Arrangement for adjustments of pedestals designed for furniture or the like

Technical field:

The present invention relates to an arrangement for adjusting the position of objects, for example pedestals designed for furniture or the like, comprising an initial section which is supported directly or indirectly by a sub- surface, and second section which is movable relative to the first section and which supports the objects and which is movable in two opposite directions relative to the first sections between different adjustment positions, in which the two sections are capable of being locked relative to each other with respect to the said relative movement by means of a controllable locking arrange¬ ment which has an actuating device for re-setting the locking ar¬ rangement between the locking and release positions.

Background:

Gas springs are widely used for the adjustment of furniture pedestals , such as pedestals for office chairs . However these exhibit many disadvantages . Functional errors on their part can occur ex¬ tremely unexpectedly and suddenly as a result of shortcomings in the material, with the result that the pedestal collapses quite sudden¬ ly, so that bodily harm can be occasioned to the person who is occu¬ pying the furniture concerned. Furthermore oil is employed in certain designs as the damping medium, so that damage to floor and carpets occurs in the event of leakage in the structure.

The aim of the invention:

The aim of the present invention is to eliminate the problems described above and to provide a simple, reliable solution which is easy to actuate.

The solution:

The said objectives are achieved by means of an arrangement in accordance with the present invention which is characterized in that the locking arrangement comprises essentially an initial and a

second set of locking bodies and an initial and a second seating with which the first or the second set of locking bodies are designed to interact, whereby the locking bodies attempt to adopt a locking posi¬ tion by clamping between the associated seating and a clamping sur¬ face which is connected with one of the said sections, and to be re-, adjusted to the release position by the movements of at least one set of locking bodies from the appropriate seating by means of the actuating device.

Brief description of drawings:

The invention will be described in greater detail in the following by reference to some embodiments and to the appended diagrams, in which Fig. 1 illustrates a partially broken view in longitudinal section of a furniture pedestal provided with an adjustment device in accor¬ dance with the invention, in an initial embodiment in the locking po¬ sition; Fig. 2 illustrates a partially broken view of a longitudinal section through the adjustment arrangement in accordance with the invention in an initial release position so as to shorten the pedestal, and Fig. 3, in a view which corresponds to that provided in Fig. 2, illustrates the adjusting arrangement in a second release position to extend the pedestal. Fig. 4 by means of a partially broken central longitudinal section illustrates the adjustment arrangement in accor¬ dance with the invention in a second embodiment in a locking position and Fig. 5, by means of partial view, illustrates the adjustment ar¬ rangement as shown in Fig. 4 in a release position for either exten¬ ding or shortening the pedestal. By means of a partially broken cent¬ ral longitudinal section Fig. 6 illustrates the adjustment arrangements in accordance with the invention in a third embodiment in a release position for shortening the pedestal. Fig. 7 illustrates the arrange¬ ment as shown in Fig- 6 in a release position for extending the pe¬ destal.

Best mode of carrying out the invention:

Fig. 1 illustrates a furniture pedestal 1, for example, an office chair where the furniture section 2, is indicated in partially broken fashion by means of a dot- dashed line. In the case of office chairs the furniture section comprises the chair cushion with possibly a

back support, not shown, and possibly arm rests . To simplify matters the base portion of the pedestal is not illustrated but is indicated merely by broken flange sections 3. In the case of an office chair the base portion normally comprises a plurality of four or six arms directed sideways which are mounted on feet or wheels which rest on the floor. The pedestal 1 is divided into a fixed section 4 which is supported by the sub-surface, i.e. the floor, and a movable sec¬ tion 5 which supports the furniture section 2. The pedestal 1 is of the telescopic type, whereby the fixed section 4 and the movable section 5 comprise two tubular sections with the movable section ca¬ pable o displacement inside the fixed section.

