U.S. patent application number 12/587507 was filed with the patent office on 2011-04-14 for adjustable height system for wooden legged furniture.
Invention is credited to David Lee Wells.
Application Number | 20110084184 12/587507 |
Document ID | / |
Family ID | 43854080 |
Filed Date | 2011-04-14 |
United States Patent
Application |
20110084184 |
Kind Code |
A1 |
Wells; David Lee |
April 14, 2011 |
Adjustable height system for wooden legged furniture
Abstract
A threaded connection incremental height adjustment system for
furniture having wooden legs that allows vertical alignment of
extensions after tightening for leg extensions that are not
circular in cross-section or are circular in cross-section but have
patterns or designs that are desired to be aligned vertically.
Inventors: |
Wells; David Lee; (Boise,
ID) |
Family ID: |
43854080 |
Appl. No.: |
12/587507 |
Filed: |
October 9, 2009 |
Current U.S.
Class: |
248/188.8 |
Current CPC
Class: |
A47B 91/02 20130101 |
Class at
Publication: |
248/188.8 |
International
Class: |
A47B 91/02 20060101
A47B091/02 |
Claims
1. A threaded connection incremental height adjustment system for
furniture having wooden legs not circular in cross-section that
allows for the vertical alignment of any height extension
cross-section shape.
2. A threaded connection incremental height adjustment system for
furniture having wooden legs that are circular in cross-section
that allows for the vertical alignment of vertical patterns or
designs on each height extension.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM
LISTING COMPACT DISC APPENDIX
[0003] Not Applicable.
BACKGROUND OF THE INVENTION
[0004] The present invention relates, in general, to the
incremental height adjustment of furniture with wooden legs where
the cross-sectional shape of the leg is not circular or where
vertical patterns or designs on circular shapes would require
alignment for visual reasons.
[0005] Prior art discloses threaded connections for incremental
height adjustment in Crue, U.S. Pat. No. 7,278,687 B2 for bar
stools, and in V. M. Winters, U.S. Pat. No. 3,232,253 for
children's chairs. Both are limited to extensions having circular
cross-sections without vertical patterns or designs on the exterior
that would require vertical alignment. This limitation is due to
the lack of a method to align the exterior of each extension piece
while maintaining a tight threaded connection. The consequences of
misaligning non-circular cross-section shapes would be a reduction
in leg strength and unattractiveness.
[0006] Other systems elevate furniture by means of resting the legs
on top of stacked interlocking spacer blocks of various sizes and
shapes as in Robert Manatt Martin, U.S. Pat. No. 2,893,164;
Williams, U.S. Pat. No. 5,615,429; Woods et al., U.S. Pat. No.
6,012,185; Keshavjee, U.S. Pat. No. 6,540,190 B2; Payne et al.,
U.S. Pat. No. 6,948,688 B1; Peterson, U.S. Design Pat. No. Des.
338,360; Abraham et al., U.S. Design Pat. No. D485,746 S; and Pehta
et al., U.S. Design Pat. No. D498,412 S. These systems are
relatively stable for small lateral forces; however none of these
systems account for large vertical earthquake forces that could
displace the legs from the top of the blocks and most are
considered unattractive.
BRIEF SUMMARY OF THE INVENTION
[0007] The present invention is an easily installed and easily
reversed system for the incremental height adjustment of furniture
having wooden legs that are either not circular in cross-section or
are circular in cross-section but have vertical patterns or designs
that are desired to be aligned. Adjustment in height is
accomplished by joining a 1 inch high wood block to the bottom of a
leg through the use of threaded connections that are designed to
allow alignment of the leg and block after the connection is
tightened. Additional blocks are sequentially added to the first
block and likewise aligned until the desired height is obtained,
and a threaded end cap is added to the bottom of the last block.
The blocks may then be finished by painting, staining, etc., as
desired. The blocks will remain attached to the leg when subjected
to large vertical earthquake forces and will remain properly
aligned.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0008] FIG. 1 illustrates a single extension block in accordance
with an embodiment of the present invention.
[0009] FIG. 2 illustrates a cross-section through the vertical axis
of a leg configured to an adjusted height with extension blocks in
accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0010] FIG. 1 illustrates a single extension block comprised of
three parts; a wooden block 1, a threaded rod connector 2, and a
threaded rod or stud bolt 3.
