U.S. patent number 3,805,712 [Application Number 04/799,213] was granted by the patent office on 1974-04-23 for weight responsive table.
This patent grant is currently assigned to SAID Taylor, by said Grantham. Invention is credited to Frederick W. Grantham, David J. Taylor.
United States Patent |
3,805,712 |
Taylor , et al. |
April 23, 1974 |
WEIGHT RESPONSIVE TABLE
Abstract
A table with a top that automatically lowers when a load on the
table is heavy and automatically raises when the weight of the load
is light. The table has pivoted supports between the top and a base
of the table and these pivoted supports are pivotally joined to
interconnecting leveling means. A series of springs connected to
the supports engage at different heights of the top and smoothly
urge the top upwardly from the base.
Inventors: |
Taylor; David J. (Glendale,
CA), Grantham; Frederick W. (Los Angeles, CA) |
Assignee: |
SAID Taylor, by said Grantham
(N/A)
|
Family
ID: |
25175315 |
Appl.
No.: |
04/799,213 |
Filed: |
February 14, 1969 |
Current U.S.
Class: |
108/136; 108/145;
248/573; 5/56; 248/421; 248/642 |
Current CPC
Class: |
A47B
9/02 (20130101) |
Current International
Class: |
A47B
9/00 (20060101); A47B 9/02 (20060101); A47b
009/02 () |
Field of
Search: |
;108/136,145,149,87,77,114 ;248/399,401,421,277 ;5/56,8,63
;312/71,319 ;298/399 ;16/128 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
9,386 |
|
Mar 1906 |
|
DK |
|
999,010 |
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Jul 1965 |
|
GB |
|
Primary Examiner: Gay; Bobby R.
Assistant Examiner: Aschenbrenner; Peter A.
Attorney, Agent or Firm: Barger; Larry N.
Claims
We claim:
1. A table having ends comprising: a base; a top; a pair of spaced
apart supports, each having ends pivotally connected to the top and
base adjacent ends of the table, with an intermediate pivot joint
in each support between its ends; spring means connected to the
table which upwardly biases the top so that the top moves up as its
load decreases and down as its load increases, which spring means
has a plurality of springs, each engagable at different vertical
heights of the top to insure a smooth vertical movement of the top
as it raises and lowers in response to the amount of weight carried
by the top; a leveling and vertical movement stabilization system
including a pair of crossed coupler members, one coupler member
having end portions pivotally connected to the intermediate joints
of the supports, and the other coupler member having one end
portion pivotally connected to the table adjacent one end of the
table above the intermediate joint of one support and an opposite
end portion pivotally connected to the table adjacent an opposite
end of the table below the intermediate joint of the other
support.
2. A table having ends comprising: a base; a top positioned above
the base; said table having four quadrants of approximately equal
size defined by a longitudinal vertical axial plane and an
intersecting lateral vertical axial plane; a support in each
quadrant, each support having ends pivotally connected to the top
and base adjacent ends of the table, with an intermediate pivot
joint in each support between its ends; a hitching member extending
across the longitudinal vertical axial plane, which hitching member
is joined to the two supports that are on the same side of the
lateral vertical axial plane; a spring under tension joined to the
base and to the hitching member and upwardly biasing the top so
that the top moves up as its load decreases and down as its load
increases; a leveling and vertical movement stabilization system
including a pair of crossed coupler members, one coupler member
having end portions pivotally connected to the intermediate joints
of two of the supports, and the other coupler member having one end
portion pivotally connected to the table adjacent one end of the
table above the intermediate joint of one support and an opposite
end portion pivotally connected to the table adjacent an opposite
end of the table below the intermediate joint of another
support.
3. A table as set forth in claim 2, wherein the hitching member is
generally U-shaped with a back and two legs, said legs forming an
acute angle with the supports and being joined to the supports
below their intermediate pivot joints, whereby the spring under
tension has a lever advantage to pull the table upwardly from the
top's lowest position.
4. A table as set forth in claim 2, wherein the two supports on an
opposite side of the lateral vertical axial plane also are
connected together by a second hitching member extending across the
longitudinal vertical axial plane, and there is a second spring
under tension joined to the base and to said second hitching
member.
