MXPA96004066A - Trab chair - Google Patents

Abstract

The present invention relates to a chair comprising: a seat assembly including a molded support element, the support element having a generally planar part arranged centrally, a control holder secured to the flat part of the support element, a transverse recess formed in the flat part on the control bra, a cross brace disposed in the recess and connected to the control bra with the ends extending out of the control bra, and a pair of arm support assemblies, each connected to one end of the transverse clamp

Description

WORK CHAIR BACKGROUND OF THE INVENTION l. Field of the Invention The present invention relates, generally, to work chairs, of the type used in office environments, for example, and, more specifically, it refers to a novel construction of a work chair, which is highly functional and it is easily manufactured and assembled. 2. Description of the Prior Art Numerous constructions of work chairs are known, of the type used in office environments, for example. A typical work chair has a cushioned seat and a relatively low backrest. The chair is usually supported on a base, which has a plurality of casters to allow this chair to move easily in the work space. The chair may or may not have arms and other features, such as an adjustable seat and backrest height. In general, known work chairs are relatively inexpensive and lightweight construction. The chair seat of the prior art, now under consideration, is traditionally a set of an upholstered foam cushion, secured to a wooden or injection molded plastic frame. The frame is screwed to a control bra, secured to a base of the chair. If the chair has the feature of adjustable seat height, an operating lever traditionally extends out of the control bracket, to the surface mounted on the seat frame. In addition, if the chair has arms, these arms are typically supported by the surface of the frame elements, mounted to the seat frame. If the chair has a height adjustable backrest, the mechanical adjustment mechanism is often exposed, depreciating the appearance of the chair. The use of a wooden or injection-molded seat frame, with levers and the surface of the arm frames mounted on it, can create a chair construction that has an undesirable appearance, because several mechanical parts are exposed . Therefore, it is convenient to provide a work chair that has the characteristic of adjustable seat height, where an operating lever is hidden. It is also convenient to provide a work chair that has arm supports, which are secured to the seat frame firmly, but essentially in a hidden manner. Even more, it is convenient to provide a work chair that has a mechanism for adjusting the height of the backrest, which is reliable in its use and also aesthetically pleasing in its appearance. Likewise, it is convenient to supply a work chair that is economical to manufacture and that can be transported in the unassembled condition, due to the ease of assembly at its destination. BRIEF DESCRIPTION OF THE INVENTION The present invention overcomes the disadvantages of the prior art, by the provision of a chair having a seat assembly which includes a seat support member, blow molded. This support element has a flat portion for attachment to a control bra. A transverse recess is formed in the flat portion, below the control holder, which receives a transverse clamp. A pair of arm support frames is secured to the ends of the transverse clamp and to the control bracket by screws. Therefore, the arms are easily assembled to the chair and the transverse clamp is substantially hidden from view. In another aspect of the invention, a pedestal is secured to the control holder and contains a gas cylinder for raising and lowering the seat assembly. Another recess, formed in the seat support element, receives an operating lever, for actuating the gas cylinder. The operating lever is substantially flush with the surface of the support element and, thus, hidden from view. In still another aspect of the invention, the chair is provided with a seat back adjustment mechanism, to adjust the outward position of the backrest relative to the seat. This adjustment mechanism comprises a pair of parallel spaced tubular elements connected to the seat backrest and received telescopically by the control brace. A bolt, which extends through the control bra, cooperates with a clamping bar, to fix the tubular elements to the control bra. Yet another aspect of the invention relates to an adjustable height seat backrest, wherein a blow-molded seat support member is provided with wedge-shaped channels to receive a pair of tubular elements of a supporting frame backup. The tubular elements can be adjusted to a variety of positions within the channels and are held there by a single bolt. BRIEF