U.S. patent number RE30,020 [Application Number 05/903,361] was granted by the patent office on 1979-06-05 for foldable work platform.
This patent grant is currently assigned to Little Giant Industries Inc.. Invention is credited to Edward Spencer, Harold R. Wing.
United States Patent |
RE30,020 |
Spencer , et al. |
June 5, 1979 |
Foldable work platform
Abstract
An improved foldable work stand and platform having an upper
work support surface with wooden inserts therein to protect saws
and the like from being damaged by accidental contact with the
metal structure of the platform. The foldable work platform also
includes improved structure for elevating the working surface and
an adjustable stabilizer leg to maintain the work surface generally
horizontal on uneven terrain. Lateral extensions of the work
surface provide versatility in the work surface configuration and
are easily secured in a selected orientation.
Inventors: |
Spencer; Edward (La Grange,
IL), Wing; Harold R. (Springville, UT) |
Assignee: |
Little Giant Industries Inc.
(American Fork, UT)
|
Family
ID: |
24778530 |
Appl.
No.: |
05/903,361 |
Filed: |
May 5, 1978 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
691926 |
Jun 1, 1976 |
04031981 |
Jun 28, 1977 |
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Current U.S.
Class: |
182/153;
182/182.1; 182/182.4; 182/182.5; 182/227; 248/167; 248/188.6 |
Current CPC
Class: |
E04G
1/34 (20130101) |
Current International
Class: |
E04G
1/00 (20060101); E04G 1/34 (20060101); E04G
001/32 (); F16M 011/00 () |
Field of
Search: |
;182/153,154,181,182,183,184,185,186,224,225,226,227
;248/188.6,167,436 ;269/296 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Machado; Reinaldo P.
Attorney, Agent or Firm: Workman; H. Ross Nydegger; Rick
D.
Claims
What is claimed and desired to be secured by United States Letters
Patent is:
1. A foldable work platform comprising in combination:
a base comprising two upright, hollow legs rigidly interconnected
by a cross piece and a support stand rotatably attached to the
cross piece for selectively giving stability to the base when in
upright position;
a scaffold adjustably cooperating with the base and comprising two
downwardly depending hollow members rigidly interconnected by an
open cross channel, each member being telescopically received by a
leg, and means for securing each leg and hollow member
together;
an arm configurated as an open U-shaped channel rotatably and
extensibly carried upon the scaffold at at least one end thereof;
and
wooden inserts nested within the cross channel and arms, the
inserts extending above the sides of the channels.
2. A foldable work platform as defined in claim 1 wherein said
support stand is vertically extensible to give stability to the
base on uneven terrain.
3. A foldable work platform as defined in claim 1 wherein said
wooden inserts are removably mounted upon the cross channel.
4. A foldable work platform as defined in claim 1 wherein said
wooden inserts are removably mounted upon the arm.
5. A foldable work platform as defined in claim 1 wherein said
means for securing each leg and hollow members together comprises
means for positively interlocking the leg and hollow member.
6. A foldable work platform as defined in claim 1 wherein said
scaffold comprises laterally extending support means for receiving
the arms in nesting relationship in at least two orientations in
which lateral displacement of the arm is limited.
Description
BACKGROUND
1. Field of the Invention
The present invention relates to foldable work platforms.
2. The Prior Art
Conventional work platforms are commonly referred to as saw horses.
Saw horses are commonly rigidly constructed from wood and present a
wooden surface upon which boards and the like are placed for
cutting and/or fabrication. Often saw horses are constructed on a
job site because of their awkward shape and the attendant
difficulty with which they are transported.
One of the most persistent problems, however, is the common
practice of inadvertently cutting through the saw horse as boards
thereon are being cut. When cut through, the saw horse is worthless
and another must be constructed thereby incurring significant cost
of time and materials.
Foldable work platforms for use as extensible support stands and
surfaces for workpieces are known in the art. One prior art work
platform is manufactured in West Germany and is sold under the
trademark of WAKU and distributed by Cross State Sales, Inc. of
Salt Lake City, Utah. The upper surfaces of the prior art work
platform are, however, fabricated from metal stock and covered with
a thin, rubberized mat surface. Experience has revealed that using
a work platform with a metal surface frequently damages saws and
other tools and the like when a board is accidentally cut through
striking the upper metal surface of the work platform.
