TWI395050B - Projection screen apparatus - Google Patents

Description

Projection screen device

The present invention relates to a projection screen apparatus, and more particularly to a projection screen apparatus having a speed reduction mechanism.

At present, projection screens have been widely used in homes, schools and commercial fields, such as home theater, multimedia teaching, command centers, video conference rooms and many other occasions.

The more conventional hand-held projection screen device is composed of a tie rod, a curtain, a torsion spring, a rotating tube and an outer casing, and is assembled on the top of a bracket. Pulling the pull rod pulls the curtain to open the curtain, and the tube will rotate with it. The torsion spring will deform and accumulate a certain elastic force, and then the tab on the rod will be stuck on the hook at the bottom end of the bracket to Positioning. However, when the curtain is positioned, the elastic force of the torsion spring will be applied to the rotating tube, and the rotating tube will have a certain turning tendency, which will cause the curtain to be stressed. Under the long-term tension, the curtain fiber will be deformed, such as The formation of wrinkles on the strip not only affects the flatness of the curtain, but also reduces the service life of the curtain. Furthermore, when it is desired to close the curtain, the fitting relationship between the tab and the hook must be released before the lever can be released, and the elastic force of the torsion spring is used to rotate the tube in the opposite direction (ie, to rotate), so that the curtain roll Wrap around the tube. However, the conventional hand-drawing projection screen does not have any deceleration device, and only relies on the rewinding force to raise the curtain. Because the rewinding force is large, the speed of the rewinding of the curtain is quite fast, and the curtain is about to be When fully retracted, the speed of the curtain rewinding will not slow down, thus causing the tie rod to hit the outer casing, causing damage to the tie rod or the outer casing or even other components.

In order to avoid the defects of the above-mentioned conventional structure, the Chinese Patent Publication No. CN 2840111Y discloses a projection screen deceleration positioning mechanism which is disposed in the rotary tube and is composed of a transmission mechanism, a reduction mechanism and a positioning mechanism. . The transmission mechanism includes three sets of planetary gears, and the speed reduction mechanism is connected with the transmission mechanism, and is composed of a brake fixing frame and a centrifugal brake shoe disposed on the fixing frame, and the positioning mechanism is a ratchet positioning device. Cloth curtain When positioning is required during the pull-down process, the transmission mechanism (ie, the planetary gear system) stops moving, and the stop boss on the centrifugal brake shoe is caught in the teeth of the stop ratchet to achieve the positioning effect of the curtain. When it is necessary to rewind the curtain, it is necessary to pull the curtain downward for a distance, so that the stopping boss is disengaged from the binding ratchet, and then the external force is removed, and the rotating tube is rotated by the torsion spring and driven. The planetary gear system accelerates, the centrifugal brake shoe expands under the action of accelerating centrifugal force, and friction is generated by friction with a brake drum to reduce the rotation speed of the rotary tube, so that the curtain is slowly rewinded.

Because the above-mentioned projection screen deceleration positioning mechanism uses the centrifugal brake shoe and the ratchet positioning device as the speed reduction mechanism and the positioning mechanism respectively, when the pipe is rewinded, a large rewinding force is required to make the stop cam on the centrifugal brake shoe. The stage is disengaged from the stop ratchet, which in turn allows the tube to be reset, but the large rewinding force acts on the curtain for a long time, which will affect the quality of the curtain (such as flatness). During the deceleration and positioning process of the conventional projection screen deceleration positioning mechanism, the centrifugal brake shoe and the ratchet positioning device generate relatively large noise, and sometimes it is necessary to repeatedly receive and release to make the stop boss snap in or out. The ratchet is extremely inconvenient to operate and is not suitable for use in modern office applications.

Moreover, since the above-mentioned projection screen deceleration positioning mechanism adopts a planetary gear system as its transmission mechanism, and the centrifugal brake shoe and the ratchet positioning device respectively reduce the speed reduction mechanism and the positioning mechanism, the overall structure comparison of the conventional projection screen deceleration positioning mechanism is Complex and needs to be improved.

An object of an embodiment of the present invention is to provide a projection screen device provided with a speed reduction mechanism capable of controlling the rewinding speed of the projection screen to be smoothly recovered, thereby maintaining the quality of the projection screen and the structural stability of the projection screen device.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein.

In order to achieve one or a part or all of the above, an embodiment of the present invention provides a projection screen The device comprises: a projection screen, a retracting mechanism, a power mechanism, a self-locking mechanism and a speed reducing mechanism. The retractable mechanism is coupled to the projection screen, selectively rotatable in the first direction to release the projection screen, and selectively rotatable in a second direction opposite the first direction to recover the projection screen. The power mechanism is coupled to the retractable mechanism for providing a regenerative power to the retracting mechanism to enable the retracting mechanism to rotate in the second direction to recover the projection screen. The speed reduction mechanism includes a fixed shaft and a loop-shaped reduction coil. The fixed shaft is connected to the retracting mechanism and is selectively rotatable in the first or second direction according to the rotation of the retracting mechanism, and the deceleration coil is sleeved on the fixed shaft and formed between the outer surface of the fixed shaft A gap. The deceleration coil is arranged such that when the fixed shaft rotates in the first direction, the gap between the deceleration coil and the fixed shaft becomes larger, so that the fixed shaft can freely rotate with the retracting mechanism, and when the fixed shaft rotates in the second direction When the gap between the reduction coil and the fixed shaft is contracted by the deformation of the reduction coil, the reduction coil is tightened on the outer surface of the fixed shaft, and a frictional force is generated between the reduction coil and the fixed shaft, which causes a deceleration effect on the fixed shaft. To control the recycling speed of the projection screen.

According to an embodiment of the invention, the speed reduction mechanism further includes a clutch fixedly coupled to the self-locking mechanism, the deceleration coil being selectively connectable to the clutch, and when the clutch is rotated in the first direction, the deceleration coil is disengaged from the clutch, The clutch is rotated, and when the clutch is rotated in the second direction, the reduction coil is engaged with the clutch to be rotated.

According to an embodiment of the invention, one end of the deceleration coil abuts against one side surface of the clutch, and the side surface of the clutch is provided with a plurality of clutch teeth. When the clutch rotates in the first direction, the deceleration coil One end is disengaged from the clutch teeth of the clutch, and when the clutch is rotated in the second direction, one end of the deceleration coil is engaged with one of the clutch teeth of the clutch.

According to an embodiment of the invention, the projection screen apparatus further includes a self-locking mechanism coupled to the retracting mechanism, and the deceleration coil is coupled to the self-locking mechanism for indirect connection to the retracting mechanism.

