Modification of pelvic chair with brake support device for descent in

personnel of the Colombian national army

..........................................

Modificación de silla pelvica con dispositivo de apoyo al freno para descenso en

personal del ejército nacional de Colombia

Juan Gabriel Rojas Gonzalez

Jorh Alexander Díaz Tovar

Mónica Estefanía Hernández García

Julian Enrique Barrero García

Nathalie Tarazona Rojas

ABSTRACT

This research article arises from the modified

pelvic chair project with brake support device

for descent, this project is carried out based on

the experiences of contingencies presented in

the first man at the time of descending in the

Air Assault tower of the National Army of

Colombia, seeking to reduce the risk of user

accidents, implementing a braking device that

consists of the adaptation of a carabiner

located at a specific point of the pelvic chair,

being a fixed point with greater adaptability

and anchoring security, allowing to continue

with the tasks they are performing, giving

orientation and control to the rope, avoiding

knots due to oscillation when releasing the

brake rope.

Key words: Descent, support device, national

army, pelvic chair

Received: November 13, 2023

Approved: December 15, 2023

...........................................

Decano, Militar de Suboficiales “Sargento

Inocencio Chincá, https://orcid.org/0000-0001-

6294-278X

unidadinvestigacion@emsub.edu.co

Oficial de Ciencia y Tecnología

Escuela Militar de Suboficiales “Sargento Inocencio

Chincá”, https://orcid.org/0000-0002-5541-947X

unidadinvestigacion@emsub.edu.co

Ingeniera Civil, Especialista en Gerencia de

Proyectos, Asesora de Investigación

Escuela Militar de Suboficiales “Sargento Inocencio

Chincá” https://orcid.org/0000-0001-9802-2897

Investigador.presupuesto@emsub.edu.co

Ingeniero Industrial, Magister en Educación,

Director de Investigación

Escuela Militar de Suboficiales “Sargento Inocencio

Chincá”, https://orcid.org/0000-0003-2143-9461

Julian.barrero.profesor@emsub.edu.co

Ingeniera Eléctrica, Especialista en Gerencia de

Proyectos, Maestrante en Innovación y Tecnologías

para la Educación

Docente ESAVE, Escuela Militar de Aviación,

https://orcid.org/0000-0002-2113-4724

nathalietarazona@cedoc.edu.co

Modification of pelvic chair with brake support device for descent in personnel of the Colombian national army

Vol 4 - No 1 January - June e-ISSN 2745-1194 Pages 21- 29

RESUMEN

El presente artículo de investigación surge del

proyecto silla pélvica modificada con

dispositivo de apoyo al freno para descenso,

este proyecto se realiza con base en las

experiencias de contingencias presentadas en

el primer hombre al momento de descender en

la torre de Asalto Aéreo del Ejército Nacional

de Colombia, buscando reducir el riesgo de

accidentalidad del usuario, implementando un

dispositivo de freno que consiste en la

adaptación de un mosquetón ubicado en un

punto específico (parte lateral pierna izquierda

o derecha) de la silla pélvica, siendo un punto

fijo con mayor adaptabilidad y seguridad de

anclaje, permitiendo continuar con las tareas

que estén realizando, dando una orientación y

control a la cuerda, evitando nudos por

oscilación al soltar la cuerda de freno.

Palabras Clave: Descenso, dispositivo de

apoyo, ejército nacional, silla pélvica.

Introduction

The Air Assault School trains officers, non-commissioned officers and professional

soldiers of the Colombian Armed Forces in the planning, development and execution

of air assault operations with emphasis on jungle, combining strategic speed with the

tactical mobility of air elements. As a specialty, they have the maneuvers of insertion

and extraction of personnel in the most remote and jungle areas of Colombia. This

implies the descent from helicopters by means of ropes, which generates a risk for the

descending personnel, especially for the first man, for not having the support of the

rope master on the ground.

The Air Assault School of the Military Forces of Colombia, seeks to specialize military

personnel in the highest tower in South America, so that the user socializes with the

tower and lose the fear, with the above, at the time of certifying them in aircraft

Modification of pelvic chair with brake support device for descent in personnel of the Colombian national army

Vol 4 - No 1 January - June e-ISSN 2745-1194 Pages 21- 29

through a simulation of a normal operation, the military can perform their exercise

without any contingency.

