Abstract:
A device for the manual operation of a blind, preferably a vertical blind, by way of a pull cord, which is pulled as a loop with a leading end and a return end by a slat carriage movable in a guide with a slat each arranged on them around their longitudinal axis. The device has a grip body that can be grasped, with a passage for the leading end and a passage for the return end of the pull cord. A clamping device is provided that can be switched from the outside for the leading end. A clamping device is also provided that can be switched from the outside for the return end (6b) of the pull cord (6).

Description:
FIELD OF THE INVENTION 
     The present invention pertains to a device for operating a blind, preferably a vertical blind, by means of a pull cord, the cord being led in a manner of a loop with a leading end and a return end and including a grip body that can be grasped, the grip body having a passage for the leading end and a passage for the return end of the pull cord. The gripping body includes a clamping means for clamping the leading end portion of the cord, the clamping means being switchable from an outside of the gripping body and including a clamping means for engaging the return end portion of the pull cord, the return end clamping means being switchable from the outside of the gripping body. 
     BACKGROUND OF THE INVENTION 
     Such a device has been known from U.S. Pat. No. 4,813,469. 
     In vertical blinds, the guide for the traveling movement consists of a usually horizontally fastened support rail, so that the ends of the pull cord, which also extends horizontally in the support rail in the area to be covered by the blind, run over a deflecting means and hang down loosely, and the pull cord frequently also forms a loop in this part and is thus designed as an endless pull cord. The hanging-down loop of the pull cord is frequently disturbing and represents a hazard, especially for small children. The blind can be opened and closed manually by means of a device of the class described in the introduction, while the slat carriages are either pushed together at a storage place or they are pulled apart, spread over the area to be covered by the blind. Large blinds and special designs have motor drives, preferably electric motor drives, for the pull cord. Horizontal blinds, in which the slats are fastened directly to two or more pull cords, which are arranged in parallel to and at spaced locations from one another, are also designed correspondingly. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to avoid hazards especially for small children due to the pull cord and to improve the appearance of the hanging-down pull cord. 
     According to the invention, a device for the manual operation of a blind is provided, preferably vertical blinds but also horizontal blinds. A pull cord is provided which is disposed in the manner of a loop and includes a leading end portion and a return end portion. A section rail is provided accommodating the pull cord leading end portion and the return end portion. The sectional rail has channels extending in a longitudinal direction defining passages for the leading end portion and the return end portion of the pull cord. A grip body is provided which can be grasped. The grip body includes a passage for the leading end portion of the pull cord and a passage for the return end portion of the pull cord. The grip body includes leading end clamping means for clamping the leading end portion of the pull cord. The leading end clamping means can be switched from the outside of the grip body. The grip body also includes return end clamping means for clamping the return end portion of the pull cord. The return end clamping means can also be switched from the outside of the grip body. The grip body is guided movably on the stationarily arranged section rail. 
     The sectional rail has channels extending in its longitudinal direction, through which the two ends of the pull cord, namely, the leading end and the return end, are led. These channels of the sectional rails, which may be open on the longitudinal sides, thus accommodate the ends of the pull cords in them, so that no pull cord is visible on the outside, and this pull cord also no longer represents a hazard of strangling for small children. A preferred embodiment of the sectional rail has an H-shaped cross-sectional profile with convex lateral surfaces. A deflecting means for a pull cord guided as an endless pull cord may be provided at the lower end of the sectional rail. However, a pull cord of finite length is also possible, so that the leading end and the return end move up and down in the corresponding channel of the sectional rail during the operation of the blind. 
     Another special feature of the present invention is that the switching slide, which is guided in the grip body at right angles to the longitudinal axis of the pull cord in such a way that it can be pushed to and fro. The switching slide has wedge surfaces on its underside, and each of these wedge surfaces cooperates with a counterwedge surface on a switching rod each. The switching rod pushes the corresponding clamping body due to the displacement of the switching slide in the grip body in order to push this clamping body from its clamped position that brings about the frictionally engaged coupling between the grip body and the corresponding end of the pull cord. The distance between the wedge surfaces on the switching slide in the direction of movement of the switching slide is greater than the distance between the counterwedge surfaces on the two switching rods in the same direction, so that only one of the two wedge surfaces can act at any one time on the corresponding counterwedge surface, in order to ensure that the other clamping body assumes the released position in the coupling position of one clamping body. The preferred design is one in which the wedge surfaces on the switching slide are arranged in a recess each, and this recess has a profile acting as an end position locking means for the two switching positions. 
