Retractable frame of projection screen

The present invention provides a retractable frame of a projection screen, which comprises: a receiving case; a rolling shaft; a rolling device; a first support rod having one end laterally extended with an engaging plate having a plate hole, two opposing sides of the engaging plate respectively having an engaging surface; a second support rod having one end extended with two engaging arms, and each engaging arm having an engaging hole; a combination member connected with the second support rod and the first support rod; a top supporter; and a projection screen. When being unfolded, the top supporter is upwardly pulled till the connection location of the second support rod and the first support rod being approximately a line, so the engaging arms can be tightly abutted against the end portions of the engaging surfaces for achieving the objective of support.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a retractable frame of a projection screen, especially to a retractable frame of a projection screen having advantages of small volume, light weight and low production cost.

2. Description of Related Art

Generally, a projector or OLED TV projects the image signals to a large-dimension display panel or projection screen for obtaining a better video/audio and visual effect. A conventional retractable frame of a projection screen is often installed with a plurality of support rods which are staggeringly arranged, and two support rods at the bottom are respectively provided with a retractable rod; so with the two retractable rods, the support to the projection screen can be reinforced and the unfolding/folding operation can be facilitated.

However, the mentioned retractable frame of the projection screen requires a considerable number of support rods and the two retractable rods to achieve the effect of reinforcing the support to the projection screen, therefore the volume and weight are inevitably increased and the production cost is raised.

As such, a novel retractable frame of a projection screen shall be invented for improving the mentioned shortages.

SUMMARY OF THE INVENTION

One primary objective of the present invention is to provide a retractable frame of a projection screen having advantages of small volume, light weight and low production cost.

For achieving the mentioned objective, the retractable frame of the projection screen comprises: a receiving case having an accommodation space, a first end part and a second end part; a rolling shaft disposed in the receiving case; a rolling device disposed in the receiving case and one end thereof being installed at the first end part and the other end being connected in the rolling shaft; a first support rod having one end connected inside or outside of the receiving case and the other end laterally extended with an engaging plate having a plate hole, wherein two opposing sides of the engaging plate respectively having an engaging surface; a second support rod having one end extended with two engaging arms corresponding to the engaging plate, and each engaging arm having an engaging hole; a combination member passing through the engaging holes and the plate hole and connected with the first support rod and the second support rod; a top supporter allowing the other end of the second support rod to be connected thereon; and a projection screen having its two ends respectively connected on the top supporter and the rolling shaft so as to be rolled on the rolling shaft by the rolling device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention, whereinFIG. 1is a schematic exploded view showing the retractable frame of the projection screen, according to one preferred embodiment of the present invention;FIG. 2is a schematic perspective view showing the retractable frame of the projection screen being in an unfolding state, according to one preferred embodiment of the present invention;FIG. 3is a partially enlarged view showing the combination of the first support rod, the second support rod and the combination member, according to one preferred embodiment of the present invention;FIG. 4is a schematic view showing the retractable frame of the projection screen being in a folding state, according to one preferred embodiment of the present invention; andFIG. 5is a schematic view showing the first support rod being further comprised a spring, according to one preferred embodiment of the present invention.

As shown in figures, the retractable frame of a projection screen provided by the present invention comprises: a receiving case10; a rolling shaft20; a rolling device30; a first support rod40; a second support rod50; a combination member60; a top supporter70; and a projection screen80.

The receiving case10comprises an accommodation space11, a first end part12and a second end part13; when being in a folding state, the receiving case10can accommodate the rolling shaft20, the rolling device30, the first support rod40, the second support rod50, the combination member60, the top supporter70and the projection screen80. The receiving case10is preferably made of a metal material.

The rolling shaft20is disposed in the receiving case10, and made of, for example but not limited to, a metal or plastic material.

The rolling device30is disposed at the other end of the receiving case10, and further comprises a driven device31and a spring32, wherein one end of the driven device31is installed in the first end part12, one end of the spring32is connected on the driven device31while the other end being connected in the rolling shaft20.

