Information
-
Patent Grant
-
6375257
-
Patent Number
6,375,257
-
Date Filed
Monday, June 12, 200024 years ago
-
Date Issued
Tuesday, April 23, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Maginot, Moore & Bowman, LLP
-
CPC
-
US Classifications
Field of Search
US
- 297 160
- 297 161
- 297 162
- 297 170
- 297 171
- 297 172
- 297 173
- 248 2184
- 248 2273
- 248 2781
- 248 2841
- 248 1832
-
International Classifications
-
Abstract
A tablet arm apparatus providing a re-positionable and stowable tablet work surface which is easily mounted on a chair or integrated into a chair design is described in which movement in each axis is independent and is accomplished by an articulating arm assembly or a single inexpensive two-axis hub.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a tablet arm for furniture, particularly a chair. More specifically, the invention concerns a work tablet that mounts to a chair and uses an assembly having two or more degrees of freedom to pivot and rotate the tablet from a vertical stowed position at the side of the chair to an deployed position above and parallel to the seat of the chair.
A number of chair tablet designs have a mechanism that support the work tablet in a first horizontal position over the chair seat and in a second stowed position when the tablet is not in use. However, few designs have provided an apparatus that can be integrated into the chair design and that allow repositioning of the tablet from above the chair seat to a position to the side of the chair by both rotating the tablet from the horizontal plane to the vertical plane or, when the tablet is in use, by merely swinging the tablet in the horizontal plane. Further, as an easily mountable accessory to a chair, none of the existing tablet designs provide rotation of the tablet from the horizontal plane to the vertical plane and independent rotation in the vertical plane to a stowed position along the side of the chair using a single inexpensive two-axis hub.
One design that provides a horizontal tablet position above a chair and repositions to a stowed vertical position at the side of the chair is Bauman et al., U.S. Pat. No. 5,683,136. The tablet must be pivoted from the horizontal to the vertical plane using one pivot joint then slid to a position along the side of the chair using a slide mechanism. This design does not allow repositioning of the tablet without rotating it from the horizontal plane, nor does it allow the tablet to be rotated within the horizontal plane.
Two designs that use angled pivot joints for positioning are Benoit, U.S. Pat. No. 4,216,994, and Phoon, U.S. Pat. No. 5,845,964. The angled pivot joints cause the tablet to be rotated through the horizontal and vertical planes simultaneously. Other designs, such as the patent to Sorenson, U.S. Pat. No. 5,765,911, allow motion in one plane independent of the other and movement of the tablet without upsetting its horizontal position. However, such designs require manual loosening and re-tightening of friction brakes before and after repositioning.
The alternative design of Kanigowski, U.S. Pat. No. 4,852,940, provides multiple axis motion using a single ball-joint, but fails to provide integral stops or locks. In order to maintain a horizontal position, the chair arms or a shelf extending from them must support the tablet. A design patent to Best, U.S. Pat. No. 409,860,illustrates a mountable accessory, requiring two mounting bars and two single-axis pivot joints to provide repositioning to a stowed position.
In light of the shortcomings of these prior devices, there remains a need for a tablet arm apparatus that allows the tablet to rotate to a vertical position or to move through the horizontal plane without upsetting the other plane of motion and without having to fully stow the tablet for a person to enter or exit of the seat of the chair while requiring only one mount and one inexpensive two-axis joint and furthermore, not requiring manual friction brakes to lock an axis of motion of the tablet.
SUMMARY OF THE INVENTION
Briefly describing one aspect of the invention, the work tablet arm apparatus includes a tablet plate for mounting a work tablet and an articulating arm assembly providing various tablet positions and configured for attachment of the apparatus to a chair.
The difficulties with prior chair tablet arm apparatuses are overcome in one aspect of the current invention by the articulating arm assembly. The arm assembly in one embodiment includes a pivot rod assembly connecting one end of a long arm to one end of a short arm. The other end of the long arm can be rotationally connected to the tablet plate using a slotted washer and stop pin combination that allows limited rotation of the tablet independent of the arm position. The other end of the short arm can be pivotably mounted to the chair arm, preferably as an integral element of the chair design. In one aspect of this embodiment, the short arm pivot provides a means for moving the tablet from a position over the seat of the chair to the front of or other side of the arm of the chair. This pivot allows a person to enter or exit the seat without having to fully stow the tablet and without upsetting the contents of the tablet.
