Abstract:
A curtain blind take-up drive mechanism with non-slip effect having a freehand turn operation. The non-slip effect is configured to prevent slats of the blind from slipping down, and further includes coupling a power end of a drive shaft to a reel. The drive shaft connects to a worm gear via a transmission amplifier. The worm gear is actuated through reciprocally engaging with a worm driven via a flexible shaft coupling and through operation of a slat tilt rod. Reciprocal teeth meshing and teeth surface pressure between the worm gear and the worm achieves a high slip-rate, and thereby inhibits reverse transmission, thus accomplishing a reverse direction stoppage effect, and further producing a large frictional force and forming a surface-pressure slip effect thereof. The transmission amplifier allows the drive shaft to achieve a high rotational speed, thereby facilitating freehand operation for taking-up and letting-down of the slats.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     (a) Field of the Invention  
         [0002]     The present invention relates to curtain blinds, and more particularly to a curtain blind take-up drive mechanism with non-slip effect, providing freehand turn operation. The non-slip effect is further configured to prevent slats of the blind from slipping down under their own weight.  
         [0003]     (b) Description of the Prior Art  
         [0004]     Referring to  FIG. 1 , which shows a schematic view of a Venetian blind, including a head rail  1  lengthwise configured with a drive shaft  14  therein. A reel  15  is respectively attached to both right and left ends of the drive shaft  14 . A power end is actuated through any transmission of a turntable drive unit  12 . Indirect operation of a lift cord  130  actuates the reels  15 , and thereof reel cords  16  are enabled to take-up or let-down slats  11 . Upon a plurality of the salts  11  of a prior Venetian blind coming together, the slats  11  thereupon form a specific synergistic weight with proportional downward gravitational pull. The gravitational pull accordingly pulls on the reels  15  via the reel cords  16  causing the drive shaft  14  to reversibly rotate thereof, and the turntable drive unit  12  correspondingly begins idle running. Consequently the slats  11  slip down and open up.  
         [0005]     In order to counteract the aforementioned shortcomings, a conventional blind includes related positioning of components of the turntable drive unit  12 , and is additionally configured with resilient tensile components, and therewith utilizing a great variety of designs to achieve a non-slip stoppage component effect, such as resilience or unilaterality of a ratchet to clasp components, whereby a stoppage mechanism is formed. However, the aforesaid non-slip mechanisms are ineffective, for instance, resilience under certain conditions or undulations of indeterminate external forces will likewise cause the slats to slip downwards. Moreover, design of a unilateral ratchet clasp requires a frictional force to actuate a holding mechanism, and because cut-in angles or disparate strength of frictional forces, the frictional force often results in an idling situation arising. Recently, electric motor control has been employed, as well as utilizing electromagnetically controlled electromagnetic clutch methods to achieve a non-slip effect for a take-up and let-down locking control.  
         [0006]     The aforementioned non-slip mechanisms are especially suitable when applied to large-scale level slat style curtain units. More importantly, when wind power blows the blind slats, force of traction is produced, and dragging down of the slats results thereof. Furthermore, based on prior art design, whereby a lift cord  130  is employed to operate the take-up and let-down of the blind, the lift cord  130  is designed as a closed loop, whereby a lower section of the loop is a closed end, thereby forming a closed loop. The closed loop of the lift cord  130  can be dangerous to children, whereby when children are playing close to the lift cord  130 , the lift cord  130  can wind round the children&#39;s limbs and entangles the children thereof.  
       SUMMARY OF THE INVENTION  
       [0007]     Regarding the aforementioned shortcomings, a power end of a drive shaft  14  of the present invention is configured to utilize a gear meshing method between a worm  22  and a worm gear  21 , whereupon rotational speed is amplified through a transmission amplifier  4 , allowing a reel  15  to achieve an amplified rotational speed when taking-up the slats, and thereby facilitating freehand operation of a slat tilt rod  13 . A design objective of the present invention is to produce a return force actuated by teeth meshing and teeth surface pressure between the worm gear  21  and the worm  22 , and forming thereof a radial designated effect on the worm gear  21 , thereby achieving a non-slip effect, facilitating freehand operation and preventing danger from a lift cord of the prior art as described above.  
         [0008]     Another objective of the present invention is to configure the transmission amplifier to utilize a satellite gear unit, wherewith achieving transmission of a greater efficiency.  
