Information
-
Patent Grant
-
6695098
-
Patent Number
6,695,098
-
Date Filed
Friday, January 21, 200024 years ago
-
Date Issued
Tuesday, February 24, 200420 years ago
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Inventors
-
Original Assignees
-
Examiners
-
CPC
-
US Classifications
Field of Search
-
International Classifications
-
Abstract
A termination for an elevator tension member is provided that terminates a load with frictional forces created by wrapping the tension member about a body and with compressional forces generated by the weight of the load compressing the tension member upon itself.
Description
BACKGROUND OF THE INVENTION
The present invention relates to elevator systems. More particularly, the invention relates to various embodiments for terminating a tension member.
A conventional traction elevator system includes a car, a counterweight, two or more tension members interconnecting the car and counterweights, terminations for each end of the tension members at the connection points with the car and counterweights, a traction sheave to move the tension members, and a machine to rotate the traction sheave. Alternatively, 2 to 1 roping configurations are also common and typically include a car, a counterweight, two or more tension members interconnecting the car and counterweights, terminations for each end of the tension members at structural support points, a traction sheave to move the tension members, idler sheaves to interconnect the counterweight, the car and the traction sheave, and a machine to rotate the traction sheave.
The tension members have traditionally been formed of laid or twisted steel wire. Termination of such tension members at the car and counterweight in a traction elevator system, or, alternatively, at the structural support points for a 2 to 1 roping configuration elevator system, is conventionally effectuated by means such as compression terminations and wedge terminations.
Compression terminations of the prior art, which have been employed for ropes with an aspect ratio of one (round) and ropes with an aspect ratio of greater than one (flat) provide a reasonably broad range of pressures. However, even a simple compression termination requires multiple components, thereby making such a termination device relatively expensive to manufacture and time consuming to install. Wedge-type termination devices have also been employed for both round and flexible flat tension members and are effective, yet remain relatively expensive to manufacture.
Furthermore, with conventional termination devices, the pressure or holding force is exerted upon a portion of the tension member or rope equivalent in length to the holding surface of the device. Thus, for effective holding force, the length of the holding surface must be great enough to maintain the load.
Thus, the art is still in need of a reliable termination device that reaches an advantageous price point, is easy and timely to assemble, is easy and timely to disassemble and decreases clearance requirements.
SUMMARY OF THE INVENTION
The termination device of the present invention is a body having a particular configuration which facilitates a tension member being wrapped therearound for termination. In one embodiment, one end of the tension member is inserted in an aperture upon the body. The insertion does not intentionally hold any of the load force of the tension member (from a car or counterweight hanging thereon) but merely retains the tension member in position while the member is being wrapped around the termination device. The tension member is terminated (i.e., maintained in position during its working life) by friction of the tension member against the termination device (in the first wrap) and by a clamping force on the tension member provided by the member itself as it overlaps the first turn in the second partial wrap of the tension member through the clamping force and the frictional forces produced, all of the load force is reacted out of the system before reaching the end of the termination member inserted in the aperture.
In a preferred embodiment of the present invention, the body has a cylindrical surface.