According to an embodiment of the invention, the self-locking mechanism comprises: a self-locking shaft fixed to the movement The force generating portion is a self-locking core which is cylindrical and fixed on the self-locking shaft and has a cylindrical outer surface on which at least one inner ball track is disposed. The inner ball track has a self-locking point: a self-locking a jacket rotatably sleeved on the self-locking core and connected to the receiving mechanism, the self-locking jacket having a cylindrical inner side surface opposite to the outer side surface of the self-locking core and provided with at least one The outer ball track, corresponding to the inner ball track of the self-locking core: and at least one ball disposed between the self-locking core and the self-locking jacket, and movable in the inner ball track and the outer ball track.

According to an embodiment of the invention, the deceleration coil of the speed reduction mechanism and the clutch are located outside the self-locking jacket, and the clutch is fixed to an end surface of the self-locking jacket of the self-locking mechanism.

According to an embodiment of the present invention, the end of the deceleration coil may also be rotatably coupled to the retracting mechanism in the first direction with the retracting mechanism, and the deceleration spring when the end of the deceleration coil rotates in the first direction The friction between the fixed shaft and the fixed shaft is reduced.

According to an embodiment of the invention, the retracting mechanism includes a rotatable diverter coupled to the projection screen and selectively rotatable in a first direction or a second direction for releasing or retrieving the projection screen.

According to an embodiment of the invention, the power generating portion of the power mechanism includes a torsion spring and a support shaft, and the connecting seat is rotatably mounted on one of the shaft ends of the support shaft, and the connecting seat is fixed on the rotating tube to be The rotary tube is rotated, and the torsion spring is disposed between the support shaft and the connecting seat.

According to an embodiment of the invention, the end of the reduction coil is connected to the retracting mechanism through the connection seat of the power mechanism, and the fixed shaft of the reduction mechanism is coupled to the support shaft.

According to an embodiment of the invention, the torsion spring is a coil spring sleeved on the support shaft and has a first pin fixed to the support shaft: and a second pin fixed to the connection base.

According to an embodiment of the present invention, there is further provided a self-locking mechanism, one of the deceleration coils The end is connected to the retracting mechanism through a self-locking mechanism.

According to an embodiment of the invention, the self-locking mechanism comprises: a self-locking shaft fixed to the power generating portion; a self-locking core having a cylindrical shape fixed on the self-locking shaft and having a cylindrical outer surface on which Providing at least one inner ball track, the inner ball track has a self-locking point; a self-locking outer sleeve rotatably sleeved on the self-locking core and connected with the retracting mechanism, the self-locking outer casing has a cylindrical inner side surface Opposite the outer surface of the self-locking core, and provided with at least one outer ball track corresponding to the inner ball track of the self-locking core; and at least one ball disposed between the self-locking core and the self-locking jacket, and capable of being The ball track moves in the outer ball track.

According to an embodiment of the invention, one end of the reduction coil of the speed reduction mechanism is coupled to the self-locking jacket, and the self-locking shaft of the self-locking mechanism is coupled to the fixed shaft of the speed reduction mechanism.

According to an embodiment of the invention, the deceleration coil of the speed reduction mechanism is housed in the self-locking jacket, and one end of the deceleration coil extends to the outside of the self-locking jacket and is fixed to one end surface of the self-locking jacket.

According to an embodiment of the present invention, a fixing post is disposed on one end surface of the self-locking jacket, and a buckle is disposed on one end of the deceleration coil, and the buckle is sleeved on the fixing post.

Compared with the prior art of the present invention, the speed reduction mechanism of the projection screen device according to an embodiment of the present invention includes a reduction coil that is sleeved on a fixed shaft, and the reduction coil is rotatably connected directly or indirectly to one. Retractable and retractable mechanism of the projection screen. When the projection screen is pulled down through the retracting mechanism, the deceleration coil is in a relaxed state, and the gap between the deceleration coil and the fixed shaft is large, which does not cause a deceleration effect on the retracting mechanism or the projection screen. When the projection screen is recovered, the reduction coil is rotated by the retracting mechanism, causing the deceleration coil to be deformed and tightened on the fixed shaft, so that the gap between the deceleration coil and the fixed shaft becomes smaller, and friction is generated on the fixed shaft. The greater the rotational speed, the greater the friction between the deceleration coil and the fixed shaft, which can provide a deceleration effect on the retracting mechanism or the projection screen to adjust the recovery speed of the projection screen. The projection screen in an embodiment of the present invention can be slowly recovered at a constant speed, thereby avoiding collision caused by instantaneous recovery in the conventional structure. Hit the destruction.

The following description of the various embodiments is provided to illustrate the specific embodiments of the invention. The directional terms mentioned in the present invention, such as "upper", "lower", "before", "after", "left", "right", etc., are merely directions referring to the additional drawings. Therefore, the directional terms used in the following examples of the invention are intended to illustrate the invention and not to limit the invention.

Referring to the projection screen device 100 of the embodiment of the present invention shown in FIG. 1 to FIG. 11 , the projection screen device 100 of the present embodiment includes: a projection screen 1 , a retracting mechanism 2 , and a power mechanism. 3. A self-locking mechanism 4, a speed reduction mechanism 5, a casing 6, a first end cover 7 and a second end cover 8. The outer casing 6 is fixed and has a slender cylindrical structure for receiving and shielding the retracting mechanism 2, the power mechanism 3, the self-locking mechanism 4 and the speed reducing mechanism 5. The projection screen 1 can also be recovered in the outer casing 6, or The outer casing 6 projects outwardly to the desired location for the image to be projected onto it. Both ends of the outer casing 6 are sealed by the first and second end covers 7, 8 to prevent foreign objects from entering, thereby ensuring that the projection screen apparatus 100 can work normally in a safe and stable working environment.

Referring to FIG. 2 to FIG. 4 , the retracting mechanism 2 of the projection screen device 100 is connected to the projection screen 1 and can be rotated along a first direction (eg, clockwise direction) so that the projection screen 1 is self-contained. The outer casing 6 projects outwardly: or rotates in a second direction opposite to the first direction (e.g., counterclockwise) to retract the projection screen 1 so that the projection screen 1 can be recovered in the outer casing 6. In the present embodiment, the retracting mechanism 2 includes a rotating tube 20 having a long cylindrical shape for supporting the entire projection screen 1. The turret 20 is housed in the outer casing 6 and is rotatable within the outer casing 6 for recovery or release of the projection screen 1. The length of the turret 20 is substantially the same as the length of the outer casing 6.