In a further aspect, the pivot rod assembly provides a means for rotating the tablet and long arm about an axis parallel with the chair seat. The pivot rod assembly can include a bias spring for engaging a locking pin into a locking notch, stopping rotation of the long arm when the tablet is parallel to the chair seat. The long arm rotation about the pivot rod provides for quick movement of the tablet when it is not in use. When combined with a pivot to the outside of the arm of the chair, the long arm also provides for stowing the tablet in a vertical position along the outside of the arm of the chair. The chair tablet arm apparatus requires no manual friction brakes and no external support of the tablet other than a single mounting point.
In another embodiment of the invention a chair tablet arm apparatus is provided as an accessory to an existing chair design and is capable of two-axis motion using a single inexpensive hub and a single mounting bracket. The chair tablet arm apparatus in this embodiment can include a tablet plate, a pivot hub assembly, a mounting bar, and a mounting bracket. The mounting bracket can function to attach the apparatus to an existing member of the chair such as a chair leg. The mounting bar rotationally attaches the mounting sleeve to the pivot hub assembly. The pivot hub can be pivotably attached to the tablet plate.
The pivot hub assembly can include spring-biased pins that engage the mounting bar, and are operable to stop rotation of the hub around the mounting bar when the tablet is at a rotational position for pivoting. The tablet plate can then pivot between a position perpendicular to a position parallel to the chair seat. In the perpendicular position, the tablet can rotate independently within the perpendicular plane to a stowed position at the outside of the chair member to which the apparatus is attached.
One object of the invention is to provide a stowable tablet arm apparatus that can be readily integrated into an existing chair using a single mounting point. Another object is to such a tablet arm apparatus that can provide two-axis motion using a single inexpensive joint.
One benefit is that the tablet can be rotated to a vertical position or moved through the horizontal plane without upsetting the other plane of motion and without having to fully stow the tablet for a person to enter or exit the seat of the chair. Another benefit is that the apparatus requires no manual friction brakes to lock an axis of motion of the tablet.
These and other objects, advantages, and features are accomplished according to the devices, assemblies, and methods of the present invention.
DESCRIPTION OF THE FIGURES
FIG. 1
is a perspective view of a chair tablet arm apparatus according to one embodiment of the invention, utilizing a single pivot hub assembly and shown in a deployed position.
FIG. 2
is a front elevational view of the chair tablet arm apparatus depicted in FIG.
1
.
FIG. 3
is a top view of the chair tablet arm apparatus depicted in FIG.
1
.
FIG. 4
is a perspective view of the chair tablet arm apparatus of
FIG. 1
mounted on a chair and in a deployed position.
FIG. 5
is a perspective view of the chair tablet arm apparatus depicted in
FIG. 1
but shown in a stowed position.
FIG. 6
is a top perspective view of a chair tablet arm apparatus according to a further embodiment of the invention, utilizing an articulating arm assembly.
FIG. 7
is a front elevational view of the chair tablet arm apparatus shown in
FIG. 6
but integrated into a chair design and shown in a stowed position at the outside of the chair arm.
FIG. 8
is a top plan view of a chair tablet arm apparatus shown in
FIG. 6
, but integrated into a chair design and shown in a deployed position at the outside of the chair arm and in a deployed position above the chair seat.
FIG. 9
is a perspective view of a chair tablet arm apparatus shown in
FIG. 6
but integrated into a chair design and with the tablet in a deployed position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. The invention includes any alterations and further modifications in the illustrated devices and described methods and further applications of the principles of the invention which would normally occur to one skilled in the art to which the invention relates.
The present invention relates to a tablet arm apparatus for furniture, particularly a chair. More specifically, the invention concerns a work tablet that mounts to a chair and uses an assembly having two or more degrees of freedom to pivot and rotate the tablet from a vertical stowed position at the side of the chair to a deployed position above and parallel to the seat of the chair.
In accordance with one embodiment of the present invention, a chair tablet arm apparatus
10
is shown in FIG.
1
and as attached to a chair in FIG.
4
. The apparatus
10
contemplates a tablet plate
11
pivotably attached to a pivot hub assembly
16
, which is itself rotationally attached to a mounting bar
20
. The apparatus
10
can be generally constructed of plastic or lightweight metal and can be attached to a member of a chair, such as a chair leg, with a mounting bracket
27
as depicted in FIG.
