WO2006029500A1

WO2006029500A1 - Screen assembly

Info

Publication number: WO2006029500A1
Application number: PCT/CA2005/001246
Authority: WO
Inventors: Paul Clubbe
Original assignee: Paul Clubbe
Priority date: 2004-09-17
Filing date: 2005-08-12
Publication date: 2006-03-23
Also published as: EP1789844A4; KR20060053875A; AU2005284621A1; US20060080918A1; CN101048698A; CA2579792A1; JP2008513814A; KR100792526B1; EP1789844A1

Abstract

A screen assembly includes first and second frame members, a spring biased roller rotatably mounted in one of the frame members. A screen is fixed at one end to the roller and is fixed at a second end to the other of the frame members. An extendable linkage assembly connects the frame members and includes a first arm hingedly connected to the first frame member, at a point offset from a center thereof, a second arm hingedly connected to the first arm and to the second frame member, proximal a center thereof, a third arm hingedly connected to the first frame member, at a point on an opposing side of center as the first arm and a fourth arm hingedly connected to the third arm and to the second frame member, proximal the center. The linkage assembly also includes a first biasing member connected along the second arm and to the second frame member, on one side of the center and a second biasing member connected along the fourth arm and to the second frame member, at a point on an opposing side of the center. The first and second frame members are positionable between a closed position and an open position.

Description

SCREEN ASSEMBLY

FIELD OF THE INVENTION

[0001] The present invention relates in general to screens for projecting images onto and in particular, the present invention relates to portable screens that are easily opened for projection of images onto and closed for storage or transport.

BACKGROUND OF THE INVENTION

[0002] Screens are widely used in homes and in offices for displaying movies, television programs, computer displays or the like, from projectors. There are many different types of screen assemblies that are commonly used in both homes and in offices for housing such screens. Wall mounted screens are convenient as a wall provides a stable and flat surface on which to mount the screen. Ceiling mounted screens are also convenient as the screen is opened by extending the screen downwardly for use and the screen is closed by retracting the screen into a housing mounted to the ceiling. The ceiling mounted housing provides a convenient storage location that can be hidden from view. Both wall and ceiling mounted housings are inconvenient for movement of the screen to other locations. Such screens are not intended to be portable for movement throughout a house, an office, between offices, etc.

[0003] Portable screen assemblies have found use as portability of screens is useful for changing venues in which the screen is used. One example of such a screen is the large screen on a tripod stand that has commonly been used for projecting, for example, slides from a slide projector. Although these screens found extensive use in the past, such screens are somewhat awkward to carry and to erect.

[0004] One particular portable screen that has been proposed is disclosed in United States Patent No. 6,249,377 to Takamoto et al. This portable screen includes two frame members that are generally parallel. One of the frame members houses a spring-biased roll to which one end of the screen is attached and the screen is wound onto the roll when in the closed position. The other end of the screen is attached to the other frame member and the frame members are separated to open the screen. Support bars extend between the frame members to maintain the screen in the open position. [0005] This screen suffers from some disadvantages, however. In particular, the edges of this screen are not well supported and tend to curl. Therefore the screen does not provide a flat projection surface for viewing. In instances in which it is desirable to only partially open the screen, the tension in the screen is reduced, causing further screen instability and edge curl.

[0006] It is therefore desirable to provide a portable screen assembly with improved screen stability and reduced edge curl.

SUMMARY OF THE INVENTION

[0007] In one aspect of the present invention there is provided a screen assembly that includes a first frame member, a second frame member and a spring biased roller rotatably mounted in one of the first frame member and the second frame member. A screen is fixed at one end to the spring biased roller and is fixed at a second end to an other of the first frame member and the second frame member. An extendable linkage assembly connects the first frame member to the second frame member. The extendable linkage assembly includes a first arm hingedly connected the first frame member, at a point offset from a center thereof, a second arm hingedly connected to the first arm and hingedly connected to the second frame member, proximal a center thereof, a third arm hingedly connected to the first frame member, at a point on an opposing side of center as the first arm and a fourth arm hingedly connected to the third arm and hingedly connected to the second frame member, proximal the center. The extendable linkage assembly also includes a first biasing member connected to the second arm and connected to the second frame member, at a point offset from the center and a second biasing member connected to the fourth arm and connected to the second frame member, at a point on an opposing side of the center as the first biasing member. The first and second frame members are positionable between a closed position in which the first and second frame members are adjacent each other and the screen is rolled on the spring biased roller, and an open position in which the first and second frame members are separated and the screen is at least partially unrolled from the spring biased roller.