In accordance with the invention the pedestal 1 has an adjust¬ ment device 6 which has an actuating device 7 and a locking device 8. The adjustment device is thus designed to facilitate adjustment of the pedestal 1 by moving the movable section 5 relative to the fixed section 4 and locking both sections relative to each other by means of the locking arrangement 8. The locking arrangement 8 has an ini¬ tial and a second set of spherical locking bodies 9, 10 which are arranged to interact each with its seating 11, 12. The two seatings 11, 12 are firmly connected with the movable section 5 and each has a tapered seating surface 13. These are located concentrically with a column 14, which is in the form of a bar, tube or the like, which extends inside the pedestal and is firmly connected with the fixed section 4. Furthermore the locking arrangement has two supporting elements 15, 16 in the form of washers made from relatively rigid material, for example metal, of which one washer 15 is fixed in the movable section 5 and has a recess for the column 14 and for the actuating device 7, whilst the second washer 16 is located in the fixed section 1, but is designed to follow the movement of the mov¬ able section and to form a bottom section of the movable section. The latter-mentioned supporting element also has a central recess for the column 14. Inside the two supporting elements 15, 16 resilient elements 17, 18 are provided in the form of two ring-shaped washers made from a resilient material such as rubber. Thus the resilient elements 17, 18 are elastically resilient and are so positioned that they attempt to hold the locking bodies 9, 10 in the locking position illustrated in Fig. 1. The locking position is obtained as a result

of jamming between the two seating surfaces 13 and a casing surface 19 of the column. The upper supporting element 15 is maintained in a suitable manner in position inside the movable section, for example by means of a press set or by means of a locking ring or the like, which is not shown, whilst the lower supporting .element 16 is kept pressed against the locking arrangement by means of a strong spiral spring 20 which attempts to lengthen the pedestal 6 by causing dis¬ placement of the movable section 5 relative to fixed section 4, which will be described in greater detail in the following.

The actuating device 7 has an actuating lever 21 with handle 22. By means of a pivot 23 the actuating lever is rotably mounted in the movable section, through the walls of which the lever extends, and by means of a further pivot 24 is connected with an actuating rod 25, the lower end of which is firmly connected with an actuating ring 26. This is concentric with respect to the column 14 and its height is such that the two sets of locking bodies 9, 10 are simul¬ taneously permitted to remain in the locking position, i.e. clamped. As a result of the positioning of the actuating rod 25 the upper sea¬ ting surface 13 is interrupted at the rear of the rod, because the locking bodies 9 cannot extend all the way round.

Furthermore the adjustment arrangements is provided with a damping element 27 in the form of an elastic ring made for example of plastic, rubber or the like which is located in the movable section 5, more particularly in a groove in the latter. The outer periphery of the damping element 27 rests against the inside of the fixed sec¬ tion 4 of the pedestal and damps the movement between the movable section 5 and the fixed section 5 as a result of displacement between these sections is tilted somewhat and as a result expands radially, particularly as regards the shortening movements, i.e. movements where the movable section 5 is moved downwards in the diagram.. This is especially valuable with chairs where a sudden lowering move¬ ment is regarded as uncomfortable and which can on occasions cause damage to the back.

The adjustment arrangement in accordance with the invention is. located in the locking position, i.e. with the movable section 5 in a selected adjustment position relative to the fixed section, i.e. with the furniture section 2 at a selected height when the actuating hand-

e 22 is not touched. When it is desired to shorten the pedestal 2, i. e. in the case of a chair to lower the chair cushion, the locking arrangement is re-set in accordance with the first embodiment to an initial release position as shown in Fig. 2. Here the actuating handle is raised performing an upward movement, in the direction shown by the arrow, whereby the actuating rod 25 is made to press the actuating ring downwards , as a result of which the second, i.e. the lower, set of locking bodies 10 is . moved downwards somewhat so that they leave their locking position clamped between the seating surface 13 and the casing wall 19 of the column 14. This is possible because of the resilience of the resilient component 18 which is thus deformed and permits this downwards movement on the part of the locking bodies 10. This hence permits the movable section 5 of the pedestal to be lowered, i. e. the pedestal is shortened and the furniture sec¬ tion 2 can be adjusted from a higher position to a lower position. As a result of this movement the clamping action between the upper set of locking bodies 9 automatically ceases due to the direction of the clamping surfaces . When the desired position has been achieved, the handle 22 is released which then automatically adopts a neutral position as a result of the return movement of the locking bodies 10 under the influence of the elasticity of the spring element 18.

