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(11) | EP 0 941 962 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | An inner spring fit inside furniture and bedding and a producing method therefor |
| (57) An inner spring fitted inside furniture and bedding comprises a coil spring(3) accommodated
in each of cylindrical bags(20) having a predetermined number of spring accommodating
portions continuously arranged in parallel and that the coil springs(3) of at least
partly different in resilient force are inserted into said cylindrical bags(20), whereby
a row of inner springs of at least partly different in resilient force are formed. A hardening section(4) for a hardening process of a method for producing the inner spring comprises a control unit(9) for controlling the time required for said coil spring(3) to be energized for the hardening and an energizing device(7,7) for allowing power fed from said control unit(9) to pass through said coil spring(3) and that the power applied from said control unit(9) is varied so that said coil springs(3) to be fed to said bag insertion process(5) can be allowed to be at least partly different in resilient force. |
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The present invention relates to an inner spring fitted inside furniture, such as chairs and sofas, and bedding such as mattresses of beds. It is noted that the terms of "furniture" and "bedding" used herein are intended to embrace any seats in, for example, trains and motorcars, in the broad sense, without limiting to the examples above.
[0002] In general type inner spring fabricating apparatuses, expensive and high resilient, oil tempered, wire rods are used to enhance resilience and durability of coil springs, because coil springs made of general wire rods present problems in resilience and durability.
[0003] However, those wire rods are strong in resilience, thus presenting a problem that the coil springs have to be fabricated at much expense in time and labor. Besides, since those coil springs are low in production and yet the wire rods are expensive, thus presenting a problem of increasing manufacturing costs.
[0004] In general, a row of contained coil springs is produced by the method that each of the coil springs, which are fabricated continuously by the coil spring fabricating apparatus, is inserted in order in between a non-woven fabric or a sheet as folded into double, and then the non-woven fabric or the sheet are sealed. In this method, each individual contained coil spring cannot be changed in diameter.
[0005] To allow the row of the coil springs to have partially different resilient forces with respect to a direction of a length L of, for example, a mattress of a bed by the conventional method, it is required that a plurality of rows of inner springs, each row including therein coil springs 103a, 103b, ... different in diameter, are prepared, among which proper rows of inner springs 103a, 103b, ... including therein coil springs 103a, 103b, ... of required diameters for required resilient forces are selected to be properly arranged in the widthwise direction W and connected in order, so as to form the mattress 15 of the bed, as shown in FIG. 6.
[0006] In this conventional method, a plurality of apparatuses specialized for required diameters of the wire rods are needed for producing a plurality of rows of contained coil springs including coil springs having different diameters and also the lengths of the rows of contained coil springs must be inefficiently changed in accordance with variations in width W of the mattresses.
[0007] To solve these problems, the applicant has previously proposed an inner spring fabricating apparatus (Japanese Laid-open Patent Publication No. Hei 9-173673), which is so designed that the coil springs are energized to be heated so as to be hardened and are sequentially inserted into cylindrical bags having a predetermined number of spring accommodating portions which are continuously formed in parallel.
[0008] However, the coil springs fabricated by the inner spring fabricating apparatus previously proposed by the applicant as well as by the above-described general type ones are all uniform in resilient force. Because of this, the mattress, in which a plurality of rows of conventional coil springs, each having an uniform resilient force, are connected, becomes uniform in resilient force over the whole area, although the distribution of weight through the mattress is not uniform, as illustrated in FIG. 6 showing that the mattress is weighted light at its portions corresponding to the head and legs but is weighted heavy at its portions corresponding to the trunk. Thus, the mattresses thus produced had a disadvantage of being not able to suit for the non-uniform distribution of weight.
[0009] One possible approach for allowing the coil springs to have different resilient forces to suit for such a non-uniform distribution of weight is to use wire rods of different diameters for the coiled springs. But, in this case, a plurality of coil spring fabricating apparatuses specialized for required diameters of individual wire rods are needed for producing the coil springs. This presents a further problem of needing a large space in a work-shop for installation of machines, storage of a variety of wire rods and the like.
[0010] In addition, each of the coils springs separately produced by the coil spring fabricating apparatuses must be adequately controlled to be accurately held in position in the spring accommodating portions of the cylindrical bags, thus arising still further problems of needing much time and labor to reduce productivity and of being high in probability of miss-holding to provide reduced quality and reliability.