         [0009]     A third objective of the present invention is to configure the transmission amplifier to utilize an inner-gear meshing configuration, which provides a design that is simple, easy and facilitating structurally change.  
         [0010]     A fourth objective of the present invention is to configure the transmission amplifier to utilize a combinatory configuration of meshing gears to facilitate selectivity in transmission variation.  
         [0011]     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  
       [0012]      FIG. 1  shows a schematic drawing of a Venetian blind of the prior art.  
         [0013]      FIG. 2  shows an elevational view of a preferred embodiment according to the present invention.  
         [0014]      FIG. 2-1  shows a cross sectional view of a preferred embodiment according to the present invention.  
         [0015]      FIG. 3  shows an elevational view of the drive shaft and reel mechanism according to the present invention.  
         [0016]      FIG. 4  shows a cutaway end view of the reel shaft according to the present invention.  
         [0017]      FIG. 5  shows an elevational view of another preferred embodiment according to the present invention.  
         [0018]      FIG. 6  shows an exploded elevational view of one configuration of the transmission amplifier according to the present invention.  
         [0019]      FIG. 7  shows a cross elevational view of another configuration of the transmission amplifier according to the present invention.  
         [0020]      FIG. 8  shows a cross elevational view of  FIG. 7  according to the present invention.  
         [0021]      FIG. 9  shows a cross elevational view of yet another configuration of the transmission amplifier according to the present invention.  
         [0022]      FIG. 10  shows a cross elevational view of  FIG. 9  according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]     Referring to  FIGS. 2 and 2 - 1 , which show a non-slip mechanism of the present invention comprising a worm gear unit  2  that avails the service of a transmission amplifier  4  to achieve high speed taking-up of slats  11 , and utilizes a high rotational slippage between a worm gear  21  and a worm  22  to actuate meshing of surfaces of gear teeth and thereof a reverse direction stoppage surface pressure, thereby producing a reverse direction stoppage effect, and achieving the objective of averting the slats  11  from slipping down under their own weight or from external forces.  
         [0024]     An operating end comprises a design employing a slat tilt rod  13 , the slat tilt rod  13  is adapted to accomplish a safety objective, whereby usage of a pull cord in prior art designs can result in entangling with limbs and thereof resulting in a dangerous situation arising.  
         [0025]     A primary configuration of the present invention comprises a drive shaft  14  configured lengthwise within a head rail  1 . The drive shaft  14  is freely secured in a support seat  6 , and a reversing wing  5  is further configured in the support seat  6 , with two extreme ends  51  and  52  of the reversing wing  5  separately connected to a T-cord  17 , and thereby adapted to have a drive-reversing-effect on the slats  11 .  
         [0026]     The T-cord  17  manipulates the slats  11 , thereby enabling adjustment of angle of tilt of the slats  11 , and regulating angle of light reflection thereof. The reversing wing  5  is mounted on an outer cylinder of a cord-retracting reel  15 , and adapted to having sliding friction effect, whereby the reversing wing  5  rotates in reciprocal relation to rotating of the reel  15 , and thereupon actuates the T-cord  17 , whereupon angle of tilt of the slats  11  are adjusted to regulate angle of light reflection. Upon completing adjustment of the slats  11 , if the reel  15  continues to rotate in the same direction (that is, the reel  15  proceeds to lift the slats  11  upwards), the reversing wing  5  will thereupon self-separate from the constricting frictional force of the outer cylinder of the reel  15 , allowing the reel  15  to free itself therefrom and freely rotate, and thus facilitate taking-up of the slats  11 . Design is of the prior art, and thus herein does not go into further details.  
         [0027]     A working end of a drive shaft  14  comprises a reel  15 , and the reel  15  is configured to be radially rotated. Furthermore, the reel  15  is rotatably positioned on a screw thread portion  61  defined on the support seat  6 , and an outer screw thread  153  screws onto the screw thread portion  61 . Upon the reel  15  rotating, because the reel  15  is screwed onto the support seat  6 , the reel  15  is transversely displaced along the support seat  6  (see  FIG. 2-1 ). If the reel  15  rotatably recedes in a right direction, it can be seen that operational displacement of the slats  11  results in letting-down of the slats  11 .  