The projection screen 1 has a rectangular shape, and has a top edge 10, a bottom edge 11 and a picture area 14 between the top edge 10 and the bottom edge 11. The top edge 10 of the projection screen 1 is formed into a cylindrical shape, and the sleeve is connected. On the turret 20, or having other structures that can be combined and fixed to the turret 20, The projection screen 1 can be wound or attached to the cylindrical outer surface of the turret 20. The bottom edge 11 of the projection screen 1 is fixedly connected to a pull rod 12, and the pull rod 12 is located outside the outer casing 6. On the one hand, the projection screen 1 is flattened after being unfolded by its own weight, and the bottom of the projection screen 1 is blocked on the other hand. The edge 11 enters the inside of the outer casing 6. A pull ring 13 is disposed at a central position of the pull rod 12 to facilitate the operator to pull the projection screen 1 by hand.

Referring to Figures 3 to 5B, the power mechanism 3 is coupled to the retractable mechanism 2 for providing a recovery power to the retractable mechanism 2. In this embodiment, the power mechanism 3 is mounted inside the rotating pipe 20, and includes: a torsion spring 30, a supporting shaft 31 and a connecting seat 32, wherein the torsion spring 30 and the supporting shaft 31 constitute the power generation of the power mechanism 3. The connecting seat 32 is connected to the retracting mechanism 2 and rotatably connected to the power generating portion as will be described later.

The torsion spring 30 has a first pin 301 and a second pin 302. The support shaft 31 is a tubular long shaft which can be made of an aluminum tube or a rigid tube of any suitable material and has a first support end 311 and a second support end 312. A through hole 313 is formed in the support shaft 31 near the first support end 311, and penetrates through a tubular outer wall (not shown) of the support shaft 31 to communicate with an internal shaft hole (not shown). The connecting seat 32 has a cylindrical shape and is rotatably mounted on the second supporting end 312 of the supporting shaft 31. For example, the connecting seat 32 can be provided with a central recess (not shown) rotatably sleeved on the supporting shaft 31. The second support end 312 is on, so that the connecting seat 32 is rotatable relative to the support shaft 31. A cylindrical outer surface of the connecting seat 32 is provided with a groove 320 and a convex rib 321 located in the groove 320. A cylindrical end surface of the connecting seat 32 is provided with a sinking groove 322. The first pin 301 of the torsion spring 30 is fixed to the support shaft 31 through the through hole 313 of the support shaft 31, and the second pin 302 of the torsion spring 30 is sleeved on the rib 321 of the connecting seat 32 and accommodated. The torque spring 30 is disposed between the connecting seat 32 and the support shaft 31.

The power mechanism 3 and the retracting mechanism 2 are connected by connecting the connecting seat 32 and the rotating pipe 20 Together. In detail, a pin (not shown) extends through a pin hole 21 (Fig. 4) on the rotating tube 70, and is inserted into the sinking groove 322 of the connecting seat 32 so that the connecting seat 32 and the rotating tube 20 are inserted. The pins are coupled together so that the connecting seat 32 and the rotating tube 20 can be rotated together, thereby combining the power mechanism 3 and the retracting mechanism 2. When the projection screen 1 is pulled down or extended, the rotating tube 20 will rotate in the first direction (such as clockwise direction). Since the connecting seat 32 and the rotating tube 20 are pinned together, the connecting seat 32 will also rotate. The tube 20 is rotated in the clockwise direction. At this time, the second pin 302 of the torsion spring 30 rotates together with the connecting seat 32, and the first pin 301 is fixed on the support shaft 31, so the torsion spring 30 is deformed, and the elastic force energy is accumulated to recover the power. . When the projection screen 1 is released, the connecting seat 32 is rotated in the counterclockwise direction by the restoring force generated by the recovery power of the torsion spring 30, and the rotating tube 20 is also driven by the connecting base 32 to rotate in the counterclockwise direction. Therefore, the projection screen 1 is retracted into the outer casing 6.

In the present embodiment, the torsion spring 30 is formed by a coil spring and is sleeved on the support shaft 31. Therefore, by recovering the effective number of turns of the torsion spring 30, the recovery power generated by the torsion spring 30 can be adjusted and The amount of resilience generated by the recovery of power.

Referring to FIG. 3 and FIG. 6 to FIG. 9B, the self-locking mechanism 4 is coupled to the retracting mechanism 2 for positioning the projection screen 1 at any selected position. The self-locking mechanism 4 is disposed in the rotating pipe 20 together with the retracting mechanism 2 and is adjacent to the first end cover 7. The self-locking mechanism 4 includes: a self-locking shaft 40, a self-locking core 41, a self-locking jacket 42, and two balls 43 (only one ball is shown), wherein the self-locking shaft 40, the self-locking core 41 and The self-locking jacket 42 is made of a wear-resistant plastic material. The self-locking mechanism 4 and the retracting mechanism 2 are connected together by the self-locking outer casing 42 and the rotating pipe 20, and the detailed connection manner of the self-locking outer casing 42 and the rotating pipe 20 is described later.

The self-locking shaft 40 has a first end 401 and a second end 402. The first end 401 of the self-locking shaft 40 has a polygonal cylindrical structure, such as the four-slot cylinder structure shown in FIG. a complementary shaped column hole 71 provided inside the cover 7 (such as the four-sided edge shown in FIG. 7) In the column hole, it is fixedly connected to the first end cover 7, so that during the use of the projection screen apparatus 100, that is, during the release and recovery of the projection screen 1, the self-locking shaft 40 is always kept in a stationary state. The second end 402 of the self-locking shaft 40 has a cylindrical shape and is fixedly coupled to the first support end 311 of the support shaft 31 of the power mechanism 3, so that the support shaft 31 is also always fixed and stationary. In the present embodiment, the second end 402 of the self-locking shaft 40 is inserted into the inner shaft hole of the first support end 311 of the support shaft 31, and the first pin 301 of the torsion spring 30 penetrates through the support shaft 31. The through hole 313 and the pin hole 403 on the self-locking shaft 40 fix the two together. In the present embodiment, the self-locking shaft 40 and the support shaft 31 are coupled together and disposed together in the rotating tube 20, so the sum of the lengths of the two is not greater than the length of the rotating tube 20.

In addition to the through hole 313 of the support shaft 31 and the locking hole 403 of the self-locking shaft 40 through the first pin 301 of the torsion spring 30, a pin hole (not shown) may be additionally disposed on the support shaft 31, and the alignment may be performed. The pin holes 403 on the self-locking shaft 40 are sequentially passed through the pin holes of the support shaft 31 and the pin holes 403 of the self-locking shaft 40 by a pin (not shown) to pin the two together. In other different embodiments, an additional connection may be used between the self-locking shaft 40 and the support shaft 31. For example, the cylindrical outer surface of the second end 402 of the self-locking shaft 40 may be coupled to the first support end of the support shaft 31. The inner shaft hole of the 311 is an interference fit, and the two are directly connected. Alternatively, the self-locking mechanism 4 (the self-locking shaft 40 and the support shaft 31 of the power mechanism 3 are directly provided integrally to form a common shaft.

