Abstract: An energy-absorbing crush tower for a vehicle bumper system includes a tube made of a continuous contiguous material, such as a heat-treatable steel. The tube has first and second ring sections connected by an interconnecting section. The first ring section is heat-treated to a high material strength, such as about 120 KSI tensile strength, which is substantially higher than the second ring section, which is kept at about 60 KSI tensile strength. The interconnecting section has a frustoconically-shaped portion forming a ramp. By this arrangement, upon the bumper system receiving an end impact parallel a length of the tube, the first and second ring sections telescopingly collapse with a predictable and consistent multi-phase deformation sequence where a third ring section forms between the first and second ring sections. A method related to the above is also disclosed and claimed.

Abstract: An energy-absorbing crush tower for a vehicle bumper system includes a tube made of a continuous contiguous material, such as a heat-treatable steel. The tube has first and second ring sections connected by an interconnecting section. The first ring section is heat-treated to a high material strength, such as about 120 KSI tensile strength, which is substantially higher than the second ring section, which is kept at about 60 KSI tensile strength. The interconnecting section has a frustoconically-shaped portion forming a ramp. By this arrangement, upon the bumper system receiving an end impact parallel a length of the tube, the first and second ring sections telescopingly collapse with a predictable and consistent multi-phase deformation sequence where a third ring section forms between the first and second ring sections. A method related to the above is also disclosed and claimed.

Abstract: A method and apparatus for controlling stepmotors having a broad range of applications including fuel control for gas-turbine engines, and operating powered automatically controlled doors for mass transit vehicles is disclosed. Step motor control through analysis of the motor winding currents during application of controlled voltage pulse provides a basis for evaluating shaft torque conditions at the motor load without return or feedback signals from the driven load. This type of current analysis utilizing digital techniques provides a convenient, reliable, and economical means for detecting stepmotor output shaft position and loading. Detection and recognition of output shaft load or drive requirements is then utilized in a control system wherein functional requirements of the system including motion and/or torque requirements of the shaft output load can be controlled in accordance with desired system operation.