MXPA96005605A - Mechanism of adjustment of height, hydraulic, parasi - Google Patents

Abstract

The present invention relates to an adjustable column assembly, the assembly is characterized in that it comprises: an external support tube having a lower end and an open upper end, a sub-assembly of column tube telescopically placed inside the tube External support, sub-assembly includes: an internal support tube, a cylinder inside the internal support tube, a piston inside the cylinder, a piston rod connected to the piston at one end and the external support tube at the other end so that the cylinder can move in and out of the external support tube on the piston, an elastomeric sleeve surrounding the cylinder, the sleeve and the cylinder define an expandable chamber having an inlet valve means between the cylinder and the inlet to the cylinder. expandable chamber to control the flow of fluid between the cylinder and the expandable chamber so that the flow velocity from the cylinder to the chamber is different from the velocity of flow from the chamber to the cylinder

Description

MECHANISM OF HEIGHT ADJUSTMENT, HYDRAULIC, FOR CHAIR BACKGROUND OF THE INVENTION The present invention relates to drive devices and, more particularly, to adjustment mechanisms useful as height adjusters in a variety of articles, including furniture. Various forms of drive devices. Telescopes are currently available to support and / or adjust the position of two different elements. In furniture applications, such drive devices are used with chairs, tables, work surfaces and the like. Currently available drive devices include hydraulic, pneumatic, pressurized gas or mechanical devices. In the seating area, the driving devices or support columns are used to fix the vertical height of the seat and adjust the seat for the user and / or task. Examples of mechanical drive devices can be found in the Patent North American No. 4,709,894 titled SLIDING CONNECTOR FOR WEIGHTED HEIGHT ADJUSTERS, which was granted on December 1, 1987, to Knobloc et al, and US Patent No. 5,234,187 entitled REF. MECHANISM: 23490 ADJUSTMENT OF HEIGHT FOR CHAIR, which was awarded on 10 October 1993, to Teppo et al. The adjusters of U.S. Patent No. 4,709,894 function when the seat is not occupied. The drive device is disengaged when the seat is occupied to allow the seat to rotate on the base without an effect on the seat height. The adjustment mechanism of US Patent No. 5,234,187 includes external, intermediate and telescopizing internal tubes and a mechanism that extends the telescoping tubes to adjust the height of the load. In one form, the mechanism includes a flexible, substantially non-elastic tape. Also included is a spring or piston / cylinder gas drive device for extending the tubes. Examples of pneumatic and hydraulic adjustment mechanisms or combinations of pneumatic / hydraulic adjustment mechanisms can be found in US Patent No. 3,381,926 entitled ADJUSTABLE TOOL, which was issued on May 7, 1968, to Fritz et al; US Patent No. 4,139,175 entitled "PEDESTAL OF CHAIR OR TABLE OF ADJUSTABLE HEIGHT", which was granted on February 13, 1979, to Bauer; US Patent No. 4,445,671 entitled SPRING OR GAS SPRING INCLUDING BLOCKING SYSTEMS, HYDRAULIC, which was granted on May 1, 1984, to Reuschenbach et al; and U.S. Patent No. 4,997,150 entitled ADJUSTABLE OLEOPNEUMATIC SUPPORT, which was issued on March 5, 1991 to Mardollo. Extendable adjustment mechanisms, especially those used in the furniture industry, need to be provided for varying loads, stability, shock absorbency, selected height adjustment, controlled movement, appropriate sliding ranges, rotating movement action of accommodation and being reliable with life of reasonable service. To achieve these desirable end results in existing existing systems, the commitment is not to have undue complexity or high costs. The gas actuators or previous tires operate at a relatively high pressure. The high gas operation and pressure characteristics result in leakage problems or sealing failures and complexity. Operating problems, including overvoltage adjustment have been experienced. The extension or retraction ranges are not controllable. The gas actuator devices require stops at the end of the slip or travel to provide protection to the mechanism and to avoid an abrupt shock or "lowering" for the user. In the seating area, it is also desirable to provide controlled shock absorbency. The shock-absorption characteristics of the pneumatic or gas actuator devices are poor. The damping characteristics of the gas are uncontrollable, which results in overvoltage and instability. Hydraulic systems can use a spring or gas spring or a spring or mechanical spring to dampen. The springs q mechanical springs suffer from overvoltage and instability. In addition, the spring may remain at the bottom, resulting in an excessive shock or shock to the user. Finally, it is desirable to provide a sufficiently wide range of displacement. For example, current regulations suggest that a chair should be adjustable from 16 inches to 20.5 inches above the floor. Such an interval is not always possible with the existing technology. There is a need for an improved drive device, which provides a long service life, improved reliability and improved operating characteristics at lower costs than those currently experienced.

BRIEF DESCRIPTION OF THE INVENTION In accordance with the present invention, the aforementioned needs are met. Essentially, an adjustment mechanism is provided, which includes a hydraulic drive device. The drive device has a cylinder, a piston, a piston rod and an expandable chamber. The interior of the cylinder is connected to the expandable chamber through a valve and a passage. With the valve open and under a conversion load, the piston moves towards the cylinder and the fluid is transferred from the cylinder to the expandable elastomeric chamber, where it is stored under pressure. When the valve is opened subsequently, the fluid is forced back into the cylinder, thus having the cylinder rod under the conditions "no load" or "low load". The valve provides different flow rates. The flow from the cylinder to the expandable chamber is restricted to a rate lower than the flow of the expandable chamber to the cylinder. As a result, the drive device extends more rapidly than it retracts. In further aspects of the invention, the piston and the piston rod assembly include a quick-attach interconnect. The piston functions as a true bearing that allows rotation or rotation of an article attached to the cylinder. The cylinder and the expandable chamber can be placed inside an internal support tube, which is telescoped inside an external support tube or base.