         [0028]     A stop-push device  7  is configured on one section of the drive shaft  14  unit. The stop-push device  7  is secured within a mounting unit  71  disposed in the head rail  1  and connected with a standard coupling to a stop-push plate  72  of the drive shaft  14 , whereby the stop-push plate  72  receives cut-off pressure from the mounting unit  71 , thereupon ensuring the drive shaft  14  does not move lengthwise.  
         [0029]     The cord-retracting reel  15  provides winding and unwinding thereon of the reel cord  16  according to whether the slats  11  are being taken up or let down. A power end of the drive shaft  14  is actuated indirectly through the transmission amplifier  4  that connects to a drive shaft  20  and thereon coupling with the worm gear  21  of the worm gear unit  2 . The worm gear  21  meshes with teeth of the worm  22 , and the worm  22  is connected to a flexible shaft coupling  3 , and thereon lower down connects to a hand-operated slat tilt rod  13 , whereby the flexible shaft coupling  3  forms a universal polyhedral jointed transmission that facilitates the slat tilt cord  13  actuating the worm  22  from any relative angle thereof. Upon the worm  22  being actuated by the slat tilt cord  13 , meshing occurs between the worm  20  and the worm gear  21 , whereupon power from the worm gear  21  is transmitted to the coupling drive shaft  20  and thereon to the transmission amplifier  4 , whereupon functionality of amplifying rotational speed of the transmission amplifier  4  is employed to achieve an amplification of rotational speed of the driven drive shaft  14 , correspondingly providing the reel  15  the facility to hasten taking-up and letting-down of the slats  11 .  
         [0030]     Under a situation whereby the slats  11  have been taken up half-way or upon being completely taken up, because the slats  11  themselves possess a given weight, a slipping down effect under their own weight is produced, or because of influence from external forces, whereupon a pull-effect is affected on the reel cord  16  that is transmitted to the reel  15 , and produces rotation of the drive shaft  14 . After indirect transmission through the transmission amplifier  4 , a larger torque is produced that actuates rotation of the coupling drive shaft  20 , and the worm gear  21  connected to the coupling drive shaft  20  thereon meshes side-on with teeth of the worm  22 , and produces a teeth surface pressure stoppage effect from reciprocal meshing of teeth surfaces between the worm gear  21  and the worm  22 , achieving a non-slip effect therefrom.  
         [0031]     Referring to  FIGS. 3 and 4 , which show interactive relationships between the reel  15  and the drive shaft  14 . The reel  15  provides winding thereon of the reel cord  16 , a though hole  151  is adapted to affect radial meshing with the drive shaft  14 . Because vertical positioning of the reel cord  16  is fixed, thus in the process of taking up the slats  11 , the reel  15  and the drive shaft  14  form a lengthwise relative displacement, whereas movement positioning of the drive shaft  14  and the reel cord  16  are both fixed, and lengthwise displacement is produced by the reel  15 , therefore the through hole  151  is seen to make a lengthwise slip motion on the drive shaft  14 . In order to reduce friction between inside of the through hole  151  of the reel  15  and the drive shaft  14 , a cut-off block  140  is configured to engage between the drive shaft  14  and the through hole  151 , a slide piece  141  is radially configured on the cut-off block  140 , whereby the cut-off block  140  engages with the cut-off groove  152  defined within the through hole  151  of the reel  15 , and slippage between the slide piece  141  and the cut-off groove  152  operate in coordination to form a relatively small surface area friction, and radial support facilitates reducing radial frictional force when the reel  15  is rotating.  
         [0032]     Referring to  FIG. 5 , which shows an embodiment of the present invention, apart from a configuration of the transmission amplifier  4  as depicted in  FIG. 2 , the transmission amplifier  4  can further be configured between the worm  22  and the slat tilt rod  13  (see  FIG. 5 ). An upper portion of the slat tilt rod  13  is coupled to the flexible coupling shaft  3 , which thereon connects to the transmission amplifier  4 . A power end of the transmission amplifier  4  actuates the worm  22 , providing the worm  22  with an amplified rotational speed, and thereon meshing with the worm gear  21 . The transmission amplifier  4  is securely mounted directly below the head rail  1 . Because of the slats  11  rotating in a reverse direction under their own weight, teeth surface pressure between the worm gear  21  and the worm  22  correspondingly produce a stoppage effect of the slipping slats thereof.  
