[0001] This Patent of invention refers to a bedstead formed by a succession of transversal
springs fitted on a frame structure. Apart from others which we shall be seeing later,
this bedstead offers the special feature of its springs being made from fibre reinforced
plastic materials.
[0002] Amongst the highly varied types of bedstead, those in which the functional area is
formed by a series of wooden springs provided with extraordinary qualities of strength
and flexibility are known in the marketplace. They offer optimum adaptation for supporting
the mattress and, consequently, the person using the bed. This is why these bedsteads
are so widely used, so much so that it may be stated with no doubt at all that, at
the present time, they are the ideal mattress base most accepted both by users and
merchants, in the manufacturing industry and even by health authorities.
[0003] The excellency of the aforementioned wooden spring bedsteads is grounded, as we have
said, on the qualities of the springs' strength and flexibility but it is precisely
these points where the problems and disadvantages that these products suffer from
lie.
[0004] In fact, for springs to act as such, it is necessary to follow a laborious manufacturing
process since they are made up of a package of thin wooden strips, duly compacted
and given a slight arching effect. With wood being their basic, main component, it
is easy to understand that the springs are significantly affected by weather conditions
such as environmental humidity, temperatures, etc., despite the fact that, in better
quality bedsteads, these springs are given a plastic protection which, apart from
contributing towards raising the price of the product, also has the disadvantage of
breaking because of friction or other unforeseeable causes, thus leaving the springs'
wooden component uncovered. They would then unfailingly deteriorate in their functionality
as time elapses.
[0005] On the basis of the prestige acquired by the aforesaid spring bedsteads, several
different types have appeared in the marketplace in which endeavour has been made
to avoid the laborious manufacture of the springs which have been replaced by simple
cross-pieces or rigid wooden slats with which flexibility, such a determining feature
of this piece of furniture, disappears, or endeavour has been made to replace the
wooden springs by springs made of other materials which would provide a certain degree
of flexibility, with the idea of lowering the price of the product and preventing
its possible deterioration. Endeavours have also been made along these lines using
metal rods and sheet, plastic materials and even combining metals with plastic.
[0006] Thus, in current state-of-the-art, we find forerunners of bedsteads made up of cross
pieces of various widths obtained from simple, compact, rigid wood as well as other
designs of flexible springs either made up simply of coated metal rods or metal rods
supplemented by metal flat strips or metal rods or strips coated with plastic materials
or, finally, by springs made with a complex structuring of areas and ribs obtained
wholly with plastic materials.
[0007] Despite the various, praiseworthy attempts referred to in the foregoing paragraph,
none have managed to compete in qualities with genuine wooden springs and the truth
is that nobody has triumphed in this attempt.
[0008] The applicant for this Patent, who has a singular experience in this type of manufactured
product through being the leading Spanish firm in spring bedstead manufacturing, is
fully aware of the disadvantages that wood brings to his products and of the possible
advantages that replacing wood by synthetic plastic materials could bring to his product,
as a natural consequence of the physical-chemical and mechanical properties intrinsic
to this kind of material.
[0009] Based on this possibility, quite some time ago, the applicant commenced profound
research directed towards replacing wooden springs by sections made in plastic materials.
These sections had been conceived in such a way that, whilst enjoying all the advantages
inherent to the very nature of the material employed, mechanical performance and the
material's behaviour on being used to make a bedstead's functional surface were at
least as effective as those provided by the wooden springs which it was intended to
replace. With this in mind, it was laid down that the section to be obtained would
have to behave elastically in the same way as the aforementioned wooden springs, that
its elastic hysteresis were less and that, finally, it would be totally stable to
weather conditions.
[0010] Having initially discarded complex shape structures and metal frameworks, efforts
along this line of research were directed towards achieving a type of section with
a simple, adequate format sufficiently reinforced by a continuous synthetic fibre
support. It would be a section which could be obtained from different thermostable
plastics.
[0011] To obtain the section required, an analysis was first made in order to find out the
exact stresses in quality and quantity that each area of the lamina in a bedstead
is supporting. This study managed to prove that 96% of the stresses are bending and
4% compressive in nature.
