Steering wheel heater and steering wheel

1. A steering wheel heater comprising:

a heating wire;

a first connecting member connected to a first end of the heating wire, the first connecting member being externally connected;

a second connecting member connected to a second end of the heating wire, the second connecting member being externally connected;

a lead-out wire connected to a portion between the first end and the second end which is a point along a wiring pattern formed of the heating wire; and

a third connecting member connected to the lead-out wire, the third connecting member being externally connected, wherein

the first connecting member or the second connecting member is connected to an external power line through which a direct-current passes, the third connecting member being connected to an external signal line.

2. The steering wheel heater according to claim 1 , wherein

the wiring pattern includes a wiring pattern formed by repeatedly bending the heating wire in a plane, and forms a planar heating element having flexibility.

3. The steering wheel heater according to claim 1 , wherein

the heating wire includes a first heating wire having a first end and a second end, and a second heating wire having a first end and a second end, and

the lead-out wire includes a first lead-out wire connected to the second end of the first heating wire and a second lead-out wire connected to the first end of the second heating wire.

4. The steering wheel heater according to claim 3 , wherein

the first connecting member is connected to the first end of the first heating wire, and

the second connecting member is connected to the second end of the second heating wire.

5. The steering wheel heater according to claim 3 , wherein

a plurality of the third connecting members are provided for the first lead-out wire and the second lead-out wire in one-to-one correspondence and connected with each other through a lead wire.

6. The steering wheel heater according to claim 1 , wherein

the wiring pattern formed of the heating wire is a series wiring pattern which has no branch between the first end and the second end.

7. A steering wheel comprising:

a first heating wire;

a second heating wire;

a power line to which a first end of the first heating wire and a first end of the second heating wire are connected in common;

a ground line to which a second end of the first heating wire and a second end of the second heating wire are connected in common;

a first lead-out wire connected to a point along a wiring pattern formed of the first heating wire;

a second lead-out wire connected to a point along a wiring pattern formed of the second heating wire;

a first contact detection circuit electrically connected to the first wiring pattern through the first lead-out wire; and

a second contact detection circuit electrically connected to the second wiring pattern through the second lead-out wire, wherein

a portion of the first wiring pattern formed of the first heating wire is connected in series between the ground line and the first contact detection circuit,

a portion of the second wiring pattern formed of the second heating wire is connected in series between the ground line and the second contact detection circuit, and

the first wiring pattern formed of the first heating wire and the second wiring pattern formed of the second heating wire are included on left and right, respectively, of the steering wheel.

8. The steering wheel according to claim 7 , further comprising

a first switch connected to the power line, wherein

the power line is connected via the first switch to the first end of the first heating wire and the first end of the second heating wire.

9. The steering wheel according to claim 8 , further comprising

a second switch connected to the ground line, wherein

the ground line is connected via the second switch to the second end of the first heating wire and the second end of the second heating wire.