Appeal No. 1999-0933 Page 5
Application No. 08/512,396
From this disclosure, the examiner reaches the conclusion set forth in the answer
(pages 3-4) that
shut-off valve 32 is opened and the pump 26 is operated to extract
excess brake fluid from the wheel cylinders 8, 9 via outlet valves, 21, 45.
Note outlet valves 21, 45 are at this time opened (energized) and the inlet
valves 20, 44 are closed (de-energized) so that fluid exiting the wheel
cylinders 8, 9 can be returned to the master cylinder 3 via the pump 26,
fluid line 6 and shut-off valve 32. It is “after” the fluid is returned to the
master cylinder 3 that the control unit 52 switches the inlet valves 22, 44
and outlet valves 21, 45 to their original positions as shown in figure 1 of
Willmann and thus completes or stops the operation of the pump 26. This
process of returning the fluid from the brake wheel cylinders via the closing
of the inlet valves and the corresponding opening of the outlet valves is well
known in the art and is maintained to be the only way that fluid from the wheel
cylinder can return to the master cylinder. [Emphasis original.]
Appellants read the above disclosure at pages 11-12 of Willmann and reach
the conclusion that the control device (52) opens the shut-off valve (32) so that brake
fluid returns to the master cylinder (3) through the shut-off valve (32) at the end of
traction control and that, at the same time, the control device (52) switches other
valves (e.g., 38, 44) into their original position and terminates operation of the pump.
Thus, appellants urge that Willmann fails to teach that the pressure control valve (e.g.,
21) is switched to a position where brake fluid is expelled from the wheel cylinder to
the intake side of the pump and the pump is driven.
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