[0011] Another approach is that various kinds of inner springs of different diameters aligned in rows (the coil springs held in each row of inner springs are all equal in diameter) are produced by a plurality of inner spring producing apparatuses, among which proper rows of inner springs including coil springs of required diameters are selected and are connected in order so that they can be arranged in the widthwise direction W of the mattress, as shown in FIG. 7. This approach can produce resilient forces partially different with respect to the length L of the mattress, but this still has a disadvantage that the lengths of the rows of contained coil springs must be changed in accordance with variations in width of the mattresses, thus involving various problems in addition to the above-described problems.
SUMMERY OF THE INVENTION
[0012] The present invention has been proposed in the light of various problems involved in the prior art as mentioned above. It is the object of the invention to enable each coil spring of a desired resilient force to be readily and accurately fitted in a desired place to improve productivity and reliability and reduce the manufacturing costs.
[0013] In order to accomplish the above-described object, an inner spring fitted inside furniture and bedding according to the invention comprising a coil spring accommodated in each of cylindrical bags having a predetermined number of spring accommodating portions continuously arranged in parallel, the coil springs being received, with their axes being in parallel, is so constructed that the coil springs of at least partly different in resilient force are inserted into the cylindrical bags, whereby a row of inner springs of at least partly different in resilient force can be formed.
[0014] A method for producing an inner spring fitted inside furniture and bedding according to the invention comprising the processes of: forming a coil spring; hardening the coil spring formed in the coil spring forming process; and inserting the hardened coil spring into each of cylindrical bags having a predetermined number of spring accommodating portions continuously arranged in parallel is characterized in that a hardening section for the hardening process comprises a control unit for controlling the time required for the coil spring to be energized for the hardening and an energizing device for allowing power fed from the control unit to pass through the coil spring and that the power applied from the control unit is varied so that the coil springs to be fed to the bag insertion process can be allowed to be at least partly different in resilient force.
[0015] Further, variation in power applied from the control unit should preferably be within the range of from 20 V to 40 V in voltage and from 0.1 sec. to 0.4 sec. in energization time.
[0016] Other objects, features and advantages of the invention will be fully understood from a consideration of the following description taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017]
FIG. 1 is a schematic side view of an apparatus of the invention for fabricating an inner spring fitted inside furniture and bedding;
FIG. 2 is a side view of a hardening section of the apparatus of the invention for fabricating an inner spring fitted inside furniture and bedding;
FIG. 3 is a perspective view of inner springs fabricated by the apparatus of the invention for fabricating an inner spring fitted inside furniture and bedding;
FIG. 4 is a side view of the inner springs fabricated by the apparatus of the invention for fabricating an inner spring fitted inside furniture and bedding;
FIG. 5 is a plan view of a structural portion of a mattress formed by connecting the inner springs fabricated by the apparatus of the invention for fabricating an inner spring fitted inside furniture and bedding;
FIG. 6 is a perspective view of a bed using the inner springs fabricated by the apparatus of the invention for fabricating an inner spring fitted inside furniture and bedding; and
FIG. 7 is a plan view showing the state of conventional type inner springs being connected in a mattress form.
DETAILED DESCRIPTION OF THE PREFFERED EMBODIMENT
[0018] An inner spring fitted inside furniture and bedding and a producing method therefor according to the invention will be described below with reference to the accompanying drawings.
[0019] First, an inner spring fabricating apparatus of the invention will be described below with reference to the accompanying drawings.
[0020] FIG. 1 is a side view schematically showing the inner spring fabricating apparatus. Indicated by the reference numeral 1 in the Figure is the entirety of the inner spring fabricating apparatus.
[0021] The inner spring fabricating apparatus 1 comprises a coil spring forming section 2 for forming coil spring 3; a hardening section 4 for hardening the coil spring 3 formed in the coil spring forming section 2; and a bag insertion section 5 for inserting the hardened coil spring 3 into each of cylindrical bags formed in a row. The processes in the respective sections are substantially the same as those in the inner spring fabricating apparatus previously proposed by the applicant (Japanese Laid-open Patent Publication No. Hei 9-173673).