[0008] Advantageously, improved stability of the screen is realized through the use of the extendable linkage assembly. Tension is maintained across the screen as the extendable linkage assembly is biased to counter the bias of the spring biased roller. Thus, the spring biased roller is biased to roll the screen and move the frame members into the closed position. The extendable linkage is biased to counter the bias of the spring biased roller and maintain the frame members in an open position. The spring biased roller and the extendable linkage assembly reduce screen edge curling and provide a substantially flat projection surface. Also, the width of the screen that is used can be adjusted as the separation of the two frame members is adjustable and therefore the screen assembly can be used even when the two frame members are not in the fully opened position. Improved screen stability and reduced screen edge curling is realized even when the frame members are not in the fully opened position.

[0009] In one aspect of the present invention, two arms are hingedly connected to each frame member for providing stability.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a perspective view of a screen assembly according to an embodiment of the present invention, the screen assembly shown in an open position;

[0011] Figure 2 is an alternative perspective view of the screen assembly of Figure 1 , the screen assembly shown in the open position;

[0012] Figure 3 is a rear view of the screen assembly of Figure 1 , shown in the open position and in a partially open position in ghost outline.

[0013] Figure 4 is a rear view of the screen assembly of Figure 1 , shown in the partially open position;

[0014] Figure 5 is a rear view of the screen assembly of Figure 1 , shown in the closed position;

[0015] Figure 6 is a perspective view of the screen assembly of Figure 1 , shown in the closed position and with feet of the screen assembly shown in an open position;

[0016] Figure 7 is a perspective view of a portion of the screen assembly of Figure 1 , with the feet shown in a closed position;

[0017] Figure 8 is an exploded view of the a portion of the screen assembly of Figure 1 , including one of the feet;

[0018] Figure 9A is a front elevation view of a portion of the screen assembly of Figure 1 , including one foot in the open position;

[0019] Figure 9B is a front elevation view of the portion of the screen assembly of Figure 9A, with the sides of the foot compressed for moving from the open position to the closed position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Reference is made to the figures to describe a screen assembly according to an embodiment of the present invention. The screen assembly is indicated generally by the numeral 20 in the figures. The screen assembly 20 includes a first frame member 22, a second frame member 24 and a spring biased roller 26 rotatably mounted in one of the first frame member 22 and the second frame member 24. A screen 28 is fixed at one end to the spring biased roller 26 and is fixed at a second end to an other of the first frame member 22 and the second frame member 24. An extendable linkage assembly 30 connects the first frame member 22 to the second frame member 24. The extendable linkage assembly 30 includes a first arm 32 hingedly connected the first frame member 22, at a point offset from a center thereof, a second arm 34 hingedly connected to the first arm 32 and hingedly connected to the second frame member 24, proximal a center thereof, a third arm 36 hingedly connected to the first frame member 22, at a point on an opposing side of center as the first arm 32 and a fourth arm 38 hingedly connected to the third arm 36 and hingedly connected to the second frame member 24, proximal the center. The extendable linkage assembly 30 also includes a first biasing member 40 connected along the second arm 34 and connected to the second frame member 24, at a point offset from the center and a second biasing member 42 connected along the fourth arm 38 and connected to the second frame member 24, at a point on an opposing side of the center as the first biasing member 40. The first and second frame members 22, 24 are positionable between a closed position in which the first and second frame members 22, 24 are adjacent each other and the screen 28 is rolled on the spring biased roller 26, and an open position in which the first and second frame members 22, 24 are separated and the screen 28 is at least partially unrolled from the spring biased roller 26.

[0021] The portable screen assembly 20 will now be further described with reference to the figures. Referring first to Figures 1 and 2, the first and second frame members 22, 24, respectively are made of a suitable material such as aluminum. As shown in the Figures, the first and second frame members 22, 24, respectively, are approximately equivalent in length and both are generally C-shaped in cross-section. The first frame member 22 is suitably sized to contain the spring biased roller 26 including the screen 28 rolled around the spring biased roller 26, within. The second frame member 24 is suitably sized to receive the extendable linkage assembly 30, as will be further described herein, and to mate with the first frame member 22 when in the closed position, as shown in Figures 5 and 6. Clearly, the edges of the C-shaped first frame member 22 are suitable for mating with complementary edges of the C-shaped second frame member 24.

