U.S. patent number 3,822,542 [Application Number 05/387,277] was granted by the patent office on 1974-07-09 for swaged wire rope and method of manufacture.
This patent grant is currently assigned to Wire Rope Industries Ltd.. Invention is credited to John Raymond Naud, John H. Simpson.
United States Patent |
3,822,542 |
Naud , et al. |
July 9, 1974 |
SWAGED WIRE ROPE AND METHOD OF MANUFACTURE
Abstract
An improved swaged wire rope is produced by winding in a
predetermined manner a plurality of strands about a flexible core
of greater diameter than that of said strands and swaging the so
formed wire rope construction until a smooth, void-free exterior
surface of the rope is obtained. The new swaged wire rope is
particularly suitable for operations where abrasion, shock loading
and general rope abuse are prevalent.
Inventors: |
Naud; John Raymond
(Pierrefonds, Quebec, CA), Simpson; John H. (Dollard
des Ormeaux, Quebec, CA) |
Assignee: |
Wire Rope Industries Ltd.
(Pointe Claire, Quebec, CA)
|
Family
ID: |
4094115 |
Appl.
No.: |
05/387,277 |
Filed: |
August 10, 1973 |
Foreign Application Priority Data
Current U.S.
Class: |
57/215; 57/217;
57/218 |
Current CPC
Class: |
D07B
7/027 (20130101); D07B 5/10 (20130101); D07B
1/068 (20130101); D07B 5/007 (20130101); D07B
2201/2019 (20130101); D07B 5/005 (20130101) |
Current International
Class: |
D07B
1/06 (20060101); D07B 1/00 (20060101); D07b
001/06 (); D02g 003/36 () |
Field of
Search: |
;57/138,139,145,146,156,160,161,166,148 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Watkins; Donald E.
Attorney, Agent or Firm: Fleit, Gipple & Jacobson
Claims
We claim:
1. Swaged wire rope of integral construction having a flexible
central core supporting a plurality of strands wound around said
core, said core being of a larger diameter than that of the
surrounding strands and said strands being wound around said core
with a lay such that there remains about 1-1.5 percent gap between
the strands before swaging, and there is a reduction in diameter of
the rope of about 8 to 16 percent produced by swaging the entire
rope construction, sufficient to fill completely the gaps between
the strands and provide a smooth, void-free exterior surface.
2. Swaged wire rope according to claim 1, wherein said flexible
core is formed of a plurality of low carbon steel stranded wires
having a tensile strength of between 50,000 and 100,000 psi, and
said surrounding strands are formed of high carbon steel wires
having a tensile strength of between 200,000 and 300,000 psi.
3. Swaged wire rope according to claim 1, wherein said flexible
core is formed of a soft steel 19 wire seale center 9/9/1
construction having a tensile strength of between 60,000 and 80,000
psi and said surrounding strands are each formed of 26 wires of
hard steel having a tensile strength of between 250,000 and 270,000
psi.
4. Swaged wire rope according to claim 1, wherein said gap between
the strands is about 1 percent before swaging and there is a
reduction in diameter of the rope due to swaging of about 10-12
percent.
5. Swaged wire rope according to claim 1, having six strands
surrounding the core and having a reduction in diameter produced by
swaging of between about 10 and 15 percent.
6. Swaged wire rope according to claim 1, having eight strands
surrounding the core and having a reduction in diameter produced by
swaging of between about 9 and 12 percent.
7. Method of manufacturing swaged wire rope which comprises winding
a plurality of strands about a flexible core of great diameter than
that of said strands, the winding being carried out with a lay
factor of between 5 and 6 and in such a manner that there remains a
gap of about 1-1.5 percent between the strands surrounding said
core, and swaging the so formed wire rope construction up to a
total reduction in diameter between 8 and 16 percent, whereby the
gaps between said strands are completely filled and a smooth,
void-free exterior surface of the rope is obtained.
8. Method according to claim 7, wherein said strands are wound
around said core with a lay factor of about 5.7 and with a gap
between the strands of about 1 percent prior to swaging.
