Innerspring Unit

Abstract

In order to manufacture an innerspring unit comprising pocketed springs and having an increased stability at its edge regions, in a first step, an innerspring main body comprising a plurality of first strings of pocketed springs is provided. In a subsequent second step, at least one second string of pocketed springs is attached to a lateral surface of the innerspring main body, so that the at least one second string of pocketed springs extends in a longitudinal direction of the innerspring main body. The springs of the at least one second string of pocketed springs have a spring characteristic or a spring geometry different from the springs of the plurality of first strings of the innerspring main body. The at least one second string of pocketed springs forms together with the innerspring main body the innerspring unit.

Claims

1. An innerspring unit comprising (a) an innerspring main body comprising a plurality of first strings of pocketed springs; and (b) at least one second string of pocketed springs attached to a lateral surface of the innerspring main body, so that the at least one second string of pocketed springs extends in a longitudinal direction of the innerspring main body, wherein the springs of the at least one second string of pocketed springs have a spring characteristic or a spring geometry different from the springs of the plurality of first strings of the innerspring main body.

2. The innerspring unit of claim 1, wherein at least one third string of pocketed springs is attached to a first longitudinal end of the innerspring main body and at least one fourth string of pocketed springs is attached to a second longitudinal end of the innerspring main body, wherein the springs of the at least one third string of pocketed springs and the springs of the at least one fourth string of pocketed springs have a spring characteristic different from the springs of the plurality of first strings of the innerspring main body.

3. The innerspring unit of claim 2, wherein at least one second string of pocketed springs is attached to a first lateral side surface and to a second lateral side surface of the innerspring main body, so that the springs of the second, third and fourth strings of pocketed springs form an edge area completely surrounding the first strings of pocketed springs.

4. The innerspring unit of claim 2, wherein the springs of the second, third and fourth strings of pocketed springs are configured such that a stability of the innerspring unit at an edge area thereof is increased compared to an area where the springs of the first strings of pocketed springs are arranged.

5. The innerspring unit of claim 1, wherein a pair of fleece sheets is attached to upper and lower surfaces of the innerspring main body, the fleece sheets cover the innerspring main body and laterally extend beyond the innerspring main body; and wherein the at least one second string of pocketed springs is attached to the lateral surface of the innerspring main body such that it is arranged between the pair of fleece sheets.

6. The innerspring unit of claim 1, wherein the at least one second spring of pocketed springs is glued to the innerspring main body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIGS. 1A-1D show a method for manufacturing an innerspring unit comprising pocketed springs and a corresponding innerspring unit according to an embodiment of the invention.

[0025] FIG. 2 shows an apparatus for manufacturing an innerspring unit comprising pocketed springs according to an embodiment of the invention.

[0026] FIG. 3 shows a partial side view of the apparatus of FIG. 2 to illustrate the operating principle of the apparatus.

DETAILED DESCRIPTION OF THE DRAWINGS

[0027] FIGS. 1A-FIG. 1D show different views to illustrate the manufacturing of an innerspring unit according to an embodiment of the invention.

[0028] In a first step, at a first station of an innerspring unit assembly machine, an innerspring main body may be manufactured from a plurality of first strings of pocketed springs. The first station of the innerspring unit assembly machine receives an endless string of pocketed springs and cuts this endless string of pocketed springs into the plurality of first strings of pocketed springs having an equal length. The individual first strings of pocketed springs are then attached to one another to form the innerspring main body as an array of pocketed springs being arranged in rows and columns.

[0029] In FIG. 1A, the first strings of pocketed springs, which form the core of the innerspring main body 30, are indicated by reference numeral 14. The individual strings 14 of pocketed springs may be attached to one another by gluing, for example. To ensure a sufficient stability of the innerspring main body 30 both in length and width direction, a fleece sheet 20 is attached and glued both to the upper surface and the lower surface of the innerspring main body 30. In FIG. 1A, only the lower fleece sheet 20 is shown. The dimension of the fleece sheets is such that they extend at least in the width direction beyond the innerspring main body 30, as shown in FIG. 1A.

