EP0985369A1

EP0985369A1 - Assembled structure of inner springs to be fit inside furniture and bedding and a producing method therefor

Info

Publication number: EP0985369A1
Application number: EP99305290A
Authority: EP
Inventors: Hiroyuki Eto
Original assignee: Matsushita Industrial Co Ltd
Current assignee: Matsushita Industrial Co Ltd
Priority date: 1998-09-09
Filing date: 1999-07-02
Publication date: 2000-03-15

Abstract

An assembled structure of the inner springs to be fit inside furniture and bedding comprises rows of inner springs (2), each row of inner springs comprising a predetermined number of coiled springs and accommodating bags with a predetermined number of spring accommodating portions arranged in series, the coiled springs in each row being accommodated one in each of the accommodating bags, the rows of inner springs being arranged in parallel and joined to each other at side walls of the spring accommodating portions, to be formed into a mat form; and
a connecting sheet (13) of low stretching properties having front and rear surfaces and interposed between side portions of the adjoining rows of inner springs (2), each of the front and rear surfaces forming on at least a part thereof an adhesive bonding surface (20) via which the adjoining rows of inner springs are connected to one another at their side portions.

Description

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an inner spring to be fitted inside furniture including chairs and sofas, and bedding including mattresses of beds.
It is noted that the terms of "furniture" and "bedding" used herein are intended to embrace any seats used in, for example, trains and motorcars, in the broad sense, without limiting to the examples above.

Description of the Prior Art

Various methods for assembling an inner spring structure of this nature have been adopted hitherto, including the method of joining adjoining inner springs to each other by C-shaped rings of a wire rod being fastened with a tool and the method of joining adjoining inner springs to each other by being threaded at their trunk portions with a thick thread by a long needle. However, these conventional methods had disadvantages of significantly poor productivity and of impairment of properties of the inner springs.
Recently, as disclosed in the US Patent Publication No. 4,578,834, the method of applying a hot melt adhesive to side surfaces of the rows of inner springs to adhesive bond the adjoining inner spring rows to each other has been adopted a lot. This method however has difficulties in suppressing the tendency of the rows of inner springs to expand and contract in the direction of the rows (longitudinal direction) L, thus causing a deformation of a mat and the like, disadvantageously.
For attempts to eliminate this deformation problem, another method has been proposed of covering the mat or equivalent with a net to prevent deformation of its closing line with the aid of the net. However, this method has a lot of drawbacks of: impairing resiliency in the individual springs which is a property of the inner spring; increasing costs; reducing productivity; etc..

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve the disadvantages and drawbacks mentioned above at a stroke. It is the object of the present invention to provide an assembled structure of the inner springs of high quality without impairing the resiliency of individual springs which is the most characteristic of the inner spring and with an improved product efficiency and reduced costs.
To accomplish the abovesaid object, an assembled structure of inner springs to be fit inside furniture and bedding according to the invention comprises: rows of inner springs, each row of inner springs comprising a predetermined number of coiled springs and accommodating bags with a predetermined number of spring accommodating portions arranged in series, the coiled springs in each row being accommodated one in each of the accommodating bags and the rows of inner springs being arranged in parallel and joined to each other at side walls of the spring accommodating portions, to be formed into a mat form; and a connecting sheet of low stretching properties having front and rear surfaces and interposed between side portions of the adjoining rows of inner springs, each of the front and rear surfaces forming on at least a part thereof an adhesive bonding surface via which the adjoining rows of inner springs are connected to one another at their side portions.
Further, the connecting sheet may be formed of a non-woven fabric or a woven fabric or a knitted fabric. Further, the adhesive bonding surface may be formed by the intermittent application of an adhesive to each of the front and rear surfaces of the connecting sheet.
In addition, a producing method for an assembled structure of inner springs to be fit inside furniture and bedding according to the invention comprises the steps of: applying an adhesive to at least a part of each surface of a connecting sheet; bringing the connecting sheet into contact with a side surface of an earlier row of inner springs and then bringing a side surface of a next row of inner springs into press-contact with the connecting sheet so that the next row of inner springs can be adhesive bonded to a side surface of the earlier row of inner springs through the connecting sheet; and repeating the same operations in sequence to produce an assembled structure of a mat-formed inner springs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a schematic of a fabricating apparatus for an assembled structure of inner springs of the present invention;
FIG. 2 is a front view of a part of the fabricating apparatus for an assembled structure of inner springs of the present invention;
FIG. 3 is a side view of rows of inner springs adhesive bonded to each other by the fabricating apparatus for an assembled structure of inner springs of the present invention;
FIG. 4 is a plan view of the assembled structure for inner springs formed by use of the rows of inner springs fabricated by the apparatus for the assembled structure of inner springs of the present invention;
FIG. 5 is a schematic plan view of a conventional assembled structure of inner springs, showing the state of the rows of inner springs expanding and contracting in the longitudinal direction;
FIG. 6 is a schematic plan view of a conventional assembled structure of inner springs, showing the deformation by the rows of inner springs expanding in the longitudinal direction.

