A HEIGHT CONTROL MECHANISM FOR A CHAIR, TABLE OR THE LIKE

Abstract: This is a device for fitting a control lever which is used to freely adjust the height of a pneumatic or hydraulic stay of a chair, table, etc. The control lever (15) presses down a push rod (10) for adjusting the height of the stay, is made of a single member, can be operated in either direction, upward or downward, can be easily fitted to the stay, and is reliably pre­ vented from slipping out. To allow the control lever to be operated in either direc­ tion, upward or downward, the control lever can be tilted, by selectively using, as a fulcrum, either of two openings (13a, 13b) or one opening and one step provided in a cylindrical wall member (11) constituting a part of the stay, according to the direction of operation. To allow the easy fitting of the control lever to the stay, the control lever is inserted through one opening and is pressed by the push rod to abut the upper edges of the openings or the step. To reliably prevent the control lever from slipping out, the control lever has engagement grooves or a groove (14) formed in the upper or lower surface of the control lever, to be en­ gaged with the openings or the push rod. Several embodiments are described.

Description: A device for fitting a control lever of a height adjustable stay The present invention relates to a device for fitting a control lever of a height adjustable stay. In more detail, it relates to a device for fitting a control lever of aheight adjustable stay damper as a part of a stay of, for example, a chair, table, etc., which is composed of a working fluid receiving the action of enclosed gas pressure, a cylinder slidably containing a piston positioned to separate the fluid into two chambers, and a piston rod connected at its one end with said piston and extending -flexibly at its other end from the end of the cylinder. Hitherto as observed in the gazette of UK Patent No. 1,514,188, with a chair or table equipped with such a height adjustable stay damper of gas pressure expansion type, the control lever for height adjustment of a stay damper is provided with a pivot hole at a specific point of the lever, and is fitted by a horizontal pivot put through the pivot hole onto a -bracket protruded from the stay damper or under the seat, etc. In this case, the control lever is restricted in the direction of fitting and it is necessary to insert a small pivot and to contrive a means for preventing the drop of the pivot. In addition to these troubles in fitting and removing the lever, since a pivot hole is formed in the lever, stress is concentrated at the lower or upper portion around the pivot hole, being liable to cause breaking. Apart from such fitting by use of a pivot hole and a pivot, as another fitting method for this kind of control lever, snap fitting method for says of chairs is known, for example, as disclosed in the gazette of UK Patent No. 1,510,028. In this case, a piston is slidably provided in a cylinder, and a communicating valve is provided in a hollow piston rod connected to the piston. The communicating valve is operated externally by control lever and a push rod. The push rod is connected with the control lever, with the tip of the push rod movably engaged with a given portion of the control lever, and in this case, a snap spherical surface, snap ring groove, etc. for allowing the tip of the push rod to be correctly engaged with is formed at the tip of the control lever, and the lever is inserted through a single opening provided in the piston rod, being held to allow upward tilting operation. Thus, difficult work is required for the structure of snap engagement, and since the control lever can be operated only in one direction as in case of the above mentioned pivotal fitting method, its fitting into a chair, etc. is inconvenient, and the operator finds it difficult to know the operating direction. If he operates the lever forcedly in the other direction, the lever may be bent or broken. The object of the present invention is to provide a device for fitting a control lever of a height adjustable stay damper suitable for stays of chairs, tables, etc. which, overcoming the above disadvantages of the conventional devices, can be operated upward and downward, fitted easily and prevented reliably from slipping out. To attain the above object, the present invention is characterized in that two openings or one opening and one step are formed to oppose each other on a straight line crossing the center of a push rod, in the wall of a cylindrical wall member constituting a part of a stay; a control lever is inserted across the two openings or the one opening and one step, is provided with engagement grooves or a groove to be engaged with the openings or the push rod, and is pressed by the push rod toward the upper edges of the openings or the step; and one of the two openings or one of the opening and the step is