Roller screen unit

Abstract: In the roller screen unit of the present invention, a clutch mechanism based on a centrifugal effect using balls (8) is provided with a ratchet member (4) in which a cylindrical portion (9) has notches between engaging grooves (6) of a stator member (2) and floating grooves (7) of a rotator member (3). The roller screen unit of the present invention is also provided with a braking mechanism having a top member (24), for controlling rotation of a rotator member (17) during winding/housing of the screen member, centrifugally in contact with the inner peripheral surface of the rotator member. In addition, a connection portion (34, 43) having side edge turnups (34) or a beaded portion (43) is provided at an end of the screen member and are engaged with groove provided in the longitudinal direction of the roller sleeve to simplify and facilitate to attach the screen member to the roller sleeve.

Description: The present invention relates to a roller screen unit for a window or the like. An automatic winding type roller screen unit is known for example from US-A-4 345 636 in which torsion energy is accumulated in a spiral spring fixed in a roller sleeve when the screen member is drawn from the roller to facilitate subsequent winding of the screen member back on to the roller. The screen member may be a curtain, a blind, a light-weight shutter or a projection screen from the roller sleeve. In these conventional roller screen units, an end of the spiral spring is fixed to the interior of the roller sleeve attached with the screen member, and the other end thereof is connected to a pillow member rotatable with the roller sleeve, so that the spiral spring is caused to accumulate its torsion power when drawing and expanding the screen member, and the screen member is rolled up onto the roller sleeve by releasing the torsion power of the spiral spring. It is also possible in these roller screen units to stop the roller sleeve at a voluntary position. Drawing/expanding and winding/housing of the screen member and stoppage thereof at a desired position are achieved by a clutch mechanism provided on the roller screen unit. The clutch mechanisms conventionally known include, for example, the ratchet-type one in which the clutch is released by the centrifugal effect resulting from rotation movement during drawing and winding of the screen member, whereas during stoppage, an engaging pawl supported by a rotator member is engaged with the gear portion provided on a stator member rotatably engaging with the rotator member so as to cause downward falling under gravity, and the ball-type one in which a power roller or a power ball charged so as to come between inner and outer circumferences of a stator member and a rotator member engaging therewith is centrifugally released during drawing and winding of the screen member and is bitten between the stator member and the rotator member through free falling during stoppage. However, the above-mentioned clutch mechanisms using centrifugal effect are defective in that operations such as drawing/expanding, winding/housing and stopping of the screen member and re-drawing/re-expanding thereof after stoppage must be changed through subtle touch and timing of human operation. Depending upon the manual operation, therefore, the screen member sometimes fails to stop at a prescribed position and the screen member may suddenly be rolled up onto the roller sleeve, and these operational errors are inevitable in these types of conventional clutch mechanisms. For the purpose of solving these defects, a type simply changing over between ON and OFF such as a mechanical clutch mechanism is conceived, but this type requires frequent changeover between ON and OFF, thus resulting in very troublesome operations. Additionally the screen member is rapidly rolled up onto the roller sleeve, in a roller screen unit, during winding and housing of the screen member onto the roller sleeve. To avoid this inconvenience, braking means having various built-in reducing mechanisms have been employed to alleviate the winding speed of the screen member. As such braking means, for example, an acceleration type centrifugal brake based on friction with the inner peripheral surface of a fixed drum and an oil dumper type braking means have been known. However, the acceleration type centrifugal brake has such problems as the limitation in size of the braking member and noise upon braking. The oil dumper type braking means is defective in that a change in atmosphere temperature causes a change in viscosity of the braking fluid, and this in turn causes a change in the braking performance. In the conventional roller screen unit, furthermore, one of the technical problems to be solved is how to attach the screen member to the roller sleeve. It has been known as conventional practices, for example, to provide notches and projections of the roller sleeve, to form grooves on a supporting piece secured to the screen member, to insert the side edges of the supporting piece into the notches of the roller sleeve, and to engage the projections of the roller sleeve with the grooves on the supporting piece: this is one of the known attachment structures of the screen member to the roller sleeve, and a more simple attachment structure is known, which comprises inserting the supporting piece secured with