SHIFTER WITH SHAPE MEMORY ALLOY AND SAFETY
First Claim
1. An actuator comprising:
- a housing;
a sliding member slidably engaging the housing;
a spring biasing the sliding member in a first direction;
a blocking member operably mechanically connected to the sliding member;
a length of shape memory alloy SMA wire attached to the housing and configured to move the sliding member in a second direction opposite the first direction when current is passed through the SMA wire to change a length of the SMA wire; and
a control circuit for controlling the current including at least one switching element that is operably connected to the SMA wire for controlling current flow thereto.
1 Assignment
0 Petitions
Accused Products
Abstract
A shifter incorporates a shape memory alloy wire (SMA actuator) to control movement of a blocker to selectively prevent moving a shift lever (or pawl) out of its park position until predetermined vehicle conditions are met. A mechanical fuse (i.e., flexible overload spring) prevents damage to the SMA actuator where the shift lever (or pawl) can be frictionally stopped from movement despite the contraction of the SMA actuator. The control circuit for the SMA actuator includes a photo-electric switch for stopping electrical power to the SMA actuator when the shift lever is moved from its park position, and the shift lever includes structure for mechanically continuing to hold the switch open while out of park. Further, the control circuit is operably connected to an ignition key retaining mechanism so that the ignition key cannot be removed when the lever is not in its park position.
52 Citations
26 Claims
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1. An actuator comprising:
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a housing; a sliding member slidably engaging the housing; a spring biasing the sliding member in a first direction; a blocking member operably mechanically connected to the sliding member; a length of shape memory alloy SMA wire attached to the housing and configured to move the sliding member in a second direction opposite the first direction when current is passed through the SMA wire to change a length of the SMA wire; and a control circuit for controlling the current including at least one switching element that is operably connected to the SMA wire for controlling current flow thereto. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A shifter comprising:
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a shifter base including notches defining gear shift positions and a park position; a shift lever pivoted to the base and including a pawl for selectively engaging the notches to control movement of the shift lever between at least some gear shift positions and the park position; and an actuator comprising a housing, a sliding member slidably mounted to the housing, a slide-biasing spring biasing the sliding member, a first blocking member having a home position for blocking one of the pawl and the lever in the park position and movable to a pawl-released position, a length of shape memory alloy SMA wire attached to the housing and operably engaging the sliding member to move the sliding member against the slide-biasing spring when current is passed through the wire, and a control circuit controlling current flow to the SMA wire, the control circuit including at least one switching element in communication with the first blocking member so that the switching element changes states when the first blocking member is moved from the home position. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. An actuator comprising:
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a housing; a movable member positioned therein for movement between a home position and a second position different from the first position, including a spring biasing the movable member toward the home position; a length of shape memory alloy SMA wire attached to the housing and engaging the sliding member so that when current passes through the SMA wire and the length changes dimension, the movable member is moved from the home position toward the second position; and a switch having first and second operating conditions and located near the movable member and further being configured to be engaged and switched between the operating conditions upon movement of the movable member between the home and second positions. - View Dependent Claims (21)
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22. An apparatus comprising:
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a shifter base defining gear shift positions including a park position; a shift lever with spring-biased pawl; a blocker positioned to selectively prevent movement out of the park position by engaging one of the shift lever and the pawl; an actuator including a shape memory alloy SMA wire for controlling movement of the blocker between a locking position preventing movement out of the park position and a release position permitting movement out of the park position; and a control circuit connected to the actuator and adapted for connection to vehicle sensors to operate when predetermined vehicle conditions are met, the control circuit including a switch movable from a home position to a second position upon moving one of the lever or pawl, the switch being electrically connected to the actuator and also to a vehicle functional component for affecting controlled operation of the actuator and the functional component. - View Dependent Claims (23, 24)
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25. An apparatus comprising:
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a shifter base defining gear shift positions including a park position; a shift lever with spring-biased pawl; a blocker positioned to selectively prevent movement out of the park position by engaging one of the shift lever and the pawl; a bell crank engaging the blocker; an actuator including shape memory alloy SMA wire for operating the bell crank to control movement of the blocker between a locking position preventing movement out of the park position and a release position permitting movement out of the park position; a control circuit for controlling the actuator; and a strain relief mechanism on one of the blocker, the bell crank, and the actuator that is configured to allow movement of the actuator without corresponding movement of the blocking member to thus avoid damage to the SMA wire. - View Dependent Claims (26)
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Specification