Fig. 3 illustrates the position of the adjustment arrangement during adjustment from a lower position to a high position on the part of the movable section 5 and hence of the furniture section 2, which however for the sake of simplicity has been omitted from Fig. 2 and 3. During this the actuating handle 2 is moved in the direc¬ tion shown by the arrow and the actuating ring 26 is raised some¬ what and as a result lifts the first set of locking bodies 9 from their locking position to a release position, whereby the locking bodies 9 are able to perform this movement because of the resilience of the spring element 17. This hence enables the movable section 5 to move upwards , this being brought about as a result of the action of the spiral spring 20 which can expand and raise the furniture section, possibly even with a person sitting thereon. When the desired height has been adjusted, the handle 22 is released, whereupon the actuat¬ ing ring 26 reverts to its neutral position shown in Fig. 1 as a re¬ sult of the attempt of the spring element 17 to return the locking

0 P1

bodies 9 to the locking position . When this position has been adopted, both sections 4 and 5 are locked to each other.

Fig. 4 and 5 illustrate a second embodiment of the adjustment arrangement in accordance with the invention. In this example the actuating ring is subdivided, into an upper and a lower actuating ring 28, 29, the said rings being arranged to interact with each of the two sets of locking bodies 9, 10. Furthermore the actuating de¬ vice, here designated as 30, is provided with a rotating shaft 31 which is rotably mounted in a hole 32 in the movable section 9. The fixed section 4 has a vertical slot 33 in which the actuating device

30 is permitted to move with its rotating shaft 31. The rotating shaft

31 furthermore projects between the two actuating rings 28, 29 by means of a cam element 34 located on the rotating shaft 31, the cam in the position of the actuating device 30 shown in Fig. 4 having a relatively low height, in the example shown a height essentially iden¬ tical with the diameter of the rotating shaft 31, but when the rotating device 30 is rotated a little around its axis of rotation 31 with a greater dimension in height. The cam element 34 preferably has an oval shape or the like. Result is that in the position shown in Fig.

4 the actuating rings 28 are committed to be lowered in such a way that the locking bodies 9, 10 are kept in the locking position under the action of the associated elastic elements 17, 18. As a result the pedestal 1 is kept locked in a selected position against the mutual displacement movement between the two sections 4, 5. When it is desired to change the position of the pedestal, the actuating handle, here designated as 35, of the actuating device, is swivelled in any arbitrary direction so that the rotating shaft 31 is twisted in either direction, whereby the cam element 34 is made to expand upwards and thus displace the two actuating rings 28, 29, and thereby lower all the locking bodies 9, 10 against the action of the associated spring elements 17, 18. This releases the locking between the two sections 4, 5 in the pedestal so that the movable section 5 can either be raised or lowered as required. For the sake of simplicity Fig. 4 and 5 cer¬ tainly show the same height for the movable section 5, but it is ob¬ vious that adjustment and locking between the two sections of the pedestal can take place at widely differing heights, even though the height shown in Fig. 5 indicates that only lowering of the movable section 5 is possible.

