Note: Descriptions are shown in the official language in which they were submitted.
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1 HEAVY DUTY, KNOCK-DOWN SAWHORSE
2 WITH LEVELING CAPABILITY
3
4 FIELD OF THE INVENTION
Embodiments of the present invention relate to sawhorses, more
6
particularly to heavy duty, knock-down sawhorses having removable legs and
7 leveling capabilities.
8
9 BACKGROUND OF THE INVENTION
Sawhorses of one type or another have been used by carpenters and
11 others
for many centuries and most everyone is aware of the typical sawhorse
12 having
a horizontal beam supported at opposing ends by a pair of legs. As one
13 skilled
in the art would understand, the dimensions of the sawhorse can be altered
14 to suit particular needs.
The need for a sawhorse is often a temporary one, and between uses
16 it is
convenient to knock-down the sawhorse to a more compact and portable form.
17 A knock-
downed form allows the sawhorse to be transported more easily to where it
18 is
needed so that it can be re-assembled for use. Typically, assembly and
19 disassembly of knock-down sawhorses involved clamps, bolts, screws and
nails.
US 4,014,405 to Breisch discloses a knock-down sawhorse which can
21 be
assembled without the use of bolts, screws, nails, or clamps. Breisch teaches
22 two
pairs of identical legs that each cooperatively fit within a recess along a
bottom
23 of a
horizontal beam. The horizontal beam is supported at each end by a pair of the
CA 02763238 2012-01-05
1 identical legs. The cooperating legs securely fit within the recess
without the use of
2 bolts, screws, nails or clamps. Breisch's sawhorse is composed of
thermoplastic
3 and its legs are not adjustable for leveling the horizontal beam.
4 US 5,305,850 to McQuiston teaches a horizontal beam having
grooves at opposing ends for receiving a corresponding pair of legs.
McQuiston's
6 knock-down sawhorse obviates the need for bolts, screws, nails or clamps
for
7 assembly of the sawhorse. Similar to Breisch, McQuiston's legs are not
adjustable
8 for leveling the horizontal beam.
9 Very popular in recent times have been the folding or collapsible
type
sawhorses. As disclosed in US 4,296,834 to Kroger, a folding sawhorse
typically
11 has a horizontal beam supported by a pair of legs at each opposing end
of the
12 horizontal beam. The two pairs of legs are each pivotally connected to
the
13 horizontal beam to allow the pair of legs to pivot longitudinally
towards the
14 horizontal beam, thereby collapsing the sawhorse for storage or
transportation.
Collapsible sawhorses obviate the need to disassemble and re-assemble a
16 sawhorse when storing, transporting or using it.
17 US 4,804,064 to Coultrup et al. teaches a lightweight collapsible
18 sawhorse that is vertically adjustable. Each of the four legs used in
Coultrup's
19 sawhorse is telescopically adjustable in length, allowing a user to
adjust a working
height of the sawhorse at each end for leveling the sawhorse. Coultrup's
telescopic
21 legs can be locked into or released from a position by the use of spring
tabs which
22 permits a user to level the sawhorse on uneven working surfaces. As a
result, a
2
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1 maximum load bearing capacity of Coultrup's sawhorse is diminished and
limited,
2 not by the load bearing capacity of the support legs, but by the load
bearing
3 capacity of the spring tabs used to lock each leg in a particular
position.
4 US 5,908,182 to Stang et. al. discloses an adjustable and foldable
sawhorse that is also capable of being leveled. Stang's sawhorse comprises a
6 horizontal beam supported at both opposing ends by A-shaped frames and a
7 support frame having two vertical posts interconnecting the two A-shaped
frames.
8 Each A-shaped frame is movably supported on the vertical post of the
support
9 frame and can be independently adjusted in height to level the sawhorse
on uneven
working surfaces. Similar to Coultrup's sawhorse, the load bearing capacity of
11 Stang's sawhorse is diminished and limited, not by the load bearing
capacity of the
12 support legs, but rather by the load bearing capacity of the support
frame.
13 There is a need for a heavy duty commercial sawhorse that is
easily
14 stored, adjustable and is capable of being leveled while maintaining its
maximum
load bearing capacity.
16
17
3
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1 SUMMARY OF THE INVENTION
2
Embodiments of a heavy duty, knock-down sawhorse can have a
3 beam
that is supported at opposing ends by a pair of splayed legs. Each opposing
4 end of the beam has a pair of connectors for removably connecting to a
corresponding leg. Each leg fully engages the beam for equally distributing a
load
6 between each of the legs supporting the beam.