4
. The apparatus is movable from a deployed position
10
″ (
FIG. 4
) above and parallel to the seat of the chair, and a vertical stowed position
10
′ at the side of the chair as depicted in FIG.
5
. The stowed position
10
′ facilitates easy access to or exit from the seat of the chair. The deployed position
10
″ provides a work surface functional to a person seated in the chair.
Referring to
FIGS. 1 and 2
, the mounting bracket
27
in one specific embodiment preferably includes two opposing “C” clamp portions
28
and
29
. Each clamp portion
28
and
29
defines a curved portion
28
a
and
29
a
forming a half cylinder, and a flat flange
28
b
and
29
b
extending the length of one end of the cylinder. The flange
28
b
of clamp portion
28
is attached to a long arm
21
of the mounting bar
20
, preferably at three weld points
32
. The apparatus
10
can be mounted to a chair leg, as depicted in
FIG. 4
, by first positioning the clamp portion
28
with the half cylinder
28
a
in contact with one side of the chair leg. The second clamp portion
29
is then placed in juxtaposed mirror image fashion so that the two half cylinders
28
a
and
29
a
cooperate to enclose the chair leg. Three alignment dimples
31
defined between the two flanges
28
b
and
29
b
align the clamp portions and the portions are drawn together by a number of screws
33
. The screws
33
and dimples
31
cooperate to allow the clamp portions
28
and
29
to firmly grip the chair leg. The interior of the half cylinder portions
28
a
and
29
a
of each clamp
28
and
29
is preferably lined with foam tape
30
to provide a firm attachment to the chair member
34
.
The mounting bar
20
extends from a long arm
21
through a 90-degree bend
23
to a short arm
22
. The pivot hub assembly
16
can include a bearing hub
17
, a retaining nut
19
, a rest bracket
24
, and a washer
25
. The hub assembly
16
is rotationally mounted on the short arm
22
of the mounting bar
20
, with the end
22
passing through a central opening
18
(
FIG. 3
) of the hub
17
. The retaining nut
19
, which is preferably a cap nut, can be attached to the short arm
22
of the mounting bar to trap the hub
17
between the retaining nut
19
and the washer
25
and rest bracket
24
. The rest bracket
24
is preferably fixed to the short arm
22
, such as at weld points
26
. The washer
25
provides a sliding surface for the hub
17
relative to the rest bracket
24
. In the deployed position
10
″ depicted in
FIG. 2
, the tablet plate
11
is supported by the rest bracket
24
in a generally horizontal attitude.
Referring to
FIG. 1
, the tablet plate
11
has a flat surface having multiple mounting holes
12
defined therethrough by which a solid work surface may be attached. The plate further includes a pair of mounting ears
13
forming a U-shape extend from one end thereof. The mounting ears
13
are spaced apart to receive the pivot hub
17
within the U-shape.
Each mounting ear
13
defines a co-linear thru-hole
14
. The thru-holes are sized to receive a corresponding spring pin
15
therein, with each pin extending toward the interior of the U-shape. The spring pins
15
can extend through opposite walls
17
a
and
17
b
of the hub
17
, as depicted in
FIG. 3
, to mount the tablet plate
11
to the hub for rotation therewith. At a rotational position in which the tablet plate
11
is in a plane sharing one axis with the chair seat, the spring pins
15
can engage detents
35
defined on opposite sides of the short arm
22
of mounting bar
20
. The detents
35
cooperate with the ends of the pins
15
to resist rotation of the hub
17
and tablet plate when the pins reside within the detents. However, the spring pins are configured to allow the ends of the pins to slide out of the detents upon application of a moderate force rotating the hub
17
relative to the short arm
22
. The tablet plate
11
remains free to pivot about the axis of the spring pins
15
, and relative to the hub, permitting movement of the tablet plate between a horizontal and vertical position.
The hub
17
is preferably formed substantially entirely of nylon or a similar low-friction material. Most importantly, the hub opening
18
must have a low friction characteristic so that the hub, and therefor the tablet plate
11
, can freely rotate about the mounting bar. Likewise, the pin bores
16
a
and
16
b
must have a low friction characteristic so that the spring pins can pivot freely as the tablet plate is pivoted relative to the hub. In addition, the spring pins must be able to freely translate axially toward the detents
35
in the mounting bar.