In view of the foregoing, it would be an advancement in the art to
provide a foldable, extensible work platform which is more easily
manipulated, has improved stability, and provides a surface which
will not damage saws and the like if the same are accidentally
brought into contact with the upper surface thereof. Such an
invention is disclosed herein.
BRIEF SUMMARY AND OBJECTS OF THE INVENTION
The present invention relates to an improved metal work platform
which is foldable into a generally flat configuration and includes
replaceable wooden inserts for the working surfaces thereof. The
wooden inserts extend above the adjacent metal parts of the
platform to intercept saws or other cutting tools to prevent or at
least minimize damage from accidentally striking the upper surfaces
of the platform. The wooden inserts and the corresponding receiving
areas of the platform are specifically designed to accommodate
replacement. Novel interlock structure permits the workpiece to be
secured in any one of a variety of work surface configurations.
Accordingly, it is the principal object of this invention to
provide improvements in foldable work platforms.
It is another object of this invention to provide a foldable work
platform with a replaceable wooden insert for the working surface
thereof.
Another object of this invention is to provide improvements in the
smooth operation and stability of an extensible, foldable work
platform.
These and other objects and features of the present invention will
become more fully apparent from the following description and
appended claims taken in conjunction with the accompanying
drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective illustration of the work platform of this
invention in a first, folded position, the wooden inserts having
been removed to reveal underlying structure;
FIG. 2 is a perspective illustration of the work platform of this
invention in one operative position, a workpiece illustrated in
broken lines being clamped thereon;
FIG. 3 is a perspective illustration of the work platform of this
invention in another operative position with a workpiece
illustrated thereon in broken lines;
FIG. 4 is a fragmentary plan view of one portion of the work
platform with wood inserts removed; and
FIG. 5 is a fragmentary schematic perspective illustration of one
portion of the work platform of this invention in transition from
one position to another.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention is best understood by reference to the figures
wherein like parts are designated with like numerals
throughout.
Referring now to the drawing, the work platform is shown generally
at 10 and includes a base 12, a support stand 20 and a scaffold
50.
Base 12 is generally configurated in the form of the letter H and
includes vertical legs 14 and 16 which are formed from hollow metal
tubes securely welded to a horizontal diametrally piece 18. The
hollow tubes give the required strength and also give the work
platform 10 a lightweight character. Lateral stability for base 12
is provided by a support stand 20 likewise formed of hollow tubular
material. Support stand 20 further includes downwardly extending
legs 34 and 36. Legs 34 and 36 terminate in feet 38 and 40,
respectively which are preferably caps of non-skid rubber. Support
stand 20 is rotatably and extensibly coupled to cross piece 18 with
a hollow sleeve 28 welded or otherwise suitably permanently mounted
upon cross piece 18. Hollow sleeve 28 telescopically receives a
diametrically reduced neck 26 of support stand 20. The neck 26 is
permanently joined to the stand 20 intermediate the length hereof
and projects vertically upward. A set screw 30 is used to
releasably lock the neck 26 in collar 28 and thereby accommodate
setting the desired rotational position of support stand 20 with
respect to base 12. It is also observed that the neck 26 is
elongated to permit extension thereof out of the collar 28. Thus,
on uneven terrain the stand 20 may be extended into ground
engagement so that the stand 20 and one of the legs 14 or 16 will
maintain the work platform 10 upright even if the other of the legs
14 or 16 does not engage the ground because of the uneven
terrain.
Legs 14 and 16 terminate in a foot 22 and 24, respectively, each of
which is a cap of non-skid rubber. Additional support between the
legs 14 and 16 and the cross piece 18 is obtained by diagonal
braces 42 and 44, respectively. The upper end of legs 14 and 16 is
open to receive telescoping tubes 46 and 48 forming part of
scaffold 50. The vertical height of the scaffold 50 may be adjusted
by telescoping or extending the tubes 46 and 48 from the
corresponding legs 14 and 16. Thumb screws 52 and 54 provide
securement for the relative positions of the legs and tubes.
Because the work platform may be required to support considerable
weight, a positive interlock is desirable. Therefore, each tube 46
and 48 is provided with a plurality of apertures 56-58 into which
thumb screws 52 and 54 advance so as to provide positive interlock
between the legs 14 and 16 and corresponding tubes 46 and 48.