     Finally, it is an advantage of the features of the invention explained above that the grip body may also have means to couple the grip body with a spindle shaft for pivoting the slats via pivoting gears in the slat carriages of a vertical blind. This is done, according to another idea of the present invention, by a spindle nut segment, which is movable in the grip body at right angles to the longitudinal axis of a spindle shaft led through the grip body, and which can be coupled with the spindle thread, in order to make possible a pivoting of the slats around their longitudinal axis in one direction or the other due to a movement of the grip body in the upward or downward direction. Another possibility of rotating the spindle shaft may be that the spindle shaft has a small hand wheel for its manual rotation, preferably at its lower end. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses,. reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a perspective view of a vertical blind; 
     FIG. 2 is a perspective view of a horizontal blind; 
     FIG. 3 is a vertical sectional view through the grip body along line III--III in FIG. 5 in a switching position A; 
     FIG. 4 is a sectional view corresponding to FIG. 3 in a switching position B; 
     FIG. 5 is a cross sectional view through the grip body along line V--V in FIG. 3; 
     FIG. 6 is a sectional view corresponding to FIG. 3, but with a modified clamping body; 
     FIG. 7 is a sectional view corresponding to FIG. 4, but with the modified clamping body; 
     FIG. 8 is a sectional view along line VIII--VIII in FIG. 6; 
     FIG. 9 is a vertical sectional view through a grip body with a drive means for a spindle shaft in a switching position D; 
     FIG. 10 is a sectional view corresponding to FIG. 9 in a switching position E; and 
     FIG. 11 is a vertical sectional view through a grip body with a drive for the spindle shaft, which drive is modified compared with FIGS. 9 and 10. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The vertical blind according to the exemplary embodiment in FIG. 1 has slats 23, which, hanging vertically next to each other, are arranged at spaced locations from one another, and whose top end is arranged, pivotable around the longitudinal axis of the slats 23, in a slat carriage, not recognizable from the drawing, wherein the slat carriages of all slats 23 are laterally displaceable in a support rail 22 that can be fastened horizontally. For this traveling movement, a pull cord, which runs over deflecting means at one end of the support rail 22 and is guided as an endless loop over a deflecting roller 19 at the lower end of a sectional rail 8, is guided through the slat carriage in a support rail 22, so that the pull cord passes through the grip body 21 of an operating device with a leading end 6a or leading section and with a return end 6b or return section. 
     The horizontal blind according to the example in FIG. 2 has horizontal slats 24, which are fastened hanging on a pull cord at spaced locations one on top of another. This cord can be wound on a shaft, which is mounted in a horizontally fastened support rail 22, and exits at one end of the support rail 22. A drive wheel 28, via which the pull cord 6 is laid in a vertically extending loop analogously to the example in FIG. 1, is fastened to this end of the shaft, so that it is guided over a deflecting roller 19 at the lower end of a stationarily arranged sectional rail 8, on which a grip body 21 of an operating device can be moved up and down and be optionally coupled with the leading end or the return end of the pull cord 6 due to frictional engagement. 
     According to the representation in FIGS. 3, 4 and 5, the grip body 21 is comprised of two grip body parts 1 and 2, whose division is located approximately in the vertical central plane. The two grip body parts 1 and 2 surround a vertically extending and stationarily arranged sectional rail 8, which has an H-shaped cross-sectional profile corresponding to FIG. 5. Thus, channels, into which the two pull cord ends 6a and 6b are placed, are formed on the two open sides of the H. The pull cord running over the deflecting roller 19 at the lower end of the sectional rail 8 is thus arranged hidden in the sectional rail 8, and it does not represent a hazard of strangling for small children. 
     In the exemplary embodiment according to FIGS. 3, 4 and 5, clamping bodies 4a and 4b made of clamp rollers placed loosely into the recesses are arranged in recesses of both grip body parts 1 and 2. They have a jacket surface that is corrugated or is made rough in another manner. The limiting walls of each of the two recesses cooperating with this jacket surface converge toward one another in the manner of a wedge, and one of these two limiting walls is arranged in an undercut, which is opposite the respective clamp roller 4a and 4b in relation to the pull cord 6 passing through the recess. In the case of a displacement of the grip body 21 in relation to the pull cord 6, firm coupling of the grip body 21 with the pull cord 6 can be achieved by frictional engagement by means of one of the two clamp rollers 4a or 4b. A switching rod 9a or 9b, which is movably guided in the grip body 21 approximately in parallel to the pull cord 6 and cooperates with wedge surfaces 26 or 27 on a switching slide 3, is associated with each clamping body 4a and 4b. The end of each switching rod 9a or 9b facing the switching slide 3 is provided with corresponding counterwedge surfaces. The wedge surfaces 26 and 27 are arranged in recesses of the switching slide 3 with opposite direction of inclination, so that a displacement of the switching rod 9a or of the switching rod 9b can be alternatively achieved by a displacement of the switching slide 3 in the grip body 21. In the example, a displacement of the switching slide 3 to the right brings about an axial displacement of the switching rod 9b in the downward direction, and a displacement of the switching slide 3 to the left brings about an axial displacement of the switching rod 9a in the downward direction. This axial displacement of the switching rods 9a and 9b takes place against the action of a spring 10. In the direction of displacement of the switching slide 3, the recesses with the wedge surfaces 26 and 27 are located at a distance from each other that is greater than the distance between the counterwedge surfaces on the switching rods 9a and 9b. It is achieved as a result that the switching rods can be operated only alternatively, so that a clamping connection is also possible only with one of the two pull cord ends 6a or 6b. The recesses with the wedge surfaces 26 and 27 of the switching slide 3 preferably have a profile, which also acts as an end position locking means for the two switching positions. To achieve an initial friction between the circumference of the clamp rollers 4a or 4b and the corresponding pull cord end 6a or 6b, spring-loaded pressing pieces 5a and 5b are arranged under the clamp rollers 4a and 4b, preferably in the direction toward the clamp rollers, and these pressing pieces 5a and 5b move the corresponding clamp roller 4a or 4b when the switching rod 9a or 9b is axially displaced by one of the springs 10 into a recess of the switching slide 3, in order to bring about a clamping coupling of the grip body 21 with the corresponding pull cord end. 