The operation of the chair tablet arm assembly
50
is as follows. The stowed position
10
′ depicted in
FIG. 5
presents a well-situated location for the tablet when it is not in use. In the stowed position
10
′, the tablet plate
11
is oriented in a vertical position, perpendicular to the chair seat. The tablet plate mounting ears
13
are located at the top-most end of the tablet plate, which hangs from the pivot pins
15
. To re-position the tablet plate to the deployed position
10
″ depicted in
FIG. 4
, two steps are required. First, the tablet plate
11
is rotated within the vertical plane, rotating the hub
17
about the short arm
22
of the mounting bar
20
. At 180-degrees of rotation, the rotation position at which the mounting ears
13
are located at the bottom-most end of the tablet plate, the spring pins
15
engage the detent bores
35
on the mounting bar
20
, resisting further rotation. Second, the tablet plate
11
is pivoted about the pivot pins
15
from the vertical position toward the chair seat until the tablet plate contacts and is supported by the rest bracket
24
in the deployed position
10
″ depicted in FIG.
2
. Completion of the steps and movement of the tablet plate
11
in reverse order will return the tablet plate to the stowed position
10
′ depicted in FIG.
5
.
In a further embodiment of the invention, as depicted in
FIG. 6
, a tablet arm apparatus
50
contemplates a tablet plate
51
rotationally attached to an articulating arm assembly
81
. The assembly includes a slotted washer
53
, a long arm
61
, a pivot rod assembly
65
, and a short arm
77
. The apparatus
50
can be generally constructed of plastic or lightweight metal and can be attached to a member of a chair with the short arm
77
, preferably as an integral part of the chair design. The vertical stowed position
50
′ of the apparatus, at the side of the chair, is depicted in
FIG. 7. A
first deployed position
50
″ of the apparatus with tablet plate
51
parallel to the seat of the chair and to the outside of the arm of the chair is depicted in
FIG. 8. A
second deployed position
50
′″ above and parallel to the seat of the chair is further depicted in FIG.
8
. The first deployed position
50
″ and stowed position
50
′ facilitate access to or exit from the seat of the chair. The first and second deployed positions
50
″ and
50
′″ each provide a work surface functional to a person seated in the chair.
Referring to
FIG. 6
, the short arm
77
is pivotally mounted at one end
77
b
to the chair arm
58
. The other end
77
a
of the short arm
77
is attached to the pivot sleeve
69
of a pivot rod assembly
65
. One end
61
a
of the long arm
61
can be attached to a pivot rod
66
of the pivot rod assembly
65
. The pivot rod assembly
65
provides a means for the ends
61
a
and
77
b
of the arms
61
and
77
, respectively, which are not attached to pivot rod assembly, to articulate from a position extended and opposite each other, as depicted in
FIG. 6
, to a position toward each other, as depicted in FIG.
7
. The articulating translation allows tablet plate
51
to be rotated from the stowed position
50
′ depicted in
FIG. 7
to the first deployed position
50
″ along the outside of the chair arm
58
, depicted in FIG.
8
. The pivotable mounting of the short arm
77
, permits the entire tablet arm assembly
50
to pivot between the two deployed positions
50
″ to
50
′″, both depicted in FIG.
8
.
Referring to
FIG. 6
, the short arm
77
can be constructed of a section of rectangular tubing. The rectangular shape forms two wider sides
77
c
and
77
d
and two narrower sides
77
e
and
77
f.
Two thru-holes
78
are bored in the wider sides
77
c
and
77
d,
near one end
77
b,
to provide means for pivotably mounting the short arm
77
to a member
58
of the chair (FIG.
8
). At the same end
77
b
of the short arm
77
an end cap
80
in inserted to close the open tubing end. The opposite end
77
a
of the short arm
77
is preferably cut at an angle and is attached to pivot sleeve
69
of the pivot rod assembly
65
.
The pivot rod assembly
65
includes the pivot rod
66
and pivot sleeve
69
, as well as a locking spring
72
, a washer
73
, and a retaining nut
74
. The pivot rod assembly
65
provides a means for the pivot rod
66
to rotate relative to the pivot sleeve
69
and for the resulting articulation of the attached short arm
77
and the attached long arm
61
to stop when the arm assembly is in the extended position depicted in FIG.
