U.S. patent application number 09/776022 was filed with the patent office on 2002-08-08 for multi-leg telescopic linear actuator.
Invention is credited to Zimmerman, Dean A..
Application Number | 20020104395 09/776022 |
Document ID | / |
Family ID | 25106241 |
Filed Date | 2002-08-08 |
United States Patent
Application |
20020104395 |
Kind Code |
A1 |
Zimmerman, Dean A. |
August 8, 2002 |
MULTI-LEG TELESCOPIC LINEAR ACTUATOR
Abstract
A compact telescopic leg assembly includes a generally
cylindrical drive motor mounted axially within the inner leg and
coupled to a drive collar by a pedestal mount. A drive screw is
threadably coupled to a first drive collar which is attached to the
inner leg to raise and lower as the drive screw is rotated by the
motor. The pedestal mount couples the motor through the first drive
collar to a second drive collar which is coupled to an intermediate
leg telescopically receiving the inner leg. Gears couple the
motor-driven drive screw to a rotatable power nut coupled to the
second drive collar. A fixed drive screw extends from the base
within an outer leg upwardly through the second drive collar and
cooperates with the power nut within the second drive collar to
simultaneously extend and retract the legs as the motor rotates the
motor-driven drive screw.
Inventors: |
Zimmerman, Dean A.;
(Comstock Park, MI) |
Correspondence
Address: |
PRICE HENEVELD COOPER DEWITT & LITTON
695 KENMOOR, S.E.
P O BOX 2567
GRAND RAPIDS
MI
49501
US
|
Family ID: |
25106241 |
Appl. No.: |
09/776022 |
Filed: |
February 2, 2001 |
Current U.S.
Class: |
74/89.35 |
Current CPC
Class: |
Y10T 74/18672 20150115;
F16H 2025/2059 20130101; A47B 9/04 20130101; F16H 2025/2075
20130101; F16H 25/2056 20130101; A47B 2200/0059 20130101 |
Class at
Publication: |
74/89.35 |
International
Class: |
F16H 003/06; F16H
027/02; F16H 029/02; F16H 029/20 |
Claims
The invention claimed is:
1. A telescopic multiple leg assembly comprising: outer,
intermediate and inner telescopically coupled legs; a fixed drive
screw extending from one end of said outer leg; a drive collar
including a rotatable power nut mounted therein and coupled to said
fixed drive screw such that rotation of the power nut moves said
drive collar with respect to said outer leg and with respect to
said fixed drive screw, said drive collar coupled to said
intermediate leg for moving said intermediate leg with movement of
said drive collar; a drive motor coupled to said drive collar by a
plurality of elongated rods spacing said drive motor axially from
said drive collar; a rotatable drive screw coupled to said drive
motor for rotation of said rotatable drive screw, said rotatable
drive screw having an end including a drive gear coupled to said
power nut for rotating said power nut within said drive collar to
extend and retract said intermediate leg with respect to said outer
leg; and an additional drive collar mounted to an end of said inner
leg and including an additional threaded drive nut engaging said
rotatable drive screw to extend and retract said inner leg with
respect to said intermediate leg such that as said rotatable drive
screw is rotated, said inner leg moves with respect to said
intermediate leg and said intermediate leg moves with respect to
said outer leg.
2. The assembly as defined in claim 1 wherein said motor has a
drive shaft and said rotatable drive screw is coupled directly to
said drive shaft.
3. The assembly as defined in claim 1 wherein said legs are
tubes.
4. The assembly as defined in claim 3 wherein said motor is
positioned within said inner leg.
5. The assembly as defined in claim 4 wherein said drive collar and
said additional drive collar are movably positioned within said
outer and within said intermediate legs, respectively.
6. The assembly as defined in claim 5 wherein said legs are
cylindrical.
7. The assembly as defined in claim 6 wherein said power nut in
said drive collar includes a ring gear which meshes with said drive
gear on said rotatable drive screw.
