Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
DEVICE ASSEMBLY TO FORM LOOPS IN SLINGS
Document Type and Number:
WIPO Patent Application WO/2014/147493
Kind Code:
A2
Abstract:
A device assembly for forming loops on slings comprising : i) an adjustable vise device, ii) a bending arm device and iii) a threading manipulating device, and a method for forming loops on slings on said device.

Inventors:
PERCOSSI JUAN JOSÉ (AR)
Application Number:
PCT/IB2014/059077
Publication Date:
September 25, 2014
Filing Date:
February 18, 2014
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
IPH S A I C F (AR)
PERCOSSI JUAN JOSÉ (AR)
International Classes:
D07B7/16
Domestic Patent References:
WO1993014330A11993-07-22
WO2009093648A12009-07-30
Foreign References:
ES472014A11979-02-01
GB1097321A1968-01-03
US4043581A1977-08-23
US4572562A1986-02-25
US4843807A1989-07-04
US6170145B12001-01-09
US6381939B12002-05-07
US7568333B22009-08-04
Download PDF:
Claims:
What is claimed is:

1. A device assembly for forming loops on slings comprising :

i) an adjustable vise device,

ii) a bending arm device and

iii) a threading manipulating device.

2. The device assembly for forming loops on slings according to claim 1, wherein the adjustable vise device comprises a base column where a vise holder is mounted that supports the vise.

3. The device assembly for forming loops on slings according to claim 2, wherein the connection between the base column and the vise holder is made through a fixed column inside which there is a screw driven by a servomotor, wherein said screw allows the vise holder to be height adjusted by a nut and spindle mechanism comprised by a screw corresponding to the spindle and a nut connected to the vise holder that allows a vertical up and down movement of the vise holder that holds the vise.

4. The device assembly for forming loops on slings according to claim 3, wherein the vise holder that holds the vise moves up or down above the base column by a distance equal to the length of the screw inside the fixed column .

5. The device assembly for forming loops on slings according to any of the preceding claims, wherein the vise has two dies, a fixed die and a moveable die wherein the movement of the movable die is controlled by a hydraulic actuator .

6. The device assembly for forming loops on slings according to any of the preceding claims, wherein the vise is rotating on the horizontal plane.

7. The device assembly for forming loops on slings according to claim 6, wherein the rotating movement of the vise is performed by a servomotor which is located below the vise holder.

8. The device assembly for forming loops on slings according to claim 1, wherein the bending arm device is comprised by a flanged base where a fixed column is mounted, wherein on said fixed column the center arm can rotate horizontally with a circular movement connected to the fixed column through one end; the other end of the center arm is coupled to a swing arm, wherein said swing arm can rotate horizontally with a circular movement about said other end of the center arm; wherein the swing arm has in the longitudinal direction a rack on which a head moves comprised by a guided box connected to a threading nozzle having a tightening bolt.

9. The device assembly for forming loops on slings according to claim 8, wherein the threading nozzle can perform an angular movement about the vertical plane.

10. The device assembly for forming loops on slings according to claim 8, wherein the tightening bolt is controlled by a tightening bolt actuator.

11. The device assembly for forming loops on slings according to claim 9, wherein the angular movement about the vertical plane of the threading nozzle is controlled by a nozzle angular rotation servomotor.

12. The device assembly for forming loops on slings according to claim 8, wherein inside the guided box there is a shaft and pinion system controlled by a longitudinal movement servomotor allowing movement of said head along the rack of said swing arm when said pinion engages the rack .

13. The device assembly for forming loops on slings according to claim 8, wherein the horizontal circular rotation movement of the center arm and the swing arm is respectively controlled by a servomotor of the center arm and a servomotor of the swing arm.

14. The device assembly for forming loops on slings according to claim 1, wherein the threading device comprises a grasper, an upper arm and an arm mounted on a rotating base connected on a column, being the upper arm articulated relative to the arm and the arm articulated relative to the rotating base.

15. The device assembly for forming loops on slings according to claim 14, wherein the rotating base can rotate 360° in the horizontal plane about the vertical axis passing through the center of the column.

16. The device assembly for forming loops on slings according to claim 15, wherein the rotating movement of the rotating base is controlled by a servomotor located inside the column.

17. The device assembly for forming loops on slings according to claim 14, wherein the linkage of the upper arm with the arm comprises a fork configuration connected to the arm formed by two opposed ears and provided of a coaxial opening on each of the ears on the end of the arm closer to the upper arm, and a core with a coaxial opening aligned with said coaxial ear openings connected to the end of the upper arm closer to the arm so that to form a connecting shaft between the arm and the upper arm connected to the upper arm.