selectively used as a fulcrum according to the direction of operation, to allow tilting. Embodiments of the present invention are described below in reference to drawings. In the attached drawings, Fig. 1 is a partially cutaway longitudinal front view showing the device for fitting a control lever of a height adjustable stay damper as a preferable embodiment of the present invention. Fig. 2, 3, 4, 5, 6 and 7 are partially cutaway longitudinal front views showing the device for fitting a control lever of a height adjustable stay damper as other embodiments of the present invention. In describing the embodiments of the present invention, the internal structure and operation of the height adjustable stay damper itself for chairs, tables, etc. are not described here since they are the same- as disclosed, for example, in said gazette of UK Patent No. 1,514,188. In the present- invention, as shown in Fig. 1 as one example, a cylinder 9 is filled with a working fluid receiving the action of enclosed gas pressure, and a piston (not illustrated) slidably provided in the cylinder 9, to separate two working fluid chambers is connected with an end of a piston rod 10, the other end of the piston rod 10 being flexibly protruded upward from the end of the cylinder 9. At the tip of the piston rod 10, a thread portion 10a is formed, and on the other hand, a cup-shaped cylindrical wall member 11 to be fitted under a seat, table, etc. has a through hole for the piston rod and a thread portion lla formed at the center, being fitted detachably, as a part of the stay, with the piston rod 10 by screwing. A push rod 12 for operating a communicating valve of a communication passage of said piston section is inserted at the center of the piston rod 10, and the head of the push rod 12 is protruded from the end of the piston rod at the inside center of the cylindrical wall member 11. In the wall of said cylindrical wall member 11, opposing rectangular openings 13a and l3b are provided on a straight line with the push rod 12 at the center, and a control lever 15 is inserted detachably into these openings 13a and 13b -The control lever 15 has an engagement groove 14 in the lower surface, to be engaged with the head of the push rod 12, and is brought into contact with the upper edges of the openings 13a and 13b on the upper surface, to allow the control lever 15 to be tilted in either direction, upward or downward with either of the upper edges of the openings as a fulcrum 13a' or 13b'. For fitting the control lever 15, it is inserted from one of the openings-13a and 13b to the other, to press down the push rod 12 once by a taper surface 15a at the tip of the lever 15, and the push rod 12 returns at the position of the engagement groove 14 of the lever 15, to be engaged, not allowing t-he lever 15 to slip out. Furthermore, receiving the force of blocking force phase, etc. by the gas pressure of a communicating valve (not illustrated) or spring force to press the push rod 12 upward, the control lever 15 is pressed against the upper edges of the openings 13a and 13b, to simply complete the fitting of the control lever 15. In this state, the communication passage of the piston section is blocked by the communicating valve, and the stay damper is locked. If the control lever 15 is tilted upward in-X direction in the drawing, the lever tip is tilted to press down the push rod 12 with the upper edge of the opening 13a as the fulcrum 13a', to open the communicating valve of the piston section, allowing the communication of the working fluid between both the fluid chambers. Thus, by making the piston and the piston rod 10 slide, the seat, etc. can be adjusted to any given height, and if the control lever 15 is released, the seat, etc. can be locked and held at a desired position. Furthermore, when the control lever 15 is tilted downward in Y direction in the drawing, the lever presses down the push rod 12 with the upper edge of the opening 13b as the fulcrum 13b', and the seat, etc. can be adjusted to any desired given height. -Therefore, even if the control lever 15 is tilted in either direction, upward or downward, the push rod 12 can be pressed down, without causing any error of operation conveniently. 