More particularly, the present invention relates to a portable screen device having a good stability, wherein fluctuation is prevented by a stabilized support pole coupling body structure.

Background Art For example, an image, which is expanded and projected from a projector such as a projection TV, is displayed on the screen by means of reflection so that it can be visually seen. In this screen, a coating material of good reflection efficiency is coated on the surface such as texture, paper and synthetic resin. It is required that a good projection screen have the following conditions: a projected image must be clearly reflected, the reappearance of color has to be faithful, an image has to be uniform and light at wide areas, adequate directionality has to be provided and the like. In the prior art, the screen is usually attached to the ceiling or wall. This fixed type screen is pulled out for use, if necessary, while the screen is received in the ceiling or wall. This type of the screen, however, has a problem that it must be fixed at a given location since the screen is not portable.

Meanwhile, in order to solve the above problem, a foldable portable screen device has been developed. A representative one may include a screen being simply a projection sheet, or a screen device having a support pole of a tripod shape in which the screen is put on the support pole. This type of the screen or the screen device has

problems that its use is inconvenient, keeping is not easy, portability is low since the support pole is heavy when the screen is hung on the wall or the support pole of the tripod shape and the like.

In addition, there is a problem that the screen may be crumpled or broken due to careless handling if the screen is additionally kept.

In order to overcome this problem, there has been proposed a portable device for lifting a screen using an elastic force by a spring or a gas lifter, wherein a lifting means of a pantograph type is provided in a casing. FIG. 1 shows such a portable device. FIG. 1 is a perspective view schematically illustrating the portable screen device of the pantograph type in the related art.

As shown in FIG. 1, the conventional portable screen device includes a casing 300. A plurality of arms 310,311, 312 are disposed <BR> <BR> on the casing 300 in an"x", i. e. , pantograph type and are hinge- coupled (h). A screen rod 330, wherein the top of a screen 400 is rolled, is disposed at the top of the arms 310,311, 312. In the above, the bottom of the screen 400 is connected to the casing 300.

Meanwhile, a pair of leaf springs 320 are formed on the casing 300.

The leaf springs 320 resiliently support the arm 310 disposed close to the casing 300. Both ends of the gas lifter 350 are hinge-coupled (h) between the pair of the arms 310,311 to produce an extension force, which are disposed upwardly and downwardly.

In the conventional portable screen device constructed above, if the screen rod 330 is upwardly moved from the casing 300, the plurality of the arms 310,311, 312 provided in the pantograph type are rotated at the hinge (h) point by means of the extension force of the gas lifter 350, so that the screen rod 330 is lifted up.

In other words, in the conventional portable screen device, the

plurality of the arms 310,311, 312 provided in the pantograph type by means of the extension force of the gas lifter 350 are extended, so that the screen 400 is used. The conventional portable screen device constructed above, however, has a disadvantage that the screen 400 cannot be smoothly unfolded if the gas pressure of the gas lifter 350 is low. Further, there is a disadvantage that the screen 400 cannot be unfolded to a limited size at a certain location without completely unfolding the screen.

Disclosure of Invention The present invention is conceived to solve the aforementioned problems in the prior art. An object of the present invention is to provide a portable screen device having a good stability, wherein fluctuation is prevented by a stabilized support pole coupling body structure.

In order to accomplish the above object, a portable screen device according to the present invention comprises a case that is opened and shut by a cover ; a rotary axis that is resiliently and rotatably disposed in the case; a screen having the bottom connected to the rotary axis and the top connected to a rod; and a support pole coupling body having the top hinge-coupled to the center of the rod and the bottom hinge-coupled to axis fixing plates, which are fixed to the central bottom of the case, wherein in the support pole coupling body, one end of each of a long left lower support pole, a short right lower support pole, a short left lower support pole and a short rear lower support pole, is hinge-coupled to the axis fixing plates, one end of a left center support pole is hinge-coupled to the other end of the long left lower support pole, one end of a right center support

pole is hinge-coupled to the other end of a long right lower support pole, one end of a short right upper support pole is hinge-coupled to the other end of the left center support pole, one end of a short left upper support pole is hinge-coupled to the other end of the right center support pole, one end of a right face connection pole is hinge- coupled to the other end of the short left lower support pole, the other end of the right face connection pole is hinge-coupled to the center of the right center support pole, one end of a left face connection pole is hinge-coupled to the other end of the short right lower support pole, the other end of the left face connection pole is hinge-coupled to the center of the left center support pole, the connection point of the short left lower support pole and the right face connection pole and the other end of the long right lower support pole are connected by a first spring, and the connection point of the short right lower support pole and the left face connection pole and the other end of the long left lower support pole are connected by a second spring.

