U.S. patent application number 14/947589 was filed with the patent office on 2016-05-26 for drywall lift.
The applicant listed for this patent is Patrick M. Glance. Invention is credited to Patrick M. Glance.
Application Number | 20160145879 14/947589 |
Document ID | / |
Family ID | 56009654 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160145879 |
Kind Code |
A1 |
Glance; Patrick M. |
May 26, 2016 |
Drywall Lift
Abstract
A four-bar linkage based lift is operable by a single person.
The lift is used to raise a drywall panel to a ceiling, allowing
the drywall panel to be mounted to the ceiling rafters. The lift
includes a base link structure, an upright link structure, a
working link structure, and a supporting link structure. The
upright link structure is adjacently connected to the base link
structure, while a first axle creates a hinged connection between
the working link structure and the upright link structure. The
working link structure can thus be rotated upwards in order to lift
a drywall panel, the drywall panel being supported by a drywall
retaining shelf of the working link structure. The supporting link
structure, formed of an independent first stay and second stay, can
be rotated to an upright position to support the raised working
link structure.
Inventors: |
Glance; Patrick M.;
(Pinckney, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Glance; Patrick M. |
Pinckney |
MI |
US |
|
|
Family ID: |
56009654 |
Appl. No.: |
14/947589 |
Filed: |
November 20, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62083778 |
Nov 24, 2014 |
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Current U.S.
Class: |
414/11 |
Current CPC
Class: |
E04F 21/1822
20130101 |
International
Class: |
E04F 21/18 20060101
E04F021/18 |
Claims
1. A drywall lift comprises: a base link structure; an upright link
structure; a working link structure; a supporting link structure;
the working link structure comprises a drywall retaining shelf; the
supporting link structure comprises a first stay and a second stay;
the upright link structure being adjacently and perpendicularly
connected to the base link structure; the working link structure
being hingedly connected to the upright link structure through a
first axle; the working link structure being oppositely positioned
from the base line structure across the upright link structure; the
supporting link structure being hingedly connected to the working
link structure through a second axle; and the supporting link
structure being oppositely positioned from the upright link
structure across the working link structure.
2. The drywall lift as claimed in claim 1 comprises: a first
buttress and a second buttress; the first buttress and the second
buttress being oppositely positioned of each other across the base
link structure and the upright link structure; the first buttress
being angularly connected between the base link structure and the
upright link structure; the second buttress being angularly
connected between the base link structure and the upright link
structure; the first stay being hingedly connected with the working
link structure; the first stay being adjacently positioned with the
first buttress; the second stay being hingedly connected with the
working link structure; and the second stay being adjacently
positioned with the second buttress.
3. The drywall lift as claimed in claim 1 comprises: the drywall
retaining shelf being adjacently positioned with a top surface of
the working link structure; and the drywall retaining shelf being
centrally connected with the working link structure.
4. The drywall lift as claimed in claim 1 comprises: the upright
link structure, the first stay, and the second stay each comprise a
fixed member, an extension member, and a locking mechanism; the
extension member being slidably engaged with the fixed member; the
locking mechanism being mounted to the fixed member; and the
locking mechanism being selectively engaged with the extension
member.
5. The drywall lift as claimed in claim 1 comprises: the base link
structure comprises a first leg and a second leg; the upright link
structure comprises a first pillar and a second pillar; the working
link structure comprises a first arm and a second arm; the first
pillar being connected perpendicular to the first leg; the second
pillar being connected perpendicular to the second leg; and the
drywall retaining shelf being connected across the first arm and
the second arm.
6. The drywall lift as claimed in claim 5 comprises: the first axle
traversing through the first pillar, the second pillar, the first
arm, and the second arm; the first axle being positioned opposite
the base link structure along the first pillar and the second
pillar; and the first axle being positioned opposite the supporting
link structure along the first arm and the second arm.
7. The drywall lift as claimed in claim 5 comprises: the second
axle traversing through the first arm, the second arm, the first
stay, and the second stay; the second axle being positioned
opposite the upright link structure along the first arm and the
second arm; and the second axle being positioned adjacent to the
working link structure along the first stay and the second
stay.
8. The drywall lift as claimed in claim 5 comprises: the working
link structure further comprises an at least one cross brace; and
the at least one cross brace being perpendicularly connected with
the first arm and the second arm.
