A vehicular propulsion system is described that uses a plurality of direct current (DC) motors operatively attached to a common drive shaft or shafts of an electric vehicle (EV) or boat. Each motor is powered separately by direct current from a battery cassette or trays swappably inserted into the chassis of the vehicle. The battery cassettes are secured in racks, with one or more individual battery cassettes connected to each of individual motors. The individual battery cassettes are sized to have a weight suitable so as to be readily swapped out as needed for recharging, maintenance or replacement, enabling vehicle range to be extended en route by exchanging depleted battery cassettes for new batteries whenever needed. Air cooling is enabled by use of the smaller battery cassettes and smaller motor assemblies. The torque of the smaller motors, operating on a common drive shaft, is additive according to a first embodiment in which a set of like motors are supplied. Variable ratio gearboxes are provided in the drivetrain so that motors can be directly coupled to the driven axle. By dividing the batteries among the motor loads and by combining the torques of several smaller motors at the drive shaft, improved range, serviceability and decreased cost are achieved. According to a second embodiment in which a set of unlike motors are supplied, unlike motors having torque curves optimized for different propulsion states are combined so as to improve mileage in a range of real world mixed driving conditions. Series-wound DC motors may be used in combination with brushless direct current (BLDC) motors (operated with Hall-effect positional feedback, encoders, resolvers, H-bridge MOSFETs, field-oriented control or pulse width modulation), shunt-excited motors, or compound-excited DC motors. With both like and unlike DC motors, magnetic coupling of surface, radial or embedded permanent magnets (PM) may be selected to obtain efficiencies greater than obtainable with AC motors, but require no expensive inverter unit.

In an electrical traction drive for a vehicle comprising at least two individual wheel drives that are to be controlled independently of each other, the drives are able to be operated redundantly in order for an emergency operating function to be implemented.

A drive mechanism includes a mount block extending along an axis and a plurality of electric motors supported by the mount block. The electric motors are arranged in series along the axis to define an initial electric motor, one or more intermediate electric motors, and a final electric motor. The drive mechanism also includes a gear mounted to each of the electric motors, and an output member driven by the gear mounted to the final electric motor to receive the combined rotational torque from the gears of the series of electric motors.

A drive mechanism includes a mount block extending along an axis and a plurality of electric motors supported by the mount block. The electric motors are arranged in series along the axis to define an initial electric motor, one or more intermediate electric motors, and a final electric motor. The drive mechanism also includes a gear mounted to each of the electric motors, and an output member driven by the gear mounted to the final electric motor to receive the combined rotational torque from the gears of the series of electric motors.

A lift assembly includes a base, a platform coupled to the base and moveable between a lowered state and an elevated state, a first pair of scissor arms including a first arm and a second arm pivotably connected to one another, and a second pair of scissor arms including a third arm and a fourth arm pivotably connected to one another. The lift assembly also includes a carriage coupled to the first pair of scissor arms and to the second pair of scissor arms. The carriage includes a shaft extending transverse to the first arm, the second arm, the third arm, and the fourth arm, and a centering wheel rotatably coupled to the shaft. The first arm includes a cam surface engageable with the centering wheel to guide travel of the platform between the lowered state and the elevated state.

A lift assembly includes a base, a platform coupled to the base and moveable between a lowered state and an elevated state, a first pair of scissor arms including a first arm and a second arm pivotably connected to one another, and a second pair of scissor arms including a third arm and a fourth arm pivotably connected to one another. The lift assembly also includes a carriage coupled to the first pair of scissor arms and to the second pair of scissor arms. The carriage includes a shaft extending transverse to the first arm, the second arm, the third arm, and the fourth arm, and a centering wheel rotatably coupled to the shaft. The first arm includes a cam surface engageable with the centering wheel to guide travel of the platform between the lowered state and the elevated state.