U.S. patent number 3,775,929 [Application Number 05/152,298] was granted by the patent office on 1973-12-04 for method for installing ceilings.
This patent grant is currently assigned to Laser Alignment, Inc.. Invention is credited to Edward G. Nielsen, Roger J. Roodvoets.
United States Patent |
3,775,929 |
Roodvoets , et al. |
December 4, 1973 |
METHOD FOR INSTALLING CEILINGS
Abstract
A device which emits a rotating beam of collimated light,
preferably a laser source assembly, is mounted at a level which has
a predetermined relationship to the level desired for a suspended
ceiling. A target is placed on a ceiling panel supporting member
and the member is elevated until the target is intercepted by the
light beam at a predetermined line on the target. At this point,
the ceiling supporting member is fixed in place. When it is
desirable to bend the supporting wires before the ceiling
supporting members are installed, the target may be moved along
adjacent the wire and the wire bent at a given distance from the
point where the light beam intercepts the target.
Inventors: |
Roodvoets; Roger J. (Grand
Rapids, MI), Nielsen; Edward G. (Wyoming, MI) |
Assignee: |
Laser Alignment, Inc. (Grand
Rapids, MI)
|
Family
ID: |
22542324 |
Appl.
No.: |
05/152,298 |
Filed: |
June 11, 1971 |
Current U.S.
Class: |
52/747.1;
33/286 |
Current CPC
Class: |
E04F
21/1838 (20130101); E04F 21/1877 (20130101) |
Current International
Class: |
E04F
21/18 (20060101); E04g 021/00 (); E04g
021/10 () |
Field of
Search: |
;33/286,295,293
;52/747,364,365,144 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Bennett H. Brough, A Treatise on Mine Surveying, Griffin & Co.,
London: 1903, 10th Rev. Ed., Sci. Lib. Call No. TN 273. B87 pages
110-115.
|
Primary Examiner: Abbott; Frank L.
Assistant Examiner: Ridgill, Jr.; James L.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A method for installing a suspended ceiling on a predetermined
plane, said ceiling having a supporting gridwork affixed by
fastening means to an overhead supporting structure, comprising the
steps of:
a. temporarily positioning the supporting gridwork below said
supporting structure on said fastening means;
b. temporarily coupling a target member to said gridwork, said
target member having a reference means located a predetermined
distance below said gridwork;
c. projecting a collimated beam of light parallel to said plane and
rotating said beam about an axis normal to said plane to generate a
plane of light parallel to and a predetermined distance below said
predetermined plane;
d. positioning the gridwork to a position wherein the reference
means of said target, while secured on said gridwork, is in
alignment with said plane of light; and
e. permanently securing said fastening means to said gridwork while
said gridwork is held in said position.
2. The method of claim 1 and further including providing said
target member with a translucent screen having an opaque reference
line thereon and projecting said beam of light through said
target.
3. In the method of claim 1 and further including providing said
target member with a screen having a reflector and a reference line
thereon and projecting said beam of light on said screen.
4. The method of claim 1 wherein said supporting gridwork has main
runners and cross members and further comprising the steps of:
a. fixing a first row of main runners in alignment with one another
in a straight line;
b. fixing cross members of a predetermined length to said first row
and to an adjacent runner to form a second aligned row; and
c. leveling said adjacent row using said plane of light.
5. The method of claim 8 and further including the steps of:
a. aligning said first row of runners by projecting a beam of light
parallel to the line desired for said row of runners; and
b. fixing said runners in predetermined relationship to said beam
of light.
6. In the installation of a suspended ceiling on a predetermined
plane over an area having a defined outer perimeter and overhead
supporting structure, said suspended ceiling having a supporting
gridwork affixed to a plurality of perimeter supports fixed and
aligned along said perimeter, the improvement in installing said
supports comprising the steps of:
a. projecting a narrow collimated beam of light parallel to said
plane and sweeping said beam about an axis normal to said plane to
generate a plane of light parallel to said predetermined plane;
b. temporarily securing target member means successively to each of
said perimeter supports said target member means having a reference
means located a predetermined distance below said supports;
c. successively moving each of said perimeter supports and said
target means while secured on said supports to a position wherein
said reference means is in alignment with said plane of light;
and
d. fixing each of said perimeter supports to said perimeter in said
position at which said reference means of said target means is in
alignment with said plane of light.