18. The device assembly for forming loops on slings according to claim 14, wherein the linkage of the arm with the rotating base comprises a fork configuration connected to the rotating base formed by two opposed ears and provided of a coaxial opening on each of the ears on the center of the rotating base, and a core with an axial opening aligned with said coaxial ear openings on the arm end closest to the rotating base so that to form a connecting shaft of the rotating base with the upper arm that is connected to the arm.

19. The device assembly for forming loops on slings according to claim 18, wherein the arm can perform a circular vertical movement of 180° about the connecting shaft of the rotating base with the arm.

20. The device assembly for forming loops on slings according to claim 17, wherein the upper arm can perform a circular vertical movement of 270° about the connecting shaft of the arm with the upper arm.

21. The device assembly for forming loops on slings according to claim 19, wherein the circular vertical movement performed by the arm is controlled by a servomotor aligned with the connecting shaft of the rotating base with the arm.

22. The device assembly for forming loops on slings according to claim 20, wherein the circular vertical movement performed by the upper arm is controlled by a servomotor aligned with the connecting shaft of the arm with the upper arm.

23. The device assembly for forming loops on slings according to claims 5, 7, 10, 12, 13, 16, 21 and 22, wherein the hydraulic actuator, the servomotor located under the vise holder, the screw servomotor, the tightening bolt actuator, the nozzle angular rotation servomotor, the longitudinal movement servomotor, the servomotor of the center arm, the rotating arm servomotor, the servomotor located inside the column, the servomotor aligned with the connecting shaft of the rotating base with the arm and the servomotor aligned with the connecting shaft of the arm with the upper arm, are controlled by Programmable Logic Controllers (PLCs) that make the servomotors and actuators reproduce movements according to previously defined parameters and loaded on programs to control the operation and repeating actions of each of the devices for forming loops on slings.

24. The device assembly for forming loops on slings according to the previous claim wherein the Programmable Logic Controllers (PLCs) are included in a control panel that allows to select or enter data to control the operation and repeating actions of each of the devices for forming loops on slings.

25. A method for forming loops on slings using the device assembly according to claim 24, comprising the following steps:

i) place the sling between the vise dies of the adjustable vise device so that a suitable length of steel rope of said sling exceeds said dies for forming the loop;

ii) adjust the dies to the working position by manually operating the hydraulic actuator from the control panel;

iii) select in the control panel the diameter of the sling to which the loop will be made whereby the following movements are produced on the bending device: the center arm and the swing arm are automatically positioned in the working position and the head moves on swing arm to the threading position;

iv) manually disassemble the sling steel rope between the dies in two branches, branch A - wire core containing three strands and branch B containing the remaining 3 strands.

v) thread branch A on the head nozzle of the bending arm;

vi) drive the tightening bolt to adjust the steel rope within the nozzle;

vii) press in the control panel the start of the operation whereby the Programmable Logic Controllers (PLCs) drive the longitudinal movement servomotor so that the head moves to the corresponding turning radius, then the servomotor of the swing arm so that the bending motion is made, tilting the nozzle to the corresponding locking angle and then letting the nozzle tilt laterally to accompany the torsion of the steel rope; thereby forming the loop; viii) manually disassemble the other branch B of the wire separating the three strands that make up the same;

ix) selecting a strand and adjust the grasper of the threading operating device to the end of said cord;

x) operate the threading operating device by the control panel, so as to guide the end of said strand inside the loop, repeat this operation for the other two strands engaging the initial branch A

xi) release the tightening bolt and rotate the center arm using a control in the control panel that actuates the servomotor of the center arm to release the work area;

xii) repeat steps ix) and x) , with the remaining steps, whereby the loop is completed;

xiii) if necessary, cut the excess wire at the beginning of the loop and twist around the sling wire (may or may not require to adjust the grip position of the vise for this operation) , to be later pressed with the cap; xiv) indicate in the control panel the end of operation whereby the threading manipulating device moves to the rest position;

xv) finish the job, pulling the sling with the loop finished between the adjustable vise dies and taking it to other place where the thimble is mounted, if applicable, and then place and press the cap to fasten the loop, whereby the device assembly for forming loops on slings is ready for another loop.

Description:
DEVICE ASSEMBLY TO FORM LOOPS IN SLINGS

OBJECT OF THE INVENTION

This invention refers to a device assembly to form loops for wire rope slings with a diameter from 1" to 3".