In other aspects of the invention, a shock absorber is provided. The users of conventional chairs expect a cushioning action, cushioning or springing when they sit down. In the preferred embodiment of the present invention, this expectation is satisfied by means of a shock absorber in the form of a compressible foam element placed in the cylinder. The adjustment mechanism according to the present invention is capable of providing a rapid, controlled, reduced speed extension and retraction to improve the operation when incorporated in a chair height adjustment mechanism. The system operates at reduced pressures compared to those previously experienced with pneumatic or gas drive devices. Higher reliability and lower failure rates are achieved. The mechanism is less complex than those devices provided so far. The mechanism is capable of providing more than 7 inches of travel and placing a seat 15 inches (or less) above the floor. The mechanism provides a smooth, quiet and reliable operation at a reasonable cost. Shock loads are easily absorbed. The mechanism easily adapts to or is incorporated into existing articles.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a chair incorporating an adjustment mechanism according to the present invention; Figure 2 is a cross-sectional, elongated view of the adjustment mechanism; Figure 3 is an elongated cross-sectional view of the adjustment mechanism of Figure 2, shown in the fully extended position; Figure 4 is an end view of an elastomeric sleeve incorporated in the present invention; Figure 5 is a cross-sectional view taken generally along line V-V of Figure 4; Figure 6 is a bottom, plan view of a valve assembly incorporated in the present invention; Figure 7 is a cross-sectional view taken generally along the line VTI-VTI of Figure 6; Figure 8 is a bottom plan view of a valve seat or channel element incorporated in the assembly of Figure 6; Figure 9 is a side elevational view of the channel element of Figure 8; Figure 10 is a cross-sectional view taken generally along line X-X of Figure 8; Figure 11 is a fragmentary, elongated, cross-sectional view of the drive device showing the valve assembly in the closed position; Figure 12 is a fragmentary, elongated, cross-sectional view of the actuator showing the valve in the open position with the actuator retracted; Figure 13 is a fragmentary, elongated, cross-sectional view of the actuator with the valve assembly in the open position with the actuator extending; Figure 14 is an end view of a piston and a piston rod assembly incorporated in the present invention; Figure 15 is a cross-sectional view, taken generally along line XV-XV of Figure 14; Figure 16 is a bottom, elongated view of the piston; Figure 17 is a cross-sectional view, taken generally along line XVII-XVII of Figure 16.

Figure 18 is a bottom view of a diaphragm assembly incorporated in an alternative valve structure according to the present invention; Figure 19 is a cross-sectional view taken generally along line XIX-XIX of Figure 18; Figure 20 is a fragmentary, elongated, cross-sectional view of the drive device showing the alternative valve structure in the closed position; Figure 21 is a fragmentary, elongated, cross-sectional view of the actuator showing the alternative valve in the open position with the actuator retracted; and Figure 22 is a fragmentary, elongated cross-sectional view of the drive device showing the alternative valve in the open position with the drive device extending.

