HK1069298B - Chair - Google Patents

Description

Chair (Ref. TM. chair)

Technical Field

The invention relates to a chair, in particular to an office chair, which comprises a base; a seat support supported by a chair support column, the seat support including a forward seat support member and a rearward seat support member pivotally connected to the forward seat support member by a substantially horizontal pivot axis; a seat supported on the seat support member; a backrest secured to the rear seat support member; an adjustable length energy storage device for adjustment of the backrest and the seat relative to each other, a first end of the energy storage device being pivotally mounted on the front seat support member by an abutment, a second end of the energy storage device being pivotally supported on the rear seat support member at a distance from the pivot axis; an adjusting member rotatable about an adjusting member rotation axis for varying the distance; and a turning handle for operating the adjusting member, the turning handle being connected to the adjusting member and rotatable about a turning handle rotation axis.

Background

A chair of this type is known from DE4324545a 1. This known design is a so-called synchro-mechanism, in which the backrest and the seat are pivoted synchronously in a certain given relationship. An energy storage device in the form of a helical compression spring is provided between the front and rear seat members for generating a force acting between the front and rear seat support members urging the backrest into its forward limit position and the rear of the seat into its upper position. In addition, a so-called rocker mechanism allows the user to move his back by counteracting the restoring force of the energy storage device. The return force of the energy storage device can be adjusted by changing the distance of the energy storage device from the pivot axis from below the front seat frame member with an adjustment screw. In order to change the restoring force, the user of the chair must stand up and manipulate the swing handle.

Disclosure of Invention

It is an object of the invention to improve a chair of this type such that an adjustment of the restoring force of the energy storage device can be easily achieved.

According to the invention, this object is achieved by the following features: the turning handle is connected to the adjusting piece by a coupling piece for converting the manipulated rotary motion into an adjusting motion; the adjustment member axis of rotation is non-collinear with the rotational handle axis of rotation.

The gist of the invention is to provide a coupling between the adjustment member and the twist handle that allows a torque to be transmitted from the twist handle to the adjustment member without the axis of rotation of the adjustment member and the axis of rotation of the twist handle being collinear. This provides a greater degree of freedom in the design of the twist grip, enabling the user to manipulate it more freely, especially when the user is seated. The coupling member is designed to be able to structurally complete the adjustment system of the existing chair structure in a simple manner.

A coupling comprising a steering gear, in particular a spur gear bevel gear pair, also allows a safe transmission of high transmission forces.

According to one embodiment of the coupling, a bevel gear of the bevel gear pair has an internal thread which meshes with the other coupling part of the coupling, in particular with its complementary external gear of the adjusting part, practically without deformation, using the mechanical parts of the known chair construction.

A coupling having a flexible shaft, in particular a spring shaft, has a particularly simple construction.

A turning handle extending laterally beyond the seat support member can be easily manipulated even when the user is seated.

An adjusting element in the form of an adjusting screw is not structurally complicated.

Drawings

The details of the invention will become apparent in the following description of exemplary embodiments thereof, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of the entire chair;

figure 2 is a partially cut-away top view of the seat support of the chair according to figure 1;

FIG. 3 is a fragmentary top plan view, not in section, of a seat support like that of FIG. 2;

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 2;

FIG. 5 is a sectional view along the line V-V of FIG. 2, in comparison with FIG. 4, with the adjustment screw in a further screwed-out position;

FIG. 6 is a top view of the seat support similar to FIG. 3 showing another portion of the seat support;

FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 6;

FIG. 8 is a cross-sectional view similar to FIG. 7, showing another position of the two chair seat support members relative to each other;

FIG. 9 is a top view similar to FIG. 2 of an alternative chair seat support;

FIG. 10 is a cross-sectional view taken along line X-X of FIG. 9; and

fig. 11 is a sectional view taken along line XI-XI of fig. 10.