FIELD OF THE INVENTION

This invention refers to a device assembly that allows handling of wire rope slings with a diameter from 1" to 3", which comprise twisted strands of wire rope, in order to form loops; such operations so far are manually performed by the operator that involves a great effort because of the bending strength in short sections of such metallic slings.

The wire rope slings may be of two types, with loop only or with loop and thimble; the device assembly that allows handling wire rope slings with a diameter from 1" to 3" of this invention is designed especially to forming loops with thimbles which have smaller dimensions and thus a construction much more difficult.

BACKGROUND OF THE INVENTION

A sling is a length of a flexible and durable material, whether textile, made from synthetic fibers or wire rope.

Among the slings that can be manipulated to form loops, we refer especially those that are made of steel, in which the folding process is difficult with the increasing diameter of the sling steel rope.

In said wire rope slings the steel rope type most commonly used is right twisted with steel core with six or up to 16 outer strands, comprised from 7 up to 69 wires each one, according to the wire diameter to build the sling. Among the documents of the state of the art are:

The Spanish Patent ES 472,014 refers to a process for marking slings wherein a malleable metal sleeve crimped by a crimping operation on the loop of a sling wire is formed; in one of the forming shells of the sleeve, a small plate carrying on its surface the marks designed according to slots is introduced. By actuating the press, the plate is simultaneously formed and anchored by embossing on the sleeve. Forming and anchoring of the plate in the sleeve is performed simultaneously with the crimping of the sleeve on the sling wire.

British Patent GB 1,097,321 refers to a self adjustable sling that can be used to hold, suspend, lift or transport loads and more particularly to a sling that can be opened or closed quickly to release safely the sling around the load.

US Patent 4,043,581 A refers to an improved sling construction; the sling is formed or woven from a single steel rope in such a manner that it has an eye at each end thereof. The body includes three or more steel rope segments while each eye is formed by two sections or loops of the steel rope. Each eye includes one loop, made from a steel rope end section, which is a flemish eye and which has the end of the steel rope secured to one of the three body parts or steel ropes or by a pressed sleeve.

US Patent 4,572,562 A refers to a sling for lifting heavy objects by a hook or grapple suspended from a crane or other available lifting apparatus.

US Patent 4, 843, 807 A refers to a skein of yarn that is drawn through a protective tube prefabricated of a woven, tubular textile fabric that is connected in order to form a sling protection. The protective tube is formed of two length sections. These sections are of approximately the same size. US Patent 6,170,145 Bl refers to a method of securing a termination element to an end portion of a wire rope, the termination element having an elongated, ductile tubular sleeve portion, including the steps of positioning the end portion of a wire rope within the tubular sleeve portion, Pos itioning the s1eeve portion between co-acting dies , the dies having an opening that is non-circul r in cross- section, closing the dies a first time to deform the sleeve portion about the wire rope and into a non-circular external cross-section shape opening dies rotating the sleeve portion less than 180° closing the dies a second time to form the sleeve portion into a final external non- circular shape and opening the dies to remove the termination element.

US Patent 6, 381, 939 Bl refers to a wire rope sling- made of wire rope havi g a core and multiple strands of wire helically laid around the core and cut from a predetermined length. Approximately half of the strands of wire are separated from the core and the remaining strands of wire, shifted, relative to the core, a predetermined distance and rewoven with the core and remaining strands of wire into a continuous loop, A splicing sleeve surrounds first and second ends of the approximately half of the strands and a conti uous section of the core and remaining strands in a tightly engaged manner and another splicing sleeve surrounds first and second ends of the core and the remaining strands and a continuous section of the approximately half of the strands in a tightly engaged manner ,

US Patent 7,568,333 B2 refers to an apparatus for manufacturing industrial slings which is especially adapted for making round slings; the apparatus can make slings having one load-lifting core or multiple load-lifting cores. The apparatus has three primary sections and is applicable to non metallic slings.

SUMMARY OF THE INVENTION

An object of the invention is a device assembly for forming loops on slings comprising:

i) an adjustable vise device,

ii) a bending arm device and

iii) a threading manipulating device.

In the device assembly for forming loops on slings, the adjustable vise device comprises a base column wherein it is mounted a vise holder that supports the vise.

In the device assembly for forming loops on slings, the connection between the base column and the vise holder is made through a fixed column inside which there is a screw driven by a servomotor, wherein said screw allows the vise holder to be height adjusted by a nut and spindle mechanism comprised by a screw corresponding to the spindle and a nut connected to the vise holder that allows a vertical up and down movement of the vise holder that holds the vise.

In the device assembly for forming loops on slings, the vise holder that holds the vise moves up or down above the base column by a distance equal to the length of the screw inside the fixed column.

