US 3353866 A
Description (OCR text may contain errors)
Nov. 21, 1967 H. D. CHAPMAN ET AL. 3,353,866
SEATING UNIT Filed Aug. 22, 1966 2 Sheets-Sheet 1 M 25 72 m 74 6 4 4 2 7 JV/ I NVENTORS Q CHAPMAN Havey 67 54AM? BY aqzdmm,QMMQTMgmmmmmm s H. D. CHAPMAN ET AL 3,353,866
Nov. 21, 1967 SEATING UNIT 2 Sheets-Sheet 2 Filed Aug. 22, 1966 nvvlv'roks flak/A20 Q CHA Aka/er a 5ANK 5r ja wm, Qudakz,
United States Patent 3,353,866 SEATING UNIT Howard D. Chapman, Highland Park, and Henry C. Banke, Chicago, Ill., assignors to Clarin Mfg. Co., Chicago, Ill., a corporation of Illinois Filed Aug. 22, 1966, Ser. No. 574,077 4 Claims. (Cl. 297-162) ABSTRACT OF THE DISCLOSURE A tablet arm assembly adapted to be supported adjacent a seating unit and having a tablet arm movable between an operative and an inoperative position incident to pivotal movement about a first generally horizontal axisextending generally from front to rear of the seating unit and a second axis extending generally normal to the plane of the tablet arm.
The present invention relates generally to seating units and, more particularly, to seating units having mounted thereon a tablet arm movable between'an operative and an out-of-the-way position.
Insofar as seating in classrooms, lecture rooms and the like is concerned, it is conventional to provide chairs having a tablet arm along one side which provides a writing surface for the, occupant of the chair. In the majority of instances, the writing surface is relatively small, typically being only slightly larger than a letter-size piece of writing paper.
It is also conventional to mount the tablet arm adjacent the chair in such a'manner that it can be collapsed or folded from an operative position in which it provides a writing surface to an out-of-the-way or storage position at the side of the chair. In certain well-known chair constructions, the tablet arm in the collapsed or folded position hangs generally vertically downwardly from a point of attachment adjacent the backrest of the chair, with that portion of the tablet arm defining the writing surface extending forwardly to a point approximately even with the front leg of the chair.
It is frequently desirable to provide a tablet arm which defines a writing surface significantly larger than that provided by the conventional tablet arm, e.g., a surface which extends essentially across the entire front of the chair. With a tablet arm of such size, the conventional manner of mounting the arm and folding it into the storage position is not entirely satisfactory since the size of the tablet arm causes it to project past the front'of the chair where it interferes with traffic moving past the chair.
Also, it is a disadvantage in conventional tablet arm chairs that the tablet arm provides the only arm rest at one side of the chair so that, when the tablet arm is collapsed, there is no arm rest for the occupant of the chair.
Finally, most tablet arms are mounted so as to move downwardly into the collapsed position. However, tablet arms are normally made of wood and are relatively heavy. This is particularly true of large size tablet arms. There is a tendency, therefore, for a user to allow the tablet arm to drop into its collapsed position and, in so doing, to place a significant structural strain on the chair and the mounting.
The main objects of the present invention are to provide a seating unit having an improved movable arm assembly; to provide an improved means for mounting a large tablet arm on a chair so as to permit the arm to be moved between an operative position and an out-ofthe-way storage position; to provide a seating unit having-'an-arm assembly movable between a position in which it provides a writing surface and another position in which it provides only an arm rest, in accordance with the needs of the user; and to provide a seating unit which includes an arm assembly movable between given positions and means for controlling such movement.
Other objects and advantages will become apparent from the following detailed description and the accompanying drawings wherein:
FIGURE 1 is a perspective view of a seating unit showing various features of the present invention, with two positions of an arm assembly of the seating unit being illustrated in full line and in phantom respectively;
FIGURE 2 is an enlarged perspective view of a portion of the arm assembly of FIGURE 1 in a position intermediate the positions illustrated in FIGURE 1;
FIGURE 3 is an enlarged sectional view taken along line 33 of FIGURE 1;
FIGURE 4 is an enlarged perspective view of the arm assembly of FIGURE 1 in an intermediate position different from that shown in FIGURE 2;
FIGURE 5 is a view taken generally along the line 55 of FIGURE 4; and
FIGURE 6 is a view taken generally along line 66 of FIGURE 4.
Very generally, the present invention is directed to a tablet arm assembly adapted to be supported adjacent a seating unit. The tablet arm of the assembly is movable between an operative and an inoperative position incident to pivotal movement about a first generally horizontal axis extending generally from front to rear of the seating unit and about a second axis extending generally normal to the plane'of the tablet arm.