6
. The cylindrical pivot rod
66
can have an end
66
a
attached to the angled end
61
a
of the long arm
61
. The pivot rod
66
extends through the open cylinder formed by the pivot sleeve
69
with each end
66
a
and
66
b
situated beyond the respective end of the pivot sleeve.
In the preferred embodiment, a locking pin
75
extends through a hole
67
bored through a midpoint along the pivot rod
66
, with the pin
75
situated adjacent end
69
a
of the pivot sleeve. The pivot rod
66
further includes an opposite threaded end
68
configured for receiving the retaining nut
74
. The nut is used to secure the washer
73
and locking spring
72
between the retaining nut
74
and the end
69
b
of the pivot sleeve
69
. In this arrangement, the locking spring
72
biases the pivot rod
66
toward the end
69
b
of the pivot sleeve. More specifically, the locking spring biases the pivot rod
66
so that the locking pin
75
can reside within notches
70
and
71
cut in oppose sides of the end
69
a
of the pivot sleeve
69
, as shown in FIG.
6
. When the locking pin
75
is so situated, the long arm
61
is fixed against rotation relative to the pivot sleeve
69
. Rotation is permitted when the pivot rod
66
is pushed toward end
69
a
of the sleeve
69
, against the force of the locking spring
72
, to thereby release the locking pin
75
from the notches
70
and
71
.
The long arm
61
can be constructed of a section of rectangular tubing of the same type as the short arm
77
. One end
61
a
of the long arm
61
is angled and attached to an end
66
a
of the pivot rod
66
. The other end
61
b
of the long arm
61
can be rotationally connected to the tablet plate
51
using rotational pin
59
, support disk
56
, a slotted washer
53
, and stop pin
55
. The long arm
61
can have an end cap
62
enclosing the tube end near the tablet plate
51
.
The arm
61
can define a thru-hole
63
sized to receive the rotational pin
59
therethrough. The pin
59
is preferably affixed to the underside of the tablet plate
51
, such as by press-fit into a corresponding bore in the plate. Most preferably, the pin passes through a support disk
56
interposed between the tablet plate
51
and the long arm
61
, and then through the hole
63
in the arm
61
. A retaining cap
64
can engage the pin
59
to fasten the rotational pin, while permitting the pin to rotate relative to the arm
61
.
In a further feature of this embodiment, the slotted washer
53
is preferably mounted to the long arm
61
, with the support disk
56
disposed between the washer
53
and the tablet plate
51
. The washer
53
defines a slot
54
along an arc of a constant radius and extending for less than 360-degrees around the washer. The slotted washer
53
is configured to cooperate with a stop pin
55
extending from the underside of the tablet plate
51
. In other words, the stop pin
55
rides within the slot
54
of the washer to control the range of rotational movement of the tablet plate
51
relative to the long arm
61
. Preferably, the slot
54
extends along an arc of about 135-degrees so that the user can find a comfortable orientation of the tablet plate in use. The tablet plate
51
can define multiple mounting holes
52
therethrough by which a work surface can be attached.
The operation of the chair tablet articulating arm assembly
50
is as follows. The stowed position
50
′ depicted in
FIG. 7
presents a well-situated location for the tablet when it is not in use. In the stowed position
50
′, the tablet plate
51
can be oriented in a vertical position, perpendicular to the chair seat. To re-position the tablet plate
51
to the first deployed position
50
″, depicted in
FIG. 8
, the tablet plate can be translated to the horizontal position, parallel to the chair seat, by the pivoting of the long arm
61
at the pivot rod assembly
65
, until the locking pin
75
engages the locking notches
70
and
71
. The tablet plate
51
is thereby located outside the chair arm
58
, at position
50
″ depicted in FIG.
8
.
To re-position the tablet plate
51
over the seat of the chair, such as in the second deployed position
50
′″ depicted in
FIG. 8
, the entire arm assembly can be simply rotated about the pivotable mounting fastener
79
located near the end of short arm
77
. Completion of the steps and movement of the assembly in reverse order can return the tablet plate to the stowed position
50
′ depicted in FIG.
7
.
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character. It should be understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.