The location where the right face connection pole is hinge- coupled to the right center support pole and the location where the left face connection pole is hinge-coupled to the left center support pole, may be symmetric to each other.

The location where the right face connection pole is hinge- coupled to the right center support pole is located between an intersection point of the right center support pole and the left center support pole and the center of the end of the long right lower support pole.

The portable screen device further comprises a top hanger hingeably coupled to the top of the support pole coupling body,

wherein the rod is integrally coupled to the top hanger.

The top hanger hingeably connected to the top of the support pole coupling body comprises a first friction body and a second friction body both of which are located on a reference axis with them facing each other; a compression spring for consistently applying force to the end of an adjustment lever closely adhered to the rear side of the second friction body, wherein the compression spring is disposed around the reference axis and the adjustment lever is hingeably coupled to the top hanger body by means of a lever hinge axis; and a rod fixing body for fixing the rod, wherein the rod fixing body is integrally formed with the top hanger body.

Brief Description of Drawings FIG. 1 is a perspective view schematically illustrating a portable screen device in the related art ; FIG. 2 is a perspective view schematically illustrating a portable screen device according to the present invention; FIG. 3 is a partially dismantled perspective view illustrating a hinge coupling state at the bottom of the portable screen device shown in FIG. 2 ; FIG. 4 is a partially dismantled perspective view illustrating a hinge coupling state at the ends of support poles in the portable screen device shown in FIG. 2; FIG. 5 is a partially dismantled perspective view illustrating a hinge coupling state at a center end of support poles in the portable screen device shown in FIG. 2; FIG. 6 is a rear view shown to explain upper/lower variable states of the screen in the portable screen device shown in FIG. 2,

which shows a state a support pole coupling body is extended; FIG. 7 is a rear view shown to explain an upper/lower variable state of the screen in the portable screen device shown in FIG. 2, which shows a state a support pole coupling body is contracted; and FIG. 8 is a partially dismantled perspective view illustrating a top brake unit, which can be used in the portable screen device shown in FIG. 2.

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

A portable screen device according to the present invention includes a case 100 that is opened and shut by a cover 101, a rotary axis 110 that is resiliently and rotatably disposed in the case 100, a screen 120 having the bottom connected to the rotary axis 110 and the top connected to a rod 121, and a support pole coupling body having the top hinge-coupled to the center of the rod 121 and the bottom hinge-coupled to axis fixing plates 104, which are fixed to the central bottom of the case 100, as shown in FIG. 2.

In the support pole coupling body, one end of each of a long left lower support pole 130, a short right lower support pole 140, a short left lower support pole 150 and a short rear lower support pole, is hinge-coupled to the axis fixing plates 104. One end of a left center support pole 210 is hinge-coupled to the other end of the long left lower support pole 130. One end of a right center support pole 220 is hinge-coupled to the other end of a long right lower support pole 160. One end of a short right upper support pole 240 is hinge- coupled to the other end of the left center support pole 210. One end

of a short left upper support pole 230 is hinge-coupled to the other end of the right center support pole 220. One end of a right face connection pole 170 is hinge-coupled to the other end of the short left lower support pole 150. The other end of the right face connection pole 170 is hinge-coupled to the center of the right center support pole 220. One end of a left face connection pole 180 is hinge-coupled to the other end of the short right lower support pole 140. The other end of the left face connection pole 180 is hinge- coupled to the center of the left center support pole 210. The connection point of the short left lower support pole 150 and the right face connection pole 170 and the other end of the long right lower support pole 160 are connected by a first spring 200. The connection point of the short right lower support pole 140 and the left face connection pole 180 and the other end of the long left lower support pole 130 are connected by a second spring 190.

In other words, in the present invention, a support pole coupling body in which two diamond shapes are connected is used as a body for supporting the screen 120, which is more stable, portable and easy to use even without using the gas lifter. In the above, the case 100 opened and shut by the cover 101, the rotary axis 110 resiliently and rotatably disposed in the case 100, and the screen 120 having the bottom connected to the rotary axis 110 and the top connected to the rod 121, are the same as those in the conventional portable screen device. The case 100 may further include legs 102 for standing upright the case 100. Furthermore, the cover 101 of the case 100 may further include a handle 103 for facilitating portability.