Referring to the drawings, there is illustrated a seating unit 10 provided with an arm assembly 12. The seatingunit 10 includes a body-supporting shell 14 which may be molded from a suitable material such as a fiber-reinforced resin or the like to define a seat portion 16 and a backrest 18. The shell 14 is suitably mounted on a pedestal 20 which includes a generally vertically supported post 22 aflixed to a base 24 which may be suitably secured to a floor or the like.
The arm assembly 12 generally includes a frame 26 suitably secured to the pedestal 20. A tablet arm 28 is provided which includes a large writing surface 29 which extends across substantially the entire front of the seat 1 16, and a neck 29a extending rearwardly from the writing surface along that side of the seat which is to the right of an occupant of the seat. The tablet arm is pivotally and rotatably mounted on the frame for movement between an operative position, as shown in full lines in FIGURE 1, and an out-of-the-way position, as shown in phantom in FIGURE 1. An arm rest 30'is also secured to the frame 26 (FIG. 2)and is moved from an ineffective to a usable position when the tablet arm 28 moves from the operative to the out-of-the-way position.
In moving the tablet arm from the operative to the outof-the-way position, it is first rotated about a substantially horizontal axis extending generally parallel to the side of the seat 16 of the shell 14. That is, the tablet arm is rotated about a horizontal axis which lies in a vertical plane generally normal to the front edge of the seat 16. This movement brings the arm rest 30 into the usable position. The tablet arm is then pivoted about a second horizontal axis normal to the plane of the tablet arm to the out-of-the-way or storage position.
More particularly, the frame 26 is secured to the pedestal 20 by means of a bracket which includes a generally horizontally disposed brace 32 extending from the post 22 of the pedestal toward the right hand side of the seat 16. The outer end of the brace is provided with a depending vertically disposed plate 34, the upper edge of 3 which defines a ledge upon which the frame 26 is supported (FIG. I). The frame 26 includes a plate 36 which defines a downwardly facing shoulder, and which is secured to the plate 34 of the bracket by bolts 38 with the shoulder resting upon the ledge of the plate 34.
The frame 26' also includes a pair of struts 4'0 and 42 which extend upwardly from the plate 36 and to the upper ends of which the tablet arm 28 and arm rest 30 are mounted. The strut 40' is generally vertically disposed ad'ja-cent the rear of the plate 36 while the strut 42 extends forwardly as well as upwardly from the forward edge of the plate so as to locate the upper ends of the struts in horizontally spaced relation to each other above the elevation of the seat 16 of the shell 14. An ear 4 1 projects upwardly from the upper end of the strut 42 (FIG. 2) and forms part of a locking device for limiting shifting movement oft'he tablet arm 28' when in the operative position. A cross bar 43 extends between the struts adjacent the upper ends thereof to increase the rigidity of'theframe.
In order to effect connection between the frame 26' and the tablet arm 28, a hinge plate or bracket 44 is mounted on the upper ends of the struts 4t) and 42 for hinged movement about a horizontal axis as defined by a pair of bolts 46. The plate 44- is of a generally rectangular configuration and is provided with an integral peripheral flange 48 which projects outwardly adjacent each of its edge (FIG. 4). Those portions 50 of the flange adjacent each of the end edges of the plate are of sufficient size to receive and retain the bolts 46 by means of which the plate issecured to the struts of the frame 26. e edges of the flange are tapered somewhat to provide a surface which engages the crossbar 43 to limit the pivotal movement of the plate 44.
That portion of the flange which is uppermost (FIG- 2) or facing the seat 16 (FIG. 3), depending upon the pivoted position of the hinge plate 44, is somewhat U- sha-ped' in that it is provided with a relatively wide center portion 52" and outward extensions 54 thereof at each end; (FIG; 4). These portions of theflange 48* serve to support the arm rest 30 which is in the form of an elongated pad having an upper surface which is slightly concave when viewed in transverse cross section. Thus, the arm rest 30 is movable bet-ween an out-of-the-way ineffective position (FIG. 2) in which it faces the body of the occupant of the chair, and? a usable position (FIG. 4), in which it faces upwardly. As will become apparent, the tablet. arm 28 occupies positions functionally opposite tothose occupied by the arm rest- 30, being in the operative position when the arm: rest is in the out-of-the-way position and being in the out-of-the-way position. when the arm rest is in the usable position- Thus, the occupant. of the chair has either the arm rest or the tablet arm available for use depending upon the position of. the arm assembly;
In order to facilitate attachment of. the tablet arm 28 to the hinge plate: 44;-v in a: manner hereinafter described, the plate is provided with. an opening 56 of circular configuration (FIG. 6) which. is. located on the. longitudinal axis of the hinge plate but. oft-center in the direction of the: strut 42 of. the frame- 26; In: addition, the surface of the plate adjacent to which: the' tablet arm is secured is machined to provide an: arcuate flat 58 near the end of the plate adjacent the strut 42,. and is also machined to provide an annular flat 60 concentric with the opening 56. These flats are engaged by buttons 62' of a swivel plate 64 secured to the hinge plate 44, as hereinafter described. Finally, apost- 65 projects inwardly from the inner surface of the plate and cooperates with other portions of the arm: assembly to limit rotational movement of the tablet arm,
