Abstract:
A curtain blind power conversion device with reverse brake effect, wherein the power conversion device particularly provides the brake effect and power conversion during course of manipulating slats of the curtain blind. The power conversion device is structured to include a first annular gear and a second annular gear, the two annular gears having different circular pitch and coaxially configured face to face. The first annular gear is fixedly configured, whereas the second annular gear passively rotates, and the two annular gears synchronously engage with a single planetary gear set. Utilization is made of the unequal circular pitch of the two annular gears to produce an angular speed difference, where upon the second annular gear being subject to an external force feedback, the reverse brake effect is thereby assuredly achieved.

Description:
BACKGROUND OF THE INVENTION 
   (a) Field of the Invention 
   The present invention relates to a curtain blind power conversion device with reverse brake effect, and more particularly to the conversion device that provides a power terminal that achieves torsional conversion and the reverse brake effect for horizontal or vertical curtain blinds. The conversion device primarily utilizes two annular gears, wherein number of teeth and module of the two annular gears are unequal. The two annular gears synchronously engage with a single planetary gear set, and utilization is made of the unequal circular pitch and module of the two annular gears to produce an angular speed difference, thereby realizing a deceleration output motive force, and with the planetary gear set being subject to a fixed restriction of a first annular gear, the reverse brake effect is thereby achieved. 
   (b) Description of the Prior Art 
   Primary application of the present invention is in usage as a reverse brake for curtain blinds. Referring to  FIG. 1 , which shows a conventional curtain blind  1 , wherein, in order to achieve object of the reverse brake, the curtain blind  1  is configured with a drive unit  12  having an energy potential. 
   The drive unit  12  is actuated by means of a worm gear  124  (see  FIG. 2 ) through a worm  125  utilizing a relatively high slip ratio of inclined screw teeth. Wherein the worm  125  is driven by means of a sprocket wheel  126  through manual operation of a beaded chain  121 , whereby turning power generated is same as that obtained by means of an electric motor  20  substituting for the sprocket wheel  126 . 
   The drive unit  12  synchronously drives two take-up tubes  123  through an angle-shaped transmission rod  122  (see  FIG. 1 ). The take-up tubes  123  actuate slats  14  configured lower to the take-up tubes  123  by means of pull wires  141 , thereby taking up and letting down the slats  14  therewith. Anti-glare angle of the horizontal slats  14  is regulated by adjustment of angle of elevation through tilt leaves  13  actuating ladder cords  142 . 
   However, because the aforementioned curtain blind  1  is fitted on a window, force of wind blowing from outside causes the curtain blind  1  to move, and thereby results in the slats  14  sliding down. After the slats  14  have slid down, motive force of the wind consequently effectuates a reverse direction transmission to the drive unit  12  through the take-up tubes  123 , and indirectly through the transmission rod  122 , subsequently the drive unit  12  is subject to a relatively large external force feedback, which produces slippage thereat. 
     FIG. 2  depicts an improved brake configuration presently employed in curtain blinds, and because the worm gear  124  is positioned within a top horizontal rail  11 , dimensions of the brake configuration is small in proportion, moreover, force is transmitted to a single tooth of the worm gear  124  through engagement with the worm  125 , which thus forms a tooth surface pressure on a large single spot, subsequently the worm gear  124  or spiral teeth of the worm  125  are easily damaged, causing dislodging of the gears to occur, and thereby object of locking is lost. 
   Furthermore, the aforementioned drive unit  12 , in similar fashion, can actuate taking up and letting down of cloth curtains, and similarly, because of effect of the force of wind pressure and own weight of the cloth curtains, the cloth curtains also require the drive unit  12  to provide an effective reverse brake. 
