Patent ID: 11932393
Assignee: RAKUTEN GROUP, INC.
Field: Transport (Mechanical engineering)
Classification: CPC B | IPC B

Claim 9:
10. A load-lowering device mountable to an aerial device body capable of flying while unmanned, and configured to lower a load from the aerial device body staying in midair, the load-lowering device comprising:
a linear member holder for holding a linear member having one end portion connectable to the load, the linear member holder holding at least an other end portion of the linear member, wherein the linear member holder includes a rotary shaft with a reel attached, wherein the linear member is wound around the reel;
a speed limiting mechanism that limits a speed at which the linear member is pulled out of the linear member holder, under a weight of the load, wherein the speed limiting mechanism provides rotational resistance to the rotary shaft or the reel, wherein the speed limiting mechanism has a rotor that is rotatable together with the rotary shaft, a stator that is not rotatable, and a spring that generates a frictional force by bringing the rotor and the stator into pressure contact with each other, and wherein a static torque applied by the spring to the rotary shaft by a maximum static frictional force acting between the rotor and the stator when the rotary shaft is not rotated becomes smaller than a torque that is applied by the weight of the load and that acts to rotate the reel; and
a landing detection unit that detects that the load has landed based on the rotary shaft ceasing rotation after the load-lowering device has begun lowering the load.