[0022] A first side of the screen 28 is fixed to the second frame member 24 and an opposing second side of the screen 28 is fixed on the spring biased roller 26 in the first frame member 22. To fix the screen to the second frame member 24, the first side of the screen 28 is fixed to a metal bar that in turn is fixed within the second frame member 24. The opposite second side of the screen 28 is fixed to the spring biased roller 26 that is rotatably mounted within the first frame member 22 and is biased to rotate to receive the screen 28 as the screen 28 rolls around the spring biased roller 26.

[0023] The screen 28 is made of a suitable material such as a multi-layer material including, for example a resin layer covering a bead layer formed on a reflective layer. The reflective layer is bonded to a base material such as polyethylene terephthalate (PET). The screen 28 is flexible for rolling onto the spring biased roller 26 and unrolling when separating the frame members 22, 24.

[0024] As shown in Figures 1 to 6, the screen is movable between an open position which is best shown in Figure 1 , and a closed position which is best shown in Figure 6. The extendable linkage assembly 30 (best shown in Figures 2 to 4) connects the first frame member 22 to the second frame member 24 and provides stability for the screen 28. The extendable linkage assembly 30 includes arms that are numbered as the first arm 32, second arm 34, third arm 36 and fourth arm 38, for the purpose of clarity of the present description. A pair of biasing members referred to herein as the first biasing member 40 and the second biasing member 42, also form part of the extendable linkage assembly 30 for providing stability for the screen 28.

[0025] The first arm 32 is hingedly connected to the first frame member 22 at a point proximal the top of first frame member 22. The hinged connection of the first arm 32 to the first frame member 22 is facilitated by a mounting bracket 44 that is fixed to and protrudes inwardly from an interior wall of the C-shaped first frame member 22. As shown, the mounting bracket 44 is closer to the opening of the C-shaped first frame member 22 than the spring biased roller 42 and is located behind the screen 28 when the first and second frame member 22, 24 are in the open position. Clearly the mounting bracket 44 is located so that it does not interfere with the screen 28 or the spring biased roller 42 and is located so as not to interfere when the first and second frame members 22, 24 are moved into the closed position. The end of the first arm 32 is, in turn, hingedly connected to the mounting bracket 44 to allow rotation of the first arm 32 with respect to the first frame member 22.

[0026] The opposite end of the first arm 32 is hingedly connected to an end of the second arm 34 by a hinge pin, to allow rotation of the second arm 34 with respect to the first arm 32. The opposite end of the second arm 34 is, in turn, connected to the second frame member 24 at a point proximal the center of the second frame member 24. The hinged connection of the second arm 34 to the second frame member 24 is facilitated by a mounting bracket 46 that is fixed to the back, within the C-shaped second frame member 24. The second arm 34 is hingedly connected to the mounting bracket 46.

[0027] As shown in the Figures, the first biasing member 40 is a spring coil. One end of the first biasing member 40 is connected along the second arm 34, at a point approximately two thirds of the way along the length of the second arm 34, closer to the point of connection of the second arm 34 to the second frame member 24 than to the point of connection of the second arm 34 to the first arm 32. The other end of the first biasing member 40 is connected to the second frame member 24 at a point proximal but not at the top of the second frame member 24.

[0028] As shown in the figures, the third arm 36 is hingedly connected to the first frame member 22 at a point proximal the bottom of first frame member 22. The hinged connection of the third arm 36 to the first frame member 22 is facilitated by a mounting bracket 48 that is fixed to and protrudes inwardly from an interior wall of the C-shaped first frame member 22. As shown, the mounting bracket 48 is closer to the opening of the C-shaped first frame member 22 than the spring biased roller 42 and is located behind the screen 28 when the first and second frame members 22, 24 are in the open position. Clearly the mounting bracket 48 is located so that it does not interfere with the screen 28 or the spring biased roller 42 and is located so as not to interfere when the first and second frame member 22, 24 are moved into the closed position. The end of the third arm 36 is, in turn, hingedly connected to the mounting bracket 48 to allow rotation of the third arm 36 with respect to the first frame member 22.