'The control lever 15 is prevented from slipping out, by the engagement between the head of the push rod 12 and the engagement groove 14, and if it is once fitted, it cannot slip out. Furthermore, by the raising force received by the push rod 12, the control lever 15 is pressed to the upper edges of both the openings 13a and 13b, to be kept firm. As for the pressing force of the.control valve 15 in the example of Fig. 1, if the communicating valve (not illustrated) of the piston section constituting the stay damper is of plunger valve type, the protruding force corresponding to the enclosed gas pressure acting on the effective pressure receiving area of the valve is transmitted through the push rod 12, and if the communicating valve of the piston section is energized by a stop spring, the protruding force corresponding to the stop spring is arranged to act as the pressing force for prevention of play. In any case, it is required that the. head of the push rod is brought into contact with the engagement groove 14 of the control lever 15 by the pressing force. Therefore, a coil spring 16 can be provided below the control lever 15 inside the cylindrical wall member 11 additionally to obtain the pressing force, and if the pressing spring 16 is provided additionally like this, dimension control becomes very easy. Furthermore in the example of Fig. 1, the cylindrical wall member 11 provided with the openings 13a and 13b to have the control lever 15 inserted through can be detached from the piston rod 10. Therefore when it becomes necessary to remove the lever for example for transporting the chair or for re-using the control lever 15 in the exchange of the stay damper itself, the thread portion lla of the cylindrical wall member 11 can be loosened, to release the engagement between the head of the push rod 12 and the engagement groove 14, to allow the control lever 15 to be pulled out easily. If there is no such necessity, the piston rod 10 can be formed to directly reach the position corresponding to the portion of said cylindrical wall member 11. Another embodiment of the present invention is described below in reference to Fig. 2. A cylinder 9 filled with a working fluid receiving the action of enclosed gas pressure contains a piston (not illustrated) slidably to separate two fluid chambers, and a piston rod 10 is connected at its one end to the piston, and protruded at the other end flexibly upward from the end of the cylinder. At the tip of the piston rod 10, a thread portion lla is formed, and at the center of a cup-shaped cylindrical wall member 17 to be fitted to a seat, a through hole for the piston rod and a thread portion 18 are formed. Through these thread portions lla and 18, the cylindrical wall member 17 is detachably fitted to the piston rod io. The thread portions Ila and 18 may be omitted, to fix the cylindrical wall member 17. On the other hand, a push rod 12 for operating a communicating valve for a communication passage of the piston section is inserted vertically movably at the center of the piston rod 10, and the upper end is protruded from the end of the piston rod at the inside center of said cylindrical wall member 17. Furthermore, in the wall of the cylindrical wall member 17, opposing openings 21 and 22 of rectangular, oval or oblong holes are provided on a straight line with the push rod 12 at the center, and a control lever 20 is inserted crosswise through these openings 21 and 22. The control lever 20 has two engagement grooves 19a and 19b in the upper surface, and is formed evenly flat on the lower surface, with a taper surface 21a formed at the lower portion of its tip. Said engagement grooves 19a and 19b are engaged with the upper edges of the openings 21 and 22, and the lower surface contacts the top of the push rod 12. Since the engagement grooves 19a and 19b are engaged with the upper edges of the openings 21 and 22,-the control lever 20 can be tilted in either direction, upward or downward with any of the upper edges of the openings as a fulcrum a or b. As in case of Fig. 1, if the depth of the engagement grooves 19a and l9b is Q2, and the clearance between the lower surface of the lever 20 and the lower edges of the openings 21 and 22 is Q1, then they are formed to satisfy Q1 > t2. The fitting of the control lever 20 is described below. When the lever 20 is inserted from one of the openings 21 and 22 to other, the push rod 12 is once pressed down by the taper surface 20a at the tip of the lever, and if the lever is pressed in further in this state, with the lower surface of the lever in contact with the push rod 12, the raising force of the push rod 12 makes the engagement grooves 19a-and 19b fit in the upper edges of the openings 21 and 22 when the engagement grooves 19a and 19b have come to the positions of the openings 21 and 22. Receiving the force of the blocking force phase, etc. of the gas pressure of the communicating valve (not illustrated) or spring force for raising the push rod 12, the engagement grooves 19a and 19b of the control lever are pressed against the upper edges of both the openings 21 and 22, not allowing the control lever to slip out. Thus, the fitting of the control lever 20 can be simply completed. In this state, the communication passage of the piston section is blocked by the communicating valve, and the stay damper is locked. Meanwhile, to remove the control lever 20 for the necessity of exchanging parts, etc., the control lever 20 can be pressed down against the push rod 12 within the range of R,, to release the engagement between the engagement grooves 19a and 19b and the upper edges of the openings 21 