the screen member into the notch provided on the roller sleeve. However, because the end of the screen member is also inserted into the notch on the roller sleeve, there is available only a very limited freedom for the thickness of the screen member. Kinds and thickness of the screen member capable of being attached have largely been restricted by the size of the notch formed on the roller sleeve. This restriction makes the attaching operation of the screen member to the roller sleeve troublesome, and the screen member would have unsteadiness for a thickness of the screen member outside a certain range, thus leading to a damage to the screen member. From US-A-4 345 636 there is provided a roller screen unit comprising a screen member that may be drawn from and wound upon a roller comprising, a clutch mechanism comprising a stator member having engaging grooves on the outer peripheral surface, a rotator member having grooves on the inner peripheral surface and rotatably engaging with said stator member, and balls engaging with the grooves of said rotator member . The present invention is characterised in that said stator member includes an engagement portion at one end engaging in only one rotational direction and in that the roller screen unit includes a ratchet member having a cylindrical portion extending at one end between the grooved surfaces of said stator member and said rotator member, said extension having notches therein, and engagement portions engaging in only one rotational direction at respective ends; and a rotating member having a friction piece, in contact with the inner wall of said rotator member, on the outer peripheral surface, and a projection, movably engaging with a groove other than the engaging grooves of said stator member, on the inner peripheral surface, and an engagement portion engaging in only one rotational direction at an end, said rotating member being urged against said ratchet member and being able to rotate within a limited angle. In a preferred embodiment of the present invention the roller screen unit includes a braking mechanism, comprising, rotatably supported on a second stator member, a second rotator member rotating in contact with the inner surface of said roller, a retainer and a sun gear, having planetary pinion gears rotating with rotation of the rotator member, connected through a gear portion provided on the inner peripheral surface of the rotator member, a top member, provided with a weight balancing member, in contact centrifugally with the inner peripheral surface of said rotator member, controlling rotation of said rotator member; and a second rotating member carrying said top member. Preferably the screen member is provided with a connecting portion that is engaged with a connecting groove provided in the longitudinal direction of said roller. An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which:- Fig. 1 is a partially cutaway sectional view illustrating an embodiment of the clutch mechanism in the roller screen unit of the present invention; Figs. 2 (a), (b) and (c), 3 (a), (b) and (c), and 4 (a), (b) and (c) are respectively partially cutaway left side views, partially cutaway front views and partially cutaway right side views illustrating operations of the clutch mechanism in the roller screen unit of the present embodiment; Figs. 5 (a) and (b), and 6 (a) and (b) are respectively partially cutaway left side views and partially cutaway right side views illustrating operations of the clutch mechanism in the roller screen unit of the present embodiment; Fig. 7 is a partially cutaway sectional view illustrating an embodiment of the braking mechanism in the roller screen unit of the present invention, together with an a stop mechanism for stopping the rotation of the rotator member; Fig. 8 is a perspective view illustrating the top member in the braking mechanism shown in Fig. 7; Fig. 9 is a sectional view illustrating the attachment structure of the screen member to the roller sleeve in the roller screen unit of the present invention; and Figs. 10 and 11 are respectively a sectional view and a perspective view illustrating another possible attachment structure of the screen member. As shown in Fig. 1, the roller screen unit accomplishes the drawing/expanding and winding/housing of various screen members, by using the torsion power of an integral spiral spring (1) through imparting/accumulating and releasing/restoring thereof. A rotator member (3), a ratchet member (4) and a rotating member (5) are rotatably engaged with the outer periphery of a fixed stator member (2). However, the angle of rotation of the rotating member (5) is limited within a certain range as described later. Plural, for example four, engaging grooves (6) are provided at prescribed positions on the outer peripheral surface of the stator member (2), and floating grooves (7) are provided on the inner peripheral surface of the rotator member (3). Balls (8) are floatably engaged with these floating grooves (7). The engaging grooves (6) and the floating grooves (7) are intermittently connected through notches formed on a cylindrical portion (9) provided on the extension of an end of the ratchet member (4). When the engaging grooves (6) are in line with the floating grooves (7), the balls (8) are held by the engaging grooves (6), the notches and the floating grooves (7) to