5. A table as set forth in claim 2, wherein there are a plurality
of springs connected between the base and hitching member, each
spring being engagable at a different vertical height of the top to
insure a smooth vertical movement of the top as it raises and
lowers in response to changes in the amount of weight carried by
the top.
Description
This invention relates to a table having a height that is
responsive to the weight of the load carried by the top of the
table. The top lowers when the load is heavy and raises when the
load is light to keep the upper portion of the load within easy
reach of persons loading or unloading the table. This table is
useful to support many different types of stacked articles, such as
canned foods, crates of industrial parts, library books, piles of
laundry, etc.
One particularly useful adaptation of the table is in the
commercial laundry field. If one can visualize the familiar sight
of a pile of laundry for a family of four or five piled on a
sorting table, one can readily comprehend the very large laundry
piles of perhaps 250 sheets or more that are created in the laundry
rooms of hotels, motels hospitals, etc. Such large piles of laundry
make it difficult for workers to feed the laundry into ironing
machines after the laundry has been washed. The ironing machines
have an input section that is at a fixed height of about three feet
above the floor of the laundry room. Attempts to use shorter tables
so the upper portion of the laundry pile was more easily accessible
created additional problems, because workers feeding the ironing
machine had to stoop to get the last piece of laundry from the
table and then lift it up to the input section of the ironer. For
decades there has been a problem with feeding large piles of
laundry into an ironing machine.
We have overcome this problem by providing a table which is simple
in construction and which has a top that lowers when the load on
the table is heavy and which raises as portions of the load are
removed. Thus, the uppermost article of the load can always be
easily reached by the persons loading or unloading the table.
The table of this invention has pivoted supports between a base and
a top of the table and the supports are spring biased by a
plurality of springs engagable at different heights of the top to
urge the top upwardly and smoothly raise the top as portions of the
load are removed. The table also has a leveling member pivotally
connected to the supports to hold the top horizontal and keep the
top from wobbling as it raises and lowers.
Perhaps the invention can be better understood with reference to
the attached drawings, in which:
FIG. 1 is a perspective view of the table showing the table in
raised position;
FIG. 2 is a side elevational view of the table in raised
position;
FIG. 3 is a left end elevational view of the table in raised
position;
FIG. 4 is an enlarged left end elevational view of the table shown
fully loaded with laundry with the table top in a lowered position,
which table is shown next to a flatwork ironing machine;
FIG. 5 is an enlarged left end elevational view of the table
similar to FIG. 4, but showing the table nearly unloaded with the
top in a higher position;
FIG. 6 is a fragmentary perspective view of the lower left end
portion of the table, with the perspective view taken from a rear
of FIG. 1 to clearly show the springing structure that urges the
table's top upwardly; and
FIG. 7 is an enlarged fragmentary side elevational view taken from
the rear of FIG. 2 showing the left half of the table in FIG.
2.
Referring in detail to these drawings, the table includes a base 1
and a top 2 positioned above the base. The base is preferably
formed of two low profile A-frame members 3 and 4 joined to lateral
cross bars. As shown in FIGS. 2 and 3, the table is divided into
four quadrants by a longitudinal vertical axial plane 5 and an
intersecting lateral vertical axial plane 6. To support the top 2
above base 1, each quadrant of the table has a support designated
respectively as 7, 8, 9 and 10. Supports 7 and 10 have their upper
ends pivotally connected at fixed locations to the top at 11 and 12
and have their lower ends pivotally connected at fixed locations to
the base at 13 and 14. Between the upper and lower ends of supports
7 and 10 are intermediate pivot joints 15 and 16. The supports 8
and 9 are likewise pivotally joined at their upper and lower ends
to fixed locations of the top and base and have intermediate pivot
joints at 17 and 18.
To keep the table top 2 in a predetermined attitude as the top
raises and lowers, there are rigid elongated couplers 19 and 20
extending across the lateral vertical axial plane 6 and these
couplers are connected at their ends to the intermediate pivot
joints of the supports. Thus, the supports all bend in the same
direction; for example, to the right in FIG. 1. Preferably, the top
is level and parallel to the base and moves up and down in a
rectilinear motion perpendicular to the base. Working in
conjunction with these rigid couplers 19 and 20 are two leveling
bars 21 and 22 which are very important features of this invention.
