BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a seat core mounted on a child-care instrument such as a baby carriage, a child safety seat, a baby bed/chair or the like, to form a seat and more particularly, it relates to a seat core mounted on a child-care instrument which can be switched between a state of chair and a state of bed.

[0003] 2. Description of the Background Art

[0004] FIGS. 1 and 2 show baby carriages disclosed in Japanese Unexamined Patent Publication No. 8-175395. The baby carriage 1 comprises a body 2 and a seat hammock 3 mounted on the body 2 to form a seat.

[0005] The baby carriage 1 is constituted so as to be switched between a state of chair shown in FIG. 1 and a state of bed shown in FIG. 2. Although it is not shown in the drawings, the baby carriage 1 is constituted such that front and rear wheels come close and side wheels come close such that a width dimension is reduced when it is folded.

[0006] FIG. 3 shows the general seat hammock 3 which has been conventionally used. The seat hammock 3 comprises a backrest surface portion 4 supporting a back of a child from behind, a seating surface portion 5 supporting buttocks of the child from beneath, a head guard surface portion 8 rising from an upper edge of the backrest surface portion 4 in the state of bed, and a pair of upper side surface portions 7 rising from both side edges of the backrest surface portion 4 in the state of bed especially.

[0007] As can be clear from comparison between FIGS. 1 and 2, the baby carriage 1 is constituted such that the seating surface can be extended when it becomes in the state of bed. Legs of the child can be supported by the seating surface extension portion from beneath. The seat hammock 3 has a leg-supporting surface portion 6 forming this seating surface extension portion. In the state of chair shown in FIG. 1, the leg-supporting surface portion 6 of the seat hammock 3 which formed the seating surface extension portion hangs downward.

[0008] FIG. 4 is a sectional view taken along line 4-4 in FIG. 3. As shown in FIG. 4, a head guard surface core 8a, a backrest surface core 4a and a seating surface core 5a are contained in the head guard surface portion 8, the backrest surface portion 4 and the seating surface portion 5 of the seat hammock 3, respectively. Meanwhile, there is no core in the leg-supporting surface portion 6 of the seat hammock 3 and only a sewed cloth exists there. Hinge portions 9 and 10 formed of a sewed cloth are formed between the seating surface portion 5 and the backrest surface portion 4, and between the backrest surface portion 4 and the head guard surface portion 8, respectively.

[0009] The body 2 of the baby carriage 1 has a seating surface extension member which can be drawn frontward from a seating surface supporting member, in order to extend the seating surface frontward in the state of bed. One example of the seating surface extension member is in the shape a flat plate formed of a resin. Since a rib or recess is formed in the seating surface extension member in the shape of the resin flat plate, a concave and convex configuration is provided on its surface.

[0010] Another example of the seating surface extension member comprises a pair of side pulling rods pulled frontward from both sides of the seating surface supporting member, and a flexible belt provided between the pair of side pulling rods.

[0011] When the baby carriage 1 is switched to the state of bed, the leg-supporting surface portion 6 of the seat hammock 3 is spread on the seating surface extension member. Since the leg-supporting surface portion 6 is formed of the sewed cloth, touch of the concave and convex configuration in the seating surface extension member in the shape of the flat plate of resin is felt under feet or legs of the child. In addition, according to the one which supports the leg-supporting surface portion 6 from beneath by the flexible belt, since there is a downward drop, the feet or legs of the child cannot be stably supported.

[0012] Furthermore, as can be clear from FIG. 4, there is formed a stepped portion between the seating surface portion 5 having the seating surface core 5a and the leg-supporting surface portion 6 formed only the sewed cloth because of the thickness of the core. This stepped portion gives the child a feeling of discomfort. Similarly, since the hinge portion 9 formed of only the sewed cloth provides a relatively large concave portion, this also gives the child a feeling of discomfort.

SUMMARY OF THE INVENTION

[0013] It is an object of the present invention to provide a seat core which can form a smooth plane for the whole of a bed surface when a child-care instrument is in a state of bed.