9. A drywall lift comprises: a base link structure; an upright link
structure; a working link structure; a supporting link structure;
the working link structure comprises a drywall retaining shelf; the
supporting link structure comprises a first stay and a second stay;
a first buttress and a second buttress; the upright link structure,
the first stay, and the second stay each comprise a fixed member,
an extension member, and a locking mechanism; the base link
structure comprises a first leg and a second leg; the upright link
structure comprises a first pillar and a second pillar; the working
link structure comprises a first arm and a second arm; the upright
link structure being adjacently and perpendicularly connected to
the base link structure; the working link structure being hingedly
connected to the upright link structure through a first axle; the
working link structure being oppositely positioned from the base
line structure across the upright link structure; the supporting
link structure being hingedly connected to the working link
structure through a second axle; the supporting link structure
being oppositely positioned from the upright link structure across
the working link structure; the first buttress and the second
buttress being oppositely positioned of each other across the base
link structure and the upright link structure; the extension member
being slidably engaged with the fixed member; the locking mechanism
being mounted to the fixed member; and the locking mechanism being
selectively engaged with the extension member.
10. The drywall lift as claimed in claim 9 comprises: the first
buttress being angularly connected between the base link structure
and the upright link structure; the second buttress being angularly
connected between the base link structure and the upright link
structure; the first stay being hingedly connected with the working
link structure; the first stay being adjacently positioned with the
first buttress; the second stay being hingedly connected with the
working link structure; and the second stay being adjacently
positioned with the second buttress.
11. The drywall lift as claimed in claim 9 comprises: the drywall
retaining shelf being adjacently positioned with a top surface of
the working link structure; and the drywall retaining shelf being
centrally connected with the working link structure.
12. The drywall lift as claimed in claim 9 comprises: the first
pillar being connected perpendicular to the first leg; the second
pillar being connected perpendicular to the second leg; and the
drywall retaining shelf being connected across the first arm and
the second arm.
13. The drywall lift as claimed in claim 9 comprises: the first
axle traversing through the first pillar, the second pillar, the
first arm, and the second arm; the first axle being positioned
opposite the base link structure along the first pillar and the
second pillar; and the first axle being positioned opposite the
supporting link structure along the first arm and the second
arm.
14. The drywall lift as claimed in claim 9 comprises: the second
axle traversing through the first arm, the second arm, the first
stay, and the second stay; the second axle being positioned
opposite the upright link structure along the first arm and the
second arm; and the second axle being positioned adjacent to the
working link structure along the first stay and the second
stay.
15. The drywall lift as claimed in claim 9 comprises: the working
link structure further comprises an at least one cross brace; and
the at least one cross brace being perpendicularly connected with
the first arm and the second arm.
Description
[0001] The current application claims a priority to the U.S.
Provisional Patent application Ser. No. 62/083,778 filed on Nov.
24, 2014.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a drywall lift
which is based upon a four-bar linkage and is operable by a single
person.
BACKGROUND OF THE INVENTION
[0003] The increased use of drywall in housing means the ability to
easily and efficiently install drywall is essential to home
contractors. The need is even greater for ceiling installations of
drywall, as it is difficult for a single person to install drywall
to ceilings. There is a need to improve the existing methods and
tools for installing drywall to ceilings.
[0004] One current method of installing drywall sheet to the
ceiling employs the use of two men and two cripples. A cripple is a
T-shaped brace constructed commonly of two 2''.times.4'' boards;
usually the boards are about 2 & 8 feet long respectively. The
two men carry the drywall sheet, holding it by its edges. Then the
two men rotate the sheet up over their heads. First one man uses
one hand to grab a cripple and place the cripple under the sheet.
Then the second man does the same, and then the sheet is lifted to
the ceiling. The cripples are wedged between the floor and ceiling
to hold the sheet in place. Next drywall screws are used to attach
the sheet to the ceiling rafters. This method works, but is not
without its drawbacks. For one, a light-weight panel of drywall
(4'.times.8'.times.1/2'' thick) weighs 40 pounds. This is a
cumbersome weight even for a two man team, let alone an individual
worker: it is nearly impossible for a single person to install a
panel of drywall to a ceiling without help.
