CORDLESS CURTAIN AND GUIDE BRAKING UNIT THEREOF

The present invention provides a cordless curtain and guide braking unit thereof, wherein the guide braking unit includes a fixing mount and a round rod shaped metal wire that is wound round to form a slide sheering member. The fixing mount is configured with a bottom block, and a pull cord through hole is provided in the center of the surface thereof. The slide sheering member is provided with a circular through-hole and fastening rod members, wherein the circular through-hole is axially positioned corresponding to the pull cord through hole, with the fastening rod members fixed to two sides of the circular through-hole. The inner circular edge of the circular through-hole is used to provide the pull cord with cornering slippage, which protects the various system components and produces the desired damping effect.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a cordless curtain and guide braking unit thereof, and more particularly to a curtain comprising horizontal slats with no exposed pull cord, wherein a guide braking unit is used to guide and brake the internal pull cord.

(b) Description of the Prior Art

To ensure safe usage of curtains, curtains without exposed pull cords have been developed, which use a spring motor formed from a winding and unwinding mechanism to obtain a feedback force, whereby during the process of pulling down a lower rail at the curtain hem of the curtains, the energy from a pull-down motive force on the internal pull cords is transmitted and stored in an internal spring of the winding-unwinding mechanism through a winding-unwinding wheel. And during the operation of retracting the curtain upwards, the arms of a user first upwardly sets in motion the lower curtain hem to eliminate static friction of the curtain system, after which the energy stored by the spring inside the winding and unwinding mechanism effects a feedback output via the pull cords to retract and pull the lower rail upwards, thereby achieving a self-contained take-up curtain function of a self-retracting curtain.

Referring toFIG.1, which shows a damping unit of the prior art, wherein a pull cord is used to raise and lower curtain slats by means of a spring motor70, whereby the pull cord passes over steering damper rods2131of a guide braking unit20, and then connects to curtain slats. In this cord configuration, the pull cord is hidden in the slats and an upper rail comprising a winding-unwinding mechanism, and cannot be seen from the outside. Accordingly, such a curtain system is commonly referred to as a cordless curtain.

The steering damper rods2131are usually fixed and not rotatable, providing a damping capacity in addition to having a cord steering guidance function.

The guide braking unit20guides the direction of a pull cord S1connected to the spring motor70and is transversely installed with the at least one steering damper rod2131, which enables the pull cord S1to wind therearound to change the direction thereof and generate a primary side friction damping. In one embodiment of the prior art, if a higher damping value is required, after winding round the steering damper rod2131, the pull cord S1then winds round another steering damper rod2131on a corresponding side opposite to the first steering damper rod2131, to enable generating a secondary cumulative damping effect. Finally, because the pull cord S1needs to hang down to link together curtain slats50, thus, the pull cord S1needs to turn direction and be lowered from the center of a bottom block212by passing through an admittance hole11provided in an upper beam10corresponding to the hole position in the center of the bottom block212.

This turning in direction of the pull cord S1relies on the cornering sheering of a to-and-fro opening61provided in a riveted ring60that is coaxially encased in a through hole24positioned in the center of the bottom block212, thereby preventing direct friction between the lip, made of plastic or metal, of the through-hole24and the pull cord S1being pulled therethrough. The lower end of the riveted ring60is coaxially embedded inside the circular space of the admittance hole11.

In the prior art, the riveted ring60enabling the pull cord S1to corner and sheer thereover is a primary thin metal tube, which is coaxially riveted to the through hole24provided in the bottom block212.

As a result of the riveted ring60being riveted to the through hole24(as shown inFIG.2), the basic form of the riveted ring60is preshaped from a thin metal tube with a slip lip opening62. After the lower end of the thin metal tube passes through the depth of the through hole24, a spread crimping operation is carried out on the lower end thereof, forming split braids66that inverse clasp to the lower end edge of the through hole24.

The method used to form the split braids66involves expanding the lower end opening of the riveted ring60to produce cracks64therein using a jig at the beginning of a crimp riveting operation, and then causing the plurality of cracks64to split and form the split braids66.

The split braids66are then bent to form inverse clasps that clamp onto the edge of the through hole24, thereby achieving coaxial joining of the riveted ring60and the through hole24.

