UNEQUAL-TORQUE COIL SPRING AND A SPRING MOTOR THEREOF

Abstract

An unequal-torque coil spring and a spring motor thereof which is adapted for a curtain set that can automatically fold back a curtain; the same provides a feedback torque that responds to different stages of a curtain-folding working process and generates various corresponding torque in response, as each of the different stages requires a different force. Consequently, the curtain can be folded back at a steady speed, and positionally fixed at any height when the curtain is lowered.

Claims

1. An unequal-torque coil spring, wherein feedback torque is provided in response to requirements of unequal forces at a loading end, mainly comprises a long strip of reed strip; the reed strip has different sections longitudinally disposed from a front end to a rear end thereof, and the sections have different curvatures formed by getting coiled and bent inwards to generate different torque; an exposed end serving as a joining end, wherein the reed strip has torque distributed as follows: an increasing torque is implemented between the joining end and a first length, a first torque that follows the increasing torque and slowly increases is implemented between the first length and a second length, a second torque that follows the first torque and is equal to a maximum value of the first torque is implemented between the second length and a third length, a third torque that follows the second torque and gradually decreases is implemented between the third length and a fourth length, and a fourth torque that follows a minimum value of the third torque and gradually decreases is implemented between the fourth length and a fifth length.

2. The unequal-torque coil spring according to claim 1, wherein the unequal-torque coil spring generates usable feedback torque values with a ratio between 4:1.

3. A spring motor being applied in a curtain set, which steadily folds a curtain and allows a lower beam to be lowered and fixed at any heights, comprising: a housing; a first reel drum and a second reel drum being axially parallel to each other and located at two sides inside of the housing at a same height; an axle and a coiling axle being axially parallel to each other and located centrally inside the housing at a same height; a chainring axially linked to an end of the first reel drum; a chainring axially linked to an end of the second reel drum; a chainring being axially movable at an end of the axle; a linking chainring axially linked to an end of the coiling axle; each of the chainrings and the linking chainring are of a same diameter, and are arranged and engaged from a front end to a rear end; an unequal-torque coil spring for providing feedback torque in response to requirements of unequal forces at a loading end, mainly comprises a long strip of reed strip; the reed strip has different sections longitudinally disposed from a front end to a rear end thereof, and the sections have different curvatures formed by getting coiled and bent inwards to generate different torque; an exposed end serving as a joining end, wherein the reed strip has torque distributed as follows: an increasing torque is implemented between the joining end and a first length, a first torque that follows the increasing torque and slowly increases is implemented between the first length and a second length, a second torque that follows the first torque and is equal to a maximum value of the first torque is implemented between the second length and a third length, a third torque that follows the second torque and gradually decreases is implemented between the third length and a fourth length, and a fourth torque that follows a minimum value of the third torque and gradually decreases is implemented between the fourth length and a fifth length; the unequal-torque coil spring being axially and movably sleeved outside of a cylindrical surface of the axle, the disposed joining end is joined to a radial cylindrical surface of the coiling axle.

4. The spring motor according to claim 3, wherein the unequal-torque coil spring generates usable feedback torque values with a ratio between 4:1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a front structural view of an assembly of a curtain set according to the prior art.

[0024] FIG. 2 is a three-dimensional structural view of a spring motor according to the prior art.

[0025] FIG. 3 is an assembled structural top view of the spring motor according to the prior art.

[0026] FIG. 4 is a schematic view showing the requirement of force for the curtain-folding process of a curtain set.

[0027] FIG. 5 is a lateral status view showing a lower beam of a curtain set located at the middle of a full lift height.

[0028] FIG. 6. is a three-dimensional schematic view showing a reed strip of the present invention being bent into a first curvature.

[0029] FIG. 7. is a three-dimensional schematic view showing the reed strip of the present invention being bent into a second curvature.

[0030] FIG. 8. is a three-dimensional schematic view showing the reed strip of the present invention being bent into a third curvature and a fourth curvature.

[0031] FIG. 9. is a schematic view showing the reed strip of the present invention being bent into unequal curvatures at a front end and a rear end.

[0032] FIG. 10. is a top view of the reed strip of the present invention being bent into an unequal-torque coil spring.

[0033] FIG. 11 is a top view of an assembled system where the present invention is applied to a spring motor.

[0034] FIG. 12 is a correspondence view of the feedback torque curve of the present invention that corresponds to the requirements for the curtain-folding process in a curtain set.