The device of the present invention reliably terminates a tension member while using less material and requiring less clearance.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawings wherein like elements are numbered alike in the several FIGURES:
FIG. 1
is a perspective view of an elevator system;
FIG. 2
is a perspective view of a termination assembly of the present invention;
FIG. 3
is a side elevation view of the termination assembly of
FIG. 2
;
FIG. 4
is a front elevation view of the termination assembly as depicted in
FIGS. 2 and 3
;
FIG. 5
is a side elevation view of an alternative embodiment of a termination assembly of the present invention;
FIG. 6
is a front perspective view of another alternative embodiment of a termination assembly of the present invention;
FIG. 7
is a front perspective view of a body within the termination of
FIG. 6
;
FIG. 8
is a side elevation view of a body of
FIG. 7
;
FIG. 9
is a front elevation view of a body shown in
FIGS. 7 and 8
;
FIG. 10
is a side elevation view of a support of the termination shown in
FIG. 6
;
FIG. 11
is a front elevation view of the support of
FIG. 10
;
FIG. 12
is a side cross-sectional view of the termination of
FIG. 6
; and
FIG. 13
is a side cross-sectional view of another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to
FIG. 1
, the relative location of the tension member termination device of the invention can be ascertained. For clarity, an elevator system
12
is illustrated having a car
14
, a counterweight
16
, a traction drive
18
and a machine
20
. The traction drive
18
includes a tension member
22
interconnecting car
14
and counterweight
16
which member is driven by a sheave
24
. Both ends of tension member
22
, i.e., a car end
26
and a counterweight end
28
must be terminated. It is either of these termination points for a tension member with which the present invention is concerned. An exemplary tension member of the type contemplated in this application is discussed in further detail in U.S. Ser. No. 09/031,108 filed Feb. 26, 1998 entitled Tension Member For An Elevator and U.S. Ser. No. 09/218,990 also entitled Tension Member For An Elevator and filed Dec. 22, 1998, both of which are entirely incorporated herein by reference. Further, laid or twisted steel wire and conventional rope tension members may be accommodated with the termination system of the present invention. The elevator system depicted is provided solely for exemplary purposes to illustrate the location of the termination of the invention. Other elevator arrangements, such as a 2 to 1 roping configuration, may readily employ the termination detailed herein at the stationary support structures without departing from the invention. Therefore, when reference is made to a car end
26
and counterweight end
28
, corresponding stationary support ends may be substituted thereby adapting the present description with a 2 to 1 roping configuration elevator system, as the location of the termination is irrelevant to the invention detailed herein.
An embodiment of a termination of the present invention will now be described with reference to
FIGS. 2
,
3
and
4
, wherein
FIG. 2
is a perspective view of termination device
30
,
FIG. 3
is a side cross-sectional view of termination device
30
and
FIG. 4
is a front elevation view of termination device
30
. Termination device
30
includes a central body
32
having a generally cylindrical surface, including an aperture
34
traversing body
32
. It is to be understood that body
32
may be a right circular cylinder, an elliptical cylinder or other shaped bodies.
For connection to car
14
or counterweight
16
, a support
36
having sockets
38
with apertures
40
is integrally molded or cast with body
32
for passage of a shackle (not shown) or other means of attaching termination device
30
to a dead end hitch (not shown). A view of body
32
behind the support
36
is depicted in phantom. A tension member or rope
22
is wrapped around body
32
having one end inserted within aperture
34
and an opposing end extending away from termination device
30
for holding the load (car or counterweight).
Referring now to
FIG. 3
, a side elevation view of the termination device is provided. Aperture
34
commences generally at an outer surface of body
32
and ends generally centrally within body
32
. Tension member
22
having a car end
26
and a counterweight end
28
is also depicted as having one of the ends
26
,
28
inserted into aperture
34
, and tension member
22
is wrapped (counterclockwise in the drawing) around the circumference of body
32
past aperture
34
and over itself and continuing to either the car
14
or counterweight
16
. Frictional forces exist at the interface of the tension member
22
and the walls of aperture
34
and the outer surface of body
32
. These forces react out the load on the tension member. The higher the coefficient of friction available between tension member
22
and body
32
, the greater the holding assistance from the friction. The termination device
30
is further enhanced by causing the tension member to provide its own clamping force. More specifically, the desired wrap of tension member
22
over itself creates the clamping force on the first wrap which assists in holding the load. In a specific embodiment, tension member
22
is preferably wrapped about the circumference of body
32
at least 1½ times to provide a greater surface area of frictional contact and to allow the weight of car
14
or counterweight
16
to compress and hold tension member
22
upon itself. Force F is generated by the weight of car
14
or counterweight
16
on the tension member
22
. In a preferred embodiment, the termination device is arranged so that the body
32
at the point where force F is tangent to body
32
at the point where the overlap of tension member
22
ends (about 1½ turns).
This arrangement provides maximum compressional forces on the overlapped section of tension member
22
. Additionally, there is a high coefficient of friction between the overlapped portions of tension member
22
. The termination device as taught is beneficial to the art since it requires less overall height. This is in part because the holding surface area is increased due to multiple wraps.
Still referring to
FIGS. 2
,
3
and
4
, apertures
40
within the socket
38
of support
36
provide a channel through the top portions of support
36
, for passage of a shackle, for example. Further, in the embodiment described, a space is provided generally centrally with respect to body
32
. Termination device
30
may be cast with such a gap as to minimize materials and associated expenses, decrease mass and allow for a shackle or hitch to be installed therein.