[0005] To assist individual workers with drywall installation,
there are a number of drywall lifts available. An example of a
common drywall lift is one that works on the same principle of a
single telescoping tube center assemble. The tube is mounted to a
tripod base. A rack, which holds the drywall sheet, is connected to
the top of the tube assembly by a hinge. A hand-operated crank,
connected to a cable, pulley, and hoist, allows the tube to be
moved up and down. This is similar to a boat hoist. These devices
are desirable for a number of reasons: they are operable by a
single person, work well, and have been adopted by numerous
commercial contractors. However, there remains room for
improvement. They are somewhat complex, expensive, heavy, and
require a large amount of effort is required to rise the drywall
ceiling. Furthermore, they are slow; even though they only require
a single operator, it takes a lot of turns on the wheel to raise a
drywall sheet to the ceiling which slows down the installation
process. The present invention seeks to address the shortcoming of
current drywall installation methods by providing an apparatus
which is easily operated by a single person. In addition to being
able to be individually operated, the present invention functions
well, and is used by commercial contractors, and some professional
installers. However, the exiting lifts are somewhat complex,
expensive, heavy, and slow in lifting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a perspective view of the present invention in a
lifted position, wherein the working link structure is
perpendicular to the upright link structure.
[0007] FIG. 2 is a side view showing the present invention in the
lifted position.
[0008] FIG. 3 is a perspective view of the present invention in a
folded position.
[0009] FIG. 4 is a side view showing the present invention in the
folded position.
DETAIL DESCRIPTIONS OF THE INVENTION
[0010] All illustrations of the drawings are for the purpose of
describing selected versions of the present invention and are not
intended to limit the scope of the present invention.
[0011] The present invention is a drywall lift that is operable by
a single person. The present invention is designed for quick and
easy assembly and disassembly with industry standard fasteners and
tools. Additionally, the present invention can be easily handled,
assembled, disassembled, and moved by a single non-professional
person. The present invention is also projected to be 1/3 of weight
and cost of any other existing apparatus that uses to lift
drywalls. These said advantages allow the present invention to be
an efficient apparatus for home improvement projects that are
related to drywall lifting and fills the need for a do-it-self
drywall lifting. The present invention is implemented as a
mechanical linkage, specifically a modified four-bar linkage, and
as such comprises a base link structure 1, an upright link
structure 2, a working link structure 3, and a supporting link
structure 4. The base link structure 1 and the upright link
structure 2 act as fixed links in the present invention, supporting
hinged movement of both the working link structure 3 and the
supporting link structure 4. These combine into a linkage system
with two pivots and one sliding connection. A first pivot is fixed
to the upright link structure 2, while a second pivot moves in an
arc relative to the first pivot. A sliding connection is between a
floor and the bottom of the supporting link structure 4, which
drags across the floor during operation of the present invention.
These core components of the present invention are subsequently
elaborated upon. Illustrations of the present invention are
provided via FIG. 1-FIG. 4.
[0012] The base link structure 1 lies flat against a planar
surface, e.g. a floor. The upright link structure 2 is connected
atop the base link structure 1; these two structures serve as a
fixed frame of the present invention. The upright link structure 2,
being vertical, is oriented to be perpendicular to the base link
structure 1. The working link structure 3 comprises a drywall
retaining shelf 31, which allows a drywall panel to independently
supported and manipulated (e.g. raised towards a ceiling for
connection via ceiling rafters) by the present invention. The
working link structure 3 is hingedly connected to the upright link
structure 2 through a first axle 5. As a result, the working link
structure 3 can be rotated about a fixed end, i.e. the end that is
hinged to the upright link structure 2 by said first axle 5.
Similarly, the supporting link structure 4 is hingedly connected to
the working link structure 3 through a second axle 6. This allows
the supporting link structure 4 to be rotated with respect to the
working link structure 3. This is important as the supporting link
structure 4 can be used to support and secure the working link
structure 3 at a non-equilibrium angle. In reference to FIG. 3 and
FIG. 4, when a drywall panel is loaded to the working link
structure 3, the present invention is in the folded position as the
supporting link structure 4 can be either forward or rearward
facing. When the working link structure 3 is used to raise a
drywall panel to a ceiling. It is noted that the supporting link
structure 4 can support the working link structure 3 at multiple
angles; for example, the supporting link structure 4 can be
positioned at a 45 degree angle relative to the working link
structure 3 and a floor, rather than a 90 degree angle (which would
hold the working link structure 3 parallel to a ceiling). As the
supporting link structure 4 drags along the floor during rotation
of the working link structure 3, it creates leverage and reduces
the amount of effort required to be input by a user. The basic
operation of the present invention is shown in FIG. 1 and FIG. 3,
which illustrate how the components of the present invention relate
with respect to one another.
