U.S. patent number 3,911,511 [Application Number 05/528,018] was granted by the patent office on 1975-10-14 for spring assembly.
This patent grant is currently assigned to Leggett & Platt, Incorporated. Invention is credited to Larry Higgins, Henry Zapletal.
United States Patent |
3,911,511 |
Higgins , et al. |
October 14, 1975 |
Spring assembly
Abstract
A spring assembly for mattresses, innersprings, and the like.
The assembly comprises rows of coils, each row comprising a
continuous length of wire formed into a plurality of like-handed
coils interconnected by Z-shaped wire segments alternately disposed
at the top and bottom of the coils. Adjacent rows of coils are of
the same hand or twist and are coupled by a helical wire wound
through overlapping Z-shaped wire segments.
Inventors: |
Higgins; Larry (Carthage,
MO), Zapletal; Henry (Carthage, MO) |
Assignee: |
Leggett & Platt,
Incorporated (Carthage, MO)
|
Family
ID: |
24103923 |
Appl.
No.: |
05/528,018 |
Filed: |
November 29, 1974 |
Current U.S.
Class: |
5/255; 5/267;
5/721 |
Current CPC
Class: |
A47C
27/065 (20130101); A47C 27/07 (20130101); A47C
27/068 (20130101) |
Current International
Class: |
A47C
27/04 (20060101); A47C 27/07 (20060101); A47C
27/06 (20060101); A47C 023/04 (); A47C
025/00 () |
Field of
Search: |
;5/246,260,266-269,271,351 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nunberg; Casmir A.
Attorney, Agent or Firm: Wood, Herron & Evans
Claims
Having described our invention, we claim:
1. A spring assembly comprising,
a plurality of rows of coils, each of said rows of coils being
formed from a continuous length of wire, segments of wire
interconnecting adjacent coils in each of said rows, said segments
each being substantially Z-shaped and disposed alternately in first
and second planes generally perpendicular to the axis of said coils
at the ends thereof, portions of said Z-shaped segments extending
beyond the periphery of said coils, said Z-shaped interconnecting
segments each generally defining a rectangle of width greater than
the maximum diameter of said coils, adjacent coils within each of
said rows being situated at diagonally opposite corners of said
rectangles, the axes of coils in each of said rows thereby being
disposed alternately in two offset parallel planes,
sections of each of said Z-shaped interconnecting segments of each
row being overlapped relative to Z-shaped interconnecting segments
of adjacent rows,
helical spring means extending parallel to said rows for the length
of said rows, said helical spring means being wound through said
overlapped sections of said Z-shaped interconnecting segments so as
to secure said rows of coils in an assembled relation, and
said overlapped sections of said Z-shaped interconnecting segments
being radiused, the radii of said overlapping sections being
substantially greater than the radius of said helical wire so that
said helical wire permits relative pivotal movement between said
overlapped sections of said Z-shaped interconnecting segments of
said rows but precludes all other relative movement.
2. The spring assembly as defined in claim 1 wherein the coils
within each row are like-handed and the coils in adjacent rows are
also like-handed.
3. The spring assembly of claim 1 in which said radius of said
overlapped sections of said Z-shaped interconnecting segments is
approximately eight times the radius of said helical wire.
4. A spring assembly comprising
a plurality of rows of coils, each of said rows being formed from a
single continuous piece of wire and each of said rows containing a
plurality of coils interconnected by Z-shaped interconnecting
segments, alternate ones of said Z-shaped interconnecting segments
being disposed in the planes of the upper and lower surfaces of
said spring assembly, the axes of alternate ones of said coils in
one of said rows being disposed in a first plane perpendicular to
the upper and lower surfaces of said spring assembly, the axes of
the other coils in said row being substantially parallel and
disposed in a second plane parallel to, but displaced from said
first plane,
sections of each of said Z-shaped interconnecting segments of each
row being overlapped relative to Z-shaped interconnecting segments
of an adjacent row,
helical spring means extending parallel to said rows for the length
of said rows, said helical spring means being wound through said
overlapped sections of said Z-shaped interconnecting segments so as
to secure said rows of coils in an assembled relation, and
said overlapped sections of said Z-shaped interconnecting segments
being radiused, the radii of said overlapping sections being
substantially greater than the radius of said helical wire so that
said helical wire permits relative pivotal movement between said
overlapped sections of said Z-shaped interconnecting segments of
said rows but precludes all other relative movement.