In the device assembly for forming loops on slings, the vise has two dies, a fixed die and a moveable die wherein the movement of the movable die is controlled by a hydraulic actuator.

In the device assembly for forming loops on slings, the vise is rotating on the horizontal plane.

In the device assembly for forming loops on slings, the rotating movement de the vise is made by a servomotor located under the vise holder.

In the device assembly for forming loops on slings, the bending arm device is comprised by a flanged base where a fixed column is mounted, wherein on said fixed column the center arm can rotate horizontally with a circular movement connected to the fixed column through one end; the other end of the center arm is coupled to a swing arm, wherein said swing arm can rotate horizontally with a circular movement about said other end of the center arm; wherein the swing arm has in the longitudinal direction a rack on which a head moves comprised by a guided box connected to a threading nozzle having a tightening bolt.

In the device assembly for forming loops on slings, the threading nozzle can perform an angular movement about the vertical plane.

In the device assembly for forming loops on slings, the tightening bolt is controlled by a tightening bolt actuator .

In the device assembly for forming loops on slings, the angular movement about the vertical plane of the threading nozzle is controlled by a nozzle angular rotation servomotor .

In the device assembly for forming loops on slings, inside the guided box there is a shaft and pinion system controlled by a longitudinal movement servomotor allowing movement of said head along the rack of said swing arm when said pinion engages the rack.

In the device assembly for forming loops on slings, the horizontal circular rotation movement of the center arm and the swing arm is respectively controlled by a servomotor of the center arm and a servomotor of the swing arm respectively.

In the device assembly for forming loops on slings, the threading device comprises a grasper, an upper arm and an arm mounted on a rotating base connected on a column, being the upper arm articulated relative to the arm and the arm articulated relative to the rotating base.

In the device assembly for forming loops on slings, the rotating base can rotate 360° in the horizontal plane about the vertical axis passing through the center of the column .

In the device assembly for forming loops on slings, the rotating movement of the rotating base is controlled by a servomotor located inside the column.

In the device assembly for forming loops on slings, the linkage of the upper arm with the arm comprises a fork configuration connected to the arm formed by two opposed ears and provided of a coaxial opening on each of the ears on the end of the arm closer to the upper arm, and a core with a coaxial opening aligned with said coaxial ear openings connected to the end of the upper arm closer to the arm so that to form a connecting shaft between the arm and the upper arm connected to the upper arm.

In the device assembly for forming loops on slings, the linkage of the arm with the rotating base comprises a fork configuration connected to the rotating base formed by two opposed ears and provided of a coaxial opening on each of the ears on the center of the rotating base, and a core with an axial opening aligned with said coaxial ear openings on the arm end closest to the rotating base so that to form a connecting shaft of the rotating base with the upper arm that is connected to the arm.

In the device assembly for forming loops on slings, the arm can perform a circular vertical movement of 180° about the connecting shaft of the rotating base with the arm .

In the device assembly for forming loops on slings, the upper arm can perform a circular vertical movement of 270° about the connecting shaft of the arm with the upper arm . In the device assembly for forming loops on slings, the circular vertical movement performed by the arm is controlled by a servomotor aligned with the connecting shaft of the rotating base with the arm.

In the device assembly for forming loops on slings, the circular vertical movement performed by the upper arm is controlled by a servomotor aligned with the connecting shaft of the arm with the upper arm.

Preferably in the device assembly for forming loops on slings the hydraulic actuator, the servomotor located under the vise holder, the screw servomotor, the tightening bolt actuator, the nozzle angular rotation servomotor, the longitudinal movement servomotor, the servomotor of the center arm, the rotating arm servomotor, the servomotor located inside the column, the servomotor aligned with the connecting shaft of the rotating base with the arm and the servomotor aligned with the connecting shaft of the arm with the upper arm, are controlled by Programmable Logic Controllers (PLCs) that make the servomotors and actuators reproduce movements according to previously defined parameters and loaded on programs to control the operation and repeating actions of each of the devices for forming loops on slings

In a preferred form of the invention, in the device assembly for forming loops on slings the Programmable Logic Controllers (PLCs) are included in a control panel that allows to select or enter data to control the operation and repeating actions of each of the devices for forming loops on slings .

Another preferred form of the invention comprises a method for forming loops on slings using the device assembly for forming loops on slings previously described.

