Device for opening and closing trunk lid

A device for opening and closing a trunk lid comprises: a trunk lid opening/closing switch operated between an opening mode and a closing mode; a cylinder having one end rotatably fixed to a body panel; a piston dividing a space within the cylinder into a first chamber and a second chamber; a piston rod having one end rotatably fixed to the trunk lid; and a pneumatic section for selectively supplying compressed air into one of the first and second chambers and discharging air in the other one of the first and second chambers, out of the cylinder, according to an operation of the trunk lid opening/closing switch.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a device for opening and closing a trunk 
lid of an automobile, and more particularly to a device for opening and 
closing a trunk lid, which is so structured as to be able to automatically 
open and close a trunk lid depending upon operation of a switch, whereby 
it improves convenience for a driver and enhances the value of an 
automobile. 
2. Description of the Related Art 
A trunk room defined in a rear portion of an automobile is covered by a 
trunk lid. A rear end of a trunk lid hinge member is fixed to a front end 
of the trunk lid in a lengthwise direction of the automobile, and a front 
end of the trunk lid hinge member is pivotally fixed to a package tray 
panel which is positioned behind a rear seat. Adjacent to the front end of 
the trunk lid hinge member, one end of a torsion bar is connected to a 
portion of the trunk lid hinge member, and the other end of the torsion 
bar is fastened to a proper portion of a body panel. The torsion bar 
allows the opening and closing operation for the trunk lid to be smoothly 
performed with a small force. 
A trunk lid latch is fixed to a rear end of the trunk lid in the lengthwise 
direction of the automobile in such a manner that it can be rotated around 
a hinge shaft, and a striker is fastened to a point on the body panel, 
which corresponds to the position of the trunk lid latch. Beside the trunk 
lid latch, a pawl is provided to the trunk lid, and the pawl functions to 
hold engagement between the trunk lid latch and the striker. By pulling a 
trunk lid lever which is provided in a cabin and connected via a wire to 
the pawl or rotating the pawl by using a key in the outside, the 
engagement between the trunk lid latch and the pawl can be released, and 
accordingly, the trunk lid can be manually opened, or closed after being 
used. 
However, in the structure for opening and closing a trunk lid, constructed 
as mentioned above according to the related art, even when the engagement 
state between the trunk lid latch and the striker is released, the trunk 
lid is only maintained in a state that it is popped up, and thereby in 
order to completely open and close the trunk lid, it is further needed to 
manually raise and lower the trunk lid. 
SUMMARY OF THE INVENTION 
Accordingly, the present invention has been made in an effort to solve one 
or more of the above-described problems occurring in the related art, and 
an object of the present invention is to provide a device for opening and 
closing a trunk lid, which is so structured as to be able to automatically 
open and close a trunk lid depending upon operation of a switch, whereby 
it improves convenience for a driver and enhances the value of an 
automobile. 
According to one aspect of the present invention, there is provided a 
device for opening and closing a trunk lid comprising: a trunk lid 
opening/closing switch operated between an opening mode and a closing 
mode; a cylinder having one end rotatably fixed to a body panel; a piston 
dividing a space within the cylinder into a first chamber and a second 
chamber; a piston rod having one end rotatably fixed to the trunk lid; and 
a pneumatic section for selectively supplying compressed air into one of 
the first and second chambers and discharging air in the other one of the 
first and second chambers, out of the cylinder, according to an operation 
of the trunk lid opening/closing switch. 
According to another aspect of the present invention, the pneumatic section 
comprises: a compressed air supplying station communicated with each of 
the first chamber and the second chamber via a pneumatic line; a first 
valve for valving compressed air supplying operation into the first 
chamber or the second chamber; a second valve for discharging air in the 
first chamber or the second chamber, out of the cylinder; and a control 
section for controlling opening and closing of the first valve and the 
second valve, according to the switching operation of the trunk lid 
opening/closing switch. 
According to another aspect of the present invention, the first valve 
comprises a first solenoid valve and a second solenoid valve disposed in 
portions of the pneumatic line, respectively, which are communicated with 
the first chamber and the second chamber; and the second valve comprises a 
third solenoid valve and a fourth solenoid valve installed at wall 
portions of the cylinder, respectively, which define the first chamber and 
the second chamber. 