7 The
legs of each pair of legs are spaced apart from one another by an
8 adjuster for adjusting a lateral spacing therebetween. The adjuster can be
9
manipulated to increase or reduce the lateral spacing between each of the
laterally
splayed pair of legs, thereby adjusting a working height of the sawhorse. When
the
11
adjuster increases the lateral spacing, a working height of the sawhorse is
reduced.
12
Similarly, when the adjuster decreases the lateral spacing, the working height
of the
13
sawhorse is increased. Adjustment of the lateral spacing between the legs at
each
14 end allows a user to level the sawhorse when working on uneven surfaces.
In a broad aspect of the invention a heavy duty, knock-down sawhorse
16 has a
beam having a longitudinal extent and lateral sides. At least a first pair of
17 legs
support a first end of the beam above the ground, while at least a second pair
18 of legs
support a second end of the beam above the ground. Each leg has an
19 upper
end having an axially-extending recess formed therein bounded by end walls
for engaging at least four connectors arranged along the beam.
21 At
least a first pair of connectors and at least a second pair of
22
connectors are arranged on the opposing lateral sides of the beam, the at
least first
4
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1 pair of connectors being longitudinally spaced apart from the at least
second pair of
2 connectors. Each connector further comprises a tab extending downwardly
from
3 the beam and engages the axially-extending recess of a corresponding leg for
4 supporting the beam above each leg.
Each pair of legs is splayed apart at an angle from the beam for
6 forming the sawhorse.
7
8 BRIEF DESCRIPTION OF THE DRAWINGS
9 Figure 1A is side view of an embodiment of the present invention
illustrating a heavy duty, knock-down sawhorse having a horizontal beam being
11 supported at both ends by a pair of legs;
12 Figure 1B is an end view of the sawhorse of Fig. IA illustrating a
13 turnbuckle for adjusting the height of one end of the sawhorse;
14 Figure 2 is a perspective view of one end of an embodiment of the
sawhorse illustrating a connector tab depending downwardly from a horizontal
16 beam and a leg poised for connecting with the tab;
17 Figures 3A through 3C illustrating one embodiment of the step for
18 forming one of a pair of connector tabs, and more particularly: cutting
a first vertical
19 slot in a lateral side, cutting of a second vertical slot spaced
longitudinally from the
first slot, and removing of base material for interconnection of the first and
second
21 slots and opening the tab for receiving a tubular leg respectively. Fig.
3C further
22 illustrates a cross-section upper end of a leg oriented for connecting
therewith;
5
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1 Figure
3D is a perspective, underside view of a portion of the
2 horizontal beam having the connector tabs;
3 Figure
3E is a perspective, end view of a portion of a channel-shaped
4
horizontal beam having the connector tabs formed therein and periodic bottom
wall
inserts;
6 Figure
4 is a cross-sectional view of a horizontal beam through the
7
connector tab and illustrating cross-sections of a pair of tubular legs, one
engaged
8 with a tab and the other poised for engagement with an opposing tab;
9 Figures
5A and 5B are end views of the sawhorse of Fig. 1A
illustrating the use of a turnbuckle for adjusting the height of one end of
the
11 sawhorse, from a lowered position to a raised position respectively;
12 Figure
5C is view of the horizontal beam and two of the legs of a
13 disassembled sawhorse of Fig. 1A; and
14 Figures
6A and 6B are cross-sectional views of the connectors of one
end of the horizontal beam of Figs. 5A and 5B respectively through the
connector
16 tab and illustrating the variation of the connection during height
adjustment;
17
18 DETAILED DESCRIPTION OF THE INVENTION
19 With
reference to Fig. 1A and 1B, an embodiment of a heavy duty
sawhorse 10 comprises a support beam 20 having a longitudinal extent and
lateral
21 sides,
which is generally horizontal when oriented for use, supported by a first pair
22 of
independent legs 30 adjacent a first end 40 of the support beam 20 and a
second
6
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1 pair of
independent legs 50 adjacent a second end 60. The support beam 20 has
2 an upper
surface 70 adapted to receive a heavy load or workpiece, supported off of
3 a floor,
ground or other base B by the first and second pairs of legs 30,50. The first
4 pair of legs 30 extend downwardly to engage the base and are splayed apart
laterally in an upside down "V" shape. Similarly, the second pair of legs 50
extend
6 downwardly and are also splayed laterally in an upside down "V" shape. The
7 splayed
provide both support and lateral stability. A longitudinal spacing S of the
8 first
and second pairs of legs 30,50 provides longitudinal stability. The first and
9 second
pairs of legs 30,50 need not be located at the ends of the support beam 20,
but merely spaced apart therealong.