     The exemplary embodiment shown in FIGS. 6 through 8 corresponds to the description given for FIGS. 3 through 5, with the exception that the above-described clamp rollers 4a, 4b are replaced with respective clamping bodies 11a and 11b, which are arranged, pivotable around an axis extending at right angles to the pull cord, in the recess of the grip body 21. Further details become apparent from the graphic representation in FIGS. 6 and 7. 
     In the two exemplary embodiments according to FIGS. 3 through 5 as well as 6 through 8, a frictionally engaged coupling of the grip body 21 with one of the two pull cord ends 6a or 6b can be achieved by a horizontal movement of the switching slide 3 via the clamping means. The respective other pull cord end is released from its clamping coupling with the grip body 21 by an axial displacement of the switching rod 9a or 9b. 
     In the exemplary embodiment according to FIGS. 9 and 10, the clamping means for the frictionally engaged coupling of the grip body 21 with the pull cord ends 6a and 6b are designed corresponding to the description given for the examples shown in FIGS. 3 through 5 or possibly also the description for FIGS. 6 through 8. In addition, a spindle shaft 16 passes through a channel of the grip body 21. A spindle nut segment 15, whose threads can be pressed against the spindle thread by overcoming the force of a spring and can be engaged with same, is movably arranged in the grip body 21 radially to the longitudinal axis of the spindle shaft 16. A spring 18 is supported by the grip body 21, on the one hand, and by a collar edge of the spindle nut segment 15, on the other hand. A switching lever 14, which is mounted pivotably in the grip body 21, can be pivoted by the force of a finger via a pushbutton 13 projecting outwards, so that the threads of the spindle nut segment 15 and of the spindle shaft 16 become engaged, and the spindle shaft can be rotated in one direction or the other by a movement of the grip body 21 in the upward or downward direction, in order to pivot, e.g., the slats of a vertical blind in one direction or the other. FIG. 10 shows the engaged position of the threads of the spindle nut segment 15 and of the spindle shaft 16. FIG. 9 shows the resting position stabilized by the spring 28. Instead of the operating device for a spindle shaft 16 passing through the grip body 21, which was explained in connection with FIGS. 9 and 10, only a small hand wheel 17, whose knurls are arranged laterally from openings of a sectional cover cap 20 at the lower end of the sectional rail 8, is arranged for its operation according to the example in FIG. 11. The deflecting roller 19 for the pull cord 6 is arranged under this small hand wheel 17. The example in FIG. 10 clearly shows that the pull cord 6 and the sectional rail 8 do not have to be led up to the lower end of the blind in each case, but they may end at any height if it is accepted that the movement of the pull cord may take place in sections, possibly by grasping it again, using the mechanism accommodated in the grip body 21. 
     The example according to FIG. 11 also shows that the spring 7 loading the clamp rollers 4a and 4b is accommodated in a blind hole of the respective pressing piece 5a and 5b. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. 
     APPENDIX 
     LIST OF REFERENCE NUMBERS: 
     1 Grip body part 
     2 Grip body part 
     3 Switching slide 
     4 Clamping body 
     4a Clamp roller 
     4b Clamp roller 
     5a Pressing piece 
     5b Pressing piece 
     6 Pull cord 
     6a Leading end 
     6b Return end 
     7 Pressing piece spring 
     8 Sectional rail 
     9a Switching rod 
     9b Switching rod 
     10 Switching rod spring 
     11a Clamping body 
     11b Clamping body 
     13 Pushbutton 
     14 Switching lever 
     15 Spindle nut segment 
     16 Spindle shaft 
     17 Spindle shaft hand wheel 
     18 Spring 
     19 Deflecting roller 
     20 Sectional cover cap 
     21 Grip body 
     22 Support rail 
     23 Vertical slat 
     24 Horizontal slat 
     25 Wedge surface 
     26 Wedge surface 
     27 Drive wheel