Electrical generator or motor structure – Dynamoelectric – Linear
Reexamination Certificate
2001-10-26
2004-03-16
Tamai, Karl (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Linear
C296S056000, C296S146800
Reexamination Certificate
active
06707173
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle liftgate and, more particularly, to a power actuator to remotely operate the vehicle liftgate.
Vans, station wagons, pick-ups, and sport-utility vehicles (SUVs) typically have rear doors, generically called tailgates, which provide access to the vehicle's rear cargo area through a rear opening. In some vehicles, pairs of doors are vertically hinged at the sides of the vehicle rear opening to open horizontally. In others, pairs of doors are horizontally hinged at the top and bottom of the rear opening to open vertically up and down like a clamshell. In yet other vehicles, a single door or liftgate is horizontally hinged at the top of the opening to open upwardly.
Liftgates are usually fitted with cylindrical devices filled with pressurized gas at the sides to provide a spring assist when the door is raised. These cylindrical devices are commonly referred to as gas springs, gas struts, gas props, gas stays, and stay dampers. The gas springs generally occupy a position in which their axis is substantially parallel to the liftgate when the liftgate is closed. In this closed position the moment arm of the gas springs is quite small. Manual effort is therefore required to both raise and lower the liftgate even though the gas springs aid lifting and gravity aids lowering. Manual operation necessitates operator presence at the liftgate for operation, which can be undesirable during inclement weather and may be difficult for some people.
Many vehicles are currently incorporating powered actuators to automatically open and close the liftgates. However, incorporating known powered actuators into the liftgate has been problematic due to the kinematics involved and the relatively large and heavy liftgates. Further, the powered actuator typically requires a rather complex mechanical override mechanism which allows the liftgate to be manually opened and closed.
Accordingly, it is desirable to provide a power operator for a liftgate which enables remote operation to both raise and lower the liftgate. It is further desirable to provide a power liftgate actuator that facilitates manual operation if the power operator becomes inoperative.
SUMMARY OF THE INVENTION
The power operating system according to the present invention provides an actuator to automatically operate a vehicle liftgate. Each actuator includes a gas spring and a linear electric motor mounted thereto along a common axis. A connector located at each end of the gas spring mounts the gas spring between the vehicle and the liftgate.
The linear electric motor includes a linear stator and a slidable rotor which is drivable relative to the linear stator. The slidable rotor is attached to a cylinder end of a gas spring from which the gas spring shaft extends. By activating the linear electric motor, the rotor moves along the linear stator to drive the actuator between an extended position and a retracted position. The power operating system thereby provides automatic remote operation of the liftgate. Moreover, when power is unavailable to or removed from the linear electric motor, the liftgate may still be manually opened and closed in the conventional manner. No complicated mechanical or electrical override is required.
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European Search Report, dated Mar. 5, 2003.
Bauman Walter Douglas
Roach Jack R.
AVM, Incorporated
Carlson & Gaskey & Olds
Jones Judson H.
Tamai Karl
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