   Referring to  FIG. 2A , which shows another horizontal type curtain blind having a traditional design primarily embodying a lift-drop cord  140  and a slat tilt rod  120 , wherewith the slats  14  are taken up or let down, and angle of incident light is adjusted. Basic configuration comprises the top horizontal rail  11  and the horizontal slats  14  connected lower thereof. Adjustment to the slats  14  is carried out by pull operating on the lift-drop cord  140 , thereby achieving raising and taking up of the slats  14  or letting down and unfolding of the slats  14 . Upon unfolding of the slats  14 , the slat tilt rod  120  is employed to regulate the angle of incidence the slats  14  make with incoming light; moreover, the slat tilt rod  120  effectuates linkage with the worm  125  thereof. Through the worm  125  rotatedly engaging with the worm gear  124 , the worm gear is thereby enabled to outwardly actuate the transmission rod  122 , whereupon regulating angle of incident light for the slats  14  can thereby be realized. Furthermore, utilizing the worm  125  engaging with the worm gear  124  can achieve an external force that effectuates an opposing brake effect. 
   Because the horizontal type slats  14  are generally fitted at a maximum elevation of approximately 30 feet. Because, firstly, dimensions of packaging is restrictive, and secondly, if the slat tilt rod  120  is utilized to regulate angle of incoming light, then length of the slat tilt rod  120  must also be close on 30 feet in length, thus the long slat tilt rod  120  is unsuitable for usage. Hence, a sprocket drive method is adopted in replacement of the slat tilt rod  120 . 
   Referring to  FIG. 2B , which shows the sprocket drive method, which traditionally operates in coordination with satellite gears to enlarge torsional force and effectuate a brake configuration. The sprocket drive is primarily configured for the beaded chain  121  to actuate the sprocket wheel  126 , and the sprocket wheel  126  actuates a conversion drive in a direction of the transmission rod  122  through a planetary gear set  18 . The planetary gear set  18  is subject to a motive power from the sprocket wheel  126  linkage to a sun gear  181 . Satellite gears  182  of the outer meshing ring are also subjected to corresponding meshing with a fixed annular gear, thereby enabling an attached carrier plate  180  to corotate. The carrier plate  180  externally connects to a shaft  190 , and after the shaft  190  is distanced from a brake spring  192 , linkage actuation of an output shaft  191  is effectuated. The output shaft  191  is externally linked to the transmission rod  122 , and the brake spring  192  utilizes space between an external surface of the shaft  190  and the output shaft  191  to implement operation of radial opening or internal shrinkage, thereby if a transmission force is transmitted to the axle  190 , the output shaft  191  will be subject to effect of the brake spring  192 , and a constraint reacting force is generated thereat, thus achieving object of stopping reverse movement. 
   The principle of the constraint reacting force is such that one end of the brake spring  192  is peripherally fixed, thereby enabling diameter of the brake spring  192  to be variated through an axial torsion, for instance, when the diameter of the brake spring  192  is reduced, the constraint reacting force effect is thereupon generated. Design of the brake spring  192  is that of a mechanical design of a general brake spring for a curtain rail, and thus is not described in further detail herein. 
   Referring to configuration of  FIG. 2B , the sprocket drive depicted applies a similar related drive structure as shown in  FIG. 1 , whereby the single beaded chain  121  achieves letting down and opening of the slats  14  and regulation of the angle the slats  14  make with irradiating light. 
   Although utilizing the beaded chain  121  enables achieving the various aforementioned functions, wherein the brake effect utilizes the constraint of reaction force or letting down operation or opening operation of the brake spring  192 . However, upon the constraint reaction force and circumferential surface of the shaft  190  surpassing a critical limit, slippage still occurs and thus loss of locking functionality thereof. 
   Referring to  FIG. 3 , which shows a conventional design for a vertical curtain blind, wherein the drive unit  12  is configured in the top rail  11 , and vertical slats  14  are connected to hanging shafts  15  configured below the top rail  11 . The drive unit  12  is similarly actuated through an external force by means of manual operation of an operating cord  16 . 
