FR2699256A1 - Telescopic auto-locking support for load - comprises chamber joined to reservoir of fluid by pipe equipped with interruption part movable between open, closed positions which allows communication - Google Patents

Abstract

The support comprises a jack body (1) in which a piston (2) is mounted slidably and defines a chamber (3) of variable volume. One of the elements is fixed to the load and the other is also fixed. The chamber (3) is joined to a reservoir (5) of fluid by a pipe (4) equipped with an interruption part (7) movable between an open and closed position and when open establishes communication of the chamber (3) with the reservoir (5). The movable part overcomes two conflicting forces, in open and closed positions. USE/ADVANTAGE - Allows adjustment to keep load level. Load tables.

Description

The present invention relates to a remote support

  self-locking copic for easy adjustment of the

charge maintenance level.

  Many devices implement sup-

  telescopic ports to adjust or modify the level of an object This is particularly the case in furniture, height-adjustable seats, tables with adjustable level There are many mechanisms to ensure movement, adjustment and locking at desired level of the object; some of them include a telescopic column with means for moving one of the elements which is integral with the load relative to the other element which is generally equipped with a base These means are of the pneumatic or screw jack type in particular for seats Whether screw or pneumatic cylinders, these devices include manually actuated members either to generate movement or

  to actuate a locking member.

  By the present invention, there is provided a dis-

  positive like telescopic support to support a

  load (which can be a table, a seat or any other mobi-

  house or office link) in which the lock

  load position at the selected level is obtained automatically

  matically, by relinquishing it, without having

  use of operating or locking means.

  More specifically, the subject of the invention is a sup-

  self-locking telescopic port for a load, including

  nant a cylinder body, in which a piston is mounted to slide watertight and defines a variable volume chamber, one of the body-piston elements being integral with the load, the other being fixed According to the main characteristic of the invention , the chamber is connected to a fluid reservoir by a conduit fitted with a movable interruption member between an open position and a closed position

  of the duct, the open position establishing communication

  cation of the chamber with the reservoir through a calibrated section, the movable member being subjected to two opposing forces, one returning to its open position,

  the other return to its closed position, the latter

  nière being generated by the pressure prevailing in the variable volume chamber, the return force at opening being less than the return force at closure generated by the pressure prevailing in the chamber under the effect of the total weight

  of the load whatever the position of the shutter member

ration.

  In a first embodiment, the information organ

  terruption consists of a distributor drawer, one end of which is subjected to the effect of a return spring in its open position and the other end of which is

  subject to the effect of the pressure of the variable volume chamber

  ble, recalling the drawer to its closed position.

  Preferably, the calibrated section is mena-

  However, it can be placed anywhere on the duct connecting the chamber to the tank.

  In a second embodiment, the shutter member

  ration is a movable valve relative to a fixed seat and

  the calibrated section is constituted by the flow section-

  ment of the fluid delimited by the seat and the valve in the

opening position of the latter.

  Preferably, the valve is carried by the piston, the reservoir being constituted by the enclosure part

located above the piston.

  In a simple variant, the valve is a body

  weight and the return force of the valve in its open position

  verture is formed by the attraction of gravity (less the buoyancy, especially when the

fluid is a liquid).

  In another variant, the valve consists of an elastic blade forming a shutter for an orifice of the

  piston, normally spaced from this hole.

  Preferably, the chamber and the reservoir are formed in the cylinder body on either side of the

  pistnn, the latter being equipped with the calibrated conduit and the

  interruption gane and being carried by a through rod extending in the chamber and in the tank.

  Other characteristics and advantages of the invention

  tion will emerge from the description given below of more

some examples of realizations.

  Reference will be made to the appended drawings in which: C FIG. 1 is a diagram of a first embodiment of the invention, FIG. 2 is a variant of FIG. 1,

  FIG. 3 illustrates a second embodiment

  tion of the invention, Figures 4 and 5 are schematic views

  partial of first variants of this second embodiment

  sation, Figures 6 and 7 are schematic views

  other alternative embodiments of the invention.

  The load support according to the invention, as shown diagrammatically in FIG. 1, comprises a cylinder body 1 in which a piston 2 slides in leaktight manner This piston therefore delimits inside the body 1 a chamber 3 of variable volume which is connected by a conduit

4 to a reservoir 5 of fluid.

  The conduit 4 is equipped with a closure member

  6 here shown in the form of a dispenser drawer 7.

  One of the ends 7 a of this drawer is subjected to the effect of a return spring 8 tending to place the movable drawer in its open position of the conduit 4 The other

  end 7 b of this drawer is housed in a pilot chamber

  stage 9 connected by a conduit 10 to the variable volume chamber

ble 3.

  In the absence of pilot pressure, the effect of

  spring 8 is predominant and the drawer opens the conduit 4.