In order to continue training military personnel by seeking continuous improvement

of both units and equipment in the training and training of special forces, descent

training is carried out in a tower of approximately 14 meters. In this structure, which

has a cabin similar to that of real helicopters (blajot, MI17, UH) and simulates the

distance of an aircraft over the ground, fast rope maneuvers are performed, used when

there is a high value target on a flat terrain, with the structure of the tower seeks to

optimize the effectiveness of the troops destined in the fight against illegal armed

groups or to capture and hold key positions. It is not trained with aircraft, to avoid

accidents and reduce costs. In a real assault operation, they descend to more than 60

meters (Aviación Ejército Nacional de Colombia, 2012).

The practice of aerial assault has had a great reception within the Colombian armed

forces due to the fact that its results in the field have proven to be quite effective. In

the training of personnel assigned to military aerial assault operations, the need to

create an element that avoids accidents due to slipping or falling into the void or

contingencies presented to the first man descending from a helicopter, who faces risks

such as loosening the descent rope or brake, knots, and tangles in the material, is

recognized. The first man is the one who is most exposed to the dangers of the descent

because he does not have someone to provide the safety protocol at the end of the rope.

The project focuses on designing a braking device adapted to the certified pelvic chair,

which can provide greater safety to users of assault teams, equipment with a

combination of strength and lightness and thus contribute to improving the

development of operations, as is the project called "Modified pelvic chair with brake

support device for descent".

The brake device proposed for the pelvic chair is a second additional friction point that

goes at the height of the leg (right or left depending on the laterality of the descender),

which allows to give an orientation and notion of the rope position. Likewise, friction

device number two prevents knots from being tied because it is a control point through

which the rope passes. In addition, the vital function in case of rope release is to have

a fixed point to place the hand and recover or pick up the rope again, avoiding a free

fall over the area of operations. Article 348 of the Substantive Labor and Social

Security Code, which was modified by Article 10 of Decree 13 of 1967, stipulates and

regulates the hygiene and safety measures that companies must adopt in different

areas of the work environment (Ministry of Labor).

Modification of pelvic chair with brake support device for descent in personnel of the Colombian national army

Vol 4 - No 1 January - June e-ISSN 2745-1194 Pages 21- 29

This design seeks to reduce the risks of accidents and provide the user with greater

flexibility, adapting the pelvic chair to create a safer and more effective system even in

more demanding situations. This braking device is based on the adaptation of a

carabiner to the pelvic chair at a strategic point, allowing control of the rope. It should

be emphasized that the main function is to allow a higher survival rate of the first man

to descend from a helicopter into a military operations area.

Article 22 of the Universal Declaration of Human Rights (United Nations, 1948) refers

to "everyone, as a member of society, has the right to social security and is entitled to

realization, through national effort and international cooperation and in accordance

with the organization and resources of each State, of the economic, social and cultural

rights indispensable for his dignity and the free development of his personality".

Materials and methods

According to Cruz, et. al, (2020). The use of artificial intelligence tools minimizes the

errors in the research data.

The methodological development of the project "Modified pelvic chair with brake

support device for descent" will take into account the scope of both the project and the

product. (Project Management Institute , 2012) It states:

● Project Scope: All the processes and necessary work that the research team must do

to provide the product (Modified Pelvic Chair) with the required features and

functions.

● Product scope: This refers to the features and functionality that the product

generated by the project shall have. This scope will have to include all the requirements

that were gathered through the stakeholders, as long as it is directly related to the need

for which the project was undertaken and to the strategic objectives of the project.

For a clearer perception, the Work Breakdown Structure (WBS) tool will be used,

which allows a hierarchical decomposition of the total scope of work, as well as

creating a frame of reference with respect to the sub-deliverables to be delivered.

The scope of the project carries with it the scope of the product (Pelvic Chair with

Modified Brake Support Device). The product scope based on the presented WBS had

4 phases:

● Phase 1: Prototype Design.

