U.S. patent application number 09/963945 was filed with the patent office on 2002-06-20 for level.
Invention is credited to Schooley, Jack M..
Application Number | 20020073565 09/963945 |
Document ID | / |
Family ID | 23165892 |
Filed Date | 2002-06-20 |
United States Patent
Application |
20020073565 |
Kind Code |
A1 |
Schooley, Jack M. |
June 20, 2002 |
Level
Abstract
A level comprises a frame defining first and second parallel
channels and first and second rails fitted slidingly in the first
and second channels respectively. The level is adjustable in length
by sliding the rails in the respective channels of the frame.
Inventors: |
Schooley, Jack M.;
(Vancouver, WA) |
Correspondence
Address: |
KOLISCH, HARTWELL, DICKINSON,
McCORMACK & HEUSER
Suite 200
520 S.W. Yamhill Street
Portland
OR
97204
US
|
Family ID: |
23165892 |
Appl. No.: |
09/963945 |
Filed: |
September 24, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09963945 |
Sep 24, 2001 |
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09302014 |
Apr 29, 1999 |
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Current U.S.
Class: |
33/374 |
Current CPC
Class: |
G01C 9/28 20130101 |
Class at
Publication: |
33/374 |
International
Class: |
G01C 009/00 |
Claims
I claim:
1. A level adjustable between a retracted condition and an extended
condition, the level comprising: a frame including a first guide
surface and a guide member having a sliding surface; a rail
including a second guide surface and a slide having a sliding
surface, the rail mounted to the frame with the second guide
surface coplanar with the first guide surface, and with the sliding
surfaces of the frame and the rail contacting one another and
sliding relative to one another as the frame and rail are moved
between the retracted and extended conditions, wherein at least one
of the sliding surfaces is treated to prevent sticking; and an
indicator mounted to one of the frame and the rail, the indicator
readable by a user to determine if the guide surfaces are in either
a horizontal or a vertical position.
2. The level of claim 1 further comprising a biasing means coupled
to the rail and the frame, the biasing means urging the sliding
surfaces against one another to increase the friction between the
sliding surfaces and frictionally hold the rail and the frame in
any position between the retracted and extended conditions.
3. A level adjustable between a retracted condition and an extended
condition, the level comprising: a frame including a first guide
surface and a guide member; a rail including a second guide surface
and a slide, the rail mounted to the frame with the second guide
surface coplanar with the first guide surface, and with the slide
adjacent and slidable relative to the guide member between the
retracted condition and the extended condition; a first indicator
mounted to the frame, the first indicator readable by a user to
determine if the guide surfaces are in either a horizontal or a
vertical position; and a second indicator mounted to the rail, the
second indicator readable by a user to determine if the guide
surfaces are in either a horizontal or a vertical position.
4. A level adjustable between a retracted condition and an extended
condition, the level comprising: a frame including a first guide
surface and an upper guide member and a lower guide member, the
upper guide member defining a channel and including a sliding
surface, the other guide member having a leaf spring mounted
thereon; a rail including a second guide surface and a slide having
an upper sliding surface and a lower sliding surface, the rail
mounted to the frame with the second guide surface coplanar with
the first guide surface, and the slide disposed at least partially
in the channel, wherein one of the sliding surfaces of the rail
contacts the sliding surface of the frame and the other sliding
surface of the rail contacts the leaf spring, the slide moving
relative to the guide members as the frame and rail are moved
between the retracted and extended conditions; and an indicator
mounted to one of the frame and the rail, the indicator readable by
a user to determine if the guide surfaces are in a desired
orientation.
5. The level of claim 4 wherein the leaf spring biases the sliding
surface of the rail against the sliding surface of the frame to
frictionally hold the rail and the frame in any relative position
between the retracted and extended conditions.
6. The level of claim 4 wherein the leaf spring includes two wings
extending from a central mount.
Description
Related Application
[0001] This application is a continuation of and claims priority to
U.S. Patent Application Serial No. 09/302,014, filed Apr. 29, 1999
for "Level," issuing Sep. 25, 2001 as U.S. Pat. No. 6,293,023.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] This invention relates to a level.