[0012] As a result of the research, work and tests carried out, the spring bedstead, the
subject matter of this Patent, was obtained, in which three fundamental components
are distinguished, made up, in fact, of the section itself, which is actually the
spring, the bushes for fitting them into the bedstead's frame and supplementary caps
perfecting the spring-to-bush assembly which, in turn, contribute towards the mattress
being stable on the bedstead.
[0013] The section, which is the spring itself, is characterized by having an inverted "U"
shaped cross section and short vertical arms compared to its broad horizontal stretch,
and said vertical arms, at a point nearly halfway up, converge inwards with respective
45° angles providing the section with bevelled longitudinal edges; this section can
be obtained from flat, crimped, woven, combed or braided fibres or a combination of
them; by subsequent injection onto them in a suitable press-mould of any type of thermostable
plastic material such as ortho- and isophthalic poliesters or any other equivalent,
either alone or with various organic and inorganic charges such as calcium phthalate,
calcium carbonate, talc or others and, during the process, adding small amounts of
other materials such as fabrics, threads, plastic films with a minimum thickness or
paper which, apart from influencing the section's behaviour, participate in the outside,
decorative finish of the spring; proportions of 70% fibre to 30% isophthalic resin
or plastic are foreseen and, to the effects of the deflection required in the spring's
body as a function of its length for different sizes of bedstead, it is laid down
that the section be obtained with a curvature between 4m and 9m radius.
[0014] The invention also provides for the possible addition of two narrow, longitudinal
projections on the spring's functional surface, as a continuation of the bevels of
its two short side faces. These projections are angular in cross section and define
two thin grooves which lead to perfect adaptation of the mattress to the bedstead
and prevent, it sliding, as well as respective reinforcing ribs in the centre of its
inside/ underneath part.
[0015] The invention's second component relates to the bushes which fit into the bedstead's
frame and house the ends of the springs, protecting them from friction and wear, since
frames are usually metal and movements in the springs as a result of their bending
capability must be prevented from ocurring on the frame's metal edges.
[0016] Made in plastic, these bushes have a slotted body exactly matching the spring, the
end of which they receive and, at their mouth facing towards the inside of the mattress,
their end side faces and bevelled edges noticeably emerge and are prolonged in thick
side lugs located in a plane perpendicular to the body in an approximately square
shape but with their outside vertices curved. This curvature is more marked at their
respective upper vertices.
[0017] Apart from improving the aesthetics of the bedstead, the supplementary caps, also
made in plastic, contribute towards improving the anchoring of the springs to the
frame and towards stabilizing the mattress on the bedstead. They ire essentially shaped
by a hollow body without a bottom, with a truncated parabola in plan view decreasing
in height from the widest part, where it matches the bedstead's frame, to its opposite
end, parallel and narrower, in which the height of this supplementary body practically
matches that of the springs. At their narrowest end, which faces towards the bedstead's
longitudinal centre line, these caps have a mouth coinciding in shape exactly with
the section of the springs and, from this mouth, three ribs begin and extend in parallel
fashion towards the inside of the cap, slightly increasing their height as the cap
itself does, acting as guides and adapting to the shape of the springs which are to
be located inside them. The two side ribs, which are the highest and are located on
both sides of the spring, are provided on their inside edge with small longitudinal
projections emerging towards the centre line of the cap and bevel shaped to hold the
spring when pressure is exerted on it when fitted in the bedstead. The aforesaid three
ribs do not reach the widest end of the cap so as to shape a clear space between them
and small side pieces which, at this widest end of the cap, close it off and allow
it to house and hold the spring receiving bush side lugs.
[0018] The elasticity required on the functional surface of each type and size of bedstead
is preset by the number of springs shaping it, as well as the width and thickness
of them. Therefore, coefficients of elasticity and firmness are constant parameters
for each bedstead made with wooden springs.
[0019] We see, then, that these coefficients of elasticity and firmness, as well as their
suitable regulating, constitute fundamental principles which must be taken into account
when designing the manufacture of a structured bedstead with a base formed with such
springs.