[0013] In order to further stabilize the structure of the present
invention, a first buttress 7 and a second buttress 8 can be
installed as part of the present invention. The first buttress 7
and second buttress 8 serve as braces between the base link
structure 1 and the upright link structure 2, helping to provide
improved stabilization for the present invention. The first
buttress 7 and the second buttress 8 are positioned opposite each
other across the base link structure 1 and the upright link
structure 2. Effectively, the two buttresses are respectively
positioned at the left side and the right side of the present
invention. Each buttress is positioned at an angle relative to the
base link structure 1 and the upright link structure 2; the first
buttress 7 and second buttress 8 are both angularly connected
between the base link structure 1 and the upright link structure 2,
albeit at opposite sides. In short, from a side profile view, the
buttresses form a triangular shape in combination with the base
link structure 1 and the upright link structure 2. The buttresses
can be seen in FIG. 1-FIG. 4.
[0014] The first stay 41 and the second stay 42, being used to
support the working link structure 3, are each hingedly connected
with the link structure by means of the second axle 6. Resultantly,
the first stay 41 and the second stay 42 can be rotated relative to
the working link structure 3. As the first stay 41 and the second
stay 42 are meant to support the load of the working link structure
3, they are positioned at opposite sides of the present invention.
Resultantly, the first stay 41 is positioned adjacent with the
first buttress 7 while the second stay 42 is positioned adjacent
with the second buttress 8. Each stay effectively remains coplanar
with its corresponding buttress; this holds true when resting on a
floor at an angle (i.e. when a drywall panel is being loaded onto
the drywall retaining shelf 31 and when angled to an upright
position (i.e. when a drywall panel is being fastened to a
ceiling). It is noted that the first stay 41 and the second stay 42
can be rotated about the second axle 6 independently from each
other; this improves safety of the present invention. Even if one
of the stays is knocked away or otherwise fails, the other stay
remains in place and support the drywall panel and working link
structure 3 from falling, resulting in improved workplace
safety.
[0015] The drywall retaining shelf 31, which receives a drywall
panel and secures said drywall panel during rotation towards a
ceiling. Thus, the drywall retaining shelf 31 is adjacently
positioned with a top surface 32 of the working link structure 3.
Furthermore, the drywall retaining shelf 31 is centrally connected
to the working link structure 3; this central positioning means
that a larger portion of the working link structure 3 will be
available to bear the weight of the panel of drywall.
[0016] As the present invention is provided for the installation of
drywall, and because ceiling heights vary, it is desirable to
provide a means of height-adjustment for the present invention. In
support of this, the upright link structure 2, the first stay 41,
and the second stay 42 each comprise a fixed member 91, an
extension member 92, and a locking mechanism 93. The extension
member 92 is slidably engaged with the fixed member 91, effectively
allowing the extension member 92 to be raised or lowered in
relation to the fixed member 91. This allows an operator of the
present invention to adjust the extension member 92 to a desired
height. The locking mechanism 93 is mounted to the fixed member 91
and selectively engaged with the extension member 92; engagement of
the locking mechanism 93 and the extension member 92 prevents
movement of the extension member 92. Disengaging the locking
mechanism 93 from the extension member 92 allows movement of the
extension member 92. The locking mechanism 93 can be reengaged with
the extension member 92 once the extension member 92 has been set
to the desired height.
[0017] A variety of components can be implemented as part of the
locking mechanism 93. In the illustrated embodiment, the locking
mechanism 93 is preferably a spring-loaded latch. The spring-loaded
latch is engaged with the extension member 92 through a plurality
of latch receptacles, the plurality of latch receptacles being
positioned along the extension member 92. A locking shaft of the
spring-loaded latch is pressed against the extension member 92;
when the locking shaft is aligned with one of the plurality of
latch receptacles, the locking shaft traverses into the latch
receptacle. Thus, when the locking shaft is engaged with an
arbitrary latch receptacle from the plurality of latch receptacles,
movement of the extension member 92 relative to the fixed member 91
is prevented. These are shown in FIG. 1 and FIG. 3.