The self-locking core 41 is a substantially cylindrical member that is placed over the self-locking shaft 40. The cylindrical outer side surface of the self-locking core 41 is provided with at least one set of inner ball tracks 44, and in the present embodiment, three sets of inner ball tracks 44 are provided on the outer side surface of the self-locking core 41, and the inner ball track 44 is provided in each set. Each has a self-locking point. In this embodiment, the three sets of inner ball tracks 44 are 120 degrees rotationally symmetric with respect to the axis of the self-locking core 41, and the structures of the three sets of inner ball tracks 44 are the same, so only one set of inner balls is shown in the drawing. The structure of the track 44 will be described in detail below by taking the ball track 44 of the group as an example, and will not be described for other inner ball tracks.

As shown in FIG. 9A, the inner ball track 44 has a diagonal groove 440, a first curved groove 441, a second curved groove 442, a positioning groove 443, and a third curved groove 444. a fourth curved groove 445, wherein the first curved groove 441 and the fourth curved groove 445 are disposed around the outer surface of the self-locking core 41, and the oblique groove 440 is formed with respect to the axis of the self-locking core 41. The first communication path between the first and fourth curved grooves 441 and 445 is formed obliquely between the first curved groove 441 and the fourth curved groove 445. The positioning groove 443 constitutes a self-locking point on the inner ball track 44, and is disposed between the first curved groove 441 and the fourth curved groove 445, and is composed of the second curved groove 442 and the third curved groove 443. The first curved groove 441 and the fourth curved groove 445 are respectively connected to form a second communication path which is connected between the first and fourth curved grooves 441 and 445. The first curved groove 441 has a protruding guiding portion 4410 for guiding the ball 43 into the second communication path from the first curved groove 441 when rotating in the counterclockwise direction. Here, the counterclockwise rotation occurs when the rotation is performed from the clockwise direction and then the positioning is stopped. Please refer to it later. The fourth curved groove 445 also has a protruding guiding portion 4450 for guiding the ball 43 from the fourth curved groove 445 into the first communication path (ie, the oblique groove 440) when rotating in the clockwise direction. Here, the clockwise rotation occurs when the positioning is stopped to the counterclockwise direction, and the projection screen 1 needs to be pulled down first, so that the rotating tube 20 and the self-locking jacket 42 are rotated clockwise by a certain angle. It will be further explained below.

In order to facilitate the control of the stroke of the ball 43 on the ball track 44 in the self-locking core 41, the self-locking core 41 is sleeved and fixed on the self-locking shaft 40, and the relationship between the stroke of the ball 43 and the projection screen 1 and The working principle of the lock mechanism 4 will be described in detail later. In the present embodiment, the self-locking core 41 is fixed to the self-locking shaft 40 by the two switch springs 45, 46. In detail, a switch spring 45 or 46 is mounted on each side of the self-locking core 41. For example, a left-handed switch spring 45 is mounted on the left end surface of the self-locking core 41, and a right end is mounted on the right end face of the self-locking core 41. Rotary switch spring 46. When the self-locking core 41 is subjected to a clockwise driving force, A switch spring (left-handed switch spring 45) can prevent the self-locking core 41 from rotating clockwise, and when the self-locking core 41 is subjected to a counterclockwise driving force, the other switch spring (right-handed switch spring 46) The self-locking core 41 can be prevented from rotating counterclockwise, whereby the self-locking core 41 can be kept substantially in a stationary state.

In other embodiments, the self-locking core 41 can also be fixed to the self-locking shaft 40 by other means, or in other embodiments, the self-locking core 41 can also be rotatably sleeved on the self-locking shaft 40. Up, while still achieving its original function, only the stroke of the ball 43 in the inner ball track 44 becomes complicated.

The self-locking outer sleeve 42 is rotatably sleeved on the outer side surface of the self-locking core 41, and has a cylindrical inner side surface opposite to the outer side surface of the self-locking core 41, on which three sets of inner ball tracks 44 are provided with three sets of outer The ball track 420, the three sets of outer ball tracks 420 are 120 degrees rotationally symmetric with respect to the axis of the self-locking jacket 42. In the present embodiment, each set of outer ball tracks 420 is formed by a linear groove extending in the axial direction. The self-locking outer sleeve 42 has a first outer sleeve end 421 and a second outer sleeve end 422. A pin hole 423 is formed in the vicinity of the first outer sleeve end 421 to penetrate between the cylindrical outer surface and the inner side surface of the self-locking outer sleeve 42. . A pin (not shown) extends through a pin hole 22 provided in the rotating tube 20 and a pin hole 423 of the self-locking outer sleeve 42 to fix the self-locking outer sleeve 42 to the rotating tube 20, so the self-locking outer sleeve 42 and the rotating tube The 20 rotates together, and the self-locking core 41 remains substantially stationary, in other words, the self-locking outer sleeve 42 rotates relative to the self-locking core 41 as the rotary tube 20 rotates.

The ball 43 is disposed between the self-locking core 41 and the self-locking jacket 42 and is fitted and slid into the inner ball track 44 and the outer ball track 420. Since in the present embodiment, three sets of inner ball tracks 44 are symmetrically disposed on the self-locking core 41, and the self-locking outer casings 42 are symmetrically disposed with three sets of corresponding outer ball tracks 420, in practice, each set of corresponding inner ball tracks A ball 43 may be disposed in each of the 44 and outer ball tracks 420 to form an embodiment in which the three balls 43 are simultaneously slid in the corresponding inner ball track 44 and outer ball track 420. Only three balls 43 are the same When running, if any of the balls 43 has a problem, for example, the stroke is stuck, the entire projection screen device 100 must be disassembled to be repaired. Therefore, in the present embodiment, only two balls are used in the self-locking mechanism 4. At the same time, 43 can ensure that the self-locking mechanism 4 can generate sufficient self-locking force, has high safety of use, and the synchronization of the two balls 43 sliding and self-locking work is better.

The ball 43 is selectively locked to the self-locking point by the movement of the ball 43 between the inner and outer ball tracks 44, 420, so that the self-locking jacket 42 can be selectively locked with the self-locking core 41, thereby fixing the rotating pipe 20 At the desired location. In detail, when the self-locking jacket 42 is not locked by the ball 43 to the self-locking core 41, the self-locking jacket 42 can be driven by the rotating pipe 20 to rotate relative to the self-locking core 41, and when the self-locking jacket 42 is balled When the lock 43 is locked on the self-locking core 41, the self-locking outer sleeve 42 can pinch the rotary tube 20 so that the rotary tube 20 cannot be rotated. During the recovery and release of the projection screen 1, the two balls 43 slide in the respective inner and outer ball tracks 44 and 420, respectively, and selectively perform self-locking operations. The manner in which the self-locking mechanism 4 operates will be further described below.