[0029] The opposite end of the third arm 36 is hingedly connected to an end of the fourth arm 38 by a hinge pin, to allow rotation of the fourth arm 38 with respect to the third arm 36. The opposite end of the fourth arm 38 is, in turn, connected to the second frame member 24 at a point proximal the center of the second frame member 24. The hinged connection of the fourth arm 38 to the second frame member 24 is facilitated by a mounting bracket 50 that is fixed to the back, within the C-shaped second frame member 24. The mounting bracket 46 to which the second arm 34 is connected, is adjacent the mounting bracket 50 to which the fourth arm 38 is connected. Thus, the point of connection of the second arm 34 to the second frame member 22 is adjacent the point of connection of the fourth arm 38 to the second frame member 22.

[0030] Similar to the first biasing member 40, the second biasing member 42 is also a coil spring. One end of the second biasing member 42 is connected along the fourth arm 38 at a point approximately two thirds of the way along the length of the second arm 24, closer to the point of connection of the fourth arm 38 to the second frame member 24 than to the point of connection of the fourth arm 38 to the third arm 36. The other end of the second biasing member 42 is connected to the second frame member 24 at a point proximal but not at the bottom of the second frame member 24.

[0031] As is shown in the Figures, the third arm 36 is hingedly connected to the first frame member 22 at a point that is approximately equidistant and on an opposing side of center as the first arm 32. Similarly, the second biasing member 42 is connected to the second frame member 24 at a point that is approximately equidistant and on an opposing side of center as the first biasing member 40. Clearly the second arm 34 is not as long as the first arm 32. Similarly, the fourth arm 38 is not as long as the third arm 36.

[0032] When the screen assembly 20 is in the open position, the first frame member 22 is separated from the second frame member 24, as shown in Figure 2. In this position, the point of connection of the first and second arms 32, 34 is adjacent the point of connection of the third and fourth arms 36, 38. Each of the first, second, third and fourth arms 32, 34, 36, 38 are as close to horizontal as these arms are permitted to extend. The spring biased roller 26 is biased to roll up the screen 28 which is fully extended. Thus, the spring biased roller biases the screen assembly into the closed position. The first biasing member 40 biases the second arm 34 upwardly, into the near-horizontal position shown in Figure 2. The second biasing member 42 biases the fourth arm 38 downwardly, into the near-horizontal position shown in Figure 2. Thus, the first and second biasing members 40, 42 bias the screen assembly 20 into the open position. When in the open position, the force biasing the screen assembly 20 into the open position is greater than the force biasing the screen assembly 20 into the closed position. Thus, the screen remains in the open position.

[0033] When the screen assembly 20 is in the closed position, the first frame member 22 is adjacent and co-operates with the second frame member 24, as shown in Figures 5 and 6. The first and second frame members 22, 24 mate together to form an enclosure that contains the screen 28 rolled around the spring biased roller 26 and the extendable linkage assembly. In this position, the first, second, third and fourth arms 32, 34, 36, 38 as well as the first and second biasing members 40, 42 are substantially vertical and are located within the second frame member 24, as best shown in ghost outline in Figure 5.

[0034] The first frame member 22 is positionable with respect to the second frame member 24 such that the screen assembly is in the open position, the closed position, or a partially open position in between the open and closed positions, shown in ghost outline in Figure 3 and in full outline in Figure 4.

[0035] Each of the first frame member 22 and the second frame member 24 includes an upper end cap 53 and a bottom end cap 54 that are fixed to and close off the ends of the respective one of the first frame member 22 and the second frame member 24. Each of the first and second frame members 22, 24 also includes two collapsible stabilizing feet 52 at a bottom end thereof for stabilizing the screen in an upright position. Figure 6 is a perspective view of the screen assembly in the closed position, with the collapsible stabilizing feet 52 shown in an open position. Figure 7 is a perspective view of a portion of the screen assembly showing the collapsible stabilizing feet 52 (referred to as feet herein) in a closed position. Referring to Figures 6 and 7, the second frame member 24 includes the bottom end cap 54 that wraps around the lower portion of the second frame member 24 and is closed on a bottom surface thereof. The bottom end cap 54 is fixed to the second frame member 24 and includes two generally rectangular recessed receptacles 56 for receiving the feet 52 therein, when the feet 52 are in the closed position. The recessed receptacles 56 are on opposing sides of the bottom end cap 54, such that the feet 52 are received in the receptacles 56 in a front and a rear of the second frame member 22.