In the present invention, in order to construct the support body for supporting the screen 120 that is more stable and is easy to use,

the support pole coupling body structure is employed. In the support pole coupling body, one end of each of the long left lower support pole 130, the short right lower support pole 140, the short left lower support pole 150 and the short rear lower support pole, is hinge- coupled to the axis fixing plates 104. One end of the left center support pole 210 is hinge-coupled to the other end of the long left lower support pole 130. One end of the right center support pole 220 is hinge-coupled to the other end of the long right lower support pole 160. One end of the short right upper support pole 240 is hinge- coupled to the other end of the left center support pole 210. One end of the short left upper support pole 230 is hinge-coupled to the other end of the right center support pole 220. One end of the right face connection pole 170 is hinge-coupled to the other end of the short left lower support pole 150. The other end of the right face connection pole 170 is hinge-coupled to the center of the right center support pole 220. One end of the left face connection pole 180 is hinge-coupled to the other end of the short right lower support pole 140. The other end of the left face connection pole 180 is hinge- coupled to the center of the left center support pole 210. The connection point of the short left lower support pole 150 and the right face connection pole 170 and the other end of the long right lower support pole 160 are connected by the first spring 200. The connection point of the short right lower support pole 140 and the left face connection pole 180 and the other end of the long left lower support pole 130 are connected by the second spring 190.

In the hinge coupling of one end of each of the long left lower support pole 130, the short right lower support pole 140, the short left lower support pole 150 and the right lower support pole to the

axis fixing plates 104, respective ends of the long left lower support pole 130, the short right lower support pole 140, the short left lower support pole 150 and the long right lower support pole 160 are disposed in a row at the same location around the first pinhole 105 of the axis fixing plates 104 in order of the long left lower support pole 130, the short right lower support pole 140, the short left lower support pole 150 and the long right lower support pole 160, as shown in FIG. 3. Pinholes are formed in the respective ends of the long left lower support pole 130, the short right lower support pole 140, the short left lower support pole 150 and the long right lower support pole 160. Since the first fixing pin 106 is inserted into the first pinhole 105 formed in the axis fixing plates 104, the long left lower support pole 130, the short right lower support pole 140, the short left lower support pole 150 and the long right lower support pole 160 are hinge-coupled to the axis fixing plates 104. Therefore, the bottom of the support pole coupling body is centrally located at one point of the first pinhole 105 of the axis fixing plates 104. Thus, stable unfolding and folding operations can be made because the force applied when the screen 120 varies up and down is located in a straight line.

The hinge coupling of the other end of the long left lower support pole 130 to one end of the left center support pole 210 can be accomplished in such a manner that a second pinhole 132 is formed in long left lower hinge protrusions 131 formed at the end of the long left lower support pole 130, a third pinhole 213 is formed a left center hinge protrusion 212 formed at the end of the left center support pole 210, the left center hinge protrusion 212 is inserted into the long left lower hinge protrusions 131, and a second fixing

pin 133 is inserted into the second pinhole 132 and the third pinhole 213, as shown in FIG. 4.

A hanger 191 of the second spring 190 is coupled to the second fixing pin 133 so that the second spring 190 is fixed thereto. The hinge coupling of the other end of the long right lower support pole 160 to one end of the. right center support pole 220 is accomplished in the same manner as those described with reference to FIG. 4 except for the coupling of the spring. The hinge coupling of one end of the short right upper support pole 240 to the other end of the left center support pole 210 and the hinge coupling one end of the short left upper support pole 230 to the other end of the right center support pole 220 are accomplished in the same manner as those described with reference to FIG. 4 except for the coupling of the spring.

Furthermore, the hinge coupling one end of the right face connection pole 170 to the other end of the short left lower support pole 150 and the hinge coupling one end of the left face connection pole 180 to the other end of the short right lower support pole 140 are accomplished in the same manner as those described with reference to FIG. 4 except for the coupling of the spring.

The hinge coupling of the other end of the left face connection pole 180 to the center of the left center support pole 210 can be accomplished in such a manner that a fourth pinhole 215 is formed in center hinge protrusions 214 formed in the center hinge coupler 211 integrally fixed to the center of the left center support pole 210, a fifth pinhole 181 is formed at the end of the left face connection pole, the end of the left face connection pole 180 is inserted into the center hinge protrusions 214 of the center hinge coupler 211, the fourth pinhole 215 and the fifth pinhole 181 are made coincident to

each other, and the third fixing pin 216 is inserted into the fourth pinhole 215 and the fifth pinhole 181, as shown in FIG. 5. Further, the hinge coupling of the other end of the right face connection pole 170 to the center of the right center support pole 220 can be accomplished in the same manner as the hinge coupling described with reference to FIG. 5.

In addition, in order for the support pole coupling body to maintain its height at a certain height, the connection point of the short left lower support pole 150 and the right face connection pole 170 and the other end of the long right lower support pole 160 are connected by the first spring 200. The connection point of the short right lower support pole 140 and the left face connection pole 180 and the other end of the long left lower support pole 130 are connected by the second spring 190. The first spring 200 and the second spring 190 are disposed in the opposite directions to provide a contraction force against the extension of the spring. This prevents the long left lower support pole 130 and the long right lower support pole 160 from deviating from the center. In other words, by making the end of the long left lower support pole 130 applied with a force in the direction of the short right lower support pole 140 and the end of the long right lower support pole 160 applied with a force in the direction of the short left lower support pole 150, it is possible to prevent the long left lower support pole 130 and the long right lower support pole 160 from being more wide open in a state where the support pole coupling body is extended as shown in FIG. 6, whereby a predetermined height can be stably maintained.