Said method for forming loops on slings using the device assembly previously described, comprises the steps :

place the sling between the vise dies of the adjustable vise device so that a suitable length of steel rope of said sling exceeds said dies for forming the loop;

adjust the dies to the working position by manually operating the hydraulic actuator from the control panel;

select in the control panel the diameter of the sling to which the loop will be made whereby the following movements are produced on the bending device: the center arm and the swing arm are automatically positioned in the working position and the head moves on swing arm to the threading position;

manually disassemble the sling steel rope between the dies in two branches, branch A - wire core containing three strands and branch B containing the remaining 3 strands,

thread branch A on the head nozzle of the bending arm;

drive the tightening bolt to adjust the steel rope within the nozzle;

press in the control panel the start of the operation whereby the Programmable Logic Controllers (PLCs) drive the longitudinal movement servomotor so that the head moves to the corresponding turning radius, then the servomotor of the swing arm so that the bending motion is made, tilting the nozzle to the corresponding locking angle and then letting the nozzle tilt laterally to accompany the torsion of the steel rope; thereby forming the loop; manually disassemble the other branch B of the wire separating the three strands that make up the same;

selecting a strand and adjust the grasper of the threading operating device to the end of said cord;

operate the threading operating device by the control panel, so as to guide the end of said strand inside the loop, repeat this operation for the other two strands locking the initial branch A

release the tightening bolt and rotate the center arm using a control in the control panel that actuates the servomotor of the center arm to release the work area;

repeat steps ix) and x) , with the remaining steps, whereby the loop is completed;

if necessary, cut the excess wire at the beginning of the loop and twist around the sling wire (may or may not require to adjust the grip position of the vise for this operation) , to be later pressed with the cap; indicate in the control panel the end of operation whereby the threading manipulating device moves to the rest position;

finish the job, pulling the sling with the loop finished between the adjustable vise dies and taking it to other place where the thimble is mounted, if applicable, and then place and press the cap to fasten the loop, whereby the device assembly for forming loops on slings is ready for another loop.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1: shows each of the devices comprising the device assembly for forming loops on slings, identifying the adjustable vise device, the bending arm device comprising the center arm and the swing arm with the corresponding head, and the threading manipulating device; by arrows that show the types of movements made by each of the parts on each of the devices.

Figure 2: is an exploded view of the head corresponding to the bending arm device, wherein arrows indicate the types of movements made by each of the parts.

Figure 3: shows the first operation to be performed in the device assembly for forming loops on slings, said operation corresponds to placing and positioning the steel rope on the adjustable vise device.

Figure 4: shows the second operation to be performed in the device assembly for forming loops on slings corresponding to disassemble the steel rope in two branches .

Figure 5: shows the third operation to be performed in the device assembly for forming loops on slings corresponding to threading and positioning of the rotation radius .

Figure 6 : shows the fourth operation to be performed in the device assembly for forming loops on slings corresponding to branch "A" rotation and disassembly of branch "B".

Figure 7: shows the fifth operation to be performed in the device assembly for forming loops on slings corresponding to the first twisting step on the loop and releasing the arm.

Figure 8: shows the sixth operation to be performed in the device assembly for forming loops on slings corresponding to the following twisting steps. Figure 9: shows the seventh operation to be performed in the device assembly for forming loops on slings corresponding the last twisting step and removal of the threading manipulating device.

Figure 10: shows the final operation of the device assembly for forming loops on slings wherein the threading manipulating device is moved to a rest position.

Figure 11: shows the figures corresponding to the operations (a), (b) , (c), (d) and (e) to form a loop on a sling .

Figure 12: shows a sling indicating the loop length, loop width, sling diameter (0) and sling length. It also shows a table with the dimensions of the loop (length, width) for five diameters of the steel rope.

DETAILED DESCRIPTION OF THE INVENTION

The wire rope slings to be manipulated by the device assembly for forming loops on slings correspond to sling diameters ranging from 1" to 3", they generally comprise a central core and six strands twisted around of the same, we especially refer to those slings that are made of steel, in which the folding process is difficult with the increasing the diameter of the wire, in said the steel rope type most commonly used is right twisted with a steel core with six or up to 16 outer strands, comprised from 7 up to 69 wires each one, according to the wire diameter to build the sling .

So far, handling was done manually by operators, an increase in the cost of the product obtained was observed as high levels of production were not achieved due to conditions suffered by operators resulting from their physical efforts throughout the process that did not allow continuous production as rest periods were required. One way to solve the problems set out above comprises the use of the device assembly for forming loops on slings of this invention, the benefit of which lies in the reduction of the physical effort that the person must take to build the loops, the use of half the labor and the increase of production. Although the entire operation takes almost the same time that the traditional operation, the use of the device assembly for forming loops on slings of this invention achieves higher levels of production as operators do not need long breaks, improving, in this manner, production continuity.