Adjustment may be provided for in the embodiment detailed with reference to
FIGS. 2-4
by tightening or loosening a member cooperating with the shackle (not shown), for example, the dead end hitch.
Aperture
34
may be entirely eliminated if desired with the result being slight increase in difficulty in installing the device. It should also be noted that the configuration for aperture
34
may be varied. For example, aperture
34
may be open at each end of body
32
(as shown), thereby allowing tension member
22
to be inserted from either end. Further aperture
34
is depicted in the embodiment described as being parallel to the edges of body
32
and generally at the outermost curved portion of body
32
. However, it may be arcuate, sloped, V-shaped, Z-shaped, S-shaped or in the form of some other continuous line. Additionally, aperture
34
may be closed on one end of body
32
and open on the opposite end of body
32
. This will allow tension member
22
to be inserted in the lengthwise direction from the end of body
32
having access to aperture
34
. Additionally, aperture
34
may be an anchor hole or an anchor slot in which an end
26
or
28
of tension member
22
is inserted. The shape and configuration of aperture
34
may vary, depending on factors such as the ease of access desired and the type of tension member
22
employed (i.e., an aspect ratio of one or an aspect ratio of greater than one).
Referring now to
FIG. 5
, a side cross-sectional view of another embodiment of a termination device
30
is provided. An end
26
or
28
of tension member
22
is inserted into aperture
34
of body
32
, and tension member
22
is wrapped around the circumference of body
32
. Instead of wrapping directly upon another portion of tension member
22
, however, a plate
40
is included. Plate
40
is arcuate to conform to the circumference of body
32
, and is preferably semi- or quarter-circular.
When a force F acts on tension member
22
, compressive forces normal to the concavely arcuate surface formed by the winding of tension member
22
are created. These compressive forces act normal to the convex arcuate surface of plate
40
and body
32
around which tension member
22
is wound. Furthermore, the compression of tension member
22
on plate
40
and body
32
creates frictional forces between tension member
22
and body
32
as well as between tension member
22
and plate
40
. These frictional forces enhance the holding power of tension member
22
.
Plate
40
may be compliant so as to contact and conform to the shape of the layer formed by tension member
22
wound on body
32
immediately below plate
40
. Sandwiching plate
40
between two layers of tension member
22
creates additional frictional forces between plate
40
and tension member
22
to further enhance the holding power of tension member
22
.
Moreover, utilizing a fireproofed plate
40
to separate the layers of tension member
22
wound on body
32
provides additional fire protection for termination device
30
. In such a configuration, a polyurethane layer disposed on tension member
22
may melt or soften sufficiently to enable the steel ropes of tension member
22
to cut through the polyurethane layer, thus allowing the steel ropes of all layers of tension member
22
to group together on the convex arcuate surface of body
32
. Plate
40
ensures that in the event of a fire, tension member
22
remains configured in multiple layers and that frictional forces continue to be exerted on tension member
22
, thus allowing termination device
30
to maintain its structure integrity.
Additionally, multiple plates
40
may be arranged if tension member
22
is to wrap more than one and one half times around body
32
.
It may be desirable to provide a convenient adjustment mechanism for tension member
22
to increase or decrease its length. An additional configuration providing adjustment for a termination member is depicted in
FIGS. 6-12
.
FIG. 6
is a front perspective view of a termination
60
;
FIG. 7
is a front perspective view of a body
62
within termination
60
;
FIG. 8
is a side elevation view of body
62
shown in
FIG. 7
;
FIG. 9
is a front elevation view of body
62
shown in
FIGS. 7 and 8
;
FIG. 10
is a side elevation view of support
84
of termination
60
;
FIG. 11
is a front elevation view of support
84
shown in
FIG. 10
; and,
FIG. 12
is a side cross-sectional view of termination
60
. The various
FIGS. 6-12
are used collectively to detail this embodiment of the invention.