Detailed Description

Fig. 1 shows an office chair with a chair frame 1. The chair frame 1 comprises a base 2 supported on the floor by castors 3. A height-adjustable chair support 4 is mounted on the base 2; a seat support 5 is fixed to the upper end of the post 4. The seat support 5 is of two-piece design (consisting of two parts); it comprises a front seat support member 6 mounted on the chair strut 4 and a rear seat support member 7 hinged to the front seat support member 6 by a hinge 8 above the chair strut 4. A support tube 9, which is parallel to the pivot axis 8, is fixed in the front region of the front seat support part 6. A seat 10 is supported on the support tube 9 shortly behind its front edge 11. The support tube 9 constitutes a front bearing portion for the seat 10. The seat 10 is supported via its rear region on a bearing shaft 12 which is embedded in the rear seat support part 7. The support shaft 12 is a rear support portion for the seat 10. A seat inclination adjusting means 13 is provided on the rear seat support member 7.

A back support 14, to which a back 15 is mounted, protrudes upwardly from the rear seat support member 7 integrally formed therewith. A backrest height adjustment device 16 is provided for adjusting the height of the backrest 15 relative to the seat 10.

The described design of the seat support 5, including the arrangement of the seat 10 and the backrest 15, constitutes a so-called synchronizing mechanism. In order to vary the force that the user must overcome during adjustment or shaking, a force varying device is provided, which is generally indicated at 17 and will be described in detail below. An adjusting nut 18 projecting downward from the front seat frame member 6 is part of the force varying device 17; fig. 1 shows a freely rotatable cap 19 of the adjusting nut 18.

A handrail 20 is provided on the outboard end of the support pipe 9 near the front edge 11 of the seat 10. Only one armrest 20 is visible in the side view of fig. 1.

In order to adjust the height of the seat support 5 and of the seat 10 and backrest 15, the chair support 4 comprises a known length-adjustable gas/pneumatic spring 21, which is visible in the top view of fig. 3. The gas spring 21 is clamped in a conical clamping device 22 of the front seat support part 6. A valve control pin 23 protrudes upward from the gas spring 21; when the valve control pin is pushed into the gas spring 21, a valve located there will be opened, thereby adjusting the length of the gas spring 21. A gas spring of this type is shown and described, for example, in DE1812282C2 (corresponding to us patent 3656593). For actuating the valve control pin 23, a two-armed valve control lever 24, as described for example in DE4324545a1, is provided which is pivotally mounted on the pivot shaft 8. The first lever arm 25 of the valve control lever 24 rests on the valve control pin 23, while the second lever arm 26 can be actuated by a lever mechanism known from DE4324545a 1.

Any pivoting of the rear seat support member 7 relative to the front seat support member 6 is resisted by an energy storage device 27, which in the exemplary embodiment shown is a pre-loaded helical compression spring 28. The spring 28 is supported on the front seat support member 6 in the region adjacent the front edge 11 of the seat 10 by a pivotal abutment 29, which is visible in particular in fig. 2 and 5. To this end, the energy storage device 27 comprises a guide rod 30 which passes through the helical compression spring 28. At the other end, the helical compression spring 28 is supported on a guide block 31 of the force-varying device 17. The guide block 31 rests on a sliding surface 32 formed on a first lever arm 33 of the rear seat support part 7. The lever arm 33 is integral with the rear seat support member 7 and extends substantially downwardly from the pivot 8. From this point of view, the rear seat support member 7 has a toggle-like lever geometry. The slider 31 is movable on the guide rod 30 along the helical compression spring 28. The force-varying device 17 acts on an adjusting part 34 of the guide rod 30 opposite the abutment 29. The connecting portion 35 of the guide rod 30 abutting the adjusting portion 34 passes through the first lever arm 33 of the rear seat bracket part 7. The connecting portion 35 is bent into an elbow shape in a direction toward the rear seat frame member 7 opposite to the portion of the guide rod 30 passing through the helical compression spring 28. The adjustment portion 34 of the guide bar 30 is thus bent towards the rear seat support part 7 and arranged in the vicinity of the seat support 5.

An adjusting screw 36 is part of the force variation device 17; which is pivotally hinged to the adjustment portion 34 of the guide bar 30 by a hinge with a pivot 37.

The distance between the pivot axis 8 of the seat support members 6, 7 and the central axis of the helical compression spring 28 is indicated by a in fig. 5.