         [0033]     Referring to  FIG. 6 , which shows a structure of one embodiment of one application of the present invention. Basically,  FIG. 6  depicts application of a planetary gear set, whereby a central shaft gear  142  is connected to the drive shaft  14  and acts as a star gear. The central shaft gear  142  engages with satellite gears  42  by means of symmetrically angled meshing thereof. Furthermore, shaft pins  44  are configured on a turntable  43 , whereby the shaft pins  44  freely rotatably position the satellite gears  42 . The turntable  43  is connected to the coupling drive shaft  20 , and another end of the coupling drive shaft  20  connects to the worm gear  21 . Upon the worm gear  21  rotating, the worm gear  21  activates the turntable  43 , whereupon the shaft pins  44  engage peripherally with the satellite gears  42 , and the satellite gears  42  engage with an inner-ring gear  41 . During process of rotating meshing of gears, the central shaft gear  142  is actuated thereupon and rotates, whereupon meshing between the satellite gears  42  of smaller diameter and the inner-ring gear  41  of larger diameter affects a synergistic circumferential ratio effect, thereby producing an amplified rotational speed that meshes with the central shaft gear  142 , and thereupon is transferred to amplifying rotational speed of the drive shaft  14 .  
         [0034]     An objective of the present invention is advancement in simplification in accordance with structural requirements. As  FIGS. 7 and 8  show, the transmission amplifier  4  utilizes a method of bias meshing, whereby the central shaft gear  142  is configured to freely engage with the inner-ring gear  41 . The inner-ring gear  41  is coaxially connected to the coupling drive shaft  20 , which thereon connects to the worm gear  21 . Upon the worm gear  21  rotating, the inner-ring  41  is actuated, and inner teeth of the inner-ring gear  41  mesh with the central shaft gear  142 . Because diameter of the inner-ring gear  41  is larger than diameter of the central shaft gear  142 , rotational speed is amplified, and thereupon the transmission amplifier  4  amplifies rotational speed of the drive shaft  14 .  
         [0035]     The present invention facilitates installation placement of the worm  22  (see  FIG. 8 ) in longitudinal alignment with the drive shaft  14 . One side of the worm  22  meshes with the worm gear  21 , and the worm gear  21  is coupled to the coupling drive shaft  20 , which thereon connects to the inner-ring gear  41 . The inner-ring gear  41  is adapted to utilize a bias meshing method with the central shaft gear  142 , thereby allowing the drive shaft  14  and the worm  22  to be in longitudinal alignment.  
         [0036]     Referring to  FIG. 9 , which relates to the present invention achieving advancement in facilitating power requirements, convenience of preparing materials, and selectivity in rotational speed matching installation, whereby the present invention utilizes a simple and easy gear method that employs a multilayer gear configuration within the transmission amplifier  4 . The worm gear  21  at a power end of the transmission amplifier  4  is connected to the coupling drive shaft  20 , and thereof directly actuates a first gear  45 , the first gear  45  actuates a second gear  46 , the second gear  46  actuates a third gear  47 , and the third gear actuates a fourth gear  48 . Lastly, the larger fourth gear  48  engages with the central shaft gear  142 , thus forming a multiplying high power amplification, achieving amplification of rotational speed of the drive shaft  14 .  
         [0037]     Referring to  FIG. 10 , which shows another configuration to execute amplification of rotational speed. The worm gear  21  engages with the first gear  45 , whereon the first gear  45  directly meshes with a bridging gear  49 . A larger diameter of the bridging gear  49  meshes with the central shaft gear  142 , and amplification of rotational speed of the drive shaft  14  is similarly accomplished. Comparing  FIGS. 9 and 10 , amplification of rotational speed of  FIG. 10  is lower than that of  FIG. 9 . The lower rotational speed amplification can be utilized in a setting where a load the slats  11  have to bear is relatively light. Gear configuration of the transmission amplifier  4  in  FIG. 10  is such that amplification of rotational speed is produced simply from a unitary amplification executed through the bridging gear  49 . Whereas  FIG. 9  shows a configuration incorporating two additional gears including the second gear  46 , and the third gear  47 , achieving an enhancement in manyfold amplification of rotational speed. Configuration depicted in  FIG. 9  can be employed in a setting where a load the slats have to bear is relatively heavy.  
         [0038]     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.