The steps to be performed manually by the operator when forming loops on a sling in the conventional operation correspond to operations a), (b) , (c), (d) and (e) of Figure 11.

Such operations comprise:

(a) Disassembly of the steel rope into two parts, (a branch containing 3 strands and the other three strands and a core in the case of a sling comprised by 6 strands and a central core)

(b) Bending one of the branches (generally the branch with the core)

(c) First attaching step

(d) Weaving the sling by threading as follows (with large diameters, the branch is disassembled and strands are separately threaded)

(e) Set the cap to contain the loop closure (finally thimble is placed)

In order to eliminate the aforementioned drawbacks it is designed the device assembly to form loops in wire rope slings with a diameter ranging from 1" to 3" of this invention wherein operations can be performed in a semiautomatic way.

The device assembly for forming loops in wire rope slings with a diameter ranging from 1" to 3" comprises an adjustable vise device, a bending arm device and a threading manipulating device.

The adjustable vise device contains the adjustable vise itself, that is rotatable and adjustable in height and allows holding and optimum positioning of the steel rope to perform the operations to form the loops; this adjustable vise device is comprised by a base column where the vise holder is mounted, the connection between the adjustable vise holder and the base column is made through a fixed column inside which there is a screw driven by a servomotor, said screw allows the vise holder to be height adjusted, the vise itself is mounted on this movable support, as regards the height adjustment, it is performed by a nut and spindle mechanism comprised by a screw corresponding to the spindle and a nut connected to the vise holder. Its operation is such that if the nut is fixed, the rotating movement of the screw driven by the servo motor and controlled by a PLC moves the same longitudinally in height. This system allows converting the circular movement of the screw into a straight upward or downward movement of the nut connected to the vise holder which produces the height adjustment of the vise. In this upward or downward movement, the vice holder and therefore the vise, moves up or down above the base column a distance equal to the size of the screw inside the fixed column.

The vise itself is comprised by two dies, a fixed die and a moveable die.

By means of a hydraulic actuator which acts on the movable die that the dies can hold firmly the steel rope to work on.

This hydraulic actuator can be controlled by a PLC. In turn the vise is horizontally rotatable with respect to the vise holder by a servo motor located below the vise holder, (see Figure 1, upper right portion) . This actuator can be controlled by a PLC.

The bending arm device has a flanged base on which a fixed column is mounted, the center arm rotates horizontally on said fixed column with a circular movement that is mounted on the fixed column through one end, the circular movement of said center arm is caused by a servomotor which allows rotation and is located on the upper portion, centered on the fixed column.

In the other end of the center arm, there is another servomotor coupled to the swing arm, this servomotor allows rotation of the swing arm with center on the end of the center arm not connected to the fixed column. This drive can also be controlled by a PLC.

The swing arm has a rack that allows a head to move along its length, thereby a longitudinal movement servomotor is coupled to the pinion shaft inside a guided box, said pinion meshes on the rack and allows the head to move along said swing arm.

At the rear face of the head, a threading nozzle allows the attachment of a steel rope branch, this nozzle comprises an opening inside of the which the wire is placed, by a hydraulic actuator the steel rope branch is pressed when it is located inside so that to be secured inside the opening of the threading nozzle.

A second servomotor allows the angular rotation of said threading nozzle, which in turn rotates freely on its axis to a certain angle to match with the positioning of the wire (see Figure 1 to the left) . All servomotors of the bending arm device can be controlled by Programmable Logic Controllers (PLCs) included in a control panel that automate electromechanical processes to be carried out using suitable sensors to determine the positions of the elements belonging to the devices in every moment and make the servomotors work based on programmed instructions. The control panel allows inputting or selecting data so that the Programmable Logic Controllers start the operations. In this way, the selection or inputting data as to the wire diameter to handle in the control panel makes the PLCs command a response in the servomotors and actuators, wherein, once placed said steel rope on the vise, it adjusts the dies to the working position, and in the same way, both the center arm and the swing arm automatically position at the start position corresponding to that dimension and the head moves on the swing arm to the threading position. Said start position was initially determined empirically for each wire diameter, and the determined parameters loaded on the Programmable Logic Controllers (PLCs) which make the servomotors and actuators reproduce said start position according to the diameter of the wire to be processed.

The sole selection or entering the data as to the wire diameter in the control panel makes by the Programmable Logic Controllers that the hydraulic actuator closes the dies of the rotating vise with a pressure suitable to said selected wire diameter.