[0020] The aforementioned regulating is a further objective intended and achieved, in a
very simple but effective way, by this Patent using simple means allowing individual
regulation of the coefficients of elasticity and resistance of each of the various
springs making up the bedstead. This regulation can be calibrated and modified at
the user's will at any time he may deem fit.
[0021] The springs protected by the Patent are shaped from a special section adopting an
inverted "U" shape cross section with its short, vertical arms converging inwards
towards a broad horizontal stretch. The proportions of these sections vary both as
a function of the size of the bedsteads on which the springs are fitted and as a function
of the place each spring occupies in the bedstead's frame, since bedsteads are known
where their centre springs pertaining to the areas in which the bedstead has to support
greaters stresses are noticeably wider than springs located in areas near the bedstead's
headboard and footboard.
[0022] The Patent also provides for the section making up each spring to be given a slight
longitudinal curvature which determines the deflection defining its elastic capacity.
[0023] Whilst being used, each spring within the bedstead's framework withstands a pressure
exerted by the weight of the users and, thanks to this pressure and the springs's
elasticity, the spring undergoes a deformation of its initial design which is reflected
both in the arc of its longitudinal curvature and in the parallelism of the short
vertical sides given by the "U" cross section, the sides of which tend to diverge
outwards in order to absorb the bending stresses supported by the spring, whilst totally
or partially recovering its original shape as soon as the pressures being received
are removed or modified by virtue of the spring's intrinsic elasticity.
[0024] From the foregoing paragraph, it can be deduced that if we limit or prevent the springs
from deforming, we increase resistance to pressures and, consequently, we increase
the degree of strength of the bedstead's functional surface by a corresponding magnitude.
[0025] On the basis of this principle, this Patent has provided for simple spring elasticity
and strength regulating elements, each of which is made up of a totally rigid piece
in a general elongated rectangular prismatic shape, which offers the special feature
of having a transverse channel or hollow all the way through, also rectangular in
cross section, defining openings in its long sides. Like the rest of the hollow, these
side openings exactly match in size those of the section of the spring to which the
regulator is tightly fitted in order to facilitate its being moved along the spring.
On its shortest ends, this regulator thickens for reinforcement on both sides and
thus defines concave-knurled arching effects on the outside surface which facilitate
the regulator's manual sliding along the spring.
[0026] These regulators have + and - signs engraved on their top face, which is the most
visible. These signs are duly aligned in the vicinity of one of its ends and when
these regulators are fitted on a bedstead spring, the + sing appears on that side
of the regulator facing towards the bedstead's centre whilst the - sign is located
on the side nearest the bedstead's sides.
[0027] The mission fulfilled by these regulators, on tightly enveloping the springs to which
they are fitted, is to prevent divergence between the narrow side faces of the springs
and, thus, the latter confer greater firmness to the bedstead's surface on increasing
their resistance to pressure.
[0028] Manually operated, as we have already mentioned, these regulators are arranged preferibly
in pairs on each of the springs and, according to their location on them, make it
feasible to set their degree of resistance.
[0029] In fact, if we locate the two regulators of the same spring in the proximity of its
ends, next to the bedstead's frame where the spring is fitted and, therefore, prevented
from suffering any divergent deformation of its initial state, the spring's firmness
will not be changed by the action of these regulators, since the spring in question
will bend under the effects of the pressures it receives and the section's structure
will suffer the pertinent deformation along the rest of its length. This divergent
deformation will be more marked in the central areas of said spring.
[0030] If we move the regulators towards the central area in the direction of the + signs
engraved on their top, we lessen the length of the spring's deformable area and, therefore,
we increase its resistance. This resistance will increase as the regulators are being
moved to the most central position, where the maximum resistance which the springs
can attain occurs.
[0031] In order for the invention to be better understood, a practical form thereof is shown
in the adjoining drawings, as a example without any limiting scope.
[0032] Seen in cross section, Fig. 1 shows us two different sizes of the section making
up the springs as envisaged in the patent. The sizes of this section will naturally
adjust to the requirements and features of the bedstead it is intended to make in
each case.
