IJARET - Design and Development of an Automotive Vertical Doors Opening System

International Journal of Advanced JOURNAL OF ADVANCED RESEARCH IN
INTERNATIONAL Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (IJARET)
ENGINEERING AND TECHNOLOGY (2012), © IAEME
ISSN 0976 - 6480 (Print)
ISSN 0976 - 6499 (Online)
Volume 3, Issue 2, July-December (2012), pp. 176-186
IJARET
© IAEME: www.iaeme.com/ijaret.asp
Journal Impact Factor (2012): 2.7078 (Calculated by GISI) ©IAEME
www.jifactor.com

DESIGN AND DEVELOPMENT OF AN AUTOMOTIVE VERTICAL
DOORS OPENING SYSTEM (AVDOS)

2 2
A. Elfasakhany1, 2 *, J. A. Alarcón , D. O. S. Montes
1
Department of Mechanical Engineering, Faculty of Engineering, Taif University, Box 888, Al-
Haweiah, Taif, Saudi Arabia
2
Tecnológico de Monterrey, Campus Ciudad Juárez, Av. Tomas Fernandez Campus 8945, Parque
Industrial Bermudez, CP 32470, Ciudad Juarez, Chihuahua, Mexico
* Corresponding author Tel.: +966 (02) 7272020; Fax: +966(02)7274299
E-mail address: ashr12000@yahoo.com

ABSTRACT

Automotive vertical door opening system (AVDOS) refers to car or truck door that opens
upward instead of outward like conventional cars on the road. Compared with conventional doors,
the AVDOS provides easier access to the car in small spaces and, in turn, allows less parking area
for cars. The main focus of this work was to propose a new design for the AVDOS. That design
overcomes some drawbacks of the available vertical door design. It offers access/egress without
the side movement that available design use. It also provides an easier access into a car that is in a
tighter spot. It can also be able to open/close the doors without having to hard push or slam the
doors. It is safer and less cost. In case of a rollover emergency egress may be easier and more
secure than the available design.

Keyword: Vertical doors, Design, Mechanism, Gas spring, Gear, Development.

I- INTRODUCTION

The term vertical doors (or scissor doors) refers to car or truck doors that open upward instead
of outward like conventional cars on the road. The most famous companies that use those types of
doors are the Italian Lamborghini company, which has become these doors with time bearing its
name (Lambo doors) [1-2]. Those types of doors have firstly begun through car Alfa Romeo

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International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –
6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME

Carabo in 1968. The idea came to the designer based on that the driver was suffering from lack of
the possibility to see what behind the car because of wider car design. In order to reverse the car,
the driver needs to open the door and lean his upper body out of the hatch in order to see behind.
That gave the designer the idea of doors to open up [1]. In 1974, when the same designer worked
on a car Lamborghini Countach's successor, the first commercial vehicle made those doors, due to
facing the same problem of poor rear visibility, he designed it using the same idea of doors that
open up. Currently, Lamborghini is keen to design the majority of such doors [1].
The vertical doors offer many advantages compared with the conventional doors. They offer
the possibility of operating the car during door open, in a manner that would be difficult or
impossible in a car with conventional doors. Because the vertical doors stay within the car's track
throughout their range of movement, they are useful when parking in tight spaces. The hinges of
AVDOS can be placed in a similar location to the conventional door, so a convertible version of
the conventional car is possible with the same door style and, in turn, that reduces the dooring
hazard to cyclists. However, there are some drawbacks for using the vertical doors. The door still
impedes access/egress much more than a conventional door. The manufacture cost of the door
hinge can be more than that of a conventional door. It is also important to consider the cost of
repairing the doors if the mechanisms fail in any way [3]. If the height of the parking lot ceiling is
insufficient, the door may come into contact with it when opened. For example, in case of the car
rolling onto its roof, the doors would not be able to open. In the event of a rollover emergency
egress may be more difficult than with conventional doors, if not impossible. In water or in
situations such as the car exploding, this can be very dangerous. The lifting mechanism for the
door could go out, and then the doors would not be able to open at all.
According to the many drawbacks of the available vertical doors, this work aims at proposing
a new design for the AVDOS. The system overcomes some of the short-comings of existing
system by allowing larger access for ingress and egress than the available vertical door system.
The proposed system can be installed simply and not costly. It can also be able to access/egress
the car without having to hard push or slam the doors. The system can efficiently be an alternative
to the existing hinge mechanism. This work is a part of different projects to design and develop
different mechanical systems/machines, see e.g. [4-8].