7. A method for installing a suspended ceiling as defined in claim
10 and further including the steps of:
e. positioning said supporting gridwork on said perimeter
supports;
f. temporarily fastening said supporting gridwork below said
supporting structure;
g. securing said target member means to said grid-work with said
reference means located said predetermined distance below said
gridwork;
h. moving said gridwork and said target means while secured on said
gridwork to a position wherein said reference means is in alignment
with said plane of light; and
i. permanently securing said supporting gridwork below said
supporting structure at said position where said reference means is
in alignment with said plane of light.
8. In the installation of a suspended ceiling on a predetermined
plane over an area, said ceiling having a supporting gridwork
affixed to an elongated fastening means extending downwardly from
and secured to an overhead supporting structure, the improvement in
establishing an affixing means at a position on said fastening
means at which said gridwork is affixed to said fastening means
comprising the steps of:
a. projecting a narrow collimated beam of light parallel to said
plane and sweeping said beam about an axis normal to said plane to
generate a plane of light parallel to and a predetermined distance
spaced from said predetermined plane;
b. providing an intercepter means along said fastening means for
intercepting said plane of light; and
c. establishing said affixing means at a predetermined position on
said fastening means by observing where said plane of light
intercepts said interception means along said fastening means.
9. The method of claim 8 in which said fastening means is a
wire-like member attached at one end to said supporting framework
and said target member is provided with a slotted elongated
tab-like extension along one side thereof wherein in step (b) said
intercepter means is a target and in step (c) said target member is
moved along said fastening means by positioning said extension in
embracing relation with said wire-like member and wherein said
affixing means is formed at said predetermined position by bending
the other end of said wire-like member.
10. The method of claim 8 in which said fastening means is a
wire-like member attached at one end to said supporting frame-work
and the affixing means is formed at said predetermined position by
bending the other end of said wire-like member.
11. The method of claim 8 in which said fastening means is a
wire-like member attached at one end to said supporting member and
said affixing means is a clip member slidably secured to said
wire-like means and wherein in step (b) said intercepter means is a
target member provided on said wire-like member by securing said
target member to said clip and in step (c) said target is moved
along said fastening means by moving said clip along said fastening
means whereby said clip member is established at a predetermined
position on said wire-like member by observing at which position of
said clip member said reference means of said target member is in
alignment with said plane of light.
Description
BACKGROUND OF THE INVENTION
Ceilings, particularly those comprising a plurality of individual
panels supported in a gridwork system suspended from the overhead
joists have become extremely popular in recent years for
installation in new buildings. As a practical matter, ceilings of
this type are relatively easy to install and low in cost. The
gridwork may be suspended from wires or from special clip members
fastened to the overhead structure.
When systems of this type are installed, a desirable ceiling height
is established which will clear the lowest air ducts, utility
piping, plumbing, etc. and which will be higher than the highest
window and door frame openings. L-shaped wall angles are then
placed around the outer periphery of the room at this established
level. Each wall bracket, of course, must be placed at the same
level. In that neither the floor nor the existing overhead
structures are found to be level even in new construction, the
installer must utilize various leveling devices, chalk lines and
like tools in an attempt to establish a horizontal and level
reference plane. Generally, a transit is used to establish several
bench marks or reference points, and then a water level is used to
level the wall angles with respect to that point.
Wall angles are then fastened around the outer perimeter of the
room along this level horizontal plane and then the location of the
main grid runners must be established across the room. In an
average installation each individual panel measures approximately 2
feet by 4 feet with the main grid runners being spaced 4 feet
apart. In order to hang these runners, a string is stretched across
the room at the 4 foot intervals and hangers or suspension wires
are affixed to the joists or other upper support structure at no
greater than 4 foot intervals along the main runners. As the
hangers are affixed, they are bent at the level of the string.
When the hangers have been installed and bent, the string is
removed and the main runners are hung in place on the bent hangers
or suspension wires. A water level may be used in an attempt to
compensate for string sag. After the grid runners have been
installed and are leveled with the wall angles, cross "T"s are then
inserted between the main runners and finally the individual panels
are slipped into place.
In large commercial installations, however, it is often extremely
difficult to stretch the taut string across an area without having
a certain amount of sag present. Additionally, it is necessary to
either have a large amount of scaffolding or to move scaffolding
over the same area twice in order to first bend the wires and then
hang the runners. The two steps cannot be performed simultaneously
since the hung runners would interfere with the line of the string.