9. Method according to claim 7, for the manufacture of a
six-stranded rope, wherein six strands are wound around said core
and the wire rope is swaged up to a total reduction in diameter of
between about 10 and 15 percent.
10. Method according to claim 7, for the manufacture of an
eight-stranded rope, wherein eight strands are wound around said
core and the wire rope is swaged up to a total reduction in
diameter of between about 9 and 12 percent.
Description
This invention relates to a novel swaged wire rope and to the
method of producing same.
It is already known to produce various types of swaged wire rope.
For example, U.S. Pat. No. 3,457,718 issued July, 29, 1969 to John
C. Otto et al, discloses one method of manufacturing high density
wire rope by swaging a rope structure wherein each strand comprises
a plurality of wires stranded about a soft, pliant core of plastic
or the like. Such ropes, however, would have limited utility as
they cannot be used for operations which impart to the rope a great
deal of abuse, such as logging main lines, demolition ball cables,
towing cables and the like. This is, of course, due to the fact
that they comprise a plurality of soft, pliant cores of plastic or
similar material which will not withstand such abuse.
Another example is disclosed in U.S. Pat. No. 3,130,536 issued on
Apr. 28, 1964 to Vincent C. J. Peterson et al. According to this
patent, compacted wire rope is produced by swaging each strand
separately and then helically wrapping the strands about a core to
form the wire rope. There are several disadvantages to such
construction. The first is due to the fact that such wire rope is
not produced as an integral unit in a single swaging operation, but
every strand must be swaged separately. Thus, the swaging of each
strand must be carefully controlled to produce a final rope of
uniform strength and configuration. It is much more difficult and
expensive to swage each element separately and then put them
together, rather than swaging the wire rope in one single
operation. The other important disadvantage is that the swaged
strands are simply wrapped around the core and thus the core does
not participate, so to say, in the swaging process. The core
remains undeformed and in exactly the same shape as originally
used. This results in a non unitary construction which may provide
failures of the rope during abusive applications. It will also be
appreciated that good integral wrapping of the strands around the
core is extremely difficult to achieve in such circumstances, since
each strand has flattened slippery faces which may result in
irregular lays and slippages of the strand on the core during the
wrapping operation.
All these limitations and disadvantages are overcome or
substantially reduced by the present invention.
Thus, the principal object of the present invention is to provide a
novel swaged wire rope which will have an integral, compacted
construction and a smooth, void-free exterior surface and which
will have an excellent resistance to general abuse.
Another object of this invention is to provide a simple, efficient
and inexpensive method of manufacturing such swaged wire rope.
Other objects and advantages of the invention will be apparent from
the following more detailed description thereof.
Generally, there is provided in accordance with this invention a
swaged wire rope of integral construction having a flexible central
core supporting a plurality of strands wound around said core, said
core being of a larger diameter than that of the surrounding
strands and said strands being wound around said core with a lay
such that there remains about 1-1.5 percent gap between the strands
before swaging, and there is a reduction in diameter of the rope of
about 8 to 16 percent produced by swaging the entire rope
construction, sufficient to fill completely the gaps between the
strands and provide a smooth, void-free exterior surface.
A preferred swaged wire rope of this invention comprises a flexible
core formed of a plurality of low carbon steel stranded wires
having a tensile strength of between 50,000 and 100,000 psi whereas
the surrounding strands are formed of high carbon steel wires
having a tensile strength of between 200,000 and 300,000 psi. A
particularly preferred flexible core is formed of a soft steel 19
wire seale center 9/9/1 construction and has a tensile strength of
between 60,000 and 80,000 psi whereas the particularly preferred
strands wound around such center would each be formed of 26 wires
of hard steel having a tensile strength of between 250,000 and
270,000 psi.
When the strands are wound around the core, the preferred gap left
between the strands before swaging is of about 1 percent and the
preferred reduction in diameter of the rope due to swaging is of
about 10-12 percent.
The number of strands surrounding the core may, of course, vary
depending on the desired final rope construction. Thus, when a six
stranded rope is made, the preferred reduction in diameter due to
swaging will be between about 10 and 15 percent. On the other hand,
when an eight stranded rope is made, i.e., eight strands are wound
around the core, the reduction produced by swaging will preferably
be between about 9 and 12 percent. With even higher number of
strands, the reduction will be proportionally lower.