The adjustment screw 36 engages with an adjustment nut 18 embedded in a bottom wall 38 of the front seat support member 6, which is rotatable but not movable in the direction of the adjustment screw 36. At the end opposite the cap 19, the adjusting nut 18 is provided with a straight conical portion 39. A likewise straight-toothed conical portion 40 of one end 41 of the twist grip 42 meshes with the toothing of the straight-toothed conical portion 39, the two conical portions 39, 40 forming a straight-toothed bevel gear pair. The axis of rotation 43 of the adjustment screw 36 is not collinear with, but intersects, and is at right angles to, the axis of rotation 44 of the turning handle 42. The end 41 is mounted for rotation in a side wall 45 of the front seat frame member 6 but is not axially movable along the axis of rotation 44 of the twist grip 42.

The free end of the twist handle 42 is an oval handle 46 with a recessed gripping formation 47. The handle 46 has a central bore 48 at the free end of the handle 46 closed by a cap 49 disposed over the free end. A connecting bolt 50 is inserted into the bore to secure the handle 46 to the end 41 of the swing handle 42.

When the turning handle 42 is rotated, this rotation is converted by the mutually engaging conical portions 39, 40 into an axial adjustment movement of the adjustment screw 36 along the axis of rotation 43. The conical portions 39, 40 thus form a coupling by means of which the turning handle 42 is connected as an adjusting member to the adjusting screw 36. When the turning handle 42 is rotated, the guide bar 30 is pivoted about the hinge of the abutment 29 by means of a hinge having a pivot 37. As a result, the guide piece 31 moves on the sliding surface 32 of the first lever arm 33, which changes the distance a of the axis of the energy storage device 27 from the pivot 8. Since the sliding surface 32 is located at least approximately on a circular arc whose center is located above the hinge axis of the contact part 29, the distance b between the pivot axis of the contact part 29 and the intersection of the axis of the energy storage device 27 and the sliding surface 32 changes only slightly when the swing handle 42 is rotated. Thus, these adjustments do not actually change the preload of the helical compression spring 28. As mentioned above, slightly offsetting the (centre of the) sliding surface 32 with respect to the centre of the hinge formed by the abutment 29 helps to achieve: a tension force transmitted by the helical compression spring 28 always acts on the adjusting screw 36. The adjusting screw 36 is therefore always guided in the adjusting nut 18 with certainty, so that the flanks of the thread of the adjusting screw 36, which is located at the top in fig. 5, bear against corresponding flanks of the internal thread of the adjusting nut 18.

The force of the helical compression spring 28 acting on the first lever arm 33 of the rear seat support member 7 is unchanged; it is only the effective lever arm, i.e. the helical compression spring 28, that acts on the rear seat support member 7 and thus on the seat 10 and backrest 15 that varies with the distance a between the axis of the energy storage device 27 and the pivot 8. The smaller the distance a, the smaller the torque and vice versa. The adjustment force applied to the swing handle 42 can be kept constant throughout the adjustment stroke of the guide shoe 31, and the frictional force between the guide shoe 31 and the sliding surface 32 and the operating force of the mechanical coupling between the guide bar 30 and the swing handle 42 are virtually unchanged.

In order to disable the co-pivoting ability of the seat 10 and the backrest 15 in the synchronizing mechanism against the force of the helical compression spring 28, an interlocking mechanism 50 is provided, as shown in fig. 6 to 8. The interlocking mechanism 50 includes a locking lever 51 pivotally hinged to the front seat support member 6 about a hinge having a pivot 52. The pivot 52 is substantially coincident with/collinear with the pivot of the abutment 29. The free end of the locking lever 51 at a distance from the pivot 52 is provided with a horizontal pin 53 fixed to the locking lever 51, which passes through the locking lever 51 and horizontally protrudes from both sides thereof.

The counterpart 54 cooperating with the lock lever 51 is part of the interlocking mechanism 50. The counter body 54 is pivotally hinged to the front seat support member 6 about a hinge with a pivot 55. The pivots 52, 55 are spaced apart and parallel. The counter body 54 comprises two parallel and perpendicular plates 56 spaced apart at a distance and perpendicular to the pivot 55. They have a substantially approximately triangular shape and lie approximately on a circular arc on the side opposite the pivot 55 and operate as a circumferential locking portion 57; the pivot 55 is located at the center of the arc segment.