8. A telescopic multiple leg assembly comprising: outer,
intermediate and inner telescopically coupled tubular legs; a fixed
drive screw extending from one end of said outer leg within said
leg; a drive collar including a rotatable power nut mounted therein
and coupled to said fixed drive screw such that rotation of the
power nut moves said drive collar within said outer leg and with
respect to said fixed drive screw, said drive collar coupled to
said intermediate leg for moving said intermediate leg with
movement of said drive collar; a drive motor positioned within said
inner leg and coupled to said drive collar by a plurality of
elongated rods spacing said drive motor axially from said drive
collar; a rotatable drive screw coupled to said drive motor for
rotation of said rotatable drive screw, said rotatable drive screw
having an end including a drive gear coupled to said power nut for
rotating said power nut within said drive collar to extend and
retract said intermediate leg with respect to said outer leg; and
an additional drive collar mounted to an end of said inner leg
within said intermediate leg and including an additional threaded
drive nut engaging said rotatable drive screw to extend and retract
said inner leg with respect to said intermediate leg such that as
said rotatable drive screw is rotated, said inner leg moves with
respect to said intermediate leg and said intermediate leg moves
with respect to said outer leg.
9. The assembly as defined in claim 8 wherein said motor has a
drive shaft and said rotatable drive screw is coupled directly to
said drive shaft.
10. The assembly as defined in claim 8 wherein said rotatable power
nut includes a ring gear engaging said drive gear on said rotatable
drive screw.
11. The assembly as defined in claim 10 wherein three elongated
rods couple said drive motor to said drive collar.
12. The assembly as defined in claim 11 wherein said additional
drive collar includes apertures through which said rods extend such
that said additional drive collar moves axially along said rods as
said rotatable drive screw rotates.
13. The assembly as defined in claim 12 wherein said rods are
spaced at approximately 120.degree. intervals.
14. The assembly as defined in claim 13 wherein said legs are
generally cylindrical.
15. The assembly as defined in claim 14 wherein said additional
drive collar includes an annular shoulder engaging an annular end
of said inner leg.
16. A compact telescopic multiple leg assembly for a table
comprising: outer, intermediate and inner telescopically coupled
legs, wherein one end of said outer leg rests on a support surface
and the end of said inner leg remote from said one end is adapted
to be coupled to the underside of a table surface; a fixed drive
screw extending from one end of said outer leg within said leg; a
drive collar including a rotatable power nut mounted therein and
coupled to said fixed drive screw such that rotation of the power
nut moves said drive collar within said outer leg and with respect
to said fixed drive screw, said drive collar coupled to said
intermediate leg for moving said intermediate leg with movement of
said drive collar; a drive motor positioned within said inner leg
and coupled to said drive collar by a plurality of elongated rods
spacing said drive motor axially from said drive collar; a
rotatable drive screw coupled to said drive motor for rotation of
said rotatable drive screw, said rotatable drive screw having an
end including a drive gear coupled to said power nut for rotating
said power nut within said drive collar to extend and retract said
intermediate leg with respect to said outer leg; and an additional
drive collar mounted to an end of said inner leg within said
intermediate leg and including an additional threaded drive nut
engaging said rotatable drive screw to extend and retract said
inner leg with respect to said intermediate leg such that as said
rotatable drive screw is rotated, said inner leg moves with respect
to said intermediate leg and said intermediate leg moves with
respect to said outer leg.
17. A drive system for a multiple leg assembly comprising: outer,
intermediate and inner telescopically coupled legs; a drive collar
movably positioned within said outer leg and coupled to said
intermediate leg, said drive collar including a power nut rotatably
mounted therein; a drive motor positioned within said inner leg and
coupled to said drive collar by a plurality of elongated rods
axially spacing said drive motor from said drive collar; a fixed
drive screw extending from one end of said outer leg and within
said leg, said power nut engaging said fixed drive screw; a
rotatable drive screw coupled to said drive motor for rotation of
said rotatable drive screw, said rotatable drive screw having an
end including a drive gear coupled to said power nut for rotating
said power nut within said drive collar to extend and retract said
intermediate leg with respect to said outer leg; and an additional
drive collar mounted to an end of said inner leg within said
intermediate leg and including an additional threaded drive nut
engaging said rotatable drive screw to extend and retract said
inner leg with respect to said intermediate leg such that as said
rotatable drive screw is rotated, said inner leg moves with respect
to said intermediate leg and said intermediate leg moves with
respect to said outer leg.