Finally, another problem is created when the hanger cannot be hung
directly above the string and directly above the ultimate position
of the hanger hole in the runner. It is pure guesswork for the
worker to bring the hanger wire down at an angle and bend it at the
proper level.
Thus, the difficulties involved in the preliminary render the
installation of this type of ceiling very costly.
SUMMARY OF THE INVENTION
The present invention comprises a method and apparatus which
greatly simplify the preliminary installation of wall angles and
runners by providing a method and apparatus for establishing a
"working" reference line for the installation of such a suspended
gridwork. Basically, the invention comprises a method and an
apparatus for projecting a collimated horizontal light beam,
preferably from a laser source, throughout the area in which a
suspended ceiling is to be installed. The light source may be
centrally positioned in an area and swept around the area. Targets
attachable to the gridwork structure are utilized to position the
structural members with reference to the light beam where they may
be fixed in place by attaching the suspending wires and bending
them to hold the structural members in predetermined positions.
The targets are provided with fastening means for quick attachment
and removal from the structural members. In one embodiment the
targets may be provided with an integral wire bending tool. In
another embodiment the target member is provided with a reflector
for use in areas where the ambient light is particularly high.
Finally, in another aspect of this invention, various structures
are provided for mounting and positioning the light beam source so
that it may be effectively utilized over a large area.
By various aspects of this invention, one or more of the following
or other objects can be obtained.
It is a primary object of the present invention to provide a method
and an apparatus for installing suspended ceilings.
It is another object of this invention to provide an apparatus for
utilization in the installation of suspended ceilings.
Another object of the present invention provides a "working" level
reference line to be utilized in conjunction with a target member
for the installation of suspended ceiling structures.
It is yet another object of this invention to provide a method and
apparatus for establishing a level base reference line around the
perimeter of a room for the installation of wall angle supports for
a suspended ceiling.
Other aspects, objects and the many advantages of this invention
will become apparent to one skilled in the art from a study of this
disclosure, the drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the
accompanying drawings in which:
FIG. 1 is a view illustrating the utilization of the method and the
apparatus of the present invention;
FIG. 2 is a top plan view of a mounting means for the light beam
projector of the invention;
FIG. 3 illustrates an alternate mounting means for the light beam
projector;
FIG. 4 is a view like FIG. 3 showing the light beam projector in an
extended position;
FIG. 5 is an elevational view of an adjustable holding ring for the
rotating light beam projector;
FIG. 6 is a perspective view of the laser light beam projector
showing the leveling ring mounted thereon;
FIG. 7 is an elevational view of the target member showing its
attachment to the supporting gridwork of a suspended ceiling;
FIG. 8 is a plan view of the target member;
FIG. 9 illustrates a target member similar to FIG. 8 having an
integral wire bending tool;
FIG. 10 is a side elevational view of a target member illustrating
an alternate embodiment of a holding means;
FIG. 11 is a side elevational view of the target of FIG. 9; and
FIG. 12 is a side elevational view of a target member attached to a
clip utilized in the construction of permanent ceilings.
PREFERRED EMBODIMENT OF THE INVENTION
Turning now to the drawings, FIG. 1 graphically represents the
method and the apparatus of the present invention. The laser beam
projector 10 is shown mounted within an area on any conveniently
located supporting structure such as a support column 12 extending
between the floor 14 and the overhead structure 16. A collimated
horizontal beam of laser light B is swept around the area and is
arranged to sweep at a predetermined level relative to the height
desired for location of the suspended main runner 18. Wires 20 are
fixed to the overhead structure in any convenient manner such as by
twisting one end around the supporting structure and around itself.
At their opposite ends wires 20 are passed through mounting holes
in the gridwork main runners 18. A target member 22 is attached to
the main runner 18 and is moved by the installer with the gridwork
until the desired level position is obtained with reference to the
projected laser beam B. The wire 20 passing through the hole in the
gridwork runner 18 may then be twisted around itself to prevent
downward movement of the gridwork and hold it in its level
position. Thus, the wires are bent and gridwork 18 is hung without
moving a given scaffold section 24. In the preferred embodiment,
the bending and hanging steps are simultaneous. However, in an
alternative embodiment, the wires can be bent before being passed
through mounting holes in gridwork 18. Even in this alternative,
scaffold 24 does not have to be moved around between steps.