DETAILED DECRIPTION OF THE PREFERRED MODALITY A chair incorporating a driving device or height adjustment mechanism according to the present invention is illustrated in Figure 1 and is designated generally by the number 10. The chair 10 is representative of one of many different articles that can incorporate the drive device. The chair includes a base or pedestal 12 supported on the pivoting sheaves 14. A height adjustment mechanism 16 is supported on the pedestal 12. The mechanism 16 is attached to a seat 18 through a chair control (not shown) . The seat backrest 20 is supported on the upper part of the driving device 16 through the control. As can be seen in Figures 2 and 3, the drive device 16 includes an external support spindle or tube 30, which telescopically receives a column tube assembly 32. The external support tube 30 includes an upper end 34 open and a lower end 36, closed. The tube 30 is preferably made of steel. A lower portion 38 of the support tube 30 tapers inward towards the lower part 36. The support tube 30 is configured to engage a coupling, self-locking taper on the pedestal 12. The tapering arrangement of the self-locking mechanism fixes the height adjustment for chair to pedestal. An elongated shell or bearing 42 snaps into the open end 34 of the support tube 30. The bearing 42 is preferably manufactured from a self-lubricating plastic material such as an acetal resin. The bearing allows telescopic axial rotational movement, free of column assembly 32 in and with respect to tube 30. Sub-assembly of telescopic column tube 32 includes the column or inner support tube 46, which is telescopically connected to the tube 30. The tube 46 includes an upper end 48, an upper tapered section 50 and an elongated section 52, the one terminating at a lower end 54. The tube 46, therefore, also includes a self-locking taper section similar to that of the outer tube 30 for attaching it to a chair seat or other element. The internal support tube 46 receives and accommodates a drive device generally designated 60. The drive device 60 includes a cylinder 62, a piston and a sub-assembly of piston rod 64, a valve subassembly 66. and a chamber structure or expandable sleeve 68. The inner cylinder 62 is an elongated, tubular member which is open at its upper end 72. The cylinder 62 and the tube 46 are closed at the lower ends 74, 54, respectively by means of a bushing a 76. As seen in Figures 2 and 3, the shell 76 defines a central tapered portion 78. The tapered portion 78 has an outer diameter engages and snaps into the lower end 74 of the cylinder 62. The taper 78 defines a through hole 80. The bushing 76 further includes a peripheral skirt, generally cylindrical, 82. The skirt 82 defines a slot 84. In the preferred embodiment, the expandable chamber structure 68 is an elongated, elastomeric sleeve, which has a generally cylindrical shape. A lower end 92 of the sleeve 68 is positioned in and captured by the slot 84 of the bushing 76. The lower end is attached to an outer surface of the cylinder 62 and to an inner surface of the skirt 82 of the bushing 76 by means of a suitable adhesive. The adhesive seals the end of the sleeve. The skirt or flange of the bushing and the cylinder provide a reinforcing compression seal. The sleeve is sized so that it must expand to fit over the cylinder 62. The sleeve expands and, consequently, under stress provides an initial preload force. This preload force should be sufficient to return the unoccupied chair to its highest position when the valve opens. An upper end 88 of the sleeve 68 defines a plurality of inlet passages 90. As seen in Figures 4 and 5, the inlet passages 90 are, in effect, grooves molded on an inner surface of the open end of the sleeve 68. slots 90 are communicated by the elongated, expanded slots 92, which extend longitudinally along the internal surface of the sleeve. The upper end 88 of the sleeve also includes an elongated or thickened wall section or band 96 having a tapered upper face 98 and a flat face 100. The wall section 96 is sized to engage the inner surface of the tubs * 46. thickened limits and prevents the expansion of passages 90 during operation. As seen in Figures 2 and 3, the outer surface of the sleeve 68 is sealed to an inner surface of the column support tube 46 at the upper end of the elongated section. A seal is provided by means of an adhesive as well as through the "compression" contact with the tapered inner surface or the shaped portion 48 of the support tube 46. The elastomeric material will deform when pressed to contact the surface inside the tube to form a seal. As seen in Figures 2 and 3, the support tube 46 and the inner cylinder 62 define an annular space between them, which receives the elastomeric sleeve 68. The inside of the sleeve communicates with a space or passage 106 between the cylinder and the column support tube at its upper ends through the inlet passages 90. The fluid entering the passages 90 under pressure will cause the sleeve to expand and be stored in the area of the expandable chamber under pressure. This will provide the energy to lift the chair unoccupied when the valve is open. As seen in Figure 5, it is heretofore preferred that the thickness of the wall of the sleeve 68 becomes thicker or tapered outwards, towards the end 84 from adjacent the adjacent face 100. The increase in wall thickness provides a variable force that helps transfer the fluid from the expandable chamber back to the cylinder during the extension of the actuator as described below. The sleeve is made of a rubber material that has sufficient strength and elasticity to generate the desired fluid return pressures and to withstand the operating pressures that will be experienced. Until now it is preferred that the sleeve be molded of a natural rubber compound not cured or vulcanized with a vulcanizer rich in sulfur (sulfur level of between 2.0 and 3.0 dpc) and charged with a carbon black rubber grade. The carbon black fluctuates in its particle size and structure between N330 and N550 with sufficient charge to achieve a tensile modulus of approximately 1400 to 1500 psi as measured by ASTM D-412 using a Dumbell die, C. The compound is cured or vulcanize using standard injection, transfer or compression molding technology. Operating pressures on a unit sized to handle a conventional office chair of the type shown in Figure 1 should be of the order of 100 psi with peak pressures of 200 to 600 psi statically. The piston and the piston rod assembly 64 include an elongated piston rod 112. The rod 112 has a slotted lower end 114 secured to the lower end 36 of the support tube 30 by means of a suitable jaw 116. A piston sub-assembly 118, as described in more detail below in connection with Figures 14-17, is attached to the upper end of the connecting rod 112. The connecting rod 112 extends through the central bore defined by the cap or cap 76. piston 118 gives an internal surface of cylinder 62 as a seal. To move from the fully extended position illustrated in Figure 3 to the fully retracted position of Figure 2, hydraulic fluid within cylinder 62 must be allowed to pass from inside the cylinder. through the passageway 106 and the inlets 90 towards the expandable chamber defined by the inner surface of the elastomeric sleeve 66 and the outer surface of the cylinder. The flow of fluid from between those two spaces is controlled by the valve subassembly 66. As shown in Figures 6-10, sub-assembly 66 includes a member or seat member 122 and a sub-assembly of diaphragm 124 which has a member. or internal shank 126. The seating element 122 defines a plurality of radially extending channels 128. As seen in Figures 6, 8, and 10, the channels 128 extend radially outwardly along a lower surface 130. and from a central opening or opening 132. The lower surface 130 defines a contact surface for a seat washer 138. The inner member or shank 126 is attached by means of a suitable adhesive to a rubber diaphragm 142. The diaphragm 142 is generally circular in the plan view and is placed in a seating area or cavity of the diaphragm 146. The cavity 146 includes a shaped lower surface 148, which helps to retain and position the diaphragm. ragma The rod 126 extends through the central bore 132 of the seating element. A valve element 152 is placed on the rod 126. The valve element 152 is fixed to the rod by the lower end 154. A floating element or washer 156 is placed around the rod 126 between the valve member 152 and the seat washer 138 The valve assembly 66 is retained at the upper end of the column tube sub-assembly, as illustrated in Figure 11. The upper end 162 of the cylinder 62 engages and sits against the seat washer 138. A suitable sealant adhesive or The elastomeric seal can be positioned within a groove 160 formed in the upper end 162. The seating element 122 is dimensioned to engage an inner surface of the support tube 46. The end 48 of the tube 46 is formed to retain the valve assembly and defines a centrally acting perforation 166. The diaphragm 124 forms a seal with the inner surface of the tube 46. The member 126 is closed by means of a sealing rivet 168. As seen in Figure 11, when the valve assembly 66 is in the closed position, communication between the inside of the cylinder 62 and the passage 106 is not allowed. The valve element 152 sits against the floating washer 154. The washer 154, in turn, sits against seat washer 138. Fluid can not flow through channels 128. Valve assembly 66 opens by pushing down on the central tapered area of diaphragm 124 in the inner member 126. The valve element 156 moves away from the floating washer 154. When a load is applied in the direction of the arrow A, as shown in Figure 12, to push the column 32 towards the external support tube from a In the expanded position, the hydraulic fluid within the cylinder will flow around the valve element 152 and through the annular passage defined by the washer 154 and the outer surface of the inner member 126. The flow rates are restricted to the maximum flow rate of the hydraulic fluid through the restricted hole. The inner support column 32 will retract or be pushed towards the outer support tube 30 in a controlled manner at a substantially constant rate with the increase in load. The fluid passing to the passageway 106 enters the inlets 90 of the elastomeric sleeve. The elastomeric sleeve will expand or expand radially outwardly around the tube or cylinder 62 to store the fluid under pressure. When the column 32 is in the desired partial or fully retracted position, the valve 66 closes releasing the pressure on the diaphragm. When it is desired to extend the column 32 and raise a chair seat or the like, the valve 66 opens again, as shown in Figure 3. The support tube 46 will extend in the direction of the arrow B. The fluid under pressure it is forced out of the expandable chamber by the elastomeric sleeve. Fluid will flow through passage 106, radial channels 128 and the annular space defined by seat washer 138 and internal member 126. As shown in Figure 13, floating washer 154 will now move away from the washer seat 138 under the influence of fluid flow. Therefore, a large orifice is provided for fluid flow from the elastomeric sleeve with the expandable chamber into the cylinder 62 instead of the opposite direction. The dimensions of the annular space defined by the seat washer 138 are greater than the dimensions of the annular space defined by the floating washer 154 »and the rod 126. With only the loading of the saddle seat 18 on the cylinder or with only a slight load above it, the cylinder will expand rapidly as the fluid under pressure is forced into the inner cylinder. When the desired position is reached, the diaphragm pressure is removed by closing the valve and blocking the column in position. The valve assembly, therefore, provides a directional flow rate, which varies from zero to a maximum in one direction and from zero to a greater maximum when the fluid flow is in the opposite direction. The speed of extension of the driving device is considerably faster than the speed of retraction. further, the speed for the retraction is almost constant with variable loads. The slower retraction speed gives the user sufficient reflection time to place the seat exactly at a desired height on the down stroke without overvoltage. The assembly also provides a smooth stop on the forward end without the need to add damping parts such as those found in gas or pneumatic actuators.The faster spreading speed allows the user to make quick, accurate adjustments, upwards since the chair seat follows and more rapidly and preferably maintains contact with the user when the user leaves it at the desired height The geometry of the radial passages 128 and the dimensions of the washers and the valve seat control the flow rates The channel seat element 122 can be made of an e-structural plastic, such as a nylon loaded with 6/6 glass.The diaphragm is made of rubber material.The inner member is attached to the diaphragm by The internal hollow member facilitates the filling of the inner cylinder with the hydraulic fluid, once the cylinder is filled, the member bro is permanently closed by means of a sealing rivet 168. The floating washer is preferably formed with a plastic material, which has sealing and lubricating properties such as Nylon 66 or a hard thermoplastic elastomer such as polyurethane. The seat washer and the valve element are made of steel. The piston and the piston rod sub-assembly 64 are shown in Figures 15, 16 and 17. As illustrated, the rod 112 is an elongated member, which defines a circumferential groove 180 spaced from an upper end 182. The piston 118 It has a configuration similar to a cross-sectional cup and includes an upper part 186 and a peripheral skirt 188. The piston 118 further defines an annular groove 190. As shown, an O-shaped seal or other suitable shape 192 is contained in the slot 190. The skirt 188 is formed with a plurality of slots 194 formed therethrough. The slots 194 open through the lower end 196 of the piston. The skirt also defines an outer peripheral ring 198 and an inner peripheral ring of flange 200. The piston 118 is molded of a suitable plastic material having flexibility and self-lubricating properties such as an acetal resin. A suitable material is an acetal resin sold by Dupont under the trade name Delrin 500. The piston and the piston rod assembly significantly increase the ease of assembly of the drive device and reduce the number of parts needed. The grooved slot or skirt allows the quick disconnection of the piston on the end of the connecting rod 112. The flange 200 is trapped in the retaining groove 180 formed on the connecting rod 112. The connecting rod 112, which is preferably made of a steel material 1018 in cold-finished bar is inserted into cylinder 62. Alternatively, connecting rod 112 could be made of reinforced designed resin such as glass-loaded polyester. When the piston is inside the cylinder, the ring 198 and the upper portion of the piston engage the inner surface of the cylinder to stabilize it. The seal 192 engages the inner surface to seal the hydraulic fluid in the cylindrical space above the piston head. The piston 118 functions as a true bearing which allows the collision assembly to rotate around the connecting rod 112. The piston is retained on the connecting rod since the portions of the skirt are restrained against outward movement by the inner surface of the cylinder. . The retaining edge 200 is held securely within the retention groove 180. Segmentation of the piston skirt wall allows for easy connection of the piston and connecting rod assembly. Since the segmented wall does not bend inside the cylinder, the piston is permanently captive on the piston rod. The piston can serve as a limit stop in the fully extended position, as shown in Figure 3. Since the piston functions as a true bearing, the saddle seat 18 can rotate around the connecting rod 112 through the piston. When the column support tube 46 rotates, the piston 118 is free to rotate with it. In addition, the cylinder 62 is free to slide on the piston, and consequently, oscillate towards and away from the external support tube 30. As shown in Figures 2 and 3, the cap 76 emerges as a braking guide or drum against the connecting rod 112 to help maintain concentricity. The external diameter of the flange or skirt 82 is elongated and engages the inner surface of the support tube 46. The skirt, therefore, keeps the cylinder centered with respect to the column tube 46. The lower surface of the cap 76, as shown in Figure 2, it also functions as a full or retracted limit stop as a true bearing when it comes in contact with the lower part of the external support tube or spindle 30. The driving device according to the present invention is designed to be used with an incompressible hydraulic fluid. It is preferred that the hydraulic fluid used be non-toxic and FDA approved, as well as non-tina and environmentally compatible. The fluid must be recyclable and operate at normal expected service temperatures from for offices such as chairs. The hydraulic fluid is substantially incompressible and, therefore, does not provide any damping characteristic when the valve is closed and the actuator is in the desired extended position. According to the present invention, the damping characteristics are provided by a damper or damping device 220. The damping element 220 is formed of a closed cell foam, which is resistant to permanent compression and permeability. The geometry and cell size of the foamed material can be designed to provide the desired damping characteristics. A load 8 that has been applied to the column 32 pressurizes the fluid in the cylinder 62, which compresses the shock absorber. Without the shock absorber, the incompressible nature of the fluid could prevent any movement, resulting in shock to the user. The use of a compressible foam material in conjunction with a substantially incompressible hydraulic fluid allows optimization of damping and energy dissipation characteristics. The damping can be selected so as to eliminate instability and overvoltage and at the same time provide sufficient damping to part of the displacement of the cylinder. The dissipation of energy could be an exponential function of the deflection, which could optimize the deceleration and avoid a hard or unpleasant stop or stop. It is heretofore preferred that the damping element 220 be molded as a generally cylindrical, elongated shape of a closed cell urethane foam. The foam can be formed with a film or urethane coating on the outer surface thereof to seal the element. The material hitherto preferred is a microcellular urethane with a density of 20 to 50 pounds per cubic foot. The foam damping element or supplier 220 overcomes the damping and overvoltage problems hitherto experienced with pneumatic or gas drive devices. Annoying settlement problems, experienced with mechanical dampers, such as chiral springs, are also eliminated. The drive device 16 according to the present invention of reliable operation. Operating pressures are significantly reduced from those experienced in pneumatic or gas drive devices. The integrity of the seal, reliability and service life are improved all.