Scaffold 50 is constructed of a pair of support brackets 96 and 98
which are channel members opening upwardly. The tubes 46 and 48 are
welded or otherwise suitably attached to the brackets 96 and 98,
respectively, intermediate the length thereof. Each bracket 96 and
98 has an intermediate portion 55 from which the upstanding sides
72 and 75 of the channel member have been cut away. A through-bore
57 in the base of each bracket 96 and 98 is aligned with the
corresponding tube 46 or 48 for a purpose hereinafter more fully
described.
Each bracket 96 and 98 has a corresponding laterally extending
support element 68 and 70 which projects beyond the legs 14 and 16
and which is separated from the remainder of the bracket 96 or 98
by intermediate portion 55. Angle braces 88 and 90 are welded or
bolted between the tubes 46 and 48 to give vertical integrity to
the brackets 96 and 98, respectively.
Cross channel 53 traverses the space between brackets 96 and 98 and
is welded or otherwise permanently secured thereto. Cross channel
53 is configurated as an upwardly open channel having side walls 80
and 82 and in accordance with the present invention, receives a
wooden insert 51 in nesting relationship, said insert 51 having a
vertical dimension sufficient to extend above side walls 80 and 82
(see FIG. 3). It is presently preferred that at least half of the
depth of the insert 51 project above the side walls 80 and 82. The
insert 51 is illustrated as a wooden strip which is square in cross
section and has a typical dimension of 2 inches (5.08 cm) square.
Clearly, any suitable alternative dimensions could be used. The
portion of insert 51 which is exposed above the cross channel 53
absorbs the inadvertent cuts and blows of saws or other tools and
thus reduces damage to the tools which might otherwise result if
the saw should strike a metal surface.
The versatility of the scaffold 50 is dramatically increased with
the addition of rotatable arms 60 and 62. The arm 60 is an upwardly
opening channel member having a depending shaft 64 mounted at the
bottom thereof near one end. Arm 62 is similarly configurated and
has a corresponding shaft 66 mounted adjacent one end thereof. Each
of the shafts 64 and 66 has a substantial axial length which
projects into the hollow of corresponding tubes 46 and 48. In the
illustrated embodiment, the shafts 62 and 64 are rotatable within
the corresponding tubes and, in addition, are telescopically
extensible and retractable into and out of the corresponding tubes
46 and 48. The movability of the arms 62 and 60 permits the arms to
be placed in any one of a plurality of desirable positions as
illustrated in FIGS. 2-5 and as will be hereinafter more fully
described. Once the position of the arms has been determined, the
position is fixed by advancing thumb screws 92 and 94 through tubes
46 and 48, respectively so as to form a friction-securement of the
thumb screws against the shafts 64 and 66.
The lateral dimension of the arms 60 and 62 is substantially the
same as the lateral dimension of cross channel 53. Accordingly, the
arms 60 and 62 will not nest within the cross channel 53 even when
the wood insert 51 (FIG. 5) has been removed. However, it is
observed that the laterally extending support elements 68 and 70
are slightly larger in width than the lateral dimension of the arms
60 and 62. Accordingly, as shown at the right side of FIG. 2 each
arm will nest securely between the upstanding sides 72 and 74 of
the corresponding support element. It is also observed that the
open space at the intermediate portion 55 will receive arms 60 or
62 at right angles generally as shown in FIGS. 3 and 4. The
upstanding sides of the brackets 96 and 98 will continuously
maintain the arms 60 and 62 in either the laterally projecting
position illustrated at the right side of FIG. 2 or the essentially
right angle orientation as illustrated in FIGS. 3 and 4. The thumb
screw 92 or 94 will prevent vertical extension of the arm except
when desired for movement into a selected position as shown in FIG.
5.
Both of the arms 60 and 62 have corresponding wood inserts 61 and
63 which have substantially the same cross section as the insert 51
(see FIG. 3). The length of the wood inserts 61 and 63 is selected
to be substantially identical to the length of the arms 60 and
62.