prevent rotation of the rotator member (3). In the state shown in Fig. 1, the balls (8) are not held. Engagement portions (10a) and (11a) engaging only in one direction are formed at both ends of the ratchet member (4), and other engagement portions (10b) and (11b) are formed at an end of the stator member (2) and at an end of the rotating member (5) opposing engagement portions (10a) and (11a). Each of the engagement portions (10a), (10b), (11a) and (11b) may comprise any surface engagement means such as engagement of pawls on the inner and outer peripheral surfaces and other manners of engagement. The rotating member (5) has a friction piece (12) in contact with the inner wall of the rotator member (3) on the outer peripheral surface thereof, and has, on the inner peripheral surface thereof, projection (14) movably engaging with a groove (13) other than the engaging grooves (6) of the stator member (2). This rotating member (5) is pressed by the torsion power of a spring (15) against the ratchet member (4). The rotating member (5) changes the rotating direction intermittently along with rotation and stoppage of the rotator member (3) to control changeover between drawing/expanding and winding/housing of the screen member by balls (8). The clutch mechanism comprising the constitution as described above, for example, works as follows. Fig. 2 illustrates the stop state of the rotator member (3). The engaging grooves (6) of the stator member (2) conform with notches (16) of the cylindrical portion (9) of the ratchet member (4). The engaging grooves (6) and notches (16) are located at 90° intervals. There is a maximum phase difference of 45° between an engaging groove (6) and a notch of the cylindrical portion (9). The balls (8) can freely fall into the engaging grooves (6), the grooves 6, notches (16) and the floating grooves (7) of the rotator member (3), are in line and are held by these engaging grooves (6), the notches (16) and the floating grooves (7). At this point the projection (14) on the inner peripheral surface of the rotating member (5) is at the stop position as shown in Fig. 2 (c) relative to the groove (13) of the stator member (2). The angle α is , for example in this case, about 45°. The screen member is drawn and expanded from this state, and the rotator member (3) is caused to rotate in direction A. Rotation of the rotator member (3) is transmitted through the friction piece (12) to the rotating member (5), resulting in rotation of the rotating member (5). The engagement portion (11a) of the ratchet member (4) engages with the engagement portion (11b) of the rotating member (5), and the ratchet member (4) turns with the rotation of the rotating member (5). The engagement portion (10a) of the ratchet member (4) comes off, on the other hand, the engagement portion (10b) of the stator member (2) and slips on the latter engagement portion (10b). The cylindrical portion (9) also moves along with rotation of the ratchet member (4). This movement is shown in Fig. 3 on the assumption of an angle α of approximately 25°. At this moment, the engagement of the balls (8) is released. When rotation is continued by about 45° from the state shown in Fig. 2 to an angle α of 0°, the state shown in Fig. 4 is achieved. At this point, the movement of the cylindrical portion (9) by about 45° causes the cylindrical portion (9) to fully block the engaging grooves (6). As is clear from Fig. 4 (c), on the other hand, movement of the projection (14) is prevented by the groove (13) irrespective of rotation of the rotator member (3) in direction A, and thus the rotating member (5) does not rotate. In this state, rotation of the rotator member (3) does not result in the balls (8) moving into the engaging grooves (6). The rotator member (3) rotates while slipping on the friction piece (12). The screen member can be drawn and expanded by rotation of the rotator member (3). Then, when manual drawing/expanding of the screen member is discontinued, winding/housing of the screen member is started in a direction opposite to direction A as described above under the effect of the torsion power of the spiral spring (1). Frictional force between the friction piece (12) and the rotator member (3) causes the rotating member (5) to rotate and move to a position with an angle α of about 45° of the projection (14). More particularly, the state as shown in Fig. 5 is achieved. In this state, the engagement portions (11a) and (11b) of the ratchet member (4) and the rotating member (5) do not engage with each other, but the rotating member (5) rotates while slipping on the ratchet member (4). The engagement portion (10a) of the ratchet member (4) is in engagement with the engagement portion (10b) of the stator member (2). The rotator member (3) rotates further while slipping on the friction piece (12), and thus winding/housing of the screen member is accomplished. In order to stop the screen member at a desired position, this winding is discontinued and the screen member is slightly drawn and expanded again in direction A. Then, the engagement portion (10a) of the ratchet member (4) comes off the engagement portion (10b) of the stator member (2), and at the same time, the other engagement portion (11a) engages with the engagement portion (11b) of the rotating member (5). Frictional force between the rotator member (3) and the friction