This reduction achieved in complexity compared to previous drive devices also reduces costs and improves assembly and maintenance. An alternative valve structure according to the present invention is illustrated in Figures 18-22 and is designated generally by the number 266. The valve 266 includes a shaped diaphragm 268. The diaphragm 268, as with the previous embodiment, is attached to an internal member 270. The diaphragm 268 defines a central tapered section 272, a compression seal 274 and a skirt seal or outer peripheral lip 276. The diaphragm includes an internal annular passage 278 formed therein. The passage 278 communicates with an outer annular channel 284, which is on the other side of a flexible skirt 288. In order to retain the shape of the diaphragm 268, the stops 280 are formed in the diaphragm 268, which prevents any of channels 278, 284 are restricted during use. As seen in Figure 20, the diaphragm 268 is positioned on a seat member 290. The seat member is captured against the end 48 of the inner support tube 46 by the upper end of the inner cylinder 62. The portions of the diaphragm 274 , 276 form a seal with the end of the tube. A valve element 292 is secured to the end of the inner member 270. As with the above embodiment, the cylinder is evacuated and filled with the hydraulic fluid and then sealed with a suitable sealant rivet 294. When it is desired to move an extended column 32 up to In a retracted position, the valve opens and a load is applied to the central column. As seen in Figure 21, fluid flows from the inner cylinder 62 to the passage 106 moving around the valve member 292 through the passage 278 and along the skirt-288 to the annular channel 284. The skirt was restricted from bending outwardly by seat member 290 and, consequently, the flow of fluid to channel 284 is limited to that which is allowed by the space between the bottom skirt of skirt 288 and seat member 290, as shown by the arrows C in Figure 21. The restricted flow controls the retraction speed of the column towards the outer support tube. When it is desired to extend the element, the valve is opened as shown in Figure 22. The fluid under pressure of the energy sleeve passes in the direction of the arrows D through the passage 106 and into the radial channel 284. The skirt 288 it folds inwardly increasing the flow passage area and, consequently, increasing the flow velocity obtainable from the passage 106 towards the interior of the cylinder 62. Therefore a variable flow velocity is achieved, which is directionally dependent, with the valve assembly illustrated in Figures 18-22. The drive device according to the present invention is easily adaptable to furniture articles. The drive device provides a reliable height adjustment for a conventional chair, the tube or use of external support 30 is easily used with existing pedestal assemblies. The upper end of the column subassembly 32 easily attaches to the lower surface of a chair or chair control. The valve 66 can be operated in conventional manner with an external lever. The movement of the valve is linear. In a typical installation, an external lever could apply a driving motion to the sealing rivet or external surface of the valve. This movement could be controlled by the seated user, who applies a control force to a lever with a mechanical advantage in the range of 5-10: 1. An external force of 5 to 10 pounds could be desirable with a lever movement of approximately 1 inch. The diaphragm and control lever are preferably constructed so that the force required to open the valve increases with the increase in valve travel.

