U.S. patent application number 15/549744 was filed with the patent office on 2018-02-15 for method for producing an upholstery spring, upholstery spring, mattress, and upholstered furniture.
This patent application is currently assigned to AGRO HOLDING GMBH. The applicant listed for this patent is AGRO HOLDING GMBH. Invention is credited to WOLFGANG GROTHAUS.
Application Number | 20180042394 15/549744 |
Document ID | / |
Family ID | 55236385 |
Filed Date | 2018-02-15 |
United States Patent
Application |
20180042394 |
Kind Code |
A1 |
GROTHAUS; WOLFGANG |
February 15, 2018 |
METHOD FOR PRODUCING AN UPHOLSTERY SPRING, UPHOLSTERY SPRING,
MATTRESS, AND UPHOLSTERED FURNITURE
Abstract
A method for producing an upholstery spring, such as for
upholstered furniture or mattresses includes several steps. One of
the steps includes at least regionally applying a heat-sensitive
colour indicator to a spring steel wire before, during or after the
bending of the spring steel wire. The spring steel wire is heated
to at least the changeover temperature of the colour indicator. The
upholstery spring is then finished.
Inventors: |
GROTHAUS; WOLFGANG; (BAD
ESSEN, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AGRO HOLDING GMBH |
BAD ESSEN |
|
DE |
|
|
Assignee: |
AGRO HOLDING GMBH
BAD ESSEN
DE
|
Family ID: |
55236385 |
Appl. No.: |
15/549744 |
Filed: |
January 28, 2016 |
PCT Filed: |
January 28, 2016 |
PCT NO: |
PCT/EP2016/051784 |
371 Date: |
August 9, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21F 35/00 20130101;
A47C 27/068 20130101; B21C 51/00 20130101 |
International
Class: |
A47C 27/06 20060101
A47C027/06 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 23, 2015 |
DE |
10 2015 102 539.6 |
Claims
1. A method for producing an upholstery spring for upholstered
furniture or mattresses, comprising the following steps: at least
regionally applying a heat-sensitive colour indicator to a spring
steel wire before, during or after a bending of the spring steel
wire; heating the spring steel wire to at least a changeover
temperature of the colour indicator; and finishing the upholstery
spring.
2. The method according to claim 1, wherein the spring steel wire
is heated to above 250.degree. C. for heat treatment and activation
of the colour indicator.
3. The method according to claim 1, wherein the spring steel wire
is heated to a temperature between 280.degree. C. and 320.degree.
C. for heat treatment and activation of the colour indicator.
4. The method according to claim 1, wherein the colour indicator is
applied to the spring steel wire by an immersion bath.
5. The method according to claim 1, wherein the colour indicator is
applied with a thickness between 0.05 .mu.m to 1.5 .mu.m.
6. The method according to claim 1, wherein a copper-containing
coating is applied as the colour indicator.
7. The method according to claim 1, wherein the colour indicator is
applied only in some regions to the spring steel wire.
8. The method according to claim 7, wherein the colour indicator is
applied to a central region of the upholstery spring, which central
region deforms upon loading.
9. An upholstery spring, produced by a method for producing the
upholstery spring for upholstered furniture or mattresses, the
method comprising the steps of: at least regionally applying a
heat-sensitive colour indicator to a spring steel wire before,
during or after a the-bending of the spring steel wire; heating the
spring steel wire to at least a the-changeover temperature of the
colour indicator; and finishing the upholstery spring.
10. A mattress with an upholstery spring, where the upholstery
spring is produced by the method of claim 9.
11. A unit or piece of upholstered furniture formed with an
upholstery spring produced by the method of claim 9.
12. The mattress produced according to the method of claim 10,
further comprising a step of providing a viewing window on a cover
for the upholstery spring or a unit comprising a plurality of
upholstery springs.
13. The unit or piece of upholstered furniture produced according
to the method of claim 11, further comprising a step of providing a
viewing window on a cover for the upholstery spring or a unit
comprising a plurality of upholstery springs.
Description
[0001] The present invention relates to a method for producing an
upholstery spring, in particular for upholstered furniture or
mattresses, an upholstery spring, a mattress and upholstered
furniture.
[0002] DE 10 2013 103 644 discloses a spring of a spring core which
is made of wire and can be used, for example, for mattresses or
upholstered furniture. The spring consists of a helically wound
spring steel wire that deforms when loaded. Such springs have
proven to be useful in the manufacture of upholstered furniture and
mattresses, wherein the springs are heat-treated in production in
order to make them tougher. A heat treatment of this type prevents
a drop in individual springs and the resulting depressions such as
troughs in cushions or mattresses. However, it can only be
determined with great effort whether adequate heat treatment was
performed. As a rule, a check is not possible for the end user.
[0003] It is therefore the object of the present invention to
provide a method for producing an upholstery spring, in which it is
possible to ensure in a simple manner that adequate heat treatment
has been carried out. Furthermore, a mattress and upholstered
furniture with such an upholstery spring should be provided.
[0004] In order to achieve this object, the method for producing an
upholstery spring provides that a heat-sensitive colour indicator
is applied at least in sections to a spring steel wire before,
during or after the bending of the spring steel wire, and then the
spring steel wire is heated to at least the changeover temperature
of the colour indicator before the upholstery spring is completed.
By applying the heat-sensitive colour indicator it is ensured that
the heat treatment of the spring steel wire can be rendered
visually visible. By means of a corresponding colour change, it is
recognizable for the manufacturer of upholstered furniture and
mattresses as well as for the end customer whether a heat treatment
was made which makes the spring steel wire tougher. As a result, an
important quality criterion can be visually emphasized for
upholstery springs.