[0036] Referring to Figures 8, 9A and 9B to describe one side of the first frame member 22, the bottom end cap 54 includes a semi-circular slot 58 at a bottom end of the rectangular recessed receptacle 56, for receiving a portion of one of the feet 52. Downwardly projecting parallel walls 60 extend only partially into the semicircular slot 58, as shown. At each end of the semicircular slot, apertures 62 extend through the bottom end cap 54 for receiving pivot pins of one of the feet 52.

[0037] Each of the feet 52 has a generally U-shaped body 64 with a pair of semi-circular projections 66 at each end of the body 64. Each semi-circular projection 66 includes one flat surface 68 facing inwardly and a shaped surface 70 facing outwardly. Each shaped surface 70 includes a rib 72 that is defined by a forward inclined edge 74 and a rearward shoulder 76.

[0038] Pivot pins 78 extend outwardly from each of the shaped surfaces 70 of the two outermost semi-circular projections 66, approximately from the center of each semi-circular projection 66 of each foot. The pivot pins 78 are received in the apertures 62 of the bottom end cap 54 for hinged connection of each foot 52 in the bottom end cap 54. Clearly the semicircular projections 66 extend into the semi-circular slot 58 and the shaped surfaces 70 cooperate with the walls 60 for positioning the foot 52 in an open position and a closed position.

[0039] When the foot 52 is in the closed position, the body 64 of the foot 52 is received in the respective recessed receptacle 56. One edge of each of the walls 60 abuts a respective forward inclined edge 75 of the shaped surface 70. When moving the foot 52 from the closed position to the open position, each inclined edge 75 is forced against the edge of the respective wall 60 to move the side of the rib 72 into abutment with and adjacent the respective wall 60. It will be understood that this movement in each of the semicircular projections 66, and the interaction with the walls 60, causes the ends of the U-shaped body 64 to be urged together. When the foot 62 is moved all the way to the open position, each rib 72 is moved past the respective wall 60 and the rearward shoulder 76 abuts the edge of the wall 60. In this position, the ends of the U-shaped body 64 are no longer urged together and therefore they are returned to the separated position, as best shown in Figure 9A. When in the open position, each foot 52 extends outwardly from the bottom end cap 54 to stabilize the remainder of the screen assembly 20 in the upright position. To return the foot 62 to the closed position, the ends of the U-shaped body 64 are urged together as best shown in Figure 9B, and the foot 62 is moved to the closed position.

[0040] It will be understood that two feet 52 are hingedly connected on opposite sides of each bottom end cap 54. The two feet 52 extend outwardly from opposite sides of each bottom end cap 54. Thus, the screen assembly 20 of the present embodiment includes four feet 52 in total. [0041] Referring to Figures 1 and 2, the screen assembly 20 includes releasable locking mechanisms on each side thereof, to maintain the screen assembly 20 in the closed position during, for example, transporting. Each releasable locking mechanism includes a spring biased latch 80 on the first frame member 22 that cooperates with a respective catch 82 on the second frame member 24. The spring biased latch 80 is received in the catch 82 and is retained therein until the spring biased latch 80 is urged inwardly toward the first frame member 22, to release the latch 80 from the catch 82. As shown in Figure 6, each latch 80 is located approximately central to a respective side of the first frame member 22. Similarly, each catch 82 is located approximately central to a respective side of the second frame member 24 such that each latch 80 is received in the respective catch 82 when the screen assembly 20 is in the closed position.

[0042] For ease of portability, the screen assembly 20 also includes a handle 84 fixed at either end, to the second frame member 24. The handle 84 is approximately centrally located along an end surface of the second frame member 24.

[0043] In use, the screen assembly 20 is set up by moving each of the feet to the open position as shown in Figure 6. Next, each latch 80 is released from the respective catch 82 by urging each latch 80 inwardly toward the first frame member 22. With the latches 80 released from the catches 82, the first and second frame members 22, 24 are separated, thereby unrolling the screen 28 in between. For transportation, the first and second frame members 22, 24 are moved toward each other until each latch 80 is received in the respective catch 82. When moving the first and second frame members 22, 24 together, the screen 28 is rolled on the spring biased roller 26. The feet 52 are then moved into the closed position by urging the ends of the U-shaped body 64 together, thereby releasing the rearward shoulders 76 from abutment with the edges of the respective walls 60. The feet 52 are then pivoted into the respective recessed receptacles 56.