The assembly provides a speed of movement, which is easily controlled by the user. The assembly extends at a faster speed which is retracted for precise positioning and control in any direction. The valve assembly provides a positive seal to maintain the desired seat position under all expected conditions. The valve arrangement provides graduated or regulated fluid flow rate with the geometry of the orifice by determining the relationship between the degree of displacement of the valve and the fluid flow velocity. The movement of the chair is limited to safe values to the total displacement of the valve by the flow rate of fluid controlled by the orifice and the valve can be opened under any normal conditions. The valve arrangement provides a positive retention seal. The elastomeric sleeve is efficient due to its high energy density. The sleeve is selected to provide sufficient pressure or restoring force to the fluid to return an unoccupied seat to its uppermost position. The piston and piston rod configuration provides quick and easy assembly. The configuration ensures that the piston remains captured on the connecting rod and also allows the assembly to serve as a true rotational bearing. This eliminates the need for a separate element in the assembly. The damping characteristics can be designed to meet specific requirements through damper 220. Service life was increased over pneumatic or gas cylinders due, at least in part to the lower operating pressures and lubricating properties of the hydraulic fluid . Hydraulic fluid experiences normal static pressures of approximately 80 to 125 psi when compared to compressed gas drive devices, which "experience static pressures of more than 600 psi." Improved position control and sensation or movement are obtained through a submitted assembly since the speed can be modulated from fully closed to fully open by the user.Their retention and instability were eliminated visually.The loss of serviceability due to leakage was greatly reduced. greater reliability due to the lower number of parts, lower - precision required in its manufacture, fewer dynamic and static seals and lower operating pressures The structural and functional elements have been integrated into the drive device, thus reducing the number of parties significantly, a reduction of up to fifty percent in the number of parts on pneumatic actuators.