piece (12) causes rotation of the rotating member (5) through rotation of the rotator member (3) until the position with an angle α of 0° is reached, while the ratchet member (4) also rotates. When the condition of α = 0° is achieved, the cylindrical portion (9) of the ratchet member (4) moves by 45° from the state shown in Fig. 5, and thus the engaging grooves (6) conform with the notches (16). This state is illustrated in Fig. 6. When manual operation of drawing/expanding of the screen member is discontinued in this state, the rotator member (3) and the rotating member (5) rotate in an opposite direction under the effect of the torsion power of the spiral spring (1) and achieve again the state with an angle α of about 45° as shown in Fig. 2. In this state, the balls (8) are held by the engaging grooves (6), the notches (16) and the floating grooves (7) to stop the rotator member (3). While the rotating member (5) rotates by about 45°, the engagement portion (11b) of the rotating member (5) slips on the engagement portion (11a) of the ratchet member (4), thus not causing the ratchet member (4) to rotate. As a result, the cylindrical portion (9) of the ratchet member (4) keeps the position shown in Fig. 6 to allow engagement of the balls (8) in the engaging grooves (6). With a clutch mechanism in the roller screen unit as described above, drawing/expanding of the screen member and stoppage thereof at a desired position are accomplished, from a stopped position (Fig. 2), in accordance with a cycle consisting of: [I] drawing of the screen member (Fig. 3), [II] release of drawing, spontaneous rewinding (Fig. 4) (Fig. 5), [III] drawing of the screen member (Fig, 6), and [IV] release of drawing, stoppage (Fig. 2). This cycle, being mechanically stepwise, is easy to operate. A clutch mechanism based on centrifugal effect and mechanical ratchet mechanism is achieved. The present invention thus provides a roller screen unit easy to use, which permits simple operations without depending upon human touch and timing as in the conventional operations. As shown in Fig. 7, the roller screen unit further comprises a braking mechanism. The braking mechanism has a retainer (19) and a sun gear (20) as rotating members having planetary pinion gears (18) rotated by rotation of a rotator member (17) other than the above-mentioned one, through the gear portion of the inner peripheral surface of rotator member (17), which rotates in contact with the inner surface of the roller sleeve. A particular combination of the group of planetary pinion gears and the sun gear makes available a large braking force with a small torque. The sun gear (20) may have a plural constitution to implement a larger braking force with a smaller torque. A clutch mechanism (22) other than that described above is provided between the retainer (19) and another stator member (21) other than the above-mentioned one for positive/negative rotation adjustment. As this clutch mechanism (22), any of various structures including a ball clutch mechanism may be adopted. A rotating member (26) other than that described above comprising a top member (24) supported with a pin (25) mounted with a weight balancing member (23) which controls rotation of the rotator member (17) by means of frictional force resulting from the centrifugal contact with the inner peripheral surface of the rotator member (17) through rotation of the planetary pinion gear (18) of the sun gear (20) is rotatably supported by the stator member (21). The stator member (21), being secured by a rectangular pin (27), never rotates. In the braking mechanism having the construction described above, the rotator member (17) is braked from the inside thereof by means of the frictional force caused by the centrifugal effect of the top member (24), for the purpose of braking the rotational acceleration of high-speed rotation of the rotator member (17) when the screen member is rolled up upon releasing of the torsion power of the spiral spring (1) shown in Fig. 1, for example. Rotation of the rotator member (17) is transmitted through the planetary pinion gear (18) and the rotating member (26) to the top member (24). Then, the top member (24) is directed outside with the pin (25) as the center. The centrifugal force at this moment is increased by the presence of the weight balancing member (23) such as a ball member, thus increasing the frictional force with the inner peripheral surface of the rotator member (17). An arrangement of the top member (24) and the rotating member (26) is illustrated in Fig. 8. In this arrangement the top member (24) is each provided with two ball-type weight balancing members (23). The top member (24) expands in direction B around the pin (25), and presses the rotator member (17), in contact with the inner peripheral surface thereof. The braking mechanism shown in Fig. 7 is provided with a stop mechanism for stopping rotation of the rotator member (17). The stop mechanism is achieved by the horizontal movement in direction C of a boss member (30) which rotates by means of an engaging portion (29) provided on the inner surface of a spline (28) that rotates with rotation of the rotator member (17). This boss member (30) moves through the geared portion of the shaft of the fixed stator member (21). Under the effect of the spline (28) rotating upon rolling up the screen member, the