[0044] A specific embodiment of the present invention has been shown and described herein. However, modifications and variations to these embodiments may be possible. For example, the size and shape of many of the elements described herein may vary while still performing the same function. All such modifications and variations are believed to be within the sphere and scope of the present invention.

Claims

CLAIMSWhat is claimed is:

1. A screen assembly comprising: a first frame member; a second frame member; a spring biased roller rotatably mounted in one of said first frame member and said second frame member; a screen being fixed at one end to said spring biased roller and being fixed at a second end to an other of said first frame member and said second frame member; an extendable linkage assembly connecting said first frame member to said second frame member, the extendable linkage assembly comprising: a first arm hingedly connected said first frame member, at a point offset from a center thereof; a second arm hingedly connected to said first arm and hingedly connected to said second frame member; a third arm hingedly connected to said first frame member, at a point on an opposing side of center as said first arm; a fourth arm hingedly connected to said third arm and hingedly connected to said second frame member; a first biasing member connected along said second arm and connected to said second frame member; a second biasing member connected along said fourth arm and connected to said second frame member; said first and second frame members being positionable between a closed position in which said first and second frame members are adjacent each other and said screen is rolled on said spring biased roller, and an open position in which said first and second frame members are separated and said screen is at least partially unrolled from said spring biased roller.

2. The screen assembly according to claim 1 , wherein said second arm is hingedly connected to said second frame member proximal a center of said second frame member.

3. The screen assembly according to claim 2, wherein said fourth arm is hingedly connected to said second frame member proximal said center of said second frame member.

4. The screen assembly according to claim 1 , wherein said first biasing member is connected to said second frame member at a point offset from said center and said second biasing member is connected said second frame member at a point on an opposing side of said center as said first biasing member.

5. The screen assembly according to claim 1 , wherein said first arm is longer than said second arm.

6. The screen assembly according to claim 2, wherein said third arm is longer than said fourth arm.

7. The screen assembly according to claim 1 , wherein said point at which said first arm is hingedly connected to said first frame member is proximal an end of said first frame member.

8. The screen assembly according to claim 7, wherein said point at which said third arm is hingedly connected to said first frame member is proximal an opposing end of said first frame member.

9. The screen assembly according to claim 1 , wherein when said first and second frame members are in a fully open position, a point of hinged connection of said first and second arms is adjacent a point of hinged connection of said third and fourth arms.

10. The screen assembly according to claim 1 , wherein said first biasing member is connected to said second arm at a point along said second arm that is closer to said second frame member than a center of said second arm.

11. The screen assembly according to claim 10, wherein said second biasing member is connected to said fourth arm at a point along said fourth arm that is closer to said second frame member than a center of said fourth arm.

12. The screen assembly according to claim 1 , further comprising stabilizing feet, each frame member having at least one stabilizing foot at an end thereof for stabilizing said screen in an upright position when said first and second frame members are in an open position.

13. The screen assembly according to claim 1 , further comprising a releasable locking mechanism on said frame members for releasably locking said first frame member to said second frame member when said frame members are in said closed position.

14. A screen assembly comprising: a first frame member; a second frame member; a spring biased roller rotatably mounted in one of said first frame member and said second frame member; a screen being fixed at one end to said spring biased roller and being fixed at a second end to an other of said first frame member and said second frame member; an extendable linkage assembly connecting said first frame member to said second frame member, the extendable linkage assembly comprising: a first arm hingedly connected said first frame member, at a point offset from a center thereof; a second arm hingedly connected to said first arm and hingedly connected to said second frame member, proximal a center of said second frame member; a third arm hingedly connected to said first frame member, at a point on an opposing side of center as said first arm; a fourth arm hingedly connected to said third arm and hingedly connected to said second frame member, proximal said center of said second frame member; a first biasing member connected along said second arm and connected to said second frame member, at a point offset from said center of said second frame member; a second biasing member connected along said fourth arm and connected to said second frame member, at a point on an opposing side of said center of said second frame member as said first biasing member; said first and second frame members being positionable between a closed position in which said first and second frame members are adjacent each other and said screen is rolled on said spring biased roller, and an open position in which said first and second frame members are separated and said screen is at least partially unrolled from said spring biased roller.