DESCRIPTION OF THE DRAWINGS The above characteristics and other novel features of the invention will be better understood from the reading of the following detailed description, taken in conjunction with the accompanying drawings, in which: Figure 1 is a perspective side view of a work squeak constructed in accordance with the present invention; Figure 2 is a perspective view, with separate parts, of the work chair, showing the construction of the bottom side of the seat; Figure 3 is a perspective view, with separate parts, of the back part of the seat back; Figure 4 is a perspective view of the rear part of the seat back, in the assembled condition; Figure 5 is a partial cross-sectional view, taken substantially along line 5-5 of Figure 4; Figure 6 is a bottom plan view of the chair; Figure 7 is a partial cross-sectional view, taken substantially along line 7-7 of Figure 6; Figure 8 is a partial cross-sectional view, taken substantially along line 8-8 of Figure 6; and Figure 9 is a partial cross-sectional view, taken substantially along line 9-9 of Figure 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and initially to Figure 1, a work chair, constructed in accordance with the invention, is generally designated by the reference numeral 10 and includes a seat assembly 12 and a backup set 14. In the illustrated embodiment, the seat assembly 12 and the backup assembly 14 include cushions, 16 and 18 respectively, covered by a suitable fabric. The cushions 20 of the arms are supported by tubular frames 22. A seat support member 24, which will be described later in detail, is supported on a pedestal 26, which, in turn, is connected to a base 28. This base 28 comprises a plurality of legs 30, each equipped with a suitable wheel 32, to facilitate movement of the chair around the work space. Figure 2 shows the bottom side of the chair 10, in a perspective view with separate pieces. As seen there, the seat support member 24 of the seat assembly 12 is molded from a suitable plastic and is formed with a central portion 34, generally flat, to which the control holder 36 is screwed. This control holder 36 extends through a transverse recess 38 in the support element 24. This recess 38 receives a transverse clamp 40 to which the arm frames 22 are connected by the bolts 42. Another recess 44 is formed in the support member 24, which goes from the center of the flat portion 34 to an edge of the support element 24. The recess receives an operating lever 46, paraffins which will be described later. The seat back assembly 14 is supported on the seat assembly 12 by a frame 46. A cover 50 is provided for the back surface of the backrest assembly 14. Turning now to Figures 3, 4 and 5, the seat back assembly 14 can be seen to have an adjustable height feature, provided, in part, by the support frame 48, which includes two spaced tubular elements, parallel, 52. These tubular elements 52 are bent through approximately ninety degrees and connected on the first legs by a plate 54 and on the opposite leg by a transverse bar 56. The backup assembly 14, according to the invention, includes a backrest support element 60, blow molded of a suitable plastic and formed with a pair of channels 62, which run vertically from the lower edge of the support element 60. The channels 62 are spaced in such a manner as to receive slidably the tubular elements 52 of the frame 58. As best seen in Figure 5, the channels have side walls 64 in the shape of a wedge. A bolt 66 terminated by a button 68 extends through the plate 54 and is threadedly received by a suitable holder 70, molded into the backrest support member 60. A vertical slit 72 is provided in the plate 54, so that the backrest assembly has a limited vertical movement relative to the support frame 48. When the bolt 66 is screwed into the fastener 70, the internal cylindrical portion 68 of the button 68d is carried against plate 54, by forcing the tubular elements 52 in a wedge coupling with the side walls 64 of the channels 62, thereby locking the backrest support element 60 to the frame 48 in a desired vertical position. The cover plate 50, which may be made of metal * or of molded plastic construction, extends through the back of the backrest support element 60. This cover 50 is held in place in the upper part by a tongue 74 and the groove 76 formed in the support element 60 and in the bottom by a collar 78, formed integral with the cover 50 and received within an annular recess, formed on the button 68. Suitable S-clips 77 may be used to retain the tab within the slit 76 (see Figure 2). The tubular elements 52 of the frame 48 exit from below the cover 50 through the slits 80, provided in the lower bottom edge of the cover 50. Thus, the cover 50 covers the entire backrest of the support element 60, completely concealing the height