This results in a significantly lower cost to the total chair assembly as well. In view of the above description, those skilled in the art can devise various modifications which should not depart from the inventive concepts described herein. As a result, the above description could be considered not only that of the preferred embodiment. The actual spirit and scope of the present invention can be determined by reference to the appended claims. It is noted that in relation to this date, the best method known by the applicant to carry out the practice is the conventional one for the manufacture of the objects to which it refers. Having described the invention as above, property is claimed as contained in the following:

Claims (73)

RE- (VINDICATIONS

1. An adjustable column assembly, the assembly 'is characterized in that it comprises: an external support tube having a lower end and an upper, open end; a sub-assembly of column tube placed telescopically within the external support tube, the sub-assembly includes: an internal support tube or a cylinder inside the internal support tube; a piston inside the cylinder; a piston rod connected to the piston at one end and the external support tube at another end so that the cylinder can move in and out of the external support tube on the piston; an elastomeric sleeve surrounding the cylinder, the sleeve and the cylinder define an expandable chamber having an inlet; valve means between the cylinder and the inlet to the expandable chamber to control the flow of fluid between the cylinder and the expandable chamber so that the flow velocity from the cylinder to the chamber is different from the flow velocity from the chamber to the cylinder .

2. An adjustable cylinder assembly according to claim 1, characterized in that the elastomeric sleeve is generally cylindrical in shape and has an end which defines the inlet with the cylinder.

3. An adjustable cylinder assembly according to claim 2, characterized in that the sleeve has a wall having a tapered cross-section.

4. An adjustable cylinder assembly according to claim 3, characterized in that the outer surface of the sleeve at its inlet end is in sealed contact with the inner surface of the internal support tube.

5. The adjustable cylinder assembly according to claim 4, characterized in that the sub-assembly of column tube further includes a bushing attached to the cylinder, the bushing defining a control spindle surrounding the piston rod.

6. The adjustable cylinder assembly according to claim 5, characterized in that the bushing further defines an outer skirt, and the skirt and spindle define a slot, the sleeve and the cylinder are positioned within such slot.

7. The adjustable cylinder assembly according to claim 1, characterized in that it also includes a cushioning, compressible element placed inside the cylinder.

8. The adjustable cylinder assembly according to claim 7, characterized in that the damping element is a closed cell foam element.

9. The adjustable cylinder assembly according to claim 1, characterized in that the piston rod defines a circular groove adjacent to one end.

10. The adjustable cylinder assembly according to claim 9, characterized in that the piston includes a segmented skirt defining a plurality of skirt portions separated by grooves.

11. The adjustable cylinder assembly according to claim 10, characterized in that each of the skirt portions define a ridge on. an inner surface thereof, the ridges are configured to be received by the circular groove, so that the piston can be trapped on one end of the piston rod, and the piston and connecting rod can then be inserted into and captured by the piston rod. cylinder.

12. The adjustable cylinder assembly according to claim 11, characterized in that the piston rotates on the piston rod.

13. The adjustable cylinder assembly according to claim 12, characterized in that the skirt defines an annular groove and the assembly further includes an O-shaped ring within the annular groove.

14. The adjustable cylinder assembly according to claim 6, characterized in that the piston rod defines a circular groove adjacent to one end.

15. The adjustable cylinder assembly according to claim 14, characterized in that the piston includes a segmented skirt defining a plurality of skirt portions separated by grooves.

16. The adjustable cylinder assembly according to claim 15, characterized in that each of the skirt portions defines a ridge on an internal surface thereof, the rims are configured to be received by the circular groove so that the piston can be locked on the end of the piston rod, and the piston and connecting rod can then be inserted into and captured by the cylinder.

17. The adjustable cylinder assembly according to claim 16, characterized in that the piston rotates on the piston rod.

18. The adjustable cylinder assembly according to claim 17, characterized in that the skirt defines an annular groove and the assembly further indicates an O-shaped ring within the groove.