Termination
60
includes a body
62
having a generally cylindrical surface seated within a support
84
(partially shown in phantom). Tension member
22
is wrapped around body
62
as described above with reference to the embodiment depicted in
FIGS. 2-4
, and extends through support
84
. Body
62
locks the opposing end of tension member
22
via the frictional forces between tension member
22
and the surface of body
62
, the frictional forces between overlapping layers of tension member
22
and the compressional forces of the overlapping layers of tension member
22
from the weight of the load (i.e., car or counterweight). In the embodiment detailed with reference to
FIGS. 6-12
, body
62
includes an aperture
64
for accepting an end of tension member
22
. As with the embodiment described above with reference to
FIGS. 2-4
, the orientation, direction, and configuration of aperture
64
may vary. Also, aperture
64
may be completely eliminated.
Support
84
further includes holes
98
that are integrally molded or cast within sockets
96
for passage of a shackle (not shown) or other means of attaching termination
60
to a dead end hitch (not shown).
Body
62
is maintained within support
84
by an elongated pin inserted through hole
102
of support
84
and bore
66
of body
62
. Rotation of body
62
is prevented as described herein by a series of cutouts
68
at the ends of body
62
. Cutouts
68
provide four inside corners that are generally symmetrical about the center of the circular end of body
62
. A lock portion
88
, complementary in size, shape and position to cutout
68
, generally formed as an outside corner, is provided within support
84
. One of the pluralities of cutouts
68
of body
62
rests upon lock portion
88
. In this manner, when body
62
is seated upon lock portion
88
and an elongated pin is inserted therethrough, body
62
is supported while being prevented from rotation. When it is desired to increase or decrease the length of tension member
22
, the elongated pin is removed from body
62
and body
62
is rotated in the appropriate direction to take up or release tension member
22
and a cutout
68
is aligned with and seated upon lock portion
88
.
It is understood by those skilled in the art that the relation between cutouts
68
and block portion
88
may vary. For example, instead of providing a series of cutouts
68
in the form of inside corners and corresponding block portion
88
in the form of an outside corner, a reverse configuration is possible. Referring to
FIG. 13
, for example, a side cross-sectional view of another embodiment is provided. In place of cutouts
68
and block portion
88
of
FIGS. 6-12
, the embodiment shown in
FIG. 13
employs a series of outside corners
128
and lock portion
148
in the form of an inside corner disposed upon support
84
(not shown). Adjustment is effectuated in the same manner as described with reference to
FIGS. 6-12
.
While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.
Claims
- 1. An elevator tension member termination device comprising:a body having an outside surface of a predetermined coefficient of friction; and a support structure associated with said body, said support structure being attachable to a separate member, said support structure being positioned such that a tension member wrapped at least 1½ times around said body is positioned to hold a load tangent to said body at a point on said tension member where it has overlapped itself at least ½ times.
- 2. A termination device as in claim 1, further comprising a socket depending from the body for attaching the body to a load or a support structure.
- 3. A termination device as in claim 1, wherein the body includes an aperture to accept an end of a tension member.
- 4. A termination device as in claim 3, wherein the aperture is selected from the group consisting of a hole, a straight slot, an arcuate slot, a V-shaped slot, a S-shaped slot and a Z-shaped slot.
- 5. A termination device as in claim 1, wherein the body comprises a cylindrical surface.
- 6. A termination device as in claim 1, wherein the body is oval in cross sectional shape.
- 7. A termination device as in claim 1 wherein the body and support structure are disassociate and associable in various angular relationships through engageable members thereon.
- 8. A termination device as in claim 1 wherein the body and support structure each include a lock portion which are engageable with each other in a plurality of positions, said positions being selectable by a user.
- 9. An elevator system including a car suspended by a rope, the rope having an aspect ratio greater than one, wherein aspect ratio is defined by the ratio of rope width to rope thickness, the elevator system including a rope termination having a body, and wherein the rope is terminated by wrapping the rope around the body such that the rope is retained to the body by frictional forces between the body and the rope and by frictional and compression forces between layers of the rope wrapped around the body.
- 10. The elevator system according to claim 9, wherein the rope includes a load-carrying member encased within a jacket formed from non-metallic material.
US Referenced Citations (6)
Foreign Referenced Citations (2)
Number |
Date |
Country |
36 23 407 |
Jan 1988 |
DE |
2287447 |
Sep 1995 |
GB |