Note: Descriptions are shown in the official language in which they were submitted.
CA 02574392 2007-01-18
ELEVATOR GEARLESS TRACTION MACHINE CONSTRIICTION
Field of Invention
This invention relates to elevator drives, and in particular to a univelsal
machine
frame construction.
Background of Invention
Gearless traction machines are generally driving a wide range of electric
traction
elevators. Fig. I and Fig. 2 show a typical gearless traction machine
constniction existing in
the art. A traction sheave 10 is driving a pliu ality of ropes 12 having one
eid connected to an
elevator car aiid the other cnd connected to a counterweight. '1'he shcave 10
is rigidly
mounted on a shafl 14 whicli rotates on bearings 16, 18 mounted in pedestF Is
20, 22. An
eJectric motor 24 is generally attached to one oftho pedestals 22 and drives
the shaft 14 and
the sheave 10. In order for the machine to be rigid, the pedestals 18, 20 arf
generally
mounted on a massive steel structure 26 called a bedplate. Such prior art
ccinstruction is
displayed in Japanese patent JY2003201082, among others.
The problem inherent to this design is that the ropes 12 often interf ,-re
with the
bedplate 26 when the diameter of the sheave 10 clianges. 'C'his interferencts
is shown in Fig. 2
as X when the sheave diameter is increased to the value D. The sheave
dit,meter can vary
because ropes can be ofdiflereiit diameters and the sheave diameter is
generally a multiple of
the rope diameter (approximately 40 times). Therefore, the construction
d;scribed above is
not flexible because certain sheave diameters are prohibited or requixe a
specific steel
structure in order to be implemented. The bedplatc steel structure 26 is
generally a massive
welded steel assembly, mal:ing this change expensive and undesirable. Aaiother
problein is
that the dimensioning of the lower stecl structure also needs to be chaiigec
to accommodate
sheaves of various widths. The width of lhe sheave can vary, depending c-n the
number of
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ropes 12, which can number between 2 and 10 or more, based upon the tot-, 1
elevator ioad
being moved.
An alternative construction is described in U.S. Patent No. 4,679,661. This
reference
discloses a sheave that is "overhung", meaning that it is not supported at
ojte end. This
construction allows any sheave diameter to be used because the ropes do n.3t
interfere with
any pait of the supporting st.ructure. Ho rever, this arrangement produces a
large bending
moment applied on the sheave. Therefore, the niain structurc needs to be -ery
massive in
order to limit deflectioiis and stresscs, leading to increased cost.
In other prior art en.ibodiments the motor has a so-called "extental rotor"
(EP1411620A1, JP2002274770, DE4233759AI) but the pedestals supporting the
inachine are
also mounted on a heavy steel structure that eventually inteiferes with the
ropes. In addition,
a major disadvantage of such external rotor construction is that the sheave
diameter is
dependent of the motor diaineter, thus reducing the flexibility of the
machine.
Summary of Invention
The present inve,iition is an improved and versatile elevator machi ie
construction
allowing maximum flexibility for sheave dianietcrs and sheave width while
reducing the
overall cost of the machine.
The elevator machinc mount construction comprises a first fra.rne member
liaving a
first hcaring mounting aperture therein and a first plurality of holes and a
second frame
member having a second bearing mounting aperture thercin and a second
plurality of holes.
The first plurality of holes and the second plurality of holes are oriented
r,uch that the holes in
the first frame member and the holes in the second frame member are
sulistantially aligned in
pairs. A pluaality of connecting rods is provided, each having a first end
passing through one
of the plurality of holes in the first frame member, and a second end pas: ing
through the
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substantially aligned hole in the second fraine member. Fasteners are located
on the first end
and the second end of each t+f the plurality of connecting rods.
Each of the plurality of connecting rods has a first shoulder and a s-:cond
shoulder
positioned adjacent to the first and second frame members respectively, to
separate the first
and second fracne niembers. The ends of each of the plurality of connectir g
rods are threaded
with a nut threaded onlo each end.
A spacer may be positioned about each of the plurality of the conn.:cting rods
adjacent
to the outer face of the second frame member and a motor mounted on the
connecting rods
and separated from the second frame member by the spacer. A shaft, having a
sheave, passes
tltrough bearings mounted in the apertures in the first and second franie
members, with the
sheave positioned between the frame members_ A su.spcnsion for an elev<<tor
car is mounted
on the sheave for raising and lowering the elevator car.