18. The assembly as defined in claim 17 wherein said legs are
tubes.
19. The assembly as defined in claim 18 wherein said rotatable
power nut includes a ring gear engaging said drive gear on said
rotatable drive screw.
20. The assembly as defined in claim 19 wherein three elongated
rods couple said drive motor to said drive collar.
21. The assembly as defined in claim 20 wherein said additional
drive collar includes apertures through which said rods extend such
that said additional drive collar moves axially along said rods as
said rotatable drive screw rotates.
22. The assembly as defined in claim 21 wherein said rods are
spaced at approximately 120.degree. intervals.
23. The assembly as defined in claim 22 wherein said legs are
generally cylindrical.
24. The assembly as defined in claim 23 wherein said additional
drive collar includes an annular shoulder engaging an annular end
of said inner leg.
25. The assembly as defined in claim 17 wherein said motor has a
drive shaft and said rotatable drive screw is coupled directly to
said drive shaft.
26. A drive assembly for use with a telescopic leg section
comprising: a stationary drive screw; a drive collar including a
rotatable power nut mounted therein and coupled to said stationary
drive screw such that rotation of the power nut moves said drive
collar with respect to said stationary drive screw; a drive motor
coupled to said drive collar by a plurality of elongated rods
spacing said drive motor axially from said drive collar; a
rotatable drive screw coupled to said drive motor for rotation of
said rotatable drive screw, said rotatable drive screw having an
end including a drive gear coupled to said power nut for rotating
said power nut within said drive collar to extend and retract said
drive collar; and an additional drive collar including an
additional threaded drive nut engaging said rotatable drive screw
to extend and retract said additional drive collar as said
rotatable drive screw is rotated.
27. The assembly as defined in claim 26 wherein said motor has a
drive shaft and said rotatable drive screw is coupled directly to
said drive shaft.
28. The assembly as defined in claim 27 wherein said rotatable
power nut includes a ring gear engaging said drive gear on said
rotatable drive screw.
29. The assembly as defined in claim 28 wherein three elongated
rods couple said drive motor to said drive collar.
30. The assembly as defined in claim 29 wherein said additional
drive collar includes apertures through which said rods extend such
that said additional drive collar moves axially along said rods as
said rotatable drive screw rotates.
31. The assembly as defined in claim 30 wherein said rods are
spaced at approximately 120.degree. intervals.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a motor-driven, telescopic
leg and particularly to a compact assembly allowing the mounting of
a drive motor within the leg.
[0002] In recent years, power-driven adjustable work surfaces, such
as tables, work benches and the like, have become increasingly
popular in work areas in which it is sometimes desirable to be in a
seated position and at other times desirable to be in a standing
position, such that table height adjustment is desirable.
Utilization of power-driven telescopic legs has facilitated the
adjustment of such work surfaces, and typically a pancake-type or
other motor drive with a right angle connection to a jack drive
screw has been employed. With such a system, the motor is external
to the telescopic table leg and is typically mounted to the
undersurface of the table. A right angle drive couples to a drive
screw, which engages a drive nut, for controlling the telescopic
motion of the table leg. Although such a system works adequately,
the mounting of a motor to the undersurface of the table is
somewhat bulky and unsightly. It is, therefore, desirable to
provide a more aesthetically acceptable construction without the
need for a motor pod mounted to the undersurface of the tables at
each of the leg locations. Attempts have been made to provide a
motor drive within the telescopic leg of a table, however, the
drive motor occupies significant space and cannot easily be
incorporated within the telescopic leg of a table in view of the
space constraints.
[0003] There exists, therefore, a need for a telescopic
motor-driven leg assembly in which the motor can be incorporated
within the leg structure and yet provide sufficient torque for
lifting a significant work surface at a reasonable speed to
accommodate modern conveniently adjustable work surfaces.