5. The spring assembly of claim 4 in which said overlapped sections
of said Z-shaped interconnecting segments are radiused, the radii
of said overlapping sections being substantially greater than the
radius of said helical wire so that said helical wire permits
relative pivotal movement between said overlapped sections of said
Z-shaped interconnecting segments of said rows but precludes all
other relative movement.
6. The spring assembly of claim 4 in which said radius of said
overlapped sections of said Z-shaped interconnecting segments is
approximately eight times the radius of said helical wire.
7. A spring assembly comprising,
a plurality of rows of coils, each of said rows of coils being
formed from a continuous length of wire, segments of wire
interconnecting adjacent coils in each of said rows, said segments
each being substantially Z-shaped and disposed alternately in first
and second planes generally perpendicular to the axis of said coils
at the ends thereof, portions of said Z-shaped segments extending
beyond the periphery of said coils,
sections of each of said Z-shaped interconnecting segments of each
row being overlapped relative to Z-shaped interconnecting segments
of adjacent rows,
helical spring means extending parallel to said rows for the length
of said rows, said helical spring means being wound through said
overlapped sections of said Z-shaped interconnecting segments so as
to secure said rows of coils in an assembled relation, and
said overlapped sections of said Z-shaped interconnecting segments
being radiused, the radii of said overlapping sections being
substantially greater than the radius of said helical wire so that
said helical wire permits relative pivotal movement between said
overlapped sections of said Z-shaped interconnecting segments of
said rows but precludes all other relative movement.
8. The spring assembly of claim 7 in which said Z-shaped
interconnecting segments each generally define a rectangle of width
greater than the maximum diameter of said coils,
the coils within each row being like-handed and the coils in
adjacent rows also being like-handed.
9. The spring assembly as defined in claim 7 wherein the coils
within each row are like-handed and the coils in adjacent rows are
also like-handed.
10. The spring assembly of claim 7 in which said radius of said
overlapped sections of said Z-shaped interconnecting segments is
approximately eight times the radius of said helical wire.
11. A spring assembly comprising
a plurality of rows of coils, each of said rows being formed from a
single continuous piece of wire and each of said rows containing a
plurality of coils interconnected by Z-shaped interconnecting
segments, alternate ones of said Z-shaped interconnecting segments
being disposed in the planes of the upper and lower surfaces of
said spring assembly, the axes of said coils being disposed
perpendicular to the upper and lower surfaces of said spring
assembly,
sections of each of said Z-shaped interconnecting segments of each
row being overlapped relative to Z-shaped interconnecting segments
of an adjacent row,
helical spring means extending parallel to said rows for the length
of said rows, said helical spring means being wound through said
overlapped sections of said Z-shaped interconnecting segments so as
to secure said rows of coils in an assembled relation, and
said overlapped sections of said Z-shaped interconnecting segments
being radiused, the radii of said overlapping sections being
substantially greater than the radius of said helical wire so that
said helical wire permits relative pivotal movement between said
overlapped sections of said Z-shaped interconnecting segments of
said rows but precludes all other relative movement.
12. The spring assembly as defined in claim 11 wherein the coils
within each row are like-handed and the coils in adjacent rows are
also like-handed.
13. The spring assembly of claim 11 in which said radius of said
overlapped sections of said Z-shaped interconnecting segments is
approximately eight times the radius of said helical wire.
Description
The present invention relates to spring assemblies of the type
commonly used in the construction of innersprings, mattresses,
upholstered furniture, and the like. More particularly, the present
invention relates to a mattress spring core assembly in which each
of the rows of coils is formed from a single continuous length of
wire.
The prior art is replete with spring assemblies useful for
mattresses, innersprings, and the like. While these are of various
configurations, most of them employ rows of coils interconnected at
the top and bottom by wire lacings. Such prior art spring
assemblies, varied though they are in exact configuration, all are
subject to some shortcomings. Primary among these shortcomings is
the large amount of wire employed to make up the coil, as well as
the complexity of the lacing schemes employed for the
interconnection of the coils. Many of the configurations are
subject to the requirement that they be hand assembled and
consequently they are excessively expensive to manufacture.
Another typical problem in the manufacture of mattresses or
innersprings is that of optimizing comfort by utilizing coil
assemblies which are relatively firm yet resilient, with a minimum
of lateral deflection, or so-called "water bed" effect. Optimally,
when a person is lying on a mattress, the coils beneath him give
sufficiently to accommodate the contour of the body but not so much
so that proper orthopedic support of the body is lost. Moreover,
the coils to either side of the person should be deflected by a
minimal amount and help to carry the weight on the primary loaded
spring coils. Then, too, the mattress or innerspring should be
quiet, i.e., free from noise caused by scraping or slapping of
adjacent coils or interconnections when deflected by the weight of
a person sitting or reclining on the spring assembly.