The threading device comprises a grasper, an upper arm and an arm mounted on a rotating base connected on a column, being the upper arm articulated relative to the arm and the arm articulated relative to the rotating base.

The arm is mounted on a rotating base on a column; this allows a complete turn of said arm by a servomotor which is included inside of the column.

On the rotating base there is the arm fork that is connected to an end of said arm, by another servomotor that allows said arm to make half a turn perpendicular to the rotating base. In the other end of the arm, there is the connecting shaft with the upper arm which has a 270 degree turn about this axis, wherein said movement is performed by means of a third servomotor. At the opposite end of the linkage of the upper arm and arm, there is the grasper that can rotate about its own axis and at the same time hold the steel rope to work on (see Figure 1, lower portion to the left) . The grasper can hold the steel rope being actuated by a hydraulic, pneumatic or mechanical means known in the art; in this case the two dies of the grasper hold the steel rope with an adequate pressure which prevents the same leaves said grasper.

The linkage of the upper arm with the arm comprises a fork connected to the arm formed by two opposed ears and provided of a coaxial opening on each of the ears on the end of the arm closer to the upper arm, and a core with a coaxial opening aligned with said coaxial ear openings connected to the end of the upper arm closer to the arm so that to form a connecting shaft between the arm and the upper arm connected to the upper arm.

The linkage of the arm with the rotating base comprises a fork configuration connected to the rotating base formed by two opposed ears and provided of a coaxial opening on each of the ears in the center of the rotating base, and a core with an axial opening aligned with said coaxial ear openings on the arm end closest to the rotating base so that to form a connecting shaft of the rotating base with the arm that is connected to the arm.

The arm can perform a circular vertical movement of 180 degrees about the connecting shaft of the rotating base with the arm while the upper arm can perform a circular vertical movement of 270 degrees about the connecting shaft of the arm with the upper arm.

Being connected to the upper arm the connecting shaft between the arm and the upper arm, any rotational movement transmitted to said connecting shaft between the arm and the upper arm will cause said vertical circular movement in the upper arm that can reach an amplitude of 270 degrees.

Being connected to the connecting shaft of the rotating base with the arm, any rotational movement transmitted to said connecting shaft of the rotating base with the arm will cause said vertical circular movement in the arm that can reach an amplitude of 180 degrees.

A servomotor aligned with the connecting shaft of the arm with the upper arm transmits to said axis the necessary rotation to perform said circular vertical movement in the upper arm that can reach an amplitude of 270 degrees.

Another servomotor aligned with the connecting shaft of the rotating base with the arm transmits to said axis the necessary rotation to perform said circular vertical movement on the arm that can reach an amplitude of 180 degrees .

The previous two servomotors can be controlled manually or by PLCs which make said servomotors to reproduce movements according to previously determined parameters and loaded on programs that control operation and repeating positions on the amplitudes of the vertical circular movement of the arm and the upper arm.

All the PLC that control the hydraulic actuator, the servomotor located under the vise holder, the screw servomotor, the tightening bolt actuator, the nozzle angular rotation servomotor, the longitudinal movement servomotor, the servomotor of the center arm, the rotating arm servomotor, the servomotor located inside the column, the servomotor aligned with the connecting shaft of the rotating base with the arm and the servomotor aligned with the connecting shaft of the arm with the upper arm are included in the adjustable vise device, the bending arm device and the threading device are included in a control panel that allows selection or data input to control the operation and repetition of actions on each of the devices to form loops on slings.

The control panel can also manually command the servomotors of all devices depending on the tasks such that the process, if desired, is not performed automatically.

To form one loop on a sling, the first operation (OPERATION 1) to perform in the device assembly for forming loops on slings comprises setting and positioning the steel rope, in this operation, the operator places the steel rope in the vise dies of the adjustable vise device and adjust the vise dies to the selected working position or enters in the control panel the wire diameter (an alternative would be setting the steel rope between the adjustable vise dies and adjust them on the steel rope to process, sensors located at the adjustable vise send information to a PLC of the control panel automatically determining the wire diameter to be processed causing the necessary operations to process the steel rope) , the steel rope is placed in the dies such that a suitable sling portion protrudes to form the respective loop.

The minimum portion to protrude from the dies can be calculated based on the following table of dimensions of the loops according to the wire diameter:

TABLE

Said dimensions (length and width) as well as the wire diameter on a sling are also shown in Figure 12.

Considering the shape of a loop as the binding to a semicircle to the hypotenuse of two right triangles linked by the same vertex and the lower leg, it is possible to determine by the Pythagorean theorem the minimum length of the sling protruding from the die to form the loop, said length i calculated by the formula: wherein LENGTH corresponds to the loop LENGTH and WIDTH corresponds to the loop WIDTH.