Fig. 6 and 7 illustrate the adjustment device in accordance with the invention in the third embodiment with the arrangement in the release position for shortening the pedestal in Fig. 6 and in the re¬ lease position for lengthening the pedestal in Fig. 7. In this third example the spring 20 is instead located at the top of the arrange¬ ment and is clamped between a supporting washer 37 which is sup¬ ported by the column 14 and one end 38 of a group of cylinders fixed in the movable section 5 with a cylindrical casing 39. Thus the column 14 extends into this group which also encloses the adjust¬ ment arrangement 6. The actuating rod 25 also extends into the cy¬ linder group at the side of the column 14, as indicated by dashed lines . The seatings 11, 12 for the spherical locking bodies 3, 10 are formed by a sleeve-like element which is fixed in the cylindrical cas¬ ing 39. The fixed portion 4 extends outside the movable portion 5 and exhibits a play relative to the latter so that the movable section can move relative to the fixed section. The column 14 is rotably mounted by means of a bearing arrangement 40 in the foot 3 of the pedestal so as to permit a rotary movement on the part of the sup¬ ported furniture even when the adjustment arrangement is in the locked position. In this embodiment the damping element 27 is de¬ signed in a manner different from that in the above-mentioned examp¬ le. Here the damping element is gripped at the bottom in the cylind¬ rical casing 39 of the cylinder group and at the top obtain support against the metal washer 16, but in the downward direction it is free to deform to a certain extent. The damping element 27 is made from an elastic material, for example, plastic, rubber or the like and has a central punched hole 41 the diameter of which is originally selected to be considerably less than the diameter of the column 14, for ex¬ ample several, millimeters in relation to the diameter of the column which is of the order of 10 mm. As a result of punching the hole 41 exhibits a degree of taper with a diameter which increases upwards, which in conjunction with the freedom of movement of the damping element downwards gives a high degree of damping of the relative displacement movement of the two sections 4, 5 during the raising of the pedestal, i.e. during the lowering of the movable section 5. Here the hole 41 tries to reduce its diameter, whilst in the opposite direction, i.e. raising of the pedestal, the hole attempts to increase

its diameter. Thus in Fig. 6 the movable section 5 is lowered by depressing the actuating lever 21 in the actuating device 7. In this example the actuating lever 21 is namely rotably mounted in a pivot pin 42 located near the wall of the movable section 5, so that the actuating rod 25 is pressed downwards which results in the locking bodies 10 being pressed downwards and released from their seating 12, so that the pedestal can be lowered. As a result of friction against the column 14 the damping element 17 attempts to press against the supporting washer 16 and thereby increase its friction against the column and to brake the relative movement downwards on the part of the movable section without however hindering this, which results in an extremely smooth movement.

As indicated in Fig. 7, the actuating lever 21 is raised when the movable section 5 is to be raised, during which the locking bo¬ dies 9 are lifted at t±ie top from their seatings 11 and the clamped state is released. Due to the friction of the damping element 27 against the column 14 the damping element, as shown in the diagram, is deformed in such a way that it attempts to increase its diameter in the hole 41, which results in reduced friction against the column and a damping which is reduced in comparison with the lowering movement is obtained. The need for damping is for natural reasons not so great during a lifting movement, because the lifting movement takes place against the effect of a load, e.g. a person sitting on a chair. During the lowering movement however with a person sitting on a chair a higher degree of damping is required to avoid damage which could be occasioned by excessively violent locking.

The invention is not restricted to the embodiments described above and illustrated on the drawings, but can be varied in several ways within the framework of the following claims . For example the locking bodies can, be cylindrical or tapered bodies instead of sphe¬ rical. Here the column 41 can have plane surfaces and have for ex¬ ample rectangular, square or triangular cross sectional shape. The number of locking bodies 9, 10 can vary from extending in ring fashion around the column 14 to one upper and one lower locking body. The actuating device can be designed in a number of different ways. For example it is feasible that the handle be replaced by a wheel in the second embodiment. The mechanism for displacing the

actuating ring or actuating rings can similarly be designed in many different ways . The resilient elements 17, 18 can be replaced by spring washers or other spring elements . It is furthermore feasible that the two seatings face outwards towards the inner walls of the fixed section 4 and that locking is brought about against this wall instead of against the column 14 which can then be omitted. It is also possible for the arrangement to be designed for purposes other than adjustable furniture. For example the displacement movement can be directed horizontally or sloping so as to adjust special objects such as working furniture or the like.