II- SYSTEM DESIGN

1- Available Design
The available design of the automotive vertical door opening system (AVDOS) is worked
based on that it is initially open outward before opening upward. The outward motion allows the
top edge of the door to clear from the door frame [2]. Accordingly, drivers need to push the door
two times, one horizontal for the outward and then one vertical for the upward opening. The
AVDOS is shown in Fig. 1 and the detailed function is as follows. When inside: you will grab the
door handle of the car. Pushing the door away from you and the door will open 12 - 18 inches like
they do normally in the conventional doors. From there, the door will stop and not open
horizontally any further. Once done, you will now grab the bottom of the door and lift vertically.
The door will then reach a certain point which it will not lift anymore. At this point, the bottom
back portion of the door will be higher than the roof of the vehicle, as shown in Fig. 2.
Accordingly, you will be able to get out of the vehicle. On the other hand, when you outside the

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car: you will grab the door handle of the car and pulling the door towards you; hence the door will
open slightly (12 - 18 inches) then grab the edge of the door and lift vertically. The door will then
reach a pre-determined point at which it will be able to get in. The second movement of the door
(grab the bottom of the door and lift vertically) is difficult and unstable, especially when door is
heavy. This makes the mechanism is inefficient and complicated to use. The design allows
opening the door of 15 degrees outwards and then lifts it upwards for 75 to 90 degrees. Fig. 3
shows the AVDOS assembled in a car.

Fig. 1: Available design of automotive vertical door opening system (AVDOS) for two systems

2- Proposed Design
The main differences between the proposed design and the available one is that available
design requires two movements to open the doors, the first one is horizontal and the second
one is vertical, as discussed early. In some cases, doors are very heavy for the vertical push.
However, the proposed design is based on moving the door upwards with only one small push
using one finger. Generally, the door is mounted using two hinges, where one hinge is mounted
onto the post of the car body and the other hinge is mounted onto a parallel door structure, as
shown in Fig. 4. This allows the hinges to open the door by swinging away from the vehicle,
thereby providing an adequate opening space to get in and out from the vehicle. Hence, our
proposed mechanism is designed based on allowing the automotive door to open without the side
push that available vertical door does. But, the side movement occurs by the swinging path of the
mechanism. The proposed AVDOS, as shown in Fig. 4, consists of three main subsystems,
mechanism structure (hinges), gears, and gas spring. Detailed of each subsystem is discussed in
the coming sections.

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Fig. 2: Overview of vertical door opened

Fig. 3: Available design of AVDOS assembled in car

2.1-Mechanism Design
Mechanism makeup with detailed dimensions, as shown in Fig 5, is designed to allow the
automotive door moving in a bi-directional i.e., in one or diagonal direction. The dimensions are
calculated based on a door weight of about 110 lb (appropriate for a sports car). The hinges were
designed based on the shape of automotive doors. Since automobiles and trucks are essentially
rectangular in shape, the most common method of providing doors is to mount the hinge on a
forward vertical edge of the door, allowing the trailing edge of the door to swing easily. That
gives more advantage for smaller vehicles, which have much smaller exit openings than the
larger vehicles. Hence, such design provides wider opening of the door due to more swinging
doors in this design configuration.