boss member (30) moves in direction C, and comes into contact with the fixed portion (31) of the stator member (21), particularly with the end face thereof provided with an O-ring (32). In this state, the boss member (30) can no longer be moved. A braking force, therefor, acts on the rotator member (17) so as to stop rotation thereof. The O-ring (32) plays a role of a shock absorber in this case. In the braking mechanism of the roller screen unit, for example, in the arrangements as described above, the braking force can easily be controlled through adjustment of the weight balancing member (23) provided on the top member (24), and it is possible to appropriately change the design and manufacture thereof in response to the scale and performance of the roller screen unit. The boss member (30) may have a smaller pitch and/or a smaller-diameter to achieve a more compact size of the unit. By using the clutch mechanism previously described together with this braking mechanism, there is provided a roller screen unit excellent in operational convenience, which permits simple and easy operations of drawing/expanding and winding/housing of the screen member and changeover between these operations, and allows accurate stoppage of the screen member. The clutch mechanism and the braking mechanism may, for example, be provided respectively at both ends of the roller sleeve. It is needless to mention that there is no restriction in the manner of providing these mechanisms. In addition, the roller screen unit has a structure for attaching the screen member to the roller sleeve as described below. As shown in Fig. 9, for example, in a hard sheet member (36) having a projection (33) and side edge turnups (34)(35), a screen member (37) is secured to one of the side edge turnups (34), and the other side edge turnup (35) forms a curved surface identical with the outer peripheral surface of the roller sleeve (38). The hard sheet member (36) may be made, for example, of hard vinyl chloride resin. The side edge turnup (34) securing the screen member (37) may, on the other hand, be made of soft vinyl chloride resin. Securing the screen member (37) may be accomplished through fastening with an adhesive or an adhesive double coated tape, or through thermal fastening or sewing. Attachment of the hard sheet member (36) securing the screen member (37) to the roller sleeve (38) is accomplished through insertion of the leading ends of the side edge turnup (34) and the hard sheet member (36) into a notch (39) formed on the roller sleeve (38) and engagement of the projection (33) of the hard sheet member (36) with a groove (40) provided on the roller sleeve (38). This allows simpler attachment operation with a single touch. Furthermore, since this attachment structure of the screen member (37) to the roller sleeve (38) does not require insertion of the screen member (37) into the notch (39), attachment of the screen member (37) is never restricted by the thickness thereof. So far as the thickness of the leading ends of the hard sheet member (36) and the side edge turnup (34) corresponds to the size of the notch (39), the screen member (37) of any thickness may be attached to the roller sleeve (38). Attachment of the screen member to the roller sleeve may also be based on any of the structures illustrated in Fig. 10 and 11. It is made possible to attach the screen member (37) to the roller sleeve (38) through insertion of a beaded portion (42) provided at an end of the screen member (37) into a groove (41) provided on the roller sleeve (38) of the roller screen unit. The screen member (37) is never inserted into the groove (41) of the roller sleeve (38), and the roller sleeve (38) is secured only at the beaded portion (42). The thickness of the screen member (37), therefore, never affects the attachment. When attaching the screen member (37) to the roller sleeve (38), as shown in Fig. 11, the beaded portion (42) is inserted into the groove (41) from the end of the roller sleeve (38) in direction C. Thus, the screen member (37) can be attached to the roller sleeve (38). When removing the screen member (37), it is sufficient to draw the beads portion (42) in direction E. The beaded portion (42) may be achieved by fixing a threadlike cord connecting beads made of such as a resin, a metal or a ceramic material to an end of a cloth (43) and connecting this cloth (43) to the screen member (37) through adhesion, fastening or sewing. More preferably, this may be achieved, for example, by weaving the cloth (43) with thermal fastening yarn as the woof and/or the warp, fixing the beaded string made by connecting beads with the threadlike cord to the cloth (43) by thermally fastening to an end of the screen member (37). In addition, it is also possible to provide the beaded string directly at an end of the screen member (37). Different variations are applicable as to the shape and the size of this beaded string. The attachment structure of the screen member to the roller sleeve as described above permits simple and easy attachment of the screen member to the roller sleeve, even with a single touch. A roller screen unit free from any restriction by kinds or thickness of the screen member is thus provided. Furthermore, absence of unsteadiness in the screen member after attachment enables the prevention of damage at the end of the screen member.