During the expansion operating procedure, because the riveted ring60is made from thin metal material, split openings63are liable to spread out due to radial expansion, and due to the extent of the excessive widening of the extended axial cracks64, there is a good chance that a crack end portion65will upwardly extend, first entering the wall of the to-and-fro opening61, then extending to enable slide sheering contact of the pull cord S1with the slip lip opening62. Moreover, because the body wall of the round tube has split cracks, preexisting formed stresses on the cracks64(the crack end portion65) result in unbalanced forces and separate deformations occurring, which cause respective corresponding two cracks on two sides of the cracks64or the crack end portion65, forming different drop heights in the enclosed ring surface, and causing corresponding cracked edges to form protruding or sunken sharp edges.

Under the above-described circumstances, when the slide sheering cord body of the pull cord S1is operating, generally, excessive extension of the crack end portion65or the respective sharp edges formed on the cracks64results in scuffing and breaking of the pull cord S1occurring. And because the riveted ring60is formed by punching thin metal, If the pull cord S1is thick, after a certain period of time, cuts will form thereon due to sliding friction.

Referring toFIG.2-1, which shows a related system damping, which apart from the above-described conflagration, a pair of the steering damper rods2131are additionally horizontally positioned directly above the through hole24of the bottom block212, which are used to guide the routing direction of the pull cord S1to a transverse direction, thereby enabling the pull cord S1, after cornering over the steering damper rods2131, to pass through the through hole24and hang down.

The through hole24is similarly coaxially riveted with the above-described riveted ring60. and the cracks64and the extended crack end portion65are similarly produced on the inner ring wall of the to-and-fro opening61and the slip lip opening62of the riveted ring60.

The pull cord S1passes over the corresponding circumferential surfaces of the steering damper rods2131, and under the effect of an external force, the cord body of the pull cord S1will not be fixedly positioned on the longitudinal surfaces of the steering damper rods2131and waver thereon. When the pull cord S1deviates from the vertical projected area range of the inner circumference of the to-and-fro opening61, then the cord body of the pull cord S1will rub against the inner circumference surface of the to-and-fro opening61, and with the addition of the extant cracks on the to-and-fro opening61, the surface of the passing cord body of the pull cord S1is liable to being cut.

SUMMARY OF THE INVENTION

The present invention is fitted with a metal wire wound round and formed as an integral body, which together with a slide sheering member provided with a damping effect are stably positioned on the bottom portion of a guide braking unit, enabling safe slide sheering of a pull cord and providing the required damping function.

The guide braking unit comprises a fixing mount and the slide sheering member, wherein the fixing mount comprises a bottom block and a pair of side walls. The pair of side walls are respectively connected to the two sides of the bottom block, and the center of the bottom block is internally provided with a pull cord through hole.

The slide sheering member is fixed to the upper portion or the lower portion of the bottom block and coaxially corresponds to the pull cord through hole. Fastening rod members connect to two sides of a circular through-hole.

The present invention further provides a cordless curtain, comprising an upper beam, a plurality of curtain slats configured below the upper beam, a pair of guide braking units, which are fixed to the two internal sides of the upper beam; and a pair of angle controllers, which are respectively positioned at the sides of the guide braking units inside the upper beam. Each of the guide braking units comprises the fixing mount, a ladder cord suspending hub, and the slide sheering member.

If the system requires a light damping effect, the slide sheering member of the present invention directly enables the pull cord configured to a spring motor to turn downward and link up with the curtain slats, to form a primary cornering and one-time light value damping effect.

If the system requires a higher damping effect, one or more steering damper rod(s) can be additionally fitted to each of the guide braking units in the direction receiving the pull cord, thereby enabling primary or more than two-time cornering of the pull cord inside each of the guide braking units, to form at least two cornering cumulative damping values in conjunction with the slide sheering member.

To enable a further understanding of said objectives, structures, characteristics, and effects, as well as the technology and methods used in the present invention and effects achieved, a brief description of the drawings is provided below followed by a detailed description of the preferred embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Regarding the embodiments of the present invention, first refer toFIG.3, which shows a cordless curtain and guide braking unit thereof of the present invention, wherein a cordless curtain100comprises an upper beam10, a plurality of curtain slats50configured below the upper beam10, a pair of guide braking units20fixed to the interior of the upper beam10, and a pair of angle controllers30, which are respectively positioned at the sides of the guide braking units20.FIG.3only shows one of the guide braking units20and one of the angle controllers30for reference; the other end of the upper beam10is installed with the other guide braking unit20and the other angle controller30. Furthermore,FIG.3omits a winding-unwinding mechanism.