and 22, and in this state, it can be pulled rightward for example in Fig. 2, to be pulled out, with the lower surface and the taper surface 20a of the lever 20 sliding on the head of the push rod 12. Therefore, the control lever 20 can be freely and simply fitted and removed, to allow easy exchange, repair, etc. of parts. If the control lever is tilted upward in X direction in the drawing, the tip of the lever is tilted downward with the upper edge of the opening 22 as the fulcrum b, to press down the push rod 12, opening the communicating valve of the piston section, thereby allowing the communication of the working fluid between the fluid chambers. Therefore, by making the piston and the piston rod 10 slide, the seat, etc. can be adjusted to a given height. If the control lever 20 is released, the.seat, etc. canbe locked and held at a desired position. e Furthermore, if the control lever 26 is tilted downward in Y direction in the drawing, the rear end of the lever 20 is tilted downward, to press down the push rod 12, and the seat, etc. can be adjusted to a given desired height. As a further embodiment of the present invention, the control lever can be supported also by an engagement step formed instead of one of the openings. An example where the control lever is supported at one side by an engagement step is shown in Fig. 3. In Fig. 3, a cylinder filled with a working fluid receiving the action of enclosed gas pressure contains a piston (not illustrated) provided slidably to separate two fluid chambers, and a piston rod 25 is connected at its one end with the piston, and protruded at its other end flexibly upward from the end of the cylinder The tip of the piston rod 25 is connected with a cylindrical wall member 24 through a support member 23. In this case, the cylindrical wall member 24 may be a cylinder mounted with the piston rod 25, and the member indicated by symbol 25 may be a cylinder. In Fig. 3 where the member indicated by symbol 25 is used as a piston rod, and the member indicated by symbol 23, as a cylinder, a push rod 26 for operating a communicating valve for opening or closing the communication passage of the piston section is inserted at the center of the piston rod 25, and the upper end of the push rod 26 is protruded from the end of the piston rod 25 at the inside center of the cylindrical wall member 24. In the wall of the cylindrical wall member 24, an opening 27 of a rectangular, oval or oblong hole is provided to oppose a square engagement step 28, on a straight'line with the push rod 26 at the center. From said opening 27, the control lever 29 is inserted from its tip horizontally, and has its upper portion of the .tip held under the step 28. The control lever 29 has an engagement groove 30 formed in tge lower surface, and has a taper surface 31 at the lower surface at the tip, so that the control lever 29 can be smoothly inserted when the taper surface 31 contacts the head of the push rod 26 during the insertion of the control lever. And when the engagement groove 30 faces the push rod 26, the head of the push rod 26 fits in the engagement groove 30. If- the push rod 26 fits in the engagement groove 30, the control lever 29 is pressed upward, and the upper surface is pressed against the upper edge of the opening 27, and the end, against the step 28. With ether of the contact points as a fulcrum a or br the control lever 29 can be tilted in either direction, upward or downward. With regard to the operation, if the control lever 29 is tilted upward in X direction in the drawing, the tip of the lever is tilted downward with the upper edge of the opening 27 as the fulcrum a, to press down the push rod 26, opening the communicating valve of the piston section, thereby allowing the communication of the working fluid between both the fluid chambers. Therefore, by making the piston and the piston rod 25 slide, the seat, etc. can be adjusted to a given height, and if the control lever 29 is released, the seat, etc. can be locked and held at a desired position. Furthermore, if the control lever 29 is tilted downward in Y direction in the drawing, the rear end of the lever is tilted downward with the upper edge of the step 28 as the fulcrum b, to press down the push rod 26, and thus the seat, etc. can be adjusted to a desired given height. Therefore, even if the control lever 29 is tilted in either direction, upward or downward, the push rod 26 can be pressed down conveniently. The control lever 29 is prevented from slipping out, by the engagement between the push rod 26 and the engagement groove 30, and once it is fitted, it does not slip out during tilting operation. In addition, the raising force received by the push rod 26 presses the upper-surface of the control lever 29 against the upper edge of the opening 27 and the step 28, to keep engagement firm. The stay damper shown in Fig. 4 as a still further embodiment is substantially the same as that