The tablet arm 28 is mounted on the hinge plate 44 for swiveling movement about an axis normal to both the plane of the hinge plate and the plane of the tablet arm. In this regard, the swivel plate 64, previously referred to, is secured to the under surface of the tablet arm by means of fasteners 66. The swivel plate is of a generally rectangular configuration but is rounded at one end, and includes a continuous peripheral flange 67, the outer edge of which engages the tablet arm. The main body portion of the swivel plate is thusspaced from the surface of the tablet arm, as seen: in. FIGURE 3, by the width of the flange 6'7".v
The swivel plate 64 is attached tothe hinge plate 44 by a threaded shaft or bolt 68 which is flattened on two sides and which includes a head 70 which is welded to the inner or concealed surface of the swivel plate (FIG. 2). The bolt isreceived withinv a circular opening 74 which is located on the longitudinal centerl'ine of the swivel plate 64 but which is offset somewhat in the direction of the strut 42. The bolt is held in place by a nut 75. The welding of' the bolt 68' to the swivel plate precludes rotation of the bolt relative to the swivel plate. The bolt is' free to rotate, however, within the opening 56 of the hinge plate 44 relative to the hinge plate by virtue of the chcular configuration of that opening. Accordingly,- when the tablet arm rotates, the swivel plate 64 and bolt 68 rotate as well, but the hinge plate remains stationary.
It is desirable that the degree of rotational movement of the tablet arm about the axis defined by the bolt 68 be limited- It is also desirable that the speed of movement of the tablet arm to the out-of-the-way' position be controlled. so as to prevent damage to the. arm assembly incident to the rapid movement. of the tablet arm to such position. Both of these functions area'ccomplish'ed through the provision. of a stop plate 76 and coil spring 78, as hereinafter described.
More. particularly, the stop plate 76, seen best in FIG- URES 4 and 6, is formed to provide an arcuate outer edge portion 80 of a given radius which defines approximately one-half the periphery of the plate", and an arcuate edge portion 82 of a substantially lesser radius which defines. the remainder of the periphery of the plate. The arcuate" edges are interconnected by radially directed fl'a't edges" which provide a pair of generally diametrically opposedshoulders 84'. The plate includes a central opening. 86 which is" noncircular like the opening 74 of. the swivelplate 64 andincl'udes fiat side edges, as seenv in phantom in FIGURE 6. The opening 86 receives the outer .en'd'v portion of the flattened bolt 68 and, because of the shape of the bolt and. opening, th stop plate is keyed to the bolt and rotates therewith. The stop plate 76. is retained on the bolt by a nut 86. After a given degree of rotation: of the stop plate in either direction, the shoulders 84: engage the post 65; preventing further rotation of the stop plate and, hence, the bolt and tablet arm as well. The relative dispositions of the stop plate and post are such as to-limit the tablet armtorotational movement between the'two positionsshown in FIGURES 2 and 4 respectively.
It should be appreciated that as the tablet arm is rotated from the positionzshown. in. FIGURE'Z to the position shown in FIGURE 4, it will pass. an intermediate position in which its center of gravity lies just rearwardly of a line passing vertically through the bolt 68 and that, if released at or slightly rearwardly of that point, it would rapidly accelerate to the position of FIGURE 4 until its movement was arrested by abrupt engagement of the post 65 with one of the: shoulders 84. Accidental release of the tablet arm in such a position is not unlikely, particularly in view of the weight of the arm and in. view of the factthat users may be taken by surprise whenthe center of gravity of the arm shifts suddenly.
To prevent injury to the arm assembly by the rapid movement of the arm and the impact incident to the rapid arrest of this movement, the coil spring 78 is provided in encircling relation to the bolt 68 intermediate the hinge plate 44 and stop plate 76 one end of the spring. engages the post 65 to prevent its rotation in one direction, while the other end of the spring is offset and inserted into an opening 88 in the stop plate so as to cause the spring to be tightened as the stop plate rotates relative to the post. Because of the nature of the spring, the resistance which it offers to the rotational movement of the tablet arm increases with continued rotation of the arm in a clockwise direction as viewed in FIGURE 2, thereby effecting a deceleration of the tablet arm and counteracting the force of gravity tending to accelerate it.
When the tablet arm is in the position of FIGURE 4, its center of gravity is below the rotational axis defined by the bolt 68, a fact which would norm-ally render movement of the tablet arm out of such position somewhat more ditficult. However, the reaction force exerted by the biased coil spring provides assistance in this regard and facilitates such movement. The spring does not provide a brake to the movement of the tablet arm into the position shown in FIGURE 2, but resistance to such movement has not been found to be necessary.