A portion of each of the angle controllers30extends to the exterior of the upper beam10and connects to a rotating member32. A ladder cord S2is wound around a ladder cord suspending hub22of the guide braking unit20, and the ladder cord S2passes downward through the guide braking unit20and the upper beam10, connecting to the curtain slats50. Rotating the rotating member32drives a gear wheel (not shown in the drawings) inside the angle controller30, which drives a linkage rod40, which then rotates the ladder cord suspending hub22of the guide braking unit20, thereby pulling the ladder cord S2and adjusting the angle of the curtain slats50.

Referring toFIGS.4to7, which show the guide braking unit20comprising a fixing mount21, the ladder cord suspending hub22, and a slide sheering member23.

The fixing mount21is roughly U-shaped, and comprises a bottom block212and a pair of side walls211, which are respectively connected to the two sides of the bottom block212. A pull cord through hole2120) is provided in the bottom block212close to the central portion thereof, and the pair of side walls211of the fixing mount21are wedged inside the upper beam10.

The ladder cord suspending hub22is rotatable configured to the pair of side walls211. More specifically, a pin connecting indentation2110is formed in each of the side walls211, and the two ends of the ladder cord suspending hub22are respectively rotatable pivoted on the pin connecting indentations2110.

The slide sheering member23is fixed to the bottom block212, wherein the slide sheering member23is provided with a circular through-hole232and fastening rod members234. The circular through-hole232is positioned on the pull cord through hole2120of the bottom block212, and the fastening rod members234connect to the two sides of the circular through-hole232. The fastening rod members234extend toward the bottom block212and are fixed to two sides of the circular through-hole232.

The slide sheering member23of the present embodiment is formed as an integral body by bending and winding round a metal wire with a circular cross-section. And the above-described fastening rod members234are respectively connected in a winding configuration to two opposite sides of the circular through-hole232through the center point thereof.

The fixing mount21further comprises a pair of socket bases214, which are respectively positioned on two sides of the pull cord through hole2120, and the above-described pair of fastening rod members234are respectively insertedly fixed to the pair of socket bases214, thereby completing the assembly. More specifically, the fastening rod members234assume L shapes, and each of the socket bases214upwardly assumes a U-shape, as well as forming plug holes2140that are perpendicular to the bottom block212. A stopping portion2142is formed on the two inner side surfaces of each of the socket bases214. Portions (or so called horizontal sections) of the fastening rod members234of the slide sheering member23parallel to the bottom block212are wedged into the stopping portions2142; and portions (or so called vertical sections) of the fastening rod members234perpendicular to the bottom block212are respectively inserted into the plug holes2140, wherein the plug holes2140pass through the bottom surface of the bottom block212. Hence, in another embodiment of the slide sheering member23, the slide sheering member23can downwardly penetrate the plug holes2140through to the bottom surface of the fixing mount21, thereby enabling the fastening rod members234to penetrate and be clasped to the bottom surface of the fixing mount21from the bottom upwards.

As a supplementary description, the bottom block212of the fixing mount21is further provided with a pair of outer cord holes2122, which are respectively positioned to the sides of the above-described pair of socket bases214at a distance thereto. The ladder cord S2is wound around the ladder cord suspending hub22, and then downwardly passes through the pair of outer cord holes2122of the bottom block212.

An opening2112and a side axle seat213is formed in each of the side walls211of the fixing mount21, wherein the openings2112roughly assume a rectangular shape, and each of the side axle seats213is configured with a steering damper rod2131that enables a pull cord S1to wind therearound (seeFIG.6).

Referring toFIG.8, the slide sheering member23is made from a metal wire with a circular cross-section, wherein the wire can be further provided with elastic stress. The two fastening rod members234of the formed slide sheering member23extend outward from the outer circumference of the circular through-hole232on two sides thereof, outwardly extending in opposite directions from two sides of the slide sheering member23corresponding to a line L through the center of the circular through-hole232, wherein a plane angle between the extended directions forms a deflection prestress angle θ, enabling the two fastening rod members234of the slide sheering member23to be respectively aligned and assembled in the two plug holes2140. After being assembled, an elastic counteracting force generated when the prestress angle θ is changed is stopped by the rod body of each of the fastening rod members234pressing against a contiguous elevation2141configured on each of the stopping portions2142. The contiguous elevations2141are at the same angle of orientation to the corresponding line L, wherein the contiguous elevations2141and the plug holes2140enable the fastening rod members234to be assembled and fixed therein, after which the elastic stress of the prestress angle θ is used to generate a planar snap force, which causes the slide sheering member23to be elastically pressed against and stably positioned in the socket bases214. Moreover, the elastic stress is used to absorb the vibrations generated by the crossing-over movement of the pull cord S1.