[0011] The wooden block 1 may be of any tree species, the
characteristics of which may vary greatly and which may affect the
size and shape of the other parts required to achieve the present
invention. The wooden block 1 is generally one inch high with a
length and width determined in conjunction with the size of the leg
4 to which it will attach and it may have patterns or designs upon
its sides.
[0012] The threaded rod connector 2 is made of steel and the
exterior of its horizontal cross-section is any shape except a
circle.
[0013] The threaded rod or stud bolt 3 is made of steel and is
compatible with the threaded rod connector 2 for the size and
spacing of threads.
[0014] The extension block is formed by drilling a pilot hole
through the center of the wood block 1 that is slightly smaller
than the horizontal cross-section of the threaded rod connector 2,
then pressing or driving the threaded rod connector 2 into the hole
and seating it below the surface of the wood block 1. The
non-circular cross-section of the threaded rod connector 2 will
force the threaded rod connector 2 and wooden block 1 to rotate
about their vertical axis in tandem; i.e., one cannot rotate
relative to the other. A length of threaded rod 3 is then screwed
into the threaded rod connector 2 and glued at the proper depth, or
a stud bolt 3 may be screwed into the threaded rod connector 2 with
the unthreaded portion of the stud bolt 3 located to control the
depth of penetration.
[0015] The assembled extension block is then attached to a threaded
rod connector 2 installed in the bottom of a leg either at the
factory or by the end-user. Installation of the threaded rod
connector 2 during the manufacturing process is preferred because
they have more equipment choices and very experienced personnel.
For good results, the threaded rod connector's 2 vertical axis must
be aligned with the leg's 4 vertical axis and the threaded rod
connector 2 glued or restrained in some manner at the proper depth
in the leg 4. If the threaded rod connector 2 is not installed at
the factory, the end-user can achieve satisfactory results using a
hand-held drill and a drilling guide. A simple guide could be a
wooden block supplied by the extension block manufacturer that is
two inches thick and the same width and length as the supplied
extension blocks with a pre-drilled hole along the guide's vertical
axis. The user places the side of the guide with the hole against
the bottom of the leg 4 and aligns the sides of the guide with the
sides of the leg 4, then inserts a properly sized drill bit that
has been marked with tape at three inches and drills a hole one
inch into the leg along its vertical axis. The user places several
drops of glue into the hole and drives the threaded rod connector 2
into the hole with a hammer and sets it below the wood surface
using a hammer and punch or a hammer and screw driver.
[0016] Once the threaded rod or stud bolt 3 of the extension block
is threaded into the threaded rod connector 2 in the leg 4, the
extension block is rotated clockwise until it contacts the wood at
the bottom of the leg 4. At this point the sides of the wooden
block 1 will most likely not align with the sides of the leg 4 so
additional force is applied in the clockwise direction to rotate
the wooden block 1 until the sides align with the leg's 4 sides.
The additional rotation of the wooden block 1 while it is bearing
against the leg 4 will result in the threaded rod connector 2 being
pulled upward toward the leg 4. This is a form of an Archimedes
screw and the distance the threaded rod connector 2 moves is equal
to the number of threads per inch times the number of rotations, or
for twenty threads per inch at one half turn the distance moved is
one fortieth of an inch. The amount of force necessary to rotate
the wooden block 1 into an aligned position depends upon the
surface area of the threaded rod connector 2 against the wooden
block 1, the roughness of the threaded rod connector 2 surfaces,
and the roughness, strength and moisture content of the wood in
contact with the threaded rod connector 2.
[0017] Additional extension blocks may be added to the bottom of
the first extension block and aligned as described above, one at a
time, until the desired height is achieved. A threaded end cap 5 is
added to the bottom of the last extension block to stabilize it.
FIG. 2 illustrates the extension of a leg 4 using two extension
blocks.
[0018] The above procedure is also used with extension blocks
having a circular cross-section with patterns or designs on the
exterior that are desired to be aligned vertically for aesthetic
reasons.
[0019] The above procedure is reversible and the parts are
reusable.
[0020] The final installation may be finished as desired by normal
wood finishing techniques.
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