Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a winding
gear of an elevator or lift adapted to lift a load, gear
which includes a casing ha~ing a pair of shaft bearings
which carries an output shaft having an end portion that
extends out of the casing, a cable pulley being mounted
on the shaft extending end portion for supporting the
load, which load exerts on the cable pulley and i~ turn
on the shaft a radial ~orce acting in a predetermined
direction, there being further provided a third bearing
in which the shaft extending end portion is journalled,
the cable pulley being located between the casing and
this third pulley.
Such winding gears comprising three bearings
for the output shaft are currently used when the load
borne by the cable pulley is large enough that arranging
the cable pulley in overhanging fashion would require
unduly increasing the ~imensions of the output shaft and,
as well, of the bearings and other components of the
winding gear associated therewith. This is particularly
the case, for instance, in elevators capable of trans-
porting a large number of people and for certain goods-
lifts. The positioning, at the extreme end of the out-
put shaft, of this supplementary bearing separately
secured to a base plate supporting the winch casing or
to a base plate adjacent to it, requires however an
important alignment work. With such a hyperstatic
system, if the alignment of the bearings is not perfect,
there is a chance that one of the bearings and/or the
output shaft wear out rapldly or that the output shaft
break due to the stresses resulting from the mounting of
this third bearing.
German application No. ST 14~5, granted 2.7 53,
shows an elevator winch gear in which, to avoid the use
of a third bearing, the winch casing is provided with a
stationary cylindrical sheath which extends past the
;2~
casing and within which the output shaft of the winch
is rotatably housed. The cable pulley is rotatably
mounted on the end of the cylindrical sheath and its hub
has a driving nose keyed t~ the end of the output sha~t
which projects out of the sheath. Such a solution has
the advantage to free the output shaft of radial stresses
resulting from the load which is thus supported by the
bearing constituted by the stationary cylindrical sheath.
In this ~anner, the risks that the driving shaft break
are reduced. However, the necessity of providing a
stationary sheath acting as an inner bearing for the
output shaft leads to a substantial increase in the
dimenslons of the winch casing and such a solution is
relatively complicated and costly, namely because it
requires a particular shaping of the hub of the cable
pulley.
The purpose of the present invention is to
provide a lift or elevator winch gear which, while being
of simple construction, makes it possible to facilitate
the assembling of the gear and to avoid any risk that the
output shaft break.
In accordance with the present invention, this
object is achieved by the provision,with a winding gear
of the aforesaid type,of means supporting and resiliently
biasing the third bearing in a direction, radially of the
shaft extending end portion, which is in opposition to
the predetermined direction, these means being further
adjustable so as to be able to exert on the third
bearing a force which is at least equal to the force
exerted by the load on the shaft extending end portion.
The major advantage of the present invention
resides namely in that it makes it possible to apply a
prestress on the output shaft in a radial direction
which is opposite that of the force exerted by the load.
In this manner, when the cable pulley is subjected to a
'
load, the strain on the bearings of the w.inch casing is
relieved and the working rate of the output shaft is
appreciably reduced and, consaquently, its fatigue~ As
a result, the invention permits not only to avoid
rupturing the shaft but it also allows, up to a certain
``i;~3,
. 2a -
26~
extent, to reduce its dimensions and that of the
elements, such as the bearings, which are directly
associtated with it. It thus becomes possible to
design a li~hter and less costly lift or elevator winding
gear, for a predetermined load. Likewise and within
permissible limits, the admissible load may ~e increased
for a predetermined type of winding gear.
In accordance with a preferred embodiment of
the invention, the aforesaid bearing means comprise:
support means; a bias adjusting device mounted on the
support means, and at least one spring havin~ one end
applied against the third bearing and the other end
applied against the adjusting device whereby the bias
applied by the spring may be adjusted by the adjusting
means.
The aforesaid support means may preferably
comprise: a chassis on which the casing is fixed; an
upright member secured to the chassis; a bracket on
which the bias adjusting device is mounted and means
selectively positioning the bracket by rotation thereof
about the axis of the shaft and securing the bracket
to the upright member in the selected position.
A preferred embodiment of the invention is
described hereinafter, by way of example, with reference
to the appended drawing wherein:
Fig. 1 is a schematic view partly in elevation
and partly in cross-section of an elevator or lift
winding gear made according to the invention, and
Fig. 2 is a schematic side elevation view of
the winding gear of Figure 1.
Referring to the drawing, there is shown a
base plate or winch chassis 1 intended to be located in
the lift winding gear room and on which is secured a
winch casing 2 containing all or a portion of the non-
illustrated li~t driving mechanism such as an endless-
-- 3 --
screw reducer, a braking system or any other con-
ventional parbs associated wi-th the non~illustrated
driving motor.
An output shaft 3 is carried by two bearings,
not shown, provided within the winch casing 2 and on
which is mounted a cable or yripping pulley 4 to which
are respectively suspended, through cables 5, the lift
or elevator cab and its counterweight, not shown, of the
elevator or lift.
An auxiliary or third bearing 7 is located
outwardly of the winch casing 2, at the extreme end 3.1
of the output shaft 3. The end of this third bearing 7
has a rectilinear face 7.1 (Figure 2), against which
supporting and resiliently biasing means are applied.
More specifically, the latter means comprises a coil
spring ~ of which one end bears agai~st the face 7.1
while the other end bears against the bottom of a cup-
shaped guide 9 moun-ted at the end of a screw 10 which is
part of a device for adjusting the tension of the said
screw 10 and a nut assembly carried by a ben-t part 12.1
of a bracket 12 capable of being oriented by rotation
about the output shaft 3. The aforesaid supporting and
resiliently biasing means further includes an upright
member 13 solid with the base plate or winch chassis 1
and to which the bracket 12, once properly oriented,
may be secured by means of three securing screws 14
(Figure 2). The angle of rotation allowed the bracket
12 with respect to the upright member 13 is sufficient
for, during mounting and in relation to the resultant
of the cables 5 and 6, -the elastic force R of the
spring 8 to bias the third bearing 7 and consequently
the output shaft 3 radially in a direction which is
opposite that of the force G acting on the output shaft
3 and resulting from the cable puIley 4 supporting the
load.
,~ _
: '.
The dimensions and the characteristics of the
coil spring 8 are selected in relation to -the force G,
in such a manner that a prestress oE the output shaft 3
may be obtained by a simple adjustment of the tension in
the spring 8 by means of the screw 10, prestress which
is compensated once the load is supported by the cable
pulley 4. Thus, any danger that the output shaft 3
break by fatigue, is practically eliminated and alignment
of the bearin~s is no longer necessary during assembly.
It goes without saying that, in the above
embodiment, only such elements as are essential to the
invention have been described in support of a purely
schematic illus-tration. Details of construction, such as
those relating to guiding of the spring and/or attachment
of elements which are within the skill o~ the man in
the art have not been illustrated. Similarly, in order
to produce the elastic force, it is possible to use
several simultaneously acting springs for one or several
elements made of a material capable of achieving similar
results. Finally, it is also whithin the scope of the
present invention to provide, for instance through
hydrauli.c means, that adjustment of the elastic force
applied to the third bearing be made in relation -to
variations in the load supported by the cable pulley.