SUMMARY OF THE INVENTION
[0004] The system of the present invention provides a motor-driven
telescopic leg assembly providing sufficient excursion to move a
table top or work surface between a lowered position and a raised
position. The telescopic leg assembly includes a generally
cylindrical drive motor mounted within an inner leg and is coupled
in spaced relationship to a drive collar by a pedestal mount. A
drive screw couples the motor to a first drive collar which is
attached to the inner leg to raise and lower as the drive screw,
which is threadably coupled to the first drive collar by a drive
nut, is rotated by the motor. A pedestal mount extends through the
first drive collar and to a second drive collar which is coupled to
an intermediate leg telescopically receiving the inner leg. Gears
couple the motor-driven drive screw to a rotatable power nut
coupled to the second drive collar. A fixed drive screw extends
from the base within an outer leg upwardly in fixed relationship
through the second drive collar and receives the gear driven drive
nut within the intermediate leg to raise and lower as the motor
rotates the motor-driven drive screw.
[0005] By providing a pedestal mounted motor in axial alignment
within the three telescopic legs at one end, the inner leg diameter
can accommodate a motor of sufficient size and power to provide the
desired drive forces for adjusting work surfaces providing both the
excursion and drive speed necessary.
[0006] These and other features, objects and advantages of the
present invention will become apparent upon reading the following
description thereof together with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view, partly in phantom form, of a
telescopic leg assembly embodying the present invention, shown in a
fully extended position;
[0008] FIG. 2 is a perspective view, partly in phantom form, of the
assembly shown in FIG. 1, shown in a fully retracted position;
[0009] FIG. 3 is an exploded perspective view of the motor and
pedestal mounting subassembly, shown in FIGS. 1 and 2;
[0010] FIG. 4 is a exploded perspective view of the motor mount
pedestal and first and second drive collars;
[0011] FIG. 5 is an exploded perspective view of the first drive
collar, shown in FIGS. 1, 2, and 4;
[0012] FIG. 6 is an exploded perspective view of the second drive
collar and the gear drive mechanism coupling the second drive
collar to the motor-driven drive screw;
[0013] FIG. 7 is an enlarged fragmentary vertical cross-sectional
view of the drive collars; and
[0014] FIG. 8 is an exploded perspective view of the gear drive and
power nut for the second drive collar.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0015] Referring initially to FIG. 1, there is shown a telescopic
leg assembly 10 embodying the present invention which is coupled
between a support such as a floor 12 at its base and to a movable
member, such as the undersurface of tabletop 14, using conventional
fasteners (not shown). The telescopic leg assembly 10 includes, in
the preferred embodiment, three generally cylindrical tubes with an
outer or base leg 16, an intermediate leg 18, and an inner leg 20,
each of which are generally cylindrical in cross section and have
their inner surfaces typically coated with a lubricious polymeric
material to allow the telescopic sliding of the legs 20 and 18
within each other and within the outer leg 16. Leg 16 has a 70 mm
outer diameter (OD) and a 66 mm inner diameter (ID). Leg 18 has a
65 mm OD and a 61 mm ID. Leg 20 has a 60 mm OD and a 56 mm ID. The
leg assembly 10 can be extended from a fully collapsed or retracted
position shown in FIG. 2, which in one embodiment was approximately
54 cm, to a fully extended position as shown in FIG. 1, which in
the preferred embodiment was approximately 114 cm, and is driven by
an electric motor 30 mounted coaxially within the inner leg 20 by
the novel mounting and drive system of the present invention which
allows the motor 30 to be accommodated within the cylindrical
volume of the inner leg 20 for all ranges of motion between the
limits seen in FIGS. 1 and 2. Thus, a relatively powerful electric
drive motor 30 can be employed and accommodated by mounting at one
end of the drive mechanism within the relatively confined space of
the inner leg 20 and yet provide sufficient torque to drive the leg
at a speed of, for example, 38 mm per second in one embodiment,
raising a load of 60 k for each leg assembly 10 embodied in a table
assembly. Typically, a table assembly will include at least two
pedestal legs and, in some embodiments, three or four. The unique
mounting assembly and drive mechanism for the motor positioned at
one end within the inner leg of the telescopic leg assembly is now
described in greater detail.