adjustment mechanism. As best seen in Figure 3, the upper legs of the tubular elements 52 of the frame 48 are received within the openings 81 of the support member 60 and are placed there, to give added support to the backrest assembly 14 by the frame 48. Turning now to Figures 6, 7 and 8, the details of the seat support member 24 can be seen in an amplified illustration. The control bra 35 has a generally C-shaped cross section, with a pair of opposite flanges 82, extending outward, to mount the bra 36 to the flat portion 34 of the support member 24 by suitable fasteners, such as fastening nuts 83. The arm frames 22 comprise a pair of tubes 84 joined at their lower ends by the bands 86. The bolts 42 fasten the bands 86 to the support member 24 through the threaded holes in the transverse clamp 40, which it is placed in the recess 38, under the control bra 36 and below the bands 86. For the added strength, the spacing of the holes in the transverse clamp 40 is such that the ends of the arm tubes 84 and associated bands 86 are tightly butted against the respective sides of the control bra 36. According to the invention, the seat backrest 14 of the chair 10 has a back-restoring feature h outside, which allows this backrest 14 to be adjusted horizontally with respect to the seat 12. With particular reference to Figures 7 and 8, this feature is achieved by the telescopic relationship of the back support frame 48, within the control bra 36. The spacing of the tubular elements 52 of the back support frame 48 is such that the elements 52 slide in close proximity to the side walls of the control bra 36. Once the desired position of the backrest is selected towards outside, a clamping bar 90 having ramp surfaces 92 (Figure 7), is brought tightly against the tubular elements 52 by a bolt 94, connected to a button 96, which extends through an opening in the control holder 36. The clamping bar 90 thus pushes the tubular elements 52 in engagement with the inner walls of the control holder 36 and holds the elements 52 there securely. In order to inhibit the accidental removal of the frame 48 from the seat assembly 12, the tubular elements 52 extend forwardly of the gas cylinder 100 and are joined there by the transverse bar 56. In this manner, the cross bar 56 acts as a stop against the cylinder 100 to prevent complete removal of the frame 48 from the control bra 36. In order to provide an increased support for the seat assembly 12, the control bra 36 is provided at its front end with a tube transverse 101 V-shaped, connected there, for example, by welding. The cross tube 101 fits snugly within the recess 102, of type V, formed in the support element 24 (Figure 2). The chair 10 of the preferred embodiment also has an adjustable seat height feature, as best shown in Figure 9. Arranged within the recess 44 of the seat support member 24, is the operation lever 46. A flange 103, formed on the element 24, acts as a fulcrum for the pivoting movement of the lever 46, this flange 103 cooperates with an opening 104 in the lever 46. One of the bolts holding the control bra 36 to the support member 24, cooperates with the rim 103 to trap the lever 46 in its position within the recess 44. This lever 46 extends from the center of the control holder 36 to an edge of the seat 12 and thus installed, the proximal end 106 of the lever 46 acts as a button 108 on the upper part of the gas cylinder 100. A resilient foam element 110 can be used to orient the lever 46 to a non-operative position. The gas cylinder 100, which is of a well-known conventional design, provides for the rise and fall of the seat assembly 12 on the pedestal 26, when the lever 46 is actuated. The user of the chair can operate the lever 46 by reaching it under the seat and manipulating the distal end 112 of the lever against the force of the foam element 110. The use of a foam element 110 also reduces the rattle of the operating lever 46. It can now be appreciated that the chair 10 of the present invention supplies a highly functional and easily manufactured structure. Also, due to the hidden nature of the lever 46 for adjusting the height of the seat and the mechanism for adjusting the height of the backrest, the chair has a simple, aesthetically pleasing overall appearance. This chair 10 is also easy to assemble and, therefore, can be easily transported in the unassembled condition to further facilitate transportation. While the present invention has been described in relation to its preferred embodiment, those skilled in the art will understand that many changes and modifications can be made without departing from the true spirit and scope of the invention. Accordingly, it is intended that the appended claims cover all such changes and modifications that are within the true spirit and scope of this invention.