In addition, a fixing post 424 (shown in FIG. 9A) extending in the axial direction of the self-locking casing 42 is protruded from the outer cylindrical end surface of the second outer casing end 422 of the self-locking outer casing 42 for connecting the deceleration coil 50.

The speed reduction mechanism 5 includes a reduction coil 50 and a fixed shaft 51. The reduction coil 50 is made of a metal material, and the fixed shaft 51 is made of a wear-resistant plastic material. The reduction coil 50 is preferably a spiral spring formed by a ring. The sleeve is sleeved on the fixed shaft 51 to generate a variable frictional force with the outer surface of the fixed shaft 51. The fixed shaft 51 is fixed to the power generating portion of the power mechanism 3, for example, to the support shaft 31 of the power generating portion. Referring to FIG. 13, when the deceleration coil 50 is rotated in the first direction (for example, clockwise direction), the deceleration coil 50 is in a relaxed state, and the deformation amount X is negative, and the deceleration coil 50 and the fixed shaft 51 are outside. The gap between the surfaces becomes larger, the frictional force F between the two approaches 0, and when the deceleration coil 50 is along the second When the direction (for example, the counterclockwise direction) is rotated, the deceleration coil 50 is tightened, the deformation amount X is positive, and the gap between the deceleration coil 50 and the outer surface of the fixed shaft 51 becomes small, so that the friction between the two increases. The larger the amount of deformation (the smaller the gap), the greater the frictional force F between the two.

Referring to Figures 10 and 11, in the present embodiment, the reduction coil 50 is indirectly connected to the retracting mechanism 2 (e.g., the rotating tube 20) by being attached to the self-locking casing 42 of the self-locking structure 4. Therefore, the speed reduction coil 50 can adjust the recovery speed of the storage mechanism 2, which will be described in detail later. In the present embodiment, the self-locking shaft 40 of the self-locking mechanism 4 is used as the fixed shaft 51 of the speed reduction mechanism 5, in other words, in the present embodiment, the fixed shaft 51 of the speed reduction mechanism 5 and the self-locking mechanism 4 are self-locking The lock shaft 40 is a common shaft. The deceleration coil 50 is rotatably mounted on the self-locking shaft 40 and coupled to the self-locking jacket 42 to form an indirect connection with the retracting mechanism 2 (i.e., the diverter 20). Of course, in other embodiments, the fixed shaft 51 of the speed reduction mechanism 5 and the self-locking shaft 40 of the self-locking mechanism 4 may be connected by a pin connection or other connection.

It is conceivable that in other embodiments, the reduction coil 50 can be directly connected to the power mechanism 3 (such as the connecting seat 32), for example, the fixed shaft 51 of the speed reduction mechanism 5 is fixedly coupled to the support shaft 31 of the power mechanism 3. One (or second) support end 311 (or 312). Alternatively, the fixed shaft 51 and the support shaft 31 are directly integrated to form a common shaft, and one end of the reduction coil 50 is fixedly coupled to the connecting base 32 of the power mechanism 3, whereby the speed reduction mechanism 5 can be indirectly connected to the retractable mechanism. The mechanism 2 (such as the turret 20) can also achieve the purpose of adjusting the speed of the projection screen 1 recovery. Alternatively, the reduction coil 50 is directly connected to the retracting mechanism 2 (for example, the rotating pipe 20). For example, one end of the deceleration coil 50 is directly fixed to the rotating pipe 20 to directly adjust the recovery speed of the retracting mechanism 2.

Referring to FIGS. 10 and 11, in the present embodiment, the deceleration coil 50 is rotatably sleeved on the self-locking shaft 40 and located in the self-locking jacket 42, and the deceleration coil 50 is disposed on the right-handed switch. The right side of the spring 46 is separated from the right-handed switch spring 46 by a spacer 47 to prevent the deceleration coil 50 and the right-hand switch spring 46 from interfering with each other. Deceleration coil The first end 52 is a free end that extends into the interior of the self-locking jacket 42 and abuts against the outer surface of the spacer 47, but does not form any with the spacer 47. The carding effect. The second end 53 of the deceleration coil 50 is a fixed end, and a fixing ring 530 is formed on the second end 53 . The fixing ring 530 can be inserted through the fixing post 424 of the self-locking jacket 42 . As shown in FIG. 9A, the second end 53 of the reduction coil 50 is fixed to the self-locking jacket 42, whereby the second end 53 can follow the retracting mechanism 2 in the first direction (eg, clockwise) Or the second direction (such as counterclockwise direction) is rotatably connected to the retracting mechanism 2. When the self-locking jacket 42 is rotated by the rotating tube 20 in the first direction (for example, clockwise direction), the deceleration coil 50 is driven by the self-locking jacket 42 to rotate in the first direction, and the deceleration coil 50 is loose. In the state of being engaged, the gap between the deceleration coil 50 and the self-locking shaft 40 is increased, and the friction between the two is reduced to negligible, so that the deceleration coil 50 can be freely rotated on the self-locking shaft 40. Therefore, when the deceleration coil 50 rotates in the first direction (for example, clockwise direction), the deceleration coil 50 does not hinder the rotation of the self-locking casing 42, and the self-locking casing 42 and the rotating pipe 20 can smoothly rotate together, and the deceleration coil 50 does not Provides a deceleration effect. When the self-locking jacket 42 is rotated by the rotating tube 20 in a second direction opposite to the first direction (for example, a counterclockwise direction), the deceleration coil 50 is driven by the self-locking jacket 42 to rotate in the second direction. The deceleration coil 50 is deformed and tightened on the self-locking shaft 40, so that the gap between the deceleration coil 50 and the self-locking shaft 40 is reduced, and a large frictional force is generated therebetween, so that the deceleration coil 50 is rubbed and rotated to be self-locking. On the shaft 40, as the rotational speed increases, the friction between the deceleration coil 50 and the self-locking shaft 40 is greater. Therefore, when the deceleration coil rotates in the second direction, the deceleration coil 50 generates rotation of the self-locking casing 42. There is a certain hindrance effect, and a variable frictional force is generated between the two, so that the self-locking jacket 42 can be decelerated together with the rotary tube 20.