[0016] The basic elements of the drive system, including the motor
30, comprises a pedestal mount which physically couples the motor
in fixed spaced relationship to a second drive collar 50 (FIGS. 1,
2, and 4) by means of three equally spaced mounting rods 22, 24,
and 26, which are mounted to the motor 30 at approximately
120.degree. intervals as described below and which extend through
generally circular clearance apertures 32, 34, and 36,
respectively, (FIG. 4) in a first drive collar 40 such that drive
collar 40 moves with relationship to the mounting rods 22, 24, 26.
Motor 30 is coupled to a mounting plate 38 by means of fastening
screws 39 (FIG. 3). The solid rod pedestals 22, 24, and 26 are
mounted within recessed blind apertures 31 in mounting plate 38
which are spaced at approximately 120.degree. intervals and which
receive one end 21 of each of the rods, which include a threaded
aperture for receiving attaching screws, such as cap screws 33,
mounting the rod ends 21 to mounting plate 38, which subsequently
is mounted to the motor 30. The opposite ends 23 of mounting rods
22, 24, and 26 are fixedly secured within cylindrical apertures 51
of drive collar 50 by means of fastening screws 95 (FIGS. 4 and 7),
which also attach mounting plate 94 to the undersurface of drive
collar 50. For such purpose, the ends 23 of mounting rods 22, 24,
and 26 include threaded apertures for receiving fasteners 95.
[0017] Motor 30 includes a drive shaft 35 which is coupled to a
drive screw 60 (FIGS. 1, 2, and 4) having an externally threaded
surface which inter-engages a drive nut 42 in the first drive
collar 40. Drive nut 42 is internally threaded, as shown
schematically at 41 in FIG. 5 and is fixedly seated within an
aperture 44 in drive collar 40 and held therein by a spring
retainer ring 45. The drive nut 42 is thus fixed within drive
collar 40. As drive screw 60 rotates with respect to drive collar
40, the drive collar moves toward and away from the motor 30 as
seen in FIGS. 1 and 2.
[0018] Drive collar 40 includes a generally annular shoulder 46 on
which the end of the inner leg 20 rests. As the drive collar moves
in a direction to extend the leg 20, leg 20 will be lifted by the
shoulder 46. Flush mounted set screws also extend at 120.degree.
intervals between leg 20 and the cylindrical outer wall of drive
collar 40 into threaded apertures 47 for providing a positive
coupling of the drive collar 40 to the inner telescopic leg 20.
Drive collar 40 also includes an axially extending cylindrical
clearance aperture 48 for allowing a second fixed drive screw 70,
which is mounted to a base plate 72 by means of a fastening screw
74 (FIG. 7) to extend through and into drive collar 40 when in a
fully collapsed position, as seen in FIGS. 2, 4, and 7.
[0019] The end 61 of drive screw 60 is coupled to motor drive shaft
35 by means of a coupling collar 64 (FIG. 4). A roll pin 63 extends
into the drive screw end 61, and a set screw 65, which threadably
extends through collar 64, engages a flat on drive shaft 35. The
opposite end 68 of drive screw 60 is coupled to a thrust bearing 80
(FIG. 6) seated within a cylindrical aperture 52 in lower drive
collar 50 to position a drive gear 66 fixedly mounted to the drive
screw 60 in spaced relationship to end 68 of drive screw 60 to
position the drive gear in meshing relationship with a ring gear 82
fixedly coupled to a power nut 84 within the second drive collar
50, which is internally threaded to engage fixed drive screw 70.
Nut 84 is, therefore, driven by the powered drive screw 60 and is
captively held within the second drive collar 50 to raise and lower
the second drive collar from base 72, as seen in FIGS. 1 and 2, as
power nut 84 is driven through meshed gears 66 and 82. The power
nut 84 is captively held within aperture 54 of drive collar 50 by
means of a thrust washer 56 and thrust bearing 58 held within the
second drive collar 50 by means of a mounting plate 90 (FIG. 4)
(which is secured within threaded apertures of the upper surface of
drive collar 50 by suitable fasteners, such as screws 95). Thus,
power nut 84 is sandwiched between plate 90 and bushing 54 by
having plate 94 hold bushing 54 by screws 95 and rods 22. Screws 92
secure leg 18 to collar 50.
