Setting-up sheet counters
AssigneePelcombe Limited
InventorDavid Brian Long
Life of this patent
Estimating the term…
Abstract
A sheet counter has an elongate element (18) in which is formed a suction port (19), connected to a vacuum source by a duct (26). A pressure sensor is arranged to sense the pressure in the duct, in the vicinity of the port (19), and produces an electrical signal indicative thereof. The counter is set up by sensing the pressure in the duct with the port (19) open, either with the vacuum source operating or before operation thereof, and then by sensing the pressure in the duct with the port closed and the vacuum source operating. A pressure count-value part-way between the two sensed pressures is computed and during subsequent operation of the counter, a valid count signal is generated only if the instantaneous sensed pressure in the duct falls below the computed count-value.
Claims10
A method of setting-up a sheet counter before the commencement of a counting operation, which counter includes an element having a suction port over which the sheets to be counted are caused to lie in sequence one after another, a source of sub-atmospheric pressure connected by a duct to the port, and means to sense the pressure within the duct in the vicinity of the port which sensing means provides an electrical signal indicative of sensed pressure, in which method the port is left open and the pressure in the duct is sensed to obtain a first pressure, either before said source is operated to draw air through the port or after operation of said source has commenced;
- the source is operated and the port in the element is covered whereafter the pressure in the duct is sensed again to obtain a second pressure;
- and a count pressure value part-way between the first and second pressures is computed, a valid count signal in a subsequent counting operation being generated only if the instantaneous sensed pressure falls below the count pressure value.
Dependencies are inferred from the claim text.