[0033] Fig. 2 represents the bush in which the spring ends fit in front elevation, plan
and rear view, as well as a detail in perspective of this piece, making it easier
to understand.
[0034] Fig. 3 shows a section of the same bush through A-A′ in Fig. 2.
[0035] Fig. 4 shows another section of the same piece cut through B-B′ in Fig. 2.
[0036] Fig. 5 shows two views of the supplementary cap seen in elevation from its widest
end and seen in plan underneath without a bottom.
[0037] Fig. 6 is a section view of the same cap through C-C′ in Fig. 5.
[0038] Fig. 7 shows two views of the cap itself enabling us to see both its external configuration
and its internal structuring.
[0039] Fig. 8 and Fig. 9 give us a top and underneath view of the three basic bodies making
up this patent, i.e., spring, bush which receives one end of same and supplementary
cap as they are all fitted and mounted on a frame to make up the bedstead assembly,
which is not shown completely in the drawing as it is deemed unnecessary, since it
would be no more than a mere repetition of what is defined and represented in these
drawings.
[0040] Figure 10 represents in perspective a portion of a spring made in accordance with
the Patent.
[0041] Figure 11 is a schematic representation of a spring seen from the side to show us
its slight longitudinal curvature giving it its deflection.
[0042] Figure 12 shows us a view through A-A′ of Figure 11 when the spring is at rest.
[0043] Figure 13 is another similar view showing the spring when under pressure.
[0044] Figure 14 shows us a plan and elevation view of a spring strengthening regulator.
[0045] Figure 15 shows the same item in perspective.
[0046] Figure 16 shows a cross section through a spring coinciding with the positioning
of a regulator.
[0047] Finally, Figure 17 consists of a view in top perspective of a spring with its regulators,
fitted onto a bedstead frame.
[0048] In all the figures, we can see that the springs 9 are formed from an inverted "U"
shaped section with short vertical arms converging inwards to form the bevel 1 joining
the horizontal stretch 2 which is the spring's functional surface.
[0049] The invention has slight longitudinal projections 3 on this horizontal stretch 2
as can be seen specifically in Fig. 1. Their sole purpose is to improve the mattress's
seating on the bedstead.
[0050] The figures also show us the special arrangement of the spring receiving bush 11
in which its slotted body 4, shaped to the shape of the springs, and the lugs 5 which
emerge on both sides of its mouth can be seen.
[0051] Likewise, the cap 12 which, by means of its interior ribs 6 fits with the spring
9, is also shown. The spring is secured onto said ribs via the longitudinal projections
7 which emerge slightly at their bottom edge and are bevelled to face towards the
cap's centre line. These projections are located on the two side guide ribs 6.
[0052] The cap's two bush lug support pieces 8, which partially close off the cap 12 at
its widest end, can be seen in the drawings. Between the support pieces 8 on the caps
12 and the interior ribs 6 of this same cap we can see a small space in the figures,
since the ribs 6 do not reach the end of the cap and so this small space houses and
holds the lugs 5 of the bush 11 when the assembly is fitted to a bedstead frame 10
and the caps 12 anchor the springs and balance the bedstead's surface.
[0053] The drawings also show us how the springs 9, shaped in their initial structuring
with deflection f, deform the parallelism of their narrow vertical sides in the manner
as shown in lines BC-DE and B′C′-D′E′ when receiving pressure effects. Such deformation
is conditioned and made practically impossible thanks to the action of the rigid regulator
elements which fit their full length hollow space 13 to the cross section of the springs
9.
[0054] We can also see in the figures the sides of the same regulators concave in configuration
and with knurling 14 to facilitate moving them by hand as well as the + andsigns engraved
on their visible top face arranged so that the + sign is located on the side of the
regulator facing towards the bedstead's centre line whilst thesing faces the bedstead's
frame members.
[0055] The foregoing is a faithfull description of the subject matter of this Patent, in
which all those variants which do not alter the essential nature of what is being
claimed can be deemed as included.