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Mechanism structure (hinges)

Gears

Hinge mounted
Hinge mounted onto the car body
onto the door
structure

Gas spring

Fig. 4: Proposed AVDOS

2.2-Gas Spring
A gas spring is a type of spring that, unlike a typical metal spring, uses a compressed gas,
contained in a cylinder and compressed by a piston, to exert a force. Gas spring is more or less to
be some kind of pneumatic striker. It pushes the door away from the car when being opened and
vice versa in the closed condition.
The gas spring, as a hydropneumatic adjusting element, consists of a pressure tube, a piston
rod with piston and appropriate connection fittings, as shown in Fig. 6. It is filled with
compressed nitrogen, which acts with equal pressure on differently dimensioned cross-sectional
areas of the piston with same pressure in the both sides of piston. This produces a force in the
extension direction. This extension force can be defined as follows.

P × A = P × ( A − a) + F (1)

F = P×a (2)

where A and a are the cross section area of the piston and the piston rod, respectively; P and F are pressure and
force, respectively.

The extremely high pressure of the nitrogen gas inside cylinder is only applied to the net
cross-sectional area of the piston without the piston rod, as shown in Fig. 6, keeping volumetric
changes inside the cylinder small and, in turn, resultant force (F) near constant. This quality
makes gas springs infinitely useful for providing opening and closing force for door, like moving
mechanisms in machines.

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6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July December (2012), © IAEME
July-December

Fig. 5: Detailed d
dimensions of the proposed AVDOS

Nitrogen

P

P

F
Fig. 6: Working principle of gas spring system

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Unlike a typical metal spring, gas springs provide a constant linear force over a defined stroke,
as well as dynamic damping from the integral piston to smooth the action. The absorption or
damping action for gas springs can be in both compression and extension working conditions. In a
compression gas spring, the shock absorption or dampening occurs in the compression direction
by the compressed gas, as shown in Fig 7. In an extension gas spring, the shock absorption or
dampening occurs in the extension direction using oil since oil cannot be compressed, as shown in
Fig 8.
The gas spring locking function is made possible by a special piston-valve system which
creates a leak-proof separation between the two pressure chambers in the gas spring, as shown in
Figs 7-8. With the valve open, this will provide force assist, ensuring user-friendly motion
sequences due to its predefined damping characteristics. When the valve is closed, the gas spring
will lock with a slight bounce in the desired position. When door reach the extreme opening
position, the gas spring will lock rigidly in the compressed state. By small push, the gas spring
extends and the valve in the piston will open automatically and release the lock.
The gas spring system has many advantages. As system components are not expensive, the
costs of systems are quite low (20 USD) [9]. Moreover, as system is very durable, the cost of
repair is significantly lower than that of other systems. Gas spring systems are safer than
electromotive systems because they can work in inflammable environment without causing fire or
explosion (nitrogen is not flammable). Apart from that, overloading in system will only lead to
sliding or cessation of operation. Unlike electromotive components, gas spring components do not
burn or get overheated when overloaded. The operation of gas spring systems does not produce
pollutants. The system is light and powerful, lighter than equivalent pneumatic system. The door
is raised with the help of a gas spring, thus opening requires minimum efforts (3-10 lb force,
depending on application).

Valve

Fig. 7: Gas spring system at compression condition

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The design limitations of the gas spring system are summarized as follows. The gas spring
is filled with high-pressure nitrogen gas. For this reason, it may never be opened, exposed to high
temperatures, mechanically damaged or exposed to forces beyond normal use. Mechanical
damage, corrosion, colors or impurities can damage the sealing part of the gas spring. The gas
spring operates at a temperature between -18 to +60°C. The temperature change affects the output
force up to approximately 5% for every 15°C of temperature change. The oil viscosity will change
as well.