Each of the inserts 51, 61 and 63 are replaceable within their
corresponding channel elements. Referring particularly to FIG. 4,
it is pointed out that cross channel 53 is provided with a
plurality of elongated slots 84 at spaced locations along its
entire length, only one slot being illustrated in FIG. 4. The
elongated slots 84 permit wood screws (not shown) to threadedly
engage and secure the insert 51 when the insert is nested within
the channel 53. Arm 62, as shown in FIG. 4, is also provided with
elongated slots 85 and 86 similarly adapted to receive wood screws
(not shown) to secure insert 63 between the upper right sides 76
and 78 of the arm 62. While a specific illustration of the
securement of the insert 61 to the arm 60 is not illustrated, it is
understood that the insert 61 is similarly secured to the arm
60.
The advantage of the mentioned securement is that the inserts may
be easily removed by simply removing the corresponding screws and
lifting the insert from its corresponding channel member. Thus,
damaged inserts can be simply and quickly replaced with little
waste of material and time.
The mode of operation of the work platform 10 will now be
described. For transport and storage, the platform 10 is preferably
folded as illustrated in FIG. 1. In this folded configuration, the
platform is essentially planar and because of its lightweight
construction can be easily moved from place to place and stored
with little difficulty. In order to properly use the platform,
transverse stability is afforded when the support stand is rotated
about the longitudinal axis of the neck 26 within the sleeve 28.
Rotation is accommodated by loosening the set screw 30 and manually
twisting the support stand 20 into position. While the support
stand 20 is illustrated at an essentially right angle orientation
with respect to cross piece 18, it should be appreciated that any
reasonable orientation of the support stand 20 may be used as long
as it gives the desired stability. On sloping or uneven terrain,
the neck 26 may be extended from within the sleeve 28 to assure
that at least three of the feet 22, 24, 38 and 40 solidly engage
the ground.
The normal operational position of the work platform 10 is to place
the arms 60 and 62 in outwardly projecting positions as shown at
the right side of FIG. 2 or, alternatively, in the right angle
positions as illustrated in FIG. 3. To position the arms in the
described orientation from the folded position illustrated in FIG.
1, thumb screws 92 and 94 are loosened to permit extension of the
arms as shown in FIG. 5 and, simultaneously, to permit rotation of
the arms into either the illustrated right angle position (FIG. 3)
or the coextensive position (the right hand side of FIG. 2). It is
noted that the described structure permits rotation of the arms 60
and 62 through 360.degree., if desired. When the arm has been
oriented according to the desired position, the shaft 66 is
telescoped into the tube 48 and the thumb screw 94 tightened to
hold the position of the arm 62. The bracket 98 including
upstanding sides 72 and 74 will prevent inadvertent rotation about
the axis of shaft 66 even if the thumb screw 94 should fail to hold
the arm 62 in position.
The work platform may be used in a variety of ways to support a
workpiece. For example, as shown in FIG. 2, a workpiece 100 may be
placed upon the upper work surface of insert 51 and held tightly in
place by first extending the arm 60 from within the tube 46, then
rotating the arm 60 so as to be superimposed over the workpiece 100
and thereafter lowering the arm 60 into tight engagement with the
workpiece 100. If desired, tightening of the thumb screw 92 will
assist to hold the workpiece 100, the arm 60 and the work surface
provided by insert 51 forming a clamp to hold the workpiece 100. As
shown in FIG. 3, the workpiece may be placed upon the arms 60 and
62 located at essentially a right angle to thereby present a
generally flat work surface defined by the wood inserts 61, 51 and
63. It has also been found desirable to use the work platform 10 in
tandem with another similar work platform in the same general way
in which saw horses have heretofore been used.
In the course of continued use of the work platform 10, it is
likely that the wood inserts 51, 61 and 63 will become damaged as
tools are used on the workpieces 100 and 102. As shown in FIG. 4,
however, the damaged inserts 51, 61 and 63 can be easily replaced
with corresponding inserts by simply removing the screws passing
through slots 84-86, removing the old damaged inserts and replacing
with substitute, undamaged wood inserts.
The invention may be embodied in other specific forms without
departing from its spirit or essential characteristics. The
described embodiments are to be considered in all respects only as
illustrative and not restrictive and the scope of the invention is,
therefore, indicated by the appended claims rather than by the
foregoing description. All changes which come within the meaning
and range of equivalency of the claims are to be embraced within
their scope.
* * * * *