FIG. 2 illustrates a convenient mounting bracket assembly 26 for
mounting the laser beam projector 10 on a supporting column 12 as
illustrated in FIG. 1. The bracket assembly has a pair of legs 28
and 30 extending at a right angle to each other and essentially
forming a V-shape. Each of the legs has a series of holes along its
length for adjustable engagement with a clamp member 32 which has
an adjusting screw 34 threaded therein. At the apex of the V formed
by the legs 28 and 30 a mounting ring 36 is fixed to engage and
hold the projector 10. The projector is securely held therein by
means of a lock screw 37 adapted to tighten against the projector
10 while it is held in a central opening 68 in the ring. The
mounting bracket, because of the adjustable feature of the clamp
members 32, may be easily adjusted to fit varying sizes and shapes
of support columns 12.
In large clear areas constructed without supporting posts 12 it may
be necessary to utilize a laser beam projector support mechanism as
illustrated in FIGS. 3 and 4. The support illustrated therein is
basically a tripod 38 having a plurality of legs 40. Each of the
legs is divided into an upper and lower section with the lower
section being telescopically received and slidable into and out of
the upper section. A mounting ring 36 having essentially the same
configuration as that shown in FIG. 2 is fixed centrally of the
tripod and rests on the top thereof on a mounting ring adjustment
assembly 42 which will be more fully described hereinafter. The
laser beam generator 10 is vertically mounted (FIG. 4) in the
support ring and held in position by the locking screw 37. The
height of the laser beam generator is adjustable by extending the
lower section of the legs 40 to the desired height, locking
sections of the legs to secure them at the desired position.
Referring to FIG. 5, the mounting ring adjustment assembly 42 will
be described in greater detail. The base portion 46 of the mounting
ring 36 is provided with a plurality of adjustment screws 47 (two
are shown, while four are preferable, spaced 90 degrees apart)
which are threadably received in the base 46. A base support member
48 is mounted on the tripod 38 as shown in FIGS. 3 and 4 or on a
mounting bracket 26 as illustrated in FIG. 2 below the mounting
ring 36. In either event the base may be fixed to its supporting
structure by means of a plurality of clamps 50 and screws 52 or in
any other conventional, well-known manner. Adjustment screw support
pads 54 are provided on the base 46 for the ends of the adjustment
screws. The adjustment screws 47 may be turned to position the
laser beam generator 10 in position such that the beam of light
emitted therefrom is horizontal and level.
The laser beam generator is illustrated in FIG. 6 and may be of the
type commercially available from Laser Alignment, Inc., of Grand
Rapids, Mich., and which is most fully disclosed in commonly
assigned, copending patent application Ser. No. 564 filed Jan. 5,
1970 and entitled, APPARATUS FOR GENERATING A PLANE OF LIGHT. The
laser itself is housed in an elongated tube 56 and is designed to
project a beam of light upwardly to a rotating prism arrangement 58
which bends the light at a 90.degree. angle and projects it
horizontally outwardly to sweep over the area in which the ceiling
gridwork is to be installed. The rotating prism assembly 58 and a
self-contained drive mechanism therefor are fixed to the elongated
tube 56 which houses the laser generator by means of a collar 60
held in place by fastening screws 62. A switch 64 is conveniently
provided to turn the mechanism off when the generator is not in
use.
A plurality of liquid filled levels 66 are mounted in a ring-like
member which is affixed to the elongated tube 56 of the laser
generator. The levels and ring are very precisely aligned with the
light beam of the laser and are used in conjunction with the
mounting ring adjustment assembly 42 illustrated in FIG. 5.
The preliminary setup of the laser beam generator is best
illustrated with reference to FIGS. 2 through 6 wherein the laser
generator is elevated to its desired height with respect to the
floor 14 and the overhead structure 16. The laser beam generator 10
may be located on a support post 12, on a tripod 38, or in any
other convenient fashion. The tube 56 is positioned in the opening
68 provided in the mounting ring 36 and once the prism assembly 58
is positioned at the desired height, the fastening screw 37 may be
tightened to secure the laser generator 10 therein by the tube
56.
The adjustment screws 47 are then turned in and out, moving the
laser generator with respect to the base support 48. When the
levels 66 indicate that the laser generator 10 is perfectly level
the knurled locking nuts 70 may be tightened against the base of
the mounting ring 46.
Referring now to FIGS. 7 through 12, the various alternative target
members 22, 22a, 22b and 22c will be described. The target is
basically a translucent screen 72 preferably made from reinforced
fiber glass approximately one-sixteenth of an inch thick. An opaque
line 74 is horizontally drawn across the middle portion thereof.
