele-
vator technology. Similarly, the figure shows simple
grooved rope pulleys, but it is clear that when several
adjacent ropes are used, the pulleys must have a corre-
sponding number of grooves or several pulleys are used
side by side. The diverting pulleys may have grooves of
semicircular cross-section and the traction sheave may
have undercut grooves to increase friction.
As shown in Fig. 1, both ends 16 and 17 of the rope 4
are anchored in a fixed overhead structure 5 in the
building. The rope 4 is passed over a number of rope
pulleys 6-14. The counterweight rope pulleys 12 and
13 are connected to the counterweight 3. The first aux-
iliary rope pulley 11 and the second auxiliary rope
pulley 14 are connected to the fixed overhead structure
5. Car rope pulleys 6, 7, 9 and 10 are connected to the
elevator car 2. The traction motor 15 has been arranged
to drive one of the rope pulleys 8. The fixed overhead
structure 5 to which the ends 16 and 17 of the rope 4
and the auxiliary rope pulleys 11 and 14 are attached
may be e.g. the ceiling of the elevator shaft or e.g.
guide rail A and/or B. In the embodiment illustrated by
Fig. 1, the ends 16 and 17 of the rope 4 and the auxil-
iary rope pulleys 11 and 14 are fixed to the guide
rails, which is an advantageous arrangement because it
makes the elevator independent of the wall structures
of the building and allows the use of feeble-
constructed walls. Large vertical forces can be trans-
mitted down to the groundwork while lateral forces are
transmitted via the guide rail fixtures to the walls of
the elevator shaft or to similar structures.
The traction motor 15 is a synchronous motor with per-
manent magnets, and the drive pulley 8 is integrated
with its rotor. The motor is mounted in the elevator
shaft 1 and attached to the upper part of a guide rail
A.
The elevator car 2 is provided with two pairs of car
rope pulleys, a first pair of car rope pulleys 6, 7, in
which the car rope pulleys 6 and 7 are placed at a dis-
tance from each other near the opposite lower edges of
the bottom of the elevator car, and a second pair of
car rope pulleys 9, 10, in which the car' rope pulleys 9
and 10 are correspondingly placed at a distance from
each.other near the opposite lower edges of the bottom
of the-elevator car. The first pair of car rope pulleys
6, 7 and the second pair of car rope pulleys 9, 10 are
substantially symmetrically disposed on either side of
the centre line of the elevator car 2, thus providing a
stable suspension with widely spaced supporting points,
distributing the load over a large area in the elevator
car.
The rope 4 is passed from a car rope pulley 7 of the
first pair of car rope pulleys 6, 7 via auxiliary rope
pulley 11 in the fixed overhead structure 5 to a car
rope pulley 10 of the second pair of car rope pulleys
9, 10 on the elevator car 2. The second pair of car
rope pulleys 9, 10 is at a distance from the first pair
of car rope pulleys 6, 7 so that the rope portion run-
ning via the first pair of car rope pulleys 6, 7 under
the elevator car 2 is substantially parallel with the
rope portion running via the second pair of car rope
pulleys 9, 10 under the elevator car 2. The running di-
rection of the rope 4 between the car rope pulleys. 6
and 7 in the first pair of car rope pulleys is opposite
to the running direction of the rope portion between
the car rope pulleys 9 and 10 in the second pair of car .
rope pulleys.
In the embodiment illustrated by Fig. 2, the only dif-
ference as compared with the embodiment in Fig. 1 is
that the first pair of car rope pulleys 6, 7 and the
second pair of car rope pulleys 9, 10 are disposed on
the top side of the elevator car 2. The rope 4 is
therefore passed twice by the top side of the elevator
car 2 and the elevator car 2 is .suspended from the
rope.