The first support rod40is hollow and one of its side wall comprises a slot (figure not shown), for example but not limited to the right side wall, and one end thereof is connected inside or outside of the receiving case10, the other end is laterally extended with an engaging plate41having a plate hole42, wherein two opposing sides of the engaging plate41are respectively formed with an engaging surface43, and the first support rod40is made of, for example but not limited to, a metal material.

The second support rod50is hollow and one of its side wall also comprises a slot (figure not shown), for example but not limited to the right side wall, one end thereof is extended with two engaging arms51corresponding to the engaging plate41, and each engaging arm51is formed with an engaging hole52, wherein the second support rod50is made of, for example but not limited to, a metal material.

The combination member60can pass through the engaging holes52and the plate hole42and is connected with the first support rod40and the second support rod50. Wherein, the combination member60is, for example but not limited to, a screw or rivet; in this embodiment, a rivet is adopted for illustration and shall not be seen as a limitation for the scope of the present invention.

The top supporter70allows the other end of the second support rod50to be connected thereon, and the top supporter70is made of, for example but not limited to, a metal material. Moreover, the top supporter70further comprises a pull ring71.

The projection screen80has its two ends respectively connected on the top supporter70and the rolling shaft20, thereby being able to be rolled on the rolling shaft20by the rolling device30. Wherein the projection screen is a high gain projection screen, which is a conventional art, thus no further illustration is provided.

In addition, the bottom of the receiving case10further comprises a foot stand15capable of rotating to be approximately perpendicular to the receiving case10, so as to support the retractable frame of the projection screen.

As shown inFIG. 2andFIG. 3, when the retractable frame of the projection screen provided by the present invention is desired to be unfolded, the pull ring71is utilized to upwardly pull the top supporter70till the connection location of the second support rod50and the first support rod40being approximately a line, such that the engaging arms51can be tightly abutted against the end portions of the engaging surfaces43. When the retractable frame moves between closed and open positions, the first support rod40and the second support rod50pivot in a common plane.

Moreover, according to the present invention, the retractable frame of the projection screen further comprises a rolling buffer device90having one end sleeved with the other end of the rolling shaft20and the other end connected at the second end part13, wherein, the rolling buffer device is filled with a visco-elastic material (not shown in figures); so with the visco-elastic material, the rotation speed can be reduced thereby lowering the impact force generated while folding.

As shown inFIG. 4, when the retractable frame of the projection screen is desired to be folded, a force is applied to push the engaging plate41, the engaging arms51are released from the end portions of the engaging surfaces43, and the second support rod50is no longer supported, thus the top supporter70can be downwardly pulled by the recovery force provided by the spring32, thereby storing the projection screen80, the top supporter70, the second support rod50, the first support rod40and the combination member60in the accommodation space11. As such, the retractable frame of the projection screen provided by the present invention has advantages of less components, smaller volume, and easier operation, when comparing to the conventional retractable frame of a projection screen.

Referring toFIG. 5, which is a schematic view showing the first support rod being further comprised a spring, according to one preferred embodiment of the present invention. As shown inFIG. 5, the first support rod40further comprises a spring44disposed through the slot having one end connected on the end part of the first support rod40and the other end connected in the second support rod50. As an alternative, the spring44can also be disposed in the second support rod50through the slot, and one end thereof is connected on the end part of the second support rod50and the other end is connected in the first support rod40; or two springs44are provided and disposed in the first support rod40and the second support rod50through the slot respectively, and a connection string53is connected therebetween, wherein the connection string53is, for example but not limited to, a metal string or nylon string. As such, with the elastic force and the recovery force of the spring44, the retractable frame of the projection screen can be folded or unfolded.

As what is disclosed above, it is appreciated to summarized the retractable frame of the projection screen provided by the present invention has the advantages of small volume, light weight, and low production cost, which can obviously improve the shortages of the conventional retractable frame of a projection screen.