Claims
- 1. A tablet arm apparatus for supporting a work surface on an article of furniture, the apparatus comprising:a mounting bar having a first arm and a substantially perpendicularly disposed second arm; a clamp having a portion attached to said second arm and configured to engage a member of the article of furniture to support said tablet arm apparatus thereon; a pivot hub rotatably mounted on said first arm of said mounting bar; a tablet plate configured for supporting the work surface and including at least one mounting ear; and means for pivotably attaching said at least one mounting ear to said pivot hub to permit pivoting of said tablet plate relative to said pivot hub, whereby said tablet plate is also rotatable with said pivot hub relative to said mounting bar.
- 2. The tablet arm apparatus according to claim 1, wherein:said tablet plate includes two mounting ears defining a U-shape opening to receive said pivot hub therebetween; and said means for pivotably attaching includes; a pair of pin bores defined in said pivot hub at opposite sides thereof; and a pair of pins, one each projecting from a corresponding one of said two mounting ears and pivotably disposed within a corresponding one of said pair of pin bores.
- 3. The tablet arm apparatus according to claim 2, wherein:said pivot hub defines a central opening therethrough for rotatably mounting said pivot hub on said first arm; said pin bores intersect said central opening; said first arm of said mounting bar defines at least a pair of oppositely disposed detents; and said pins are spring pins configured for spring biased engagement within a corresponding one of said detents when said tablet plate and pivot hub are rotated to a position in which said pins are aligned with said detents.
- 4. The tablet arm apparatus according to claim 1, wherein said clamp includes:a first C-clamp portion attached to said second arm and defining a first cylinder portion; a second C-clamp portion defining a second cylinder portion, whereby said first and second cylinder portions can be juxtaposed about the member of the article of furniture; and a number of fasteners for clamping said first and second C-clamp portions together with said first and second cylinder portions engaged about the member of the article of furniture.
- 5. The tablet arm apparatus according to claim 1, further comprising a rest bracket mounted on said first arm adjacent said pivot hub, said rest bracket defining a surface for supporting said tablet plate when said plate is in a deployed position.
- 6. The tablet arm apparatus according to claim 1, wherein said pivot hub is composed of a low-friction material.
- 7. A tablet arm apparatus for supporting a work surface on an article of furniture, the apparatus comprising:a first arm having a first end and an opposite second end, said second end defining means for pivotably mounting said first arm to the article of furniture; a second arm having a first end and an opposite second end; a tablet plate mounted to said second end of said second arm; a pivot rod assembly including a pivot sleeve and a pivot rod rotatably disposed within said pivot sleeve, wherein the first end of one of said first arm and said second arm is connected to said pivot sleeve, and the first end of the other of said first arm and said second arm is connected to said pivot rod; wherein at least one notch is defined at one end of said pivot sleeve; and wherein a locking pin is mounted on said pivot rod and is configured to be received within said at least one notch to prevent relative rotation between said pivot rod and said pivot sleeve.
- 8. The tablet arm apparatus according to claim 7, wherein:said pivot rod has a first and an opposite second end, with said locking pin disposed adjacent to said first end of said pivot rod and said one end of said pivot sleeve; said pivot rod being rotatably and slidably disposed within said pivot sleeve; and said pivot rod assembly further includes a biasing spring acting between said second end of said pivot rod and an end of said pivot sleeve opposite said one end and operable to bias said locking pin into said at least one notch when said pivot rod is rotated relative to said pivot sleeve to a position in which said locking pin is aligned with said at least one notch.
- 9. A tablet arm apparatus for supporting a work surface on an article of furniture, the apparatus comprising:a first arm having a first end and an opposite second end, said second end defining means for pivotably mounting said first arm to the article of furniture; a second arm having a first end and an opposite second end; a tablet plate mounted to said second end of said second arm; a pivot rod assembly including a pivot sleeve and a pivot rod rotatably disposed within said pivot sleeve, wherein the first end of one of said first arm and said second arm is connected to said pivot sleeve, and the first end of the other of said first arm and said second arm is connected to said pivot rod; a washer affixed to said second end of said second arm, said washer defining an arcuate slot therein; means for rotatably fastening said tablet plate to said second end of said second arm; and a stop pin projecting from said tablet plate and into said arcuate slot, whereby said arcuate slot limits the range of rotation of said tablet plate relative to said second arm.
US Referenced Citations (15)