2.3-Gears
Gears are ones of the most important parts of any machine or mechanism. The function of
gears here is to convert the movement into a single bi-directional diagonal movement. The
user only has to push the door in one direction, i.e. vertical push. By such push, the gas spring
will be activated and vertically move the hinge; but we need a slight horizontal movement to clear
the door from the door frame. The gears are used to provide that function, as shown in Fig 9. By
moving the hinge, the gear 2 will rotate and, in turn, the gear 1. Hence, intermediate hinge will tilt
outward from the fixed hinge where fixed hinge is supported in the door frame. The gear type
used is bevel gears, as shown in Fig 10, and the prerequisite calculations and design
considerations are available elsewhere, see e.g., [10-13].

Valve

Fig. 8: Gas spring system at extension condition

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III- TESTING AND VALIDATION

The system is tested using the cad system and results proof that the system is reliable. Not
only are our AVDOS easy to install but it is also easy to operate, basically open your door using
one push. Figs. 9, 11, and 12 show the system tests at different operating positions.

Intermediate
hinge

Gear 1

Gear 2

Part of the
moving hinge
(a) Front View

(b) Side View

Fig. 9: Gas spring system in (a) front and (b) side views showing the bevel gears

184


Fig. 10: Bevel gears

Fig. 11: AVDOS at door closing

Fig. 12: AVDOS at door open

185


IV- CONCLUSIONS

A new design of the automotive vertical door opening system (AVDOS) was proposed. By the
new design, we can overcome some drawbacks of the available design. The proposed design
consists of three main systems, mechanism structure (hinges), gears, and gas spring. The systems
were designed to provide a wider door opening by using more swinging configuration, which
gives more advantage for smaller vehicles since they have much smaller exit openings than the
larger vehicles. Compared the both designs, available one requires two movements to open the
doors (outward and then upwards) and in some cases doors are very heavy for the vertical
push. However, the proposed design is based on moving the door upwards with only one small
push using one finger. Hence, we will be able to open/close the doors without having to hard
push or slam the doors. Not only are our AVDOS easy to operate but it is also more secure and
less cost. Testing and validation of the proposed system at different operating positions is carried
out and results proof that the system is reliable.

REFERENCES

[1] http://allmobilephoneprices.blogspot.com/2012/01/doors-cars.html
[2] http://en.wikipedia.org/wiki/Scissor_doors
[3] http://www.ehow.com/about_5455626_dangers-vertical-doors.html
[4] A. Elfasakhany, E.Y. Rezola, K.B. Quiñones, R.S. Sánc, Design and Development of a
Competitive Low-cost Robot Arm with Four Degrees of Freedom, Modern Mechanical
Engineering 1 (2011) 47-55.
[5] A. Elfasakhany, J. Hernández, J. C. García, M. Reyes, F. Martell, Design and Development
of House-Mobile Security System, Engineering 3 (2011) 1213-1224.
[6] Elfasakhany, A. Arrieta, D. M. Ramírez, F. Rodríguez, Design and Development of an
Autonomous Trash Sorting System, Global Journal of Pure and Applied Sciences and
Technology vol. 01i2 (2011) 56-64.
[7] A. Elfasakhany, J. Marquez, E.Y. Rezola, J. Benitez Design and Development of an
Economic Autonomous Beverage Cans Crusher, International Journal of Mechanical
Engineering and Technology (IJMET) 3 (2012) 107-122.
[8] A. Elfasakhany, Improving Performance and Development of Two-Stage Reciprocating
Compressors, International Journal of Advanced Research in Engineering and Technology
(IJARET) 3 (2012) 119-136.
[9] http://www.amazon.com/Taylor-Products-Replacement-Shocks-
Boxes/dp/B000MUTFRW
[10] N.C. Pandya, Elements of Machine Design. India: Charotar Publishing House. (1981) 713–
735.
[11] M.F. Spotts, T.E. Shoup, Design of Machine Elements. India: PHI Learning Private Limited.
(2010) 399–426. ISBN 978-81-203-1955-4. Seventh edition, Prentice Hall
[12] http://www.explainthatstuff.com/gears.html
[13] http://www.engineersedge.com/gear_menu.shtml

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