[0003] The conventional carpenter's level, which is used for
testing whether a nominally horizontal (or vertical) surface is in
fact horizontal (or vertical), within an acceptable tolerance,
comprises a frame, typically made of a metal such as aluminum
alloy, having at least one flat guide surface and two bubble vials
mounted in the frame. The level is positioned with the guide
surface against the surface to be tested. One vial is oriented
relative to the guide surface for testing a nominally vertical
surface and the other is oriented for testing a nominally
horizontal surface. The typical level is about 2 feet long,
although longer levels, e.g. four feet or six feet long, are also
available.
[0004] The fact that conventional levels are available only in
increments of about 2 feet in length gives rise to difficulty or
inconvenience in using the conventional level. Imagine, for
example, that you are installing a shelf inside a closet having a
back wall about 3'6"wide between two side walls. You wish to attach
a support to the back wall for supporting the rear edge of the
shelf. The support should be horizontal, and you wish to mark the
position of the support at two locations, adjacent the side walls
respectively. Obviously, since the back wall is only 3'6"wide, you
cannot use a four foot level because there is not sufficient
space
Summary of the Invention
[0005] In accordance with the invention there is provided a level
comprising a frame defining first and second parallel channels, and
first and second rails fitted slidingly in the first and second
channels respectively, whereby the level is adjustable in length by
sliding the rails in the respective channels.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] For a better understanding of the invention, and to show how
the same may be carried into effect, reference will now be made, by
way of example, to the accompanying drawings, in which
[0007] FIG. 1 is a perspective view of a level in accordance with
the invention in a retracted condition,
[0008] FIG. 2 is a similar view of the level in a partially
extended condition,
[0009] FIG. 3 is a perspective exploded view of the level.
Detailed Description
[0010] The illustrated level comprises a frame 2 and two rails 4A
and 4B. In the following description, the suffix A or B is used
when it is necessary or helpful to distinguish between the two
rails or elements that are associated with the two rails.
Otherwise, no suffix is used.
[0011] The frame 2 is made from a length segment of an aluminum
alloy extrusion and is generally I-shaped in cross-section, having
two spaced parallel guide members 8 connected by a web plate 12 so
that two channels 20 are defined on opposite sides respectively of
the web plate 12. Each member 8 has at each edge a lip or flange 16
projecting toward the other member 8. The frame has two parallel
guide surfaces 24, only one of which can be seen in the
drawings.
[0012] Each rail 4 includes a slide 28 and a frame extender 32
which is attached to the slide.
[0013] The frame extender 32 is made of a length segment of the
same extrusion as is used to make the frame 2 and consequently it
includes two parallel guide members 36 and a web plate 40. The
guide members 36 and the web plate 40 define two channels 42, 44 on
opposite sides respectively of the web plate 40. Each guide member
36 has at each edge a lip or flange 52 projecting toward the other
guide member 36. The frame extender has two parallel guide
surfaces.
[0014] Each slide 28 includes a web plate 46 and two flanges 48
which extend perpendicular to the web plate 46. The slide has a
rebate 60 at the base of each flange. The cross-sectional
configuration of the slide is selected relative to that of the
channels of the frame extender so that the slide 28 can be inserted
in the channel 42 in only one orientation, and in this orientation
the web plate 46 of the slide is held away from the web plate of
the frame extender by the flanges 48. The slide 28 is retained in
position relative to the frame extender by pins (not shown). The
slide does not obstruct the channel 44. Each rail also includes an
end cap 50, which is attached to the frame extender and the
slide.
[0015] The cross-sectional configuration of the slide 28 also
allows the slide to be inserted in the channel 20 of the frame with
the web plate 46 of the slide held away from the web plate 12 of
the frame 2 by the flanges 48. The slide constrains the frame
extender into alignment with the frame 2, with the two guide
surfaces of the frame extender coplanar with the guide surfaces 24
of the frame. The slide 28 is slidable in the channel 20, allowing
adjustment in the length of the level between a retracted
condition, in which the frame extenders abut the frame 2, as shown
in FIG. 1, through a partially extended condition, shown in FIG. 2,
to a fully extended condition in which only a relatively short
segment of the length of the slide is accommodated in the channel
20.