   Referring to  FIG. 4 , which shows an umbrella gear set  17  connected to one of the hanging shafts  15 , below which is connected the slats  14 . The umbrella gear set  17  is subject to horizontal actuation from the angle-shaped transmission rod  171 , and whereby the transmission rod  171  is subject to actuation from the drive unit  12 . 
   Utilizing actuation of the drive unit  12  thereby enables the umbrella gear set  17  to transfer drive to the hanging shafts  15 , which thereon connectively actuate the slats  14 , and thus realizes regulating angle of incident light hitting the slats thereof. However, surface pressure from force of natural wind effectuates producing a twisting phenomenon on the slats  14 , which thereby blows the slats  14  into disorder, and thus the originally appropriately angled slats  14  become disorientated. Hence, a requirement for a braking method fitted on the drive unit  12  is necessary to effectively brake the angle-shaped transmission rod  171 . 
   In order to prevent the transmission rod  171  from being subject to a reverse force from the hanging shafts  15 , which is thereby indirectly transmitted to the drive unit  12 , configuration of the drive unit  12  generally follows a structural principle depicted in  FIG. 2 , whereby a worm and a worm gear are utilized to achieve the brake effect. However, teeth of the worm and the worm gear are similarly subject to possibility of easily being damaged. 
   Recently, the brake effect utilizes a configuration embodying a magnetic-type mechanical control switch or other automatic devices having electrical components. However, electrical power is necessary in order to utilize such devices, and, moreover, configuration comprises complicated components. 
   SUMMARY OF THE INVENTION 
   In order to effectively accomplish a reverse brake effect, and simultaneously achieve deceleration conversion, the present invention utilizes a first annular gear and a second annular gear coaxially configured face to face. Module and circular pitch of the two annular gears are unequal, however, measure of pitch diameter is such that synchronous engagement with a single planetary gear set is realized. 
   Wherein the module of the planetary gear set is equal to that of the first annular gear, moreover, because the first annular gear is fixedly configured to a housing, thus after a sun gear has engaged with the planetary gear set, the second annular gear is thereupon engaged, and because periphery of the second annular gear set is not fixed, thus, after the planetary gear set has been actuated, the planetary gear set rotates with an angular speed difference, and rotational transmission is realized to an output shaft terminal thereof. 
   An external end of the second annular gear is connected to an output shaft, which connectively actuates an angle-shaped transmission rod. Upon the angle-shaped transmission rod being subject to an external force and thus a feedback counterforce being generated, which will be first transmitted to the second annular gear, whereupon the second annular gear will first engage with the planetary gear set. However, gear rack of another end of the planetary gear set engages with the fixed first annular gear, and is thus subject to limiting lock of the first annular gear, thereby achieving the reverse brake effect. 
   To enable a further understanding of the said objectives and the technological methods of the invention herein, the brief description of the drawings below is followed by the detailed description of the preferred embodiments. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows an elevational schematic view of a general horizontal curtain blind. 
       FIG. 2  shows a structural schematic view of a conventional drive unit. 
       FIG. 2-A  shows a front schematic view of a conventional horizontal curtain blind. 
       FIG. 2B  shows a structural view of the conventional drive unit utilizing a beaded chain to drive same. 
       FIG. 3  shows a structural schematic view of a conventional vertical curtain blind. 
       FIG. 4  shows a schematic view of an angled transformer device of the conventional vertical curtain blind. 
       FIG. 5  shows a structural elevational view according to the present invention. 
       FIG. 6  shows a side view of gear engagement relationship according to the present invention. 
       FIG. 7  shows a basic structural elevational view of an output terminal according to the present invention. 
       FIG. 8  shows an elevational view of braking effect of the output terminal according to the present invention. 