The plurality of connectuig rods may be repositioned into altematis holes in
the first
and second frame members to accominodate sheaves of various diameter: while
preventing
interference between the elevator car suspension and the connecting rods.
Additionally, the
length of the conneccilig rods may be varied to accommodate sheavcs of -arious
widths.
Brief Description of Drawings
The foregoing and other aspects of the invention will become mo;-e apparent
from the
following description of examples embodying the best mode of the invention
taken in
conjunction with the accompanying drawings which illustrate, by way of example
only and
not interiding to be limiting, the principles of the invention. In the drawi
zgs:
Fig. I schematically shows a typical arrangement of gearless ele~ ator machine
constniction existing in the art.
Fig. 2 is a section vicw of a typical arrangement taken at 2-2 in Fig. 1.
Fig. 3.is a perspec.tive view of a machine built according to the p-escnt
invention.
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Fig. 4 is a semi sectional view of the machine illustrated in Fig. 3,
shotiving detail.
Fig. 5sliows an end vicw of a machine driving an elevator via a fla: belt and
a
relatively smaller sheave.
Fig. 6 shows a perspective view of tlie embodiment of Fig. 5.
Fig. 7 shows an end view of a machine driving aii elevator via a flat belt and
a
relatively larger sheave.
Fig. 8 shows a perspective view of the embodiment of Fig. 7.
Fig. 9 is an enlarged illustration showing in detail the connecting rod
assembly.
Detailed Description of Illustrative Embodiments
Referring to Fig. 3 and Fig. 4, iwo frame members 100, 102, prefe,ably
identical, are
connected by a plurality of connecting rods 104. Frtuue members 100, 102 are
fabricated
from metal such as steel plate of such thickness to provide adequate suppc-rt
for the machine,
as will be evidcnt to one skilled in the art. A plurality of holes 103 are dr
lied, or otherwise
machined by means well known i-n the art, in frame members 100, 102 su:h that
the holes in
frame member 100 substturtially align with the holes in frame member 102.
Provision is also
made in frame members 100, 102 for mounting bearings 120, 121 respecl ively to
support a
sha.tl: 118. Frame members 100, 102 are then mounted to a plate 142 by tncans
known in the
art. In the preferred cmbodiment, the franie members 100, 102 are mounted to
the plate by
bolts 146.
In the preferred embodiine.nt shown in Fig. 3 and Fig. 4, four metal
connecting rods
104 are used. '1'he same connecting rods also support the stator .112 of the
motor 1 10. The
motor I 10 has a so-called "frarnelcss" construction, meaning that the sta::or
is not mounted in
any additional frame or enclosure, as are conventional motors. A sheave 116 is
attached to a
shaft 118 and rotates within the frame members 100, 102 via standard be arings
120, 121.
The motor's rotor 114 is coiuiected to the shaft 118 and transmits the motor
torque. A disk
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brake 122 is mounted on the froiit end of the machine with a disk brake lin.ng
124. The disk
brake lining 124 is a double face lining having a first lining 124a and a
second lining 124b.
To affect a braking of the machine, the first lining 124a is applied to the
inner surface of the
disk 122 and the second lining is applied to the outer surface of frame
meniber 100.
Referring to Fig. 9, the spacing between the frame inembers 100, 102 is
realized by
two shoulders 126,128 of the connecting rods 104. The shoulders 126, 118 are
machined
onto the connecting rods 104 by increasing the diameter of the connecting rods
104 for a
length based on the width of the sheave 116. In an alternative embodimert, a
spacer bushing
(not shown) may be placed about each connecting rod between frazne mer ibers
100 and 102.
The spacer bushings are cylinders nZachi-iied from steel or other suitable rr
aterial having an
inside diameter and an outside diameter. The inside diameter of the spacer
bushing is larger
than the diameter of the connecting rod 104 such that the connecting rod J 04
passes through
the inside diameter of the spacer bushing_ The spacer bushings would then be
sized to a
length to a.ecommodate the width of the sheave 116.
Additional spacers 130 mounted on the connecting rods 104 allovN the coils 113
of tlie
stator 112 to have sufrcierit clearance from the innermost face of the rear
frame member 102.