of Fig. 3, and is different only in the forms of the step and the cylindrical wall member. The upper portion of a cylindrical wall member 31 to be fitted to a seat or table is formed as a truncated cone by solid molding, and an inclined step 34 is provided between a conical portion 32 and a cylindrical portion 33, to make the inside wall of the inclined step 34 correspond to the step 28 of Fig. 3. The cylindrical portion 33 is mounted with a piston rod 36 through a thrust bearing 35, and a push rod 37 for operating the communicating valve is inserted vertically movably in the piston rod 36, to be protruded into the cylindrical wall member 31. The cylindrical wall member 31 is provided with an opening 38, and an inclined step 34 at a position tooppose the opening 38. The tip of a control lever 39 inserted from the opening 38 is engaged with the inclined step 34, and an engagement groove 40 provided in the lower surface of the control lever 39 is engaged with the push rod 37. With a spring 41 provided between the thrust bearing 35 and the control lever 39, the raising forces of the push rod 37 and the spring 41 press the control lever 39 at the upper portion at the tip and on the upper surface against the step 34 and the upper edge of the opening 38 respectively, to allow the contact points to be used as fulcrums a' and b'. If the control lever 39 is raised in X direction, the front of the control lever 39 is tilted around the fulcrum b1 to press down the push rod 37, and on the contrary if it is lowered in Y direction, the rear of the control lever 39 is tilted around the fulcrum a', to press down the push rod 37 similarly. The other effects are the same as described for Fig. 3. In the above embodiments, the control lever is fitted in the cylindrical wall member as a part of a cylinder or piston rod. However, in case of a stay damper in which a gas spring device itself is fitted in a stay consisting of an inside cylinder and an outside cylinder fitted mutually flexibly, the control lever can be tiltably fitted to the inside or outside cylinder of the stay. Figs. 5 and 6 show preferable embodiments with the control lever fitted to the inside cylinder of the stay damper. Detailed description is made below in reference to Fig. 5. An inside cylinder 44 is flexibly inserted in'an outside cylinder 51, to form a stay A. A thread portion 43 is provided at the upper end of a piston rod 42, and is screwed into the center of a holding plate 45 fixed by welding, etc. to the upper portion of the inside cylinder 44. By adjusting the amount of screwed engagement, the penetration of the piston rod 42 into the cylinder 46 can be selected as desired. Also at the upper portion of the inside cylinder 44, a pair of openings 47 and 47b are provided, to have a control lever 48 inserted through. The control lever 48 has an engagement groove 50 formed to be engaged with the head of the push rod 49, and in the state of engagement, the control lever 48-is normally resiliently pressed against the upper edges of the openings 47a and 47b, receiving the resilient force of the push rod 49 caused by gas reaction. In this state, if the control lever 48 is tilted upward in X direction in the drawing, the tip of the lever is tilted with the upper edge of the opening 47a as a fulcrum, to press down the push rod 50, opening the orifice of the piston, thereby allowing the communication of the working fluid between the fluid chambers. Therefore, by making the piston and the piston rod 42 slide, the seat, etc. can be adjusted to a given height. If the control lever 48 is released, the seat, etc. can be locked and held at a desired position. When the control lever 48 is tilted downward in Y direction in the drawing, the lever is tilted with the other opening 47b as the fulcrum, to press down the push rod 49, allowing the seat, etc. to be adjusted to a desired given height. In Fig. 6, the end of a piston rod 42 is not connected with a holding plate 52 by screwing, but held from both sides by snap rings 53, and a control lever 54 is inserted through openings 47a and 47b, while the engagement grooves 55a and 55b formed in the upper surface of the lever 54 are engaged with the upper edges of the openings 47a and 47b respectively. The lower surface of the control lever 54 is even, and the head of the push rod 50 contacts the even surface. An inside cylinder 44a can be straight as illustrated. Each of the inside cylinder 44a and the inside cylinder 44 of Fig. 5 has a seat or table mounted on it. Furthermore, the height adjustable stay damper itself is not limited to the type shown in the above examples. For example as shown in Fig. 7, a piston rod 60 can be protruded downward from a cylinder 61, and the head of a piston rod 60 interlocked with a valve 63 opening or closing a communication passage 62 in the cylinder can be protruded from the upper end of the cylinder 61, in an inverted vertical stay damper. In this