Baby carriage

1. A baby carriage which can be changed to a form of a chair state in which a backrest portion and a head protection part positioned above the backrest portion extend on the same plane, or to a form of a bed state in which said head protection part rises upward from said backrest portion, comprising:

a body frame;

a backside support connected to said body frame so as to reclinably support said backrest portion from the backside; and

a guard member of a rigid structure having an inverted U shape as a whole in which both ends thereof are rotatably connected to said body frame and a central portion thereof extending in a width direction is positioned along a back surface of said head protection part in both said forms of the chair state and the bed state;

wherein said baby carriage has a structure adapted to shrink by being folded in the width direction, said guard member includes a pair of side bars having end portions forming said ends rotatably connected to said body frame and lateral bar having two ends thereof connected respectively to said pair of side bars, and the lateral bar of said guard member includes a pair of end link members rotatably connected to said pair of side bars and a central link member having two ends thereof rotatably connected to said pair of end link members.

2. A baby carriage according to claim 1 , wherein said body frame includes a seating surface support member and a pair of longitudinal side frame members upwardly extending from both sides at a rear end region of said seating surface support member, and said ends of said guard member are rotatably connected to said pair of longitudinal aids frame members of said body frame.

3. A baby carriage according to claim 2 , further comprising:

a seat hammock including a seating surface sheet portion extending on said seat surface support member and a backrest sheet portion connected to a rear edge of said seating surface support member and extending between said pair of longitudinal side frame members; and

a guard connecting member for connecting a backside of the upper region of said backrest sheet portion which is to be said head protection part to the central portion of said guard member,

wherein said backside support reclinably supports said backrest sheet portion from the backside.

4. A baby carriage according to claim 3 , wherein said backside support includes a backside string member extending along the whole length of the backside of said backrest sheet portion in the width direction and having both ends connected to said pair of longitudinal frame members.

5. A baby carriage according to claim 1 , further comprising a push rod having lower ends rotatably connected to said body frame so as to be changed to be in a backside pushing state or to be in a face-to-face pushing state.

6. A baby carriage according to claim 1 , wherein said lateral bar of said guard member has a flat configuration which is long in an extending direction of said side bars.

7. A baby carriage according to claim 1 , wherein said end link members constitute a four-section chain mechanism which moves the central link member in parallel along the back surface of the head protection part.

8. A baby carriage according to claim 1 , wherein said baby carriage has a foldable structure in which a pair of front wheels and a pair of rear wheels come near to one another in a forward and backward direction and in a lateral direction when said baby carriage is folded.