11 Each
independent leg 80 is removably and lockably connected to the
12 support
beam 20 for permitting easy knock-down of the sawhorse 10 for storage or
13
transportation. Each of the two legs 80,80 of each pair of legs 30,50 are
adjustably
14 spaced
apart by an adjuster 90 for adjusting a lateral spacing between the two legs.
With reference to Fig. 2, the support beam 20 has two opposing lateral
16 sides, a
right side and a left side. The support beam 20 further comprises at least
17 four
connectors arranged along the beam 20. A connector tab 100 is provided for
18 each leg
80, a first pair of tabs 100,100 at the first end 40 for the first pair of
legs 30,
19 one tab
on the right and one of the left side of the support beam 20. Similarly
(although not shown), a second pair of tabs 100,100 is provided at the second
end
21 60 for
the second pair of legs 50, one tab on the right and one of the left side of
the
22 support
beam 20. Each leg 80 has an axially-extending recess 110 at an upper end
7
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1 120. Each tab 100 projects downwardly from the support beam 20 and has a
free
2 end 130 for insertion into the axially-extending recess 110 of its
respective leg 80.
3 In an embodiment, the support beam 20 can be a structural beam
4 having lateral sidewalls and at least a web extending longitudinally
therebetween.
As shown, the support beam is a rectilinear hollow tubing having four walls
about a
6 hollow interior, a top wall 140 forming the web or working upper surface,
a bottom
7 web or wall 150 and right and left side walls 160,170. The tabs 100 can
be formed
8 from the right and left side walls 160,170.
9 With reference to Figs. 3A to 3C, one can form the tabs 100 from
the
hollow tubing. As shown in Fig. 3A, facing a side wall, say the right side
wall 160, a
11 first slot 180 can be cut entirely through the right side wall 160 to
the hollow interior,
12 commencing adjacent the top wall 140 and terminating adjacent the bottom
wall 150.
13 As shown in Fig. 3B, a second slot 190 can be cut entirely through the
right side
14 wall 160 to the hollow interior, spaced longitudinally from the first
slot 180 and
commencing again, adjacent the top wall 140 and terminating adjacent the
bottom
16 wall 150. Finally, with reference to Fig. 3C, the first and second slots
180,190 are
17 interconnected to form the free end 130 by removing a portion
longitudinally along
18 the bottom wall 150 between the first and second slots 180,190, the tab
100 only
19 remaining connected to the support beam 20 adjacent the top wall 140. A
leg brace
portion 150F is formed by the remaining bottom wall 150.
21 As shown in Fig. 3D, a tab 100 can be similarly formed on the left
side
22 wall 170, generally opposing the first tab for providing a first pair of
tabs receiving
8
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1 the first pair of legs 30. Further a second pair of tabs can be provided
on the left
2 and rights sides adjacent the second end 60 of the support beam 20 for
receiving
3 the second pair of legs 50.
4 As shown in Fig. 3E, the beam can be a U-shaped channel-shaped
cross-section rotated with the lateral sides 160,170 depending downwardly, the
top
6 wall 140 forming the web. Absent a contiguous bottom wall like the
previous
7 embodiment, a bottom plate 151 is affixed periodically along the
longitudinal beam
8 20 and at each leg location to form a periodic bottom wall and provide a
leg brace
9 portion 150F.
As shown in Figs. 2 and 3C, the upper end 120 of each leg 80 has an
11 axially-extending recess 110, bounded by peripheral walls 220,220. Each
leg 80
12 can also be rectilinear hollow tubing wherein the recess 110 is formed
by the hollow
13 interior and extends the length or height of the leg, although all that
is required for
14 the recess is peripheral walls at the upper end 120. End peripheral
walls 220,220 of
the upper end 120 of the each leg 80 are spaced to correspond with the
longitudinal
16 spacing between the first and second slots 180,190. Further, the first
and second
17 slots 180,190 have a width or kerf 230 sized to accept the wall
thickness of the end
18 peripheral walls 220,220. Further, the lateral peripheral walls 240,240
of the upper
19 end 120 of the each leg 80 provide guides for retaining the leg 80
laterally to the tab
100 and controlling longitudinal rotational movement of the engaged leg 80.
