A latch (50) for each of a pair of cushioning arms (18, 20), respectively, of a stair-climbing wheelchair (10). The latch (50) for each arm (18, 20) includes a first member (52) coupled to the arm (18, 20) and a second member (56) coupled to a fixed support (60) of the wheelchair (10), with the second member (56) being coupled to the armature (66) of a solenoid (68) which is energized to unlatch the arm (18, 20) from latched relationship with the support (60) when it is desired to use the arm (18, 20) for cushioning purposes. An ultrasonic transducer (80) coupled to the wheelchair (10) adjacent to each latch (50), respectively, provides signals to energize the respecting latch solenoid (68) when the arm (18, 20) is to be unlatched. To latch each arm (18, 20), the adjacent edge margins of the two members (52, 56) are bevelled so that, during upward movement of the arm (18, 20), such as by movement of the wheelchair from an inclined position to a horizontal position, the members (52, 56) are spread apart and a first spring (72) biases the two members (52, 56) back together in coupled relationship to each other. When the latch solenoid (68) is energized, the second member (56) is moved away from the first member (52) to allow a second spring (25, 27) to pull the arm (18, 20) down and into an unlatched position. A limit switch (76) senses when each arm (18, 20) is latched.
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