According to another aspect of the present invention, the control section 
comprises a first relay for opening the first and fourth solenoid valves 
and closing the second and third solenoid valves in the opening mode of 
the trunk lid opening/closing switch and for closing the first and fourth 
solenoid valves and opening the second and third solenoid valves in the 
closing mode of the trunk lid opening/closing switch. 
According to another aspect of the present invention, the device further 
comprises: a compressor connected to the compressed air supplying station 
and operated at the opening mode and the closing mode of the trunk lid 
opening/closing switch; and a sensor for measuring pressure in the 
compressed air supplying station and stopping operation of the compressor 
when the pressure in the compressed air supplying station is larger than a 
predetermined value. 
According to another aspect of the present invention, the trunk lid 
opening/closing switch operates among the opening mode, the closing mode 
and a neutral mode; and the sensor returns the trunk lid opening/closing 
switch into the neutral mode when it stops the operation of the 
compressor. 
According to another aspect of the present invention, the device further 
comprises a clutch connected to the sensor for turning on or off the 
compressor. 
According to another aspect of the present invention, the device includes a 
pair of pistons disposed in the cylinder; a piston rod of a first piston 
is rotatably fixed to the body panel and a piston rod of a second piston 
is rotatably fixed to the trunk lid; and the space within the cylinder is 
divided into first and second chambers defined between both ends of the 
cylinder and each of the pistons, respectively, and into a third chamber 
defined between the pair of pistons. 
According to another aspect of the present invention, in the opening mode 
of the trunk lid opening/closing switch, compressed air is supplied into 
the second chamber and air in the first and third chambers is discharged 
out of the cylinder; and in the closing mode of the trunk lid 
opening/closing switch, compressed air is supplied into the first and 
third chambers and air in the second chamber is discharged out of the 
cylinder. 
According to another aspect of the present invention, a compressed air 
supplying operation and an air discharging operation for the first and 
third chambers are simultaneously carried out. 
According to another aspect of the present invention, the device further 
comprises a fifth solenoid valve for discharging air in the third chamber 
out of the cylinder, and a second relay for controlling an operation of 
the fifth solenoid valve. 
According to another aspect of the present invention, the second relay 
simultaneously controls both operations of the fourth and fifth solenoid 
valves. 
According to still another aspect of the present invention, at least one 
stopper is formed in an inner surface of the cylinder for limiting a 
stroke of the pair of pistons. 
According to yet still another aspect of the present invention, each of the 
first and second relay comprises a solenoid capable of being energized 
according to the switching operation of the trunk lid opening/closing 
switch; and a contact member opened or closed according to an energized 
state and non-energized state of the solenoids. 
By the features of the present invention, it becomes possible to 
automatically fully open and close a trunk lid depending upon a simple 
switching operation, whereby convenience for a driver is improved and the 
value of an automobile is enhanced.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Reference will now be made in greater detail to a preferred embodiment of 
the invention, an example of which is illustrated in the accompanying 
drawings. Wherever possible, the same reference numerals will be used 
throughout the drawings to refer to the same or like parts. 
Referring to FIG. 1, there is illustrated a circuit diagram showing the 
whole construction of a device for opening and closing a trunk lid in 
accordance with an embodiment of the present invention, and FIG. 2 is a 
side view schematically illustrating an operation of the device for 
opening and closing a trunk lid according to the present invention, in a 
trunk lid opening position and a trunk lid closing position. 
A device for opening and closing a trunk lid according to the present 
invention includes a trunk lid opening/closing switch 1, and the trunk lid 
opening/closing switch 1 can be operated among an opening mode, a closing 
mode and a neutral mode. A trunk lid 7 is automatically and completely 
opened at the opening mode of the trunk lid opening/closing switch 1, 
which is automatically and completely closed at the closing mode of the 
trunk lid opening/closing switch 1, and is maintained in a completely 
opened position and a completely closed position at the neutral mode of 
the trunk lid opening/closing switch 1. 