Rotational movement of the swivel plate 64 relative to the hinge plate 44 is facilitated by the buttons 62, previously referred to, which are secured to the surface of the swivel plate adjacent the hinge plate and engage the flats 58 and 60 provided on that plate. The buttons also serve to space the plates 44 and 64 from each other.
Because the tablet arm 28 and swivel plate 64 are mounted on the hinge plate 44 for rotation about the bolt 68, there may be some tendency for the tablet arm to shift or swivel when in the operative position (FIG. 1) so as to interfere with the use of the tablet arm by the occupant of the seating unit. To prevent such movement, the swivel plate is provided with an opening 90 (FIG. 2) which receives the ear 41 of the strut 42 of the frame 26 when the tablet arm is in the operative position. A second opening or groove 92 is provided adjacent the opening 90 to prevent interference between the corner of the strut 42 and the swivel plate 44.
In the use of the chair, the tablet arm may be moved from the operative position shown in full lines in FIG- URE 1 to the out-of-the-way or storage position of that figure by first lifting the outer left hand edge of the tablet arm so as to pivot the arm about the axis defined by the bolts 46 and into the position shown in FIGURE 2. The movement also brings the arm rest 30 into an operative position. The tablet arm is then rotated about the bolt 68 to the position of FIGURE 4. During such rotation, the swivel plate 64, the bolt 68, and the stop plate 76 all rotate while the hinge plate 44 and post 65 remain stationary. Such rotation, which is limited by engagement between a shoulder 84 of the stop plate and the post 65, is increasingly resisted by the biasing efiect of the spring 78, thereby preventing uncontrolled movement of the tablet arm to the o-ut-of-the-way position.
Movement of the tablet arm from the out-of-the-way position to the operative position is accomplished by the reverse of the above steps. During such movement, the spring 78 provides some assistance. Cooperation between the ear 41 of the strut 42 and the opening 90 of the swivel plate prevent shifting movement of the tablet arm in the operative position.
While the present invention has been described with respect to one specific structural embodiment thereof, it should be apparent that various modifications may be made therein without departing from the scope of the invention.
Various features of the invention believed to be novel are set forth in the following claims.
What is claimed is:
1. A tablet arm assembly adapted to be supported adjacent a seating unit and movable between an operative position in which it provides a generally horizontal writing surface and a collapsed out-of-the-way position along side the seating unit, said tablet arm assembly comprising a support positioned at one side of the seating unit, a bracket mounted on said support for hinged movement about a first fixed generally horizontal axis located above the seat of the seating unit and lying in a vertical plane generally normal to the front edge of the seat, a tablet arm having a generally planar writing surface, means securing said tablet arm to said bracket so as to permit hinged movement of said writing surface about said first axis between a generally horizontal and a generally vertical position, said latter-mentioned means including a shaft defining a second axis disposed generally normal to the plane of said writing surface and intersecting said Writing surface adjacent the rearward edge thereof, said tablet arm being rotatable about the axis of said shaft when said writing surface is vertically disposed so as to swing said writing surface rearwardly to a position alongside the seating unit, said shaft being keyed to said tablet arm so as to rotate therewith, and stop means for limiting rotational movement of said tablet arm about said second axis including a plate keyed to said shaft and defining a pair of shoulders, and a member extending outwardly from said bracket and positioned thereon so as to be engaged by said shoulders of said stop means as said tablet arm rotates.
2. A tablet arm assembly .in accordance with claim 1, wherein means are provided to prevent rotational movement of said tablet arm about the axis of said shaft when said tablet arm is in said operative position, said means including an ear projecting from said support, and means defining surfaces fixed relative to said tablet arm positioned so as to receive said ear in close fitting engagement when said tablet arm is in said operative position.
3. A tablet arm assembly in accordance with claim 1, wherein means are provided for braking the rotational movement of said tablet arm about said second axis toward said out-of-the-way position, said braking means providing an increasing resistance to rotational movement as said tablet arm is rotated toward said out-of-the-way position.
4. A tablet arm assembly in accordance with claim 3, wherein a coil spring encircles said shaft, one end of said coil spring being mounted for rotation with said shaft and the other end of said coil spring being secured to said bracket, said coil spring thereby being effective to brake the rotational movement of said tablet arm.
References Cited UNITED STATES PATENTS 955,523 4/1910 Lytle 297-162 1,731,293 10/ 1929 Chapman 297162 2,473,037 6/ 1949 Morgan et a1. 297--162 3,102,754 9/1963 Junkunc 297162 3,140,894 7/1964 Hicke 297-162 3,197,254 7/1965 Hendrickson 297162 JAMES T. MCCALL, Primary Examiner.