[0018] In other embodiments, as mentioned, different
implementations of the locking mechanism 93 can be utilized. For
example, in one embodiment the locking mechanism 93 is a clamp; by
engaging the clamp pressure is applied to fixed member 91 and the
extension member 92. The resulting frictional forces prevent
movement of the extension member 92. In another example, the
locking mechanism 93 is a screw lock. The screw lock, similar to
the clutch lock, applies pressure to the extension member 92 and
the fixed member 91 In order to prevent movement. Unscrewing the
screw lock releases pressure and allows movement of the extension
member 92 to a desired height. In another example, the locking
mechanism 93 is a twist-lock similar to a painter's extension pole
so that the extensions member 92 is able to move into a desired
height in relation to the fixed member 91. This, along with the
previous examples, is one of a few possible implementations for the
locking mechanism 93 and doesn't not preclude the use of
alternative implementations. Components related to the
height-adjustable nature are shown through FIG. 1-FIG. 4 providing
an example of a height adjustment made through the present
invention.
[0019] Just as different implementations are possible for the
locking mechanism 93, variations in engagement between the fixed
member 91 and the extension member 92 are possible. In the
illustrated embodiment the extension member 92 is shown as being
adjacently engaged with the fixed member 91. That is, the fixed
member 91 serves as a track for the extension member 92.
Resultantly, the extension member 92 can slide along the track of
the fixed member 91 in order to adjust the height of the present
invention. In another embodiment, the extension member 92 traverses
into the fixed member 91, resulting in a telescoping connection
between the extension member 92 and the fixed member 91. The use of
different sliding engagements opens up further possibilities for
locking mechanisms 93, such as a twist lock for the telescoping
engagement. These two examples shown potential means by which the
extension member 92 may be slidably engaged with the fixed member
91; other methods remain possible within the scope of the present
invention.
[0020] The present invention, as thus far described, serves as a
mobile apparatus which allows for a drywall panel to be raised to
an elevated height by a single person. In a default position, the
working link structure 3 rests against the first buttress 7 and the
second buttress 8. The supporting link structure 4, i.e. the first
stay 41 and the second stay 42, are rotated such that they are
parallel with the working link structure 3. This provides better
access to the working link structure 3 for a user of the present
invention. In the described position, the present invention is
similar to an easel, allowing a drywall panel to easily be loaded
onto the working link structure 3 and drywall retaining shelf 31.
Once the drywall panel has been loaded, the working link structure
3 can be rotated away from the upright link structure 2 and towards
a ceiling as the bottom of supporting link structure 4 slides
across the floor and pushes the working link structure 3 and the
drywall up to the ceiling. Once the drywall panel has been raised
to the ceiling, the supporting link structure 4 is perpendicularly
positioned with the floor into an upright position. The supporting
link structure's 4 first stay 41 and second stay 42 can be
independently, rotated, allowing a user to hold the working link
structure 3 up with one hand while rotating the first stay 41 with
their other hand. After rotating the first stay 41 to an upright
position, a user can then rotate the second stay 42 to an upright
position to further stabilize the present invention; with both
stays rotated to an upright position, the upright link structure 2,
first stay 41, and second stay 42 provide multiple load-bearing
sections that are able to hold the working link structure 3 and
drywall panel in a raised position. This effectively converts the
present invention from a "floor-easel" configuration, i.e. prior to
lifting of the drywall panel, to a "support-table" configuration,
i.e. when the drywall panel is raised to the ceiling.
[0021] With the drywall panel being supported by a present
invention, a user has both hands free. The panel can thus be
mounted to the ceiling by a single person. This is an improvement
over other tools, such as the T-shaped brace known as a "cripple",
which require two persons for drywall installation. Thanks to the
height-adjustable nature of the present invention, by means of the
first extension member 92 and second extension member 92, the
present invention can be adapted for use with ceilings of different
height. By moving the extension member 92 of the first stay 41,
second stay 42, and upright link structure 2, the total height of
the present invention can be increased or decreased. This increases
flexibility of the present invention, as it is not limited to
ceilings of a specific height.
[0022] In the illustrated embodiment, the base link structure 1,
the upright link structure 2, and the working link structure 3 each
comprise a number of frame pieces. More specifically, the base link
structure 1 comprises a first leg 11 and a second leg 12. The
upright link structure 2 comprises a first pillar 21 and a second
pillar 22. The working link, comprises a first arm 33 and a second
arm 34. These components effectively serve as a left side and a
right side of the present invention, somewhat similar to the first
buttress 7 and the second buttress 8. On one side, the first pillar
21 is connected perpendicular to the first leg 11. On the other
side, the second pillar 22 is connected perpendicular to the second
leg 12. The drywall retaining shelf 31, which helps secure and bear
the load of the panel of drywall, is connected across the first arm
33 and the second arm 34.