The trunk lid opening/closing switch 1 is connected to a compressor 3, and 
the compressor 3 is connected to a compressed air supplying station 4. The 
compressor 3 operates when the trunk lid opening/closing switch 1 is in 
the opening mode and the closing mode. When being operated, the compressor 
3 compresses air and stores compressed air into the compressed air 
supplying station 4. The compressed air supplying station 4 is equipped 
with a pressure sensor 5, and the pressure sensor 5 measures a pressure in 
the compressed air supplying station 4. When the pressure in the 
compressed air supplying station 4 is larger than a predetermined value, 
the pressure sensor 5 disconnects a clutch 2 which is provided adjacent to 
the compressor 3, to stop the operation of the compressor 3. Accordingly, 
the compressor 3 operates when being connected with the clutch 2, and does 
not operated when being disconnected from the clutch 2. At the time when 
the pressure sensor 5 stops the operation of the compressor 3, the 
pressure sensor 5 simultaneously returns the trunk lid opening/closing 
switch 1 to the neutral mode. 
A cylinder 10 is connected via a pneumatic line 11 to the compressed air 
supplying station 4, and a pair of pistons 6a and 6b are reciprocatingly 
disposed inside the cylinder 10. A space inside the cylinder 10 is divided 
into three chambers by the pair of pistons 6a and 6b. A first chamber 20 
is defined between an upper end wall of the cylinder 10 and a first piston 
6a, a second chamber 22 is defined between the first piston 6a and a 
second piston 6b, and a third chamber 24 is defined between the second 
piston 6b and a lower end wall of the cylinder 10. The pneumatic line 11 
branches off into three sections to communicate the compressed air 
supplying station 4 with the respective chambers 20, 22 and 24. 
A first hinge bracket 14a is fastened to a lower surface of the trunk lid 
7, and a first piston rod 9a of the first piston 6a is fixed to the first 
hinge bracket 14a such that it can be rotated around a first hinge shaft 
15a. A second hinge bracket 14b is fastened to the a body panel 8 below 
the trunk lid 7, and a second piston rod 9b of the second piston 6b is 
fixed to the second hinge bracket 14b such that it can be rotated around a 
second hinge shaft 15b. 
A first solenoid valve A is disposed in a portion of the pneumatic line 11, 
which is connected to the second chamber 22, and a second solenoid valve B 
is disposed in a portion of the pneumatic line 11, which is connected to 
the first chamber 20 and the third chamber 24. The compressed air 
supplying station 4 selectively supplies compressed air into the first and 
third chambers 20 and 24 or into the second chamber 22, when the first 
solenoid valve A and the second solenoid valve B disposed in the course of 
the pneumatic line 11 are opened or closed. A third solenoid valve C is 
installed in a wall portion of the cylinder 10, which defines the second 
chamber 22, and fourth and fifth solenoid valves D and E are respectively 
installed in end wall portions of the cylinder 10, which define the first 
chamber 20 and the third chamber 24, respectively. The first solenoid 
valve A, second solenoid valve B and third solenoid valve C are connected 
to a first relay RELAY1 via wires, and the fourth solenoid valve D and the 
fifth solenoid valve E are connected to a second relay RELAY2 via wires. 
The first and second relays RELAY1 and RELAY2 include solenoids 16a and 16b 
and contact members 18a and 18b, respectively. A first solenoid 16a of the 
first relay RELAY1 is connected to an open position of the trunk lid 
opening/closing switch 1, and a second solenoid 16b of the second relay 
RELAY2 is connected to a closed position of the trunk lid opening/closing 
switch 1. An operating terminal of the trunk lid opening/closing switch 1 
is connected to a battery 12. 
Hereinafter, a procedure for opening or closing the solenoid valves A, B, 
C, D and E as current is applied to the first and second relays RELAY1 and 
RELAY2 by operation of the trunk lid opening/closing switch 1, will be 
explained in detail. In FIG. 1, opened conditions of the solenoid valves 
A, B, C, D and E are illustrated as "OPEN", and closed conditions thereof 
are illustrated as "CLOSE". 