[0030] In the embodiment of FIG. 1A, the innerspring main body 30 is manufactured with edge springs increasing the stability of the innerspring main body 30 at its longitudinal front and rear edges. To this end, one or more strings 13a, 13b of pocketed springs having a different spring characteristic or geometry than the springs of the first strings 14 are provided both at the front and rear ends of the innerspring main body 30. As indicated in FIG. 1A, for example, the springs of the strings 13a, 13b may have a smaller diameter than the springs of the strings 14, so that these edge springs increase the stability of the innerspring main body 30 at its longitudinal edges. Similar to the first strings 14 of pocketed springs, the strings 13a, 13b of pocketed springs are cut from a corresponding endless string of pocketed springs, and especially the length of the strings 13a, 13b is identical or at least similar to the length of the strings 14.

[0031] It should be noted that in case an increased stability at the longitudinal edges of the innerspring main body 30 is not desired or not necessary, the springs of the strings 13a, 13b may be omitted.

[0032] To increase the stability of the innerspring main body 30 along its lateral side edges as well, i.e., in the width direction, corresponding edge springs are attached in a further step shown in FIG. 1B.

[0033] The step shown in FIG. 1B is performed at a second station of the innerspring assembly machine and attaches one or more strings 13c, 13d of pocketed springs to both lateral surfaces of the innerspring main body 30, the springs of the one or more strings 13c, 13d of pocketed springs again have a spring characteristic different from the springs of the plurality of first strings 14 of the innerspring main body 30.

[0034] The one or more strings 13c, 13d of pocketed springs are arranged such that they extend in the longitudinal direction of the innerspring main body 30. Furthermore, the one or more strings 13c, 13d are arranged at the lateral surface or periphery of the innerspring main body 30 such that they are located between the fleece sheets 20, where they are then glued to the lateral surfaces of the innerspring main body 30.

[0035] Again, it should be noted that it is of course also possible to attach one or more strings 13c, 13d of pocketed springs to only one of the lateral surfaces of the innerspring main body 30 if it is sufficient or desired to provide only one of the later surfaces of the innerspring main body 30 with an increased stability along its longitudinal edge.

[0036] In the embodiment shown in FIGS. 1A-1D, however, the innerspring main body 30 is provided with the additional strings 13a-13d of pocketed springs such that they form a closed border area or edge area of springs having an increased stability compared to the springs of the strings 14, this border area completely surrounding the springs of the strings 14, as it is shown in FIG. 1C. Consequently, the length of the one or more lateral strings 13c, 13d of pocketed springs is such that it substantially corresponds to the longitudinal length of the innerspring main body 30, as indicated in FIG. 1B, so that—once the strings 13c, 13d have been attached to the innerspring main body 30—the desired closed edge area of the Springs having the increased stability is formed by the springs of the strings 13a-13d.

[0037] The final innerspring unit 31 comprising the innerspring main body 30 in combination with the laterally attached strings 13c, 13d of pocketed springs is shown in FIG. 1C.

[0038] FIG. 1D shows a cross-sectional view of the innerspring unit 31 through the right edge of the innerspring unit 31 shown in FIG. 1C. FIG. 1D shows that the pocketed springs of the strings 14 and the pocketed springs of the strings 13d are arranged between the two fleece sheets 20a, 20b extending along the top and the bottom of the innerspring unit 31.

[0039] FIG. 2 shows an apparatus for manufacturing an innerspring unit comprising pocketed springs according to an embodiment of the invention. FIG. 2 shows a cross-sectional view of the manufacturing apparatus.

[0040] The apparatus 40 shown in FIG. 2 is an innerspring unit assembly machine comprising substantially two stations 41 and 42. The first station 41 is provided for manufacturing the innerspring main body 30 shown in FIG. 1A, while the second station 42 is provided for manufacturing the innerspring unit 31 from the innerspring main body 30 of the first station 41 and the later strings 13c, 13d of pocketed springs, as shown in FIG. 1B.

[0041] The innerspring main body 30, including the inner strings 14 of pocketed springs as well as the fleece sheets 20a, 20b and the edge springs of the strings 13a, 13b having the increased stability at the longitudinal ends of the innerspring main body 30, is manufactured at the first station 41 which may have the structure of an innerspring unit assembly machine. This first station 41 comprises a compression unit 1 for the attachment of the fleece sheets 20a, 20b to the innerspring main body 30. In addition, the first station 41 comprises a fleece guide 2, which prevents the fabric from hanging down from the side of the springs of the innerspring main body 30 and ensures an appropriate guidance for the fleece. The product output by the first station 41 is the innerspring main body 30 as shown in FIG. 1A, for example.