The manner in which the deceleration coil 50 and the self-locking jacket 42 are connected is not limited to the manner in which the fixing ring 530 and the fixing post 424 are connected as described above. It can be understood that in other embodiments, an internally threaded hole can be provided on the outer cylindrical end surface of the second outer sleeve end 422 of the self-locking outer sleeve 42 and inserted through the fixing ring 530 of the reduction coil 50 by a screw and screwed in. Self-locking The second end 53 of the reduction coil 50 is fixed to the self-locking jacket 42 in the internally threaded hole of the outer casing 42, and the deceleration coil 50 is housed inside the self-locking jacket 42. In the present invention, the first end 52 and the second end 53 of the reduction coil 50 should not have their specific structures defined by the free end and the fixed end, respectively. For example, in other embodiments, the first end 52 of the reduction coil 50 can be As the fixed end, the second end 53 of the deceleration coil 50 is used as a free end. For example, if the deceleration coil 50 is installed outside the self-locking jacket 42, the first end 52 of the deceleration coil 50 is a The fixing end is formed with a fixing ring (the structure of which is the same as the structure of the fixing ring 530), and the first end 52 of the deceleration coil 50 can be fixed to the outside of the self-locking jacket 42 by means of screw locking. On the cylindrical end face, and oppositely, the second end 53 of the reduction coil 50 becomes a free end.

In another embodiment, as shown in FIG. 12, the speed reduction mechanism 5 may additionally include a clutch 54. The deceleration coil 50 is selectively connected to the clutch 54. The clutch 54 is connected to the retractable mechanism 4 through the self-locking mechanism 4. Agency 2. In this embodiment, the clutch 54 is a thin cylindrical device mounted on the self-locking shaft 40, and one side surface of the clutch 54 abuts against the cylindrical end surface of the second outer casing end 422 of the self-locking outer casing 42. And fixed to the self-locking jacket 2 by screw locking. A plurality of clutch teeth 540 are disposed on the other side surface of the clutch 54. In the present embodiment, the clutch teeth 540 are all beveled grooves, but in other embodiments, the clutch teeth 540 may also be oblique protrusions. In the present embodiment, the deceleration coil 50 is mounted on the self-locking shaft 40 and outside the self-locking jacket 42 . The first end 52 of the deceleration coil 50 abuts the clutch 54 and the first end 52 and the clutch teeth 540 . The shape of the beveled groove is adapted to be selectively engaged with the beveled groove of the clutch tooth 540, and the second end 53 of the deceleration coil 50 is a free end that is remote from the clutch 54. When the clutch 54 is rotated in the clockwise direction by the self-locking casing 42, the first end 52 of the deceleration coil 50 is disengaged from engaging the clutch teeth 540 of the clutch 54, and the deceleration coil 50 is not driven by the clutch 54. Rotating, the deceleration coil 50 is in a natural state, the gap between the deceleration coil 50 and the self-locking shaft 40 is large, and the deceleration coil 50 does not hinder the clockwise rotation of the clutch 54, the clutch 54 and the self The lock jacket 42 can rotate smoothly together. When the clutch 54 is rotated by the self-locking casing 42 in the counterclockwise direction, the first end 52 of the deceleration coil 50 is engaged with any of the clutch teeth 540 of the clutch 54, and thus is driven to rotate in the counterclockwise direction. At this time, the deceleration coil 50 is deformed and tightened to the self-locking shaft 40, and the gap between the deceleration coil 50 and the self-locking shaft 40 becomes small, and the deceleration coil 50 can be rubbed and rotated on the self-locking shaft 40, and the rotation speed is increased. Larger, the greater the friction between the deceleration coil 50 and the self-locking shaft 40, thereby creating a certain hindrance to the counterclockwise rotation of the clutch 54 to reduce the rotational speed of the clutch 54 and the self-locking jacket 42.

The clutch 54 and the reduction coil 50 of the aforementioned speed reduction mechanism 5 may be simultaneously mounted inside the self-locking jacket 42. At this time, the second end 53 of the reduction coil 50 is a fixed end fixedly connected to the self-locking jacket 42, and the first end 52 is also a fixed end, which can be selectively fixedly coupled to the clutch 54. When the clutch 54 rotates with the self-locking jacket 42 in the clockwise direction, the first end 52 of the deceleration coil 50 will disengage without engaging with the clutch teeth 540 of the clutch 54, but the second end 53 of the deceleration coil 50 can be By fixing the fixing ring 530 and the fixing post 424 to the self-locking jacket 42, the deceleration coil 50 can also be rotated in the clockwise direction. At this time, the deceleration coil 50 is in a relaxed state, and no deceleration is provided. When the clutch 54 rotates in the counterclockwise direction together with the self-locking jacket 42, the first end 52 of the deceleration coil 50 is engaged with any of the clutch teeth 540 of the clutch 54, and the second end 53 of the deceleration coil 50 is fixed to The self-locking jacket 42 is mounted, so that the deceleration coil 50 also rotates in the counterclockwise direction. At this time, the deceleration coil 50 is deformed and tightened on the self-locking shaft 40, thereby generating frictional resistance and providing a deceleration effect.

The following is a description of the principle of the pull-down (release), positioning, recovery, and deceleration of the projection screen 1 by taking the structure disclosed in an embodiment as an example.

When the operator pulls down the projection screen 1, the projection screen 1 drives the rotary tube 20 to rotate clockwise, the torsion spring 30 deforms and accumulates a certain recovery power, and the rotary tube 20 drives the self-locking jacket 42 to rotate clockwise. At the same time, the balls 43 in the self-locking structure will be in the self-locking jacket 42 The linear groove (ie, the outer ball track 420) slides left and right, and the ball 43 is driven by the linear groove 420 of the self-locking outer sleeve 42 and passes through the oblique groove 440 of the inner ball track 44 of the self-locking core 41, and Surrounding motion in the first curved groove 441. Referring to FIG. 14, during the pull-down process of the projection screen 1, that is, from time T0 to T1, since the rotary tube 20 and the self-locking jacket 42 both rotate in the clockwise direction, the deformation amount X of the reduction coil 50 is negative. No deceleration is provided. Therefore, the deceleration coil 50 does not affect the pull-down speed of the projection screen 1.

After the projection screen 1 is deployed downward by a certain distance, and the operator wants to position it, the operator stops pulling down, and the rotating tube 20 will rotate under the force of the restoring force of the torsion spring 30 (ie, rotates counterclockwise), and the ball 43 will be from the first The curved groove 441 enters the second curved groove 442 and slides into the positioning groove 443. At this time, the ball 43 is locked in the positioning groove 443 of the self-locking core 41, and the ball 43 cannot continue to slide to the left and right. The linear recess 420 of the outer sleeve 42 prevents the self-locking outer sleeve 42 from rotating, and the rotary tube 20 is pinned by the self-locking outer sleeve 42 and cannot be rotated, thereby positioning the projection screen 1. It can be seen that the projection screen device 100 of the present invention can realize the random positioning of the projection screen 1 by the self-locking structure, so as to stay at any position. Referring to FIG. 14, during the positioning process of the projection screen 1, that is, from the time T1 to T2, since the rotating tube 20 and the self-locking jacket 42 stop rotating, the deformation amount X of the deceleration coil 50 is turned from negative to zero. At this time, the reduction coil 50 is in a natural extension state.

