An unmanned aerial vehicle according to certain embodiments generally includes a chassis, a control system, and at least one rotor. The chassis includes a first battery compartment configured to receive sliding insertion of a first battery, and a second battery compartment configured to receive sliding insertion of a second battery. The control system is operable to receive power from the first battery and the second battery when the first battery is received in the first battery compartment and the second battery is received in the second battery compartment. The at least one rotor is operable to generate lift under control of the control system when both the first battery and the second battery are installed to the chassis. The control system is configured to remain at least partially active under power supplied by the first battery when the second battery is removed from the second battery compartment.

A method according to certain embodiments generally involves operating a system including an unmanned aerial vehicle (UAV) and a base station. The base station includes a nest including an upper opening having an upper opening diameter and a lower opening having a lower opening diameter less than the upper opening diameter. The lower opening is accessible from within the base station. The method generally includes landing the UAV within the nest such that a portion of the UAV is accessible via the lower opening, releasably attaching a load to the UAV, and operating the UAV to deliver the load to a destination.

An example carriage is configured for mounting to an unmanned aerial vehicle. The carriage generally includes a housing assembly configured for mounting to the unmanned aerial vehicle, a movable grip mounted to the housing assembly for movement between a capturing position and a releasing position, a latch device, and a driver. The latch device has a latching state and an unlatching state, is configured to retain the movable grip in the capturing position when the latch device is in the latching state, and is configured to permit movement of the movable grip from the capturing position to the releasing position when in the unlatching state. The driver is operable to transition the latch device from the latching state to the unlatching state.

An example charging station for an unmanned aerial vehicle (UAV), the charging station generally including a nest and a charging device. The nest includes an upper portion and a lower portion. The upper portion defines an upper opening sized and shaped to receive a landing apparatus of the UAV, and a diameter of the nest reduces from a first diameter at the upper opening to a second diameter at the lower portion. The charging device is mounted in the nest, and includes a first contact pad and a second contact pad. The charging device is configured to apply a voltage differential across the first contact pad and the second contact pad such that the charging station is operable to charge a power supply of the UAV via the landing apparatus.

An unmanned aerial vehicle according to certain embodiments generally includes a chassis, a power supply mounted to the chassis, a control system operable to receive power from the power supply, a plurality of arms extending outward from the chassis, a plurality of rotors, and a support structure mounted atop the chassis. Each rotor is mounted to a corresponding arm of the plurality of arms, is in communication with the control system, and is operable to generate lift under control of the control system. The support structure includes a plurality of arched struts that connect to one another at an apex region of the support structure.

An unmanned aerial vehicle according to certain embodiments generally includes a chassis, a power supply mounted to the chassis, a control system operable to receive power from the power supply, at least one rotor operable to generate lift under control of the control system, and a motor operable to lower a free end of a line. The free end of the line is operable to engage a parcel to be delivered by the unmanned aerial vehicle. The control system is configured to operate the motor to cause the free end of the line to accelerate toward a delivery surface as the free end of the line passes through a first portion of a distance between the unmanned aerial vehicle and the delivery surface, and to decelerate as the free end of the line passes through a lower portion of the distance.

A hook system has a mount that includes a first sidewall comprising a concave profile on a longitudinal end of the first sidewall, a second sidewall laterally offset in a fixed location relative to the first sidewall and defining a channel therebetween, the second sidewall having a second concave profile on a longitudinal end of the second sidewall. The hook system also has a first pin structure extending between the first sidewall and the second sidewall and a connector. The connector has a third concave profile, the third concave profile being configured to receive the first pin structure therein. The hook system also includes a second pin structure extending through the connector, wherein each of the first concave profile and the second concave profile are configured to receive the second pin structure therein. The connector is configured to be at least partially received within the channel.

A hook system has a mount that includes a first sidewall comprising a concave profile on a longitudinal end of the first sidewall, a second sidewall laterally offset in a fixed location relative to the first sidewall and defining a channel therebetween, the second sidewall having a second concave profile on a longitudinal end of the second sidewall. The hook system also has a first pin structure extending between the first sidewall and the second sidewall and a connector. The connector has a third concave profile, the third concave profile being configured to receive the first pin structure therein. The hook system also includes a second pin structure extending through the connector, wherein each of the first concave profile and the second concave profile are configured to receive the second pin structure therein. The connector is configured to be at least partially received within the channel.

A load lifting hook assembly includes a body, a hook coupled to the body, a fluid connection on the body and connectable to a pressurized fluid source, a piston and a pressure relief valve. The piston is extendable from the body to engage the hook and lock the hook in a closed position relative to the body. The piston is configured to receive pressurized fluid from the fluid connection tending to urge the piston out of engagement with the hook. The pressure relief valve is positioned in the body in communication with the fluid connection and configured to prevent excess pressure in the pressurized fluid from acting on the piston.

A load lifting hook assembly includes a body, a hook coupled to the body, a fluid connection on the body and connectable to a pressurized fluid source, a piston and a pressure relief valve. The piston is extendable from the body to engage the hook and lock the hook in a closed position relative to the body. The piston is configured to receive pressurized fluid from the fluid connection tending to urge the piston out of engagement with the hook. The pressure relief valve is positioned in the body in communication with the fluid connection and configured to prevent excess pressure in the pressurized fluid from acting on the piston.