[0022] The hardening section 4 comprises a carrier mechanism 21 composed of an endless drive chain or equivalent supporting thereon spring supporting rods 6 which are each inserted in sequence into the interiors of the coil springs 3, which are intermittently fed in order from the coil spring forming section 2, to support the coil springs in sequence and carry them to the bag insertion section 5 intermittently; electrodes (energizing devices) 7, 7 which are contactable with upper and lower peripheral edges of the coil spring 3 at a specified point of the carrier mechanism 21, as shown in FIG. 2, to energize each of the coil springs 3; and a cooling mechanism 8 for blowing air over the hardened coil springs 3, which are being intermittently carried with being supported by the coil spring supporting rods 6, to cool them. The hardening section 4 is equipped with a control unit 9 for controlling the time (energization time) for the coil spring to be energized for the hardening.
[0023] The control unit 9 has a control box 10 containing a control circuit for controlling the overall drive of the entire apparatus; an electric current control circuit for controlling electric current required for the coil springs 3 to be hardened in the hardening section 4; and an electric-current feeding time setting circuit comprising a plurality of timers. The circuits are adapted to be controlled for drive on the basis of numerical values set by a ten-key pad 11 equipped in the control box 10.
[0024] Next, the way how a row (rows) of inner springs 13 shown in FIGS. 3-5 is/are produced by the thus constructed inner spring fabricating apparatus 1 will be described below.
[0025] First, a wire rod is formed into a coiled form having a predetermined length in the coil spring forming section 2 and thereafter is fed to the hardening section 4. In the hardening section 4, the thus formed coil springs are hardened under conditions of specified voltages and set electric currant feeding time. Thereafter, the hardened coil springs 3 are cooled by cooling air applied from a blower 12 through the cooling mechanism 8 so as to be given desired resilient forces and then are fed to the bag insertion section 5.
[0026] Detailed description on how the coil springs are hardened in the hardening section 4 will be given here. The data on the number (Z) of coil springs 3 forming each row of inner springs 13 and the data on the voltage and electric current feeding time required for the 1st to a Kth coil springs 3 to be energized for the hardening; the voltage and electric current feeding time required for the Kth + 1 to a Nth coil springs 3 to be energized for the hardening; the voltage and electric current feeding time required for the Nth + 1 to a Xth coil springs 3 to be energized for the hardening; the voltage and electric current feeding time required for the Xth + 1 to a Yth coil springs 3 to be energized for the hardening; and the voltage and electric current feeding time required for the Yth + 1 to a Zth coil springs 3 to be energized for the hardening are entered in advance into the electric current control circuits and the electric-current feeding time setting circuits comprising a plurality of timers. The coil springs are hardened on the basis of those input data. The voltages are selectively set within the range of 20V to 40V and the time (energization time) for the coil springs to be energized for the hardening is selectively set within the range of 0.1 sec. to 0.4 sec..
[0027] This is because voltages over 40V increase possibilities of electric shock hazards and require instantaneous energization to make it difficult to uniformly harden the overall coil spring, while on the other hand, voltages of less than 20V make a temperature rise difficult and need much time for the hardening, thus causing significant reduction of productivity.
[0029] Specifically, with the maximum voltage level of 40V, it takes 0.1 sec. for sufficient hardening effect, while, with the minimum voltage level of around 20V, it takes 0.4 second for the hardening effect. An excess hardening makes the coil spring brittle and reduces its durability, while, an insufficient hardening reduces its resilient force. In consideration of these facts, the energization time is properly determined.
[0030] According to the example of the invention, the voltage is set at 30V and the electric current feeding time for the 1st to a Kth coil springs to be energized for the hardening is set to be 0.1 sec.; that for the Kth + 1 to a Nth coil springs is set to be 0.2 sec.; that for the Nth + 1 to a Xth coil springs is set to be 0. 3 sec.; that for the Xth + 1 to a Yth coil springs is set to be 0.2 sec.; and that for the Yth + 1 to a Zth coil springs is set to be 0.1 sec..
[0031] The coil springs 3 fed from the hardening section 4 to the bag insertion section 5 are compressed by a coil spring press-in mechanism 14 to be inserted into non-woven fabrics or breathing sheets which are folded into double to be formed into a cylindrical bag form. The bags are sealed by a sealing mechanism (not shown) to thereby produce a row of inner springs 13 in which a plurality of coil springs 3 are respectively inserted into the cylindrical bags 20, as shown in FIGS. 3 and 4.