[0035] FIG. 13 is another preferred embodiment showing the torque curve implemented by the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] The present invention provides an unequal-torque coil spring and a spring motor thereof, which uses a simple method for disposing different curvatures in multiple front and rear sections of a reed strip, so as to provide a feedback force as multiple levels of torque in response to actual working requirements from a curtain system loading end capable of arranging a curtain at different heights, and having dynamic and static friction forces between working pieces of the system, so that the curtain can be folded back and a lower beam can be fixed at any positions.

[0037] Referring to FIGS. 6-8 (with reference to FIG. 9), the present invention provides a strip of a reed strip 3 having different curvatures disposed as different levels, with an initial curvature A0, a first curvature A1, a second curvature A2, a third curvature A3 and a fourth curvature A4. Each of the unequal curvatures is made by bending the strip toward an identical inner circle. Each of the different curvatures are disposed in the same reed strip 3, and because the electronic spatial structures of different sections of the strip are modified by bending, the resulted elastic reactions of the different sections are different, which gives rise to unequal elastic forces (torque) output from different sections of the strip.

[0038] Referring to FIG. 9 again, the reed strip 3 of the present invention has an initial curvature A0 disposed in a section starting from a joining end 300 to a first length L1, and a torque generated therefrom is an increasing torque TC that increases suddenly; a first curvature A1 disposed in a section starting from the first length L1 to a second length L2, and the first curvature A1 generates a first torque T1 which is of a slowly increasing arc when viewed on the curvature graph; a second curvature A2 disposed in a section starting from the second length L2 to a third length L3 to form a second torque T2, and the second torque T2 is a constant torque which is of a curve extending from a highest torque output of the first torque T1 when viewed on the curvature graph; a third curvature A3 disposed in a section starting from the third length L3 to a fourth length L4, and the curvature of the third curvature A3 decreases to form a third torque T3; a fourth curvature A4 disposed in a section starting from the fourth length L4 to a fifth length L5, and the curvature of the fourth curvature A4 can be made less to form a smaller fourth torque T4 (points connecting the above-described torque curves are not changed suddenly, but have lines preceding and following the points slowly changing, the description about the points is omitted for the purpose of simplification).

[0039] For the purpose of meeting the requirement of forces corresponding to the actual curtain-folding working process, as well as easy fabrication, the reed strip 3 is fabricated by bending several sections separately to allow for the generation of several different torque forces, wherein the second torque T2 is the maximum, and the third torque T3 following the second torque T2 decreases by sloping downwards; the torque forces after the fifth length L5 are not included for consideration.

[0040] Referring to FIG. 10, in which a structure of the formed unequal-torque coil spring 30 can be simplified into 3 layers overall; a curvature of an inner spiral layer C3 gradually becomes less than that of an outer spiral layer C1, and a curvature of a mid spiral layer C2 is also less than that of the outer spiral layer C1. Under a stationary condition, the unequal-torque coil spring 30 can form a self-binding force toward a center thereof to maintain a circular shape.

[0041] A ratio between the above-described torque forces can be set between 4:1, and the reed strip 3 is formed into an unequal-torque coil spring 30 by coiling, and comprises the outer spiral layer C1, the mid spiral layer C2, the inner spiral layer C3 and a joining end 300 disposed at an exposed end of the reed strip 3.

[0042] Referring to FIG. 11, the unequal-torque coil spring 30 of the present invention is implemented in a housing 201 of a spring motor 2, the unequal-torque coil spring 30 is sleeved outside of a cylindrical surface of an axle 23 around an identical center, but is not linked to the axle 23; the joining end 300 disposed at a free end of the reed strip 3 is joined to a cylindrical surface of a coiling axle 24 and linked thereto; an end of the coiling axle 24 is linked to a linking chainring 240, and when driven by a chainring 220 of a second reel drum 22 or a chainring 210 of a first reel drum 21, the linking chainring 240 drives the unequal-torque coil spring 30 to coil toward the direction of the coiling axle 24. Under a stationary condition, the outer spiral layer C1 of the unequal-torque coil spring 30 has the maximum torque and is the first to be coiled into the outer circle of the coiling axle 24; when outputting a feedback torque, the outer spiral layer C1 is the last to be output.

[0043] Referring to FIG. 12, the spring motor 2 is applied in a curtain set 1 for folding back a curtain 15. Torque required for curtain-folding is different between a first height H1, a second height H2, a third height H3, a fourth height H4 and a fifth height H5. If a lower beam 14 is folded to a position between the third height H3 and the second height H2, the spring motor 2 withstands a maximum torque that is the second torque T2; the distance between the second height H2 and the first height H1 is the last folding step and is the shortest, and the remaining momentum from the second torque T2 generated for the curtain-folding process is sufficient for uploading a total mass W of the stacked curtain pieces. Therefore, the first torque T1 is only used for pulling and supporting an overall weight resulted from accumulating the total mass W of all stacked curtain pieces 150 and preventing the curtain 15 from falling downward, so the torque of the first torque T1 can be gradually decreased as it approaches the position of the first length L1. In other words, the torque from the first length L1 is able to withstand the total mass W of the stacked curtain pieces.