When the trunk lid opening/closing switch 1 is maintained in the opening 
mode, current is applied from the battery 12 to the first solenoid 16a of 
the first relay RELAY1 via the open end of the trunk lid opening/closing 
switch 1, and the contact member 18a of the first relay RELAY1 is detached 
from an open end and contacted with a close end. If the contact member 18a 
of the first relay RELAY1 is switched to the close end, the second 
solenoid valve B and the third solenoid valve C are closed, and the first 
solenoid valve A is opened. While the trunk lid opening/closing switch 1 
is maintained in the opening mode, the contact member 18b of the second 
relay RELAY2 is held in a state that it is switched to an open end 
thereof. In this situation, the fourth solenoid valve D and the fifth 
solenoid valve E are opened. Accordingly, in the opening mode of the trunk 
lid opening/closing switch 1, compressed air is supplied from the 
compressed air supplying station 4 into the second chamber 22 through the 
first solenoid valve A which is opened, and air in the first chamber 20 
and the third chamber 24 is discharged out through the fourth solenoid 
valve D and the fifth solenoid valve E which are opened, respectively. At 
this time, the second solenoid valve B for supplying compressed air to the 
first chamber 20 and the third chamber 24 and the third solenoid valve C 
for communicating with the second chamber 22 with the outside, are held in 
a closed position. Therefore, by a pressure of the compressed air supplied 
into the second chamber 22, the pistons 6a and 6b are biased toward both 
ends of the cylinder 10, respectively, and the piston rods 9a and 9b are 
projected to the outside, whereby the trunk lid 7 is moved toward the 
completely-opened position. If the trunk lid 7 reaches to the 
completely-opened position, since a pressure in the compressed air 
supplying station 4 increases, the pressure sensor 5 stops the operation 
of the compressor 3 and returns the trunk lid opening/closing switch 1 to 
its neutral mode. 
When the trunk lid opening/closing switch 1 is maintained in the closing 
mode, current is applied from the battery 12 to the second solenoid 16b of 
the second relay RELAY2 via the close end of the trunk lid opening/closing 
switch 1, and the contact member 18b of the second relay RELAY2 is 
switched from an open end to a close end. If the contact member 18b of the 
second relay RELAY2 is switched to the close end, the fourth solenoid 
valve D and the fifth solenoid valve E are closed. While the trunk lid 
opening/closing switch 1 is maintained in the closing mode, the contact 
member 18a of the first relay RELAY1 is held in a state that is switched 
to an open end thereof. In this state, the second solenoid valve B and the 
third solenoid valve C are opened, and the first solenoid valve A is 
closed. Accordingly, in the closing mode of the trunk lid opening/closing 
switch 1, compressed air is supplied into the first chamber 20 and the 
third chamber 24 through the second solenoid valve B which is opened, and 
air in the second chamber 22 is discharged out through the third solenoid 
valve C which is opened. At this time, the first solenoid valve A for 
supplying compressed air with the second chamber 22 and the fourth 
solenoid valve D and the fifth solenoid valve E for communicating the 
first chamber 20 and the third chamber 24 with the outside, are held in a 
closed position. Therefore, by pressure of the compressed air supplied 
into the first and third chambers 20 and 24, the pistons 6a and 6b are 
biased toward a center of the cylinder 10, and the piston rods 9a and 9b 
are inserted into the cylinder 10, whereby the trunk lid 7 is moved toward 
the completely-closed position. If the trunk lid 7 reaches to the 
completely-closed position, since a pressure in the compressed air 
supplying station 4 increases, the pressure sensor 5 stops the operation 
of the compressor 3 and returns the trunk lid opening/closing switch 1 
into its neutral mode. 
A pair of stopper members 13a and 13b are disposed in inner surfaces of 
both ends of the cylinder 10, respectively, and a pair of stopper 
projections 13c and 13d are integrally and radially projected from an 
inner surface of a middle portion of the cylinder 10 such that they are 
spaced apart from each other. The pair of stopper members 13a and 13b and 
the pair of stopper projections 13c and 13d functions to limit strokes of 
the pair of pistons 6a and 6b. 
As a result, according to the device for opening and closing a trunk lid, 
of the present invention, it becomes possible to automatically and fully 
open and close a trunk lid depending upon a simple switching operation, 
whereby convenience for a driver is improved and the value of an 
automobile is enhanced. 
In the drawings and specification, there have been disclosed typical 
preferred embodiments of the invention and, although specific terms are 
employed, they are used in a generic and descriptive sense only and not 
for purposes of limitation, the scope of the invention being set forth in 
the following claims. For example, although it is explained in the 
illustrated embodiment that the third chamber 24 are formed in a lower 
ends of the cylinder 10, the second piston 6b is provided in the third 
chamber 24 and the second piston rod 9b is fastened to the body panel 8, 
it is to be readily understood that the second piston 6b and the second 
piston rod 9b can be omitted such that a space inside the cyliner is 
divided into two chambers partitioned by the first piston 6a.