The factor 7/5 which affects the final term considers steel rope lengths that remain inside the cap when the loop is completed.

In this operation, the operator in charge selects in the control panel the wire diameter to work on, which causes a response at the servomotors and actuators, so that, once said steel rope is placed on the vise of the adjustable vise device, the vise adjust its dies to the working position, and also, at the bending arm device, both the center arm and the swing arm are automatically positioned at the start position corresponding to such selected diameter and the head moves on the swing arm until reaching the optimal location of threading. This start position (determined empirically for each wire diameter) is programmed on the PLCs that control the servomotors and actuators so that said start position is reproduced according to the wire diameter to be processed.

Figure 3 shows this first operation (OPERATION 1) wherein selection or entering the wire diameter to be processed in the control panel causes the movement of the head on the swing arm to the threading position (see 1 in Figure 3) and also the center arm and the swing arm are placed in the appropriate position to start forming the loop in the sling. In this operation the threading position has been empirically determined for each wire diameter and programmed on the PLCs of the control panel so that the single input or selection of the wire diameter causes movement of the head and the optimal location of the swing arm and the center arm.

The second operation (OPERATION 2) to perform in the device assembly for forming loops on slings comprises manually disassembling in two branches the wire.

Steel ropes for slings with a diameter ranging from 1" to 3" generally comprise a central core and six strands twisted around of the same, in this case the separation into two branches (branches A and B in Figure 4) comprises manually disassembling said steel rope by the operator; wherein one of the branches (branch A) will contain the core together with three strands and the other branch (branch B) the three remaining cords.

By separating the two branches, branch A is manually threaded on the head nozzle of the bending arm device (shown as 2 in Figure 4) and the tightening bolt is actuated to fix branch A to the nozzle; adjustment of the tightening bolt at the nozzle is made by an tightening bolt actuator, this adjustment can be done manually or controlled by a PLC that controls said tightening bolt actuator .

The third operation (OPERATION 3) corresponds to positioning the rotating radius.

In this operation the operator in charge starts the automatic operation in the control panel.

The head of the bending arm device moves to the corresponding turning radius (3) by moving the guided box through the rack by the longitudinal movement servomotor, said turning radius position is determined by a PLC that responds to the start command of the automatic operation inputted by the operator in the control panel.

Then the swing arm begins its bending movement (4) to a determinate position, in this case the position is achieved by the action of the actuator that controls the swing arm of the bending arm device, said position is determined by a PLC that in response to the completion of the head displacement, makes the servomotor that controls movement of the swing arm to perform the bending movement (4) to form the corresponding loop. During said movements the threading nozzle tilts to the corresponding engagement angle; to accompany the torsion of the wire, the nozzle inclines laterally. (6) . Movements to perform by branch A are shown in Figure 5.

The fourth operation (OPERATION 4) corresponds to rotation of branch A and disassembly of branch B.

Once branch rotates A, the other branch B is manually disassembled by the operator that protrudes from the vise dies of the adjustable vise device, separating the strands that comprise the same. This operation is shown in Figure 6.

The fifth operation (OPERATION 5) corresponds to the first twisting step on the loop and releasing the arm.

In this operation the operator actuates the threading device to pass each of the strands through the loop thus engaging the initial branch A. In this operation the grasper holds the end of one of the strands and passes through the loop moving the rotating base, the arm, the upper arm and the grasper controlled by the corresponding servomotors. Said movement can be controlled by a PLC associated to a lever type control mechanism or joystick. Once completed the first step, the tightening bolt is released and the center arm is rotated to release the work area . The sixth operation (OPERATION 6) corresponds to the steps following twisting.

In this operation each of the strands passes through the loop whereby said loop is completed. Finally, the excess wire is cut at the beginning of the loop (if necessary) and it is twisted about the sling wire to later position and press the cap.

The seventh operation (OPERATION 7) corresponds to moving the threading manipulating device to the rest position by setting end of operation in the control panel.

The eighth operation (OPERATION 8) corresponds to end of operation, the sling with the loop thus completed is removed from the adjustable vise dies and is taken to another place where the thimble is mounted, the caps is positioned and pressed to fix the loop== whereby the device assembly for forming loops on slings is ready to form a new loop .

While the present invention has been described in connection with preferred embodiments with reference to the accompanying drawings, it should be noted that various changes and modifications are apparent to those skilled of the art. Such changes and modifications are to be understood as included within the scope of this invention as defined in the appended claims, unless they depart from them .