[0005] Preferably, the spring steel wire is heated to above
280.degree. C. during the heat treatment. For heat treatment, the
spring steel wire can, for example, be heated to a temperature of
between 290.degree. C. to 310.degree. C., wherein the duration of
the heat treatment can be configured depending on the spring steel
wire used, but the temperature above 290.degree. C. must be reached
at least briefly. The changeover temperature of the colour
indicator is therefore also preferably at least 250.degree. C., in
particular between 290.degree. C. and 310.degree. C. The positive
effects by the heat treatment occur at these temperatures.
[0006] For effective production of the upholstery spring, the
colour indicator can be applied by an immersion bath. The coating
can occur in a purely electrochemical manner or galvanically by
applying a voltage. The colour indicator preferably has a thickness
between 0.05 to 1 .mu.m, in particular 0.10 and 0.80.mu.m, so that
the colour indicator is applied to the spring steel wire only in
small amounts.
[0007] Preferably, a copper-containing coating is applied as a
colour indicator, which does not adversely affect the mechanical
properties of the upholstery spring. The copper-containing coating
can also essentially consist entirely of copper, which is applied
to the spring steel wire with a low layer thickness. It is also
possible to use suitable copper alloys in order to set a certain
transition temperature. In the case of the colour change, the
copper-coloured coating is then darker or lighter, depending on the
temperature reached, which is clearly visible.
[0008] In a further embodiment of the invention, the colour
indicator is applied to the spring steel wire only in some areas,
which is particularly material-saving. The colour indicator can,
for example, be applied only to a central region of the upholstery
spring, which deforms upon loading, so that the colour indicator at
least indicates whether the deforming region has been heat-treated.
Then the end rings of an upholstery spring which are arranged at
opposite sides can remain uncoated. Of course, it is also possible
to completely coat the upholstery spring with the colour
indicator.
[0009] According to the invention, an upholstery spring is also
provided, which is used in particular in a mattress or a piece of
upholstered furniture. It is possible for a mattress or a piece of
upholstered furniture that a viewing window is provided in a cover
for the upholstery spring or a unit comprising a plurality of
upholstery springs so that an end customer can also recognize
whether the upholstery spring has been correspondingly
heat-treated.
[0010] The invention is explained in more detail below with
reference to an exemplary embodiment shown in the attached
drawings, wherein:
[0011] FIG. 1 shows a photographic view of an upholstery spring
with a coating of a colour indicator according to the invention
before and after the heat treatment, and
[0012] FIG. 2 shows a conventional upholstery spring without a
colour indicator.
[0013] FIG. 2 shows an upholstery spring without a coating of a
heat-sensitive colour indicator.
[0014] It can be seen that the spring steel wire from which the
upholstery spring is made has the same colour everywhere and it is
not optically apparent whether a heat treatment has been carried
out with this upholstery spring in order to make the spring steel
wire tougher.
[0015] On the left side in FIG. 1, an upholstery spring according
to the present invention is shown. The upholstery spring is
helically wound in a middle region between two end rings arranged
in parallel and is coated in this central region with a
heat-sensitive colour indicator. As can be seen from the view, the
central region has a different colour from the two uncoated end
rings of the upholstery spring. The middle region is clearly
darker, which is caused by the colour change of the heat-sensitive
colour indicator as a result of the heat treatment. On the right
side, an upholstery spring with colour indicator and without heat
treatment is illustrated. It can be seen clearly that the colour is
uniform. As a heat-sensitive colour indicator, a copper-containing
coating was applied to the wire electrochemically in a thickness of
between 0.15 .mu.m to 0.75 .mu.m. For this purpose, the wire was
passed through an immersion bath and a voltage was applied to the
spring steel wire, so that the copper-containing material was
deposited on the surface. By means of this method, the layer
thickness and the coated regions can be adjusted comparatively
exactly.
[0016] In this case, the colour indicator can be applied to the
still undeformed spring steel wire, so that the latter can be
deformed into the shape of an upholstery spring only after coating.
Preferably, a complete coating is then applied. However, it is also
possible first to form the spring steel wire into an upholstery
spring and at least partially coat the already formed spring steel
wire.
[0017] After applying the colour indicator, the bent spring steel
wire was subjected to a heat treatment, wherein the bent spring
steel wire is heated to a temperature between 210.degree. C. to
250.degree. C. By heating to this temperature, the colour indicator
was activated so that an optically recognizable colour change was
made in the middle region.
[0018] In the exemplary embodiment shown, only the middle region of
an upholstery spring is coated with a colour indicator, wherein it
is also possible to apply the colour indicator completely to the
upholstery spring. Through the coating of the colour indicator in
sections, it is easier to visually recognize the colour change by
the heat treatment. In addition, it is possible to provide the
coating only in the area of the upholstery spring, which deforms
upon loading, i.e. in particular the region between the two end
rings.
[0019] The upholstery spring can be bent to form different spring
types. Thus, the upholstery spring can be used as a Bonell spring,
a pocket spring, an open coil or as a different type of spring. The
upholstery springs can also be combined into a plurality of
upholstery springs and then processed into mattresses or
upholstered furniture.
[0020] In order to enable the end customer to check whether
high-quality upholstery springs have been used in the mattress or
the upholstered furniture, at least one transparent viewing window
or one formed by a recess can be provided in the cover so that an
optical check is possible as to whether the upholstery spring is
heat-treated.
* * * * *