Claims: A roller screen unit comprising a screen member (37) that may be drawn from and wound upon a roller and a clutch mechanism comprising a stator member (2) having engaging grooves (6) on the outer peripheral surface, a rotator member (3) having grooves on the inner peripheral surface and rotatably engaging with said stator member, and balls (8) engaging with the grooves of said rotator member; characterised in that said stator member includes an engagement portion (10b) at one end engaging in only one rotational direction and in that the roller screen unit includes a ratchet member (4) having a cylindrical portion (9) extending at one end between the grooved surfaces of said stator member and said rotator member, said extension having notches (16) therein, and engagement portions (10a, 11a) engaging in only one rotational direction at respective ends; and a rotating member (5) having a friction piece (12), in contact with the inner wall of said rotator member, on the outer peripheral surface, and a projection (14), movably engaging with a groove (13) other than the engaging grooves of said stator member, on the inner peripheral surface, and an engagement portion (11b) engaging in only one rotational direction at an end, said rotating member being urged against said ratchet member and being able to rotate within a limited angle. A roller screen unit as claimed in claim 1 comprising, a braking mechanism, comprising, rotatably supported on a second stator member (21), a second rotator member (17) rotating in contact with the inner surface of said roller, a retainer (19) and a sun gear (20), having planetary pinion gears (18) rotating with rotation of the second rotator member, connected through a gear portion provided on the inner peripheral surface of said second rotator member; a top member (24), provided with a weight balancing member (23), in contact centrifugally with the inner peripheral surface of said second rotator member, controlling rotation of said second rotator member; and a second rotating member (26) carrying said top member. A roller screen unit as claimed in Claim 2, comprising a stop mechanism having a boss member (30), for stopping rotation of the braking mechanism rotator member (17), in contact with the fixed portion of the braking mechanism stator member (21), after horizontal movement while rotating with rotation of said braking mechanism rotator member. A roller screen unit as claimed in claim 1, 2 or 3 wherein said screen member (37) is provided with a connecting portion that is engaged with a connecting groove provided in the longitudinal direction of said roller. A roller screen unit as claimed in Claim 4, which comprises: a notch (39) and a groove (40) provided in the longitudinal direction of the roller, a hard sheet member (36) having a projection (33) secured at an end of the screen member (37) and turned up side edges (34, 35), wherein the screen member is attached to the roller through insertion of the leading ends of one of said side edge turnups (34) and the hard sheet member into said notch and engagement of said projection with said groove. A roller screen unit as claimed in Claim 5, wherein: a said side edge (34) of the hard sheet member (36) securing the screen member (37) is made of a soft flexible member. A roller screen unit as claimed in Claim 4, wherein a beaded portion (42) is provided at an end of the screen member (37) which is inserted into the groove (41) provided in the longitudinal direction of the roller. A roller screen unit as claimed in Claim 7, wherein: a beaded connecting cloth (43) comprising a beaded string made by connecting beads by means of a threadlike cord, and provided on a cloth woven with thermal fastening yarn, is thermally fastened to an end of the screen member (37).

Inventors: CHIGUSA TOMOMICHI C O METACO C, TSUCHIDA OSAMU C O METACO CO L, CHIGUSA, TOMOMICHI, C/O METACO CO. LTD., TSUCHIDA, OSAMU, C/O METACO CO. LTD.
Applicants: METACO KK, METACO CO., LTD.
Application year: 1990
Main classification: E06B9
IPC codes: E06B9, G11C5