[0016] The length of each slide 28 is approximately equal to the
sum of the length of the frame 2 and the lengths of the two frame
extenders 32. The slide of the rail 4A then extends through the
channel 20A of the frame 2 and into the channel 44 of the rail 4B
when the level is in the retracted condition. This allows the
maximum difference in length between the retracted condition and
the fully extended condition.
[0017] The frame also includes, in each channel 20, biasing means,
such as leaf springs 52 (only the leaf springs 52A are shown). The
leaf springs 52A are attached to the lower guide member 8A and urge
the slide 28A toward the upper guide member 8B. Conversely, the
leaf springs in the channel 20B are attached to the upper guide
member 8B and urge the slide 28B toward the lower guide member 8A.
The leaf springs take up clearance between the slides 28 and the
frame 2. As shown in FIG. 3, leaf springs 52 preferably are formed
of a single strip and include two wings 74, 76 extending from a
central mount 72 in guide member 8A. Central mount 72 may include
two rivets 73, 75 for affixing springs 52 in place. Slides 28
include a sliding surface 49L that abuts and slides against leaf
spring 52 as the level is moved between the retracted and extended
conditions. Slides 28 include a sliding surface 49U that directly
contacts and slides against a sliding surface 21U in guide member
8B. Springs 52 urge sliding surfaces 49U of slides 28 and sliding
surfaces 21U of guide member 8B together. Springs 52 increase the
friction between the sliding surfaces which frictionally holds the
level in any relative position between and including the retracted
and extended conditions.
[0018] The web plate 12 is formed with an aperture in which two
indicators, such as bubble vials 56 are mounted. One of the vials
is oriented for testing a vertical surface and the other is
oriented for testing a horizontal surface. The bubble vials 56
project from the web plate 12 into the channels 20 of the frame 2.
Since the web plate 46 of the slide 28 is held away from the web
plate 12 of the frame 2 by the flanges 48, the web plate 46 remains
clear of the bubble vials 56 when the slide is inserted in the
channel 20. Similarly, the web plates 40 are each formed with an
aperture in which two bubble vials 58 are mounted. The bubble vials
58 project from the web plate 40 into the channels 42, 44 of the
frame extender. Since the web plate 46 of the slide 28 is held away
from the web plate 40 of the frame extender by the flanges 48, the
web plate 46 of the slide 28 remains clear of the bubble vials 58.
Moreover, when the level is compressed from its extended condition
to its retracted condition, and the slide 28 of one rail enters the
channel 44 of the other rail, the web plate 46 remains clear of the
bubble vials 58 of the other rail. The bubble vials 58 are thereby
protected from damage by impact with the slide.
[0019] The web plates 12 and 46 are formed with openings which
serve to reduce the weight of the level and facilitate gripping and
handling of the level. The openings also provide viewing access to
the bubble vials, so that regardless of the degree of extension of
the level, the user can see at least one vial oriented for testing
a vertical surface and one vial oriented for testing a horizontal
surface.
[0020] The manner of use of the level, for testing a nominally
vertical or nominally horizontal surface, or for marking segments
of a horizontal or vertical line on a vertical surface, will be
well understood by a person skilled in the art.
[0021] In use of the level illustrated in the drawings, for example
in a confined space, the user extends the rails from the frame
sufficiently to span the desired distance without interference with
other structures, and the user can then determine whether a
nominally horizontal (or vertical) surface is in fact horizontal
(or vertical) or can mark a horizontal (or vertical) line on a
vertical surface between two structures that would interfere with a
longer level. Further, it is possible to manipulate the level into
a confined space in its retracted condition and then extend it for
use, e.g. in marking a vertical or horizontal line on a wall.
[0022] It will be appreciated by those skilled in the art that
under some conditions aluminum does not slide smoothly against
aluminum but sticks due to galling. Various treatments are
available for relieving galling.
[0023] It will be appreciated that the invention is not restricted
to the particular embodiment that has been described, and that
variations may be made therein without departing from the scope of
the invention as defined in the appended claims and equivalents
thereof.
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