Fastening means 74 is attached to the upper portion of the screen
72 and is fixed by means of screws or rivets 78. The fastening
means illustrated in FIG. 7 may be of the magnetic type commonly
used for holding cabinet or cupboard doors closed. The magnetic
fastener is rapidly and easily applied to the metallic gridwork 18
and does not damage the surface while remaining tightly held
thereon.
The fastening means 74a illustrated in FIG. 10 on alternative
target 22b is affixed by screws or rivets 78 and is of the
"alligator" clip type with the opening between the jaws being
formed at a right angle to the plane of the target. This type of
fastener is particularly useful in installations wherein the
supporting gridwork is made from a non-magnetic material such as
aluminum. Also, it can be used by clipping it directly to the
handle of a pair of pliers. In the embodiment shown in FIG. 9, the
screen 72 of 22a is formed in a metal framework 80 and at one side
thereof is provided with extended tabs 82 having a slot or opening
84 therebetween. The tabs provide a convenient tool for bending and
tightening the wires 20 after the height of the gridwork is
established. Referring to FIG. 11, it can be seen that the tabs 82
are bent out of the plane of screen 72, in opposite directions.
This allows one to hold the target generally vertically while
moving it along a wire 20 with the wire 20 in position in slot
84.
Referring to FIG. 12, there is illustrated a resilient C shape clip
member 90 often utilized in a well-known manner to adjustably
support a channel iron 92 used in the construction of permanent
type ceilings, such as plaster ceilings. The clip 90 is provided
with an opening 94 in the back face of the C and is slidably
mounted along a rigid rod member 96 fixed to the overhead
structure. The target member 22c utilized in connection with clips
of this type may be provided with a tapered magnetic plug 98 which
is adapted for insertion in the opening 94 in the clip 90.
As a matter of convenience the opaque line 74 on the screen 72 is
precisely located two inches below the upper gridwork engaging
surface. A reflector 86 (FIG. 7) may be provided on one side of the
screen for use when ambient lighting conditions are extremely high.
The reflector has also been found to be extremely useful when
installing the wall angles to the outer perimeter of the room.
METHOD OF OPERATION
Referring again to FIG. 1, the laser beam generator 10 is centrally
positioned within the area in which the supporting gridwork for the
ceiling is to be installed. The generator may be mounted by means
of the bracket 26 (illustrated in FIG. 2) on the structural support
column 12 or it may be mounted in the tripod 38 illustrated in
FIGS. 3 and 4.
Once mounted, tube 56 is moved up or down with respect to mounting
ring 36 until rotating prism assembly 58 is positioned to emit a
laser beam at a desired level. The level selected has a
predetermined distance relationship to the ultimately desired
ceiling level. If target 22 of FIG. 7 is used, the prism assembly
58 is positioned to cast a beam in a reference plane which is the
same distance below the ceiling level as line 74 is from the top of
target 22. If target 22a is used, the reference plane for the
rotating laser beam will be at the same height as is ultimately
desired for the ceiling. This is because line 74 is directly in
line with the wire bending slot 84.
When the leveling adjustments are made as described in connection
with FIG. 5, the laser beam generator 10 is in condition to project
a horizontal level beam B of light around the area as the rotatable
prism 58 shown in FIG. 7 is set into operation.
The wall angles 19 are first set into position around the perimeter
of the area by simply attaching a target member 22 to the lower
edge of the angle and moving it into position such that the beam B
strikes the target. The wall angle and target are moved up or down
until the beam which presents a streak of light on the target is
exactly positioned on the opaque line 74. The bracket is then fixed
to the wall by suitable fastening means such as nails or adhesives.
Many installers may be working around the perimeter of the area
with complete assurance that each section of wall angle 19 will be
level and at exactly the same height with respect to each
other.
A section or runner of the supporting main runner 18 is then fixed
at one end to the wall angle 19 and extends outwardly therefrom
toward the opposite side of area. A supporting wire 20 is then hung
from any nearby convenient location on the superstructure 16 and
the free end of the wire is passed through a hole in gridwork
runner 18. A target 22 is attached to the gridwork runner 18 and is
moved into its proper level position by viewing the projected beam
of light through the transparent screen and moving the grid and
target until the streak of light is exactly in line with the opaque
line 74 as previously described. The supporting wire 20 is then
bent around the opening in gridwork runner 18 and is twisted to
hold it in place. Subsequent gridwork runners are added in line
with this previously hung runner. If desired, the target 22a
illustrated in FIG. 9 may be used for this bending operation. Slot
84 is slipped over wire 20 and target 22a is moved along until the
laser beam flashes across the face of screen 72 at the level of
line 74. At this point, target 22a is twisted such that the tab 82
bends wire 20. Then, main runner 18 is slipped over the end of wire
20, i.e., by passing wire 20 through a hole in main runner 18.