The method of manufacturing the novel swaged wire rope according to
this invention generally comprises winding a plurality of strands,
of the type described above, about a flexible core of greater
diameter than that of said strands, the winding being carried out
with a lay factor of between 5 and 6 and in such a manner that
there remains a gap of about 1-1.5 percent between the strands
surrounding said core, and swaging the so formed wire rope
construction up to a total reduction in diameter between 8 and 16
percent, whereby the gaps between said strands are completely
filled and a smooth, void-free exterior surface of the rope is
obtained.
The preferred lay factor is about 5.7 and the preferred gap between
the strands is about 1 percent prior to swaging.
At first glance, it may appear that the applicants have simply
taken a ready made wire rope and compacted it by a swager. This is
not at all the case. As a matter of interest, the applicants
originally tried such approach of simply taking a wire rope from
the finished stock and swaging the same to some degree. This
procedure has not produced the desired result, i.e., the desired
increase in the life of the rope and resistance to general abuse.
The fact is that when a finished rope is swaged to a reduction in
diameter of let us say 10 percent, there occurs substantial
deformation of the metal strands, and since in normal ropes there
is almost no gap between the strands, such swaging is accompanied
by substantial nicking and damaging of the individual strands, thus
adversely affecting the tensile strength and ductility of the final
rope.
Further tests and research revealed, however, that by providing a
central core which would be more flexible than the surrounding
strands which it supports, and which would be larger in diameter
than said strands, and by winding the strands around said core in
such a manner that there remains about 1-1.5 percent gap between
said strands, there is produced a greatly improved integral wire
rope when such construction is swaged to achieve a reduction in
diameter of between about 8 and 16 percent. These parameters have
been achieved after a great deal of testing and experimentation and
it is believed that they are essential to provide the extraordinary
improvements in performance produced by the new swaged rope.
By way of explanation, it is believed that when these conditions
are met, the swaging of the rope will not result in an undesirable
nicking and deformation of the individual strands within the rope,
but rather the deformed strands will fill the spaces left by the
gaps between them and to some extent will project into the more
flexible and larger core provided in the middle, thus forming a
smooth and tight overall construction of the wire rope.
The method of producing such swaged wire ropes is also essentially
novel. According to this method, the strands are wound about the
larger and more flexible core with a lay factor of between 5 and 6
and in such a manner that there remains a gap between the strands
of about 1-1.5 percent. Then, the so formed rope is swaged up to a
total reduction of between 8 and 16 percent, sufficient to fill
completely the gaps between the strands and provide a smooth,
void-free exterior surface.
It is well known to the man of the art that the lay factor of the
rope is the number which must be multiplied by the diameter of the
rope to give the lay of the rope. In normal non-swaged ropes the
lay factor is generally between 6 and 7. For example, 6.28 is a lay
factor used for many standard ropes.
It has been found, however, that such lay factors of 6-7, when used
before swaging, are not satisfactory for the swaged wire rope of
the present invention since after swaging they result in lays which
are too long and produce wire ropes which are insufficiently
flexible and which do not have a good smooth surface. On the other
hand, it has also been found that when the lay factor is too small
and the lay is therefore too short, one cannot get the reduction in
diameter which is desired and which results in the greatly improved
life and resistance to general abuse. Maintaining a proper lay in
the production of the novel swaged wire rope is therefore an
important feature of this invention.
The swaging operation as such is generally known and it consists in
deforming the wire rope by a succession of rapid hammer blows until
a desired reduction in diameter is achieved. There are many swaging
machines known in the art and it is not necessary to describe them
in detail. One such machine, which is suitable for the purposes of
the present invention, is described and claimed in U.S. Pat. No.
3,149,509 of Albert H. Oquist et al, issued Sept. 22, 1964.