case, opposing openings 65a and 65b to have the control lever 64 inserted through can be formed in a cylindrical wall member 61a as an extended portion on the upper end of the cylinder 61. The control lever 64 in the example of Fig. 7 is fitted and operated in the same way as described in the above examples. As described above, the present invention allows a control lever to be fitted in a stay damper by simple operation of inserting the control lever across two openings or one opening and one step opposing each other. Compared with the pivotal fitting method used hitherto, the present invention device is simple in structure and allows the lever to be fitted by general home users, etc., without resorting to skilled technicians. Therefore, when the device is delivered from the maker, it can be compactly packed with the control lever removed. Especially in case of the fitting device of the present invention, the control lever can be tilted in either direction, upward or downward. Even if the control lever is operated in either direction in this way, the cormunicating valve as a part of the stay damper can be released. Therefore, given a beginner can adjust the height of the seat, table, etc. with the stay damper instantly without thinking about the operating direction. In addition to this convenience, the control lever is not limited at all in the operating direction or fitting direction. In case of the conventional pivotally fitted control lever, the operator may operate the lever forcedly in the other direction by mistake, to bend or break the lever, but this disadvantage can be avoided. Thus, the present invention has various excellent effects. In addition, if the cylindrical wall portion with opposing openings provided in the present invention to have the control lever to be inserted through is made detachable from the piston rod with the push rod protruded, or from the end of the cylinder, the control lever can be easily removed even after it is fitted once, for exchange of the stay damper itself, for advantageous re-use of it for a new stay damper.

Claims: Claims. (1) A device for fitting a control lever of a height adjustable stay, in which a cylinder with at least a pressure liquid enclo & d and a piston rod flexibly inserted through a piston in the cylinder partially constitute a vertical stay for a chair, table, etc.; two fluid chambers are separated in the cylinder by the piston, and made to communicate or be isolated from each other by a communicating valve; and the communicating valve is driven by the external pressing of a push rod by the control lever, characterized in that a cylindrical wall member is formed as a part of the stay; two openings or an opening and a step are formed to oppose each other in the wall of the cylindrical wall member; and the control lever is inserted from one opening over the push rod to the other opening or the step, and is provided with an engagement groove or grooves to be engaged with the head of the push rod or the upper edges of the openings. (22 A device. for fitting a control lever of a height adjustable stay, as claimed in claim 1, wherein said cylindrical wall member is fitted at the upper end of piston rod, to be fitted under a chair, table, etc. (3) A device for fitting a control lever of a height adjustable stay, as claimed in claim 1, wherein said cylindrical wall member is a part of the piston rod. (4)'A device for fitting a control lever of a height adjustable stay, as claimed in claim 1, wherein said cylindrical wall member is a part of the cylinder with a pressure fluid enclosed. (5) A device for fitting a control lever of a height adjustable stay, as claimed in claim 1, wherein the stay is reinforced by an inside cylinder and an outside cylinder, with a part of the inside cylinder formed as said cylindrical wall member. (6) A device for fitting a control lever of a height adjustable stay, as claimed in claim 1, wherein two engagement grooves are formed in the upper surface of the control lever. ±7) A device for fitting a control lever of a height adjustable stay, as claimed in claim 1, wherein one engagement groove is formed in the lower surface of the control lever. ±8) A device for fitting a control lever of a height adjustable stay, as claimed in claim 1, wherein a spring for pressing the control lever upward is provided under the control lever. (9) A device for fitting a control lever of a height adjustable stay, as claimed in claim 1, wherein a taper surface is formed at the tip of the control lever. (10) A device for fitting a control lever of a height adjustable stay, as claimed in claim 1, wherein the vertical height of the opening is made larger than the vertical thickness of the control lever.

Inventors: NAKAMURA, KAZUO, OGISO, KAZUTOSHI
Applicants: KABUSHIKI KAISHA YANAGISAWA SEIKI SEISAKUSHO, KAYABA KOGYO KABUSHIKI KAISHA
Application year: 1981
Main classification: A47C3
IPC codes: A47B9, A47C3