[0044] The second torque T2 generated from the longitudinal section of the reed strip 3 from the second length L2 to the third length L3 is a constant torque that corresponds to the curtain-folding process from the third height H3 to the second height H2 in the curtain set 1; when the curtain 15 is folded upwards, the torque T2 provides the maximum torque for the lower beam 14 to withstand the loading weight of curtain pieces sequentially accumulated on a top surface thereof, and for pulling the lower beam 14 to the second height H2. Subsequently, the first torque T1 is used to return the lower beam 14 to the first height H1. The purpose of having the first torque T1 less than the second torque T2 is to ease a momentum generated from the mass of the curtain 15 and the rising speed before the curtain 15 is folded back to destination (the first height H1), so that a buffering effect can be achieved before the curtain-folding completes, thereby ensuring safe use.

[0045] The third torque T3 generated from the section of the reed strip 3 from the third length L3 to the fourth length L4 is a decreasing torque, and the fourth torque T4 generated from the section from the fourth length L4 to the fifth length L5 is less than the third torque T3; the load of the fourth torque T4 is the smallest.

[0046] During the folding of curtain, the lower beam 14 is pulled upwards from the fifth height H5 and starts to sequentially accumulate each of the curtain pieces 150 arranged above, and then the third torque T3 takes over as more force is needed for folding when the lower beam 14 reaches the fourth height H4, and the third torque T3 rapidly generates a higher torque to relay the folding process to the second torque T2.

[0047] Each of the described levels of torque is able to generate a stopping and fixing force according to any needs when the lower beam 14 is located at any positions within a total lift height H0, so as to prevent the lower beam 14 at a particular height to fall downwards or rise upwards.

[0048] In this embodiment, the reed strip 3 corresponds to a measurement of the total lift height H0, and the torque distribution is as follows: the first torque T1 is generated from the section between the first length L1 and the second length L2, the second torque T2 is generated from the section between the second length L2 and the third length L3, the third torque T3 is generated from the section between the third length L3 and the fourth length L4, and the fourth torque T4 is generated from the section between the fourth length L4 and the fifth length L5.

[0049] The curve graph shows the second torque T2 as one that needs to withstand a greater torque, and the third torque T3 and the fourth torque T4 can both be decreasing. This method of implementation can achieve a very steady speed for folding the curtain 15. In a most ideal system of mechanics, the most precise curve lines are distributed in a sloping torque curve based on geometric coordinates. But for the purpose of easily manufacturing the unequal-torque coil spring and providing forces required for folding the curtain 15, the torque distribution of the present invention is implemented according to the requirements of force for folding the curtain in the curtain set 1.

[0050] In another simple embodiment (refer to FIG. 13 and complemented by FIG. 12), the torque curve T0 of the present invention starts from zero and reaches the first length L1 at a great angle of elevation, and achieves a force of 0.5 Kg that is the first torque T1, for instance. The first torque T1 is generated from a level between the first length L1 and the second length L2, and the torque curve of the first torque T1 can be a sloping line or an arc. The second torque T2 generated from the section between the second length L2 and the third length L3 is the maximum constant torque; the third torque T3 generated from the section between the third length L3 and the fourth length L4 decreases at a great downward sloping rate or as an arc; the fourth torque T4 generated from the section between the fourth length L4 and the fifth length L5 is constant.

[0051] The above described second torque T2 and fourth torque T4 are both constant, and can satisfy the requirements of force for folding the curtain in the curtain set 1. In the process of fabricating the unequal-torque coil spring, the fabrication process is mainly focused on the second torque T2 and the fourth torque T4, so that the fabrication procedures can be made easier and the making of the torque curve T0 is more convenient.

[0052] The present invention provides different feedback torque in a reed strip by implementing different curvatures in each of the sections thereof; the distribution of different torque is well suited for providing feedback forces corresponding to different torque requirements of the curtain-folding process in the curtain set 1. Accordingly, a new patent application is proposed herein.

[0053] It is of course to be understood that the embodiments described herein is merely illustrative of the principles of the invention and that a wide variety of modifications thereto may be effected by persons skilled in the art without departing from the spirit and scope of the invention as set forth in the following claims.