[0042] The innerspring main body 30 is transported from the first station 41 to the second station 42 using a conveyor device 5. The conveyor device 5 comprises a guide 3 which, together with the fleece guide 2, serves as a lateral support, so that the innerspring main body 30 cannot move sideways during its transport from the first station 41 to the second station 42. The conveyor device 5, which may comprise one or more conveyor belts, supports the innerspring main body 30 and ensures that the fleece does not hang downward.

[0043] After the compression unit 1, the fleece sheets 20a, 20b are cut, so that the innerspring main body 30 is decoupled from the previous process performed by the first station 41 which now can continue to produce another innerspring main body. The innerspring main body 30 is transported by means of the conveyor device 5 to a mounting position specified by a sensor (not shown) where the lateral strings 13c, 13d of pocketed springs are attached to the innerspring main body 30 to form the final innerspring unit 30.

[0044] Once the innerspring main body 30 has arrived at the mounting position, a compression device 11 is activated. The compression device comprises compression plates which lightly compress the springs of the innerspring main body 30 in the lateral edge regions of the innerspring main body 30. In particular, the compression device compresses the springs 13 of the lateral strings 13c, 13d prior to their attachment to the innerspring main body 30.

[0045] A gluing device 8 is operated to apply glue along the respective lateral surface of the innerspring main body 30, as indicated at 15 in FIG. 3. According to an embodiment of the invention, when the innerspring main body 30 has reached the mounting position of the second station 42, the gluing device 8 is moved along the respective lateral surface of the innerspring main body 30 in the longitudinal direction of the innerspring main body to spray glue onto the lateral surface of the innerspring main body 30. The gluing device 8 may also be operated to apply glue to the surfaces of the fleece sheets 20a, 20b facing the strings 13c, 13d of pocketed springs.

[0046] The pocketed springs of the lateral strings 13c, 13d are each prefabricated by a respective unit per side. These units include typical components of an innerspring unit assembly machine, including a spring feeder, a changer, spring inserter, and the gluing device etc.

[0047] The respective string 13c, 13d of pocketed springs is pushed toward the innerspring main body 30 between upper and lower guide plates 4, 7 using a pushing device 10 (see FIG. 3). When the gluing device 8 has been extracted from the working position, upper and lower flaps 9 are closed as shown in FIG. 3 and are brought from a vertical open position to the closed horizontal position to close the gap to allow the pushing of the strings 13c, 13d to the innerspring main body 31.

[0048] A fleece clamping device 12 is operated to clamp the fleece sheets, so that during the pushing of the strings 13c, 13d the fleece sheets are not also pushed by the pushing device 10. In particular, the fleece clamping device 12 clamps the upper fleece sheet 20a, while the lower fleece sheet 20b may be clamped by the lower guide plate 7.

[0049] Since the springs at the edge region of the innerspring main body 30 are compressed by the compression device 11, a sufficient contact pressure can be established between the springs 14 at the edge region of the innerspring main body 30 and the springs 13 of the strings 13c, 13d pushed against the innerspring main body by the pushing device 10 as well as between the springs 13 of the strings 13c, 13d and the fleece sheets 20a, 20b. As indicated in FIG. 3, the springs 13 compressed by the compression device 11 can expand again and, consequently, press upwards and downwards once they have been pushed beyond the guide plates 4,7 by the pushing device 10. This biasing of the springs 13 ensures that the glue is pressed against the top and bottom fleece sheets. The expansion of the springs 13 preferably happens close to the end of the entire process prior to the output of the innerspring unit by the assembly machine.

[0050] In case another string 13c, 13d of pocketed springs is to be attached to the lateral surfaces of the innerspring main body 30, the process described above is repeated, so that one string 13c, 13d of pocketed springs is attached to the innerspring main body 30 after the other. Alternatively, it may also be possible to pre-fabricate sets of a number of strings 13c, 13d (for example, such as those indicated in FIG. 1B), in which the individual strings are already glued to each other, and to attach these sets in one step to the lateral surfaces of the innerspring main body 30.