       FIG. 9  shows a front view of state of the output terminal rotational speed ratio according to the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With regard to an embodiment of the present invention, referring to  FIG. 5 , which shows a conversion device  10  that acquires a reverse motive force through an electric motor  20  or manually, and thereon through a sun gear  22  transmission. The conversion device  10  comprises a first annular gear  2  and a second annular gear  3 , wherein the two annular gears  2  and  3  are coaxially configured face to face. 
   The first annular gear  2  is externally fixed to a housing  4  by means fixing members  21  (see  FIG. 6 ). An external end of the second annular gear  3  is connected to an output shaft  30 . A center of the output shaft  30  is directed outwards and actuates an angle-shaped transmission rod  31 , whereby functionality of the transmission rod  31  is same as the angle-shaped transmission rods depicted in  FIGS. 1 ,  2 ,  3  and  4 . 
   A limiting disc  32  is further configured on a body of the output shaft  30 , and apart from the limiting disc  32  having functionality that allows the annular gear  3  to be radial movable fixed, the limiting disc  32  is also subject to containment in a holding groove  410  of a slide support  41  (see  FIG. 6 ) by means of an edge surface of the limiting disc  32 . Thus, if the angle-shaped transmission rod  31  is subjected to an external force, which thereby forms an extrusion push in a longitudinal direction, the limiting disc  32  being movable fixed, thereupon maintains axial positioning thereat. The extrusion force is that inclined frictional inverted acting force generated after the aforementioned slats  14  have been subjected to a force transmitted from the transmission shaft  31 . The axial extrusion acting force is a phenomenon often seen in a conventional curtain blind configured with the take-up tubes  123  (see  FIG. 1 ). 
   With further reference to  FIG. 6 , the first annular gear  2  and the second annular gear  3  are coaxially configured so as to form a relative abutment there between, moreover, the first annular gear  2  is fixedly configured to the housing  4  by means of the fixing members  21 . An output terminal of the second annular gear  3  locks on and thereby is connected to the angle-shaped transmission rod  31  by means of a fixing member  33 . The limiting disc  32  configured on the body of the output shaft  30  being subject to sliding placement in the holding groove  410  of the fixed slide support  41  thereby maintains radial and axial movable fixing thereof. 
   The sun gear  22  engaging with the planetary gear set  230  actualizes transmission to entire motive power input terminal. Width of each of the satellite gears  23  is sufficient to synchronously engage with the first annular gear  2  and the second annular gear  3 , thus the two annular gears  2  and  3  are subject to synchronous meshing by the single planetary gear set  230 . The satellite gears  23  are movably fixed to one triangular support  5 . 
   Circular pitch (cp) of the first and second annular gears  2  and  3  are unequal, wherein the circular pitch of the second annular gear  3  is relatively smaller than that of the first annular gear  2 , whereas, in contrast, number of teeth (t) of the second annular gear  3  is relatively greater than number of teeth of the first annular gear  2 , and the additionally configured number of teeth on the second annular gear  3  are in accordance with number of satellite gears  23 , wherein three satellite gears  23  are configured in the embodiment of the present invention, and, accordingly, an additional three teeth are configured on the second annular gear  3 . Employing the formula module=pitch diameter/number of teeth (m=d/t), under condition whereby the pitch diameter (d) is fixed, and the number of teeth t are altered, thus the module m similarly undergoes change as a result. 
   Furthermore, the circular pitch (cp) equals π (pi: ratio of a circumference of a circle to diameter) multiplied by the pitch diameter, and subsequently divided by the number of teeth (cp=πd/t). Under the previous conditions of the pitch diameter d being a constant factor, and the number of teeth t being altered, the circular pitch cp similarly changes as a result. 
   Referring to  FIG. 7 , which shows an arrangement of a gear system of the present invention, and in order to portray easy viewing and understanding  FIG. 7  primarily depicts the sun gear  22  disposedly engaging with the planetary gear set  230  of the triangular support  5 . The planetary gear set  230  first engages with the first annular gear  2 , wherein the first annular gear  2  is fixed to the housing  4  by means of the fixing members  21 , and thereby deemed to be in a fixed state thereof. 