  A restriction has been schematically shown in it on the part of the duct 4 internal to the dispenser drawer. This restriction (or calibrated section) creates a flow limitation in the duct 4 when the fluid is expelled from the chamber 3 under the effect of the load C This restriction is calculated so that, if the load is left fully applied to the piston 2, a back pressure is instantly created in the chamber 3 which is transmitted to the pilot chamber 9 and which leads to the closing of the conduit 4 So that this load C can descend with the piston 2, it should be relieved If it is for example a table top, the user slightly raises the tray so that the pressure in the chamber 3 decreases or even disappears Drawer 7 is then pushed back into its open position of conduit 4 and the fluid in chamber 3 can escape, provided

  always be relieved by the user during the

  during the descent of the piston to prevent an increase in

  the pressure in this chamber At the desired level, the use

  tor loosens the plate which stops instantaneously due to the sudden increase in pressure in the chamber 3 which causes the distributor to change state 6 It will be noted that whatever the additional load applied to the piston

2, the bedroom remains closed.

  The elevation of the platform by the user is not

  hampered since the latter's action causes the pressure to drop

  sion in the chamber 3, by creating a depression there which opens the conduit 4 through which the chamber can be supplied. The restriction 11 can constitute a brake on this elevation, a branch 4 a of the conduit 4 can be installed having a unidirectional valve 12 whose the passing direction is

tank 5 to chamber 3.

  The calibration of the spring 8 will be determined as a function of the load to be supported and the desired sensitivity of the device. If the spring 8 is strong enough, a slight relief of the load will suffice to allow a descent. Similarly, the restriction 11 will be judiciously established according to the maximum descent speed that

we will wish to obtain.

  The variant shown in Figure 2, on which we find some of the elements already described with the same references, illustrates an arrangement in which the restriction 11 is placed on the conduit 4, outside the distributor 6 with, to its terminals, the one-way valve 12 This restriction can be adjusted here so that the necessary adjustments can be made to obtain a good

operation of the device.

  The device shown in these figures does not work

  only if the fluid is a liquid We will see below a

  variant embodiment adapted to a gaseous fluid.

  A second embodiment of the invention is represented by three variants, in FIGS. 3, 4 and 5 In FIG. 3, the piston 32 is hollow and has at its end plunging into the body 1 an orifice 33 provided with a valve. 34 facing the chamber 3 of the enclosure 1 The edges of this orifice 33 form the seat of the valve 34 in its closed position The valve here consists of a

  heavy body which, in case of equal pressure between the cham-

  bre 3 and the internal volume of the piston 32 (or in the event of pressure in the chamber 3 lower than that prevailing in the piston 32) is moved away from its seat by a determined distance (for example by a rear stop 34 a which retains the valve resting on the edges of the orifice 33 inside the piston) which defines the section for passage of the fluid from the chamber 3 to the piston 32 This passage section plays

  the same role as restriction 11 of the previous realizations

  tes, that is to say create a pressure increase in the chamber 3 when the flow of fluid displaced by the depression of the piston 32 in the chamber 3 is higher than that can

  allow this calibrated section to flow freely.

  If this is the case, the valve is subjected to a pressure

  differential sion whose resultant R is opposite to the

  traction P of gravity (corrected for Archimedes' thrust if this is not negligible, in the case of liquid fluid for example) and when it overcomes it leaves the valve 34 in the direction of its seat Communication between the room 3 and the internal volume of the piston 32 is then interrupted

and the piston is immobilized.

  This condition is fulfilled under the effect of the load C If we want the piston to descend nevertheless, it

  should relieve this load until a result

  te R which becomes less than the attraction P Under these conditions

  tions, the valve 34 is open again and the fluid can flow through the orifice 33 We will be careful, for the realization of this valve, to the effects of driving valve 34 towards its seat due to the flow fluid La

  lowering the load must therefore be accompanied by an

  the user must exercise over it.

  To raise this load, simply pull it upwards. Under these conditions, the valve opens and is kept open as long as the lifting action lasts. As soon as the user releases the load, the valve closes and the

  charge stops instantly.

  The variant of FIG. 4 relates to a valve 35 constituted by an elastic blade which, in the rest position, delimits a restricted section calculated to pass upstream from the orifice 33 for the fluid flowing from the chamber 3 towards the piston 32 For this purpose, the blade can, in this position,

  rest on a stop 35 a which determines the restricted section.

  This elastic blade can therefore be pressed against the orifice 33 if the pressure which it undergoes on its face facing the chamber 3 is greater than that facing the orifice of a

  sufficient value to overcome the spring effect of this blade.

  The advantage of such a provision compared to the previous-

  You resides in the fact that the device does not have to be necessarily vertical to control the vertical movement of a load to which it would be connected by a set of deflection levers. In this FIG. 4, the channel has also been represented.

  bypass 4 a with its one-way valve 12.

  A variant of the two is shown in Figure 5

  previous embodiments in which the valve 36 is main-

  held apart from its seat by a spring 37 This valve has means for adjusting the maximum value of the distance on

  separating from its seat These are schematically represented

  ted by a rod 38 fitted with an oblong eyelet 39 at its end opposite the valve, the length of the rod being adjustable by more or less pronounced screwing of the eyelet on

the stem.