19. The adjustable cylinder assembly according to claim 18, characterized in that it also includes a compressible cellular foam element placed inside the cylinder.

20. The adjustable cylinder assembly according to claim 1, characterized in that the valve means comprises: a valve seat member defining a valve bore, a valve seat and at least one passage connected to the bore; a valve diaphragm on the valve seat member; and a valve element connected by the valve diagram and that can be moved by the diaphragm away from and against the valve seat.

21. The adjustable cylinder assembly according to claim 20, characterized in that the valve means further comprises a floating element between the valve element and the valve seat, the floating element restricts the flow of the cylinder through the passage to the expandable chamber and moves away from the valve seat to allow flow to increase in the opposite direction.

22. The adjustable cylinder assembly according to claim 21, characterized in that the valve seat member defines a plurality of radially extending passages.

23. The adjustable cylinder assembly according to claim 22, characterized in that the valve element comprises a rod member attached to the diaphragm.

24. The adjustable cylinder assembly according to claim 23, characterized in that the piston rod defines a circular groove adjacent to one end.

25. The adjustable cylinder assembly according to claim 24, characterized in that the piston includes a segmented skirt defining a plurality of skirt portions separated by grooves.

26. The adjustable cylinder assembly according to claim 25, characterized in that each of the skirt portions define a flange on an internal surface thereof, the flanges are configured to be received by the circular groove so that the piston can be trapped on one end of the piston rod, and the piston and connecting rod can then be inserted into and captured by the cylinder.

27. The adjustable cylinder assembly according to claim 26, characterized in that the piston rotates on the piston rod.

28. The adjustable cylinder assembly according to claim 27, characterized in that the skirt defines an annular groove and the assembly further includes an O-shaped ring within the annular groove.

29. The adjustable cylinder assembly according to claim 21, characterized in that the elastomeric sleeve is of generally cylindrical shape and has one end, which has at least one slot to define the entrance with the cylinder.

30. The adjustable cylinder assembly according to claim 29, characterized in that the sub-assembly of column tube further includes a bushing attached to the cylinder, the bushing defining a central spindle surrounding the piston rod.

31. The adjustable cylinder assembly according to claim 30, characterized in that the bushing further defines an outer skirt, the outer skirt and the spindle define a slot, the sleeve and the cylinder are positioned within the slot.

32. The adjustable cylinder assembly according to claim 20, characterized in that the diaphragm defines a flexible skirt positioned within the passage, the skirt restricts flow through the passage in one direction but flexes to allow the flow to increase in the opposite direction.

33. The adjustable cylinder assembly according to claim 32, characterized in that the diaphragm further defines a compression seal positioned between the valve seat member and the internal support tube.

34. The adjustable cylinder assembly according to claim 33, characterized in that the diaphragm further defines a peripheral lip which engages an internal surface of the internal support tube.

35. A height adjustment device for raising, lowering and locking a chair seat and the like in a position with respect to a base, the device is characterized in that it comprises: a support tube; a cylinder placed inside the support tube, the tube and the cylinder define an annular space; a piston placed inside the cylinder; a connecting rod connected to the piston at one end and extending from the cylinder, the piston and the cylinder can rotate on the connecting rod; an expandable chamber within the annular space to receive and pressurize a fluid; means of passage between the cylinder and the chamber to define a passage and allow the flow of fluid between the cylinder and the chamber when the piston moves inside the cylinder; and flow control means within the passage to control the flow of fluid between the cylinder and the expandable chamber, the flow control means allow flow between the cylinder and the chamber at different speeds depending on the direction of flow.

36. A height adjustment device according to claim 35, characterized in that it further includes an external support tube having an open end and a closed end, the support tube is placed inside the external support tube.

37. The height adjustment device according to claim 35, characterized in that the expandable chamber comprises an elastomeric sleeve within the annular space surrounding the cylinder.

38. The height adjustment device according to claim 37, characterized in that the elastomeric sleeve defines an entry opening in the annular space, the passage means connecting the inlet with the cylinder.

39. The height adjustment device according to claim 38, characterized in that the flow control means comprise a valve positioned within the passage, the valve includes a valve seat member defining a bore, a seat and a valve passage. , a diaphragm on the valve seat member and a valve member connected by the diaphragm, so that movement of the diaphragm moves the valve member away from the valve seat allowing fluid flow between the cylinder and the expandable chamber.

40. The height adjusting device according to claim 39, characterized in that the valve further includes flow restricting means for restricting the flow of the cylinder to the expandable chamber.

41. The height adjustment device according to claim 40, characterized in that the valve includes a rod element extending from the diaphragm and wherein the valve element is fixed to the rod element.

42. The height adjusting device according to claim 41, characterized in that the flow restriction means comprise a floating element shown displaceably on the rod element between the seat and valve element.

43. The height adjustment device in accordance with the. claim 41, characterized in that the flow restriction means comprise a flexible skirt "" connected to the diaphragm located within the passage of the valve.

44. The height adjustment device according to claim 40, characterized in that it also comprises a compressible damper placed inside the cylinder.

45. The height adjustment device according to claim 44, characterized in that the damper is an expanded foam element.

46. The height adjustment device according to claim 35, characterized in that 15 the piston rod defines a circular groove adjacent to the end, the piston is generally similar in shape to a cup in cross section and has an expandable skirt defining a flange positioned within the groove so that the piston can be pushed over the piston. crank 20 continued inserted in the cylinder.

47. The height adjustment device according to claim 46, characterized in that the piston skirt defines a plurality of grooves. 25

48. The height adjustment device according to claim 47, characterized in that it comprises a bushing placed at one end of the cylinder and defines a connecting rod bore, the connecting rod extends through such a connecting rod bore.