The invention will now be further described with reference to the
appended drawings in which:
FIG. 1 is a general schematic plan-view illustration of a preferred
method according to the present invention for producing the novel
swaged wire rope;
FIG. 2 is a side view illustrating the novel swaged wire rope of
the present invention as it is produced;
FIG. 3 is an end view illustrating the same wire rope;
FIG. 4 is another side view drawn from a photograph and showing the
novel tight and smooth swaged wire rope construction of this
invention; and
FIG. 5 is an enlarged cross-section view drawn from a photograph
and clearly showing the cross-section of the novel swaged wire
rope.
As illustrated in FIG. 1, the swaged wire rope of the present
invention is produced in a simple, efficient and continuous
operation. Thus, core 10 is unwound from core pay-off 11 and is
forwarded through a middle guiding tube 12. Rope strands 14a, 14b,
14c, 14d, 14e and 14f are unwound from stand pay-offs 15a, 15b,
15c, 15d, 15e and 15f respectively and forwarded through guides 16
and guide sheaves 17 in six positions around tube 12 within which
passes the core. It should be noted that FIG. 1 is a plan view of
the arrangement and consequently some of the pay-off rolls are seen
only partially and some of the strands must be assumed to pass one
over the other.
Then, the core 10 as well as the strands 14 pass through a guide
plate 18 and the strands are suitably wound around the core within
die 19 by means of a rotating preforming head 20. As already
mentioned previously, the winding is carried out with a lay factor
of about 5-6 and in such a manner as to leave a gap of about 1-1.5
percent between the strands. These adjustments can easily be
carried out by men of the art.
Thereafter, the obtained rope passes through capstan 21 and is then
swaged by swager 22 up to a total reduction in diameter of between
8 and 16 percent.
Finally, the resulting swaged wire rope 23 is wound on a take-off
24.
This operation is efficient and economical and has proved effective
at speeds up to and exceeding 20 feet per minute. It should be
noted also that a light lubrication is called for at the stranding
operation. As far as the actual swaging operation is concerned, it
was found that a better swaged finish is obtained on surfaces which
have no lubrication at all. This, however, is not-suitable for most
wire rope applications and consequently the applicants prefer to
apply a very light coating of lubricant to the strands. In some
cases, it may be sufficient to lubricate the rope after it exits
from the swager, however, in such circumstances, the lubricant
usually does not sufficiently penetrate the swaged rope.
The obtained swaged wire rope 23 is illustrated in FIGS. 2, 3, 4
and 5. From FIG. 2 it will be seen that the various strands 25 are
in tight contact with each other and the wires forming these
strands have been flattened to exhibit smooth, flat and generally
uniform faces 26. The black edge sections 27 represent the
remainder of the lubricant on the rope as it exits from swager 22.
The final smooth and tight aspect of the rope is particularly well
illustrated by the photograph-like drawing of FIG. 4.
FIG. 3 shows an end or section view of a six stranded swaged rope
23 on a black background. It will be noted that in this particular
case, the core 28 is a soft steel 19-wire seale center having a
combination of wires 9/9/1. Its diameter is slightly greater than
that of the surrounding strands 25 which, in this case, consist of
a 26-wire strand construction made of hard steel. Strands 25 are
flattened so as to touch each other tightly on each side and to
project somewhat into the softer core 28 at the bottom, forming a
particularly tight and unitary combination as this is especially
well shown in the enlarged drawing of FIG. 5, where the rope end is
shown surrounded by an annular holding member.
The invention will now be further illustrated by means of the
following non limitative examples:
EXAMPLE 1
A swaged wire rope of 1/2 inch diameter has been produced in
accordance with the present invention. For this purpose a 9/16 inch
diameter six stranded wire rope was first made using a rope lay
factor of 5.7 and leaving a gap between the strands of about 1
percent. A 19 wire seale warrington strand core having a diameter
slightly greater than that of the strands was used for this
purpose. This core was made of soft steel (or low carbon steel)
having a tensile strength of 80,000-100,000 psi. The surrounding
strands were 26 wire strands of regular construction and were made
of hard steel (or high carbon steel) having a tensile strength of
250,000-270,000 psi. The rope was then swaged to 1/2 inch in
diameter, which represents a reduction of about 11 percent.