When the projection screen 1 needs to be recovered, first, the operator should gently pull down the projection screen 1, the rotating tube 20 drives the self-locking jacket 42 to rotate clockwise by a certain angle, and the linear groove 420 drives the ball 43 to slide, so that the ball 43 is concave from the positioning. Slide out in slot 443. Then, the operator completely releases the projection screen 1. Under the action of the restoring force of the torsion spring 30, the rotating tube 20 drives the self-locking jacket 42 to rotate counterclockwise, and the ball 43 passes through the third curved groove 444 and the fourth curved groove 445. Once again entering the oblique groove 440, the projection screen 1 continues to be recovered upward, and the ball 43 will circulate in the oblique groove 440. At the same time, the deceleration coil 50 is driven by the self-locking jacket 42 to rotate counterclockwise, because the deceleration coil 50 will rub and rotate on the self-locking shaft 40, the deceleration coil 50 will have a certain hindrance to the counterclockwise rotation of the self-locking jacket 42, forcing the self-locking jacket 42 to rotate together with the rotating tube 20, and because the rotation speed of the deceleration coil 50 is larger, between the deceleration coil 50 and the self-locking shaft 40 The greater the frictional force, the greater the deceleration effect on the self-locking jacket 42 and the rotating tube 20, so the deceleration coil 50 can adjust the rotational speed of the self-locking jacket 42 and the rotating tube 20 in the counterclockwise direction, so that the self-locking jacket The rotational speed of the 42 and the turret 20 tends to be smooth, and finally the projection screen 1 is slowly retracted at a constant speed, thereby avoiding the impact damage caused by the instantaneous recovery in the conventional structure.

In the recycling process of the projection screen 1, as shown in Fig. 14, in the early stage of recovery (from time T2 to T3), since the restoring force from the torsion spring 30 received by the projection screen 1 is large, the recycling of the projection screen 1 is caused. The speed is large, and the rotation speed of the deceleration coil 50 is also large, so the deformation amount X of the deceleration coil 50 also tends to increase gradually. At this time, the deceleration coil 50 provides a significant deceleration effect to control the recovery of the projection screen 1. speed. However, in the later stage of recovery (from time T3 to T4), as the restoring force of the torsion spring 30 gradually becomes smaller, the recovery speed of the projection screen 1 is gradually smaller, and the rotational speed of the deceleration coil 50 becomes smaller, so the deformation amount X is also The tendency is gradually decreasing until the projection screen 1 is completely retracted into the outer casing 6, and the deceleration coil 50 is no longer deformed. Since the reduction coil 50 has a variable amount of deformation, variable friction can be generated, so that the projection screen 1 can be slowly retracted at a constant speed.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the present invention has been disclosed in the above preferred embodiments. However, it is not intended to limit the invention, and any one of ordinary skill in the art can make a few changes without departing from the spirit and scope of the invention. The scope of protection of the present invention is therefore defined by the scope of the appended claims. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention.

Projection screen device ‧‧100

Projection screen ‧‧1

Top ‧‧10

Bottom ‧ ‧ 11

Lever ‧‧12

Pull ring ‧‧13

Screen area ‧‧14

Retractable institution ‧‧2

Circling ‧ ‧ ‧

Pin hole ‧‧21,22

Power agency ‧ ‧

Torsion spring ‧ ‧ 30

First pin ‧‧‧301

Second pin ‧‧‧302

Support shaft ‧‧31

First support end ‧‧‧311

Second support end ‧‧‧312

Through hole ‧ ‧ 313

Connection seat ‧‧32

Trench ‧‧ ‧320

Rib ‧ ‧ 321

Sinking trough ‧ ‧ 322

Self-locking mechanism ‧‧4

Self-locking shaft ‧‧40

First end ‧ ‧ 401

Second end ‧‧ ‧402

Pin hole ‧‧‧403

Self-locking core ‧‧41

Self-locking jacket ‧ ‧ 42

Outer ball track ‧‧420

First coat end ‧ ‧ 421

End of second coat ‧‧‧422

Pin hole ‧‧ 423

Fixed column ‧ ‧ 424

Ball ‧‧43

Inner ball track ‧‧44

Slash groove ‧‧‧440

First curve groove ‧‧‧441

Guidance Department ‧‧4410

Second curve groove ‧‧‧442

Positioning groove ‧‧‧443

Third curve groove ‧‧‧444

Fourth curve groove ‧‧‧445

Guidance Department ‧‧4,450

Switch spring ‧‧‧45,46

Isolation film ‧‧47

Speed reduction mechanism ‧‧5

Deceleration coil ‧‧50

Fixed axis ‧‧11

First end ‧ ‧ ‧

Second end ‧ ‧ 53

Fixed ring ‧ ‧ 530

Clutch ‧‧54

Clutch teeth ‧ ‧ 540

Enclosure ‧‧6

First end cap ‧‧7

Four bobbin holes ‧‧71

Second end cover ‧‧8

Deformation ‧‧‧X

Friction ‧‧F

Time ‧‧‧T0, T1, T2, T3, T4

Fig. 1 is a schematic view showing the overall external structure of a projection screen apparatus according to an embodiment of the present invention.

Fig. 2 is a schematic view showing the internal structure after disassembling the outer casing, the first and second end caps shown in Fig. 1.

Figure 3 is a schematic exploded view of a projection screen apparatus according to an embodiment of the present invention.

Fig. 4 is a view showing the retracting mechanism of an embodiment of the present invention shown in Fig. 3.

Fig. 5A is a schematic view showing the combined structure of the power mechanism according to an embodiment of the present invention shown in Fig. 3.

Fig. 5B is a schematic exploded view of the power mechanism of an embodiment of the present invention shown in Fig. 3.

Fig. 6 is an exploded perspective view showing the power mechanism and the self-locking mechanism according to an embodiment of the present invention.

Figure 7 is a schematic view showing the assembly of the power mechanism and the self-locking mechanism according to an embodiment of the present invention, and the assembly relationship between the self-locking structure and the first end cover is shown.

Figure 8 is a schematic view showing the overall external structure of the self-locking mechanism according to an embodiment of the present invention.

9A and 9B are schematic exploded views of the self-locking mechanism according to an embodiment of the present invention.