One approach to overcoming the problems and shortcomings set forth
hereinabove is disclosed in U.S. Pat. No. 3,657,749 in which rows
of coils are formed from a continuous length of wire interconnected
by Z-shaped connecting segments. The opposite rows of coils are of
opposite hands, i.e., of alternately right hand and left hand
twist, and the rows are interconnected by a zigzag connector wire.
The primary advantage of the spring assembly disclosed in this
patent is that it facilitates machine construction of the springs
without any manual assistance and it substantially reduces the
quantity of wire required to obtain a given degree of firmness.
While the spring core assembly disclosed in U.S. Pat. No. 3,657,749
has the advantages set forth hereinabove, it also suffers from
several shortcomings. Specifically, that assembly has been found to
be very noisy in that it allows wires to snap over each other and
to come into contact with other wires during compression and
relaxation of the individual spring coils. Additionally, there is a
problem of the invididual coils shifting laterally in the course of
compressing with the result that the complete assembly has the feel
of a water bed, i.e., it allows the top surface to move laterally
as well as to deflect in the course of compression.
Another problem or shortcoming encountered with the spring assembly
disclosed in U.S. Pat. No. 3,657,749 is that it is possible when a
corner is deflected severely as mattresses often are in the course
of placing a fitted sheet over the mattress, for the coils to
become overlapped and locked in that overlapped condition. When
that overlapping occurs the mattress either has a "hole" or
unsupported area in it, or it is maintained in a deflected or bent
condition.
The shortcomings of U.S. Pat. No. 3,657,749 have been overcome by
this invention without sacrificing the advantages of their
construction. According to the practice of this invention, a row of
coils are all made of a single continuous strand of wire and all of
the rows are of the same hand or twist. These rows are placed in
juxtaposition with the Z-shaped interconnecting segments of
adjacent rows in overlapping relation and the overlapping sections
of the Z-shaped segments are laced or secured together by a helical
wire connector.
This construction has numerous advantages over that of the above
identified patent while it still retains the advantages of the
spring assembly of U.S. Pat. No. 3,657,749. Specifically, it
maintains the advantages of being capable of being manufactured and
assembled without any hand labor and it maintains the advantage of
being capable of being manufactured of lightweight, inexpensive
wire so that material cost is substantially reduced. Additionally,
though, it overcomes the shortcomings of the mattress assembly
disclosed in the above identified patent by eliminating the noise
and the lateral shifting problem. It also is so constructed that it
is impossible for the individual coils to become overlapped and
interlocked.
Another advantage of the spring core assembly of this invention is
that it is easily adaptable to the manufacture of varying size
mattresses because the length may be varied without varying the
width and vice versa. In the mattress core assemblies of the above
identified patent, the variation in one dimension, i.e., length,
required a corresponding change in the other direction, i.e.,
width. With the construction of this invention, either may be
varied without affecting the other.
These and other advantages of this invention will be more readily
apparent from the following description of the drawings, in
which:
FIG. 1 is a perspective view of a corner of an innerspring
embodying the invention of this application.
FIG. 2 is a top plan view of the innerspring of FIG. 1.
FIG. 3 is an end elevational view taken on line 3--3 of FIG. 2.
FIG. 4 is an end elevational view taken on line 4--4 of FIG. 2.
FIG. 5 is a diagrammatic plan view in which each coil pair in each
row is designated by block lines constituting continuations of the
Z-shaped coil interconnection segments.
FIG. 6 is a top plan view of a second embodiment of the invention
of this application.
FIG. 7 is a diagrammatic plan view of the embodiment of FIG. 6 in
which each coil pair in each row is designated by block lines
constituting continuations of the Z-shaped coil interconnection
segments.
Referring now to the drawings and particularly to FIGS. 1 and 2,
there is shown an innerspring unit 20 utilizing a spring assembly
made in accordance with the invention of this application. The
upper surface 21 of innerspring 20 has a generally rectangular
periphery 22 which may be enclosed by a border wire (not shown).
Similarly, the lower surface 23 of innerspring 20 has a rectangular
periphery which also may be enclosed by a border wire (not
shown).