Referring further to Fig. 1, the counterweight 3 is
provided with a first counterweight rope pulley 12 and
a second counterweight rope pulley 13, which are con-
nected to the counterweight so that their planes of ro-
tation are substantially in the same vertical plane, in
other words, so that the axes of rotation of the pul-
leys 12 and 13 are parallel to each other. Connected to
a fixed overhead structure 5 at about the same plane
with the counterweight 3 is a second auxiliary rope
pulley 14. The rope 4 is passed from the first counter-
weight rope pulley 12 via the second auxiliary rope
pulley 14 to the second counterweight rope pulley 13.
The speed ratio between the elevator car 2 and the
counterweight 3 is thus 1:1.
In the embodiments in Fig. 1 and 2, the first end 16 of
the rope 4 is attached to a fixed overhead structure 5
in the upper part of the elevator shaft 1. From the
fixed overhead structure 5, the rope 4 is passed via
the first counterweight rope pulley 12 to the second
auxiliary rope pulley 14. Via the second auxiliary rope
pulley 14, the rope is passed to the second counter-
weight rope pulley 13 and via it further over the rope
pulley 8 of the traction motor 15 via the rope pulleys
of the first pair of car rope pulleys 6, 7 and over the
first auxiliary rope pulley 11 via the rope pulleys of
the second pair of car rope pulleys 9, 10 to the fixed
overhead structure 5, to which the second end 17 of the
rope 4 is attached.
In some elevators, when the elevator is being loaded
with heavy cargo or for other reasons, it may be neces-
sary to prevent rope movement between the rope loops
supporting the elevator car. Rope movement during load-
ing can be prevented by using a brake acting on the
rope or on a rope pulley mounted on the elevator car or
on an auxiliary rope pulley 11. An advantageous stabi-
lisation of the elevator car, effective even during op-
eration, is achieved via appropriate placement of the
drive machine. By placing the elevator drive machine
together with the traction sheave in the position re-
served for auxiliary rope pulley 11 in the embodiments
in Fig. 1 and 2, an advantageous configuration in re-
spect of stability of the elevator car is achieved. In
this case, the traction sheave, in which the friction
between the rope and the rope grooves is often higher
than in the other pulleys and in which the rotary mo-
tion driving or braking the elevator rope is dependent
on the operation of the drive machine, functions as an
element holding'back the rope between the rope portions
supporting the elevator car, i.e. between the rope por-
tion going from the traction sheave towards the coun-
terweight and the rope portion going from the traction
sheave in the opposite direction relative to the length
of the rope.
The invention is not restricted to the examples of its
embodiments described above, but many variations are
possible within the scope of the inventive idea defined
by the claims.
CLAIMS :
1. Traction sheave elevator, comprising
an elevator car (2), which has been arranged to move along a first guide track (A) in the
elevator shaft (1);
a counterweight (3), which has been arranged to move along a second guide track (B) in the
elevator shaft (1);
a rope (4), both ends of which are attached to a fixed overhead structure (5) in the upper part
of the elevator shaft, the elevator car and the counterweight being carried by *said rope;
a number of rope pulleys (6-14), one of which is a traction sheave while the others axe
diverting pulleys and through which the rope is passed and which rope pulleys are connected
to the counterweight (3), to a fixed overheetd structure (5) in the upper part of the elevator
shaft (1) and to the elevator car (2), which is provided with a first pair of car rope pulleys (6,
7), the pulleys of the first pair of car rope pulleys (6 and 7) being connected to the elevator
car at a distance from each other; and
a traction motor (15) arranged to drive the traction sheave (8),
characterised in that the traction sheave elevator comprises
- a second pair of car rope pulleys (9,10) connected to the elevator car, in which the car rope
pulleys (9 and 10) are placed at a distance from each other, and
- an auxiliary rope pulley (11) connected to the fixed overhead structure (5); and that the rope
(4) is passed from the traction sheave (8) via a car rope pulley (6) of the first pair of car rope
pulleys (6, 7) and further from the other car rope pulley (7) of the first pair of car rope pulleys
(6,7) via the auxiliary rope pulley (11) mounted on the fixed overhead structure to a car rope
pulley (10) of the second pair of car rope pulleys (9,10).