[0023] The first arm 33 and the second arm 34 are rotatable with
respect to the corresponding first pillar 21 and second pillar 22.
This coupling is enabled by the first axle 5, which traverses
through the first pillar 21, the second pillar 22, the first arm
33, and the second arm 34. The first axle 5 is positioned opposite
the base structure along the first pillar 21 and the second pillar
22, allowing the working link structure 3 to be rotated to the same
height as the upright link structure 2. The first axle 5 is also
positioned opposite the supporting link structure 4 along the first
arm 33 and the second arm 34. This positioning maximizes torque; by
using the full length of the working link structure 3 as a lever
arm, a person is more easily able to lift the working link
structure 3.
[0024] While the base link structure 1 can be repositioned through
simple sliding (except when a drywall panel is being raise; the
weight of the drywall panel effectively anchors the base link
structure 1 in place), in some embodiments it is desirable to
facilitate easier repositioning of the present invention. In such
embodiments, lockable wheels, casters, and vertically adjustable
feet could be connected to the base link structure 1.
[0025] The second axle 6, which allows for rotation of the
supporting link structure 4 relative to the working link structure
3, traverses through the first arm 33, the second arm 34, the first
stay 41, and the second stay 42. The second axle 6 is positioned
opposite the upright link structure 2 along the first arm 33 and
the second arm 34; this positioning helps better split the load of
the working link structure 3 between the supporting link structure
4 and the upright link structure 2. The second axle 6 is further
described as being positioned adjacent to the working link
structure 3 along the first stay 41 and the second stay 42; by
being positioned at an end of the supporting link structure 4, the
second axle 6 allows the full height of the supporting link
structure 4 to be used.
[0026] In order to better help bear the load of a panel of drywall,
the working link structure 3 comprises an at least one cross brace
35. This at least one cross brace 35 is perpendicularly connected
with the first arm 33 and the second arm 34. Resultantly, the
structural integrity of the working link structure 3 is improved.
Potentially, more cross brace 35s could be provided to further
increase integrity of the working link structure 3. Furthermore, to
help prevent over-rotation of the first stay 41 and the second stay
42, a stop may be connected adjacent to the end of each arm; the
stop would prevent the stays from rotating beyond 90 degrees
towards the base link structure 1 and upright link structure 2,
which aids the operator knowing when both sides of the drywall
shelf is in full up 90 degree position.
[0027] The components of the base link structure 1, the upright
link structure 2, and the working link structure 3, as formerly
described, are just one example of a possible implementation for
the present invention. As the core concept of the present invention
is the use of a four-bar linkage system (via the base link
structure 1, upright link structure 2, working link structure 3,
and supporting link structure 4), other components can be utilized
as part of the link structures without deviating from the scope of
the present invention. For example, the base link structure 1 and
the upright link structure 2 could be implemented as planar bodies
(e.g. a wooden panel) rather than as legs and pillars.
[0028] Specific materials and dimensions of the present invention
are not restricted; the present invention can easily be fabricated
from available materials, such as recycled decking boards. Higher
end implantations could be constructed from aluminum or other
metals. Likewise, the types of fasteners used are variable; in the
illustrated embodiment compression nuts and sleeves are used to
install the first axle 5 and second axle. However, in a simpler
embodiment, simple screws can be used for connection of the axles.
The effort needed to raise the working link structure 3 is also
variable. For example, during prototype testing, it was found that
lifting effort ranged from 12 to 22 pounds, with initial required
effort being low and increasing as the working link structure 3 is
raised to the ceiling. The amount of effort required can vary based
on the material and dimensions of the present invention, as these
can affect weight of the working link structure 3.
[0029] While the present invention has been described as a drywall
lift, it can be used to raise a variety of building materials. For
example, plywood, sheetrock, beams, trims, lighting, heat ducts,
fans, and further items can be lifted through rotation of the
working link structure 3.
[0030] Although the invention has been explained in relation to its
preferred embodiment, it is to be understood that many other
possible modifications and variations can be made without departing
from the spirit and scope of the invention as hereinafter
claimed.
* * * * *