Innerspring 20 includes a plurality of rows 24, 25, 26 of coils,
all of the same twist, as, for example, all right handed twist or
all left handed twist. As best illustrated in FIGS. 1 and 2, each
row 24, 25, and 26 of coils is formed from a continuous length of
wire. The wire is wound to form a plurality of spaced coil pairs 27
interconnected by substantially Z-shaped wire segments 28, 18
disposed sequentially first in the plane of upper innerspring
surface 21 and then within the plane of lower innerspring surface
23.
As best illustrated in FIG. 2, each coil pair 27 comprises a first
right handed coil 27a offset from a second right handed coil 27b,
having the same number of turns as coil 27a. As seen in FIG. 5, the
axes of coils 27a lie within a plane 29 which is parallel to, but
spaced apart from, a second plane 30 within which lie the axes of
offset coils 27b. It will be appreciated from FIG. 2 that the axes
of adjacent coils 27a and adjacent coils 27b are equidistant, the
axes being generally perpendicular to the upper and lower surfaces
21 and 23 of innersrping unit 20.
While each of the coils 27a and 27b is illustrated as having
approximately two full turns or revolutions, this number is not
critical. Thus, a greater or lesser number of convolutions may be
used, depending upon the tensile strength of the wire and the
manner in which the coils are formed so as to provide a spring
force appropriate to the particular application.
As will be appreciated from the following description, the coil
interconnection technique utilized in innerspring mattress 20
prevents adjacent coils from binding when compressed even though
they are not of hourglass configuration. Thus, a variety of shapes
may be employed such as hourglass or potbellied, but the
cylindrical shape illustrated is perferred.
Each row 24, 25, and 26 is configured identical to each adjacent
row and each coil within each row 24, 25, 26 is identical to every
other coil and of the same twist or hand.
In the preferred embodiment of the invention, the spacing between
axes of adjacent coils within row 24 is the same as between axes
spacing of adjacent coils and rows 25 and 26. Further, should a
coil pair in row 24 be interconnected in the plane of upper
innerspring surface 21, the adjacent coil pair in row 25 is
interconnected in the same plane of upper innerspring surface 21.
This is best illustrated in FIGS. 1 and 2 where in row 24, typical
adjacent coils 27a, 27b are interconnected by Z-shaped wire segment
28 lying within upper innerspring surface 21. The adjacent coil
pair 32 in row 25, coils 31a and 31b, are interconnected by a
Z-shaped wire segment 32 lying in the same plane of the upper
innerspring surface 21 and Z-shaped wire segment 33 lying in the
same plane of the lower surface 23. This pattern is repeated
throughout the innerspring unit 20. The result is Z-shaped segments
in the plane of the upper surface 21 are aligned in columnar
fashion and similarly the Z-shaped segments in the plane of the
lower surface 23 are also aligned in columnar fashion in vertical
planes which are located midway between the vertical plane of the
Z-shaped segments in the plane of the upper surface 21. Otherwise
expressed, the Z-shaped segments which interconnect the pairs of
coils are aligned both in rows and in columns in the planes of the
upper and lower surfaces 21 and 23.
In order to connect the adjacent rows of coils, the Z-shaped
segments which interconnect adjacent pairs of coils within each row
are positioned so that they overlap the Z-shaped segments of the
adjacent row of coils. These overlapped portions or sections of the
Z-shaped segments are then tied together by helical wire
connectors. A first set of helical wire connectors, herein
designated 34, is disposed within the plane of upper innerspring
surface 21 so as to join together overlapped portions 35 of upper
Z-shaped interconnection segments 28, 32. Similarly, a second set
of helical wire connectors, herein designated 36, lie within the
plane of lower innerspring surface 23 and serve to join together
overlapped portions 37 of lower Z-shaped interconnection segments
18 and 33. As evident in the plan view of FIG. 2, the length of
each helical wire is the same as the length of the rows, and the
helical wires 34, 36 extend parallel to the rows.
The assembly of the helical wires to the row of continuous coils
may be easily accomplished on a completely automatic assembly
machine. In such a machine, the adjacent rows of coils are
positioned so that the sections 35 and 37 of the adjacent Z-shaped
segments are positioned in overlapping relationship and a helical
wire is then rotated or screwed onto the overlapping portions of
the Z-shaped segments. After completion of the threading of the
helical coil onto the Z-shaped segments, the helical coil is cut to
length so that the now-connected adjacent rows of coils may be
indexed forwardly and another pair of upper and lower helical wires
threaded over the next row of coils. This process is repeated for
the desired length of the mattress, after which the spring assembly
is removed from the machine.