10 and 11 are schematic diagrams showing the positional relationship between the speed reduction mechanism and the self-locking mechanism according to an embodiment of the present invention, wherein the reduction coil is coupled to the self-locking jacket by a fixing ring and a fixing post.

Figure 12 is a schematic view showing the positional relationship between the speed reduction mechanism and the self-locking mechanism according to another embodiment of the present invention, wherein the speed reduction coil is coupled to the self-locking jacket by a clutch.

Fig. 13 is a view showing the relationship between the amount of deformation of the deceleration coil and the frictional force according to an embodiment of the present invention.

Fig. 14 is a view showing the change of the deformation amount of the deceleration coil in the process of drawing, positioning and recycling of the projection screen according to an embodiment of the present invention.

Self-locking shaft ‧‧40

Self-locking core ‧‧41

Self-locking jacket ‧ ‧ 42

First coat end ‧ ‧ 421

End of second coat ‧‧‧422

Switch spring ‧‧‧45,46

Isolation film ‧‧47

Speed reduction mechanism ‧‧5

Deceleration coil ‧‧50

Fixed axis ‧‧11

First end ‧ ‧ ‧

Second end ‧ ‧ 53

Fixed ring ‧ ‧ 530

Claims (16)

A projection screen device comprises: a projection screen; a retracting mechanism coupled to the projection screen, selectively rotatable in a first direction to release the projection screen, and optionally along a Rotating in a second direction opposite to recover the projection screen; a power mechanism comprising a power generating portion and a connecting seat, the connecting seat being connected to the receiving mechanism and rotatably connected to the power generating portion, The power generating portion is configured to provide a regenerative power to the retracting mechanism to rotate the retracting mechanism in the second direction to recover the projection screen; and a speed reducing mechanism includes a fixed shaft and a deceleration coil, the fixing The shaft is fixed to the power generating portion, the speed reducing coil is sleeved on the fixed shaft, and one end of the speed reducing coil is rotatably connected to the receiving mechanism along the receiving mechanism in the second direction, wherein When the end of the deceleration coil rotates in the second direction, the friction between the deceleration coil and the fixed shaft increases, thereby reducing the recovery speed of the projection screen. The projection screen device of claim 1, wherein the speed reduction mechanism further comprises a clutch coupled to the retracting mechanism, the deceleration coil being selectively connectable to the clutch, when the clutch is along the When rotating in one direction, the deceleration coil is disengaged from the clutch and is not rotated by the clutch. When the clutch rotates in the second direction, the deceleration coil is engaged with the clutch to be rotated. The projection screen device of claim 2, wherein the end of the deceleration coil abuts against a side surface of the clutch, the side surface of the clutch is provided with a plurality of clutch teeth, when the clutch edge When the first direction is rotated, the end of the deceleration coil is disengaged from the clutch teeth of the clutch, and when the clutch is rotated in the second direction, the reduction The end of the speed coil is engaged with one of the clutch teeth of the clutch. The projection screen device of claim 3, further comprising a self-locking mechanism, and the clutch of the speed reduction mechanism is coupled to the retracting mechanism through the self-locking mechanism. The projection screen device of claim 4, wherein the self-locking mechanism comprises: a self-locking shaft fixed to the power generating portion; a self-locking core having a cylindrical shape and fixed on the self-locking shaft Having a cylindrical outer surface on which at least one inner ball track is disposed, the inner ball track has a self-locking point; a self-locking jacket rotatably sleeved on the self-locking core, and the retracting mechanism Connected, the self-locking jacket has a cylindrical inner side surface opposite to the outer side surface of the self-locking core, and is provided with at least one outer ball track corresponding to the inner ball track of the self-locking core; and at least one ball, The utility model is disposed between the self-locking core and the self-locking jacket, and is movable in the inner ball track and the outer ball track. The projection screen device of claim 5, wherein the deceleration coil of the speed reduction mechanism and the clutch are located outside the self-locking jacket, and the clutch is fixed to one of the self-locking jackets of the self-locking mechanism. End face. The projection screen device of claim 1, wherein the end of the deceleration coil is rotatably coupled to the retracting mechanism along the retracting mechanism in the first direction, and when the deceleration coil When the end of the end is rotated in the first direction, the friction between the deceleration spring and the fixed shaft is reduced. The projection screen device of claim 7, wherein the retracting mechanism comprises a rotatable rotating tube coupled to the projection screen and selectively along the first direction or The second direction is rotated to release or recycle the projection screen. The projection screen device of claim 8, wherein the power generating portion of the power mechanism comprises a torsion spring and a support shaft, and the connecting seat is rotatably mounted on one of the shaft ends of the support shaft, and The connecting seat is fixed on the rotating pipe and rotatable with the rotating pipe, and the torsion spring is disposed between the supporting shaft and the connecting seat. The projection screen device of claim 9, wherein the end of the reduction coil is coupled to the retractable mechanism through the connecting seat of the power mechanism, and the fixed shaft of the deceleration mechanism is coupled to the support shaft . The projection screen device of claim 9, wherein the torsion spring is a coil spring sleeved on the support shaft and has a first pin fixed to the support shaft; and a first Two pins are fixed to the connector. The projection screen device of claim 7, further comprising a self-locking mechanism, the end of the deceleration coil being connected to the retracting mechanism through the self-locking mechanism. The projection screen device of claim 12, wherein the self-locking mechanism comprises: a self-locking shaft fixed to the power generating portion; a self-locking core having a cylindrical shape and fixed on the self-locking shaft Having a cylindrical outer surface on which at least one inner ball track is disposed, the inner ball track has a self-locking point; a self-locking jacket rotatably sleeved on the self-locking core, and the retracting mechanism Connected, the self-locking jacket has a cylindrical inner side surface opposite to the outer side surface of the self-locking core, and is provided with at least one outer ball track corresponding to the inner ball track of the self-locking core; and at least one ball, The utility model is disposed between the self-locking core and the self-locking jacket, and is movable in the inner ball track and the outer ball track. The projection screen device of claim 13, wherein the end of the deceleration coil of the speed reduction mechanism is coupled to the self-locking jacket, and the self-locking shaft of the self-locking mechanism is coupled to the speed reduction mechanism The fixed shaft. The projection screen device of claim 14, wherein the deceleration coil of the speed reduction mechanism is received in the self-locking jacket, and the end of the deceleration coil extends to the outside of the self-locking jacket and is fixed to One end of the self-locking jacket. The projection screen device of claim 15 , wherein a fixing post is disposed on the end surface of the self-locking jacket, and a buckle is disposed on the end of the deceleration coil, and the buckle is sleeved on the fixing post. .