● Phase 2: Prototype Construction

● Phase 3: Laboratory Testing

● Phase 4: Redesign and Final Construction

Modification of pelvic chair with brake support device for descent in personnel of the Colombian national army

Vol 4 - No 1 January - June e-ISSN 2745-1194 Pages 21- 29

Results

The "Prototype Design" phase consists of 3 work packages. The first, "CAD Design", is

the realization of a virtual prototype of the pelvic chair, in a design program such as

AutoCAD, SolidWorks or 3D Max. This will detail the shape, location, characteristics,

size, etc., of the brake support device.

Once the CAD (Computer Aided Design) design was completed, the second work

package, "Dynamic and Static Analysis", was started. This work package is very

important for the development of the pelvic chair, since it allows estimating the

behavior under specific operating conditions.

While the CAD design phase of the prototype was being carried out, the work packages

"analysis and selection of textile material" and "analysis and selection of carabiners"

were developed in order to manufacture the first prototype for testing.

For the analysis and selection of textile material, we searched for standards related to

the physical properties of the material, based on this we will analyze which of these is

the most appropriate for the pelvic chair brake support device, which will be selected

for use in the project product.

For the analysis and selection of carabiners different types of carabiners are analyzed,

thanks to the CAD design and the dynamic and static analysis it will be possible to

calculate the different loads to which the carabiners may be exposed, thus calculating

the resistance that the carabiners should have, material and thickness.

Through resolution 3673 of 2008, the Ministry of Social Protection established the

technical regulations for work at heights, a document that at the time became a

fundamental pillar for regulating work at heights (SURA, 2008).

It was planned to perform different types of tests on the prototype. Mechanical tests,

physical tests and functional tests, each of these tests will be performed in a laboratory

with the necessary equipment and the corresponding report will be obtained.

Mechanical tests:

● Tensile strength: this test is performed to measure the resistance that a textile

material has to the applied tensile force, it can be performed directly to the fabric, to

measure what is its maximum tensile strength or to measure the resistance of the

fastening between fabrics (seams), with this validate if the resistance meets the

required needs or if it is necessary to change the type of fabric to be used or type of

seam made.

● Textile fatigue strength: This is a test to determine the strength of the seam

constructions. For this by means of a machine a cyclic tension process is performed

Modification of pelvic chair with brake support device for descent in personnel of the Colombian national army

Vol 4 - No 1 January - June e-ISSN 2745-1194 Pages 21- 29

(the material is tensioned and then untensioned), this in order to analyze after how

many cycles the seam or fabric can fail, break or unravel. This number of cycles may

vary depending on the tensile strength applied in the cycles.

● Static pull test: It is a test very similar to the tensile strength test, where a force is

applied and increases until the moment where the seam or fabric fails. The difference

is that in this test, a static pull is performed (a specified amount of force in an instant

of time). With this, it will be possible to know what is the maximum resistance of the

material before a moment much force applied in a very short instant of time. (For

example, it is possible to calculate if the force with which the product was designed is

necessary to support a person in the descent, if it is entangled any and stops abruptly).

● Tear Strength: This is a test to analyze the force required to perform tearing, either

edge tearing (force required to initiate with tearing of the material) or internal tearing

(force required to continue with tearing). This test is used for material characterization

and subsequent selection. With it we can obtain criteria to know what would be the

durability of the textile.

● Accelerated aging test: The accelerated aging test is an artificial procedure that allows

to establish what will be the useful life of the product. The procedure consists of using

some conditions, but augmented, such as heat, humidity, sunlight, etc. This makes it

possible to increase the aging of the product. This is done by means of an airtight cabin,

where the product is placed for a certain number of hours; each hour of permanence,

according to conditions, is equivalent to a certain number of hours under normal

conditions.

Safety Expert Pilot Test: An expert company in safety at heights will be in charge of

evaluating the performance of the modified pelvic chair under controlled conditions

(first prototype made), which, after having used and analyzed the product, will issue a

concept with comments and recommendations to improve the product. Based on this

and on the results delivered in each of the tests performed (both physical and

mechanical), the next stage of the project, redesign of the product and construction of

a new modified prototype, will begin.

The redesign and construction of the final prototype will consist of three work

packages, the first "product redesign", followed by the "final prototype construction".

For the first package, an engineer will redesign the prototype with each of the

recommendations gathered in each of the tests and with the concept of the certified

height safety expert, this work will be done in a CAD design program, and if possible a

3D sample will be reprinted in ABS plastic.