49. The height adjustment device according to claim 48, characterized in that the expandable chamber comprises an elastomeric, elongated sleeve, which surrounds the cylinder, inside a first end defining an inlet and a second sealed end.

50. The height adjusting device according to claim 49, characterized in that a portion of the sleeve at the end has a thicker cross-section and an angled face.

51. The height adjustment device according to claim 50, characterized in that the support tube engages the sleeve in the thickest cross section.

52. The height adjustment device according to claim 51, characterized in that the sleeve has a wall thickness tapering out from the thicker cross-sectional portion towards the sealed end.

53. The height adjustment device according to claim 52, characterized in that it further includes an external support tube having an open end and a closed end, the support tube is placed inside the external support tube.

54. The height adjustment device according to claim 53, characterized in that the flow control means comprise a valve positioned within the passage, the valve includes a valve seat member defining a bore, a seat and a valve passage. , a diaphragm on the valve seat member and a valve member connected by the diaphragm, so that movement of the diaphragm moves the valve member away from the valve seat allowing fluid flow between the cylinder and the expandable chamber.

55. The height adjusting device according to claim 54, characterized in that it further comprises a compressible element placed inside the cylinder and that is compressed by the increasing fluid pressures inside the cylinder.

56. The height adjusting device according to claim 54, characterized in that the valve further includes flow restricting means for restricting the flow of the cylinder to the expandable chamber.

57. The height adjustment device according to claim 56, characterized in that the valve includes a rod element extending from the diaphragm and wherein the valve element is fixed to the rod element.

58. The height adjustment device according to claim 57, characterized in that the flow restriction means comprise a floating member movably mounted on the rod element between the seat and the valve element.

59. The height adjustment device according to claim 40, characterized in that the flow restriction means comprise a flexible skirt attached to the diaphragm and positioned within the passage of the valve.

60. The height adjustment device according to claim 59, characterized in that it further comprises a foam cushion placed inside the cylinder.

61. A hydraulic drive device, characterized in that it comprises: a cylinder having a first end and a second end; a closure placed inside the second end, the closure defines a connecting rod hole; a connecting rod extending towards the cylinder through the connecting rod bore; a piston on the connecting rod, the piston is inside the cylinder; an elastomeric, expandable sleeve, surrounding the cylinder, the sleeve defines an inlet; a passage that connects the entrance of the sleeve with the cylinder; and valve means within the passage for controlling the flow of a hydraulic fluid from the cylinder to the inlet of the sleeve, the valve means can move from a closed position to an open position and allow the flow of the cylinder at the inlet of the sleeve to a speed less than the flow velocity from the sleeve inlet to the cylinder.

62. The hydraulic drive device according to claim 61, characterized in that it further comprises a compressible member within the cylinder between the piston and the valve means.

63. The hydraulic drive device according to claim 61, characterized in that the piston is cup-shaped in cross-section and defines a skirt having an inner rim.

64. The hydraulic drive device according to claim 63, characterized in that the piston rod defines a groove which receives the flange.

65. The hydraulic drive device according to claim 64, characterized in that the skirt is segmented and the piston is sufficiently flexible to allow the flange to expand over the end of the connecting rod and then be received in the groove.

66. The hydraulic drive device according to claim 65, characterized in that it comprises a compressible member inside the cylinder, which can be compressed by the hydraulic fluid inside the cylinder when the valve is closed and the rod is pushed towards the cylinder.

67. A piston / cylinder drive device, characterized in that it comprises: an elongate cylinder; a bushing placed at one end of the cylinder, the bushing defines a central bore; an elongate rod extending through the bore and towards the cylinder, the connecting rod defines a circumferential groove adjacent one end thereof within the cylinder; and a piston, the piston has an expandable skirt and a retaining flange thereon, the piston fits over the connecting rod with the flange positioned in the groove and the piston remains captive on the connecting rod by contact with the internal surface of the cylinder.

68. The drive device according to claim 67, characterized in that the skirt defines a plurality of slots separating the skirt into segments.

69. The drive device according to claim 68, characterized in that it further includes a guide ring on the skirt adjacent to a lower end thereof.

70. The drive device according to claim 69, characterized in that the piston defines an annular groove and the drive device further includes an O-shaped annular seal within the groove.

71. A hydraulic drive device, characterized in that it comprises: a cylinder including incompressible fluid therein; a piston placed inside the cylinder; a connecting rod connected to the piston; a valve on the cylinder to control the flow of incompressible fluid in and out of the cylinder; and a compressible damper placed inside the cylinder and immersed in the incompressible fluid so that the incompressible fluid compresses the compressible absorber volumetrically when the incompressible fluid is loaded.

72. The hydraulic drive device according to claim 71, characterized in that the damper is an expanded foam element. * r-

73. An adjustable column assembly for a chair or the like, characterized in that it comprises: an external support tube having an open end; and a sub-assembly of column tube telescopically positioned within the external support tube, the subassembly is adapted to move inwardly and outwardly of the external support tube, the sub-assembly includes: an internal support tube; a cylinder inside the internal support tube; a piston inside the cylinder; a piston rod connected to the piston at one end so that the cylinder can move in and out of the external support tube on the piston; an elastomeric sleeve surrounding the cylinder, the sleeve and the cylinder define an expandable chamber having an inlet, the sleeve having a preload force capable of extending the cylinder to its most external position when the chair is not occupied; and valve means between the cylinder and the inlet to the expandable chamber to control the flow of fluid between the cylinder and the expandable chamber.