[0014] A seat core of a child-care instrument according to the present invention is mounted on the child-care instrument which can be switched between a state of chair and a state of bed, to form a seat, and provided separately from the child-care instrument itself. The seat core continuously comprises a backrest surface portion supporting a back of a child from behind, a seating surface portion supporting buttocks of the child from beneath, a leg-supporting surface portion supporting legs of the child from beneath in the state of bed, a first hinge portion positioned between the backrest surface portion and the seating surface portion in order to enable a slanting operation of the backrest surface portion, and a second hinge portion positioned between the seating surface portion and the leg-supporting surface portion in order to enable the leg-supporting surface portion to be bent from the seating surface portion.

[0015] According to the above constitution, since the seat core has the leg-supporting surface portion continued from the seating surface portion, there is no stepped portion between the seating surface portion and the leg-supporting surface portion. In addition, since the leg-supporting surface portion has the core, even when a seating surface extension member has a concave and convex configuration or it is formed of a belt, touch of the concave and convex configuration is not felt under the child and there is no drop in the leg-supporting surface portion. Still further, since the core of the backrest surface portion and the core of the seating surface portion are continuously formed, there is no large concave portion between them.

[0016] According to one embodiment, the backrest surface portion, the seating surface portion, the leg-supporting surface portion, the first hinge portion and the second hinge portion are integrally formed of a common member. In this case, the first and second hinge portions are formed by reducing thicknesses of the relevant cores, for example. The seat core is in the shape of a sheet of a plate formed of a synthetic resin, for example. Thus, there can be provided a comfortable bed surface for the child with very simple constitution.

[0017] As another embodiment, the first hinge portion includes a first hinge tape attached onto an abutting portion between the backrest surface portion and the seating surface portion, and the second hinge portion includes a second hinge tape attached onto an abutting portion between the seating surface portion and the leg-supporting surface portion. In this case also, since the core forming the backrest surface portion, the core forming the seating surface portion and the core forming the leg-supporting surface portion are continuously formed, the smooth bed surface can be provided.

[0018] As a preferable embodiment, the seat core continuously comprises a head guard surface portion rising from an upper edge of the backrest surface portion in the state of bed and a third hinge portion positioned between the backrest surface portion and the head guard surface portion in order to enable a rising operation of the head guard surface portion. According to this constitution, since the core of the head guard surface portion continued from the backrest surface portion protects the top of head of the child, it is preferable in respect of safety.

[0019] As a further preferable embodiment, the seat core further continuously comprising a pair of upper side surface portions rising from both side edges of the backrest surface portion in the state of bed and a fourth hinge portion positioned between the backrest surface portion and each upper side surface portion in order to enable a rising operation of the upper side surface portion. According to this constitution, since the core of the upper side surface portion continued from the backrest surface portion protects the sides of head of the child, it is preferable in respect of safety.

[0020] In a case of the child-care instrument which reduces its dimension in the width direction to be folded, in order to be able to be shrunk in the width direction, preferably, the seating surface portion continuously comprises a center seating surface portion, a pair of side seating surface portions connected to both side edges of the center seating surface portion and a fifth hinge portion positioned between the center seating surface portion and each side seating surface portion in order to enable a bending operation of each side seating surface portion from the center seating surface portion. According to this constitution, a size in the width direction can be reduced when folded, while a large area of the seating surface portion is provided when used.

[0021] From the similar point of view, according to one embodiment, the leg-supporting surface portion continuously comprises a center leg-supporting surface portion, a pair of side leg-supporting surface portions connected to both side edges of the center leg-supporting surface portion and a sixth hinge portion positioned between the center leg-supporting surface portion and each side leg-supporting surface portion, in order to enable a bending operation of each leg-supporting surface portion from the center leg-supporting surface portion. According to this constitution, a size in the width direction can be reduced when folded, while a large area of the seating surface portion is provided when used.

[0022] As the child-care instrument, there are a baby carriage, a child safety seat, a baby bed/chair and the like. According to one embodiment, the seat core is mounted on a baby carriage. In this case, the seat core is put in a seat hammock of the baby carriage, for example. As another embodiment, the seat core may be mounted on a body of the baby carriage and the seat hammock is provided on the seat core.