2. Elevator as claimed in claim 1, wherein the second pair of car rope pulleys (9, 10)
is at a distance from the first pair of car rope pulleys (6, 7) so that the rope portion passing
via the first pair of car rope pulleys is substantially parallel to the rope portion passing via
the second pair of car rope pulleys.
3. Elevator as claimed in claim 2, wherein the first pair of cat rope pulleys (6, 7)
and the second pair of car rope pulleys (9, 1 0) are symmetrically disposed on either side of the
center line of the elevator car.
4. Elevator as claimed in claim 1, wherein it comprises a first counterweight rope
pulley (12) and a second counterweight rope pulley (13), both connected to the counterweight
(3); that a second auxiliary rope pulley (14) is mounted on the fixed overhead structure (5)
directly above the counterweight; and that the rope (4) is passed from the first counterweight
rope pulley (12) to the second counterweight rope pulley (13) via the second auxiliary rope
5. Elevator as claimed in claim 1, wherein the first pair of car rope pulleys (6, 7)
and the second pair of car rope pulleys (9,10) are disposed under the elevator car (2), the rope
(4.) being thus passed by a route below the elevator car.
6. Elevator as claimed in claim 1, wherein the first pair of car rope pulleys (6, 7)
and the second pair or car rope pulleys (9,10) are disposed on top of the elevator car, in
which case the rope (4) is passed along the top side of t^ie elevator car (2).
7. Elevator as claimed in claim 1, wherein the rope (4) is passed from the fixed
overhead strucrure (5) via the first counterweight rope pulley (12) to the second auxiliary rope
pulley (14) and further to the second counteiweight rope pulley (13) and from there further to
the traction sheave (8) of the traction motor (6), from which it is further passed vi£ the car
rope pulleys of the first pair of car rope pulleys (6, 7) to the first auxiliary rope pulley (11)
and from there further via the car rope pulleys of the second pair of car rope pulleys (9,10) to
the fixed overhead structure (5).
8. Elevator as claimed in claim 1, wherein the speed ratio between the elevator car (2)
and the counterweight (3) is 1:1.
9. Elevator as claimed in claim 1, wherein the first end (16) of the rope (4), the
second end (17) of the rope, the first auxiliziry rope pulley (11), the second auxiliary rope
pulley (14) and/or the traction motor (15) are mounted on guide rails (A, B).
10. Elevator as claimed in claim 1, wherein the guide rails (A, B) are planted on the
bottom of the elevator shaft (1) to transmit the vertical forces t;o the groundwork.
10 Elevator as claimed in any of claims 1-9, wherein the guide rails (A, B) are
planted on the bottom of the elevator shaft (1) to pass the vertical forces down to the
groundwork.

The invention relates to a traction sheave elevator. The elevator car (2)
moves along guide track (A) in an elevator shaft (1). The counterweight (3)
moves along guide track (B) in the elevator shaft (1). Both ends of rope (4)
are attached to a fixed overhead structure (5). The elevator car and the
counterweight are supported by the rope. The rope (4) is passed via a
number of rope pulleys (6 - 14), one of which is the traction sheave while the
others are diverting pulleys. Rope pulleys are connected to the counterweight
(3), to the fixed overhead structure (5) in the upper part of the elevator shaft
and to the elevator car (2). The elevator car is provided with a first pair of car
rope pulleys (6, 7). The traction motor (15) drives one of the rope pulleys,
which is the traction sheave. Connected to the elevator car is a second pair of
car rope pulleys (9, 10). An auxiliary rope pulley (11) is connected to the fixed
overhead structure (5). The rope (4) is passed from a car rope pulley (7) of
the first pair of car rope pulleys (6, 7) via the auxiliary rope pulley (11)
mounted on the fixed overhead structure to a car rope pulleys (10) of the
second pair of car rope pulleys (9, 10).