DETAILED DESCRIPTION OF THE EMBODIMENT

Referring now to the accompanying drawings, examples of the preferred embodiment of the present invention directed to an assembled structure of inner springs to be fitted inside furniture and bedding, and a producing method therefor will be described below. It is to be understood, however, that the scope of the invention is by no means limited to the illustrated embodiments.
FIG. 1 is a side view of a fabricating apparatus for an assembled structure of inner springs of the present invention, and FIG. 2 is a front view of a part of the fabricating apparatus. Numeral 1 designates the entirety of the fabricating apparatus for the assembled structure of inner springs.
In the fabricating apparatus 1 for the assembled structure of inner springs, a wire rod is curled into a coiled form in an earlier step (not shown), and the curled wire rod is cut off and hardened to form coiled springs. Thereafter, the coiled springs thus formed are arranged in series and are accommodated one in each of the accommodating bags, to form rows of inner springs. Then, the rows of inner springs are connected to each other at their side portions so as to be formed into a mat form. The fabricating apparatus 1 comprises a carrying mechanism portion 3 for carrying the rows of inner springs 2 formed in the earlier step; and an adhesive bonding mechanism portion 4 for adhesive bonding the rows of inner springs 2 carried by the carrying mechanism portion 3 to each other.
The carrying mechanism portion 3 comprises a conveyor 5 for carrying the rows of inner springs formed in the earlier step to a lateral side of the adhesive bonding mechanism portion 4; and a carrier 6 which is so structured as to be movable in reciprocation over the conveyor 5 and between the conveyor 5 and the adhesive bonding mechanism portion 4.
The carrier 6 comprises pairs of pawls 8, 8 each pair of which are slid toward and away from each other by means of driving cylinders 7, 7, in association with its reciprocating movement between the conveyor 5 and the adhesive bonding mechanism portion 4, to hold each inner spring at the opposite ends 2a, 2b; and an elevating cylinder 9 for moving the pairs of pawls 8, 8 up and down.
The adhesive bonding mechanism portion 4 comprises a holder 10 for holding an earlier row of inner springs 2 supplied through the carrier 6; and a connecting sheet supply portion 11 for bringing the earlier row of inner springs 2 held by the holders 8 and a next row of inner springs 2 to be adhesive bonded together.
The connecting sheet supply portion 11 comprises, as shown in FIGS. 1 and 2, a catcher 14 which holds an end of a connecting sheet 13 paid out from a sheet roll 12 and draws out the connecting sheet 13 therefrom to extend over the earlier row of inner springs 2 held by the holder 10; a pair of adhesive spray nozzles 15, 15 for a hot melt adhesive 20 to be intermittently sprayed to front and rear surfaces of the drawn-out connecting sheet 13 in association with the reciprocating motion of the catcher 14 over the row of the inner springs 2; and cutters 16 disposed at a position downstream from the adhesive spray nozzles 15, 15 with respect to the direction for the connecting sheet 13 to be drawn out.
The holding and drawing of the catcher 14, the intermittent spray of the hot melt adhesive 20 from the adhesive spay nozzle 15, 15 and the cutting of the cutters 16 are associated in operation with each other from after the earlier row of inner springs 2 is held in the holder 10 by means of the carrier 6 until the next row of inner springs 2 is supplied to the holder 10 by means of the carrier 6.
In the thus constructed fabricating apparatus 1 for the assembled structure of inner springs, after the row of inner springs 2 is carried to the adhesive bonding mechanism portion 4 through the conveyer 5 from the former step, the pairs of pawls 8, 8 are moved down by means of the elevating cylinder 9 and actuated by means of the driving cylinders 7, 7, to firmly hold the as-carried row of inner springs 2 at their opposite ends. The row of inner springs 2 held at their opposite ends 2a, 2b by the pairs of pawls 8, 8 are moved up by means of the elevating cylinder 9, are moved toward the holder 10, and then moved down by means of the elevating cylinder 9, to be pushed in and held by the holder 10.
After the earlier row of inner springs 2 is held by the holder 10, the connecting sheet 13 of the sheet roll 12 cut off in the former step is held at the end by the catcher 14, first, before the next row of inner springs 2 is supplied to the holder 10.
Then, the catcher 14 holding the end of the connecting sheet 13 is moved from one end of the row of inner springs 2 at the cutter 16 side to the other side thereof, when the connecting sheet 13 is paid out from the sheet roll 12.
In association with the paying-out of the connecting sheet 13, the molten adhesive 20 is applied to each of the front and rear surfaces of the connecting sheet 13 from the adhesive spray nozzles 15, 15 by intermittent spraying.
The adhesive 20 from the adhesive spray nozzles 15, 15 may be applied in a continuous or discontinuous bead form or in a spot form.
When the catcher 14 reaches the other end of the row of inner springs 2, the spray of the adhesive 20 from the nozzles 15, 15 is brought to a stop and the cutter 16 is actuated to cut off the connecting sheet 13.
Along with the actuation of the cutter 16, the catcher 14 is released from its holding the end of the connecting sheet 13, so that the connecting sheet 13 with an adhesive on its front and rear surfaces is put into freedom. As a result, the connecting sheet 13 is brought into contact with a side portion of the earlier row of inner springs 2 held by the holder 10 and adheres thereto.
At the same time as the completion of such a series of supplying operations of the connecting sheet 13, the next row of inner springs 2 held by the pawls 8, 8 of the carrying mechanism portion 3 are carried to and brought into press-contact with the connecting sheet 13. As a result, the earlier row of inner springs 2 and the next row of inner springs 2 are firmly adhesive bonded to each other through the connecting sheet 13 (See FIG. 3).
The operations mentioned above are repeated in sequence to form an assembled structure of inner springs (a mat) 21 having a predetermined width, as shown in FIG. 4.
Thus, the assembled structure of inner springs 21 is formed by the adjoining rows of inner springs 2 at each side thereof being adhesive bonded together via the connecting sheets 13 having the adhesives 20 on its front and rear surfaces and interposed each between adjoining rows of inner springs 2a, 2b, 2c, .... Hence, the expansion-and-contraction problem of the nature of the rows of inner springs 2 can be prevented by the connecting sheets 13 interposed between the rows of inner springs 2a, 2b, 2c, ..., whereby the assembled structure of inner springs 21 of good durability and precise size is produced.
In the above-illustrated embodiment, the later row of inner springs is arranged over the earlier row of inner springs, when viewed in the drawings, but this arrangement is not of restrictive. Modification may of course be made by such a manner that the earlier row of inner springs 2 and the later row of inner springs are arranged in side by side with respect of the horizontal direction and are bonded together via the connecting sheet 13.
Further, in the above-illustrated embodiment, the adhesive spray nozzles 15, 15 disposed confronting each other across the connecting sheet 13 are adapted to spray the adhesive therefrom simultaneously. This simultaneous spray is adopted due to the arrangement of in-line rows of inner springs 2. For example, in the case of the arrangement of staggered rows of inner springs, the adhesive should be sprayed alternately from the adhesive spray nozzles 15, 15 disposed confronting each other across the connecting sheet 13.