This rope was used for log skidder main lines and was compared with
a standard six stranded non-swaged rope of 9/16 inch diameter in
which the strands also consisted of 26 wires each and were made of
the same type of high carbon steel. The results are summarized
below:
Type of Rope Diameter Inches Breaking Strength (Lbs) Cost $ Average
Rope Life ______________________________________ Standard Rope
(High Strength) 9/16 33,500 34.10 4,000 trees Swaged Rope according
to this invention 1/2 32,000 34.10 10,000 trees
______________________________________
Other results measured on same or similar ropes both of six
stranded construction and of eight stranded construction have
clearly demonstrated that the swaged wire rope of the present
invention gives a minimum of 50 percent increase in rope life for
log skidder main line applications over standard ropes of similar
strength and cost.
EXAMPLE 2
A six stranded swaged wire rope of 1 inch diameter was produced in
accordance with the present invention again using low carbon steel
for the core strand and high carbon steel for the surrounding
strands. The initial diameter of the rope (prior to swaging) was
11/8 inch and it was reduced to 1 inch by swaging, which is a
reduction of about 12 percent. This wire rope was used for a
back-hoe in-haul and compared with standard non-swaged rope used
for the same purpose. The results were as follows:
Type of Rope Diameter Inches Construction Breaking Strength (Lbs)
Cost Average Life ______________________________________ Standard
Rope 1 6.times.25 Langs lay 89,600 $77.00 2.3 days Swaged Rope
according to this invention 1 6.times.26 123,000 $104.50 18 days
______________________________________
This result was obtained from a machine digging in exceptionally
hard ground, producing a shorter than normal life. The 18 days rope
life is an average of 12 ropes used to date.
It will be appreciated that although the cost of the swaged rope of
the present invention is about one-third higher than that of the
standard rope for this application, its average life is almost 8
times longer.
EXAMPLE 3
A swaged wire rope 7/8 inch in diameter was produced in accordance
with the present invention, with materials of the same type as in
Examples 1 and 2. It was compared with a standard non-swaged wire
rope 1 inch in diameter when used as a demolition ball hoist line.
The following results were obtained:
Type of Rope Diameter Inches Construction Breaking Strength (Lbs)
Cost $ Rope Life ______________________________________ Standard
Rope 1 6.times.25 Regular 89,600 $77.00 1 week Swaged Rope
according to this invention 7/8 6.times.25 94,000 $84.80 5 weeks to
date and still in service
______________________________________
This test was carried out at the Asbestos Mines in the province of
Quebec where fine blasting of the ore is unacceptable and
additional fragmentation of the ore is achieved through the use of
a 4 ton demolition ball on a 25 ton mobile crane unit. It will be
noted that although the cost of the swaged rope of the present
invention is slightly higher, its life is over five times longer
than that of standard ropes now used for such purposes.
In addition to the above non limitative examples, many tests have
been made with various swaged ropes produced in accordance with
this invention. Such ropes have been used as chokers, as grapple
loading system ropes, as grapple yarding system ropes, as skidder
main lines and are presently tried for purposes such as pile
driving ropes, shovel hoist ropes, boom suspension ropes, trawl
warps, elevator compensating ropes, pulp log conveyor ropes, and
the like. The present reports indicate that the swaged ropes of the
present invention when compared with standard ropes used for the
similar applications result in double rope life fairly consistently
and often result in outperforming the standard ropes five to one
and more. This surprising increase in the rope life for
applications where abrasion, bad winding, shock loading and general
rope abuse are prevalent was certainly not expected and should be
found of major advantage to the wire rope industry.
It should be noted that the illustrated and exemplified embodiments
discussed above are in no way limitative and that many
modifications can be effected by men familiar with the art without
departing from the spirit of the present invention and the scope of
the following claims. Thus, various types of cores and strands can
be used and the materials from which these cores and strands are
made can vary extensively, depending on the final application and
ultimate use of the wire rope. In the process of producing the
rope, various steps and conditions can be changed and adapted as
required for each individual case or application. Thus, the
invention is not limited to the specifically disclosed embodiments
but rather encompasses various changes and modifications that could
easily be carried out by men familiar with this art.
* * * * *