With this redesign, measurements and new features, we proceed with the second work

package, the construction of the final prototype. It will include the observations

Modification of pelvic chair with brake support device for descent in personnel of the Colombian national army

Vol 4 - No 1 January - June e-ISSN 2745-1194 Pages 21- 29

gathered in each of the tests performed, such as material, type of carabiner, type of

stitching, stitching material, etc.

Conclusions

The project intends, on the one hand, to raise awareness of the military that performs

this type of training, the risks that may occur with the current pelvic chair taking into

account that the brake is given with the maneuverability of the hand whether left-

handed or right-handed, with the design of the prototype we want to reduce this risk

by means of a braking device,

On the other hand, try to detect the real needs that arise in the practice of aerial assault

and be able to evolve through this design for future training of aerial assault.

The modified pelvic chair with brake device adaptation will serve as equipment to

minimize the indicators of deaths due to malfunction of the same in the field of

operation.

The elaborated prototype vs. the conventional pelvic chair will generate more sources

for the force to be used and produced for the different safe works at heights which

originates a better competitiveness with the occupational health sector.

The impact generated by the modified pelvic chair with braking device is obtained

when the prototype is discarded.

References

Cruz, Poveda, Guzman, Barajas, Martinez,

Bustos, (2020). Research, Artificial

Intelligence And Tools For Researchers.

Colombia 2020. Editorial Scientometrics

E Researching Consulting Group SAS

Ministerio de Trabajo. (s.f.). Obtenido de

https://docs.supersalud.gov.co/PortalWe

b/Juridica/Decretos/D0013_67.pdf

Naciones Unidas. (1948). Resolución 217 A (III).

Obtenido de Resolución 217 A (III):

https://www.un.org/es/universal-

declaration-human-rights/

Organización Internacional del Trabajo . (2016).

Convenio sobre el trabajo a tiempo

parcial, 1994 (núm. 175). Obtenido de

Convenio sobre el trabajo a tiempo

parcial, 1994 (núm. 175):

Modification of pelvic chair with brake support device for descent in personnel of the Colombian national army

Vol 4 - No 1 January - June e-ISSN 2745-1194 Pages 21- 29

https://www.ilo.org/global/standards/W

CMS_488770/lang--es/index.htm

Organización Internacional del Trabajo. (1925).

C017 - Convenio sobre la indemnización

por accidentes del trabajo, 1925 (núm.

17). Obtenido de C017 - Convenio sobre

la indemnización por accidentes del

trabajo, 1925 (núm. 17):

https://www.ilo.org/dyn/normlex/es/f?p=

NORMLEXPUB:12100:0::NO::P12100

_ILO_CODE:C017

Project Management Institute . (2012). LA GUÍA

DEL PMBOOK. Obtenido de LA GUÍA

DEL PMBOOK:

https://uacm123.weebly.com/1-

gestioacuten-del-alcance-del-

proyecto.html

SERVICIO NACIONAL DE APRENDIZAJE.

(04 de 06 de 2009). RESOLUCIÓN 1486

DE 2009. Obtenido de RESOLUCIÓN

1486 DE 2009:

https://www.icbf.gov.co/cargues/avance/

docs/resolucion_sena_1486_2009.htm#:

~:text=Que%20el%20numeral%201%20

del,%C3%A9ticos%2C%20culturales%2

0y%20ecol%C3%B3gicos%E2%80%9D

Sistema Único de Información Normativa . (11

de 05 de 2001). DECRETO 873 DE 2001.

Obtenido de DECRETO 873 DE 2001:

http://suin-

juriscol.gov.co/viewDocument.asp?ruta=

Decretos/1182125

Sistema Único de Información Normativa. (14 de

06 de 1967). LEY 23 DE 1967. Obtenido

de http://www.suin-

juriscol.gov.co/viewDocument.asp?ruta=

Leyes/1579006

SURA. (26 de 09 de 2008). Resolución número

3673 de 2008. Obtenido de

https://www.arlsura.com/index.php/com

ponent/content/article?id=1207#:~:text=

Modification of pelvic chair with brake support device for descent in personnel of the Colombian national army

Vol 4 - No 1 January - June e-ISSN 2745-1194 Pages 21- 29

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sterio,de%20la%20econom%C3%ADa

%2C%20que%20desarrollen