Abstract: To prevent damaging the rotary reciprocating knives and/or the cups which hold the fruit in a pimento coring machine caused by non-synchronous operation of the fruit conveyor and the reciprocating knife carriage, a sensing probe on the carriage near its lower end engages a roller of the chain to prevent complete descent of the knife carriage, thus protecting the knives and cups when the non-synchronous condition exists. When the chain is properly synchronized with the knife carriage, the probe can enter a space between two rollers and two side links of the dwelling chain so as to allow full descent of the knife carriage and knives.