[0020] Drive collar 50, like drive collar 40, engages the
intermediate leg 18 and also may be fixed thereto by flush mounted
set screws 92 extending within holes of the cylindrical sidewall of
leg 18 into threaded apertures in drive collar 50 to provide a
positive locking engagement with the intermediate leg 18. A bottom
plate 94 (FIG. 4) captively holds the opposite end of power nut 84
and an associated bushing 54 within the second drive collar 50.
Plate 94 is mounted to the threaded apertures 23 in rods 22, 24, 26
and to drive collar 50 by means of threaded fasteners 95. Plate 94
has a diameter that is slightly greater than that of drive collar
50 and the bottom annular surface of leg 18 rests on the annular
extension, as best seen in FIG. 7.
[0021] The ring gear 82 is lockably fitted to an annular shoulder
85 on power nut 84 by means of a pair of roll pins 86 extending
axially within the shoulder 85 and within suitable apertures formed
in the ring gear 82 and power nut such that force is transferred
from drive gear 66, also lockably mounted to drive screw 60 with a
roll pin, to the power nut 84, which is rotatably mounted within
the drive collar 50 by means of thrust washer 56, thrust bearing
58, and a bushing 54 on the opposite side of shoulder 85. Drive
screw 60 is secured within aperture 52 of drive collar 50 utilizing
the thrust bearing 80 with the end 68 of the drive screw 60 being
supported by a bushing 53, as seen in FIGS. 4, 6, and 7. A snap
ring 55 (FIGS. 4 and 5) fits within an annular groove in the end 68
to captively hold end 68 within the second drive collar 50.
[0022] Drive screw 60 rotates with respect to both drive collars 40
and 50 and causes drive collar 40 to raise and lower within the
intermediate leg 18, raising and lowering inner leg 20. Gear 66
near the end of drive screw 60 meshes with the ring gear 82 on
power nut 84 to cause the second drive collar 50 to raise and lower
on the fixed drive screw 70 which, in turn, raises and lowers the
intermediate leg 18 and the motor 30 through the mounting pedestal,
including rods 22, 24, and 26, secured to the second drive collar
50.
[0023] Thus, as the drive screw 60 is rotated by motor 30, which,
in a preferred embodiment, was a commercially available Pittman
Model GM9236E347 motor, drive collar 40 raises and lowers and, in
turn, drives power nut 84 captively held within drive collar 50 to
also raise and lower on fixed drive screw 70 mounted to the base
plate 72, in turn, resting on a support, such as floor 12. The
rotation of drive screw 60, therefore, causes both drive collars to
move axially within the telescopic intermediate leg 18 and outer
leg 16 and their coupling to legs 18 and 20, causing the legs to
telescopically extend and retract. By providing the motor 30 at one
end of the assembly and generally axially aligned with the
innermost leg 20, the motor size can be sufficient to substantially
occupy the cylindrical volume of leg 20 and thereby be of
sufficient size to provide a torque and drive speed necessary for
the convenient movement of an adjustable work surface to which the
telescopic leg assembly 10 is mounted. Electrical power is supplied
to motor 30 through a coiled conductor (not shown) which
straightens when the assembly 10 is in an extended position, as
seen in FIG. 1, and coils when in a position as seen in FIG. 2.
Although the invention finds application to the mounting of a table
surface for adjustment, it could likewise be employed in any
environment in which it is desired to move one member with respect
to another utilizing a streamlined telescopic tube assembly with an
internally mounted motor drive.
[0024] The outer diameter of the cylindrical drive collars is
selected to allow them to move easily within the inner diameters of
the inner leg 20 and the intermediate leg 18, respectively.
Although in the preferred embodiment of the invention the legs are
shown as being cylindrical, any tubular leg, such as square or
rectangular, can be employed and the drive collar shapes selected
to accommodate such different configured legs. These and other
modifications to the preferred embodiment will become apparent to
those skilled in the art and such modifications to the preferred
embodiment of the invention as described herein can be made without
departing from the spirit or scope of the invention as defined by
the appended claims.
* * * * *