Finally, wire 20 is twisted around itself. While this procedure is
not quite as ideal as that set forth above, the invention can be
carried out in this fashion without the need for a great deal of
scaffolding or without having to move a section of scaffolding over
the same area twice. Operations may continue in this fashion until
the entire area is provided with level, aligned main gridwork
runners 18 at which time the cross T's and individual ceiling
panels may be set in place. During either of these operations many
installers working in the same area will be installing the
respective sections to exactly the same reference line, that is, to
the projected beam.
In order to make sure the main runners 18 are in proper alignment,
two techniques can be used. Both involve establishing a single
reference line or row relative to which all rows of runners 18 are
suspended. The first is to direct a laser beam directly across the
room along the desired line. The first row of main runners 18 are
suspended on this beam line. Subsequent lines of main runners 18
are then aligned by joining a cross T runner 18a of a given length
to the first row of runners 18 and to the particular runner 18
being suspended parallel thereto. In this fashion, the rotating
laser beam is used to establish proper elevation while proper line
is insured by the fact that the cross T's 18a are of identical,
fixed length and the first row of main runners 18 are known to be
in a straight line.
In the alternative, a taut string can be used to establish line for
the first row of main runners 18. It will be understood that this
string is used only for etablishing line for the first row, and is
not used at all to establish elevation.
The wall itself could be used as a first reference line if it were
erected using a laser beam. However, where this is not the case,
the wall will be crooked and one of the above two techniques must
be used to establish a proper line for the first row of gridwork
runners 18 erected. The cross T runners 18a from this first row to
the wall are then individually cut to appropriate lengths to reach
the wall.
It should be noted that in some applications the ceiling
superstructure will itself lie on a true line and the hanging wires
20 will hang vertically straight downward. Also, there will be
situations where the wires 20 will be mounted in anchors which are
somehow embedded in the ceiling. If the anchors are inserted on
line, as by using a laser beam, wires 20 will hang vertically on
the line desired for the main runners 18. When this is the case,
target 22a can be used to bend the wires and the runners 18 can be
slipped onto the wires 20 after they are bent.
In using target 22a, the vertically hanging wire is slipped into
slot 84. The target is slid along the wire until the laser beam
hits line 75. Then, the wire 20 is bent using slotted tab 82.
Target 22b of FIG. 10 can be used by clipping it to a runner 18 or
by clipping it to the handle of a pair of pliers. When clipped to a
runner 18, target 22b is used like target 22. When clipped to a
pliers' handle, it is used like target 22a.
Finally, target 22c of FIG. 12 is used by inserting its tapered
plug 98 into the opening 94 in clip member 90 and sliding the clip
along the rod member 96 until the laser beam sweeps across the
reference line 75.
As an actual practical demonstration of the utility of this
invention, a suspended ceiling was installed in a large discount
department store which was under construction. According to the
estimates of the foreman there was a 30 percent time savings alone
in overall installation time with a somewhat greater than 90
percent time savings in the leveling operation alone. Costs of
installing such suspended ceilings can be considerably reduced when
using the invention disclosed herein.
When ambient light conditions are high, the reflector 86 shown in
FIG. 7 serves to enhance the visibility of the streak of light
projected on the target. During normal conditions, however, the
light streak is viewed through the target. Unlike the normal
operations involved in installing suspended ceilings wherein the
taut strings and levels were used for alignment and leveling
requiring at least a certain amount of light for making
measurements, the present invention can be operated in an area
having minimal ambient light; in fact, the invention can be
operated in near total darkness.
Having thus described the invention, it will become immediately
obvious to those skilled in the art that the invention not only
provides a new, unique use for a laser, but additionally provides a
new and unique method and apparatus for installing supporting
structure for suspended ceilings. The method disclosed saves
considerable time in installation and leveling procedures with a
corresponding reduction in total labor costs.
Additional modifications and variations will naturally be suggested
to those skilled in the art without departing from the scope of the
invention which is defined by the following claims.
* * * * *