   The satellite gears  23  outwardly extend to engage with and thereby rotate the second annular gear  3 . Upon the sun gear  22  rotating in a clockwise direction, the satellite gears  23  are actuated to rotate in a counterclockwise direction, and the triangular support  5  is simultaneously made to corotate in the same clockwise direction as the sun gear  22 . Rotational speed of the triangular support  5  multiplied by rotational speed of the satellite gears  23  therewith drives the second annular gear  3 , and forms a rotation in the same clockwise direction. Furthermore, the output shaft  30  extends outward from the second annular gear  3  (see  FIG. 6 ), thus forming a deceleration that magnifies torsion output and enables the angle-shaped transmission rod  31  to acquire high torsion transmission. 
   An external force feedback can also effectuate a brake effect. Referring to  FIG. 8 , if the second annular gear  3  is subjected to a return transmission active force F from the angle-shaped transmission rod  31  (see  FIG. 6 ), then the second annular gear  3  rotates and inwardly engages with the satellite gears  23 . Hence, upon the satellite gears  23  being necessarily subject to engaging, a turning power n is thereby generated, and gear teeth  231  at one end of the satellite gears  23  engage with the first annular gear  2 , under condition of the first annular gear  2  being fixedly configured to the housing  4 , then the turning power n is locked at a tangent p, which thereby disables the active force F from producing a displacement thereat. With the brake effect as described, the active force F effectuates the same locking effect whether rotation is clockwise or counterclockwise. Simply explained, under condition of the first annular gear  2  being fixed, the second annular gear  3  and the first annular gear  2  move in a relative motion, and If the second annular gear  3  actuates the inner satellite gears  23 , thereupon one end of the satellite gears  23  engage with the first annular gear  2 . However, because the first annular gear  2  is fixed, thus the satellite gears  23  are similarly fixed and unable to rotate, accordingly, the second annular gear  3  also is unable to rotate, hence a reverse locking effect is formed thereof. 
   Referring to  FIG. 9 , which shows a particular alteration of pitch circle of the second annular gear  3  of the present invention, and arrangement of the gears after alteration thereof. As depicted in  FIG. 9 , wherein the sun gear  22  engages with the satellite gears  23 , the satellite gears  23  being movable fixed within range of the triangular support  5 . 
   Radius of the sun gear  22  is R 1 , and radius of each of the satellite gears  23  is R 2 , thus, radius of the first annular gear  2  R=R 1 +R 2 . As depicted in  FIG. 9 , under condition of a fixed rotating speed of the sun gear  22 , working operation of the satellite gears  23  under the same corresponding condition similarly realizes a fixed rotating speed. 
   Another end of the satellite gears  23  engage with the second annular gear  3 , whereby pitch diameter of the second annular gear  3  is larger d 1  or smaller d 2  than pitch diameter of the first annular gear  2 , and pitch circle of the second annular gear  3  is configured to be relatively larger  3   a  or relatively smaller  3   b . On the basis that the circular pitch (cp) of mutual engaging of the gears is necessarily equal, otherwise interference will occur, and from the formula cp=πd/t, the present invention can by keeping m (where m=d/t) constant, and altering the number of teeth t, thereby cause the pitch diameter d to correspondingly change accordingly. Therefore, under condition of a fixed engaging axial rotational speed output by the satellite gears  23 , the second annular gear  3  having a relatively larger pitch diameter d is thereby abled to produce an even larger deceleration ratio, moreover, rotation of the second annular gear  3  and the sun gear  22  are decelerated in same direction. Furthermore, because the pitch diameter d of the second annular gear  3  is smaller, and with radius of the satellite gears  23  being fixed, a relatively high-speed rotational engagement is realized. Hence, size of pitch circumference (π×d) of the second annular gear  3  will affect varied alterations in rotational speed thereof. 
   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.