In FIG. 1, taking leveling bar 21 as illustrative, the leveling bar
21 has one end pivotally connected at 23 to support 7 above its
intermediate pivot joint and has its opposite end pivotally
connected at 23a to opposite support 10 below its intermediate
joint. The leveling bar 22 is likewise connected to opposite
supports 8 and 9.
The table of this invention is responsive to the amount of weight
supported on top 2 of the table. As best shown in FIGS. 1 and 2,
the pivoted supports have springs connected between the base 1 and
a hitching member 24, which is in turn connected to the supports 7
and 8. The tension springs indicated at 25 pull at the portions of
the supports below the intermediate pivot joints 15 and 17 and urge
the supports toward a more straightened position to raise the table
top. The uppermost limit to which the top can raise before the
tension springs completely relax is adjustable by varying the
length of a link chain 26 having one end joined to a cross bar 27
between the intermediate pivot joints of the supports and having
the other end joined to a cross bar 28 of the base.
When the table raises and lowers in response to the load, the table
operates as illustrated in the rear perspective view of FIG. 6. The
supports 7 and 8 have sections below their intermediate pivot
joints 15 and 17 joined to legs of the U-shaped hitching member 24,
which legs are preferably at an angle, such as 45.degree., to the
supports below their intermediate pivot joints. This relationship
between the hitching member and the supports allows the top of the
table to sink when fully loaded to less than one-half of its
tallest height without the top hitting the hitching member 24. A
sample table made in accordance with this invention exhibited a
vertical range between 15 inches and 33 inches above the floor at
its respective lower and upper limits. This is because the upper
portion of the hitching member arcs downwardly after the legs of
the hitching member passes a vertical position as the lower
sections of supports 7 and 8 pivot to the left in FIG. 6. However,
when the table is at its lowest position, the hitching member still
provides a lever advantage with springs 29 connected to a back of
the U-shaped hitching member 24 pulling the supports toward a more
vertical position to raise the top as the table is unloaded.
Still referring to FIG. 6, the spring structure is a very important
feature of this invention. We found in working with
weight-responsive tables that one or even two springs engaging at
the same time and having approximately the same stretch
characteristics caused the table to move up and down erratically.
Sometimes, when the load was increased a small amount, the top
would suddenly sink a considerable distance. Conversely, the top
would jerk upwardly suddenly as a small segment of the load was
removed.
We have overcome this problem of erratic movement by providing a
series of springs that engage at different height positions of the
top. We call this spring structure "compound springing." These
springs can be adjusted to vary the particular height at which they
engage by adjusting the length of link chains 29 connecting the
springs to the table. In FIG. 6, five springs are shown, but there
could be more springs or less springs. Also, the same type of
"compound springing" and hitching member can be used on supports 9
and 10. We have discovered that the "compound springing" gives a
smooth action to the table as it moves between its upper and lower
limits.
The operation of the table is probably best illustrated in FIGS. 4
and 5 where the table is moved adjacent a commercial ironing
machine 30 shown here in a fragmentary schematic drawing. The table
has rollers 33 and 34 to make it easy to roll the table up to the
ironing machine. The ironing machine has a moving belt 31 onto
which articles of laundry, such as sheets, are fed into the ironer.
The sheets are then moved between padded rollers and steam chambers
to smooth and iron the sheets. In FIG. 4, the table is loaded with
a full load of approximately 250 sheets and the table has
automatically lowered to a position where it is easy to pull sheets
off the top of the laundry pile. In FIG. 5, the table is nearly
unloaded and the "compound springing" mentioned above has moved the
table top upwardly to where it is easy to grasp the last few sheets
and feed them into the ironing machine. When the table is used for
wide piles of laundry, for instance sheets, a hinged flap 32 of the
table can be raised to increase the size of the top. This flap 32
can be lowered, as shown in dotted lines, when smaller articles,
such as pillow cases, are piled on the table. When the flap 32 is
down, the table with small articles can be rolled more closely to
the ironer 30.
In the preceding specification, the table of this invention has
been described as used in a commercial laundry by way of example.
However, the table can be designed for many other uses. Also, only
one embodiment of the table has been shown. It is understood that
persons skilled in the art will know how to make certain
modifications to this invention without departing from the spirit
and scope of the invention.
* * * * *