In particular, in order to prevent the spring from being damaged, the first spring 200 and the second spring 190 can be received into

the left face connection pole 180 and the right face connection pole 170, respectively, which have a n shape whose opened portions is upwardly disposed (a shape corresponding to the left face connection pole 180 in FIG. 5) when the portable screen device is completely folded, as shown in FIG. 7. In other words, the first spring 200 is inserted into the right face connection pole 170 and the second spring 190 is inserted into the left face connection pole 180.

Accordingly, a user can maintain the status of the screen 120 in a state where the screen 120 is unfolded to a certain height. As shown in FIG. 6 and FIG. 7, in a state where the screen 120 is lifted up, the angle between the long left lower support pole 130 and the long right lower support pole 160 becomes narrow. If the screen 120 is lowered, the angle between the long left lower support pole 130 and the long right lower support pole 160 becomes wide. The long left lower support pole 130 and the long right lower support pole 160, however, maintain its state at a predetermined location, while maintaining an equilibrium state by means of an interaction of the first spring 200 and the second spring 190, and the left face connection pole 180 and the right face connection pole 170.

The location where the right face connection pole 170 is hinge- coupled to the right center support pole 220 and the location where the left face connection pole 180 is hinge-coupled to the left center support pole 210 may be symmetric to each other. By making these hinge coupling locations symmetric to each other, the long left lower support pole 130 and the long right lower support pole 160 maintain its location at a predetermined location, while maintaining an equilibrium state by means of the interaction of the first spring 200 and the second spring 190, and the left face connection pole 180 and

the right face connection pole 170.

It is preferred that the location where the right face connection pole 170 is hinge-coupled to the right center support pole 220 be located between the intersection point of the right center support pole 220 and the left center support pole 210 and the center of the end of the long right lower support pole 160. By means of the hinge coupling at this location, the long left lower support pole 130 and the long right lower support pole 160 maintain its location at a predetermined location, while maintaining an equilibrium state by means of the interaction of the first spring 200 and the second spring 190, and the left face connection pole 180 and the right face connection pole 170.

A top hanger 250 is hingeably coupled to the top of the support pole coupling body and the rod 121 is integrally coupled to the top hanger 250. Therefore, the support pole coupling body is extended while the screen 120 is unfolded, by means of an operation to lift up the top hanger 250, whereby the screen 120 is fixed at a predetermined height.

In particular, in order for the support pole coupling body to keep a more stable state by maintaining the height at a predetermined height of the screen 120, the top hanger 250 hingeably connected to the top of the support pole coupling body can be disposed. As shown in FIG. 8, the top hanger 250 includes a first friction body 251 and a second friction body 252, which are located on a reference axis 253 with them facing each other; a compression spring 254 for consistently applying a force to the end of an adjustment lever 255 closely adhered to the rear side of the second friction body 252, wherein the adjustment lever is disposed around the reference axis 253 and the

adjustment lever 255 is hingeably coupled to the top hanger 250 body by means of a lever hinge axis 256; and a rod fixing body 257 for fixing the rod 121, wherein the rod fixing body is integrally formed with the top hanger 250 body.

In the above, the first friction body 251 and the second friction body 252 are fixed to the short left upper support pole 230 and the short right upper support pole 240, respectively, which form the top of the support pole coupling body. Accordingly, in unfolding the screen 120 by upwardly moving the top hanger 250, the adjustment lever 255 of the top hanger 250 is pressed toward the rod fixing body 257 so that the second friction body 252 is separated from the first friction body 251 and the short left upper support pole 230 and the short right upper support pole 240 are thus easily changed each other.

If the support pole coupling body is extended to a desired height after the height of the support pole coupling body is changed to a predetermined height, the compression spring 254 disposed at the center of the reference axis 253 presses the second friction body 252 toward the first friction body 251 so that the second friction body 252 and the first friction body 251 are rubbed each other, by releasing the adjustment lever 255. Therefore, the short left upper support pole 230 and the short right upper support pole 240, which are integrally coupled to the first friction body 251 and the second friction body 252, can be fixed so that they do not vary any further.

Industrial Applicability As described above, the present invention has an effect that it can provide a portable screen device having a good stability by preventing fluctuation using a stabilized support pole coupling body

structure.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.