1. A bedstead of springs made from compound materials of the type made up of a frame
structure and functional surface determined by a succession of transversal springs
fitted thereon, characterized by comprising three fundamental components made up by
a special section of the spring (9), bushes (11) for embedding same in the bedstead
frame (10) and supplementary caps (12) finishing off the spring-to-bush assembly.
2. A bedstead, as the foregoing claim, characterized because the section making up the
springs (9) adopts an inverted "U" shape cross section with short vertical arms with
a broad horizontal stretch (2). At a point nearly half way up their height, these
vertical arms break inwards towards the horizontal strecht, with respective 45° angles,
giving the section bevelled (1), longitudinal edges; this section is made from flat,
crimped, woven, combed or braided fibres or a combination of them; by subsequent injection
onto them in a suitable press-mould of any type of thermostable plastic material such
as ortho- and isophthalic polyesters or any other equivalent, either alone or with
various organic and inorganic charges such as calcium phthalate, calcium carbonate,
talc or others and, during the process, adding tiny amounts of other materials such
as fabrics, threads, plastic films with a minimum thickness or paper; proportions
of 70% fibre to 30% isophthalic resin or plastic employed are established, as well
as the section being obtained with a curvature between 4m and 9m radius, to the effects
of obtaining the deflection required in the spring's body.
3. A bedstead, as claim 2, characterized by having provided for two possible longitudinal
projections (3) on the spring's functional surface as a continuation to the bevels
(1) of its two short sides. These projections are angular in cross section in the
shape of fine grooves and provision is also made for possible longitudinal reinforcing
ribs on the inside/underneath part of the section itself.
4. A bedstead, as claim 1, characterized because the bushes (11), made in plastic, have
a slotted body (4) exactly matching the section of the spring whose end they receive
and, at their mouth, their side faces and bevelled edges noticeably emerge and are
prolonged in thick side lugs (5) located in a plane perpendicular to the body itself
in an approximately square shape with their outside vertices curved. This curvature
is more marked at their respective upper vertices.
5. A bedstead, as claim 1, characterized because the supplementary caps (12), also made
in plastic, are shaped by a hollow, bottomless body, as a truncated parabola in plan
view decreasing in height from the widest part, where it matches the bedstead's frame,
to its opposite end, parallel and narrower, in which the height of this supplementary
body practically matches that of the springs. At their narrowest end, which faces
inwards towards the bedstead's longitudinal centre line, these caps have a mouth coinciding
in shape exactly with the section of the springs and, from this mouth, three ribs
(6) begin and extend parallel towards the inside of the cap, slightly increasing their
height as the cap itself does, acting as a guide and adapting to the shape of the
springs which are to be located inside them. The two side ribs, which are the highest
and are located on both sides of the spring, are provided on their inside edge with
small longitudinal projections (7) emerging towards the centre line of the piece and
bevel shaped to hold the springs (9) when pressure is exerted on them when fitted
in the bedstead, and it is provided for the said three ribs not to reach the widest
final part of the cap in order to leave a clear space between these ribs and the small
side pieces (8) which, at this widest end of the cap, close it off and allow it to
house and hold the spring receiving bush side lugs (5).
6. A bedstead, as claim 2, characterized by having elements regulating the springs' elasticity
and firmness. Such elements are each made up of a totally rigid piece in a general
elongated rectangular prismatic shape providing the special feature of being hollow
(13) throughout crosswise, also rectangular in cross section, defining two openings
in its two long sides. These openings, as well as the rest of this hollow section,
exactly match in size the cross section of the spring (9) to which the regulator is
fitted. This latter has two reinforcing thickenings on its shortest ends which, on
the outside surface, define concave, knurled arcs (14) for moving them by hand.
7. A bedstead, as the foregoing claim, characterized because the spring's firmness regulating
elements have + and - signs engraved on their topside, which is the most visible,
duly aligned in the vicinity of one of their ends and located such that when these
regulators are fitted on a bedstead's springs, the + sign appears on the side of the
regulator facing the bedstead's centre whilst the - sign is located on the side nearest
the bedstead's frame.