21 The first and second slots 180,190 are parallel so as to receive
22 parallel end peripheral walls 220,220 of leg 80. The upper end 120 of
each leg
9
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1 engages
an upper extent 250 of the kerfs 230 or the top wall 140 of the support
2 beam 20
or combination thereof. Thus, load on the support beam 20 is directed into
3 the leg
80. As shown in one embodiment, the first and second slots 180,190 are
4
substantially vertical and orient the legs 80 perpendicular to the support
beam 20
when viewed from the side. In another embodiment, the parallel first and
second
6 slots
180,190 can be angled to further splay the first pair of legs 30 from the
second
7 pair of legs 50 at an angle from the beam 20.
8 The
width of the kerf 230 is sized about the same as a width of the
9 end
peripheral walls 220 for minimizing angular movement therebetween and
minimizing longitudinal movement of the sawhorse 10 for increasing the
stability
11 thereof.
12 As
shown in Fig. 4, the recess 110 of each leg 80 has a lateral width
13 W or
spacing between lateral peripheral walls 240,240 sufficient to permit angular
14
adjustment of each of the legs 80 when removably connected to its
corresponding
tab 100, enabling adjustment of a lateral spacing therebetween. Each leg 80
can
16 be
removably secured to its corresponding tab 100 by any known locking means.
17 As
shown, and in an embodiment, a bolt or pin 260 can be used to removably
18 secure
a leg 80 to its corresponding tab 100 to avoid loss of the leg 80 if moving
the
19 support
beam 20. The pin 260 can pass through ports 270 formed in each of the
leg's lateral peripheral walls 240,240 and the tab 100. The respective
diameter of
21 the
port 270 and pin 260 can be oversized to avoid accepting much or any of the
22 load
from the support beam 20. One long pin can be used pass through both the
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1 upper ends 120,120 of each leg of the pair of legs 30,50 and respective
tabs
2 100,100. As shown in Fig. 1, a spring clip 280 or other retainer can be
used to
3 retain the pin 270 in position.
4 Referring back to Fig. 1, and to Figs. 5A and 5B the two legs
80,80 of
each of first and second pairs of legs 30,50 are interconnected for
maintaining their
6 relative orientation and providing stability. In an embodiment, the pair
of legs 30 or
7 50 are interconnected to one another by an adjuster 290, such as a
turnbuckle, for
8 manipulating a lateral spacing S between the legs of each pair of legs 30
or 50.
9 Through adjustment of the lateral spacing S between the two legs 80,80 of
a pair of
legs 30 or 50, the height H of the support beam 20 is adjusted above that pair
of
11 legs. Adjustment of the lateral spacing of both pairs of legs can level
or introduce a
12 particular offset or angle along the beam 20.
13 As shown in Fig. 5A, one of the pair of legs 30 or 50 is shown
having
14 been adjusted to a wide lateral spacing Sw for establishing a depressed
height HD
of that first or second end 40,60 of support beam 20. As shown in Fig. 5B, the
pair
16 of legs of Fig. 5A is shown having been adjusted to a narrow lateral
spacing SN for
17 establishing an elevated height HE of the support beam 20. Accordingly,
by
18 adjusting the lateral spacing S between the first pair of legs 30 or
further adjusting
19 the lateral spacing between the second pair of legs 50, the support beam
20 can be
leveled or placed at a particular angle to accommodate a workpiece supported
21 thereon.
11
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1 As shown in Figs. 6A and 6B spacing between the lateral peripheral
2 walls 240,240 of the upper end 120 of the legs 80 and the spacing between
the free
3 end 130 of the tab 100 and the bottom wall 150 assist in limiting angular
rotation of
4 the legs 80 relative to the beam 20 and lateral spacing S of a pair of
legs 30 or 50.
As shown in Fig. 6A, for a wide lateral spacing SW of two legs of the pair of
legs
6 such as that shown in Fig. 5A, the upper end 120 can rotate into the
support beam
7 20. As shown in Fig. 6B, for a narrow lateral spacing SN of two legs of
the pair of
8 legs such as that shown in Fig. 5B, the upper end 120 can rotate away
from the
9 support beam 20, pivoting about a brace portion 150F of bottom wall 150.