The circumferential locking portion 57 of the plate 56 is provided with four substantially semicircular locking receivers 58, two of which are arranged in pairs for each plate 56. The locking receivers 58 are complementary in width to the pins 53 of the lock lever 51 and are dimensioned such that the pins 53 can engage a pair of locking receivers 58 substantially without play to engage one of the two free ends of the pins 53 with a corresponding one of the two locking receivers 58 of the pair of locking receivers 58.

A link 60 is hinged to the counter body 54 as a link by a hinge having a pivot 59. The pivots 55 and 59 are spaced apart and parallel. The link 60 is hinged to the first short lever arm 33 of the rear seat support member 7 by means of a further hinge having a pivot 61. Pivot 61 is parallel to and spaced from pivots 8 and 59.

The locking lever 51 can be actuated by an actuating handle 63 projecting transversely from the support tube 9, as shown in fig. 1, by means of a coupling bolt 62 which is fastened by a bearing to the front seat support part 6.

Fig. 7 shows the interlock 50 in a position in which the pin 53 is positioned at the leftmost lock receiver 58 in the side views of fig. 7 and 8. In this position, the rear seat support member 7 and the back support 14 are in the most upright position (uppermost position).

Fig. 8 shows the interlock 50 in a position in which the pin 53 is positioned at the rightmost locking receptacle 58 in the side views of fig. 7 and 8. In this position, the rear seat support part 7 and the backrest support 14 are tilted to the greatest extent backwards and into a lying position.

As the distance between the pivot shafts 8 and 61 exceeds the distance between the pivot shafts 55 and 59, the pivoting of the rear seat support member 7 about the pivot shaft 8 causes the corresponding body 54 to pivot further about the pivot shaft 55 corresponding to the distance ratio. Thus, the link 60 operates as a mechanical transmission transmitting the pivoting of the counterpart 54 in association with the pivoting of the rear seat bracket member 7.

The interlocking mechanism 50 is normally not active in order to enable a synchronous movement of the seat support parts 6, 7 relative to each other. When the user stops the synchronizing mechanism, i.e. when he wants to interlock the seat support parts 6, 7, he will first move the rear seat support part 7 to a desired position relative to the front seat support part 6 by a corresponding pressure acting on the backrest 15 and thus on the rear seat support part 7 via the backrest support 14. Thereafter, the user actuates the operating handle 63 to move the pin 53 in a direction toward the circumferential locking portion 57. The pins 53 then either immediately engage with their adjacent locking receivers 58 or the user continues to fine-tune the position of the seat support members 6, 7 relative to each other by corresponding pressure on the backrest 15 until the pins 53 engage with the corresponding pair of locking receivers 58. After completion, the synchronization mechanism is interlocked in the desired position of the seat support parts 6, 7 relative to each other. By means of its gearing, the connecting rod 60 is able to ensure precisely graduated discrete positions of the seat support parts 6, 7 relative to one another, although the distance of the locking receivers 58 from one another in the circumferential direction of the circumferential locking portion 57 is not too small.

Fig. 5 to 8 and fig. 10 and 11 show details of the seat inclination adjusting means 13. For seat tilt adjustment, the height of the support shaft 12 on which the rear part of the seat is supported can be varied. For this purpose, the bearing shaft 12 is supported by a first lever arm 70 of a tilt adjustment lever 71 which is pivotable about a pivot axis 72 parallel to the pivot axis 8. A tilt adjustment screw 75 is hinged to the second lever arm 73 by means of a hinge having a pivot 74 also parallel to the pivot axis 8. The tilt adjustment screw 75 is mounted to be axially movable but not rotatable. The tilt adjustment screw engages a tilt adjustment nut rotatably but non-movably embedded in the bottom wall 77 of the rear seat frame member 7 in the direction of the tilt screw 75. At the end opposite the pivot 74, the tilt adjustment nut 76 has a straight conical section 78, the toothing of which meshes with a likewise straight conical section 79 of the end 80 of a tilt twist handle 81. The two conical portions 78, 79 form a spur bevel gear pair. The axis of rotation 82 of the adjustment screw 75 is not collinear with the axis of rotation 83 of the tilt turn handle 81, but intersects and is at a right angle. The rotation axes 44 and 83 of the turning handles 42 and 81 are parallel; the handles 42 and 81 project on the same side of the seat support 5. The end 80 is mounted in a side wall 84 of a housing 85 for rotation but is prevented from rotational axial movement along the rotational axis 83 of the tilt turn handle 81; the housing 85 is fixed to the rear seat support member 7.