Claims (22)

1. CLAIMS 1. A chair, which comprises: a seat assembly, including a molded support element, this support element has a portion, generally flat, arranged centrally; a control holder, secured to the flat portion of the support element; a transverse recess, formed in the flat portion, under the control holder; a transverse clamp, disposed within the recess, with ends extending outwardly from the control holder; and a pair of arm support assemblies, each connected to one end of the transverse clamp. The chair according to claim 1, wherein the control holder has a generally C-shaped cross-sectional configuration, with rims extending outwardly. The chair according to claim 2, in which the flanges of the control bra are secured to the flat portion of the support element, which extends the recess formed therein. The chair according to claim 2, wherein each arm support assembly is screwed through a flange of the control holder and at one end of the transverse clamp. 5. The chair according to claim 2, wherein the backrest support assembly can be inserted between the control holder and the support element. The chair according to claim 5, wherein the back support assembly includes a pair of spaced, parallel tubular elements, and the tubular elements can be inserted between the control stand and the support element. The chair, according to claim 6, including a holding bar, for clamping the tubular elements to the control holder. The chair, according to claim 7, in which the tubular elements are nested within the control holder and are configured to be secured to this control holder in a plurality of positions, relative to the support element. 9. A chair, which comprises: a seat assembly, including a molded support element, having a generally planar portion, centrally disposed; a control holder, secured to the flat portion of the support element; a pedestal, secured to the control bra, this pedestal has elements to raise and lower the seat assembly; a recess in the support element, which carries the control holder to an edge of the support element; and an operating lever, mounted for pivoting movement within the recess and configured to actuate the elements to raise and lower the seat assembly. 10. A molded support frame, for the lower side of a chair seat, this frame comprises: a portion, generally flat, disposed centrally of the frame, for the union of its control support; a transverse recess, in the generally planar portion, for receiving a transverse clamp with this clamp placed between the support frame and the control bra, the transverse bracket is dimensioned and configured for joining a pair of arm frames. A molded support frame according to claim 10, further comprising: a second recess, extending away from the location of the center of the control support and configured to receive an operating lever, to operate the mechanism of seat height adjustment. 12. An adjustment mechanism, for adjusting the outward position of a backrest of a chair, relative to the seat thereof, this mechanism comprises: a bra, secured to the bottom side of the seat, this bra has a central portion generally in C shape, in cross section; a pair of parallel, spaced tubular elements for supporting the backrest of the seat on this seat, the tubular elements can be received telescopically by the C-shaped portion of the support; and a holding bar having distal ends with ramp surfaces thereon, this bar can be received in the C-shaped portion of the bra and extends through the space between the tubular elements, with the surfaces of the ramp in engagement with the tubular elements; wherein the thrust of the bar against the tubular elements, causes these tubular elements to be subjected to support. 13. The adjustment mechanism, according to the claim 12, in which the adjustment rod is provided with an internal thread and a bolt can cooperate with this thread, to push the rod against the tubular elements. 14. The adjustment mechanism, according to the claim 13, in which a bolt extends through a hole in the bracket, in engagement with the thread of the gripper bar. The adjustment mechanism according to claim 12, in which the clamping rod causes the tubular elements to extend and separate in engagement with the support, when the clamping rod is pushed against the tubular elements. 16. An adjustable height backrest, for a chair, which comprises: a molded backrest support element; a frame, for connecting the backrest support element to the seat of a chair, this frame includes a pair of spaced, parallel tubular elements; a pair of channels, formed in the back support element, these channels have wedge-shaped side walls and are dimensioned and configured to receive the tubular elements; and devices for pushing the tubular elements in engagement with the side walls of the backrest support element, for securing these tubular elements to the backrest support element. The height adjustable backrest according to claim 16, wherein the frame further includes a plate connecting the pair of tubular elements. 18. The adjustable height backrest according to claim 17, wherein the plate is provided with a vertical slot. The height adjustable backrest according to claim 18, wherein a bolt extends through the slot and into a threaded recess of the backrest support element, to maintain the tubular elements within the channels. The adjustable height backrest according to claim 16, further including a cover for covering the channels in the back support element. The adjustable height backrest according to claim 20, wherein the cover has a tongue that can cooperate with a groove in the backrest support element to retain the cover in a fixed arrangement on the backrest support element. 22. The adjustable height backrest according to claim 20, wherein the tubular elements exit the back of the chair along a bottom edge of the cover.