With reference to Fig. 5C, for knocking down of the sawhorse 10, the
11 locking means or pins 260 for the first and second pairs of the legs
30,50 can be
12 removed, and the leg recesses 110 withdrawn from their respective tabs
100. The
13 two pairs of legs 30,50, being four independent legs 80,80,80,80, and
the support
14 beam 20 can be laid side-by-side as a compact kit for storage or
shipment. The
adjuster 290, or turnbuckle in this embodiment, is normally connected between
16 respective first and second mount or anchor points 310,320 on each leg
of a pair of
17 legs 30,50. With reference to Figs. 1A,1B and 5C, for storage, one
distal end 300 of
18 the turnbuckle can be disconnected from a first anchor point 310 on one
leg of a
19 pair of legs, pivoted about the second anchor point 320 on the other leg
of the pair
of legs and temporarily reconnected at a third anchor point 330 wholly on the
same
21 leg as the second anchor point 320. In an embodiment, the first, second
and third
22 anchor points 310,320,330 are retaining pins, bolts or the like.
12
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1 In one
example, a heavy duty, knock-down sawhorse can be
2
manufactured using commercially available steel rectilinear hollow tubing. In
an
3
embodiment, a 5 foot long section of 2 inch by 2 inch square tubing, having a
wall
4
thickness of about 1/4 inches, can be used as the support beam. On the first
side
wall (such as the right side wall), at about 6 inches from one of a first or
second end
6 of the
support beam, a first slot of about 1-3/4 inches in length can be cut from
7 about
the extent of the hollow interior at the top wall to about or through the
bottom
8 wall. A
second slot of about 1-3/4 inches in length is cut, spaced longitudinally from
9 the
first slot and parallel thereto. The bottom wall between the first and second
slots is removed by at least the thickness of the bottom wall to expose the
end 130
11 of the tab 110.
12 Each
leg can be a 31 inch long section of 2 inch by 1 inch square
13 tubing,
having a wall thickness of about 1/8 inches. Accordingly, the first and
14 second
slots have a kerf width of about 1/8 or slightly wider for tolerance
considerations, corresponding to the wall thickness of the end peripheral
walls of a
16 leg.
The first and second slots are longitudinally spaced, from their longitudinal
17
extents, about 2" corresponding to the longitudinal spacing of end peripheral
walls
18 220,220 of the leg.
19 The
first and second slots 180,190 can be interconnected by removal
of a longitudinal portion of the bottom wall to form a tab about 1-% inches
wide and
21
downwardly depending from the top wall. The interconnection of the first and
22 second
slots to free the tab end 130 can be by recessing a portion of an edge of the
13
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1 bottom wall, the portion of the edge being defined by the bottom wall and
the first
2 side wall and being between the first and second slots. The bottom wall
is recessed
3 by about the tab thickness, being the wall thickness, and a further amount
4 corresponding about to the wall thickness of the upper end of the leg.
Accordingly,
when connected, the legs can be rotated angularly and substantially
vertically.
6 Three more tabs can be cut from the first and second lateral side walls
in similar
7 fashion for forming a total of at least four tabs, a pair of tabs at each
of the first and
8 second ends of the support beam.
9 Applicant notes that the tolerances for all of the cuts in the
formation
of the tabs are about 1/500 inches. Such tolerances provides for a snug or
tight
11 fitment of the legs over the tabs and which limits longitudinal movement
of the
12 sawhorse.
13 Each of the four sections of rectangular tubing can be fit about
each of
14 the four tabs of the horizontal beam such that the upper end recess 110
of each leg
engages a top of the slot or kerf or engages the top wall 140. Each pair of
legs
16 30,50 is secured to the support beam 20 by a pin.
17 For each pair of legs, a concentric port is drilled through each
leg as
18 well as through their corresponding tabs. A single pin sufficiently long
enough to
19 pass through both supporting legs and the width of the horizontal beam
is then
inserted through the concentric port. The pin can be secured in position by a
simple
21 retaining clip.
14
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1 Finally, a turnbuckle is attached to interconnect the legs of
each pair
2 of legs, for adjusting a lateral spacing between the two legs. The
turnbuckle can be
3 attached at about 20 inches from the upper end of the legs.
4 Applicant has found that this particular embodiment enables the
working height be adjustable vertically by about one inch at each end 40,60.
This
6 enables the sawhorse to have a maximum slope of about 2 inches.
Accordingly,
7 this particular embodiment can be adjusted to provide a level work
surface on
8 ground surfaces that have a slope of no greater than about 2 inches.
9
