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.

Abstract: A rotor assembly for counting sheets in a stack has a support on which is rotatably mounted a rotor such that the rotor engages an edge region of the stack. The rotor has a plurality of helical transfer grooves through which sheets are transferred one at a time from one side of the rotor to the other. A foot bears on the rotor and has a port which, as the rotor rotates, comes into and out of communication with further ports on the rotor each leading to a respective groove, whereby air is drawn in a timed relationship through the rotor to assist the transfer of sheets through the helical grooves. The rotor is movable axially with respect to its support and there is a detector arranged to detect the position of the foot with respect to the support thereby to give an output indicative of the position of the rotor with respect to the support.

Abstract: A sheet counter has a blade (13) for insertion between adjacent sheets of a stack thereof, and a pin (15) which orbits around the blade to transfer sheets from one side of the blade to the other. A carrier (37) defines three axes disposed in a generally triangular arrangement, the pin (15) being mounted on one of the axes, and the carrier being coupled to a crank (36) about another axis. A link (42) is pivoted at one end to the carrier (37) and at its other end to a fixed part of the counter. As the pin (15) orbits around the blade (13) on rotation of crank (36), the blade is oscillated about an axis adjacent the edge inserted furthest into the sheet stack by a crank (30) and connecting rod (31), driven synchronously with crank (36). Suction is applied in a timed manner to a hole (45) in the blade (13), to assist the separation of the sheets one at a time, before the transfer thereof to the other side of the blade by pin (15).

Abstract: A counter for counting the number of sheets in a stack has a rotor (12) which engages in an edge region of the stack and transfers sheets one at a time from one side of the rotor to the other upon rotor rotation. The rotor (12) is mounted on a shaft (13) carried by a carriage (36) arranged for sliding movement on guides (41). A motor (44) drives a lead screw (43), whereby the carriage is driven along the guides. The rotor (12) may float on its shaft (13) and its position is sensed by detector (39, 40); the output of the detector is used to control motor (44) whereby the carriage is driven substantially continuously and smoothly at a rate appropriate for a counting operation being performed.

Abstract: A rotor (10) for use in a counter to count the number of sheets in a stack has a number of transfer grooves (13), leading generally helically from the upper surface (11) to the lower surface (12) of the rotor (10). Each groove (13) has a number of suction ports (15) communication through internal passageways in the disc to a source of low pressure, to draw the next sheet in a stack to be counted into the transfer groove. The rotor also defines a reject slot (32) and in a finger (23) overlying part of the rotor surface leading into the transfer groove (13), there are further ports (25), to which suction is applied in a timed relationship to rotor rotation. If the rotor should pick-up two overlying sheets, suction through the further ports (25) will separate the two sheets and the upper sheet will be rejected out of the reject slot (32) to be counted on the next count cycle, whilst the lower sheet continues into the transfer groove (13), to be counted normally.