Claims

An assembled structure of the inner springs to be fit inside furniture and bedding comprising:

rows of inner springs, each row of inner springs comprising a predetermined number of coiled springs and accommodating bags with a predetermined number of spring accommodating portions arranged in series, the coiled springs in each row being accommodated one in each of the accommodating bags, the rows of inner springs being arranged in parallel and joined to each other at side walls of the spring accommodating portions, to be formed into a mat form; and

a connecting sheet of low stretching properties having front and rear surfaces and interposed between side portions of the adjoining rows of inner springs, each of the front and rear surfaces forming on at least a part thereof an adhesive bonding surface via which the adjoining rows of inner springs are connected to one another at their side portions.
An assembled structure of the inner springs to be fit inside furniture and bedding according to Claim 1, wherein the connecting sheet is formed of a non-woven fabric or a woven fabric or a knitted fabric.
An assembled structure of the inner springs to be fit inside furniture and bedding according to Claim 1, wherein the adhesive bonding surface is formed by the intermittent application of an adhesive to each of the front and rear surfaces of the connecting sheet.
An assembled structure of the inner springs to be fit inside furniture and bedding according to Claim 2, wherein the adhesive bonding surface is formed by the intermittent application of an adhesive to each of the front and rear surfaces of the connecting sheet.
A producing method for an assembled structure of inner springs to be fit inside furniture and bedding comprising the steps of:

applying an adhesive to at least a part of each surface of a connecting sheet;

bringing the connecting sheet into contact with a side surface of an earlier row of inner springs and then bringing a side surface of a next row of inner springs into press-contact with the connecting sheet so that the next row of inner springs can be adhesive bonded to a side surface of the earlier row of inner springs through the connecting sheet; and

repeating the same operations in sequence to produce an assembled structure of a mat-formed inner springs.