Spacers 130 are cylinders machined from steel or other suitable material
liaving an inside
diaxneter and an outside diameter. The inside diameter of the spacer is 1a-ger
than the
diameter of the connecting rod 104 such that the connecting rod 104 pass:,s
through the inside
diameter of the spacer 130. Each eiid of a connecting rod 104 is threaclec: at
131 to
aecommodate nuts 132. Finally, nuts 132 are tightened on each end of tL e
connecting rods
104 in order to form a rigid assembly.
"f he sheave 116 can be desigiied to drive conventional sisal core i-opes,
synthetic ropes
or flat belts, among other suspension means, to fulfill modein elevator
rcquirements. In order
to adapt to this wide variety ofsu5peiision means thc sheave diameter can vary
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approximately 4 inches to approximately 21 inches and the sheave width from
approximately
1 1/2 inches to approximately 14 inches. Accommodation of such wide va iation
of sheave
diameters and widths is easily achieved with the present irrvention. By
changing the length of
the connecting rods 104, and the length of the shaft 118, any sheave width is
acceptable.
Additionally, the connecting rods 104 may be positioned at various locatio is
by placing the
coiuiecting rods in appropriate holes in the frame members 100, 102 so that no
interference
exists between the ropes (or- other suspension means) and any part of the rr.
achine for any
sheave diameter.
In addition to ropes, the present invention may be used witli other suspension
means
known in the art. For exarnple Fig. 5 through Fig. 8 show a machine built from
the teachings
of the present invention dri,,ing a flat belt 140.
Fig. 5 and Fig. 7 show two possible locations for positioning connccting rods
104 in
the lower portions of frame members 100, 102. In the A position, the
corniecting rods 104
are installed in the lower portions of frame members 100, 102 at a distance=
fronl the center
line of the shaft 118 such that the ropes, flat belts, or other suspension mez
ns pass inside the
connecting rods 104. In the B position, the connecting rods 104 are installed
in the lower
portions of fran-ie memhers 100, 102 are installed at a distance from the
center line of the
shaft 118 such that the ropes, belts, or other connecting means pass outsid,,
the coiulecting
rods 104. By adjusting the position of the connecting rods depending on t:ie
sheave diameter,
interference between the ropes, flat belt or other suspension means and the,
machine
supporting structure is avoided entirely.
Fig. 5 and Fig. 6 thus show an embodiment of the present invention where
connecting
ro.ds 104 mounted in the A position arc at a distance from the centerline
o:'shaft 118 which is
greater than the radius of the sheave 116 so that the flat beit 140 passes
in.3ide the connecting
rods 104.
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In the embodiment shown .in Fig. 7 and Fig. 8 the slicavc diamcter las bccn
increascd
and the lower connecting rods 104 are mounted in location B to avoid
interPerence with the
suspension means which could occur if the lower connecting rods were pla,:ed
at location A.
In this embodiment, the connecting rods 104 are at a distance from the
centerline of shaft 118
that is less than the radius of the sheave 116 so that the flat belt 140
passes outside the
connecting rods 104.
Because the oi-ily parts of the tnachule that need to be ehanged are
essentially of
cylindrical shape and can be machined on a CNC horizontal lathe, it is very
easy to adapt the
machine to any requirement as opposed to prior art where complicated part:;
need to be
changed, for example weldecl steel structures.
IC is also noted that in this invention the overall height of the machir:e
lias been
reduced by the entire height of the steel bedplate structure used in prior art
referred to as "H"
in Fig. I), which is a substantial advantage in the particular but very
popular instance of
"niachine room less" elevators.
In summary an innovative elevator gearless machine has been descr.bed and has
the
following advantages over the prior art:
Maximum flexibility: the machi.ne of the present invention can accommodate a
large
spectrum of sheave diatneters and sheave widtlis with iniiuniuni and
inexpensive changes
(position of connecting rods, length of connecting rods, shaft length).
Minimum number of parts: compression of motor frame and lower : teel structure
compared to that fouud in prior art.
Lower cost: expensivt; parts found in prior art such as cast iron pedestals or
massive
welded steel stnicttu-es have been replaced by lower cost components (fram ~:s
made out of
flame cut steel plates, connecting rods).
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Various changes can be made to the invention wilhouc departing Frcin the
spirit
thereof or scope of the fo.llowing claims.
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