Referring now to FIG. 2, it will be seen that the diameters of the
helical wires 34 and 36 are approximately one-fourth the radius of
the overlapped portions 35 and 37 of the Z-shaped segments. This
relationship of having the radius of the Z-shaped segments over
which the helical wire is threaded approximately eight times the
radius of the helical wire has the effect of permitting two
rotations of the helical wire to pass through and lock adjacent
overlapped segments together. So locked or interconnected, the
adjacent coils are free to pivot relative to each other but are
locked against relative longitudinal or lateral movement. In other
words, this relatively small diameter helical coil when used to
lock the overlapped large radiused sections of the segments
together, permits only relative pivotal movement between the
adjacent interconnected coils.
Referring now to FIG. 5, each block 50 represents the outline of a
typical upper Z-shaped interconnection segment 28 in coil row 24.
Similarly, each block 52 represents the outline of a typical upper
Z-shaped interconnection segment 32 in coil row 25. Each block 60
represents the outline of typical lower Z-shaped interconnection
segment 18 in coil row 24 and each block 61 represents the outline
of a typical lower Z-shaped interconnection segment 33 in coil row
25. As is apparent from the diagram in FIG. 5, the blocks 50, 52,
and 60, 61 represent load supporting units. Each of these units 50,
52 and 60, 61 are overlapped so that the effect of the construction
of coil assembly is one of a very densely packed innerspring
assembly with a very high count of coils. This construction enables
a very small gage wire to be utilized in the innerspring. It is a
particularly advantageous structure for use in a foamed in spring
mattress such as the spring mattress disclosed in U.S. Pat. No.
3,660,876.
Referring to FIG. 6, there is illustrated a second embodiment of
the invention of this application. This construction is illustrated
diagrammatically in top plan view in FIG. 7.
In general, the spring assembly of FIGS. 6 and 7 is identical to
the spring assembly of FIGS. 1-5, except that the rows of coils are
positioned within the interconnecting Z-shaped segments so that the
vertical axes of all of the coils of a single row are located in
the same vertical plane 130, rather than being alternately
staggered in two different planes as in the embodiment in FIGS.
1-5. The Z-shaped segments, rather than extending outwardly from
one side only of each coil extend outwardly beyond both sides of
each coil so that this construction has the same advantages of the
embodiment of FIGS. 1-5 in that it minimizes or eliminates any
tendency of the coils to overlap or contact adjacent convolutions
of the same coil. Specifically, referring to FIG. 5, it will be
seen that in this embodiment each row of coils 124, 125, 126 is
formed from a continuous length of wire and each wire is wound to
form a plurality of spaced coil pairs 127 interconnected by
substantially Z-shaped wire segments 128 disposed in the plane of
upper innerspring surface 121. The substantially Z-shaped wire
segments 118 interconnect adjacent coil pairs 127 within the plane
of lower innerspring surface 123.
In this embodiment each coil pair 127 comprises a first right
handed coil 127a offset from a second right hand coil 127b having
the same number of turns as coil 127a. In this embodiment though
the axes of coils 127a lie within the same plane 130 within which
lie the axes of coils 127b. In this embodiment as in the embodiment
of FIGS 1-5, each row 124, 125, 126 is configured identically to
each adjacent row and each coil within each row is of the same
twist or hand.
In this embodiment, the corners of the interconnecting Z-shaped
segments are both located outwardly from the circumference of the
coils 127a and 127b within each pair of coils in both the planes of
the upper and lower surfaces of the mattress. This outward spacing
of the Z-shaped segments facilitates interconnection of the
overlapped portions of Z-shaped segments by the helical springs
134.
The primary advantage of both embodiments of the spring assembly
described herein is that they both utilize continuous springs which
extend for the length of each row of coils and because of this
continuous row construction, the assembly may be easily machine
manufactured and assembled. This construction also has the
advantage of eliminating the knots conventionally formed in each
coil. Additionally, this construction has the advantage of
facilitating the manufacture of a very firm mattress or innerspring
unit from a very thin gage wire and a gage which is much thinner
than any which has heretofore been acceptable for manufacture of
innerspring units. Additionally, the invention of this application
eliminates side sway of "water bed" effect. It also eliminates
noise problems encountered when adjacent coils move relative to
each other or snap past each other in the course of flexure of the
unit assembly.
While we have described only two embodiments of our invention,
persons skilled in the arts to which this invention pertains will
appreciate other changes and modifications which may be made
without departing from the spirit of our invention. Therefore, we
do not intend to be limited except by the scope of the following
appended claims.
* * * * *