The free end of the turning handle 81 is also an oval handle 46, as is the turning handle 42, and reference is therefore made in this connection to the description of the turning handle 42.

Any rotation of the tilt turn handle 81 is translated by the interengaging tapered portions 78, 79 into an axial adjustment movement of the adjustment screw 75 along the axis of rotation 82. Thus, the tapered portions 78, 79 constitute a coupling member by which the tilt knob 81 is connected as an adjusting member to the adjusting screw 75. When the tilt turning handle 81 is rotated, the tilt adjusting lever 71 is pivoted about the pivot shaft 72 by a hinge having the pivot shaft 74. Thereby adjusting the height of the supporting shaft 12 above the ground and thus the inclination of the seat 10. The higher the bearing shaft 12 is set, the more the seat 10 is inclined downwards in the direction towards its front edge 11.

In another embodiment (not shown), the mechanical coupling of the rotational movement of the turning handle 42 about the rotational axis 44 to the rotational movement of the adjustment screw 36 about the rotational axis 43 is realized by a flexible shaft, in particular a spring shaft, instead of a bevel gear pair. Flexible force transmission shafts of this type are well known. Such a flexible shaft also serves to achieve a mechanical coupling of the rotational movement of the tilting swivel handle 81 about the rotational axis 83 with the rotational movement of the adjustment screw 75 about the rotational axis 82.

Claims (7)

1. A chair, comprising:

-a base (2);

-a seat support (5) supported by a chair column (4), the seat support (5) comprising a front seat support member (6) and a rear seat support member (7) pivotally connected to the front seat support member (6) by a substantially horizontal pivot axis (8);

-a seat (10) supported on the seat support member (6, 7);

-a backrest (15) fixed to the rear seat support part (7);

-an adjustable length energy storage device (27) for adjustment of the backrest (15) and seat (10) relative to each other, a first end of the energy storage device (27) being pivotally mounted on the front seat support part (6) by means of an abutment (29), a second end of the energy storage device (27) being pivotally supported with its support axis at a distance (a) from the pivot axis (8) on the rear seat support part (7);

-an adjustment member (36) rotatable about an adjustment member rotation axis (43) for varying the distance (a);

-a turning handle (42) for operating the adjusting member (36), the turning handle (42) being connected to the adjusting member (36) and rotatable about a turning handle rotation axis (44);

-wherein the turning handle (42) is connected to the adjusting member (36) by a coupling member (39, 40, 18; 39, 40, 64) for converting the rotational movement of the operation into an adjusting movement;

-the adjustment member axis of rotation (43) is not collinear with the turning handle axis of rotation (44);

-the energy storage device (27) is supported at a second end on a guide shoe (31), the guide shoe (31) resting on a sliding surface (32) formed on a lever arm (33) of the rear seat support part (7), the sliding surface (32) being located at least approximately on a circular arc whose center is located above the hinge axis of the abutment (29).

2. A chair in accordance with claim 1, characterized in that the coupling (39, 40, 18; 39, 40) comprises a steering gear (39, 40).

3. A chair according to claim 2, characterised in that the steering gear (39, 40) is a bevel gear pair.

4. A chair according to claim 3, characterized in that a bevel gear (39) of the bevel gear pair (39, 40) has an internal thread which meshes with a complementary external gear of the other coupling part of the coupling member (39, 40, 18; 39, 40).

5. A chair according to claim 1, wherein the coupling is a flexible shaft.

6. A chair in accordance with claim 1, characterized in that the turning handle (42) protrudes laterally from the seat support part (6, 7).

7. A chair according to claim 1, wherein the adjustment member (36) is an adjustment screw.