[0032] Rows of inner springs 13 as hardened are so connected via adhesive or hook rings, as shown in FIG. 5, to form a mattress 15 of a bed. As a result of this, the mattress 15 has resilient forces partly varied with respect to the lengthwise direction L of the mattress 15.
[0033] This enables the mattress to have a small resilient force at its portions 16 and 17 corresponding to the head and legs; a large resilient force at its portion 18 corresponding to the trunk; and a smallest resilient force at its rest portions 19, as shown in FIG. 6, to well suit for the distribution of weight.
[0034] Although the mattress 15 of the bed has a variety of sizes, including the so-called, single size, semi-double size, double size, queen size and king size, it commonly has a substantially uniform lengthwise dimension of about 2 m. Accordingly, the way of rows of inner springs being arranged in parallel in the longitudinal direction, as in the example of the invention, enables the width W to be changed with efficiency by simply increasing or decreasing a row of contained inner springs to be connected, without the need for changing the length L of a row of contained inner spring, as in the conventional.
[0035] In the embodiment of the invention, the respective sections of the inner spring fabricating apparatus are arranged in series from the coil spring forming section to the bag insertion section, but those sections may, of course, be separated so that each process can be done in different places.
[0036] As discussed above, the invention is so constructed that the coil springs different in resilient force are inserted into the cylindrical bags of the predetermined number of spring accommodating portions being continuously arranged in parallel, to form a row of inner springs. This construction enables a mattress of a bed, for example, to have different resilient forces with respect to the widthwise direction of the mattress of the bed by simply arranging the rows of inner springs in parallel. This can provide the advantageous effect of providing improved productivity with significantly reduced manufacturing costs.
[0037] Also, since the coil springs having the resiliency suitable for the distribution of weight exerted on the mattress of the bed can be fabricated with ease, the fatigue of the mattress can be prevented as permanently as possible. This can provide the advantageous effect of providing an improved durability of bedding, such as beds, and furniture and thus an improved quality of goods.
[0038] In addition, since the coil springs, which are inserted into the spring accommodating portions to form a row of inner springs, can be changed in resilient force with ease in the hardening section before the bag insertion section by varying the time for the coil spring to be energized, one inner spring fabricating apparatus is simply needed and also one kind of wire rod to be worked is only needed. This can provide the advantageous effect of eliminating the need for the large space in a work shop for installation of machines, storage of a variety of wire rods and the like.
[0039] Further, since the coil springs set at different resilient forces by the hardening apparatus, are inserted in the spring accommodating portions in the bag insertion section in the order in which they are set at different resilient forces, the need for each of the coils springs separately produced by several coil spring fabricating apparatuses being adequately controlled, as in the prior art, can be eliminated. In addition, since the miss-holding of the coil springs in the spring accommodating portions of the cylindrical bags can be surely prevented, there can produce the advantageous effect of providing significantly improved reliability of the bedding, such as beds, and furniture.
[0040] It is to be understood that the embodied form presented in the detailed description of the invention is only for the purpose of clarifying the technical contents of the invention, and accordingly the invention should not be construed in the narrow sense by limiting to any of the embodied forms, and that various changes and modifications may be made without departing from the sprit or scope of the following claims.
1. An inner spring fitted inside furniture and bedding comprising a coil spring accommodated
in each of cylindrical bags having a predetermined number of spring accommodating
portions continuously arranged in parallel, said coil springs being received, with
their axes being in parallel, characterized in that said coil springs of at least
partly different in resilient force are inserted into said cylindrical bags, whereby
a row of inner springs of at least partly different in resilient force are formed.
2. A method for producing an inner spring fitted inside furniture and bedding comprising
the processes of: forming a coil spring; hardening said coil spring formed in said
coil spring forming process; and inserting the hardened coil spring into each of cylindrical
bags having a predetermined number of spring accommodating portions continuously arranged
in parallel, characterized in that a hardening section for the hardening process comprises
a control unit for controlling the time required for said coil spring to be energized
for the hardening and an energizing device for allowing power fed from said control
unit to pass through said coil spring and that the power applied from said control
unit is varied so that said coil springs to be fed to said bag insertion process can
be allowed to be at least partly different in resilient force.
3. A method for producing inner springs fitted inside furniture and bedding as set forth
in Claim 2, wherein variation in power applied from said control unit is within the
range of from 20 V to 40 V in voltage and from 0.1 sec. to 0.4 sec. in energization
time.