  Figures 6 and 7 illustrate two other alternative embodiments of the invention in which the reservoir 5 is incorporated in the cylinder body, In these two figures, the piston 2 therefore shares the body 1 of the cylinder in a chamber 3 and the reservoir 5 The piston 2 has a through rod so that its movement in the body 1 results in a simple transfer of volume between the chamber 3 and

  the tank 5 The device is completely sealed against

  screw from the outside filled with a fluid (liquid or gaseous) under

  pressure or not It can be delivered in the form of a cartridge

  che factory adjusted to be inserted in a base In the case of a gaseous fluid, the pressure will be high enough so that the gas has lost a large part of its elastic compression with respect to the load in order to be sufficiently

stiff on blocking.

  In Figure 6 the load C is coupled to the piston rod, the body 1 of the cylinder remaining fixed (secured by

  example of a base) In Figure 7 the load is solidai-

  re of the body 1 of the jack, the piston being fixed integral with the

  base In this case, it will be noted that it is advantageous to pre-

  see a valve 35 with a blade rather than a valve weighing 34 as in FIG. 6 The variant of FIG. 7 can also operate in any position, to lock against a

  mobile effort with a speed at least equal to that reached

  te by the load C under the effect of gravity when the channel

3 is open.

  The invention is not limited to the various valves described above, but also covers those which

  could perform the same functions.

  It will be noted, with regard to the embodiments of the invention using a liquid fluid, that the

  tank or the hollow piston will be provided with a vent allowing

  both filling, emptying their internal volume, and maintaining the atmospheric pressure of the free surface of the liquid This vent may receive a plug to prevent leaks during transport of the device, and be equipped with an automatic shutter in order to avoid a flow of

  liquid if the latter reaches its level.

  The simplest application of the invention resides in a telescopic column directly supporting the

  load, but this device can be incorporated into a mechanical

  me more complicated with systems of deflection levers which

  transmit all or part of the weight of the load to the

  port according to the invention Insofar as only a part

  ment of the weight of the load would be transmitted to the support, it would be interesting to provide means of

  grip for the user when he has to lift or lift

manage this charge.

  One of the advantages of the invention lies in the simplicity of its construction, and in the safety of its operation. In fact, no part is placed under strong unbalanced stress, unlike most of the

known actuator devices.

Claims (9)

  1 Telescopic self-locking support for   load, comprising a cylinder body (1) in which a   ton (2) is mounted with sealed sliding and defines a cham-   bre (3) of variable volume, one of the cylinder body elements   piston being integral with the load, the other being fixed, charac-   terized in that the chamber (3) is connected to a reservoir (5)   fluid through a conduit (4) fitted with an interrupter   tion (7) movable between an open position and a closed position of the duct, the open position establishing communication between the chamber (3) and the reservoir (5) through a calibrated section (11), the movable member being subjected to two opposing forces, one of return to its open position, the other of return to its closed position, the latter being generated by the pressure prevailing in the variable volume chamber (3 ), the return force at the opening being less than the return force at the closure generated by the pressure prevailing in the chamber under the effect of the total weight of the load (C) whatever   the position of the interrupting member (7).   2 Support according to claim 1 characterized in that the interrupting member is constituted by a drawer (7) distributor (6), one end (7a) is subject   to the effect of a return spring (8) in its open position   and the other end (7 b) of which is subject to the effect   of the pressure of the variable volume chamber (3).   3 Support according to claim 2 characterized in that the calibrated section (11) is provided in the drawer (7) of the distributor (6).   4 Support according to claim 2 characterized in that the calibrated section (11) is formed outside the distributor (6), on the conduit (4) connecting the chamber to the tank. Support according to claim 1 characterized in that the shutter member is a movable valve (34, 35,   36) with respect to a fixed seat and in that the section cali-   brée is formed by the fluid flow section   delimited by the seat and the valve (34, 35, 36) in the posi- tion of the latter.   6 Support according to claim 5 characterized in that the valve (34, 35, 36) is carried by the piston (32), the reservoir being constituted by an interior volume of this piston (32) which is hollow.   7 Support according to claim 6 characterized in that the restoring force (P) of the valve in its open position is generated by the attraction of gravity   on the valve (34), movable vertically relative to the pis- tone and weighty for this purpose.   8 Support according to claim 6 characterized in   what the return force of the valve in its open position   ture is generated by a spring (37) coupled between the piston (32) and the valve (36).   9 Support according to claim 6 characterized in that the valve is constituted by a flexible elastic blade (35) forming a shutter for an orifice (33) of the piston,   normally removed from this hole.   Support according to any one of the claims   tions above characterized in that the reservoir (5) is constituted by the volume of the cylinder body (1) located opposite the piston with respect to the chamber (3), the piston (2) being traversed by the conduit ( 4) of calibrated section and comprising the interrupting organ (34, 35).   11 Support according to claim 10, characterized in that the piston (2) opposite opposite the chamber (3)   and opposite the tank (5) an identical surface.